Pretreatment Solution for Water Recovery Systems

NASA Technical Reports Server (NTRS)

Muirhead, Dean (Inventor)

2018-01-01

Chemical pretreatments are used to produce usable water by treating a water source with a chemical pretreatment that contains a hexavalent chromium and an acid to generate a treated water source, wherein the concentration of sulfate compounds in the acid is negligible, and wherein the treated water source remains substantially free of precipitates after the addition of the chemical pretreatment. Other methods include reducing the pH in urine to be distilled for potable water extraction by pretreating the urine before distillation with a pretreatment solution comprising one or more acid sources selected from a group consisting of phosphoric acid, hydrochloric acid, and nitric acid, wherein the urine remains substantially precipitate free after the addition of the pretreatment solution. Another method described comprises a process for reducing precipitation in urine to be processed for water extraction by mixing the urine with a pretreatment solution comprising hexavalent chromium compound and phosphoric acid.

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

USDA-ARS?s Scientific Manuscript database

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...

Use of glucose as reductant to recover Co from spent lithium ions batteries.

PubMed

Meng, Qi; Zhang, Yingjie; Dong, Peng

2017-06-01

A hydrometallurgical leaching process has been developed for recovery of Co and Li from cathode material (LiCoO 2 ) collected from spent LIBs using a mix solution of glucose and phosphoric acid. The spent LiCoO 2 before and after leaching process are analyzed by scanning electron microscopy. A leaching rate of about 98% Co and nearly 100% Li is presented with 1.5mol/L phosphoric acid and 0.02mol/L glucose at 80°C in about 2h. During leaching process, glucose was oxidized into monocarboxylic acid with reduction of Co(III) to Co(II). Co in solution was recovered as Co-oxalate after leaching process. Using glucose as reductant to dissolve LiCoO 2 with chelating agent of phosphoric acid is achieved here. Copyright © 2017 Elsevier Ltd. All rights reserved.

SEPARATION OF PLUTONIUM FROM URANIUM AND FISSION PRODUCTS

DOEpatents

Boyd, G.E.; Adamson, A.W.; Schubert, J.; Russell, E.R.

1958-10-01

A chromatographic adsorption process is presented for the separation of plutonium from other fission products formed by the irradiation of uranium. The plutonium and the lighter element fission products are adsorbed on a sulfonated phenol-formaldehyde resin bed from a nitric acid solution containing the dissolved uranium. Successive washes of sulfuric, phosphoric, and nitric acids remove the bulk of the fission products, then an eluate of dilute phosphoric and nitric acids removes the remaining plutonium and fission products. The plutonium is selectively removed by passing this solution through zirconium phosphate, from which the plutonium is dissolved with nitric acid. This process provides a convenient and efficient means for isolating plutonium.

Solubility limits of dibutyl phosphoric acid in uranium-nitric acid solutions

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

Pierce, R.A.

2000-01-04

The Savannah River Site has enriched uranium (EU) solution that has been stored since being purified in its solvent extraction processes. The concentrations in solution are approximately 6 g/L U and 0.1 M nitric acid. Residual tributylphosphate in solution has slowly hydrolyzed to form dibutyl phosphoric acid (HDBP) at concentrations averaging 30--50 mg/L. Dibutyl phosphoric acid, in turn, is in equilibrium with (HDBP){sub 2} and DBP{sup {minus}}. Uranium can form compounds with the dibutylphosphate ion (DBP{sup {minus}}) which have limited solubility, thereby creating a nuclear criticality safety issue. Literature reports and earlier SRTC tests have shown that it is feasiblemore » to precipitate U-DBP solid during the storage and processing of EU solutions. As a result, a series of solubility experiments were run at nitric acid concentrations from 0--4.0 M HNO{sub 3}, uranium at 0--90 g/L, and temperatures from 0--30 C. The data shows temperature and nitric acid concentration dependence consistent with what would be expected. With respect to uranium concentration, U-DBP solubility passes through a minimum between 6 and 12 g/L U at the acid concentrations and temperatures studied. However, the minimum shows a slight shift toward lower uranium concentrations at lower nitric acid concentrations. The shifts in solubility are strongly dependent upon the overall ionic strength of the solution. The data also reveal a shift to higher DBP solubility above 0.5 M HNO{sub 3} for both 6 g/L and 12 g/L uranium solutions. Analysis of U-DBP solids from the tests identified distinct differences between precipitates from less than 0.5 M solutions and those from greater than 4 M acid. Analyses identified UO{sub 2}(DBP){sub 2} as the dominant compound present at low acid concentrations in accordance with literature reports. As the acid concentration increases, the crystalline UO{sub 2}(DBP){sub 2} shows molecular substitutions and an increase in amorphous content.« less

Multi-electrolyte-step anodic aluminum oxide method for the fabrication of self-organized nanochannel arrays

PubMed Central

2012-01-01

Nanochannel arrays were fabricated by the self-organized multi-electrolyte-step anodic aluminum oxide [AAO] method in this study. The anodization conditions used in the multi-electrolyte-step AAO method included a phosphoric acid solution as the electrolyte and an applied high voltage. There was a change in the phosphoric acid by the oxalic acid solution as the electrolyte and the applied low voltage. This method was used to produce self-organized nanochannel arrays with good regularity and circularity, meaning less power loss and processing time than with the multi-step AAO method. PMID:22333268

Morphological changes of porphine films on graphite by perchloric and phosphoric electrolytes. An electrochemical-AFM study

NASA Astrophysics Data System (ADS)

Yivlialin, Rossella; Penconi, Marta; Bussetti, Gianlorenzo; Biroli, Alessio Orbelli; Finazzi, Marco; Duò, Lamberto; Bossi, Alberto

2018-06-01

Organic molecules have been proposed as promising candidates for electrode protection in acidic electrolytes. The use of tetraphenyl-porphines (H2TPP) as graphite surface-protecting agents in sulphuric acid (H2SO4) is one of the newest. With the aim of unveiling the mechanism of such a protective effect, in this paper we test the stability of a H2TPP thin film immersed in perchloric and phosphoric acid solutions that differently interact with porphyrins. The protective role of H2TPP is tested in the electrochemical potential range where the pristine graphite undergoes an oxidation process that erodes the surface and eventually exfoliate the stratified crystal. The electrochemical analysis is performed in a three-electrode cell, while the surface morphology is monitored ex-situ and in-situ by atomic force microscopy. Electrospray mass analysis is also employed to investigate the presence of H2TPP fragments in the solution. We find that the organic film is not stable in perchloric solution, while it is stable and avoids graphite surface corrosion in phosphoric acid solution. These results provide a rationale for the role played by free-base porphines in graphite protection.

SEPARATION OF PLUTONIUM FROM AQUEOUS SOLUTIONS BY ION-EXCHANGE

DOEpatents

Schubert, J.

1958-06-01

A process is described for the separation of plutonium from an aqueous solution of a plutonium salt, which comprises adding to the solution an acid of the group consisting of sulfuric acid, phosphoric acid, and oxalic acid, and mixtures thereof to provide an acid concentration between 0.0001 and 1 M, contacting the resultant solution with a synthetic organic anion exchange resin, and separating the aqueous phase and the resin which contains the plutonium.

Effects of Y/Gd Ratio and Boron Excess on Vacuum Ultraviolet Characteristics and Morphology of (Y,Gd)BO3:Eu Phosphor Particles Prepared by Spray Pyrolysis

NASA Astrophysics Data System (ADS)

Koo, Hye Young; Jung, Dae Soo; Hong, Seung Kwon; Kang, Yun Chan; Jung, Kyeong Youl

2007-06-01

(Y1-xGdx)BO3:Eu (0≤ x≤ 1) phosphor particles were prepared by spray pyrolysis. The optimal amount of boric acid for the high photoluminescence intensity of there particles differed depending on the molar ratio of Y to Gd. With decreasing Y/Gd molar ratio, an increasing amount of excess boric acid was required. The difference in excess quantity of boric acid, which was demanded for the highest photoluminescence intensity according to the Y/Gd ratio, influenced the morphology and mean size of the (Y,Gd)BO3:Eu phosphor particles. The (Y1-xGdx)BO3:Eu (0≤ x≤ 1) phosphor particles had a regular morphology. The mean sizes of the GdBO3:Eu and YBO3:Eu phosphor particles were 1.4 and 1 μm, respectively. The high reactivity of boron and yttrium components produced YBO3:Eu phosphor particles with high photoluminescence intensities by spray pyrolysis using a spray solution with a stoichiometric amount of boric acid.

SEPARATION OF PLUTONIUM FROM URANIUM AND FISSION PRODUCTS

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

Boyd, G.E.; Adamson, A.W.; Schubert, J.

A chromatographic adsorption process is presented for the separation of plutonium from other fission products formed by the irradiation of uranium. The plutonium and the lighter element fission products are adsorbed on a sulfonated phenol-formaldehyde resin bed from a nitric acid solution containing the dissolved uranium. Successive washes of sulfuric, phosphoric, and nitric acids remove the bulk of the fission products, then an eluate of dilute phosphoric and nitric acids removes the remaining plutonium and fission products. The plutonium is selectively removed by passing this solution through zirconium phosphate, from which the plutonium is dissolved with nitric acid. This processmore » provides a convenient and efficient means for isolating plutonium.« less

Rare-earth leaching from Florida phosphate rock in wet-process phosphoric acid production

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

Liang, Haijun; Zhang, Patrick; Jin, Zhen

Phosphorite, or phosphate rock, is the most significant secondary rare-earth resource. It contains high amounts of phosphate-bearing minerals along with low contents of rare earth elements (REEs). In Florida, about 19 Mt of phosphate rock are mined annually and most are used to manufacture fertilizers using a wet process, in which sulfuric acid reacts with phosphates to produce phosphoric acid and phosphogypsum. In the wet process, REEs are also leached out into solution and eventually get lost in the leaching residue and phosphate fertilizer. Recovering REEs from Florida phosphate rock in the wet process will be beneficial to broadening rare-earthmore » availability, improving the quality of phosphoric acid product and protecting the environment. Here, this study focuses on the influences of wet-process operating conditions on REE leaching efficiency. The results indicate that REE leaching efficiency increases with phosphoric acid addition in the initial pulp. At a temperature of 75 °C, a stoichiometric ratio of sulfuric acid (H2 SO4 ) to calcium oxide (CaO) of 1.05 and a weight ratio of liquid to solid of 3.5, REE leaching efficiency reached a relatively high value of 52.82 percent. The trends of REE leaching efficiency were similar to those for phosphoric acid (P2O5 ). Extensive tests on the leaching residue showed that during leaching, about 90 percent of the REEs were released from the phosphate rock but only 52.82 percent ended up in the leaching solution. This phenomenon can be attributed to two factors: (1) the effect of phosphate ions (PO43-) in the solution, which caused REE ions to form REE phosphates and be precipitated into the leaching residue, and (2) the influence of large amounts of anions such as sulfate (SO42-), dihydrogen phosphate (H2 PO4-) and hydrogen phosphate (HPO42-) anions as well as the polar molecule H3 PO4 , which surrounded the REE cations and formed an ion atmosphere that prevented the PO43- from contacting and combining with REE cations. Finally, interaction of these two opposite effects determined the REE distribution between leaching solution and residue.« less

Rare-earth leaching from Florida phosphate rock in wet-process phosphoric acid production

DOE PAGES

Liang, Haijun; Zhang, Patrick; Jin, Zhen; ...

2017-08-01

Phosphorite, or phosphate rock, is the most significant secondary rare-earth resource. It contains high amounts of phosphate-bearing minerals along with low contents of rare earth elements (REEs). In Florida, about 19 Mt of phosphate rock are mined annually and most are used to manufacture fertilizers using a wet process, in which sulfuric acid reacts with phosphates to produce phosphoric acid and phosphogypsum. In the wet process, REEs are also leached out into solution and eventually get lost in the leaching residue and phosphate fertilizer. Recovering REEs from Florida phosphate rock in the wet process will be beneficial to broadening rare-earthmore » availability, improving the quality of phosphoric acid product and protecting the environment. Here, this study focuses on the influences of wet-process operating conditions on REE leaching efficiency. The results indicate that REE leaching efficiency increases with phosphoric acid addition in the initial pulp. At a temperature of 75 °C, a stoichiometric ratio of sulfuric acid (H2 SO4 ) to calcium oxide (CaO) of 1.05 and a weight ratio of liquid to solid of 3.5, REE leaching efficiency reached a relatively high value of 52.82 percent. The trends of REE leaching efficiency were similar to those for phosphoric acid (P2O5 ). Extensive tests on the leaching residue showed that during leaching, about 90 percent of the REEs were released from the phosphate rock but only 52.82 percent ended up in the leaching solution. This phenomenon can be attributed to two factors: (1) the effect of phosphate ions (PO43-) in the solution, which caused REE ions to form REE phosphates and be precipitated into the leaching residue, and (2) the influence of large amounts of anions such as sulfate (SO42-), dihydrogen phosphate (H2 PO4-) and hydrogen phosphate (HPO42-) anions as well as the polar molecule H3 PO4 , which surrounded the REE cations and formed an ion atmosphere that prevented the PO43- from contacting and combining with REE cations. Finally, interaction of these two opposite effects determined the REE distribution between leaching solution and residue.« less

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.

Method for the recovery of actinide elements from nuclear reactor waste

DOEpatents

Horwitz, E. Philip; Delphin, Walter H.; Mason, George W.

1979-01-01

A process for partitioning and recovering actinide values from acidic waste solutions resulting from reprocessing of irradiated nuclear fuels by adding hydroxylammonium nitrate and hydrazine to the waste solution to adjust the valence of the neptunium and plutonium values in the solution to the +4 oxidation state, thus forming a feed solution and contacting the feed solution with an extractant of dihexoxyethyl phosphoric acid in an organic diluent whereby the actinide values, most of the rare earth values and some fission product values are taken up by the extractant. Separation is achieved by contacting the loaded extractant with two aqueous strip solutions, a nitric acid solution to selectively strip the americium, curium and rare earth values and an oxalate solution of tetramethylammonium hydrogen oxalate and oxalic acid or trimethylammonium hydrogen oxalate to selectively strip the neptunium, plutonium and fission product values. Uranium values remain in the extractant and may be recovered with a phosphoric acid strip. The neptunium and plutonium values are recovered from the oxalate by adding sufficient nitric acid to destroy the complexing ability of the oxalate, forming a second feed, and contacting the second feed with a second extractant of tricaprylmethylammonium nitrate in an inert diluent whereby the neptunium and plutonium values are selectively extracted. The values are recovered from the extractant with formic acid.

Y2O3:Eu phosphor particles prepared by spray pyrolysis from a solution containing citric acid and polyethylene glycol

NASA Astrophysics Data System (ADS)

Roh, H. S.; Kang, Y. C.; Park, H. D.; Park, S. B.

Y2O3:Eu phosphor particles were prepared by large-scale spray pyrolysis. The morphological control of Y2O3:Eu particles in spray pyrolysis was attempted by adding polymeric precursors to the spray solution. The effect of composition and amount of polymeric precursors on the morphology, crystallinity and photoluminescence characteristics of Y2O3:Eu particles was investigated. Particles prepared from a solution containing polyethylene glycol (PEG) with an average molecular weight of 200 had a hollow structure, while those prepared from solutions containing adequate amounts of citric acid (CA) and PEG had a spherical shape, filled morphology and clean surfaces after post-treatment at high temperature. Y2O3:Eu particles prepared from an aqueous solution with no polymeric precursors had a hollow structure and rough surfaces after post-treatment. The phosphor particles prepared from solutions with inadequate amounts of CA and/or PEG also had hollow and/or fragmented structures. The particles prepared from the solution containing 0.3 M CA and 0.3 M PEG had the highest photoluminescence emission intensity, which was 56% higher than that of the particles prepared from aqueous solution without polymeric precursors.

Effect of anodization on the surface characteristics and electrochemical behaviour of zirconium in artificial saliva.

PubMed

Romonti, Daniela E; Gomez Sanchez, Andrea V; Milošev, Ingrid; Demetrescu, Ioana; Ceré, Silvia

2016-05-01

The paper is focused on elaboration of ZrO2 films on pure zirconium via anodizing in phosphoric acid with and without fluoride at constant potentials of 30 V and 60 V. The structure and composition of the films were investigated using scanning electronic microscopy, Raman spectroscopy and X-ray photoelectron spectroscopy. The composition of the oxides formed at both potentials can be identified as monoclinic ZrO2. In addition to Zr and O, the layers formed in phosphoric acid contain phosphorus originating from the phosphoric acid. When the phosphoric acid solution contains NaF, fluorine is also incorporated into the oxide layer. The oxides formed at a higher voltage have greater roughness than those formed at 30 V. Anodized samples exhibit smaller current densities during anodic polarization compared to the as-received zirconium covered with native oxide. Copyright © 2016 Elsevier B.V. All rights reserved.

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. Copyright © 2011 Mosby, Inc. All rights reserved.

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.

Phosphoric acid purification through different raw and activated clay materials (Southern Tunisia)

NASA Astrophysics Data System (ADS)

Trabelsi, Wafa; Tlili, Ali

2017-05-01

This study concerns the purification of Tunisian phosphoric acid produced by the Tunisian Chemical Group (TCG), using raw and activated clays materials from Southern Tunisia. The Gafsa basin clays samples (Jebel Hamadi (JHM); Jebel Stah (JS) and the El Hamma sample (Jebel Aïdoudi (JAD)) were activated with 3 M, HCl solution. Phosphoric acid purification was performed on raw and activated clays. Mineralogical characterisation was carried out using the X-ray powder diffraction method and infrared absorption spectroscopy. Textural changes between raw and activated clays were identified using SEM observations and specific surface analysis. Jebel Hamadi clays were almost dominated by smectite associated with kaolinite and illite traces, while Jebel Stah and Jebel Aïdoudi clays were composed of the association of smectite, illite and kaolinite. It is worth noting that the position of the smectite (001) reflection increased after the acidic activation in all studied samples, indicating the relaxation of the smectite structure along the c-axis. This was corroborated by the increasing specific surface area of the clay particles with the activation process. The specific surface area was close to 50 m2/g and 200 m2/g, for raw and activated materials, respectively. The maximum phosphoric acid purification was obtained by using activated clays with 3 N HCl for 4 h. This performance correlated with the maximum of the external specific surface area which generated strong acid sites. Furthermore, the best results of phosphoric acids purification from TCG were obtained at a specific consumption equivalent to 30 Kg of clay/ton of P2O5. These results showed that the best phosphoric acid purification was yielded by Jebel Aïdoudi clay. In all cases, the highest organic carbon reduction rates in the phosphoric acid after filtration were obtained at 90°C.

Investigation of Pu(IV)-acetohydroxamic acid complex by solvent extraction with di(2-ethylhexyl) phosphoric acid

NASA Astrophysics Data System (ADS)

Brown, M. Alex; Paulenova, Alena; Tkac, Peter

2010-03-01

The stability constant of the Pu(IV)-acetohydroxamic acid complex Pu(AHA)3+ at 1 M ionic strength (pH = 0) has been investigated by method of solvent extraction. Di(2-ethylhexyl) phosphoric acid (HDEHP) was used to extract Pu(IV) from perchloric and nitric acid media at various AHA concentrations. Distribution ratios over a range of ligand concentrations were used in conjunction with graphical methods to obtain logβ1 = 14.3 ± 0.03 in perchloric acid. The stability constant determined from solutions in nitric acid was excluded because of the uncertainty in plutonium speciation.

Effect of Silica Nanoparticles on the Photoluminescence Properties of BCNO Phosphor

NASA Astrophysics Data System (ADS)

Nuryadin, Bebeh W.; Faryuni, Irfana Diah; Iskandar, Ferry; Abdullah, Mikrajuddin; Khairurrijal, Khairurrijal

2011-12-01

Effect of additional silica nanoparticles on the photoluminescence (PL) performance of boron carbon oxy-nitride (BCNO) phosphor was investigated. As a precursor, boric acid and urea were used as boron and nitrogen sources, respectively. The carbon sources was polyethylene glycol (PEG) with average molecule weight 20000 g/mol.. Precursor solutions were prepared by mixing these raw materials in pure water, followed by stirring to achieve homogeneous solutions. In this precursor, silica nanoparticles were added at various mass ratio from 0 to 7 %wt in the solution. The precursors were then heated at 750 °C for 60 min in a ceramic crucible under atmospheric pressure. The photoluminescence (PL) spectrum that characterized by spectrophotometer showed a single, distinct, and broad emission band varied from blue to near red color, depend on the PEG, boric acid and urea ratio in the precursor. The addition of silica nanoparticles caused the increasing of PL intensity as well as the shifting of peak wavelength of PL spectrum. The peak shifting of PL was affected by the concentration of silica nanoparticles that added into the precursor. We believe that the BCNO-silica composite phosphor becomes a promising material for the phosphor conversion-based white light-emitting diodes.

Chemically modified maize cobs waste with enhanced adsorption properties upon methyl orange and arsenic.

PubMed

Elizalde-González, María P; Mattusch, J; Wennrich, R

2008-07-01

The surface chemistry of maize naturasorbent was altered in this work by the modifying agents: phosphoric acid and different amines (triethanolamine, diethylenetriamine and 1,4-diaminobutane). Removal of methyl orange (25 mg l(-1)) was <50% by maize corn cobs modified by phosphorylation and higher by the quaternized samples: 68% with the 1,4-diaminobutane and 73% with the diethylenetriamine modificators. Adsorption of arsenite by the samples modified with phosphoric acid/ammonia was 11 microg g(-1), which corresponds to 98% removal from a 550 microg As l(-1) solution for an adsorbent dose of 50 mg ml(-1). The samples modified by phosphoric acid/urea removed 0.4 microg g(-1) arsenate from a 300 mug As l(-1) solution. Adsorption of methyl orange, arsenite and arsenate was superior by the chemically modified maize cobs judged against the initial naturasorbent. For comparison, removal by the commercial anion exchanger was 100% for methyl orange, 45% (5 microg g(-1)) for arsenite and 99% (5 microg g(-1)) for arsenate.

21 CFR 163.112 - Breakfast cocoa.

Code of Federal Regulations, 2011 CFR

2011-04-01

... ingredients. Ammonium, potassium, or sodium bicarbonate, carbonate, or hydroxide, or magnesium carbonate or oxide, used as such, or in aqueous solution; (2) Neutralizing agents. Phosphoric acid, citric acid and L...

New Approach to Remove Metals from Chromated Copper Arsenate (CCA)-Treated Wood

Treesearch

Todd F. Shupe; Chung Y. Hse; Hui Pan

2012-01-01

Recovery of metals from chromated copper arsenate (CCA)-treated southern pine wood particles was investigated using binary acid solutions consisting of acetic, oxalic, and phosphoric acids in a microwave reactor. Formation of an insoluble copper oxalate complex in the binary solution containing oxalic acid was the major factor for low copper removal. Furthermore, the...

Comparison of microleakage on one composite etched with phosphoric acid or a combination of phosphoric and hydrofluoric acids and bonded with several different systems.

PubMed

Szep, Susanne; Langner, Nicole; Bayer, Silja; Börnichen, Diana; Schulz, Christoph; Gerhardt, Thomas; Schriever, Anette; Becker, Joachim; Heidemann, Detlef

2003-02-01

There are no data available on whether or to what extent hydrofluoric acid affects the marginal integrity of dentin-bonded composite restorations when it is used instead of phosphoric acid in the total-etch technique. This in vitro study examined the etching effects of phosphoric acid versus a combination of phosphoric and hydrofluoric acid by evaluation of microleakage in a composite restoration bonded with different dentin adhesive systems. Extracted teeth (n = 90) containing 2 class II preparations, mesial occlusal (MO) and distal occlusal (DO) standarized (cervical margins in dentin) were perfused with Ringer solution and etched in 1 of 2 ways: with phosphoric acid only or with phosphoric combined with hydrofluoric acid. Different dentin bonding agents were then applied (Etch & Prime 3.0, Optibond Solo, Prime & Bond NT, Scotchbond 1, Syntac Single Component, or Syntac Sprint; (n = 15 for each etching material)). The preparations were restored with a hybrid composite (Herculite XRV) and submitted to 5000 thermocycles (5 degrees C to 55 degrees C) to simulate the in vivo situation. Microleakage was assessed with 2% methylene blue diffusion for 24 hours. Dye penetration was calculated as a percentage of the total length of the gingival margins of the preparation with light microscopy at original magnification x 32. The results were analyzed with the Kruskal-Wallis multiple comparison z-value assay (alpha = .05). Differences in dye penetration were significant, both as a function of the dentin adhesive and the conditioning mode applied. In the specimen groups conditioned with phosphoric acid, Optibond Solo (54% +/- 44%) and Syntac Sprint (74% +/- 39%) demonstrated the lowest penetration values. Higher values were obtained for Prime & Bond NT (81% +/- 34%), Scotchbond 1 (83% +/- 31%), Etch & Prime 3.0 (85% +/- 33%), and Syntac Single Component (95% +/- 16%), with no significant differences (alpha=.05) between specimen groups. The best results were obtained for Syntac Sprint (24% +/- 26% dye penetration) after conditioning with a mixture of phosphoric and hydrofluoric acid. The least favorable result was obtained for Optibond Solo (65% +/- 31%). It was significantly different from Prime & Bond NT (76% +/- 37%), Scotchbond 1 (85% +/- 29%), and Etch & Prime 3.0 (88% +/- 24%). Syntac Single Component (75% +/- 32%) was significantly different from Syntac Sprint. Syntac Single Component and Syntac Sprint exhibited significantly better results when conditioned with a combination of phosphoric acid and hydrofluoric acid than with phosphoric acid only. Within the limitations of this in vitro study, total-etching water-based (Syntac Single Component) and acetone-based (Syntac Sprint) bonding agents with a combination of phosphoric acid and hydrofluoric acid led to significant reductions (alpha=.05) in dye penetration compared to phosphoric acid conditioning only. Ethanol-based dentin bonding agents (Etch & Prime 3.0, Optibond Solo, and Scotchbond 1) were not significantly influenced by the type of conditioner used.

Chemical-milling solution for invar alloy

NASA Technical Reports Server (NTRS)

Batiuk, W.

1980-01-01

Excellent surface finishes and tolerances are achieved using two formulations. Solution A gives finish of 3.17 micrometers after milling at 57 to 63 deg C. Constituents of A are: Hydrofluoric acid (70%), 5,8 oz/gal; nitric acid (40-42) degrees Baume), 40 oz/gal. Alternative solution gives 2.16 micrometer finish, and differs from A by addition of 7% phosphoric acid. Formulations eliminate channeling at root fillets, dishing, island formation, and overhangs.

Preparation and physical properties of (PVA)0.7(NaBr)0.3(H3PO4)xM solid acid membrane for phosphoric acid – Fuel cells

PubMed Central

Ahmad, F.; Sheha, E.

2012-01-01

A solid acid membranes based on poly (vinyl alcohol) (PVA), sodium bromide (NaBr) and phosphoric acid (H3PO4) were prepared by a solution casting method. The morphological, IR, electrical and optical properties of the (PVA)0.7(NaBr)0.3(H3PO4)xM solid acid membranes where x = 0.00, 0.85, 1.7, 3.4, 5.1 M were investigated. The variation of film morphology was examined by scanning electron microscopy (SEM) studies. FTIR spectroscopy has been used to characterize the structure of polymer and confirms the complexation of phosphoric acid with host polymeric matrix. The temperature dependent nature of ionic conductivity and the impedance of the polymer electrolytes were determined along with the associated activation energy. The ionic conductivity at room temperature was found to be strongly depends on the H3PO4 concentration which it has been achieved to be of the order 4.3 × 10−3 S/cm at ambient temperature. Optical measurements showed a decrease in optical band gap and an increase in band tail width with the increase of phosphoric acid. The data shows that the (PVA)0.7(NaBr)0.3(H3PO4)xM solid acid membrane is promising for intermediate temperature phosphoric acid fuel cell applications. PMID:25685413

Morphological Evaluation of the Adhesive/Enamel interfaces of Two-step Self-etching Adhesives and Multimode One-bottle Self-etching Adhesives.

PubMed

Sato, Takaaki; Takagaki, Tomohiro; Matsui, Naoko; Hamba, Hidenori; Sadr, Alireza; Nikaido, Toru; Tagami, Junji

To evaluate the acid-base resistant zone (ABRZ) at the adhesive/enamel interface of self-etching adhesives with or without prior phosphoric acid etching. Four adhesives were used in 8 groups: Clearfil SE Bond (SEB), Optibond XTR (XTR), Scotchbond Universal Adhesive (SBU), and Clearfil BOND SE ONE (ONE) without prior phosphoric-acid etching, and each adhesive with phosphoric acid etching for 10 s (P-SEB, P-XTR, P-SBU and P-ONE, respectively). After application of self-etching adhesives on ground enamel surfaces of human teeth, a flowable composite was placed. For observation of the acid-base resistant zone (ABRZ), the bonded interface was exposed to demineralizing solution (pH 4.5) for 4.5 h, followed by 5% NaOCl with ultrasonication for 20 min. After the acid-base challenge, morphological attributes of the interface were observed using SEM. ABRZ formation was confirmed in all groups. The funnel-shaped erosion beneath the interface was present in SBU and ONE, where nearly 10 to 15 μm of enamel was dissolved. With phosphoric acid etching, the ABRZs were obviously thicker compared with no phosphoric acid etching. Enamel beneath the bonding interface was more susceptible to acid dissolution in SBU and ONE. In the case of the one-bottle self-etching adhesives and universal adhesives that intrinsically have higher pH values, enamel etching should be recommended to improve the interfacial quality.

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.

Superlubricity behavior with phosphoric acid-water network induced by rubbing.

PubMed

Li, Jinjin; Zhang, Chenhui; Luo, Jianbin

2011-08-02

In present work, a superlubricity phenomenon of phosphoric acid (H(3)PO(4)) was found under ambient conditions. An ultralow friction coefficient of about 0.004 between glass/Si(3)N(4) and sapphire/sapphire tribopairs was obtained under the lubrication of a phosphoric acid aqueous solution (pH 1.5) at high contact pressure (the maximum pressure can reach about 1.65 GPa) after a running-in period of about 600 s. The experimental results indicate that the superlow friction state was very stable for more than 3 h. In such a state, solidlike films formed on the two sliding surfaces, which are hydrates of phosphoric acid with a hydrogen-bonded network according to the Raman spectrum. The superlubricity mechanism is mainly attributed to the hydrogen bond effect that forms a hydrated water layer with low shearing strength, and the dipole-dipole effects that form an interfacial Coulomb repulsion force also make some contributions to low friction. This work may help us to introduce a new approach to superlubricity and may lead to the wide application of superlubricity in future technological and biomedical areas.

Chemical treatment of low-grade uranium ores. Extraction of uranium from tricalcium phosphate; TRAITEMENT CHIMIQUE DES MINERAIS PAUVRES D'URANIUM. EXTRACTION DE L'URANIUM DU PHOSPHATE TRICALCIQUE (in French)

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

Mechelynck, Ph.

1958-07-15

After an examination of the different processes for the treatment of uranium minerals, it is concluded that the extraction of uranium by ion exchange is not applicable to hydrochloric acid solutions of phosphates. A sulfuric or phosphoric solution can be used. For solvent extraction of uranium, sulfuric or phosphoric solutions are the best, but hydrochloric solutions can be used. The cost of the solvents used would determine the cost of the operation. It is necessary, in the case of liquid-liquid extraction, to filter or decant the solution before extraction. (tr-auth)

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

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

Lassinantti Gualtieri, Magdalena, E-mail: magdalena.gualtieri@unimore.it; Romagnoli, Marcello; Pollastri, Simone

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 constructionmore » 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.« less

Deciphering the role and nature of phosphate species at the surface of stainless steel immersed in phosphoric acid solutions

NASA Astrophysics Data System (ADS)

Liascukiene, I.; Ben Salah, M.; Sabot, R.; Refait, Ph.; Dhouibi, L.; Méthivier, C.; Landoulsi, J.; Jeannin, M.

2018-03-01

We investigate the evolution of the surface of a highly alloyed stainless steel (Sanicro 28) upon immersion in aqueous phosphoric acid solutions. For this purpose, both short- (few hours) and long-term immersion (several days) were carried out. A detailed analysis of XPS spectra allowed a distinction to be made between oxygen originating from the organic adlayer (adventitious contamination), the passive oxide layer, and adsorbed phosphate species. By estimating the fraction of oxygen due to phosphate species (Oph), it was shown that the Oph/P molar concentration ratio was ranging from about 2 to 3. This suggests the presence of a polyphosphate layer at the stainless steel surface, as also supported by Raman analysis, which influence the electrochemical behavior of SS in the acidic media.

Chemical treatment of commercial reverse osmosis membranes for use in FO

EPA Science Inventory

Commercially available reverse osmosis (RO) membranes – SW30HR, BW30, and AG – were chemically treated for use in forward osmosis (FO). Nitric acid, phosphoric acid, sulfuric acid, ethanol, and ethanol–acid–water ternary solutions were employed for the treatment. All three membra...

METHOD OF APPLYING COPPER COATINGS TO URANIUM

DOEpatents

Gray, A.G.

1959-07-14

A method is presented for protecting metallic uranium, which comprises anodic etching of the uranium in an aqueous phosphoric acid solution containing chloride ions, cleaning the etched uranium in aqueous nitric acid solution, promptly electro-plating the cleaned uranium in a copper electro-plating bath, and then electro-plating thereupon lead, tin, zinc, cadmium, chromium or nickel from an aqueous electro-plating bath.

IRON COATED URANIUM AND ITS PRODUCTION

DOEpatents

Gray, A.G.

1960-03-15

A method of applying a protective coating to a metallic uranium article is given. The method comprises etching the surface of the article with an etchant solution containlng chloride ions, such as a solution of phosphoric acid and hydrochloric acid, cleaning the etched surface, electroplating iron thereon from a ferrous ammonium sulfate electroplating bath, and soldering an aluminum sheath to the resultant iron layer.

ECLSS Sustaining Compatibility Testing on Urine Processor Assembly Nonmetallic Materials for Reformulation of Pretreated Urine Solution

NASA Technical Reports Server (NTRS)

Wingard, C. D.

2015-01-01

On International Space Station (ISS), the Urine Processor Assembly (UPA) converts human urine and flush water into potable water. The urine is acid-pretreated primarily to control microbial growth. In recent years, the sulfuric acid (H2SO4) pretreatment was believed to be largely responsible for producing salt crystals capable of plugging filters in UPA components and significantly reducing the percentage of water recovery from urine. In 2012, ISS management decided to change the acid pretreatment for urine from sulfuric to phosphoric with the goal of eliminating or minimizing formation of salt crystals. In 2013-2014, as part of the qualification of the phosphoric acid (H3PO4) formulation, samples of 12 nonmetallic materials used in UPA components were immersed for up to one year in pretreated urine and brine solutions made with the new H3PO4 formulation. Dynamic mechanical analysis (DMA) was used to measure modulus (stiffness) of the immersed samples compared to virgin control samples. Such compatibility data obtained by DMA for the H3PO4-based solutions were compared to DMA data obtained for the H2SO4-based solutions in 2002-2003.

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.

Hydrofluosilicic acid as a cap and can etchant

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

Dixon, D.S.

1953-03-17

Aluminum caps and cans are thoroughly cleaned, before being used to can slugs, to insure wetting of the metal surfaces by molten AlSi in the canning pot. An acid bath is used, as part of the cleaning operations to remove surface oxide and other surface films from the metal. Two acid solutions are authorized in the standard operating procedure; a 20% phosphoric acid solution for etching both caps and cans, and a 1% hydrofluosilicic acid solution to be used for caps only. It is desired to determine the feasibility of using hydrofluosilicic acid exclusively as an etchant for both capsmore » and cans.« less

New tooth enamel from brushite crystals

NASA Technical Reports Server (NTRS)

Rubin, B.; Childress, J. D.

1974-01-01

Appropriate nutrient gel solution could be used to precipitate brushite, which becomes hydroxyapatite, mineral found in bones and teeth. Gel can be made from sodium metasilicate and phosphoric acid, or gelatin, or other organic materials that polymerize in presence of acid to get gelantinous medium.

Micro-electro-mechanical systems phosphoric acid fuel cell

DOEpatents

Sopchak, David A [Livermore, CA; Morse, Jeffrey D [Martinez, CA; Upadhye, Ravindra S [Pleasanton, CA; Kotovsky, Jack [Oakland, CA; Graff, Robert T [Modesto, CA

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.

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.

SEPARATION OF URANIUM FROM ZIRCONIUM AND NIOBIUM BY SOLVENT EXTRACTION

DOEpatents

Voiland, E.E.

1958-05-01

A process for separation of the uranium from zirconium and/or niobium values contained in 3 to 7M aqueous nitric acid solutions is described. This is accomplished by adding phosphoric acid anions to the nitric acid solution containing the uranium, zirconium, and/or niobium in an amount sufficient to make the solution 0.05 to 0.2M in phosphate ion and contacting the solution with an organic water-immiscible solvent such as MEK, whereby the uranyl values are taken up by the extract phase while the zirconium and niobium preferentially remain in the aqueous raffinate.

Metal etching composition

NASA Technical Reports Server (NTRS)

Otousa, Joseph E. (Inventor); Thomas, Clark S. (Inventor); Foster, Robert E. (Inventor)

1991-01-01

The present invention is directed to a chemical etching composition for etching metals or metallic alloys. The composition includes a solution of hydrochloric acid, phosphoric acid, ethylene glycol, and an oxidizing agent. The etching composition is particularly useful for etching metal surfaces in preparation for subsequent fluorescent penetrant inspection.

Acidic solvent extraction of gossypol from cottonseed meal

USDA-ARS?s Scientific Manuscript database

In order to expand the use of cottonseed meal in animal feeding, extraction of the meal gossypol was studied with acetic acetone- and ethanol-based solutions. Phosphoric acid was added to hydrolyze and release gossypol bound within the meal. Both solvent systems were effective at reducing gossypo...

Metal-phosphate binders

DOEpatents

Howe, Beth Ann [Lewistown, IL; Chaps-Cabrera, Jesus Guadalupe [Coahuila, MX

2009-05-12

A metal-phosphate binder is provided. The binder may include an aqueous phosphoric acid solution, a metal-cation donor including a metal other than aluminum, an aluminum-cation donor, and a non-carbohydrate electron donor.

Comparison of 2-Octanol and Tributyl Phosphate in Recovery of Tungsten from Sulfuric-Phosphoric Acid Leach Solution of Scheelite

NASA Astrophysics Data System (ADS)

Liao, Yulong; Zhao, Zhongwei

2018-04-01

Tungsten was recovered from sulfuric-phosphoric acid leach solution of scheelite using 2-octanol and tributyl phosphate (TBP). Approximately 76% of the tungsten and less than 6.2% of the iron were extracted when using 70% 2-octanol, showing good selectivity for tungsten over iron; the tungsten extraction could not be significantly enhanced using a three-stage countercurrent simulation test. Moreover, more than 99.2% of the W and 91.0% of the Fe were extracted when using 70% TBP, showing poor selectivity, but after pretreating the leach solution with iron powder, less than 5.5% of the Fe was extracted. The loaded phases were stripped using deionized water and ammonia solution. The maximum stripping rate of tungsten from loaded 2-octanol was 45.6% when using water, compared with only 13.1% from loaded TBP. Tungsten was efficiently stripped from loaded phases using ammonia solution without formation of Fe(OH)3 precipitate. Finally, a flow sheet for recovery of tungsten with TBP is proposed.

Synthesis of phosphonic acid silver-graphene oxide nanomaterials with photocatalytic activity through ultrasonic-assisted method.

PubMed

Li, Yongshen; Song, Yunna; Ma, Zheng; Niu, Shuai; Li, Jihui; Li, Ning

2018-06-01

In this article, phosphonic acid silver-graphene oxide nanomaterials (Nano-PAS-GO) was synthesized from silver nitrate (AgNO 3 ) solution and phosphoric graphene oxide (PGO) via the convenient ultrasonic-assisted method, and the structure and morphology were characterized, and the photocatalytic activity and recyclability were evaluated through photocatalyzing degradation of Rhodamin B (RhB) aqueous solution, and the possible photocatalytic mechanism was also discussed. Based on those, it was confirmed that Nano-PAS-GO has been synthesized from AgNO 3 solution and PGO colloidal suspension under ultrasonic-assisted condition, and Nano-PAS-GO has consisted of phosphoric acid silver nanoparticles and GO with 2D lattice (2D GO lattice) connected in the form of C-P bonds, and the photodegradation rate of Nano-PAS-GO for RhB aqueous solution has reached 93.99%, and Nano-PAS-GO has possessed the nicer recyclability when the photocatalytic time was 50 min. From those results, the strong and stable interface . between PAS nanoparticles and 2D GO lattice connected in the form of the covalent bonds has effectively inhibited the occurrence of the photocorrosion phenomenon. Copyright © 2018 Elsevier B.V. All rights reserved.

Cation-enhanced capillary electrophoresis separation of atropoisomer anions.

PubMed

Na, Yun-Cheol; Berthod, Alain; Armstrong, Daniel W

2015-12-01

CE was used to study the separation of the atropoisomers of four phosphoric acids and two sulfonic acids and the enantiomers of two phosphoric acids. All solutes are in their anionic forms in aqueous electrolytes. The chiral additives were two hydroxypropyl cyclodextrins (CDs) and cyclofructan 6 (CF6). The CDs were able to separate four solutes and the CF6 additive could separate only one: 1,1'-binaphthyl-2,2'-diyl hydrogenphosphate (BHP). Since CF6 is able to bind with cations, nitrate of alkaline metals, Ba(2+) , and Pb(2+) were added, greatly improving the BHP separation at the expense of longer migration times. There seems to be a link between CF6-cation-binding constants and BHP resolution factors. Cation additions were also performed with CD selectors that are less prone to form complexes with cations. Significant improvements of enantiomer or atropoisomer separations were observed also associated with longer migration times. It is speculated that the anionic solutes associate with the added cations forming larger entities better differentiated by CDs. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

AGARD Corrosion Handbook. Volume 1. Aircraft Corrosion: Causes and Case Histories

DTIC Science & Technology

1985-07-01

Anodic coatings can be formed in chromic acid, sulphuric acid, phosphoric acid or oxalic acid solutions. Chromic acid anodizing is widely used with...and consists of a thin non-porous barrier layer next to the metal with a porous outer layer that can be sealed by hydrothermal treatment in steam...anaerobic) or an oxidative (aerobic) mechanism. Various organic acids such as citric acid, oxalic acid, gluconic acid, dodecanoic acid, etc., which may be

Ultrastructural observation of the acid-base resistant zone of all-in-one adhesives using three different acid-base challenges.

PubMed

Tsujimoto, Miho; Nikaido, Toru; Inoue, Go; Sadr, Alireza; Tagami, Junji

2010-11-01

The aim of this study was to analyze the ultrastructure of the dentin-adhesive interface using two all-in-one adhesive systems (Clearfil Tri-S Bond, TB; Tokuyama Bond Force, BF) after different acid-base challenges. Three solutions were used as acidic solutions for the acid-base challenges: a demineralizing solution (DS), a phosphoric acid solution (PA), and a hydrochloric acid solution (HCl). After the acid-base challenges, the bonded interfaces were examined by scanning electron microscopy. Thickness of the acid-base resistant zone (ABRZ) created in PA and HCl was thinner than in DS for both adhesive systems. For BF adhesive, an eroded area was observed beneath the ABRZ after immersion in PA and HCl, but not in DS. Conversely for TB adhesive, the eroded area was observed only after immersion in PA. In conclusion, although the ABRZ was observed for both all-in-one adhesive systems, its morphological features were influenced by the ingredients of both the adhesive material and acidic solution.

Bioactive Surface Modification of Hydroxyapatite

PubMed Central

Okazaki, Yohei; Hiasa, Kyou; Yasuda, Keisuke; Nogami, Keisuke; Mizumachi, Wataru; Hirata, Isao

2013-01-01

The purpose of this study was to establish an acid-etching procedure for altering the Ca/P ratio of the nanostructured surface of hydroxyapatite (HAP) by using surface chemical and morphological analyses (XPS, XRD, SEM, surface roughness, and wettability) and to evaluate the in vitro response of osteoblast-like cells (MC3T3-E1 cells) to the modified surfaces. This study utilized HAP and HAP treated with 10%, 20%, 30%, 40%, 50%, or 60% phosphoric acid solution for 10 minutes at 25°C, followed by rinsing 3 times with ultrapure water. The 30% phosphoric acid etching process that provided a Ca/P ratio of 1.50, without destruction of the grain boundary of HAP, was selected as a surface-modification procedure. Additionally, HAP treated by the 30% phosphoric acid etching process was stored under dry conditions at 25°C for 12 hours, and the Ca/P ratio approximated to 1.00 accidentally. The initial adhesion, proliferation, and differentiation (alkaline phosphatase (ALP) activity and relative mRNA level for ALP) of MC3T3-E1 cells on the modified surfaces were significantly promoted (P < 0.05 and 0.01). These findings show that the 30% phosphoric acid etching process for the nanostructured HAP surface can alter the Ca/P ratio effectively and may accelerate the initial adhesion, proliferation, and differentiation of MC3T3-E1 cells. PMID:23862150

Ultrafast Scavenging of the Precursor of H(•) Atom, (e(-), H3O(+)), in Aqueous Solutions.

PubMed

Balcerzyk, Anna; Schmidhammer, Uli; Wang, Furong; de la Lande, Aurélien; Mostafavi, Mehran

2016-09-01

Picosecond pulse radiolysis measurements have been performed in several highly concentrated HClO4 and H3PO4 aqueous solutions containing silver ions at different concentrations. Silver ion reduction is used to unravel the ultrafast reduction reactions observed at the end of a 7 ps electron pulse. Solvated electrons and silver atoms are observed by the pulse (electron beam)-probe (supercontinuum light) method. In highly acidic solutions, ultrafast reduction of silver ions is observed, a finding that is not compatible with a reaction between the H(•) atom and silver ions, which is known to be thermally activated. In addition, silver ion reduction is found to be even more efficient in phosphoric acid solution than that in neutral solution. In the acidic solutions investigated here, the species responsible for the reduction of silver atoms is considered to be the precursor of the H(•) atom. This precursor, denoted (e(-), H3O(+)), is a pair constituting an electron (not fully solvated) and H3O(+). Its structure differs from that of the pair of a solvated electron and a hydronium ion (es(-), H3O(+)), which absorbs in the visible region. The (e(-), H3O(+)) pair , called the pre-H(•) atom here, undergoes ultrafast electron transfer and can, like the presolvated electron, reduce silver ions much faster than the H(•) atom. Moreover, it is found that with the same concentration of H3O(+) the reduction reaction is favored in the phosphoric acid solution compared to that in the perchloric acid solution because of the less-efficient electron solvation process. The kinetics show that among the three reducing species, (e(-), H3O(+)), (es(-), H3O(+)), and H(•) atom, the first one is the most efficient.

Catalyst evaluation for oxygen reduction reaction in concentrated phosphoric acid at elevated temperatures

NASA Astrophysics Data System (ADS)

Hu, Yang; Jiang, Yiliang; Jensen, Jens Oluf; Cleemann, Lars N.; Li, Qingfeng

2018-01-01

Phosphoric acid is the common electrolyte for high-temperature polymer electrolyte fuel cells (HT-PEMFCs) that have advantages such as enhanced CO tolerance and simplified heat and water management. The currently used rotating disk electrode technique is limited to tests in dilute solutions at low temperatures and hence is not suitable for catalyst evaluation for HT-PEMFCs. In this study, we have designed and constructed a half-cell setup to measure the intrinsic activities of catalysts towards the oxygen reduction reaction (ORR) in conditions close to HT-PEMFC cathodes. By optimization of the hydrophobic characteristics of electrodes and the catalyst layer thickness, ORR activities of typical Pt/C catalysts are successfully measured in concentrated phosphoric acid at temperatures above 100 °C. In terms of mass-specific activities, the catalyst exhibits about two times higher activity in the half-cell electrode than that observed in fuel cells, indicating the feasibility of the technique as well as the potential for further improvement of fuel cell electrode performance.

Fourier transform infrared characterization of the acidic phosphoric extractant system containing lanthanide

NASA Astrophysics Data System (ADS)

Shen, Y.-H.; Yao, S.-K.; Wang, D.-J.; Zhou, Weijin; Li, Ying Xue; Peng, Q.; Wu, JinGuang; Xu, Guang-Xian

1994-01-01

The aggregation states and FTIR spectra of the extractive organic phases of saponified HDEHP [di(2-ethylhexyl) phosphoric acid] (1). DMHPA [di(1-methylheptyl) phosphoric acid] (2) and (HDEHP + DMHPA) (3) containing lanthanides were studied, respectively. Transparent solution formed in system (1) while transparent gel formed in system (2) when the loading of lanthanides was more than 50%. The aggregation state of system (3) depends on the molar ratio of HDEHP:DMHPA and the loading percentage of lanthanide. From their FTIR spectra, it can be seen that the P equals O band of gel split into 1164, 1199, and 1232 cm-1, and the P-O-C band split into 1015, 1076, and 1083 cm-1 as well. The results suggested that the aggregation state of lanthanide complex changes considerably in the three systems, and multiple coordination states of p equals o with lanthanide result in the band split. Multiple interactions between P equals O, P-O-C and lanthanide ions form 3-D network in the gel.

Thin wire pointing method

NASA Technical Reports Server (NTRS)

Green, G.; Mattauch, R. J. (Inventor)

1983-01-01

A method is described for forming sharp tips on thin wires, in particular phosphor bronze wires of diameters such as one-thousandth inch used to contact micron size Schottky barrier diodes, which enables close control of tip shape and which avoids the use of highly toxic solutions. The method includes dipping an end of a phosphor bronze wire into a dilute solution of sulfamic acid and applying a current through the wire to electrochemically etch it. The humidity in the room is controlled to a level of less than 50%, and the voltage applied between the wire and another electrode in the solutions is a half wave rectified voltage. The current through the wire is monitored, and the process is stopped when the current falls to a predetermined low level.

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.

Color stable manganese-doped phosphors

DOEpatents

Lyons, Robert Joseph [Burnt Hills, NY; Setlur, Anant Achyut [Niskayuna, NY; Deshpande, Anirudha Rajendra [Twinsburg, OH; Grigorov, Ljudmil Slavchev [Sofia, BG

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.

Acids with an equivalent taste lead to different erosion of human dental enamel.

PubMed

Beyer, Markus; Reichert, Jörg; Bossert, Jörg; Sigusch, Bernd W; Watts, David C; Jandt, Klaus D

2011-10-01

The consumption of acidic soft drinks may lead to demineralization and softening of human dental enamel, known as dental erosion. The aims of this in vitro study were to determine: (i) if different acids with a similar sensorial acidic taste lead to different hardness loss of enamel and (ii) if the fruit acids tartaric, malic, lactic or ascorbic acid lead to less hardness loss of enamel than citric or phosphoric acid when their concentration in solution is based on an equivalent sensorial acidic taste. Enamel samples of non-erupted human third molars were treated with acidic solutions of tartaric (TA), malic (MA), lactic (LA), ascorbic (AA), phosphoric (PA) and citric (CA) acids with a concentration that gave an equivalent sensorial acidic taste. The acidic solutions were characterized by pH value and titratable acidity. Atomic force microscopy (AFM) based nanoindentation was used to study the nano mechanical properties and scanning electron microscopy (SEM) was used to study the morphology of the treated enamel samples and the untreated control areas, respectively. The investigated acids fell into two groups. The nano hardnesses of MA, TA and CA treated enamel samples (group I) were statistically significantly greater (p<0.05) than the nano hardnesses of PA, AA and LA treated enamel samples (group II). Within each group the nano hardness was not statistically significantly different (p>0.05). The SEM micrographs showed different etch prism morphologies depending on the acid used. In vitro, the acids investigated led to different erosion effects on human dental enamel, despite their equivalent sensorial acidic taste. This has not been reported previously. Copyright © 2011 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

A Volumetric Method for Titrimetric Analysis of Hydrogen Peroxide

DTIC Science & Technology

1985-05-06

fairly satisfactory indicator. Sulfuric acid solutions of cerium are stable over long periods of time, unlike the less stable nitric and hydrochloric acid ...Fisher number D141-5. 5. Sulfuric acid , concentrated (95-98 percent). For example, Fisher number A 300-212. 6. O-Phosphoric acid , 85 percent:. For example...Fisher number A 242-500. 7. 5 N sulfuric acid (Reference 11): Slowly pour 75 mL of concentrated sulfuric acid (95-98 percent) into approximately 200

Complexity in Acid-Base Titrations: Multimer Formation Between Phosphoric Acids and Imines.

PubMed

Malm, Christian; Kim, Heejae; Wagner, Manfred; Hunger, Johannes

2017-08-10

Solutions of Brønsted acids with bases in aprotic solvents are not only common model systems to study the fundamentals of proton transfer pathways but are also highly relevant to Brønsted acid catalysis. Despite their importance the light nature of the proton makes characterization of acid-base aggregates challenging. Here, we track such acid-base interactions over a broad range of relative compositions between diphenyl phosphoric acid and the base quinaldine in dichloromethane, by using a combination of dielectric relaxation and NMR spectroscopy. In contrast to what one would expect for an acid-base titration, we find strong deviations from quantitative proton transfer from the acid to the base. Even for an excess of the base, multimers consisting of one base and at least two acid molecules are formed, in addition to the occurrence of proton transfer from the acid to the base and simultaneous formation of ion pairs. For equimolar mixtures such multimers constitute about one third of all intermolecular aggregates. Quantitative analysis of our results shows that the acid-base association constant is only around six times larger than that for the acid binding to an acid-base dimer, that is, to an already protonated base. Our findings have implications for the interpretation of previous studies of reactive intermediates in organocatalysis and provide a rationale for previously observed nonlinear effects in phosphoric acid catalysis. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

[Application of solid-phase extraction column for determination of matrine and oxymatrine in Sophora flavescens].

PubMed

Yang, Xia; Guo, Bao-Lin; Hu, Hong-Yu; Huang, Wen-Hua; Qiao, He-Ping; Fan, Sheng-Ci; Guan, Zha-Gen

2013-09-01

A Cleanert Alumina-N-SPE column (0.5 g/6 mL) chromatograpy with 5 mL of chloroform-methanol (7: 3) as eluent, instead of aluminum oxide column (100-200 mesh, 5 g, 1 cm) chromatograpy eluted successively with chloroform and the chloroform-methanol (7:3) (20 mL each), was applied to enrich matrine and oxymatrine in Sophora flavescens. Also, the optimization of the HPLC determination conditions with acetonitrile-ethanol absolute-3% phosphoric acid solution (84: 6: 10) as mobile phase, instead of acetonitrile-ethanol absolute -3% Phosphoric acid solution (80: 10: 10) recorded in Chinese Pharmacopoeia 2010 Edition, was more suitable for determination of matrine and oxymatrine in S. flavescens. This method has advantage of reducing sample handling time and solvent volume and increasing the accuracy and feasibility, which can simplify the procedure for determination of matrine and oxymatrine in S. flavescens.

40 CFR 63.600 - Applicability.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Standards for Hazardous Air Pollutants From Phosphoric Acid Manufacturing Plants § 63.600 Applicability. (a... apply to the owner or operator of each phosphoric acid manufacturing plant. (b) The requirements of this... affected sources at a phosphoric acid manufacturing plant: (1) Each wet-process phosphoric acid process...

40 CFR 63.600 - Applicability.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Standards for Hazardous Air Pollutants From Phosphoric Acid Manufacturing Plants § 63.600 Applicability. (a... apply to the owner or operator of each phosphoric acid manufacturing plant. (b) The requirements of this... affected sources at a phosphoric acid manufacturing plant: (1) Each wet-process phosphoric acid process...

STRONTIUM PRECIPITATION

DOEpatents

McKenzie, T.R.

1960-09-13

A process is given for improving the precipitation of strontium from an aqueous phosphoric-acid-containing solution with nickel or cobalt ferrocyanide by simultaneously precipitating strontium or calcium phosphate. This is accomplished by adding to the ferrocyanide-containing solution calcium or strontium nitrate in a quantity to yield a concentration of from 0.004 to 0.03 and adjusting the pH of the solution to a value of above 8.

Complexity in Acid–Base Titrations: Multimer Formation Between Phosphoric Acids and Imines

PubMed Central

Malm, Christian; Kim, Heejae; Wagner, Manfred

2017-01-01

Abstract Solutions of Brønsted acids with bases in aprotic solvents are not only common model systems to study the fundamentals of proton transfer pathways but are also highly relevant to Brønsted acid catalysis. Despite their importance the light nature of the proton makes characterization of acid–base aggregates challenging. Here, we track such acid–base interactions over a broad range of relative compositions between diphenyl phosphoric acid and the base quinaldine in dichloromethane, by using a combination of dielectric relaxation and NMR spectroscopy. In contrast to what one would expect for an acid–base titration, we find strong deviations from quantitative proton transfer from the acid to the base. Even for an excess of the base, multimers consisting of one base and at least two acid molecules are formed, in addition to the occurrence of proton transfer from the acid to the base and simultaneous formation of ion pairs. For equimolar mixtures such multimers constitute about one third of all intermolecular aggregates. Quantitative analysis of our results shows that the acid‐base association constant is only around six times larger than that for the acid binding to an acid‐base dimer, that is, to an already protonated base. Our findings have implications for the interpretation of previous studies of reactive intermediates in organocatalysis and provide a rationale for previously observed nonlinear effects in phosphoric acid catalysis. PMID:28597513

URANIUM RECOVERY PROCESS

DOEpatents

Hyman, H.H.; Dreher, J.L.

1959-07-01

The recovery of uranium from the acidic aqueous metal waste solutions resulting from the bismuth phosphate carrier precipitation of plutonium from solutions of neutron irradiated uranium is described. The waste solutions consist of phosphoric acid, sulfuric acid, and uranium as a uranyl salt, together with salts of the fission products normally associated with neutron irradiated uranium. Generally, the process of the invention involves the partial neutralization of the waste solution with sodium hydroxide, followed by conversion of the solution to a pH 11 by mixing therewith sufficient sodium carbonate. The resultant carbonate-complexed waste is contacted with a titanated silica gel and the adsorbent separated from the aqueous medium. The aqueous solution is then mixed with sufficient acetic acid to bring the pH of the aqueous medium to between 4 and 5, whereby sodium uranyl acetate is precipitated. The precipitate is dissolved in nitric acid and the resulting solution preferably provided with salting out agents. Uranyl nitrate is recovered from the solution by extraction with an ether such as diethyl ether.

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... prescribed conditions: (a) For the purpose of this section, partial phosphoric acid esters of polyester...

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 with...

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 significant...

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. 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 section...

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 section...

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 section...

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. 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 section...

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 with...

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 with...

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 with...

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 new...

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 new...

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. 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 section...

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 is...

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 generally...

Why do proton conducting polybenzimidazole phosphoric acid membranes perform well in high-temperature PEM fuel cells?

PubMed

Melchior, Jan-Patrick; Majer, Günter; Kreuer, Klaus-Dieter

2016-12-21

Transport properties and hydration behavior of phosphoric acid/(benz)imidazole mixtures are investigated by diverse NMR techniques, thermogravimetric analysis (TGA) and conductivity measurements. The monomeric systems can serve as models for phosphoric acid/poly-benzimidazole membranes which are known for their exceptional performance in high temperature PEM fuel cells. 1 H- and 31 P-NMR data show benzimidazole acting as a strong Brønsted base with respect to neat phosphoric acid. Since benzimidazole's nitrogens are fully protonated with a low rate for proton exchange with phosphate species, proton diffusion and conduction processes must take place within the hydrogen bond network of phosphoric acid only. The proton exchange dynamics between phosphate and benzimidazole species pass through the intermediate exchange regime (with respect to NMR line separations) with exchange times being close to typical diffusion times chosen in PFG-NMR diffusion measurements (ms regime). The resulting effects, as described by the Kärger equation, are included into the evaluation of PFG-NMR data for obtaining precise proton diffusion coefficients. The highly reduced proton diffusion coefficient within the phosphoric acid part of the model systems compared to neat phosphoric acid is suggested to be the immediate consequence of proton subtraction from phosphoric acid. This reduces hydrogen bond network frustration (imbalance of the number of proton donors and acceptors) and therefore also the rate of structural proton diffusion, phosphoric acid's acidity and hygroscopicity. Reduced water uptake, shown by TGA, goes along with reduced electroosmotic water drag which is suggested to be the reason for PBI-phosphoric acid membranes performing better in fuel cells than other phosphoric-acid-containing electrolytes with higher protonic conductivity.

Measurement and modeling of density and viscosity of n-octanol-kerosene-phosphoric acid solutions in a temperature range 293.15-333.15 K

NASA Astrophysics Data System (ADS)

Ye, Changwen; Pei, Xiangjun; Liu, J. C.

2016-12-01

Densities and viscosities have been measured for the n-octanol + aviation kerosene (AK) + phosphoric acid (H3PO4) system with the mass fraction of H3PO4 in the range from w = 0 to 0.26 and in the temperature of 293.15-333.15 K. According to the experimental data, the measured viscosities were found well correlated with the temperature and mass fraction of H3PO4, which were fitted to regression equations. The result shows that the dilution effect of AK is obvious under the same temperature and mass fraction of H3PO4.

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 significant new uses subject to reporting. (1) The chemical substance identified as phosphoric acid, tin (2...

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 significant new uses subject to reporting. (1) The chemical substance identified as phosphoric acid, tin (2...

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 significant new uses subject to reporting. (1) The chemical substance identified as phosphoric acid, tin (2...

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 significant new uses subject to reporting. (1) The chemical substance identified as phosphoric acid, tin (2...

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 significant new uses subject to reporting. (1) The chemical substance identified as phosphoric acid, tin (2...

The effects of boric acid and phosphoric acid on the compressive strength of glass-ionomer cements.

PubMed

Prentice, Leon H; Tyas, Martin J; Burrow, Michael F

2006-01-01

Both boric acid (H3BO3) and phosphoric acid (H3PO4) are components of dental cements, commonly incorporated into glass (as ingredients in the melt) and occasionally added to the powder or liquid components. This study investigated the effect of boric acid addition to an experimental glass-ionomer powder and the effect of phosphoric acid addition to a glass-ionomer liquid on the 24-h compressive strength. Boric acid powder was added in various concentrations to an experimental glass-ionomer powder and, separately, phosphoric acid was added to an experimental glass-ionomer liquid. Powders and liquids were dosed into capsules at various powder:liquid ratios and cements thus formed were assessed for 24-h compressive strength. Incorporation of boric acid in glass-ionomer powder resulted in a pronounced decrease (p < 0.05 at 1% boric acid) in compressive strength. Addition of phosphoric acid produced initially stronger cements (up to 13% increase at 1% phosphoric acid) before also declining. The incorporation of less than 2% w/w phosphoric acid in glass-ionomer liquids may improve cement strengths without compromising clinical usefulness. The incorporation of boric acid in glass-ionomer cements is contraindicated.

ION EXCHANGE PROCESS FOR THE RECOVERY AND PURIFICATION OF MATERIALS

DOEpatents

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

1958-04-15

A process for the recovery of certain metallic ions from aqueous solutions by ion exchange techniques is described. It is applicable to elements such as vanadium, chromium, nnanganese, and the like, which are capable of forming lower valent cations soluble in aqueous solutions and which also form ldgher valent anions soluble in aqueous acidic solutions. For example, small amounts of vanadium occurring in phosphoric acid prepared from phosphate rock may be recovered by reducing the vanadium to a trivalent cation adsorbing; the vanadium in a cationic exchange resin, then treating the resin with a suitable oxidizing agent to convert the adsorbed vanadium to a higher valent state, and finally eluting; the vanadium as an anion from the resin by means of an aqueous acidic solution.

Optimization of preparation of activated carbon from cotton stalk by microwave assisted phosphoric acid-chemical activation.

PubMed

Deng, Hui; Zhang, Genlin; Xu, Xiaolin; Tao, Guanghui; Dai, Jiulei

2010-10-15

The preparation of activated carbon (AC) from cotton stalk was investigated in this paper. Orthogonal array experimental design method was used to optimize the preparation of AC using microwave assisted phosphoric acid. Optimized parameters were radiation power of 400 W, radiation time of 8 min, concentration of phosphoric acid of 50% by volume and impregnation time of 20 h, respectively. The surface characteristics of the AC prepared under optimized condition were examined by pore structure analysis, scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR). Pore structure analysis shows that mecropores constitute more of the porosity of the prepared AC. Compared to cotton stalk, different functionalities and morphology on the carbon surfaces were formed in the prepared process. The adsorption capacity of the AC was also investigated by removing methylene blue (MB) in aqueous solution. The equilibrium data of the adsorption was well fitted to the Langmuir isotherm. The maximum adsorption capacity of MB on the prepared AC is 245.70 mg/g. The adsorption process follows the pseudo-second-order kinetic model. 2010 Elsevier B.V. All rights reserved.

Extraction of manganese by alkyl monocarboxylic acid in a mixed extractant from a leaching solution of spent lithium-ion battery ternary cathodic material

NASA Astrophysics Data System (ADS)

Joo, Sung-Ho; Shin, Dongju; Oh, ChangHyun; Wang, Jei-Pil; Shin, Shun Myung

2016-02-01

We investigate the separation of manganese by an antagonistic effect from a leaching solution of ternary cathodic material of spent lithium-ion batteries that contain 11,400 mg L-1 Co, 11,700 mg L-1 Mn, 12,200 mg L-1 Ni, and 5300 mg L-1 Li using a mixture of alkyl monocarboxylic acid and di-(2-ethylhexyl)phosphoric acid extractants. pH isotherm, distribution coefficient, separation factor, McCabe-Thiele diagram, selective scrubbing, and countercurrent extraction tests are carried out to prove an antagonistic effect and to recover manganese using alkyl monocarboxylic in the mixed extractant. Slope analysis is used to determine the extraction mechanism between a mixture of extractants and valuable metals. An increasing concentration of alkyl monocarboxylic acid in the mixture of extractants results in a decrease in distribution coefficient of cobalt and manganese, however, the separation factor value (β(Mn/Co)) increases at pH 4.5. This is caused by slope analysis where alkyl monocarboxylic acid disrupts the extraction mechanism between di-(2-ethylhexyl)phosphoric acid and cobalt. Finally, continuous countercurrent extraction in a mini-plant test demonstrate the feasibility of manganese recovery from cobalt, nickel, and lithium.

Thermoelectrochemical system and method

DOEpatents

Ludwig, F.A.; Townsend, C.W.; Eliash, B.M.

1995-11-28

A thermal electrochemical system is described in which an electrical current is generated between a cathode immersed in a concentrated aqueous solution of phosphoric acid and an anode immersed in a molten salt solution of ammonium phosphate and monohydric ammonium phosphate. Reactants consumed at the electrodes during the electrochemical reaction are thermochemically regenerated and recycled to the electrodes to provide continuous operation of the system. 5 figs.

Alternate Spray-coating for the Direct Fabrication of Hydroxyapatite Films without Crystal Growth Step in Solution.

PubMed

Watanabe, Satoshi; Kashiwagi, Rei; Matsumoto, Mutsuyoshi

2017-03-01

We discuss an alternate spray-coating technique for the direct fabrication of hydroxyapatite films using metal masks, suction-type spray nozzles and two calcification solutions of calcium hydroxide and phosphoric acid aqueous solutions. Hydroxyapatite films were formed only on the hydrophobic surface of the substrates. Scanning electron microscopy and energy dispersive X-ray spectroscopy showed that the spray-coated films consisted of hydroxyapatite nanoparticles. The Ca/P ratio was estimated to be about 1.26. X-ray diffraction patterns of the spray-coated films almost coincided with those of the hydroxyapatite powders, showing that the spray-coated films consisted of hydroxyapatite nanoparticles. Dot arrays of hydroxyapatite films at a diameter of 100 μm were formed by tuning the concentrations of calcium hydroxide and phosphoric acid aqueous solutions. This technique allows for the direct fabrication of the hydroxyapatite films without crystal growth process in hydroxyapatite precursors, the scaffolds of crystal growth such as biocompatibility SiO 2 -CaO glasses, or electrophoresis processes. By using this technique, large-area ceramic films with biocompatibility will be micropatterned with minimized material consumption, short fabrication time, and reduced equipment investments.

21 CFR 582.1073 - Phosphoric acid.

Code of Federal Regulations, 2010 CFR

2010-04-01

... Additives § 582.1073 Phosphoric acid. (a) Product. Phosphoric acid. (b) Conditions of use. This substance is generally recognized as safe when used in accordance with good manufacturing or feeding practice. ...

21 CFR 582.1073 - Phosphoric acid.

Code of Federal Regulations, 2014 CFR

2014-04-01

... Additives § 582.1073 Phosphoric acid. (a) Product. Phosphoric acid. (b) Conditions of use. This substance is generally recognized as safe when used in accordance with good manufacturing or feeding practice. ...

21 CFR 582.1073 - Phosphoric acid.

Code of Federal Regulations, 2011 CFR

2011-04-01

... Additives § 582.1073 Phosphoric acid. (a) Product. Phosphoric acid. (b) Conditions of use. This substance is generally recognized as safe when used in accordance with good manufacturing or feeding practice. ...

21 CFR 582.1073 - Phosphoric acid.

Code of Federal Regulations, 2012 CFR

2012-04-01

... Additives § 582.1073 Phosphoric acid. (a) Product. Phosphoric acid. (b) Conditions of use. This substance is generally recognized as safe when used in accordance with good manufacturing or feeding practice. ...

21 CFR 582.1073 - Phosphoric acid.

Code of Federal Regulations, 2013 CFR

2013-04-01

... Additives § 582.1073 Phosphoric acid. (a) Product. Phosphoric acid. (b) Conditions of use. This substance is generally recognized as safe when used in accordance with good manufacturing or feeding practice. ...

SEPARATION OF EUROPIUM FROM OTHER LANTHANIDE RAE EARTHS BY SOLVENT EXTRACTION

DOEpatents

Peppard, D.F.; Horwitz, E.P.; Mason, G.W.

1963-02-12

This patent deals with a process of separating europium from other lanthanides present in aqueous hydrochloric or sulfuric acid solutions. The europium is selectively reduced to the divalent state with a divalent chromium salt formed in situ from chromium(III) salt plus zinc amalgam. The other trivalent lanthanides are then extracted away from the divalent europium with a nitrogen-flushed phosphoric acid ester or a phosphonic acid ester. (AEC)

Development of Novel Decontamination Techniques for Chemical Agents (GB, VX, HD) Contaminated Facilities. Phase 1. Identification and Evaluation of Novel Decontamination Concepts. Volume 2

DTIC Science & Technology

1983-02-01

Phosphoric, citric or other acids may be used as coupling agent/solvents in the cleaning tank. Decontamination solutions may also be used. Ultrasonics may be...111-54 "THERMAL DECOMPOSITION USING CO2 LASER . . . . . . . . . . . . . . 111-63 >’HYDROBLASTING. III-70 (-7, ACID ETCH/ NUTRALIZATION...111-192 NITRIC ACID . . .*. . . . .\\. . . . . . . . . . . . . . . TII-197 AMMONIA • • . . . • . . . . • . . . . . .... . ...... . 111-202 DANC .1

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 mono...

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 mono...

Carbon footprint assessment of recycling technologies for rare earth elements: A case study of recycling yttrium and europium from phosphor.

PubMed

Hu, Allen H; Kuo, Chien-Hung; Huang, Lance H; Su, Chao-Chin

2017-02-01

Rare earth elements are key raw materials in high-technology industries. Mining activities and manufacturing processes of such industries have caused considerable environmental impacts, such as soil erosion, vegetation destruction, and various forms of pollution. Sustaining the long-term supply of rare earth elements is difficult because of the global shortage of rare earth resources. The diminishing supply of rare earth elements has attracted considerable concern because many industrialized countries regarded such elements as important strategic resources for economic growth. This study aims to explore the carbon footprints of yttrium and europium recovery techniques from phosphor. Two extraction recovery methods, namely, acid extraction and solvent extraction, were selected for the analysis and comparison of carbon footprints. The two following functional units were used: (1) the same phosphor amounts for specific Y and Eu recovery concentrations, and (2) the same phosphor amounts for extraction. For acid extraction method, two acidic solutions (H 2 SO 4 and HCl) were used at two different temperatures (60 and 90°C). For solvent extraction method, acid leaching was performed followed by ionic liquid extraction. Carbon footprints from acid and solvent extraction methods were estimated to be 10.1 and 10.6kgCO 2 eq, respectively. Comparison of the carbon emissions of the two extraction methods shows that the solvent extraction method has significantly higher extraction efficiency, even though acid extraction method has a lower carbon footprint. These results may be used to develop strategies for life cycle management of rare earth resources to realize sustainable usage. Copyright © 2016 Elsevier Ltd. All rights reserved.

Chemical Characterization and Toxicologic Evaluation of Airborne Mixtures

DTIC Science & Technology

1981-04-01

in the chamber air (",50% relative humidity) that phosphoric acid would be the principal component of the...triphosphoric, and tetrametaphosphoric acids were present; trimeta- phosphoric and tetrapolyphosporic acids may also have been present in trace amounts. The...triphosphoric acid , diphosphoric acid , and phosphoric acid are all strong acids that, with strong bases, can be titrated in water. Titration

High Energy Halogen Chemistry.

DTIC Science & Technology

1978-01-01

underwent addition of triflic acid and of hydrochloric acid . The oxetane was polymerized ~zith phosphorous pentaflucride to ~lve a polymer stable to 2900...in aqueous dioxane . The oxetane was not affected by boron trifluoride etherate In chloroform, or by methanolic solutions of sulfuric or triflic acids ...concentrated hydrochloric acid to give 3-chloro-2-fluoro-2-nitro-l-propanol. NO • i 2 NO2OH CF I + CF SOH— 3 CF SO OCH CCH OH O OH ~ 3 3 2 2~ 2 F NO NO

Optimizing Available Phosphorus in Calcareous Soils Fertilized with Diammonium Phosphate and Phosphoric Acid Using Freundlich Adsorption Isotherm

PubMed Central

Akhtar, Muhammad

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

Bioleaching of rare earth elements from waste phosphors and cracking catalysts

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

Reed, David W.; Fujita, Yoshiko; Daubaras, Dayna L.

Four microbial cultures were evaluated for organic acid production and their potential utility for leaching of rare earth elements (REE) from retorted phosphor powder (RPP) and spent fluidized cracking catalyst (FCC). Three of the cultures (2 bacterial, 1 fungal) were isolated from environmental and industrial materials known to contain rare earth elements. The other was the well-known and industrially important bacterium Gluconobacter oxydans. Gluconic acid was the predominant identified organic acid produced by all of the cultures; citric and acetic acid were among the other acids detected. There was also maximum REE leaching by cell free culture supernatants obtained withmore » Gluconobacter and the FCC; 49% of total REE was recovered, with preferential recovery of lanthanum over cerium. The phosphor powder was more difficult to leach; only ~2 % total REE was leached from RPP with Gluconobacter. Tests with the RPP indicated that the extent of REE solubilization was similar whether whole cell cultures or cell-free supernatants were used. However, Gluconobacter cell-free culture supernatants with 10-15 mM gluconic acid outperformed abiotically prepared leaching solutions with 30 mM gluconic acid concentrations. Abiotic tests showed that increasing gluconic acid concentrations increased leaching efficiency; for example, total REE leaching from FCC increased from 24 to 36 to 45% when gluconic acid was increased from 10 to 30 to 90 mM. Our research shows that utilizing microorganisms that produce gluconic acid can result in effective leaching of REE from waste materials, and optimizing gluconic acid production will improve recovery.« less

Bioleaching of rare earth elements from waste phosphors and cracking catalysts

DOE PAGES

Reed, David W.; Fujita, Yoshiko; Daubaras, Dayna L.; ...

2016-08-22

Four microbial cultures were evaluated for organic acid production and their potential utility for leaching of rare earth elements (REE) from retorted phosphor powder (RPP) and spent fluidized cracking catalyst (FCC). Three of the cultures (2 bacterial, 1 fungal) were isolated from environmental and industrial materials known to contain rare earth elements. The other was the well-known and industrially important bacterium Gluconobacter oxydans. Gluconic acid was the predominant identified organic acid produced by all of the cultures; citric and acetic acid were among the other acids detected. There was also maximum REE leaching by cell free culture supernatants obtained withmore » Gluconobacter and the FCC; 49% of total REE was recovered, with preferential recovery of lanthanum over cerium. The phosphor powder was more difficult to leach; only ~2 % total REE was leached from RPP with Gluconobacter. Tests with the RPP indicated that the extent of REE solubilization was similar whether whole cell cultures or cell-free supernatants were used. However, Gluconobacter cell-free culture supernatants with 10-15 mM gluconic acid outperformed abiotically prepared leaching solutions with 30 mM gluconic acid concentrations. Abiotic tests showed that increasing gluconic acid concentrations increased leaching efficiency; for example, total REE leaching from FCC increased from 24 to 36 to 45% when gluconic acid was increased from 10 to 30 to 90 mM. Our research shows that utilizing microorganisms that produce gluconic acid can result in effective leaching of REE from waste materials, and optimizing gluconic acid production will improve recovery.« less

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.

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%. © International & American Associations for Dental Research.

Comparison of enamel bond fatigue durability between universal adhesives and two-step self-etch adhesives: Effect of phosphoric acid pre-etching.

PubMed

Suda, Shunichi; Tsujimoto, Akimasa; Barkmeier, Wayne W; Nojiri, Kie; Nagura, Yuko; Takamizawa, Toshiki; Latta, Mark A; Miyazaki, Masashi

2018-03-30

The effect of phosphoric acid pre-etching on enamel bond fatigue durability of universal adhesives and two-step self-etch adhesives was investigated. Four universal adhesives and three two-step self-etch adhesives were used. The initial shear bond strengths and shear fatigue strengths to enamel with and without phosphoric acid pre-etching using the adhesives were determined. SEM observations were also conducted. Phosphoric acid pre-etching of enamel was found to increase the bond fatigue durability of universal adhesives, but its effect on two-step self-etch adhesives was material-dependent. In addition, some universal adhesives with phosphoric acid pre-etching showed similar bond fatigue durability to the two-step self-etch adhesives, although the bond fatigue durability of universal adhesives in self-etch mode was lower than that of the two-step self-etch adhesives. Phosphoric acid pre-etching enhances enamel bond fatigue durability of universal adhesives, but the effect of phosphoric acid pre-etching on the bond fatigue durability of two-step self-etch adhesives was material-dependent.

PROCESS OF REMOVING PLUTONIUM VALUES FROM SOLUTION WITH GROUP IVB METAL PHOSPHO-SILICATE COMPOSITIONS

DOEpatents

Russell, E.R.; Adamson, A.W.; Schubert, J.; Boyd, G.E.

1957-10-29

A process for separating plutonium values from aqueous solutions which contain the plutonium in minute concentrations is described. These values can be removed from an aqueous solution by taking an aqueous solution containing a salt of zirconium, titanium, hafnium or thorium, adding an aqueous solution of silicate and phosphoric acid anions to the metal salt solution, and separating, washing and drying the precipitate which forms when the two solutions are mixed. The aqueous plutonium containing solution is then acidified and passed over the above described precipi-tate causing the plutonium values to be adsorbed by the precipitate.

Comparison of Four Strong Acids on the Precipitation Potential of Gypsum in Brines During Distillation of Pretreated, Augmented Urine

NASA Technical Reports Server (NTRS)

Muirhead, Dean; Carrier, Christopher

2012-01-01

In this study, three different mineral acids were substituted for sulfuric acid (H2SO4) in the urine stabilizer solution to eliminate the excess of sulfate ions in pretreated urine and assess the impact on maximum water recovery to avoid precipitation of minerals during distillation. The study evaluated replacing 98% sulfuric acid with 85% phosphoric acid (H3PO4), 37% hydrochloric acid (HCl), or 70% nitric acid (HNO3). The effect of lowering the oxidizer concentration in the pretreatment formulation also was studied. This paper summarizes the test results, defines candidate formulations for further study, and specifies the injection masses required to stabilize urine and minimize the risk of mineral precipitation during distillation. In the first test with a brine ersatz acidified with different acids, the solubility of calcium in gypsum saturated solutions was measured. The solubility of gypsum was doubled in the brines acidified with the alternative acids compared to sulfuric acid. In a second series of tests, the alternative acid pretreatment concentrations were effective at preventing precipitation of gypsum and other minerals up to 85% water recovery from 95th-percentile pretreated, augmented urine. Based on test results, phosphoric acid is recommended as the safest alternative to sulfuric acid. It also is recommended that the injected mass concentration of chromium trioxide solution be reduced by 75% to minimize liquid resupply mass by about 50%, reduce toxicity of brines, and reduce the concentration of organic acids in distillate. The new stabilizer solution formulations and required doses to stabilize urine and prevent precipitation of minerals up to 85% water recovery are given. The formulations in this study were tested on a limited number of artificially augmented urine batches collected from employees at the Johnson Space Center (JSC). This study successfully demonstrated that the desired physical and chemical stability of pretreated urine and brines can be achieved using alternate pretreatment formulations under laboratory conditions. Additional testing and hazard assessments will be required to determine the feasibility of utilizing the proposed urine pretreatment formulations on ISS.

Installation Restoration Program. Phase I. Records Search, Vance Air Force Base, Oklahoma.

DTIC Science & Technology

1984-07-01

cadmium , and descaling solutions. The general trend in waste disposal over the years since VAFB first began operation has been from 3 largely unsegregated...generated at the jet engine shop and metal plating shops and consists of phosphoric acid, chromic acid, potassium permanganate, cadmium , and descaling...benzene, MIBK, carbon tetrachloride, MEK, methylene chloride, and acetone. The metal analytes should include cadmium , chromium, copper, iron, lead

Purification of dirucotide, a synthetic 17-aminoacid peptide, by ion exchange centrifugal partition chromatography.

PubMed

Boudesocque, Leslie; Forni, Luciano; Martinez, Agathe; Nuzillard, Jean-Marc; Giraud, Matthieu; Renault, Jean-Hugues

2017-09-01

Dirucotide is a synthetic drug candidate for the treatment of multiple sclerosis. This 17-aminoacid peptide was successfully purified by ion exchange centrifugal partition chromatography. The optimized conditions involved the biphasic methyl tert-butyl ether/acetonitrile/n-butanol/water (2:1:2:5, v/v) solvent system in the descending mode, the di(2-ethylhexyl)phosphoric acid cation-exchanger with an exchanger (di(2-ethylhexyl)phosphoric acid)/dirucotide mole ratio of 100 and Ca 2+ ions in aqueous solution as displacer. Critical impurities were efficiently eliminated and dirucotide was recovered in high yield and purity (69% and 98%, respectively) and with a productivity of 2.29g per liter of stationary phase per hour. Copyright © 2017 Elsevier B.V. All rights reserved.

Case Study: Fuel Cells Provide Combined Heat and Power at Verizon's Garden City Central Office

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

None

2010-12-01

This case study describes how Verizon's Central Office in Garden City, NY, installed a 1.4-MW phosphoric acid fuel cell system as an alternative solution to bolster electric reliability, optimize the company's energy use, and reduce costs in an environmentally responsible manner.

Tactical Video Display.

DTIC Science & Technology

1981-02-01

steady state. A substrate temperatue during the deposition of the ZnS phosphor of about 220-240 0 C seems very compatible to maximize all the physio...create a severe problem for the etching characteristics of the back elec- trode (Al). Zn and Al can both be etched by alkaline and acidic solution. Few

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

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

Onoda, Hiroaki, E-mail: onoda@kpu.ac.jp; Matsukura, Aki

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 obtainedmore » 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.« less

Phosphoric acid addition effect on the microstructure and magnetic properties of iron-based soft magnetic composites

NASA Astrophysics Data System (ADS)

Hsiang, Hsing-I.; Fan, Liang-Fang; Hung, Jia-Jing

2018-02-01

The phosphoric acid addition effect on phosphate insulation coating microstructure was investigated in this study. The relationships between the phosphate insulation coating microstructure and temperature resistance, corrosion resistance and magnetic properties of iron-based soft magnetic composites (SMCs) were studied by using SEM, TEM/EDS and FTIR. It was observed that an iron phosphate/carbonyl iron core/shell structure is formed with carbonyl iron powder after phosphatizing treatment. The iron phosphate phase was identified as amorphous and its thickness increased from 30 nm to 60 nm as the phosphoric acid concentration was increased from 1 wt% to 2 wt%. When the phosphoric acid concentration was further increased to 5 wt%, the excess iron phosphate precipitates between the soft magnetic composite particles. The temperature and corrosion resistance and resistivity of the iron-based SMCs can be effectively improved using carbonyl iron powders after phosphatizing. The initial permeability of the iron-based SMCs decreased with increasing phosphoric acid concentration due to thicker insulation layer formation. However, the imaginary permeability below the domain wall displacement resonance frequency decreased with increasing phosphoric acid concentration. The DC-bias superposition characteristic can also be improved by increasing the phosphoric acid concentration. Iron-based SMCs with superior temperature and corrosion resistance, initial permeability, magnetic loss and DC-bias superposition characteristics can be obtained by controlling the phosphoric acid concentration during phosphatizing to adjust the iron phosphate precipitate thickness on the iron powder surface.

Proton Conductivity in Phosphoric Acid: The Role of Quantum Effects

DOE PAGES

Heres, M.; Wang, Y.; Griffin, P. J.; ...

2016-10-07

Phosphoric acid has one of the highest intrinsic proton conductivities of any known liquids, and the mechanism of this exceptional conductivity remains a puzzle. In our detailed experimental studies we 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. Our 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.

Structural and morphological changes in supramolecular-structured polymer electrolyte membrane fuel cell on addition of phosphoric acid

NASA Astrophysics Data System (ADS)

Hendrana, S.; Pryliana, R. F.; Natanael, C. L.; Rahayu, I.

2018-03-01

Phosphoric acid is one agents used in membrane fuel cell to modify ionic conductivity. Therefore, its distribution in membrane is a key parameter to gain expected conductivity. Efforts have been made to distribute phosphoric acid in a supramolecular-structured membrane prepared with a matrix. To achieve even distribution across bulk of the membrane, the inclusion of the polyacid is carried out under pressurized chamber. Image of scanning electron microscopy (SEM) shows better phosphoric acid distribution for one prepared in pressurized state. It also leads in better performing in ionic conductivity. Moreover, data from differential scanning calorimetry (DSC) indicate that the addition of phosphoric acid is prominent in the change of membrane structure, while morphological changes are captured in SEM images.

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.

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

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

Takahashi, Kouta, E-mail: ktakahas@alice.xtal.nagoya-u.ac.jp, E-mail: kurosawa@alice.xtal.nagoya-u.ac.jp; Sakashita, Mitsuo; Takeuchi, Wakana

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 × 10{sup 19} cm{sup −3} was realized by 1000-times laser shots at a laser energy of 1.0 J/cm{sup 2}, 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 biasmore » 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.« less

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

Code of Federal Regulations, 2011 CFR

2011-07-01

... AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD... exemption from the requirement of a tolerance is established for residues of phosphorous acid and its... and in or on potatoes when applied as a post-harvest treatment at 35,600 ppm or less phosphorous acid...

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

Code of Federal Regulations, 2010 CFR

2010-07-01

... AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD... exemption from the requirement of a tolerance is established for residues of phosphorous acid and its... and in or on potatoes when applied as a post-harvest treatment at 35,600 ppm or less phosphorous acid...

Electrocatalysis of fuel cell reactions: Investigation of alternate electrolytes

NASA Technical Reports Server (NTRS)

Chin, D. T.; Hsueh, K. L.; Chang, H. H.

1983-01-01

Oxygen reduction and transport properties of the electrolyte in the phosphoric acid fuel cell are studied. A theoretical expression for the rotating ring-disk electrode technique; the intermediate reaction rate constants for oxygen reduction on platinum in phosphoric acid electrolyte; oxygen reduction mechanism in trifluoromethanesulfonic acid (TFMSA), considered as an alternate electrolyte for the acid fuel cells; and transport properties of the phosphoric acid electrolyte at high concentrations and temperatures are covered.

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

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

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 typemore » of study, but care must be taken with the choice of standard and method of analysis.« less

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.

Influence of enamel conditioning on the shear bond strength of different adhesives.

PubMed

Brauchli, Lorenz; Muscillo, Teodoro; Steineck, Markus; Wichelhaus, Andrea

2010-11-01

Phosphoric acid etching is the gold standard for enamel conditioning. However, it is possible that air abrasion or a combination of air abrasion and etching might result in enhanced adhesion. The aim of this study was to investigate the effect of different enamel conditioning methods on the bond strength of six adhesives. Three different enamel conditioning procedures (phosphoric acid etching, air abrasion, air abrasion + phosphoric acid etching) were evaluated for their influence on the shear bond strength of six different adhesives (Transbond™ XT, Cool-Bond™, Fuji Ortho LC, Ultra Band-Lok, Tetric(®) Flow, Light-Bond™). Each group consisted of 15 specimens. Shear forces were measured with a universal testing machine. The scores of the Adhesive Remnant Index (ARI) were also analyzed. There were no significant differences between phosphoric acid etching and air abrasion + phosphoric acid etching. Air abrasion as a single conditioning technique led to significantly lower shear forces. The ARI scores did not correlate with the shear strengths measured. There were greater variations in shear forces for the different adhesives than for the conditioning techniques. The highest shear forces were found for the conventional composites Transbond™ XT and Cool- Bond™ in combination with conventional etching. Air abrasion alone and in combination with phosphoric acid etching showed no advantages compared with phosphoric acid etching alone and, therefore, cannot be recommended.

Electrolytes for Hydrocarbon Air Fuel Cells.

DTIC Science & Technology

1981-01-01

finding an electrolyte with sufficient electrochemical activity and stability to replace phosphoric acid in direct oxidation fuel cells. Commercially...and stability to replace phosphoric acid in direct oxidation fuel cells. Commercially available materials received prime consideration. However, ECO’s...was to obtain an electrolyte with sufficient electrochemical activity and stability to replace phosphoric acid in direct oxidation fuel cells. This

Phosphoric acid as an electrolyte additive for lead/acid batteries in electric-vehicle applications

NASA Astrophysics Data System (ADS)

Meissner, E.

The influence of the addition of phosphoric acid to the electrolyte on the performance of gelled lead/acid electric-vehiicle batteries is investigated. This additive reduces the reversible capacity decay of the positive electrode significantly which is observed upon extended cycling when recharge of the battery is performed at low initial rate. This is important when low-rate on-board chargers are used. Pulsed discharge, typical for electric-vehicle application, induces reversible capacity decay more than constant-current discharge at a same depth-of-discharge, as well with as without the addition of phosphoric acid. By contrast, hindrance in presence of H 3PO 4 for both the recharge and the discharge reaction helps to homogenize the state of many individual cells during cycling in long battery strings. Reversible capacity loss, which occurs after extended cycling and when pulsed discharge is applied, can be recovered by a single discharge at very low rate with batteries with and without the addition of phosphoric acid. The discharge-rate dependency of the capacity is significantly reduced when phosphoric acid is added. The pulse discharge behaviour may be better, even if the nominal capacity is reduced. The experimental findings of the influence of phosphoric acid addition is discussed in terms of the aggregate-of-spheres model of reversible capacity decay.

The Effect of Phosphoric Acid Pre-etching Times on Bonding Performance and Surface Free Energy with Single-step Self-etch Adhesives.

PubMed

Tsujimoto, A; Barkmeier, W W; Takamizawa, T; Latta, M A; Miyazaki, M

2016-01-01

The purpose of this study was to evaluate the effect of phosphoric acid pre-etching times on shear bond strength (SBS) and surface free energy (SFE) with single-step self-etch adhesives. The three single-step self-etch adhesives used were: 1) Scotchbond Universal Adhesive (3M ESPE), 2) Clearfil tri-S Bond (Kuraray Noritake Dental), and 3) G-Bond Plus (GC). Two no pre-etching groups, 1) untreated enamel and 2) enamel surfaces after ultrasonic cleaning with distilled water for 30 seconds to remove the smear layer, were prepared. There were four pre-etching groups: 1) enamel surfaces were pre-etched with phosphoric acid (Etchant, 3M ESPE) for 3 seconds, 2) enamel surfaces were pre-etched for 5 seconds, 3) enamel surfaces were pre-etched for 10 seconds, and 4) enamel surfaces were pre-etched for 15 seconds. Resin composite was bonded to the treated enamel surface to determine SBS. The SFEs of treated enamel surfaces were determined by measuring the contact angles of three test liquids. Scanning electron microscopy was used to examine the enamel surfaces and enamel-adhesive interface. The specimens with phosphoric acid pre-etching showed significantly higher SBS and SFEs than the specimens without phosphoric acid pre-etching regardless of the adhesive system used. SBS and SFEs did not increase for phosphoric acid pre-etching times over 3 seconds. There were no significant differences in SBS and SFEs between the specimens with and without a smear layer. The data suggest that phosphoric acid pre-etching of ground enamel improves the bonding performance of single-step self-etch adhesives, but these bonding properties do not increase for phosphoric acid pre-etching times over 3 seconds.

Removing oxygen from a solvent extractant in an uranium recovery process

DOEpatents

Hurst, Fred J.; Brown, Gilbert M.; Posey, Franz A.

1984-01-01

An improvement in effecting uranium recovery from phosphoric acid solutions is provided by sparging dissolved oxygen contained in solutions and solvents used in a reductive stripping stage with an effective volume of a nonoxidizing gas before the introduction of the solutions and solvents into the stage. Effective volumes of nonoxidizing gases, selected from the group consisting of argon, carbon dioxide, carbon monoxide, helium, hydrogen, nitrogen, sulfur dioxide, and mixtures thereof, displace oxygen from the solutions and solvents thereby reduce deleterious effects of oxygen such as excessive consumption of elemental or ferrous and accumulation of complex iron phosphates or cruds.

Rapid determination of thiamine, riboflavin, niacinamide, pantothenic acid, pyridoxine, folic acid and ascorbic acid in Vitamins with Minerals Tablets by high-performance liquid chromatography with diode array detector.

PubMed

Jin, Pengfei; Xia, Lufeng; Li, Zheng; Che, Ning; Zou, Ding; Hu, Xin

2012-11-01

A simple, isocratic, and stability-indicating high-performance liquid chromatography (HPLC) method has been developed for the rapid determination of thiamine (VB(1)), niacinamide (VB(3)), pyridoxine (VB(6)), ascorbic acid (VC), pantothenic acid (VB(5)), riboflavin (VB(2)) and folic acid (VB(9)) in Vitamins with Minerals Tablets (VMT). An Alltima C(18) column (250 mm × 4.6 mm i.d., 5 μm) was used for the separation at ambient temperature, with 50mM ammonium dihydrogen phosphate (adjusting with phosphoric acid to pH 3.0) and acetonitrile as the mobile phase at the flow rate of 0.5 ml min(-1). VB(1), VB(3), VB(6), VC and VB(5) were extracted with a solution containing 0.05% phosphoric acid (v/v) and 0.3% sodium thiosulfate (w/v), and were then simultaneously analyzed by using the mobile phase of phosphate buffer-acetonitrile (95:5, v/v), while VB(2) and VB(9) were extracted with a solution containing 0.5% ammonium hydroxide solution (v/v), and were then simultaneously analyzed by using the mobile phase of phosphate buffer-acetonitrile (85:15, v/v). The detection wavelengths were 275 nm for VB(1), VB(3), VB(6), VC, 210 nm for VB(5), and 282 nm for VB(2) and VB(9). The method showed good system suitability, sensitivity, linearity, specificity, precision, stability and accuracy. All the seven water-soluble vitamins were well separated from other ingredients and degradation products. Method comparison indicated good concordance between the developed method and the USP method. The developed method was reliable and convenient for the rapid determination of VB(1), VB(3), VB(6), VC, VB(5), VB(2) and VB(9) in VMT. Copyright © 2012 Elsevier B.V. All rights reserved.

World wide IFC phosphoric acid fuel cell implementation

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

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.

Effects of different surface treatments and accelerated artificial aging on the bond strength of composite resin repairs.

PubMed

Melo, Marco Aurélio Veiga de; Moysés, Marcos Ribeiro; Santos, Saulo Galvão dos; Alcântara, Carlos Eduardo Pinto; Ribeiro, José Carlos Rabelo

2011-01-01

The purpose of the present study was to assess the bond strength of composite resin repairs subjected to different surface treatments and accelerated artificial aging. 192 cylindrical samples (CSs) were prepared and divided into 24 groups (n = 8). Half of the CSs were stored in water for 24 h, and the other half were subjected to C-UV accelerated aging for non-metallic specimens. The treatments were phosphoric acid + silane + adhesive (PSA); phosphoric acid + adhesive (PA); diamond bur + phosphoric acid + silane + adhesive (DPSA); diamond bur + phosphoric acid + adhesive (DPA); air abrasion + phosphoric acid + silane + adhesive (APSA); and air abrasion + phosphoric acid + adhesive (APA). The repair was performed and the specimens were again aged as described above. A control group (n = 8) was established and did not receive any type of aging or surface treatment. The specimens were loaded to failure in shear mode with a crosshead speed of 0.5 mm/min until fracture. Data were analyzed by one-way ANOVA/Tukey's test (p < 0.05). No statistically significant differences were found among DPSA, DPA, APSA, APA, and the control group. The aged PSA and PA achieved low bonding values and were statistically different from the control group, whereas the non-aged PSA and PA presented no statistically significant difference from the control group. Repairs with the proposed surface treatments were viable on both recent and aged restorations; however, phosphoric acid + adhesive alone were effective only on recent restorations.

Synthesis of nano-crystalline hydroxyapatite and ammonium sulfate from phosphogypsum waste

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

Mousa, Sahar, E-mail: dollyriri@yahoo.com; King Abdulaziz University, Science and Art College, Chemistry Department, Rabigh Campus, P.O. Box:344, Postal code: 21911 Rabigh; Hanna, Adly

2013-02-15

Graphical abstract: TEM micrograph of dried HAP at 800 °C. -- Abstract: Phosphogypsum (PG) waste which is derived from phosphoric acid manufacture by using wet method was converted into hydroxyapatite (HAP) and ammonium sulfate. Very simple method was applied by reacting PG with phosphoric acid in alkaline medium with adjusting pH using ammonia solution. The obtained nano-HAP was dried at 80 °C and calcined at 600 °C and 900 °C for 2 h. Both of HAP and ammonium sulfate were characterized by X-ray diffraction (XRD) and infrared spectroscopy (IR) to study the structural evolution. The thermal behavior of nano-HAP wasmore » studied; the particle size and morphology were estimated by using transmission electron microscopy (TEM) and scanning electron microscopy (SEM). All the results showed that HAP nano-crystalline and ammonium sulfate can successfully be produced from phosphogypsum waste.« less

Shear bond strength of self-etch adhesives to enamel with additional phosphoric acid etching.

PubMed

Lührs, Anne-Katrin; Guhr, Silke; Schilke, Reinhard; Borchers, Lothar; Geurtsen, Werner; Günay, Hüsamettin

2008-01-01

This study evaluated the shear bond strength of self-etch adhesives to enamel and the effect of additional phosphoric acid etching. Seventy sound human molars were randomly divided into three test groups and one control group. The enamel surfaces of the control group (n=10) were treated with Syntac Classic (SC). Each test group was subdivided into two groups (each n=10). In half of each test group, ground enamel surfaces were coated with the self-etch adhesives AdheSe (ADH), Xeno III (XE) or Futurabond NR (FNR). In the remaining half of each test group, an additional phosphoric acid etching of the enamel surface was performed prior to applying the adhesives. The shear bond strength was measured with a universal testing machine at a crosshead speed of 1 mm/minute after storing the samples in distilled water at 37 degrees C for 24 hours. Fracture modes were determined by SEM examination. For statistical analysis, one-way ANOVA and the two-sided Dunnett Test were used (p>0.05). Additional phosphoric etching significantly increased the shear bond strength of all the examined self-etch adhesives (p<0.001). The highest shear bond strength was found for FNR after phosphoric acid etching. Without phosphoric acid etching, only FNR showed no significant differences compared to the control (SC). SEM evaluations showed mostly adhesive fractures. For all the self-etch adhesives, a slight increase in mixed fractures occurred after conditioning with phosphoric acid. An additional phosphoric acid etching of enamel should be considered when using self-etch adhesives. More clinical studies are needed to evaluate the long-term success of the examined adhesives.

Dibutyl Phosphoric Acid Solubility in High-Acid, Uranium-Bearing Solutions at SRS

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

Pierce, R.A.

1998-10-02

The Savannah River Site has enriched uranium (EU) solution which has been stored for almost 10 years since being purified in the second uranium cycle of the H area solvent extraction process. The concentrations in solution are approximately 6 g/L U and about 0.1 M nitric acid. Residual tributylphosphate in the solutions has slowly hydrolyzed to form dibutyl phosphoric acid (HDBP) at concentrations averaging 50 mg/L. Uranium is known to form compounds with the dibutylphosphate ion (DBP) which have limited solubility. The potential to form uranium-DBP solids raises a nuclear criticality safety issue. Prior SRTC tests (WSRC-TR-98-00188) showed that U-DBPmore » solids precipitate at concentrations potentially attainable during the storage of enriched uranium solutions. Furthermore, evaporation of the existing EUS solution without additional acidification could result in the precipitation of U-DBP solids if the DBP concentration in the resulting solution exceeds 110 mg/L at ambient temperature. The same potential exists for evaporation of unwashed 1CU solutions. As a follow-up to the earlier studies, SRTC studied the solubility limits for solutions containing acid concentrations above 0.5M HNO3. The data obtained in these tests reveals a shift to higher levels of DBP solubility above 0.5M HNO3 for both 6 g/L and 12 g/L uranium solutions. Analysis of U-DBP solids from the tests identified a mixture of different molecular structures for the solids created. The analysis distinguished UO2(DBP)2 as the dominant compound present at low acid concentrations. As the acid concentration increases, the crystalline UO2(DBP)2 shows molecular substitutions and an increase in amorphous content. Further analysis by methods not available at SRS will be needed to better identify the specific compounds present. This data indicates that acidification prior to evaporation can be used to increase the margin of safety for the storage of the EUS solutions. Subsequent experimentation evaluated options for absorbing HDBP from solution using either activated carbon or anion exchange resin. The activated carbon outperformed the anion exchange resin. Activated carbon absorbs DBP rapidly and has demonstrated the capability of absorbing 15 mg of DBP per gram of activated carbon. Analytical results also show that activated carbon absorbs uranium up to 17 mg per gram of carbon. It is speculated that the uranium absorbed is part of a soluble U-DBP complex that has been absorbed. Additional testing must still be performed to 1) establish absorption limits for uranium for anion exchange resin, 2) evaluate desorption characteristics of uranium and DBP, and 3) study the possibility of re-using the absorbent.« less

NUCLEAR REACTOR FUEL SYSTEMS

DOEpatents

Thamer, B.J.; Bidwell, R.M.; Hammond, R.P.

1959-09-15

Homogeneous reactor fuel solutions are reported which provide automatic recombination of radiolytic gases and exhibit large thermal expansion characteristics, thereby providing stability at high temperatures and enabling reactor operation without the necessity of apparatus to recombine gases formed by the radiolytic dissociation of water in the fuel and without the necessity of liquid fuel handling outside the reactor vessel except for recovery processes. The fuels consist of phosphoric acid and water solutions of enriched uranium, wherein the uranium is in either the hexavalent or tetravalent state.

Drinking Water Criteria for the Groundwater Pollutant Diisopropyl Methylphosphonate (DIMP).

DTIC Science & Technology

1987-07-01

methylphosphonate, phosphoric acid , isopropyl alcohol, and S--propylene. DIMP forms a number of metal complexes in the absence of moisture. 1 7-19 For a...triisopropyl phosphite .7𔄂 Other methods are mentioned in the patent literature.9-11 The solubility limit of DIMP in water has not been determined. In studies...of DIMP hydrolysis in acidic and basic solutions, 12 0.12 N or higher DIMP was used at temperatures above 800 C, indicating solubilities of above 11 g

Electrocatalysis of fuel cell reactions: Investigation of alternate electrolytes

NASA Technical Reports Server (NTRS)

Chin, D. T.; Hsueh, K. L.; Chang, H. H.

1984-01-01

Oxygen reduction and transport properties of the electrolyte in the phosphoric acid fuel cell are studied. The areas covered were: (1) development of a theoretical expression for the rotating ring disk electrode technique; (2) determination of the intermediate reaction rate constants for oxygen reduction on platinum in phosphoric acid electrolyte; (3) determination of oxygen reduction mechanism in trifluoreomethanesulfonic acid (TFMSA) which was considered as an alternate electrolyte for the acid fuel cells; and (4) the measurement of transport properties of the phosphoric acid electrolyte at high concentrations and temperatures.

Contact Whiskers for Millimeter Wave Diodes

NASA Technical Reports Server (NTRS)

Kerr, A. R.; Grange, J. A.; Lichtenberger, J. A.

1978-01-01

Several techniques are investigated for making short conical tips on wires (whiskers) used for contacting millimeter-wave Schottky diodes. One procedure, using a phosphoric and chromic acid etching solution (PCE), is found to give good results on 12 microns phosphor-bronze wires. Full cone angles of 60 degrees-80 degrees are consistently obtained, compared with the 15 degrees-20 degrees angles obtained with the widely used sodium hydroxide etch. Methods are also described for cleaning, increasing the tip diameter (i.e. blunting), gold plating, and testing the contact resistance of the whiskers. The effects of the whisker tip shape on the electrical resistance, inductance, and capacitance of the whiskers are studied, and examples given for typical sets of parameters.

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... 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 P-90-1985...

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

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 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 P-90-1985...

Method for oxygen reduction in a uranium-recovery process. [US DOE patent application

DOEpatents

Hurst, F.J.; Brown, G.M.; Posey, F.A.

1981-11-04

An improvement in effecting uranium recovery from phosphoric acid solutions is provided by sparging dissolved oxygen contained in solutions and solvents used in a reductive stripping stage with an effective volume of a nonoxidizing gas before the introduction of the solutions and solvents into the stage. Effective volumes of nonoxidizing gases, selected from the group consisting of argon, carbon dioxide, carbon monoxide, helium, hydrogen, nitrogen, sulfur dioxide, and mixtures thereof, displace oxygen from the solutions and solvents thereby reduce deleterious effects of oxygen such as excessive consumption of elemental or ferrous iron and accumulation of complex iron phosphates or cruds.

TREATMENT OF URANIUM SURFACES

DOEpatents

Slunder, C.J.

1959-02-01

An improved process is presented for prcparation of uranium surfaces prior to electroplating. The surfacc of the uranium to be electroplated is anodized in a bath comprising a solution of approximately 20 to 602 by weight of phosphoric acid which contains about 20 cc per liter of concentrated hydrochloric acid. Anodization is carried out for approximately 20 minutes at a current density of about 0.5 amperes per square inch at a temperature of about 35 to 45 C. The oxidic film produced by anodization is removed by dipping in strong nitric acid, followed by rinsing with water just prior to electroplating.

Enrichment of Sc2O3 and TiO2 from bauxite ore residues.

PubMed

Deng, Bona; Li, Guanghui; Luo, Jun; Ye, Qing; Liu, Mingxia; Peng, Zhiwei; Jiang, Tao

2017-06-05

As a major byproduct generated in the alumina industry, bauxite ore residue is an important reserve of scandium and titanium. In this study, the feasibility and mechanism of enriching Sc 2 O 3 and TiO 2 from a non-magnetic material, which was obtained from carbothermal reductive roasting and magnetic separation of bauxite ore residue, were investigated based on a two-step (acidic and alkali) leaching process. It was revealed that approximately 78% SiO 2 and 30-40% of CaO, FeO and Al 2 O 3 were removed from a non-magnetic material with 0.0134wt.% Sc 2 O 3 and 7.64wt.% TiO 2 by phosphoric acidic leaching, while about 95% Al 2 O 3 and P 2 O 5 were further leached by subsequent sodium hydroxide leaching of the upper-stream leach residue. A Sc 2 O 3 -, TiO 2 - rich material containing 0.044wt.% Sc 2 O 3 and 25.5wt.% TiO 2 was obtained, the recovery and the enrichment factor of Sc 2 O 3 and TiO 2 were about 85% and 5, respectively. The enrichment of Sc 2 O 3 was attributed to higher pH (>3.3) of phosphoric acid solution than its dissolution pH 0 , and the enrichment of TiO 2 was mainly associated with the insoluble perovskite (CaTiO 3 ) in the acidic solution at ambient temperature. As Sc 2 O 3 and TiO 2 cannot be dissolved in the alkali solution, they were further enriched in the leach residue. Copyright © 2017 Elsevier B.V. All rights reserved.

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

Code of Federal Regulations, 2014 CFR

2014-04-01

... section, partial phosphoric acid esters of polyester 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... characterizing the type of food and under the conditions of time and temperature characterizing the conditions of...

On the nanosecond proton dynamics in phosphoric acid–benzimidazole and phosphoric acid–water mixtures

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

Melchior, Jan-Patrick; Frick, Bernhard

Combining 1H-NMR, 17O-NMR, and high-resolution backscattering QENS hydrodynamic and structural proton transport in phosphoric acid is separated. The rate limiting steps for structural proton diffusion in mixtures of acid with Brønsted bases are found to occur below the nanosecond timescale.

On the nanosecond proton dynamics in phosphoric acid–benzimidazole and phosphoric acid–water mixtures

DOE PAGES

Melchior, Jan-Patrick; Frick, Bernhard

2017-09-22

Combining 1H-NMR, 17O-NMR, and high-resolution backscattering QENS hydrodynamic and structural proton transport in phosphoric acid is separated. The rate limiting steps for structural proton diffusion in mixtures of acid with Brønsted bases are found to occur below the nanosecond timescale.

Phosphoric acid as an asphalt modifier guidelines for use : acid type.

DOT National Transportation Integrated Search

2008-01-01

Any grade of phosphoric acid can be used as an asphalt modifier. The stiffening effect is asphalt dependent. All grades of acid will yield similar results. However, the more diluted grades contain water, which may result in foaming problems as the wa...

40 CFR 60.201 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-07-01

...-Process Phosphoric Acid Plants § 60.201 Definitions. As used in this subpart, all terms not defined herein... acid plant means any facility manufacturing phosphoric acid by reacting phosphate rock and acid. (b) Total fluorides means elemental fluorine and all fluoride compounds as measured by reference methods...

40 CFR 60.201 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-07-01

...-Process Phosphoric Acid Plants § 60.201 Definitions. As used in this subpart, all terms not defined herein... acid plant means any facility manufacturing phosphoric acid by reacting phosphate rock and acid. (b) Total fluorides means elemental fluorine and all fluoride compounds as measured by reference methods...

40 CFR 60.201 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-07-01

...-Process Phosphoric Acid Plants § 60.201 Definitions. As used in this subpart, all terms not defined herein... acid plant means any facility manufacturing phosphoric acid by reacting phosphate rock and acid. (b) Total fluorides means elemental fluorine and all fluoride compounds as measured by reference methods...

40 CFR 60.201 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-07-01

...-Process Phosphoric Acid Plants § 60.201 Definitions. As used in this subpart, all terms not defined herein... acid plant means any facility manufacturing phosphoric acid by reacting phosphate rock and acid. (b) Total fluorides means elemental fluorine and all fluoride compounds as measured by reference methods...

40 CFR 60.201 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

...-Process Phosphoric Acid Plants § 60.201 Definitions. As used in this subpart, all terms not defined herein... acid plant means any facility manufacturing phosphoric acid by reacting phosphate rock and acid. (b) Total fluorides means elemental fluorine and all fluoride compounds as measured by reference methods...

Photoluminescence in Sm3+ doped Ba2P2O7 phosphor prepared by solution combustion method

NASA Astrophysics Data System (ADS)

Ghawade, Sonal P.; Deshmukh, Kavita A.; Dhoble, S. J.; Deshmukh, Abhay D.

2018-05-01

In this paper, Sm3+ doped Ba2P2O7 phosphors were synthesized via a Solution combustion method. The crystal structure of the phosphor was characterized by XRD. Orange-red emission was observed from these phosphors under near-ultraviolet (UV) excitation at 404 nm. The luminescence properties of the obtained phosphors were characterized by different techniques. The Ba2P2O7:Sm3+ phosphor can be efficiently excited by near-UV and blue light, and their emission spectrum consists of three emission peaks, at 564, 602, and 646 nm, respectively. Based on the results, the as prepared Ba2P2O7:Sm3+ phosphors are promising orange-red-emitting phosphors exhibit great potential may be applicable as a spectral convertor in c-Si solar cell to enhance the efficiency of solar cell in future.

Removal of free fatty acid in Azadirachta indica (Neem) seed oil using phosphoric acid modified mordenite for biodiesel production.

PubMed

SathyaSelvabala, Vasanthakumar; Varathachary, Thiruvengadaravi Kadathur; Selvaraj, Dinesh Kirupha; Ponnusamy, Vijayalakshmi; Subramanian, Sivanesan

2010-08-01

In this study free fatty acids present in Azadirachta indica (Neem) oil were esterified with our synthesized phosphoric acid modified catalyst. During the esterification, the acid value was reduced from 24.4 to 1.8 mg KOH/g oil. Synthesized catalyst was characterized by NH(3) TPD, XRD, SEM, FTIR and TGA analysis. During phosphoric acid modification hydrophobic character and weak acid sites of the mordenite were increased, which lead to better esterification when compared to H-mordenite. A kinetic study demonstrates that the esterification reaction followed pseudo-first order kinetics. Thermodynamic studies were also done based on the Arrhenius model. (c) 2010 Elsevier Ltd. All rights reserved.

Potential uranium supply from phosphoric acid: A U.S. analysis comparing solvent extraction and Ion exchange recovery

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

Kim, Haeyeon; G. Eggert, Roderick; W. Carlsen, Brett

Phosphate rock contains significant amounts of uranium, although in low concentrations. Recovery of uranium as a by-product from phosphoric acid, an intermediate product produced during the recovery of phosphorus from phosphate rock, is not unprecedented. Phosphoric acid plants ceased to produce uranium as a by-product in the early 1990s with the fall of uranium prices. In the last decade, this topic has regained attention due to higher uranium prices and expected increase in demand for uranium. Our study revisits the topic and estimates how much uranium might be recoverable from current phosphoric acid production in the United States and whatmore » the associated costs might be considering two different recovery processes: solvent extraction and ion exchange. Based on U.S. phosphoric acid production in 2014, 5.5 million pounds of U 3O 8 could have been recovered, more than domestic U.S. mine production of uranium in the same year. Annualized costs for a hypothetical uranium recovery plant are US$48-66 per pound U 3O 8 for solvent extraction, the process used historically in the United States to recover uranium from phosphoric acid. For ion exchange, not yet proven at a commercial scale for uranium recovery, the estimated costs are US$33-54 per pound U 3O 8. Our results suggest that it is technically possible for the United States to recover significant quantities of uranium from current phosphoric acid production. And for this type of uranium production to be economically attractive on a large scale, either recovery costs must fall or uranium prices rise.« less

Potential uranium supply from phosphoric acid: A U.S. analysis comparing solvent extraction and Ion exchange recovery

DOE PAGES

Kim, Haeyeon; G. Eggert, Roderick; W. Carlsen, Brett; ...

2016-06-16

Phosphate rock contains significant amounts of uranium, although in low concentrations. Recovery of uranium as a by-product from phosphoric acid, an intermediate product produced during the recovery of phosphorus from phosphate rock, is not unprecedented. Phosphoric acid plants ceased to produce uranium as a by-product in the early 1990s with the fall of uranium prices. In the last decade, this topic has regained attention due to higher uranium prices and expected increase in demand for uranium. Our study revisits the topic and estimates how much uranium might be recoverable from current phosphoric acid production in the United States and whatmore » the associated costs might be considering two different recovery processes: solvent extraction and ion exchange. Based on U.S. phosphoric acid production in 2014, 5.5 million pounds of U 3O 8 could have been recovered, more than domestic U.S. mine production of uranium in the same year. Annualized costs for a hypothetical uranium recovery plant are US$48-66 per pound U 3O 8 for solvent extraction, the process used historically in the United States to recover uranium from phosphoric acid. For ion exchange, not yet proven at a commercial scale for uranium recovery, the estimated costs are US$33-54 per pound U 3O 8. Our results suggest that it is technically possible for the United States to recover significant quantities of uranium from current phosphoric acid production. And for this type of uranium production to be economically attractive on a large scale, either recovery costs must fall or uranium prices rise.« less

Ionic Ckonductivity and Glass Transition of Phosphoric Acids

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

Wang, Yangyang; Lane, Nathan A; Sun, Che-Nan

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.

Ionic conductivity and glass transition of phosphoric acids

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

Wang, Yangyang; Lane, Nathan A; Sun, Che-Nan

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.

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.

Yellow phosphorus process to convert toxic chemicals to non-toxic products

DOEpatents

Chang, S.G.

1994-07-26

The present invention relates to a process for generating reactive species for destroying toxic chemicals. This process first contacts air or oxygen with aqueous emulsions of molten yellow phosphorus. This contact results in rapid production of abundant reactive species such as O, O[sub 3], PO, PO[sub 2], etc. A gaseous or liquid aqueous solution organic or inorganic chemicals is next contacted by these reactive species to reduce the concentration of toxic chemical and result in a non-toxic product. The final oxidation product of yellow phosphorus is phosphoric acid of a quality which can be recovered for commercial use. A process is developed such that the byproduct, phosphoric acid, is obtained without contamination of toxic species in liquids treated. A gas stream containing ozone without contamination of phosphorus containing species is also obtained in a simple and cost-effective manner. This process is demonstrated to be effective for destroying many types of toxic organic, or inorganic, compounds, including polychlorinated biphenyls (PCB), aromatic chlorides, amines, alcohols, acids, nitro aromatics, aliphatic chlorides, polynuclear aromatic compounds (PAH), dyes, pesticides, sulfides, hydroxyamines, ureas, dithionates and the like. 20 figs.

Yellow phosphorus process to convert toxic chemicals to non-toxic products

DOEpatents

Chang, Shih-Ger

1994-01-01

The present invention relates to a process for generating reactive species for destroying toxic chemicals. This process first contacts air or oxygen with aqueous emulsions of molten yellow phosphorus. This contact results in rapid production of abundant reactive species such as O, O.sub.3, PO, PO.sub.2, etc. A gaseous or liquid aqueous solution organic or inorganic chemicals is next contacted by these reactive species to reduce the concentration of toxic chemical and result in a non-toxic product. The final oxidation product of yellow phosphorus is phosphoric acid of a quality which can be recovered for commercial use. A process is developed such that the byproduct, phosphoric acid, is obtained without contamination of toxic species in liquids treated. A gas stream containing ozone without contamination of phosphorus containing species is also obtained in a simple and cost-effective manner. This process is demonstrated to be effective for destroying many types of toxic organic, or inorganic, compounds, including polychlorinated biphenyls (PCB), aromatic chlorides, amines, alcohols, acids, nitro aromatics, aliphatic chlorides, polynuclear aromatic compounds (PAH), dyes, pesticides, sulfides, hydroxyamines, ureas, dithionates and the like.

Preparation of elastic diglycolamic-acid modified chitosan sponges and their application to recycling of rare-earth from waste phosphor powder.

PubMed

Bai, Ruixi; Yang, Fan; Zhang, Yang; Zhao, Zhigang; Liao, Qiuxia; Chen, Peng; Zhao, Panpan; Guo, Wanghuan; Cai, Chunqing

2018-06-15

Inspired by the phenomenon of sponges soaking up water, a novel syringe-like adsorption device used diglycolamic-acid modified chitosan sponges (CSs-DGAA) as adsorbents is reported for recycling of rare-earth elements (REEs) by Squeezing & Soaking (S&S) operation. Integrating the elasticity of sponges and selective extraction ability of diglycolamic acid groups, the new device can efficiently recycle REEs from aqueous solutions. This device only needs 10 min to achieve adsorption equilibrium; squeezing the water from the sponges achieves solid-liquid separation. This syringe-like adsorption method not only solves the pollution problem caused by the organic solvents used during liquidliquid extractions, but also improves the time needed to achieve adsorption equilibrium and uses significantly less energy than energy intensive solid-phase extractions of solid-liquid separations. Moreover, the environment-friendly adsorbents effectively recycle yttrium and europium from waste phosphor powders. These experimental results demonstrated that the S&S method based on polymeric sponges has potential application in hydrometallurgy and environmental remediation. Copyright © 2018 Elsevier Ltd. All rights reserved.

SYNTHESIS OF MIXED FULL AND SEMIESTERS OF PHOSPHOROUS ACID AS ORGANIC MOTOR OIL ADDITIVES,

DTIC Science & Technology

The synthesis of mixed full and semiesters of phosphonic acid was effected using alkylphenols produced by the chemical industry. By condensation of...industrial alkylphenol or the condensation of acid chloride of di-(alkylphenyl)-phosphorous acid with diethylamine, the corresponding mixed full and semiesters

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. Copyright © 2014 Elsevier B.V. All rights reserved.

Modification of hydroxyapatite with ion-selective complexants: 1-hydroxyethane-1,1-diphosphonic acid

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

Daniels, Yasmine; Lyczko, Nathalie; Nzihou, Ange

Hydroxyapatite (HAP) was modified with 1-hydroxyethane-1,1-diphosphonic acid (HEDP), and its effect on divalent metal ion binding was determined. HAP was synthesized from calcium hydroxide and phosphoric acid. After calcination, it was modified with HEDP, and the influence of time and temperature on the modification was investigated. HEDP incorporation increased as its initial solution concentration increased from 0.01 to 0.50 M. Unmodified and modified HAP were characterized using Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, and specific surface area analysis. Ca/P ratios, acid capacities, and phosphorus elemental analyses gave the effect of modification on compositionmore » and surface characteristics. A high reaction temperature produced new phosphonate bands at 993, 1082, and 1144 cm –1 that indicated the presence of HEDP. HAP modification at a high temperature–long reaction time had the highest HEDP loading and gave the sharpest XRD peaks. The emergence of new HAP–HEDP strands was observed in SEM images for treated samples while EDS showed high phosphorus contents in these strands. Modified HAP had a high acid capacity from the additional P–OH groups in HEDP. The P(O)OH groups maintain their ability to bind metal ions within the HAP matrix: contacting the modified HAP with 10–4 N nitrate solutions of five transition metal ions gives an affinity sequence of Pb(II) > Cd(II) > Zn(II) > Ni(II) > Cu(II). Here, this result is comparable to that of commercially available di(2-ethylhexyl)phosphoric acid, a common solvent extractant, and the trend is consistent with the Misono softness parameter of metal ion polarizabilities.« less

Modification of hydroxyapatite with ion-selective complexants: 1-hydroxyethane-1,1-diphosphonic acid

DOE PAGES

Daniels, Yasmine; Lyczko, Nathalie; Nzihou, Ange; ...

2014-12-29

Hydroxyapatite (HAP) was modified with 1-hydroxyethane-1,1-diphosphonic acid (HEDP), and its effect on divalent metal ion binding was determined. HAP was synthesized from calcium hydroxide and phosphoric acid. After calcination, it was modified with HEDP, and the influence of time and temperature on the modification was investigated. HEDP incorporation increased as its initial solution concentration increased from 0.01 to 0.50 M. Unmodified and modified HAP were characterized using Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, and specific surface area analysis. Ca/P ratios, acid capacities, and phosphorus elemental analyses gave the effect of modification on compositionmore » and surface characteristics. A high reaction temperature produced new phosphonate bands at 993, 1082, and 1144 cm –1 that indicated the presence of HEDP. HAP modification at a high temperature–long reaction time had the highest HEDP loading and gave the sharpest XRD peaks. The emergence of new HAP–HEDP strands was observed in SEM images for treated samples while EDS showed high phosphorus contents in these strands. Modified HAP had a high acid capacity from the additional P–OH groups in HEDP. The P(O)OH groups maintain their ability to bind metal ions within the HAP matrix: contacting the modified HAP with 10–4 N nitrate solutions of five transition metal ions gives an affinity sequence of Pb(II) > Cd(II) > Zn(II) > Ni(II) > Cu(II). Here, this result is comparable to that of commercially available di(2-ethylhexyl)phosphoric acid, a common solvent extractant, and the trend is consistent with the Misono softness parameter of metal ion polarizabilities.« less

Friction modifier using adherent metallic multilayered or mixed element layer conversion coatings

NASA Technical Reports Server (NTRS)

Schramm, Harry F. (Inventor); Defalco, Frank G. (Inventor); Starks, Sr., Lloyd L. (Inventor)

2012-01-01

A process for creating conversion coatings and spin, drawing, and extrusion finishes for surfaces, wherein the conversion coatings and spin, drawing, and extrusion finishes contain potassium, phosphorus, nitrogen, silicon, and one or more non-alkaline metals. The process comprises forming a first aqueous solution of silicate, potassium hydroxide, and ammonium hydroxide; forming a second aqueous solution of water, phosphoric acid, ammonium hydroxide, an alkali metal hydroxide, and one or more non-alkaline metals, and then combining the first solution with the second solution to form a final solution. This final solution forms an anti-friction multi-layer conversion coating or a spin, drawing, and extrusion finish on a surface when applied to the surface, either directly or as an additive in lubricating fluids.

ANODIC TREATMENT OF URANIUM

DOEpatents

Kolodney, M.

1959-02-01

A method is presented for effecting eloctrolytic dissolution of a metallic uranium article at a uniform rate. The uranium is made the anode in an aqueous phosphoric acid solution containing nitrate ions furnished by either ammonium nitrate, lithium nitrate, sodium nitrate, or potassium nitrate. A stainless steel cathode is employed and electrolysls carried out at a current density of about 0.1 to 1 ampere per square inch.

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

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

Nuryadin, Bebeh W.; Pratiwi, Tripuspita; Faryuni, Irfana D.

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 bymore » 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.« less

Exterior Weathering Durability of Some Leach-Resistant Fire-Retardant Treatments for Wood Shingles: A Five-Year Report.

DTIC Science & Technology

1981-07-01

phos. Code 29 impregnation phonium chloride (90%. in water) 12.5.5%, sodium hydroxide 150%. in water) 2.16%, urea 2.06/%, a liquid melamine 4.35...1.08%.. dicyandlamide 4.54%. (9) impregnation formaldehyde (37%) 4.32%. phosphoric acid 7.06%. water $3.0%. UOFP_2 Pressure Treating solution: Urea 1.44...sodium hydroxide (500o in water) 0.8710, urea 0.800o. a liquid melamine 1.74°o, water 91.570 o. 29 Pressure impregnation Treating solution: Tetrakis

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.

The shear bond strength of self-adhesive resin cements to dentin and enamel: an in vitro study.

PubMed

Rodrigues, Raphaela F; Ramos, Carla M; Francisconi, Paulo A S; Borges, Ana Flávia S

2015-03-01

Clinicians continue to search for ways to simplify bonding procedures without compromising clinical efficacy. The purpose of this study was to evaluate the shear strength of self-adhesive cements RelyX U100 and RelyX U200, and conventional resin cement RelyX ARC to enamel and dentin after different surface treatments. The crowns of 120 bovine incisor teeth were separated from the roots and embedded in epoxy resin in polyvinyl chloride tubes. In each tooth, the area to be cemented was delimited with central holed adhesive tape. The teeth were distributed into 12 groups (n=10) according to the substrate; etched or not with 37% phosphoric acid; and cement type of enamel-U100, enamel-phosphoric acid-U100, enamel-U200, enamel-phosphoric acid-U200, enamel-ARC, enamel-phosphoric acid-ARC, dentin-U100, dentin-phosphoric acid-U100, dentin-U200, dentin-phosphoric acid-U200, dentin-ARC, and dentin-phosphoric acid-ARC. After 7 days of storage in artificial saliva, shear strength tests were performed by using a universal testing machine (0.5 mm/min). The data were analyzed with 3-way ANOVA and the Tukey test (α=.05). Fracture analysis was performed with a light microscope. Two specimens from each group were analyzed with a scanning electron microscope. In enamel, ARC (9.96 MPa) had higher shear strength (P=.038) than U100 (5.14 MPa); however, after surface etching, U100 (17.81 MPa) and U200 (17.52 MPa) had higher shear strength (P<.001). With dentin, no significant differences were observed (P=.999), except for dentin-ARC (0.34 MPa) (P=.001). Most fractures were of the adhesive type. U200 self-adhesive cement had similar bond strength to the ARC in enamel, but the combination with phosphoric acid had the best bond strength. For dentin, self-adhesive resin cements are equally effective alternatives to conventional resin cement. Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Friction Modifier Using Adherent Metallic Multilayered or Mixed Element Layer Conversion Coatings

NASA Technical Reports Server (NTRS)

Schramm, Harry F. (Inventor); Defalco, Francis G. (Inventor); Starks, Lloyd L., Sr. (Inventor)

2013-01-01

A process for creating conversion coatings and spin, drawing, and extrusion finishes for surfaces, wherein the conversion coatings and spin, drawing, and extrusion finishes contain potassium, phosphorus, nitrogen, and one or more non-alkaline metals and/or one or more metalloids. The process comprises forming an aqueous solution of water, phosphoric acid or sulfuric acid, ammonium hydroxide, an alkali metal hydroxide, and one or more non-alkaline metals and/or one or more metalloids. The aqueous solution forms an anti-friction multilayer conversion and/or mixed element coating or a spin, drawing, and extrusion finish on a surface when applied to the surface, either directly without the use of applied external electromotive force, or as an additive in lubricating fluids.

Fact Sheet - Phosphate Fertilizer Production Plants and Phosphoric Acid Manufacturing Plants NESHAP

EPA Pesticide Factsheets

Fact sheet summarizing National Emission Standards for Hazardous Air Pollutants (NESHAP) for Phosphate Fertilizer Production Plants and Phosphoric Acid Manufacturing Plants (40 CFR 63 Subparts AA and BB).

Effect of phosphoric acid on the morphology and tensile properties of halloysite-polyurethane composites

NASA Astrophysics Data System (ADS)

Gaaz, Tayser Sumer; Luaibi, Hasan Mohammed; Al-Amiery, Ahmed A.; Kadhum, Abdul Amir H.

2018-06-01

The high aspect ratio of nanoscale reinforcements enhances the tensile properties of pure polymer matrix. The composites were first made by adding halloysite nanotubes (HNTs) at low weight percentages of 1, 2, and 3 wt% to thermoplastic polyurethane (TPU). Then, HNTs were phosphoric acid-treated before adding to TPU at same weight percentage to create phosphoric acid HNTs-TPU composites. The samples were fabricated using injection moulding. The HNTs-TPU composites were characterized according to the tensile properties including tensile strength, tensile strain and Young's modulus. The loading has shown its highest tensile values at 2 wt% HNTs loading and same findings are shown with the samples that treated with phosphoric acid. The tensile strength increased to reach 24.65 MPa compare with the 17.7 MPa of the neat TPU showing about 26% improvement. For the phosphoric acid-treated composites, the improvement has reached 35% compared to the neat sample. Regarding the tensile stain, the improvement was about 83% at 2 wt% HNTs loading. For Young's modulus, the results obtained in this study have shown that Young's modulus is linearly improved with either the loading content or the phosphoric acid treated achieving its highest values at 3 wt% HNTs of 14.53 MPa and 16.27 MPa for untreated and treated, respectively. FESEM results showed that HNTs were well dispersed in TPU matrix. Thus, HNTs-TPU has improved tensile properties compared with pure TPU due to the addition of nanofiller.

40 CFR 63.605 - Monitoring requirements.

Code of Federal Regulations, 2013 CFR

2013-07-01

...) National Emission Standards for Hazardous Air Pollutants From Phosphoric Acid Manufacturing Plants § 63.605 Monitoring requirements. (a)(1) Each owner or operator of a new or existing wet-process phosphoric acid process line or superphosphoric acid process line subject to the provisions of this subpart shall install...

Two-Stage Separation of V(IV) and Al(III) by Crystallization and Solvent Extraction from Aluminum-Rich Sulfuric Acid Leaching Solution of Stone Coal

NASA Astrophysics Data System (ADS)

Shi, Qihua; Zhang, Yimin; Liu, Tao; Huang, Jing; Liu, Hong

2017-10-01

To improve separation of V(IV) and Al(III) from aluminum-rich sulfuric acid leaching solution of stone coal, the two-stage separation by crystallization and solvent extraction methods have been developed. A co-extraction coefficient ( k) was put forward to evaluate comprehensively co-extraction extent in different solutions. In the crystallization stage, 68.2% of aluminum can be removed from the solution. In the solvent extraction stage, vanadium was selectively extracted using di-2-ethylhexyl phosphoric acid/tri-n-butyl phosphate from the crystalline mother solution, followed by H2SO4 stripped efficiently. A V2O5 product with purity of 98.39% and only 0.10% Al was obtained after oxidation, precipitation, and calcination. Compared with vanadium extraction from solution without crystallization, the counter-current extraction stage of vanadium can be decreased from 6 to 3 and co-extraction coefficient ( k) decreased from 2.51 to 0.58 with two-stage separation. It is suggested that the aluminum removal by crystallization can evidently weaken the influence of aluminum co-extraction on vanadium extraction and improve the selectivity of solvent extraction for vanadium.

Driving forces and the influence of the buffer composition on the complexation reaction between ibuprofen and HPCD.

PubMed

Perlovich, German L; Skar, Merete; Bauer-Brandl, Annette

2003-10-01

Cyclodextrins are often used in order to increase the aqueous solubility of drug substances by complexation. In order to investigate the complexation reaction of ibuprofen and hydroxypropyl-beta-cyclodextrin, titration calorimetry was used as a direct method. The thermodynamic parameters of the complexation process (stability constant, K(11); complexation enthalpy, deltaH(c) degrees ) were obtained in two different buffer systems (citric acid/sodium-phosphate and phosphoric acid) at various pH values. Based on these data the relative contributions of the enthalpic and entropic terms of the Gibbs energy to the complexation process have been analyzed. In both buffers the enthalpic and entropic terms are of different sign and this case corresponds to a 'nonclassical' model of hydrophobic interaction. In citric buffer, the main driving force of complexation is the entropy, which increases from 60 to 67% while the pH of the solution increases from 3.2 to 8.0. However, for the phosphoric buffer the entropic term decreases from 60 to 45%, while the pH-value of the solution increases from 5.0 to 8.2, and the driving force of the complexation process changes from entropy to enthalpy. The experimental data of the present study are compared to results of other authors and discrepancies discussed in detail.

Method for improving the sedimentation and filterability of coal-derived liquids

DOEpatents

Katz, Sidney; Rodgers, Billy R.

1979-01-02

An improvement in the separation of suspended solids from coal-derived liquids by a separations process in which solids size is a separations parameter is achieved by contacting the coal-derived liquid containing suspended solids with an effective amount of an additive selected from the group of sulfuric acid, phosphoric acid, phosphoric anhydride and salts of sulfuric and phosphoric acid, and maintaining the contacted liquid at a temperature within the range of about 150.degree.-400.degree. C and for a time sufficient to achieve the desired separation rate.

Solubility Limits of Dibutyl Phosphoric Acid in Uranium Solutions at SRS

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

Thompson, M.C.; Pierce, R.A.; Ray, R.J.

1998-06-01

The Savannah River Site has enriched uranium (EU) solution which has been stored for almost 10 years since being purified in the second uranium cycle of the H area solvent extraction process. The concentrations in solution are {tilde 6} g/L U and about 0.1 M nitric acid. Residual tributylphosphate in the solutions has slowly hydrolyzed to form dibutyl phosphoric acid (HDBP) at concentrations averaging 50 mg/L. Uranium is known to form compounds with DBP which have limited solubility. The potential to form uranium-DBP solids raises a nuclear criticality safety issue. SRTC tests have shown that U-DBP solids will precipitate atmore » concentrations potentially attainable during storage of enriched uranium solutions. Evaporation of the existing EUS solution without additional acidification could result in the precipitation of U-DBP solids if DBP concentration in the resulting solution exceeds 110 ppm at ambient temperature. The same potential exists for evaporation of unwashed 1CU solutions. The most important variables of interest for present plant operations are HNO{sub 3} and DBP concentrations. Temperature is also an important variable controlling precipitation. The data obtained in these tests can be used to set operating and safety limits for the plant. It is recommended that the data for 0 degrees C with 0.5 M HNO{sub 3} be used for setting the limits. The limit would be 80 mg/L which is 3 standard deviations below the average of 86 observed in the tests. The data shows that super-saturation can occur when the DBP concentration is as much as 50 percent above the solubility limit. However, super-saturation cannot be relied on for maintaining nuclear criticality safety. The analytical method for determining DBP concentration in U solutions was improved so that analyses for a solution are accurate to within 10 percent. However, the overall uncertainty of results for periodic samples of the existing EUS solutions was only reduced slightly. Thus, sampling appears to be the largest portion of the uncertainty for EUS sample results, although the number of samples analyzed here is low which could contribution to higher uncertainty. The analytical method can be transferred to the plant analytical labs for more routine analysis of samples.« less

Synthesis and Photoluminescence Properties of Li2SrSiO4 Activated with Dy3+ and Sm3+

NASA Astrophysics Data System (ADS)

Erdoğmuş, E.

2015-01-01

Li2SrSiO4:M (M: Dy3+ and Sm3+) phosphors were synthesized by the conventional solid state reaction. The synthesized materials were characterized by powder XRD. The emission and excitation spectra of these phosphors were measured at room temperature with a spectrofluorometer. The first phosphor, Li2SrSiO4:Dy3+, emits at 479, 573, and 666 nm upon 351 nm excitation. The second phosphor, Li2SrSiO4:Sm3+, emits at 561-571, 594, 647-655, and 703-713 nm upon 399 nm excitation. Also, the dependence of the photoluminescence properties of both phosphors on boric acid concentration was investigated. The results showed that boric acid was effective in improving the photoluminescence intensity of both phosphors.

PLUTONIUM PURIFICATION PROCESS EMPLOYING THORIUM PYROPHOSPHATE CARRIER

DOEpatents

King, E.L.

1959-04-28

The separation and purification of plutonium from the radioactive elements of lower atomic weight is described. The process of this invention comprises forming a 0.5 to 2 M aqueous acidffc solution containing plutonium fons in the tetravalent state and elements with which it is normally contaminated in neutron irradiated uranium, treating the solution with a double thorium compound and a soluble pyrophosphate compound (Na/sub 4/P/sub 2/O/sub 7/) whereby a carrier precipitate of thorium A method is presented of reducing neptunium and - trite is advantageous since it destroys any hydrazine f so that they can be removed from solutions in which they are contained is described. In the carrier precipitation process for the separation of plutonium from uranium and fission products including zirconium and columbium, the precipitated blsmuth phosphate carries some zirconium, columbium, and uranium impurities. According to the invention such impurities can be complexed and removed by dissolving the contaminated carrier precipitate in 10M nitric acid, followed by addition of fluosilicic acid to about 1M, diluting the solution to about 1M in nitric acid, and then adding phosphoric acid to re-precipitate bismuth phosphate carrying plutonium.

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

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 an...

Influence of multi-step washing using Na2EDTA, oxalic acid and phosphoric acid on metal fractionation and spectroscopy characteristics from contaminated soil.

PubMed

Wei, Meng; Chen, Jiajun

2016-11-01

A multi-step soil washing test using a typical chelating agent (Na 2 EDTA), organic acid (oxalic acid), and inorganic weak acid (phosphoric acid) was conducted to remediate soil contaminated with heavy metals near an arsenic mining area. The aim of the test was to improve the heavy metal removal efficiency and investigate its influence on metal fractionation and the spectroscopy characteristics of contaminated soil. The results indicated that the orders of the multi-step washing were critical for the removal efficiencies of the metal fractions, bioavailability, and potential mobility due to the different dissolution levels of mineral fractions and the inter-transformation of metal fractions by XRD and FT-IR spectral analyses. The optimal soil washing options were identified as the Na 2 EDTA-phosphoric-oxalic acid (EPO) and phosphoric-oxalic acid-Na 2 EDTA (POE) sequences because of their high removal efficiencies (approximately 45 % for arsenic and 88 % for cadmium) and the minimal harmful effects that were determined by the mobility and bioavailability of the remaining heavy metals based on the metal stability (I R ) and modified redistribution index ([Formula: see text]).

Effect of EDTA and phosphoric Acid pretreatment on the bonding effectiveness of self-etch adhesives to ground enamel.

PubMed

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

2010-10-01

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. 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). 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. Use of phosphoric acid pretreatment can be beneficial with mild self-etching adhesive systems for bonding to enamel.

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

40 CFR 63.602 - Standards for existing sources.

Code of Federal Regulations, 2012 CFR

2012-07-01

...) National Emission Standards for Hazardous Air Pollutants From Phosphoric Acid Manufacturing Plants § 63.602 Standards for existing sources. (a) Wet process phosphoric acid process line. On and after the date on which... of equivalent P2O5 feed (0.020 lb/ton). (b) Superphosphoric acid process line—(1) Vacuum evaporation...

40 CFR 63.602 - Standards for existing sources.

Code of Federal Regulations, 2014 CFR

2014-07-01

...) National Emission Standards for Hazardous Air Pollutants From Phosphoric Acid Manufacturing Plants § 63.602 Standards for existing sources. (a) Wet process phosphoric acid process line. On and after the date on which... of equivalent P2O5 feed (0.020 lb/ton). (b) Superphosphoric acid process line—(1) Vacuum evaporation...

40 CFR 63.602 - Standards for existing sources.

Code of Federal Regulations, 2013 CFR

2013-07-01

...) National Emission Standards for Hazardous Air Pollutants From Phosphoric Acid Manufacturing Plants § 63.602 Standards for existing sources. (a) Wet process phosphoric acid process line. On and after the date on which... of equivalent P2O5 feed (0.020 lb/ton). (b) Superphosphoric acid process line—(1) Vacuum evaporation...

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

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

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.

Method for stabilizing low-level mixed wastes at room temperature

DOEpatents

Wagh, A.S.; Singh, D.

1997-07-08

A method to stabilize solid and liquid waste at room temperature is provided comprising combining solid waste with a starter oxide to obtain a powder, contacting the powder with an acid solution to create a slurry, said acid solution containing the liquid waste, shaping the now-mixed slurry into a predetermined form, and allowing the now-formed slurry to set. The invention also provides for a method to encapsulate and stabilize waste containing cesium comprising combining the waste with Zr(OH){sub 4} to create a solid-phase mixture, mixing phosphoric acid with the solid-phase mixture to create a slurry, subjecting the slurry to pressure; and allowing the now pressurized slurry to set. Lastly, the invention provides for a method to stabilize liquid waste, comprising supplying a powder containing magnesium, sodium and phosphate in predetermined proportions, mixing said powder with the liquid waste, such as tritium, and allowing the resulting slurry to set. 4 figs.

Method for stabilizing low-level mixed wastes at room temperature

DOEpatents

Wagh, Arun S.; Singh, Dileep

1997-01-01

A method to stabilize solid and liquid waste at room temperature is provided comprising combining solid waste with a starter oxide to obtain a powder, contacting the powder with an acid solution to create a slurry, said acid solution containing the liquid waste, shaping the now-mixed slurry into a predetermined form, and allowing the now-formed slurry to set. The invention also provides for a method to encapsulate and stabilize waste containing cesium comprising combining the waste with Zr(OH).sub.4 to create a solid-phase mixture, mixing phosphoric acid with the solid-phase mixture to create a slurry, subjecting the slurry to pressure; and allowing the now pressurized slurry to set. Lastly, the invention provides for a method to stabilize liquid waste, comprising supplying a powder containing magnesium, sodium and phosphate in predetermined proportions, mixing said powder with the liquid waste, such as tritium, and allowing the resulting slurry to set.

The TRUSPEAK Concept: Combining CMPO and HDEHP for Separating Trivalent Lanthanides from the Transuranic Elements

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

Lumetta, Gregg J.; Gelis, Artem V.; Braley, Jenifer C.

2013-04-08

Combining octyl(phenyl)-N,N-diisobutyl-carbamoylmethyl-phosphine oxide (CMPO) and bis-(2-ethylhexyl) phosphoric acid (HDEHP) into a single process solvent for separating transuranic elements from liquid high-level waste is explored. Co-extraction of americium and the lanthanide elements from nitric acid solution is possible with a solvent mixture consisting of 0.1-M CMPO plus 1-M HDEHP in n-dodecane. Switching the aqueous-phase chemistry to a citrate-buffered solution of diethylene triamine pentaacetic acid (DTPA) allows for selective stripping of americium, separating it from the lanthanide elements. Potential strategies for managing molybdenum and zirconium (both of which co-extract with americium and the lanthanides) have been developed. The work presented here demonstratesmore » the feasibility of combining CMPO and HDEHP into a single extraction solvent for recovering americium from high-level waste and its separation from the lanthanides.« less

Hybrid Calcium Phosphate Coatings for Titanium Implants

NASA Astrophysics Data System (ADS)

Kharapudchenko, E.; Ignatov, V.; Ivanov, V.; Tverdokhlebov, S.

2017-01-01

Hybrid multilayer coatings were obtained on titanium substrates by the combination of two methods: the micro-arc oxidation in phosphoric acid solution with the addition of calcium compounds to high supersaturated state and RF magnetron sputtering of the target made of synthetic hydroxyapatite. 16 different groups of coatings were formed on titanium substrates and in vitro studies were conducted in accordance with ISO 23317 in the solution simulating body fluid. The studies using SEM, XRD of the coatings of the samples before and after exposure to SBF were performed. The features of morphology, chemical and phase composition of the studied coatings are shown.

Corrosion resistant properties of polyaniline acrylic coating on magnesium alloy

NASA Astrophysics Data System (ADS)

Sathiyanarayanan, S.; Azim, S. Syed; Venkatachari, G.

2006-12-01

The performance of the paint coating based on acrylic-polyaniline on magnesium alloy ZM 21 has been studied by electrochemical impedance spectroscopy in 0.5% NaCl solution. The polyaniline was prepared by chemical oxidative method of aniline with ammonium persulphate in phosphoric acid medium. The phosphate-doped polyaniline was characterized by FTIR and XRD methods. Acrylic paint containing the phosphate-doped polyaniline was prepared and coated on magnesium ZM 21 alloy. The coating was able to protect the magnesium alloy and no base metal dissolution was noted even after 75 days exposure to sodium chloride solution.

Enantioselective Synthesis of α-Mercapto-β-amino Esters via Rh(II)/Chiral Phosphoric Acid-Cocatalyzed Three-Component Reaction of Diazo Compounds, Thiols, and Imines.

PubMed

Xiao, Guolan; Ma, Chaoqun; Xing, Dong; Hu, Wenhao

2016-12-02

An enantioselective method for the synthesis of α-mercapto-β-amino esters has been developed via a rhodium(II)/chiral phosphoric acid-cocatalyzed three-component reaction of diazo compounds, thiols, and imines. This transformation is proposed to proceed through enantioselective trapping of the sulfonium ylide intermediate generated in situ from the diazo compound and thiol by the phosphoric acid-activated imine. With this method, a series of α-mercapto-β-amino esters were obtained in good yields with moderate to good stereoselectivities.

Temperature dependence and P/Ti ratio in phosphoric acid treatment of titanium dioxide and powder properties.

PubMed

Onoda, H; Matsukura, A

2015-02-01

Titanium dioxide has photocatalytic activity and 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 dioxide was shaken with phosphoric acid to synthesize a white pigment for cosmetics. Titanium dioxide was treated with 0.1 mol/L of phosphoric acid at various P/Ti molar ratios, and then shaken in hot water for 1 h. The chemical composition, powder properties, photocatalytic activity, colour phase, and smoothness of the obtained powder were studied. The obtained materials indicated XRD peaks of titanium dioxide, however the peaks diminished subsequent to phosphoric acid treatment. The samples included small particles with sub-micrometer size. The photocatalytic activity of the obtained powders decreased, decomposing less sebum on the skin. Samples prepared at high P/Ti ratio with high shaking temperature indicated low whiteness in in L*a*b* colour space. The shaking and heating temperature and P/Ti ratio had influence on the smoothness of the obtained materials. Phosphoric acid treatment of titanium dioxide is an effective method to inhibit photocatalytic activity for a white pigment. © 2014 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

Ion conduction mechanisms and thermal properties of hydrated and anhydrous phosphoric acids studied with 1H, 2H, and 31P NMR.

PubMed

Aihara, Yuichi; Sonai, Atsuo; Hattori, Mineyuki; Hayamizu, Kikuko

2006-12-14

To understand the behaviors of phosphoric acids in fuel cells, the ion conduction mechanisms of phosphoric acids in condensed states without free water and in a monomer state with water were studied by measuring the ionic conductivity (sigma) using AC impedance, thermal properties, and self-diffusion coefficients (D) and spin-lattice relaxation times (T1) with multinuclear NMR. The self-diffusion coefficient of the protons (H+ or H3O+), H2O, and H located around the phosphate were always larger than the diffusion coefficients of the phosphates and the disparity increased with increasing phosphate concentration. The diffusion coefficients of the samples containing D2O paralleled those in the protonated samples. Since the 1H NMR T1 values exhibited a minimum with temperature, it was possible to determine the correlation times and they were found to be of nanosecond order for a distance of nanometer order for a flip. The agreement of the ionic conductivities measured directly and those calculated from the diffusion coefficients indicates that the ion conduction obeys the Nernst-Einstein equation in the condensed phosphoric acids. The proton diffusion plays a dominant role in the ion conduction, especially in the condensed phosphoric acids.

A new halogen-free chemical oscillator: the reaction between permanganate ion and ninhydrin in a continuously stirred tank reactor

NASA Astrophysics Data System (ADS)

Treindl, Ľudovít; Nagy, Arpád

1987-07-01

The reaction between permanganate ion and ninhydrin in the presence of phosphoric acid in aqueous solution shows sustained oscillations in a continuously stirred tank reactor (CSTR). It exhibits a kinetic bistability between an oscillatory and a stationary state. Our new oscillating system seems to be a second permanganate chemical oscillator, thus broadening the small group of non-halogen-based chemical oscillators.

SPECTROPHOTOMETRIC DETERMINATION OF TRACES OF BORON IN THORIUM

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

Onishi, H.; Ishiwatari, N.; Nagai, H.

1960-12-01

A procedure is described for the spectrophotometric determination of a few tenths of a pant per million of boron ia thorium oxide or thorium. The sample is dissolved in strong phosphoric acid. After diluting the solution with water, boron is separated by distillation as methyl borate and finally determined by the curcumin method. The error is not likely to exceed plus or minus O.l ppm for 0.2 to 1 ppm of boron. (auth)

Implant decontamination with phosphoric acid during surgical peri-implantitis treatment: a RCT.

PubMed

Hentenaar, Diederik F M; De Waal, Yvonne C M; Strooker, Hans; Meijer, Henny J A; Van Winkelhoff, Arie-Jan; Raghoebar, Gerry M

2017-12-01

Peri-implantitis is known as an infectious disease that affects the peri-implant soft and hard tissue. Today, scientific literature provides very little evidence for an effective intervention protocol for treatment of peri-implantitis. The aim of the present randomized controlled trial is to evaluate the microbiological and clinical effectiveness of phosphoric acid as a decontaminating agent of the implant surface during surgical peri-implantitis treatment. Peri-implantitis lesions were treated with resective surgical treatment aimed at peri-implant granulation tissue removal, bone recontouring, and pocket elimination. Fifty-three implant surfaces in 28 patients were mechanically cleaned and treated with either 35% phosphoric etching gel (test group) or sterile saline (control group). Microbiological samples were obtained during surgery; clinical parameters were recorded at baseline and at 3 months after treatment. Data were analyzed using multi-variable linear regression analysis and multilevel statistics. Significant immediate reductions in total anaerobic bacterial counts on the implant surface were found in both groups. Immediate reduction was greater when phosphoric acid was used. The difference in log-transformed mean anaerobic counts between both procedures was not statistical significant (p = 0.108), but there were significantly less culture-positive implants after the decontamination procedure in the phosphoric acid group (p = 0.042). At 3 months post-surgery, 75% of the implants in the control group and 63.3% of the implants in the test group showed disease resolution. However, no significant differences in clinical and microbiological outcomes between both groups were found. The application of 35% phosphoric acid after mechanical debridement is superior to mechanical debridement combined with sterile saline rinsing for decontamination of the implant surface during surgical peri-implantitis treatment. However, phosphoric acid as implant surface decontaminant does not seem to enhance clinical outcomes on a 3-month follow-up. Netherlands National Trial Register, NTR5185 (www.trialregister.nl).

40 CFR 63.603 - Standards for new sources.

Code of Federal Regulations, 2012 CFR

2012-07-01

...) National Emission Standards for Hazardous Air Pollutants From Phosphoric Acid Manufacturing Plants § 63.603 Standards for new sources. (a) Wet process phosphoric acid process line. On and after the date on which the... equivalent P2O5 feed (0.01350 lb/ton). (b) Superphosphoric acid process line. On and after the date on which...

40 CFR 63.603 - Standards for new sources.

Code of Federal Regulations, 2014 CFR

2014-07-01

...) National Emission Standards for Hazardous Air Pollutants From Phosphoric Acid Manufacturing Plants § 63.603 Standards for new sources. (a) Wet process phosphoric acid process line. On and after the date on which the... equivalent P2O5 feed (0.01350 lb/ton). (b) Superphosphoric acid process line. On and after the date on which...

40 CFR 63.603 - Standards for new sources.

Code of Federal Regulations, 2013 CFR

2013-07-01

...) National Emission Standards for Hazardous Air Pollutants From Phosphoric Acid Manufacturing Plants § 63.603 Standards for new sources. (a) Wet process phosphoric acid process line. On and after the date on which the... equivalent P2O5 feed (0.01350 lb/ton). (b) Superphosphoric acid process line. On and after the date on which...

Structural Characterization of the Degradation Products of a Minor Natural Sweet Diterpene Glycoside Rebaudioside M under Acidic Conditions

PubMed Central

Prakash, Indra; Chaturvedula, Venkata Sai Prakash; Markosyan, Avetik

2014-01-01

Degradation of rebaudioside M, a minor sweet component of Stevia rebaudiana Bertoni, under conditions that simulated extreme pH and temperature conditions has been studied. Thus, rebaudioside M was treated with 0.1 M phosphoric acid solution (pH 2.0) and 80 °C temperature for 24 h. Experimental results indicated that rebaudioside M under low pH and higher temperature yielded three minor degradation compounds, whose structural characterization was performed on the basis of 1D (1H-, 13C-) & 2D (COSY, HSQC, HMBC) NMR, HRMS, MS/MS spectral data as well as enzymatic and acid hydrolysis studies. PMID:24424316

The use of phosphoric acid to stiffen hot mix asphalt binders

DOT National Transportation Integrated Search

2014-11-01

This document offers guidelines for the use of phosphoric acid to stiffen asphalt binders for hot mix paving applications. Data are presented on the likely effect on pavement life, moisture resistance, and use with limestone aggregates and liquid ami...

Scanning electron microscopy evaluation of the effect of etching agents on human enamel surface.

PubMed

Zanet, Caio G; Arana-Chavez, Victor E; Fava, Marcelo

2006-01-01

Acid etching promotes microporosities on enamel surface, which provide a better bonding surface to adhesive materials. The purpose of this study was to comparatively analyze the microstructure of enamel surface after etching with 37% phosphoric acid or with two self-etching primers, Non-rinse conditioner (NRC) and Clearfil SE Bond (CSEB) using scanning electron microscopy. Thirty sound premolars were divided into 3 groups with ten teeth each: Group 1: the buccal surface was etched with 37% phosphoric acid for 15 seconds; Group 2: the buccal surface was etched with NRC for 20 seconds; Group 3: the buccal surface was etched with CSEB for 20 seconds. Teeth from Group 1 were rinsed with water; teeth from all groups were air-dried for 15 seconds. After that, all specimens were processed for scanning electron microscopy and analyzed in a Jeol 6100 SEM. The results showed deeper etching when the enamel surface was etched with 37% phosphoric acid, followed by NRC and CSEB. It is concluded that 37% phosphoric acid is still the best agent for a most effective enamel etching.

40 CFR 98.266 - Data reporting requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... phosphoric acid process lines. (8) Number of times missing data procedures were used to estimate phosphate... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Data reporting requirements. 98.266... (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Phosphoric Acid Production § 98.266 Data reporting...

40 CFR 98.266 - Data reporting requirements.

Code of Federal Regulations, 2014 CFR

2014-07-01

... wet-process phosphoric acid process lines. (8) Number of times missing data procedures were used to... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Data reporting requirements. 98.266... (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Phosphoric Acid Production § 98.266 Data reporting...

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

Hurtubise, R.J.

Interaction models were developed for moisture effects on room-temperature fluorescence (RTF) and room-temperature phosphorescence (RTP) of compounds adsorbed on filter paper. The models described both dynamic and matrix quenching and also related the Young modulus of filter paper to quenching of phosphor on moist filter paper. Photophysical parameters for lumiphors in solution and on solid matrices were compared. Results showed that for some compounds, solid-matrix luminescence has greater analytical potential than solution luminescence. Also, the solid-matrix systems into one of two categories depending on how the intersystem crossing rate constants change with temperature. The first study was carried out onmore » effects of heavy atom on solid-matrix luminescence. With some heavy atoms, maximum solid-matrix phosphorescence quantum yield was obtained at room temperature, and there was no need to use low temperature to obtain a strong phosphorescence signal. By studying solid-matrix luminescence properties of phosphors adsorbed on sodium acetate and deuterated sodium acetate, an interaction model was developed for p-aminobenzoic acid anion adsorbed on sodium acetate. It was shown that the energy-gap law was applicable to solid-matrix luminescence. Also, deuterated phenanthrene and undeuterated phenanthrene were used to study nonradiative transition of excited triplet state of adsorbed phosphors. Heat capacities of several solid matrices were obtained vs temperature and related to vibrational coupling of solid matrix with phosphor. Photophysical study was performed on the hydrolysis products of benzo(a)pyrene-DNA adducts. Also, an analytical method was developed for tetrols in human lung fractions. Work was initiated on the formation of room temperature glasses with glucose and trehalose. Also, work has begun for the development of an oxygen sensor by measuring the RTP quenching of triphenylene on filter paper.« less

Effect of Phosphoric Acid Pre-etching on Fatigue Limits of Self-etching Adhesives.

PubMed

Takamizawa, T; Barkmeier, W W; Tsujimoto, A; Scheidel, D D; Erickson, R L; Latta, M A; Miyazaki, M

2015-01-01

The purpose of this study was to use shear bond strength (SBS) and shear fatigue limit (SFL) testing to determine the effect of phosphoric acid pre-etching of enamel and dentin prior to application of self-etch adhesives for bonding resin composite to these substrates. Three self-etch adhesives--1) G- ænial Bond (GC Corporation, Tokyo, Japan); 2) OptiBond XTR (Kerr Corp, Orange, CA, USA); and 3) Scotchbond Universal (3M ESPE Dental Products, St Paul, MN, USA)--were used to bond Z100 Restorative resin composite to enamel and dentin surfaces. A stainless-steel metal ring with an inner diameter of 2.4 mm was used to bond the resin composite to flat-ground (4000 grit) tooth surfaces for determination of both SBS and SFL. Fifteen specimens each were used to determine initial SBS to human enamel/dentin, with and without pre-etching with a 35% phosphoric acid (Ultra-Etch, Ultradent Products Inc, South Jordan, UT, USA) for 15 seconds prior to the application of the adhesives. A staircase method of fatigue testing (25 specimens for each test) was then used to determine the SFL of resin composite bonded to enamel/dentin using a frequency of 10 Hz for 50,000 cycles or until failure occurred. A two-way analysis of variance and Tukey post hoc test were used for analysis of SBS data, and a modified t-test with Bonferroni correction was used for the SFL data. Scanning electron microscopy was used to examine the area of the bonded restorative/tooth interface. For all three adhesive systems, phosphoric acid pre-etching of enamel demonstrated significantly higher (p<0.05) SBS and SFL with pre-etching than it did without pre-etching. The SBS and SFL of dentin bonds decreased with phosphoric acid pre-etching. The SBS and SFL of bonds using phosphoric acid prior to application of self-etching adhesives clearly demonstrated different tendencies between enamel and dentin. The effect of using phosphoric acid, prior to the application of the self-etching adhesives, on SBS and SFL was dependent on the adhesive material and tooth substrate and should be carefully considered in clinical situations.

Molten-salt synthesis and composition-dependent luminescent properties of barium tungsto-molybdate-based solid solution phosphors

NASA Astrophysics Data System (ADS)

Xiang-Hong, He; Zhao-Lian, Ye; Ming-Yun, Guan; Ning, Lian; Jian-Hua, Sun

2016-02-01

Pr3+-activated barium tungsto-molybdate solid solution phosphor Ba(Mo1-zWz)O4:Pr3+ is successfully fabricated via a facile molten-salt approach. The as-synthesized microcrystal is of truncated octahedron and exhibits deep-red-emitting upon blue light excitation. Powder x-ray diffraction and Raman spectroscopy techniques are utilized to investigate the formation of solid solution phosphor. The luminescence behaviors depend on the resulting composition of the microcrystals with fixed Pr3+-doping concentration, while the host lattices remain in a scheelite structure. The forming solid solution via the substitution of [WO4] for [MoO4] can significantly enhance its luminescence, which may be due to the fact that Ba(Mo1-zWz)O4:Pr3+ owns well-defined facets and uniform morphologies. Owing to its properties of high phase purity, well-defined facets, highly uniform morphologies, exceptional chemical and thermal stabilities, and stronger emission intensity, the resulting solid solution phosphor is expected to find potential applications in phosphor-converted white light-emitting diodes (LEDs). Project supported by the Construction Fund for Science and Technology Innovation Group from Jiangsu University of Technology, China, the Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, China (Grant No. KHK1409), the Priority Academic Program Development of Jiangsu Higher Education Institutions, China, and the National Natural Science Foundation of China (Grant No. 21373103).

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.

40 CFR 98.267 - Records that must be retained.

Code of Federal Regulations, 2014 CFR

2014-07-01

... (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Phosphoric Acid Production § 98.267 Records that must be... paragraphs (a) through (c) of this section for each wet-process phosphoric acid production facility. (a.../or deliveries (if vertically integrated with a mine). (c) Documentation of the procedures used to...

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.

A promising red-emitting phosphor for white-light-emitting diodes prepared by a modified solid-state reaction

NASA Astrophysics Data System (ADS)

Ren, Fuqiang; Chen, Donghua

2010-02-01

Using urea, boric acid and polyethylene glycol (PEG) as auxiliary reagents, the novel red-emitting phosphors Ca 19Zn 2 (PO 4) 14:Eu 3+ have been successfully synthesized by a modified solid-state reaction. Thermogravimetric (TG) analysis, X-ray diffraction (XRD), transmission electron microscopy (TEM) and photoluminescence (PL) spectra were used to characterize the resulting phosphors. The dependence of the photoluminescence properties of Ca 19Zn 2 (PO 4) 14:Eu 3+ phosphors upon urea, boric acid and PEG concentration and the quadric-sintered temperature were investigated. Luminescent measurements showed that the phosphors can be efficiently excited by ultraviolet (UV) to visible region, emitting a red light with a peak wavelength of 616 nm. The material has potential application as a fluorescent material for ultraviolet light-emitting diodes (UV-LEDs).

Spent coffee grounds-based activated carbon preparation for sequestering of malachite green

NASA Astrophysics Data System (ADS)

Lim, Jun-Wei; Lam, Keat-Ying; Bashir, Mohammed J. K.; Yeong, Yin-Fong; Lam, Man-Kee; Ho, Yeek-Chia

2016-11-01

The key of reported work was to optimize the fabricating factors of spent coffee grounds-based activated carbon (SCG-bAC) used to sequester Malachite Green (MG) form aqueous solution via adsorption process. The fabricating factors of impregnation ratio with ortho-phosphoric acid, activation temperature and activation time were simultaneously optimized by central composite design (CCD) of response surface methodology (RSM) targeting on maximum removal of MG. At the optimum condition, 96.3% of MG was successfully removed by SCG-bAC at the impregnation ratio with ortho-phosphoric acid of 0.50, activation temperature of 554°C and activation time of 31.4 min. Statistical model that could predict the MG removal percentage was also derived and had been statistically confirmed to be significant. Subsequently, the MG adsorption equilibrium data was found well-fitted to Langmuir isotherm model, indicating the predominance of monolayer adsorption of MG on SCG-bAC surface. To conclude, the findings from the this study unveil the potential of spent coffee grounds as an alternative precursor in fabricating low-cost AC for the treatment of wastewater loaded with MG pollutant.

Effect of a New Surface Treatment Solution on the Bond Strength of Composite to Enamel

DTIC Science & Technology

2016-06-01

enamel ( Erickson et al., 2005). More significantly, clinical studies have shown significantly less marginal defects and staining with selective...using phosphoric acid. Erickson et al., (2009) also found improved bond strengths with a selective-etch step and attributed this to the degree of...cut enamel and dentin. Oper Dent 2005;30(1):39-49. Erickson RL, Barkmeier WW, Kimmes NS. Bond strength of self-etch adhesives to pre-etched

Activated carbons from potato peels: The role of activation agent and carbonization temperature of biomass on their use as sorbents for bisphenol A uptake from aqueous solutions

NASA Astrophysics Data System (ADS)

Arampatzidou, An; Deliyanni, Eleni A.

2015-04-01

Activated carbons prepared from potato peels, a solid waste by product, and activated with different activating chemicals, have been studied for the adsorption of an endocrine disruptor (Bisphenol-A) from aqueous solutions. The potato peels biomass was activated with phosphoric acid, KOH and ZnCl2. The different activating chemicals were tested in order the better activation agent to be found. The carbons were carbonized by pyrolysis, in one step procedure, at three different temperatures in order the role of the temperature of carbonization to be pointed out. The porous texture and the surface chemistry of the prepared activated carbons were characterized by Nitrogen adsorption (BET), Scanning Electron Microscope (SEM), thermal analysis (DTA) and Fourier Transform Infrared Spectroscopy (FTIR). Batch experiments were performed to investigate the effect of pH, the adsorbent dose, the initial bisphenol A concentration and temperature. Equilibrium adsorption data were analyzed by Langmuir and Freundlich isotherms. The thermodynamic parameters such as the change of enthalpy (ΔH0), entropy (ΔS0) and Gibb's free energy (ΔG0) of adsorption systems were also evaluated. The adsorption capacity calculated from the Langmuir isotherm was found to be 450 mg g-1 at an initial pH 3 at 25 °C for the phosphoric acid activated carbon, that make the activated carbon a promising adsorbent material.

Activated carbon from peach stones using phosphoric acid activation at medium temperatures.

PubMed

Kim, Dong-Su

2004-01-01

In the present study, the activation features of phosphoric acid have been investigated using waste peach stones as the raw material in the production of granular activated carbon. Thermogravimetry/differential thermal analysis was conducted to characterize the thermal behavior of peach stone and titration method was used to evaluate the adsorption capacity of the produced activated carbon. It was observed that the iodine value of the activated carbon increased with activation temperature. However, temperatures higher than 500 degrees C caused a thermal destruction, which resulted in the decrease of the adsorption capacity. Activation longer than 1.5 h at 500 degrees C resulted in thermal degradation of the porous structure of the activated carbon. The adsorption capacity was enhanced with increasing of amounts of phosphoric acid, however, excessive phosphoric acid caused a decrease in the iodine value. In addition, it was found that the carbon yields generally decreased with activation temperature and activation time. Scanning electron microscopy analysis was conducted to observe the changes in the poros structure of the activated carbon produced in different temperatures. Activation of carbon by phosphoric acid was found to be superior to that by CaCl2 and gas activation. The activated carbon produced from peach stone was applied as an adsorbent in the treatment of synthesized wastewater containing cadmium ion and its adsorption capacity was found to be as good as that of the commercial one.

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.

Combustion synthesis and luminescence properties of yellow-emitting phosphors Ca{sub 2}BO{sub 3}Cl:Eu{sup 2+}

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

Xia, Zhiguo, E-mail: xiazg426@yahoo.com.cn; Liao, Libing, E-mail: lbliao@cugb.edu.cn; Zhang, Zepeng

2012-02-15

Graphical abstract: A yellow-emitting phosphor Ca{sub 2}BO{sub 3}Cl:Eu{sup 2+} was firstly synthesized by the solution-combustion method. The photoluminescence excitation and emission spectra, temperature dependence of luminescence intensity, and luminescence lifetime of the phosphor were investigated. Highlights: Black-Right-Pointing-Pointer Ca{sub 2}BO{sub 3}Cl:Eu{sup 2+} phosphor was synthesized by a solution-combustion method. Black-Right-Pointing-Pointer Ca{sub 2}BO{sub 3}Cl:Eu{sup 2+} showed an intense yellow emission band centered at 569 nm with the CIE coordinate of (0.453, 0.526). Black-Right-Pointing-Pointer The temperature dependent luminescence property and mechanism of Ca{sub 2}BO{sub 3}Cl:Eu{sup 2+} were studied. -- Abstract: Yellow-emitting phosphor Ca{sub 2}BO{sub 3}Cl:Eu{sup 2+} was synthesized by a solution-combustion method. Themore » phase structure and microstructure were determined by the X-ray diffraction (XRD) and scanning electron microscope (SEM) analysis, respectively. The as-prepared Ca{sub 2}BO{sub 3}Cl:Eu{sup 2+} phosphor absorbed near ultraviolet and blue light of 320-500 nm, and showed an intense yellow emission band centered at 569 nm with the CIE coordinate of (0.453, 0.526). The lifetime of Eu{sup 2+} ions in Ca{sub 2}BO{sub 3}Cl:Eu{sup 2+} phosphor was measured, furthermore the temperature dependent luminescence property and mechanism were studied, which also testified that the present phosphor had a promising potential for white light-emitting diodes.« less

Chromatographic retention prediction and octanol-water partition coefficient determination of monobasic weak acidic compounds in ion-suppression reversed-phase liquid chromatography using acids as ion-suppressors.

PubMed

Ming, Xin; Han, Shu-ying; Qi, Zheng-chun; Sheng, Dong; Lian, Hong-zhen

2009-08-15

Although simple acids, replacing buffers, have been widely applied to suppress the ionization of weakly ionizable acidic analytes in reversed-phase liquid chromatography (RPLC), none of the previously reported works focused on the systematic studies about the retention behavior of the acidic solutes in this ion-suppression RPLC mode. The subject of this paper was therefore to investigate the retention behavior of monobasic weak acidic compounds using acetic, perchloric and phosphoric acids as the ion-suppressors. The apparent octanol-water partition coefficient (K" ow) was proposed to calibrate the octanol-water partition coefficient (K(ow)) of these weak acidic compounds, which resulted in a better linear correlation with log k(w), the logarithm of the hypothetical retention factor corresponding to neat aqueous fraction of hydroorganic mobile phase. This log K" ow-log k w linear correlation was successfully validated by the results of monocarboxylic acids and monohydrating phenols, and moreover by the results under diverse experimental conditions for the same solutes. This straightforward relationship not only can be used to effectively predict the retention values of weak acidic solutes combined with Snyder-Soczewinski equation, but also can offer a promising medium for directly measuring K(ow) data of these compounds via Collander equation. In addition, the influence of the different ion-suppressors on the retention of weak acidic compounds was also compared in this RPLC mode.

Preparation of LaB{sub 3}O{sub 6}:Eu{sup 3+} phosphors by a facile precursor method and their luminescent properties

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

Wang, Xia; Liang, Pan; Huang, Hong-Sheng

2014-04-01

Graphical abstract: LaB{sub 3}O{sub 6}:Eu{sup 3+} phosphor was obtained by calcining the precursor which was synthesized by boric acid melting method. It (a) exhibits much stronger PL intensity than that (b) prepared by conventional solid state reaction method. - Highlights: • A calcining precursor method was used for preparation of LaB{sub 3}O{sub 6}:Eu{sup 3+} phosphor. • Precursor was prepared by boric acid melting method. • The luminescence intensity of LaB{sub 3}O{sub 6}:Eu{sup 3+} was enhanced by the present method. - Abstract: The LaB{sub 3}O{sub 6}:Eu{sup 3+} phosphors were prepared by calcining the precursors which were synthesized by boric acid meltingmore » method using rare earth oxide and boric acid as raw materials, and they were characterized by EDS, XRD, IR, SEM and PL. The influences of reaction temperature for the preparation of precursor and subsequent calcination temperature and time of precursor on the luminescence properties of LaB{sub 3}O{sub 6}:Eu{sup 3+} phosphor were investigated. The results showed that the LaB{sub 3}O{sub 6}:Eu{sup 3+} phosphors with maximum luminescent intensity were obtained by calcining precursor at 1000 °C for 6 h, in which the precursor was prepared at 200 °C for 72 h. Compared with the conventional high temperature solid-state reaction method, the pure LaB{sub 3}O{sub 6}:Eu{sup 3+} phosphor can be obtained at relatively lower calcination temperature by the precursor method and exhibits much stronger emission intensity.« less

Determination of hydrolyzable tannins in the fruit of Terminalia chebula Retz. by high-performance liquid chromatography and capillary electrophoresis.

PubMed

Juang, Lih-Jeng; Sheu, Shuenn-Jyi; Lin, Ta-Chen

2004-06-01

A RP-HPLC method for determining fourteen components (gallic acid, chebulic acid, 1,6-di-O-galloyl-D-glucose, punicalagin, 3,4,6-tri-O-galloyl-D-glucose, casuarinin, chebulanin, corilagin, neochebulinic acid, terchebulin, ellagic acid, chebulagic acid, chebulinic acid, and 1,2,3,4,6-penta-O-galloyl-D-glucose) in the fruit of Terminalia chebula Retz. is described. The separation was achieved within 80 min using a binary gradient with mobile phases consisting of a pH 2.7 phosphoric acid solution and an 80% CH3CN solution. Capillary electrophoretic analyses were also attempted, and it was found that CZE (25 mM Na2B4O7, 5 mM NaH2PO4, pH 7.0) was an efficient method for the separation of gallotannins, while an MEKC method (25 mM Na2B4O7, 5 mM NaH2PO4, 20 mM SDS, pH 7.0, and 10% acetonitrile) provided a better separation for most of the tannins examined. The HPLC and CE methods developed were both successfully applied to the assay of tannins in commercial samples of Chebulae Fructus.

Stress Corrosion Evaluation of Various Metallic Materials for the International Space Station Water Recycling System

NASA Technical Reports Server (NTRS)

Torres, P. D.

2015-01-01

A stress corrosion evaluation was performed on Inconel 625, Hastelloy C276, titanium commercially pure (TiCP), Ti-6Al-4V, Ti-6Al-4V extra low interstitial, and Cronidur 30 steel as a consequence of a change in formulation of the pretreatment for processing the urine in the International Space Station Environmental Control and Life Support System Urine Processing Assembly from a sulfuric acid-based to a phosphoric acid-based solution. The first five listed were found resistant to stress corrosion in the pretreatment and brine. However, some of the Cronidur 30 specimens experienced reduction in load-carrying ability.

High-pressure nuclear magnetic resonance studies of fuel cell membranes

NASA Astrophysics Data System (ADS)

Mananga, Eugene Stephane

This thesis focuses on the use of high pressure NMR to study transport properties in electrolyte membranes used for fuel cells. The main concern is in studying the self-diffusion coefficients of ions and molecules in membranes and solutions, which can be used to characterize electrolytes in fuel cells. For this purpose, a high-pressure fringe field NMR method to study transport properties in material systems useful for fuel cell and battery electrolytes, was designed, developed, and implemented. In this investigation, pressure is the thermodynamic variable to obtain additional information about the ionic transport process, which could yield the crucial parameter, activation volume. Most of the work involves proton NMR, with additional investigations of others nuclei, such as fluorine, phosphorus and lithium. Using the FFG method, two fuel cell membrane types (NAFION-117, SPTES), and different dilutions of phosphoric acid were investigated, as was LiTf salt in Diglyme solution, which is used as a lithium battery electrolyte. In addition to high-pressure NMR diffusion measurements carried out in the fringe field gradient for the investigation of SPTES, pulse field gradient spin echo NMR was also used to characterize the water diffusion, in addition to measuring diffusion rates as a function of temperature. This second method allows us to measure distinct diffusion coefficients in cases where the different nuclear (proton) environments can be resolved in the NMR spectrum. Polymer electrolyte systems, in which the mobility of both cations and anions is probed by NMR self-diffusion measurements using standard pulsed field gradient methods and static gradient measurements as a function of applied hydrostatic pressure, were also investigated. The material investigated is the low molecular weight liquid diglyme/LiCF3SO3 (LiTf) complexes which can be used as electrolytes in lithium batteries. Finally, high-pressure diffusion coefficient measurements of phosphoric acid in water at different concentrations: proton (1H) and phosphorus (31P) nuclei have been performed using the static field gradient spin-echo nuclear magnetic resonance. This study is expected to be helpful in improving the understanding of phosphoric acid fuel cell technology.

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).

Spectral properties of Dy3+ doped ZnAl2O4 phosphor

NASA Astrophysics Data System (ADS)

Prakash, Ram; Kumar, Sandeep; Mahajan, Rubby; Khajuria, Pooja; Kumar, Vinay; Choudhary, R. J.; Phase, D. M.

2018-05-01

Herein, Dy3+ doped ZnAl2O4 phosphor was synthesized by the solution combustion method. The synthesized phosphor was characterized by X-ray diffraction (XRD), photoluminescence (PL) spectroscopy, UV-Vis spectroscopy and X-ray photoelectron spectroscopy (XPS). The phase purity of the phosphor was confirmed by the XRD studies that showed cubic symmetry of the synthesized phosphor. Under UV excitation (388 nm) the PL emission spectrum of the phosphor shows characteristic transition from the Dy3+ ion. A band gap of 5.2 eV was estimated from the diffused reflectance spectroscopy. The surface properties of the phosphor were studied using the X-ray photoelectron spectroscopy.

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

Code of Federal Regulations, 2012 CFR

2012-04-01

... 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 an... conditions of time and temperature characterizing the conditions of its intended use, as determined from...

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

Code of Federal Regulations, 2013 CFR

2013-04-01

... 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 an... conditions of time and temperature characterizing the conditions of its intended use, as determined from...

Interfacial characteristics of an epoxy composite reinforced with phosphoric acid-functionalized Kevlar fibers

NASA Astrophysics Data System (ADS)

Li, J.; Xia, Y. C.

2010-07-01

A Kevlar fiber was functionalized with the phosphoric acid (PA) of different concentrations. The surface characteristics of the fiber were examined by using the X-ray photoelectron spectroscopy. It was found that the PA functionalization considerably increased the bond strength between the Kevlar fiber and an epoxy matrix.

46 CFR 153.558 - Special requirements for phosphoric acid.

Code of Federal Regulations, 2010 CFR

2010-10-01

... CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and... containment system must be: (a) Lined with natural rubber or neoprene; (b) Lined with a material approved for phosphoric acid tanks by the Commandant (CG-522); or (c) Made of a stainless steel that resists corrosion by...

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

USDA-ARS?s Scientific Manuscript database

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...

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.

Studies on the in vitro and in vivo antifungal activity of fosetyl-al and phosphorous acid

Treesearch

Mark A. Fenn; M.D. Coffey

1984-01-01

In a low-phosphate medium fosetyl-Al showed a much higher activity in vitro against Phytophthora than previously reported in the literature. Both fosetyl-Al, and more particularly phosphorous acid (H3PO3), were highly inhibitory in vitro against several species of Phytophthora....

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.

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. Copyright © 2015 Elsevier Ltd. All rights reserved.

HOMOGENEOUS NUCLEAR POWER REACTOR

DOEpatents

King, L.D.P.

1959-09-01

A homogeneous nuclear power reactor utilizing forced circulation of the liquid fuel is described. The reactor does not require fuel handling outside of the reactor vessel during any normal operation including complete shutdown to room temperature, the reactor being selfregulating under extreme operating conditions and controlled by the thermal expansion of the liquid fuel. The liquid fuel utilized is a uranium, phosphoric acid, and water solution which requires no gus exhaust system or independent gas recombining system, thereby eliminating the handling of radioiytic gas.

Methods for suppressing isomerization of olefin metathesis products

DOEpatents

Firth, Bruce E.; Kirk, Sharon E.; Gavaskar, Vasudeo S.

2015-09-22

A method for suppressing isomerization of an olefin metathesis product produced in a metathesis reaction includes adding an isomerization suppression agent to a mixture that includes the olefin metathesis product and residual metathesis catalyst from the metathesis reaction under conditions that are sufficient to passivate at least a portion of the residual metathesis catalyst. The isomerization suppression agent is phosphorous acid, a phosphorous acid ester, phosphinic acid, a phosphinic acid ester or combinations thereof. Methods of refining natural oils are described.

Effect of Reduced Phosphoric Acid Pre-etching Times 
on Enamel Surface Characteristics and Shear Fatigue Strength Using Universal Adhesives.

PubMed

Tsujimoto, Akimasa; Fischer, Nicholas; Barkmeier, Wayne; Baruth, Andrew; Takamizawa, Toshiki; Latta, Mark; Miyazaki, Masashi

2017-01-01

To examine the effect of reduced phosphoric acid pre-etching times on enamel fatigue bond strength of universal adhesives and surface characteristics by using atomic force microscopy (AFM). Three universal adhesives were used in this study (Clearfil Universal Bond [C], G-Premio Bond [GP], Scotchbond Universal Adhesive [SU]). Four pre-etching groups were employed: enamel pre-etched with phosphoric acid and immediately rinsed with an air-water spray, and enamel pre-etched with phosphoric acid for 5, 10, or 15 s. Ground enamel was used as the control group. For the initial bond strength test, 15 specimens per etching group for each adhesive were used. For the shear fatigue test, 20 specimens per etching group for each adhesive were loaded using a sine wave at a frequency of 20 Hz for 50,000 cycles or until failure occurred. Initial shear bond strengths and fatigue shear strengths of composite adhesively bonded to ground and pre-etched enamel were determined. AFM observations of ground and pre-etched enamel were also conducted, and surface roughness as well as surface area were evaluated. The initial shear bond strengths and fatigue shear strengths of the universal adhesives in the pre-etched groups were significantly higher than those of the control group, and were not influenced by the pre-etching time. Significantly higher surface roughness and surface area of enamel surfaces in pre-etched groups were observed compared with those in the control group. While the surface area was not significantly influenced by etching time, surface roughness of the enamel surfaces in the pre-etched groups significantly increased with pre-etching time. The results of this in vitro study suggest that reduced phosphoric acid pre-etching times do not impair the fatigue bond strength of universal adhesives. Although fatigue bond strength and surface area were not influenced by phosphoric-acid etching times, surface roughness increased with increasing etching time.

Impact of pH and application time of meta-phosphoric acid on resin-enamel and resin-dentin bonding.

PubMed

Cardenas, A F M; Siqueira, F S F; Bandeca, M C; Costa, S O; Lemos, M V S; Feitora, V P; Reis, A; Loguercio, A D; Gomes, J C

2018-02-01

To evaluate the immediate microshear resin-enamel bond strength (μSBS) and the immediate and 6-month microtensile bond strength (μTBS) and nanoleakage (NL) of the adhesive interface performed by different pHs of 40% meta-phosphoric acid (MPA) were compared with conventional 37% ortho-phosphoric acid (OPA) under different application times. Additionally, the enamel etching patterns were evaluated and the chemical/morphological changes induced by these differents groups were evaluated. One hundred and ninety-eight extracted human molars were randomly assigned into experimental groups according to the combination of independent variables: Acid [37% ortho-phosphoric acid (OPA), 40% meta-phosphoric acid (MPA) at pHs of: 0.5, 1 and 2] and Application Time [7, 15 and 30s]. Enamel-bond specimens were prepared and tested under μSBS. Resin-dentin beams were tested under μTBS tested immediately or after 6-months of water storage. Nanoleakage was evaluated using bonded-beams of each tooth/time-period. Enamel etching pattern and chemical and ultra-morphology analyses were also performed. The μSBS (MPa) data were subjected to a two-way repeated measures ANOVA (Acid vs. Application time). For μTBS, Acid vs application time vs storage time data were subjected to three-way ANOVA and Tukey's test (α = 0.05). MPA pH 0.5 showed μTBS similar to OPA, independently of the application time on enamel (p>0.05) or dentin (p>0.05). OPA provided higher nanoleakage values than MPA (p = 0.003). Significant decreases in TBS and increases in NL were only observed for OPA after 6 months (p = 0.001). An increase in the application time resulted in a more pronounced etching pattern for MPA. Chemical analysis showed that dentin demineralized by MPA depicted peaks of brushite and octacalcium phosphate. MPA exposed less collagen than OPA. However, optimal results for MPA were dependent on pH/application time. The use of 40% meta-phosphoric acid with a pH of 0.5 is an alternative acid-etching agent for dentin and enamel bonding. Furthermore, the use of MPA preserves the resin-dentin interface over a 6-months period, due to presence of brushite and octacalcium phosphate and a reduced demineralization pattern. Copyright © 2017 Elsevier Ltd. All rights reserved.

New Insight into Phase Formation of MxMg2Al4+xSi5−xO18:Eu2+ Solid Solution Phosphors and Its Luminescence Properties

PubMed Central

Zhou, Jun; Xia, Zhiguo; Chen, Mingyue; Molokeev, Maxim S.; Liu, Quanlin

2015-01-01

Here we reported the phase formation of MxMg2Al4+xSi5−xO18:Eu2+ (M = K, Rb) solid solution phosphors, where M+ ions were introduced into the void channels of Mg2Al4Si5O18 via Al3+/Si4+ substitution to keep the charge balance. XRD results revealed that the as-prepared phosphors with different M+ contents were iso-structural with Mg2Al4Si5O18 phase. The combined analysis of the Rietveld refinement and high resolution transmission electron microscopy (HRTEM) results proved that M+ ions were surely introduced into the intrinsic channels in Mg2Al4Si5O18. The emission peaks of MxMg2Al4+xSi5−xO18:Eu2+ (M = K, Rb) phosphors with various x values performed a systematic red-shift tendency, which was ascribed to the elongation of [MgO6] octahedra. The temperature stable photoluminescence and internal quantum efficiency (QE) of MxMg2Al4+xSi5−xO18:Eu2+ (M = K, Rb) phosphors were enhanced owing to the filling of M+ in the void channels suggesting a new insight to design the solid solution phosphors with improved photoluminescence properties. PMID:26190348

One-step hydrothermal synthesis of carboxyl-functionalized upconversion phosphors for bioapplications.

PubMed

Yang, Jianping; Shen, Dengke; Li, Xiaomin; Li, Wei; Fang, Yin; Wei, Yong; Yao, Chi; Tu, Bo; Zhang, Fan; Zhao, Dongyuan

2012-10-22

In this paper, we report a facile one-step hydrothermal method to synthesize phase-, size-, and shape-controlled carboxyl-functionalized rare-earth fluorescence upconversion phosphors by using a small-molecule binary acid, such as malonic acid, oxalic acid, succinic acid, or tartaric acid as capping agent. The crystals, from nano- to microstructures with diverse shapes that include nanospheres, microrods, hexagonal prisms, microtubes, microdisks, polygonal columns, and hexagonal tablets, can be obtained with different reaction times, reaction temperatures, molar ratios of capping agent to sodium hydroxide, and by varying the binary acids. Fourier transform infrared, thermogravimetric analysis, and upconversion luminescence spectra measurements indicate that the synthesized NaYF(4):Yb/Er products with hydrophilic carboxyl-functionalized surface offer efficient upconversion luminescent performance. Furthermore, the antibody/secondary antibody conjugation can be realized by the carboxyl-functionalized surfaces of the upconversion phosphors, thus indicating the potential bioapplications of these kinds of materials. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Self-Assembled Soft Optical Negative Index Materials

DTIC Science & Technology

2008-08-05

within the MURI indicated that anodization of aluminum films provides hexagonal nano-hole arrays, which, when backfilled with e.g. silver via...bath determine pore size and spacing. Then AAO is removed with chromic and phosphoric acid at 70°C for 6 hrs. A 2nd anodization results in hexagonal...array of pores. Anodization time sets membrane thickness. Pores widened in acid such as phosphoric acid. The barrier layer is thinned by gradually

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...

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.

A Technique for the Microstructural Examination of Polycrystalline Graphites

DTIC Science & Technology

1959-02-01

dichromate in concentrated phosphoric acid . This etchsnt reacted quite readily with the graphite surface, yet at a rate that was...formation of lamellar compounds, and carbide formation at high temperatues . Of the three classes of reaction, oxidation seems to...reagents and conditions were directed toward preliminary studies of such chemical oxidants as potassium dichromate-phosphoric acid mixtures

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.

Use of super acids to digest chrysotile and amosite asbestos in simple mixtures or matrices found in building materials compositions

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

Sugama, T.; Petrakis, L.; Webster, R.P.

A composition for converting asbestos-containing material to environmentally benign components is provided. The composition comprises a fluoro acid decomposing agent which can be applied to either amosite-containing thermal insulation or chrysotile-containing fire-proof material or to any asbestos-containing material which includes of chrysotile and amosite asbestos. The fluoro acid decomposing agent includes FP{sub 0}(OH){sub 2}, hexafluorophosphoric acid, a mixture of hydrofluoric and phosphoric acid and a mixture of hexafluorophosphoric acid and phosphoric acid. A method for converting asbestos-containing material to environmentally benign components is also provided.

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.

Oxidation of white phosphorus by peroxides in water

NASA Astrophysics Data System (ADS)

Abdreimova, R. R.; Akbaeva, D. N.; Polimbetova, G. S.

2017-10-01

A mixture of hypophosphorous, phosphorous, and phosphoric acids is formed during the anaerobic oxidation of white phosphorus by peroxides [ROOH; R = H, 3-ClC6H4CO, (CH3)3C] in water. The rate of reactions grows considerably upon adding nonpolar organic solvents. The activity series of peroxides and solvents are determined experimentally. NMR spectroscopy shows that the main product of the reaction is phosphorous acid, regardless of the nature of the peroxide and solvent. A radical mechanism of oxidation of white phosphorus by peroxides in water is proposed. It is initiated by the homolysis of peroxide with the formation of HO• radicals that are responsible for the homolytic opening of phosphoric tetrahedrons. Further oxidation and stages of the hydrolysis of intermediate phosphorus-containing compounds yield products of the reaction.

A new, bright and hard aluminum surface produced by anodization

NASA Astrophysics Data System (ADS)

Hou, Fengyan; Hu, Bo; Tay, See Leng; Wang, Yuxin; Xiong, Chao; Gao, Wei

2017-07-01

Anodized aluminum (Al) and Al alloys have a wide range of applications. However, certain anodized finishings have relatively low hardness, dull appearance and/or poor corrosion resistance, which limited their applications. In this research, Al was first electropolished in a phosphoric acid-based solution, then anodized in a sulfuric acid-based solution under controlled processing parameters. The anodized specimen was then sealed by two-step sealing method. A systematic study including microstructure, surface morphology, hardness and corrosion resistance of these anodized films has been conducted. Results show that the hardness of this new anodized film was increased by a factor of 10 compared with the pure Al metal. Salt spray corrosion testing also demonstrated the greatly improved corrosion resistance. Unlike the traditional hard anodized Al which presents a dull-colored surface, this newly developed anodized Al alloy possesses a very bright and shiny surface with good hardness and corrosion resistance.

Lipophilic ternary complexes in liquid-liquid extraction of trivalent lanthanides

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

Lumetta, Gregg J.; Levitskaia, Tatiana G.; Latesky, Stanley

2012-03-01

The formation of ternary complexes between lanthanide ions [Nd(III) or Eu(III)], octyl(phenyl)-N,N-diisobutyl-carbamoylmethylphosphine oxide (CMPO), and bis-(2-ethylhexyl)phosphoric acid (HDEHP) was probed by liquid-liquid extraction and spectroscopic techniques. Equilibrium modeling of data for the extraction of Nd(III) or Eu(III) from lactic acid media into n-dodecane solutions of CMPO and HDEHP indicates the predominant extracted species are of the type [Ln(AHA){sub 2}(A)] and [Ln(CMPO)(AHA){sub 2}(A)], where Ln = Nd or Eu and A represents the DEHP{sup -} anion. FTIR (for both Eu and Nd) and visible spectrophotometry (in the case of Nd) indicate the formation of the [Ln(CMPO)(A){sup 3}] complexes when CMPO ismore » added to n-dodecane solutions of the LnA{sub 3} compounds. Both techniques indicate a stronger propensity of CMPO to complex Nd(III) versus Eu(III).« less

Evaluation of different types of enamel conditioning before application of a fissure sealant.

PubMed

Ciucchi, Philip; Neuhaus, Klaus W; Emerich, Marta; Peutzfeldt, Anne; Lussi, Adrian

2015-01-01

The aim of the study was to compare fissure sealant quality after mechanical conditioning of erbium-doped yttrium aluminium garnet (Er:YAG) laser or air abrasion prior to chemical conditioning of phosphoric acid etching or of a self-etch adhesive. Twenty-five permanent molars were initially divided into three groups: control group (n = 5), phosphoric acid etching; test group 1 (n = 10), air abrasion; and test group 2, (n = 10) Er:YAG laser. After mechanical conditioning, the test group teeth were sectioned buccolingually and the occlusal surface of one half tooth (equal to one sample) was acid etched, while a self-etch adhesive was applied on the other half. The fissure system of each sample was sealed, thermo-cycled and immersed in 5% methylene dye for 24 h. Each sample was sectioned buccolingually, and one slice was analysed microscopically. Using specialized software microleakage, unfilled margin, sealant failure and unfilled area proportions were calculated. A nonparametric ANOVA model was applied to compare the Er:YAG treatment with that of air abrasion and the self-etch adhesive with phosphoric acid (α = 0.05). Test groups were compared to the control group using Wilcoxon rank sum tests (α = 0.05). The control group displayed significantly lower microleakage but higher unfilled area proportions than the Er:YAG laser + self-etch adhesive group and displayed significantly higher unfilled margin and unfilled area proportions than the air-abrasion + self-etch adhesive group. There was no statistically significant difference in the quality of sealants applied in fissures treated with either Er:YAG laser or air abrasion prior to phosphoric acid etching, nor in the quality of sealants applied in fissures treated with either self-etch adhesive or phosphoric acid following Er:YAG or air-abrasion treatment.

Effect of post-space treatment on retention of fiber posts in different root regions using two self-etching systems.

PubMed

Zhang, Ling; Huang, Li; Xiong, Yu; Fang, Ming; Chen, Ji-Hua; Ferrari, Marco

2008-06-01

The effect of post-space treatment on the retention of fiber posts in different root regions was evaluated using two self-etching systems. Post spaces were prepared in extracted premolars and then the root canals were subjected to one of the following post-space treatments: (i) water irrigation (control); (ii) etching with 35% phosphoric acid for 30 s; (iii) irrigation with 17% EDTA followed by 5.25% sodium hypochlorite (NaOCl); and (iv) ultrasonic agitation associated with 17% EDTA and 5.25% NaOCl irrigating solutions. The dentin surfaces were examined under scanning electron microscopy (SEM) after different post-space treatments. Fiber posts were then luted in the treated roots using resin cement with either Clearfil SE Bond or Clearfil DC Bond, and the thin-slice push-out test was performed. Scanning electron microscopy showed that all the post-space treatments tested were effective in removal of the smear layer of debris, or sealer/gutta-percha remnants, on the root canal. The apical push-out strength was affected by post-space treatment. Both 35% phosphoric acid etching and ultrasonic agitation in combination with EDTA/NaOCl irrigation improved the apical push-out strength of the fiber post, regardless of the type of self-etching system. A solo irrigation with an EDTA/NaOCl solution resulted in a lower apical push-out strength compared with the other two experimental groups.

Surface modification of CoCr alloy using varying concentrations of phosphoric and phosphonoacetic acids: albumin and fibrinogen adsorption, platelet adhesion, activation, and aggregation studies.

PubMed

Thiruppathi, Eagappanath; Larson, Mark K; Mani, Gopinath

2015-01-01

CoCr alloy is commonly used in various cardiovascular medical devices for its excellent physical and mechanical properties. However, the formation of blood clots on the alloy surfaces is a serious concern. This research is focused on the surface modification of CoCr alloy using varying concentrations (1, 25, 50, 75, and 100 mM) of phosphoric acid (PA) and phosphonoacetic acid (PAA) to generate various surfaces with different wettability, chemistry, and roughness. Then, the adsorption of blood plasma proteins such as albumin and fibrinogen and the adhesion, activation, and aggregation of platelets with the various surfaces generated were investigated. Contact angle analysis showed PA and PAA coatings on CoCr provided a gradient of hydrophilic surfaces. FTIR showed PA and PAA were covalently bound to CoCr surface and formed different bonding configurations depending on the concentrations of coating solutions used. AFM showed the formation of homogeneous PA and PAA coatings on CoCr. The single and dual protein adsorption studies showed that the amount of albumin and fibrinogen adsorbed on the alloy surfaces strongly depend on the type of PA and PAA coatings prepared by different concentrations of coating solutions. All PA coated CoCr showed reduced platelet adhesion and activation when compared to control CoCr. Also, 75 and 100 mM PA-CoCr showed reduced platelet aggregation. For PAA coated CoCr, no significant difference in platelet adhesion and activation was observed between PAA coated CoCr and control CoCr. Thus, this study demonstrated that CoCr can be surface modified using PA for potentially reducing the formation of blood clots and improving the blood compatibility of the alloy.

Effect of silicate and phosphate additives on the kinetics of the oxygen evolution reaction in valve-regulated lead/acid batteries

NASA Astrophysics Data System (ADS)

Vinod, M. P.; Vijayamohanan, K.; Joshi, S. N.

Effect of sodium silicate and phosphoric acid additives on the kinetics of oxygen evolution on PbO 2 electrodes in sulfuric acid has been studied in gelled and flooded electrolytes with relevance to valve-regulated lead/acid batteries. A comparison of the open-circuit potential versus time transients, with and without these additives, indicates that the additives suppress self-discharge of the electrodes. Tafel polarization studies also suggest that the addition of phosphoric acid attenuates the rate of oxygen evolution reaction. These findings have been supported with cyclic voltammetric data.

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

SEPARATION OF Cs$sup 137$ FROM HIGH-ACTIVITY RADIOACTIVE WASTE (in Dutch)

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

None

1963-01-01

A process was developed on a laboratory scale to separate Cs/sup 137/ from waste fuels of atomic reactors. The recovery of this powerful and industrially important gamma emitter of 30 years half life is said to be so simple as to make it possible on an industrial scale. It is based on the preferential absorption of Cs by ammonium phosphor-molybdate from the nitric acid solution of the waste material and the subsequent extraction of Cs from its absorber. This method is more practical than other processes which are based upon precipitation and recrystallization of cesium salts. It was successfully testedmore » on waste solutions of very different compositions. (OID)« less

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. © 2016 Eur J Oral Sci.

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.

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.

Use Of Superacids To Digest Chrysotile And Amosite Asbestos In Simple Mixtures Or Matrices Found In Building Materials Compositions

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

Sugama, Toshifumi; Petrakis, Leon; Webster, Ronald P.

A composition for converting asbestos-containing material to environmentally benign components is provided. The composition comprises a flouro acid decomposing agent which can be applied to either amosite-containing thermal insulation or chrysotile-containing fire-proof material or to any asbestos-containing material which includes of chrysotile and amosite asbestos. The fluoro acid decomposing agent includes FP(O)(OH).sub.2, hexafluorophosphoric acid, a mixture of hydrofluoric and phosphoric acid and a mixture of hexafluorophosphoric acid and phosphoric acid. A method for converting asbestos-containing material to environmentally benign components is also provided

Improvement of the performance of the positive electrode in the lead/acid battery by addition of boric acid

NASA Astrophysics Data System (ADS)

Badawy, W. A.; El-Egamy, S. S.

A major disadvantage of the lead/acid battery is the decrease in voltage during operation which makes it unsuitable for systems sensitive to voltage fluctuations. Additives like BaSO 4 or SrSO 4, which are isomorphous to PbSO 4, have been used to overcome this problem. Phosphoric acid and the various phosphates have long been used to improve the performance of the positive electrode of the battery. A beneficial effect of phosphoric acid is to inhibit the rate of the self-discharge reaction of the positive electrode in the lead/acid battery. However, adverse effects of phosphoric acid include capacity loss in the initial cycles, excessive mossing, especially at high H 3PO 4 concentrations, and poor low-temperature performance (decrease in the rate of PbSO 4 oxidation). The effect of boric acid as an additive substituting for H 3PO 4 has been investigated using linear sweep voltammetry, constant potential and impedance measurements. The results show that boric acid markedly improves the kinetics of the {PbO 2}/{PbSO 4} couple and removes the problems encountered during the usage of H 3PO 4.

Speciation of antimony in airborne particulate matter using ultrasound probe fast extraction and analysis by HPLC-HG-AFS.

PubMed

Bellido-Martín, A; Gómez-Ariza, J L; Smichowsky, P; Sánchez-Rodas, D

2009-09-07

A fast extraction procedure has been developed for Sb(III) and Sb(V) oxoanions speciation in airborne particulate matter samples. Different extraction media (diammonium tartrate, hidroxilammonium clorhidrate, citric acid+ascorbic acid, phosphoric acid and citrate solutions) were tried, with assistance of an ultrasonic probe. The operation power and time of extraction were also optimized. The higher extraction recoveries were obtained with a 100 mmol L(-1) hidroxilammonium clorhidrate aqueous solution assisted by the ultrasound probe operated at 50 W during 3 min. The extracts were analyzed by HPLC-HG-AFS. The chromatographic separation of Sb(III) and Sb(V) was also optimized using diammonium tartrate and phthalic acid as mobile phases. The separation of both Sb species was performed in less than 3 min under isocratic conditions, using a 200 mmol L(-1) diammonium tartrate solution. The proposed extraction procedure and the HPLC-HG-AFS instrumental coupling have been successfully applied to airborne particulate matter samples, with high Sb content, collected in heavy traffic streets from Buenos Aires (Argentina). The results showed the presence of both Sb species at similar concentrations in the ng m(-3) level. The extraction yield was higher than 90% for all the analyzed samples.

The determination of calcium in phosphate, carbonate, and silicate rocks by flame photometer

USGS Publications Warehouse

Kramer, Henry

1956-01-01

A method has been developed for the determination of calcium in phosphate, carbonate, and silicate rocks using the Beckman flame photometer, with photomultiplier attachement. The sample is dissolved in hydrofluoric, nitric, and perchloric acids, the hydrofluoric and nitric acids are expelled, a radiation buffer consisting of aluminum, magnesium, iron, sodium, potassium, phosphoric acid, and nitric acid is added, and the solution is atomized in an oxy-hydrogen flame with an instrument setting of 554 mµ. Measurements are made by comparison against calcium standards, prepared in the same manner, in the 0 to 50 ppm range. The suppression of calcium emission by aluminum and phosphate was overcome by the addition of a large excess of magnesium. This addition almost completely restores the standard curve obtained from a solution of calcium nitrate. Interference was noted when the iron concentration in the aspirated solution (including the iron from the buffer) exceeded 100 ppm iron. Other common rock-forming elements did not interfere. The results obtained by this procedure are within ± 2 percent of the calcium oxide values obtained by other methods in the range 1 to 95 percent calcium oxide. In the 0 to 1 percent calcium oxide range the method compares favorably with standard methods.

Growth of SiO 2 on InP substrate by liquid phase deposition

NASA Astrophysics Data System (ADS)

Lei, Po Hsun; Yang, Chyi Da

2010-04-01

We have grown silicon dioxide (SiO 2) on indium phosphorous (InP) substrate by liquid phase deposition (LPD) method. With inserting InP wafer in the treatment solution composed of SiO 2 saturated hydrofluorosilicic acid (H 2SiF 6), 0.1 M boric acid (H 3BO 3) and 1.74 M diluted hydrochloric acid (HCl), the maximum deposition rate and refractive index for the as-grown LPD-SiO 2 film were about 187.5 Å/h and 1.495 under the constant growth temperature of 40 °C. The secondary ion mass spectroscope (SIMS) and energy dispersive X-ray (EDX) confirmed that the elements of silicon, oxygen, and chloride were found in the as-grown LPD-SiO 2 film. On the other hand, the effects of treatment solution incorporated with the hydrogen peroxide (H 2O 2) that can regulate the concentration of OH - ion were also shown in this article. The experimental results represented that the deposition rate decreases with increasing the concentration of hydrogen peroxide due to the reduced concentration of SiO 2 saturated H 2SiF 6 in treatment solution.

A facile method to prepare "green" nano-phosphors with a large Stokes-shift and solid-state enhanced photophysical properties based on surface-modified gold nanoclusters.

PubMed

Cheng, C H; Huang, H Y; Talite, M J; Chou, W C; Yeh, J M; Yuan, C T

2017-12-15

Colloidal nano-materials, such as quantum dots (QDs) have been applied to light-conversion nano-phosphors due to their unique tunable emission. However, most of the QDs involve toxic elements and are synthesized in a hazardous solvent. In addition, conventional QD nano-phosphors with a small Stokes shift suffered from reabsorption losses and aggregation-induced quenching in the solid state. Here, we demonstrate a facile, matrix-free method to prepare eco-friendly nano-phosphors with a large Stokes shift based on aqueous thiolate-stabilized gold nanoclusters (GSH-AuNCs) with simple surface modifications. Our method is just to drop GSH-AuNCs solution on the aluminum foil and then surface-modified AuNCs (Al-GSH-AuNCs) can be spontaneously precipitated out of the aqueous solution. Compared with pristine GSH-AuNCs in solution, the Al-GSH-AuNCs exhibit enhanced solid-state PL quantum yields, lengthened PL lifetime, and spectral blue shift, which can be attributed to the aggregation-induced emission enhancement facilitated by surface modifications. Such surface-treatment induced aggregation of AuNCs can restrict the surface-ligand motion, leading to the enhancement of PL properties in the solid state. In addition, the Al-GSH-AuNCs nano-phosphors with a large Stokes shift can mitigate the aggregation-induced PL quenching and reabsorption losses, which would be potential candidates for "green" nano-phosphors. Copyright © 2017 Elsevier Inc. All rights reserved.

High power density fuel cell comprising an array of microchannels

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

Sopchak, David A; Morse, Jeffrey D; Upadhye, Ravindra S

2014-05-06

A phosphoric acid fuel cell according to one embodiment includes an array of microchannels defined by a porous electrolyte support structure extending between bottom and upper support layers, the microchannels including fuel and oxidant microchannels; fuel electrodes formed along some of the microchannels; and air electrodes formed along other of the microchannels. A method of making a phosphoric acid fuel cell according to one embodiment includes etching an array of microchannels in a substrate, thereby forming walls between the microchannels; processing the walls to make the walls porous, thereby forming a porous electrolyte support structure; forming anode electrodes along somemore » of the walls; forming cathode electrodes along other of the walls; and filling the porous electrolyte support structure with a phosphoric acid electrolyte. Additional embodiments are also disclosed.« less

Acid-switched Eu(III) coordination inside reverse aggregates: Insights into a synergistic liquid-liquid extraction system

DOE PAGES

Ellis, Ross J.

2016-08-09

Determining the structure of complex solutions bearing metal ions is challenging, but crucial for developing important technologies such as liquid-liquid extraction for metal refining and separation purposes. Herein, the structure of an organic Eu(III) solution consisting a binary mixture of lipophilic ligands di-2-ethylhexyl phosphoric acid (HDEHP) and tetraoctyl diglycolamide (TODGA) in dodecane is studied using synchrotron small angle X-ray scattering (SAXS) and X-ray absorption fine structure spectroscopy (EXAFS). This system is of technological importance in f-element separation for nuclear fuel cycle applications, where extraction is controlled by varying nitric acid concentration. Extraction is promoted at low and high concentration, butmore » is retarded at intermediate concentration, leading to a U-shaped function; the structural origins of which we investigate. At the nanoscale, the solution is apparently comprised of reverse micelles with polar cores of approximately 1 nm in size, and these remain virtually unchanged as acid concentration is varied. Inside the polar cores, the coordination environment of Eu(III) switches from a 9-coordinate [Eu(TODGA) 3] 3+ motif at high acid, to a 6-coordinate HDEHP-dominated complex resembling Eu(HDEHP·DEHP) 3 at low acid. The results show that extraction is controlled within the coordination sphere, where it is promoted under conditions that favor coordination of either one of the two organic ligands, but is retarded under conditions that encourage mixed complexes. Lastly, our results link solution structure with ion transport properties in a technologically-important liquid-liquid ion extraction system.« less

In situ modification of activated carbons developed from a native invasive wood on removal of trace toxic metals from wastewater.

PubMed

de Celis, J; Amadeo, N E; Cukierman, A L

2009-01-15

Activated carbons were developed by phosphoric acid activation of sawdust from Prosopis ruscifolia wood, an indigenous invasive species of degraded lands, at moderate conditions (acid/precursor ratio=2, 450 degrees C, 0.5h). For in situ modification of their characteristics, either a self-generated atmosphere or flowing air was used. The activated carbons developed in the self-generated atmosphere showed higher BET surface area (2281m2/g) and total pore volume (1.7cm3/g) than those obtained under flowing air (1638m2/g and 1.3cm3/g). Conversely, the latter possessed a higher total amount of surface acidic/polar oxygen groups (2.2meq/g) than the former (1.5meq/g). To evaluate their metal sorption capability, adsorption isotherms of Cu(II) ion from model solutions were determined and properly described by the Langmuir model. Maximum sorption capacity (Xm) for the air-derived carbons (Xm=0.44mmol/g) almost duplicated the value for those obtained in the self-generated atmosphere (Xm=0.24mmol/g), pointing to a predominant effect of the surface functionalities on metal sequestering behaviour. The air-derived carbons also demonstrated a superior effectiveness in removing Cd(II) ions as determined from additional assays in equilibrium conditions. Accordingly, effective phosphoric acid-activated carbons from Prosopis wood for toxic metals removal from wastewater may be developed by in situ modification of their characteristics operating under flowing air.

Edge-Functionalization of Pyrene as a Miniature Graphene via Friedel–Crafts Acylation Reaction in Poly(Phosphoric Acid)

PubMed Central

2010-01-01

The feasibility of edge-functionalization of graphite was tested via the model reaction between pyrene and 4-(2,4,6-trimethylphenyloxy)benzamide (TMPBA) in poly(phosphoric acid) (PPA)/phosphorous pentoxide (P2O5) medium. The functionalization was confirmed by various characterization techniques. On the basis of the model study, the reaction condition could be extended to the edge-functionalization of graphite with TMPBA. Preliminary results showed that the resultant TMPBA-grafted graphite (graphite-g-TMPBA) was found to be readily dispersible in N-methyl-2-pyrrolidone (NMP) and can be used as a precursor for edge-functionalized graphene (EFG). PMID:21076664

Discovery of novel solid solution Ca3Si3-x O3+x N4-2x : Eu2+ phosphors: structural evolution and photoluminescence tuning.

PubMed

Wang, Baochen; Liu, Yan-Gai; Huang, Zhaohui; Fang, Minghao; Wu, Xiaowen

2017-12-22

Discovery of novel phosphors is one of the main issues for improving the color rendering index (CRI) and correlated color temperature (CCT) of white light-emitting diodes (w-LEDs). This study mainly presents a systematic research on the synthesis, crystal structure variation and photoluminescence tuning of novel (oxy)nitride solid solution Ca 3 Si 3-x O 3+x N 4-2x : Eu 2+ phosphors. XRD refinements show that lattice distortion occurs when x value diverges the optimum one (x = 1). The lattice distortion causes a widening of emission spectrum and an increase of Stokes shift (ΔSS), which leads to a bigger thermal quenching. With decrease of x value, the emission spectrum shows an obvious red-shift from 505.2 to 540.8 nm, which is attributed to the crystal field splitting. The enhanced crystal field splitting also broadens the excitation spectrum, making it possible to serve as the phosphor for near ultraviolet (n-UV) LEDs. A 3-phosphor-conversion w-LED lamp was fabricated with the as-prepared phosphor, which exhibits high CRI (Ra = 85.29) and suitable CCT (4903.35 K). All these results indicate that the Ca 3 Si 3-x O 3+x N 4-2x : Eu 2+ phosphor can serve as the green phosphor for n-UV w-LEDs, with a tunable spectrum by controlling the crystal structure and morphology.

Electrodeposition of Low Stress Nickel Phosphorous Alloys for Precision Component Fabrication

NASA Technical Reports Server (NTRS)

Engelhaupt, Darell; Ramsey, Brian; Speegle, Chet; Whitaker, Ann F. (Technical Monitor)

2001-01-01

Nickel alloys are favored for electroforming precision components. Nickel phosphorous and nickel cobalt phosphorous are studied in this work. A completely new and innovative electrolytic process eliminates the fumes present in electroless processes and is suitable for electroforming nickel phosphorous and nickel cobalt phosphorous alloys to any desirable thickness, using soluble anodes, without stripping of tanks. Solutions show excellent performance for extended throughput. Properties include, cleaner low temperature operation (40 - 45 C), high Faradaic efficiency, low stress, Rockwell C 52 - 54 hardness and as much as 2000 N per square millimeter tensile strength. Performance is compared to nickel and nickel cobalt electroforming.

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.

1986 fuel cell seminar: Program and abstracts

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

None

1986-10-01

Ninety nine brief papers are arranged under the following session headings: gas industry's 40 kw program, solid oxide fuel cell technology, phosphoric acid fuel cell technology, molten carbonate fuel cell technology, phosphoric acid fuel cell systems, power plants technology, fuel cell power plant designs, unconventional fuels, fuel cell application and economic assessments, and plans for commerical development. The papers are processed separately for the data base. (DLC)

Isolation and structural characterization of sugarcane bagasse lignin after dilute phosphoric acid plus steam explosion pretreatment and its effect on cellulose hydrolysis

Treesearch

Jijiao Zeng; Zhaohui Tong; Letian Wang; J.Y. Zhu; Lonnie Ingram

2014-01-01

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...

Commercial fertilizers 1992

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

Berry, J.T.; Montgomery, M.H.

1992-12-01

Fertilizer consumption information in the USA for 1992 submitted by state regulatory officials is presented. This includes total sales or shipments for farm and non-farm use. Liming materials were excluded. Materials used for manufacture or blending of reported fertilizers or for use in other fertilizers are excluded to avoid double-counting. The consumption of multiple-nutrient and single-nutrient fertilizers is listed. Dry bulk, fluid, and bagged classes are given. Typical fertilizers include: anhydrous ammonia, aqua ammonia, nitrogen solutions, urea, ammonium nitrates, ammonium sulfates, phosphoric acid, superphosphates, potassium chlorides, and potassium sulfates.

Microbial contamination in intraoral phosphor storage plates: the dilemma.

PubMed

de Souza, Tricia Murielly Pereira Andrade; de Castro, Ricardo Dias; de Vasconcelos, Laís César; Pontual, Andréa Dos Anjos; de Moraes Ramos Perez, Flávia Maria; Pontual, Maria Luiza Dos Anjos

2017-01-01

The aims of this study were to evaluate microbial contamination in phosphor storage plates in dental radiology services and discuss the possible origin of this contamination. The sample comprised 50 phosphor plates: 14 plates from service A, 30 from service B, and 6 in the control group, consisting of plates never used. Damp sterile swabs were rubbed on the phosphor plates, and then transferred to tests tubes containing sterile saline solution. Serial dilutions were made, and then inoculated in triplicate on Mueller Hinton agar plates and incubated at 37 °C/48 h, before counting the colony-forming units (CFU). The samples were also seeded in brain-heart infusion medium to confirm contamination by turbidity of the culture medium. All solutions, turbid and clean, were seeded in selective and non-selective media. At service A and B, 50 and 73.3 % of the phosphor plates were contaminated, respectively. This contamination was mainly due to bacteria of the genus Staphylococcus. CFU counts ranged from 26.4 to 80.0 CFU/plate. Most of the phosphor plates evaluated shown to be contaminated, mainly by Staphylococcus ssp. Quantitatively, this contamination occurred at low levels, possibly arising from handling of the plates. The use of a second plastic barrier may have diminished contamination by microorganisms from the oral cavity. There is a risk of cross-contamination by phosphor storage plates used in dental radiology services.

Progress in batteries and solar cells - Volume 6

NASA Astrophysics Data System (ADS)

Shimotake, Hiroshi; Voss, Ernst

The present conference encompasses topics in lithium cell development, manganese cell design, lead-acid batteries, fuel cells, nickel-cadmium and other rechargeable batteries, and battery chargers and related power systems. Attention is given to molten carbonate fuel cells, prospects for sodium/sulfur propulsion batteries, ultrathin lithium batteries, solid state batteries, a gelled electrolyte lead-acid battery for deep discharge applications, and phosphoric acid fuel cells. Also discussed are computer-based battery monitors, a novel nickel-iron battery for electric vehicle applications, conductive polymer electrode electrochemical cells, and catalyst- and electrode-related research for phosphoric acid fuel cells.

Improvement of enamel bond strengths for conventional and resin-modified glass ionomers: acid-etching vs. conditioning*

PubMed Central

Zhang, Ling; Tang, Tian; Zhang, Zhen-liang; Liang, Bing; Wang, Xiao-miao; Fu, Bai-ping

2013-01-01

Objective: This study deals with the effect of phosphoric acid etching and conditioning on enamel micro-tensile bond strengths (μTBSs) of conventional and resin-modified glass ionomer cements (GICs/RMGICs). Methods: Forty-eight bovine incisors were prepared into rectangular blocks. Highly-polished labial enamel surfaces were either acid-etched, conditioned with liquids of cements, or not further treated (control). Subsequently, two matching pre-treated enamel surfaces were cemented together with one of four cements [two GICs: Fuji I (GC), Ketac Cem Easymix (3M ESPE); two RMGICs: Fuji Plus (GC), RelyX Luting (3M ESPE)] in preparation for μTBS tests. Pre-treated enamel surfaces and cement-enamel interfaces were analyzed by scanning electron microscopy (SEM). Results: Phosphoric acid etching significantly increased the enamel μTBS of GICs/RMGICs. Conditioning with the liquids of the cements produced significantly weaker or equivalent enamel μTBS compared to the control. Regardless of etching, RMGICs yielded stronger enamel μTBS than GICs. A visible hybrid layer was found at certain enamel-cement interfaces of the etched enamels. Conclusions: Phosphoric acid etching significantly increased the enamel μTBSs of GICs/RMGICs. Phosphoric acid etching should be recommended to etch the enamel margins before the cementation of the prostheses such as inlays and onlays, using GICs/RMGICs to improve the bond strengths. RMGICs provided stronger enamel bond strength than GICs and conditioning did not increase enamel bond strength. PMID:24190447

Separation and Recovery of Cobalt from Copper Leach Solutions

NASA Astrophysics Data System (ADS)

Jeffers, T. H.

1985-01-01

Significant amounts of cobalt, a strategic and critical metal, are present in readily accessible copper recycling leach solutions. However, cost-effective technology is not available to separate and recover the cobalt from this low-grade domestic source. The Bureau of Mines has developed a procedure using a chelating ion-exchange resin from Dow Chemical Co. to successfully extract cobalt from a pH 3.0 copper recycling solution containing only 30 mg/1 cobalt. Cyclic tests with the commercial resin XFS-4195 in 4-ft-high by 1-in.-diameter columns gave an average cobalt extraction of 95% when 65 bed volumes of solution were processed at a flow rate of 4 gpm/ft.2 Elution of the cobalt using a 50 g/l H2SO4 solution yielded an eluate containing 0.5 gli Co. Selective elution of the loaded resin and solvent extraction procedures using di-2-ethylhexyl phosphoric acid (D2EHPA) and Cyanex 272 removed the impurities and produced a cobalt sulfate solution containing 25 g/l Co.

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.

Optical property investigations of polystyrene capped Ca{sub 2}P{sub 2}O{sub 7}:Dy{sup 3+} persistent phosphor

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

Jain, Abhilasha, E-mail: abhilasha.vnit@gmail.com; Kumar, Ashwini; Dhoble, S.J

2015-10-15

Highlights: • Synthesis of polymer capped pyrophosphate phosphors by citrate gel method. • Radiative lifetime is calculated from parameters of Judd-Ofelt theory and ICP-AES. • Reaction mechanism is discussed leading to high photoluminescence efficiency. • PL emission spectrum reveals broad band emission suitable for solid state lighting. - Abstract: By virtue of enhanced photosensivity, good optical response and better thermal stability, organic–inorganic hybrid materials are contemplated as one of the alternatives for designing advanced optoelectronic devices and innovative photonic applications. A novel inorganic organic hybrid Ca{sub 2}P{sub 2}O{sub 7}:Dy{sup 3+} phosphor has been fabricated by Pechini method. The optical propertymore » of synthesized phosphor is successfully altered by the in corporation of polystyrene sulfonic acid as capping agent in the colloidal solution. The phase purity and the average particle size of the prepared phosphor were calculated from X-ray diffraction (XRD) employing Debye Scherrer method. The morphological and chemical investigations were carried out through scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) analysis. The radiative transitions are explained on the basis of Judd-Ofelt theory and on the basis of derived parameters, the radiative lifetime of persistent hybrid Ca{sub 2}P{sub 2}O{sub 7}:Dy{sup 3+} phosphor is calculated as 5.33 ms. This paper explores the mechanism leading to high photoluminescence efficiency using organic capping additives. The photoluminescence (PL) graphs reveal broad band emission at 482 nm (blue) and 573 nm (yellow) corresponding to {sup 4}F{sub 9/2}-{sup 6}H{sub 15/2} and {sup 4}F{sub 9/2}-{sup 6}H{sub 13/2} transitions of Dy{sup 3+}, respectively. The Commission International De I-Eclairage (CIE) chromaticity co-ordinates were calculated from emission spectra and the values (x, y) were approaching to standard value of white emission. The synthesized pyrophosphate phosphors can thereby account in multiple potential applications including white light emitting diodes.« less

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

Zheng, Zhang; Wanjun, Tang, E-mail: tangmailbox@126.com

Highlights: • Iso-structural garnet-type Na{sub 2}(Y,Eu)Mg{sub 2}V{sub 3}O{sub 12} solid solution were synthesized. • Efficient energy transfer from [VO{sub 4}]{sup 3−} to Eu{sup 3+} ions in this phosphor is observed obviously. • Tuning the Y/Eu ratio generates the varied hues from yellowish-green to reddish-orange. • This kind of phosphor can be potentially used in UV pumped LEDs. - Abstract: A series of solid-solution phosphors Na{sub 2}(Y,Eu)Mg{sub 2}V{sub 3}O{sub 12} were prepared using solution combustion reaction. X-ray diffraction studies verified the formation of single phase Na{sub 2}(Y,Eu)Mg{sub 2}V{sub 3}O{sub 12} with garnet structure. Na{sub 2}(Y,Eu)Mg{sub 2}V{sub 3}O{sub 12} phosphors show notmore » only a broad emission band with a maximum at 510 nm due to the [VO{sub 4}]{sup 3−} group but also several sharp emission lines due to the Eu{sup 3+} ions. The energy transfer from [VO{sub 4}]{sup 3−} to Eu{sup 3+} was discussed on the base of the spectral analysis. The color-tunable emissions of the Na{sub 2}(Y,Eu)Mg{sub 2}V{sub 3}O{sub 12} phosphor as a function of Y/Eu ratio are realized by continuously generating the varied hues from yellowish-green to reddish-orange. This indicates that the obtained phosphor may have potential applications in the field of UV-based white LEDs.« less

Diphasic acido-basic properties of D(octylphenyl)phosphoric acid (DOPPA)

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

Sella, C.; Cote, G.; Bauer, D.

1995-07-01

In the first part of this work, the diphasic acido-basic constant (pka*) of di(octylphenyl)phosphoric acid, denoted hereafter DOPPA or HL, is determined from its experimental diphasic neutralization curve. The pka* value of DOPPA appears to be equal to 2.6 in the presence of 1 mol/dm{sup 3} sodium salt. Such a value is significantly lower than that previously determined for di(2-ethylhexyl) phosphoric acid (DEHPA, pka* = 5.2), 2-ethylhexylphosphonic acid, mono-2-ethylhexyl ester (PC88A, pka* = 7.1) and di(2,4,4-trimethylpentyl)phosphinic acid (CYANEX 272, pka* = 8.7). DOPPA (HL) is definitely more acidic than the other organophosphorus acids because its acidic proton can be easilymore » exchanged with sodium cation to form Na{sup +}HL{sub 2}{sup -} species in organic phase. In the second and final part of the work, molecular modelling is used to model the dimers of various organophosphorus acids. A structure-activity relationship is obtained between the association energies of modelled dimers and their diphasic acido-basic constants. This relationship is then used for predicting the pka* values of DOPPOA and DOPPIA which are the phosphonic and phosphinic analogs of DOPPA, respectively. 16 refs., 5 figs., 4 tabs.« less

Optimization of cellulose nanocrystal length and surface charge density through phosphoric acid hydrolysis

NASA Astrophysics Data System (ADS)

Vanderfleet, Oriana M.; Osorio, Daniel A.; Cranston, Emily D.

2017-12-01

Cellulose nanocrystals (CNCs) are emerging nanomaterials with a large range of potential applications. CNCs are typically produced through acid hydrolysis with sulfuric acid; however, phosphoric acid has the advantage of generating CNCs with higher thermal stability. This paper presents a design of experiments approach to optimize the hydrolysis of CNCs from cotton with phosphoric acid. Hydrolysis time, temperature and acid concentration were varied across nine experiments and a linear least-squares regression analysis was applied to understand the effects of these parameters on CNC properties. In all but one case, rod-shaped nanoparticles with a high degree of crystallinity and thermal stability were produced. A statistical model was generated to predict CNC length, and trends in phosphate content and zeta potential were elucidated. The CNC length could be tuned over a relatively large range (238-475 nm) and the polydispersity could be narrowed most effectively by increasing the hydrolysis temperature and acid concentration. The CNC phosphate content was most affected by hydrolysis temperature and time; however, the charge density and colloidal stability were considered low compared with sulfuric acid hydrolysed CNCs. This study provides insight into weak acid hydrolysis and proposes `design rules' for CNCs with improved size uniformity and charge density. This article is part of a discussion meeting issue `New horizons for cellulose nanotechnology'.

Phosphoric acid functionalized pre-sintered meso-silica for high temperature proton exchange membrane fuel cells.

PubMed

Zeng, Jie; He, Beibei; Lamb, Krystina; De Marco, Roland; Shen, Pei Kang; Jiang, San Ping

2013-05-21

An inorganic proton exchange membrane based on sintered mesoporous silica and phosphoric acid was developed with a high proton conductivity of 0.06 S cm(-1) at 200 °C, achieving an excellent power output of 689 mW cm(-2) in H2 at 190 °C and 200 mW cm(-2) in methanol at 200 °C with no external humidification.

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-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 uses...

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-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 uses...

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-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 uses...

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 uses...

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 uses...

NMR Studies of Mass Transport in New Conducting Media for Fuel Cells

DTIC Science & Technology

2009-01-01

PEM films, for example those containing phosphoric acid and ionic liquids . Dynamical processes are probed at the short range by spin-lattice...structural environments of muticomponent PEM films, for example those containing phosphoric acid and ionic liquids . Dynamical processes are probed at the...correlation between water diffusivity and proton conductivity in the nanocomposites Transport properties of several ionic liquids (IL’s) and membranes

Influence of different pre-etching times on fatigue strength of self-etch adhesives to dentin.

PubMed

Takamizawa, Toshiki; Barkmeier, Wayne W; Tsujimoto, Akimasa; Suzuki, Takayuki; Scheidel, Donal D; Erickson, Robert L; Latta, Mark A; Miyazaki, Masashi

2016-04-01

The purpose of this study was to use shear bond strength (SBS) and shear fatigue strength (SFS) testing to determine the influence on dentin bonding of phosphoric acid pre-etching times before the application of self-etch adhesives. Two single-step self-etch universal adhesives [Prime & Bond Elect (EL) and Scotchbond Universal (SU)], a conventional single-step self-etch adhesive [G-aenial Bond (GB)], and a two-step self-etch adhesive [OptiBond XTR (OX)] were used. The SBS and SFS values were obtained with phosphoric acid pre-etching times of 3, 10, or 15 s before application of the adhesives, and for a control without pre-etching. For groups with 3 s of pre-etching, SU and EL showed higher SBS values than control groups. No significant difference was observed for GB among the 3 s, 10 s, and control groups, but the 15 s pre-etching group showed significantly lower SBS and SFS values than the control group. No significant difference was found for OX among the pre-etching groups. Reducing phosphoric acid pre-etching time can minimize the adverse effect on dentin bonding durability for the conventional self-etch adhesives. Furthermore, a short phosphoric acid pre-etching time enhances the dentin bonding performance of universal adhesives. © 2016 Eur J Oral Sci.

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.

Removal of ammonia from landfill leachate by struvite precipitation with the use of low-cost phosphate and magnesium sources.

PubMed

Huang, Haiming; Xiao, Dean; Zhang, Qingrui; Ding, Li

2014-12-01

This paper presents a study concerning ammonia removal from landfill leachate by struvite precipitation with the use of waste phosphoric acid as the phosphate source. The results indicated that the Al(3+) ions present in the waste phosphoric acid significantly affected the struvite precipitation, and a removal ratio of ammonia close to that of pure phosphate salts could be achieved. Nevertheless, large amounts of NaOH were necessary to neutralize the H(+) present in the waste phosphoric acid. To overcome this problem, a low-cost magnesium source was proposed to be used as well as an alkali reagent in the struvite precipitation. The ammonia removal ratios were found to be 83%, with a remaining phosphate of 56 mg/L, by dosing the low-cost MgO in the Mg:N:P molar ratio of 3:1:1. An economic analysis showed that using waste phosphoric acid plus the low-cost MgO could save chemical costs by 68% compared with the use of pure chemicals. Post-treatment employment of a biological anaerobic filter process demonstrated that the high concentration of Mg(2+) remaining in the effluent of the struvite precipitation has no inhibitory effect on the performance of the biological treatment. Copyright © 2014 Elsevier Ltd. All rights reserved.

Preparation of silver-activated zinc sulfide thin films

NASA Technical Reports Server (NTRS)

Feldman, C.; Swindells, F. E.

1968-01-01

Silver improves luminescence and reduces contamination of zinc sulfide phosphors. The silver is added after the zinc sulfide phosphors are deposited in thin films by vapor evaporation, but before calcining, by immersion in a solution of silver salt.

Evaluation of Scotchbond Multipurpose and maleic acid as alternative methods of bonding orthodontic brackets.

PubMed

Olsen, M E; Bishara, S E; Damon, P; Jakobsen, J R

1997-05-01

Damage to the enamel surface during bonding and debonding of orthodontic brackets is a clinical concern. Alternative bonding methods that minimize enamel surface damage while maintaining a clinically useful bond strength is an aim of current research. The purpose of this study was to compare the effects on bond strength and bracket failure location of two adhesives (System 1+ and Scotchbond Multipurpose, 3M Dental Products Division) and two enamel conditioners (37% phosphoric acid and 10% maleic acid). Forty-eight freshly extracted human premolars were pumiced and divided into four groups of 12 teeth, and metal orthodontic brackets were attached to the enamel surface by one of four protocols: (1) System 1+ and phosphoric acid, (2) Scotchbond and phosphoric acid, (3) System 1+ and maleic acid, and (4) Scotchbond and maleic acid. After bracket attachment, the teeth were mounted in phenolic rings and stored in deionized water at 37 degrees C for 72 hours. A Zwick universal testing machine (Zwick GmbH & Co.) was used to determine shear bond strengths. The residual adhesive on the enamel surface was evaluated with the Adhesive Remnant Index. The analysis of variance was used to compare the four groups. Significance was predetermined at p < or = 0.05. The results indicated that there were no significant differences in bond strength among the four groups (p = 0.386). The results of the Chi square test, evaluating the residual adhesives on the enamel surfaces, revealed significant differences among the four groups (mean 2 = 0.005). A Duncan multiple range test revealed the difference occurred between the phosphoric acid and maleic acid groups, with maleic acid having bond failures at the enamel-adhesive interface. In conclusion, the use of Scotchbond Multipurpose and/or maleic acid does not significantly effect bond strength, however, the use of maleic acid resulted in an unfavorable bond failure location.

Removal of mercury bonded in residual glass from spent fluorescent lamps.

PubMed

Rey-Raap, Natalia; Gallardo, Antonio

2013-01-30

The current technologies available for recycling fluorescent lamps do not completely remove the phosphor powder attached to the surface of the glass. Consequently, the glass contains the mercury diffused through the glass matrix and the mercury deposited in the phosphor powder that has not been removed during treatment at the recycling plant. A low-cost process, with just one stage, which can be used to remove the layer of phosphor powder attached to the surface of the glass and its mercury was studied. Several stirring tests were performed with different extraction mixtures, different liquid-solid ratios, and different agitation times. The value of the initial mercury concentration of the residual glass was 2.37 ± 0.50 μg/g. The maximum extraction percentage was 68.38%, obtained by stirring for 24 h with a liquid-solid ratio of 10 and using an extraction solution with 5% of an acid mixture prepared with HCl and HNO(3) at a ratio of 3:1 by volume. On an industrial scale the contact time could be reduced to 8 h without significantly lowering the percentage of mercury extracted. In fact, 64% of the mercury was extracted. Copyright © 2012 Elsevier Ltd. All rights reserved.

Submicron diameter single crystal sapphire optical fiber

DOE PAGES

Hill, Cary; Homa, Daniel; Liu, Bo; ...

2014-10-02

In this work, a submicron-diameter single crystal sapphire optical fiber was demonstrated via wet acid etching at elevated temperatures. Etch rates on the order 2.3 µm/hr were achievable with a 3:1 molar ratio sulfuric-phosphoric acid solution maintained at a temperature of 343°C. A sapphire fiber with an approximate diameter of 800 nm was successfully fabricated from a commercially available fiber with an original diameter of 50 µm. The simple and controllable etching technique provides a feasible approach to the fabrication of unique waveguide structures via traditional silica masking techniques. The ability to tailor the geometry of sapphire optical fibers ismore » the first step in achieving optical and sensing performance on par with its fused silica counterpart.« less

Toward a universal carbonate clumped isotope calibration: Diverse synthesis and preparatory methods suggest a single temperature relationship

NASA Astrophysics Data System (ADS)

Kelson, Julia R.; Huntington, Katharine W.; Schauer, Andrew J.; Saenger, Casey; Lechler, Alex R.

2017-01-01

Carbonate clumped isotope (Δ47) thermometry has been applied to a wide range of problems in earth, ocean and biological sciences over the last decade, but is still plagued by discrepancies among empirical calibrations that show a range of Δ47-temperature sensitivities. The most commonly suggested causes of these discrepancies are the method of mineral precipitation and analytical differences, including the temperature of phosphoric acid used to digest carbonates. However, these mechanisms have yet to be tested in a consistent analytical setting, which makes it difficult to isolate the cause(s) of discrepancies and to evaluate which synthetic calibration is most appropriate for natural samples. Here, we systematically explore the impact of synthetic carbonate precipitation by replicating precipitation experiments of previous workers under a constant analytical setting. We (1) precipitate 56 synthetic carbonates at temperatures of 4-85 °C using different procedures to degas CO2, with and without the use of the enzyme carbonic anhydrase (CA) to promote rapid dissolved inorganic carbon (DIC) equilibration; (2) digest samples in phosphoric acid at both 90 °C and 25 °C; and (3) hold constant all analytical methods including acid preparation, CO2 purification, and mass spectrometry; and (4) reduce our data with 17O corrections that are appropriate for our samples. We find that the CO2 degassing method does not influence Δ47 values of these synthetic carbonates, and therefore probably only influences natural samples with very rapid degassing rates, like speleothems that precipitate out of drip solution with high pCO2. CA in solution does not influence Δ47 values in this work, suggesting that disequilibrium in the DIC pool is negligible. We also find the Δ47 values of samples reacted in 25 and 90 °C acid are within error of each other (once corrected with a constant acid fractionation factor). Taken together, our results show that the Δ47-temperature relationship does not measurably change with either the precipitation methods used in this study or acid digestion temperature. This leaves phosphoric acid preparation, CO2 gas purification, and/or data reduction methods as the possible sources of the discrepancy among published calibrations. In particular, the use of appropriate 17O corrections has the potential to reduce disagreement among calibrations. Our study nearly doubles the available synthetic carbonate calibration data for Δ47 thermometry (adding 56 samples to the 74 previously published samples). This large population size creates a robust calibration that enables us to examine the potential for calibration slope aliasing due to small sample size. The similarity of Δ47 values among carbonates precipitated under such diverse conditions suggests that many natural samples grown at 4-85 °C in moderate pH conditions (6-10) may also be described by our Δ47-temperature relationship.

Reduction and Analysis of Phosphor Thermography Data With the IHEAT Software Package

NASA Technical Reports Server (NTRS)

Merski, N. Ronald

1998-01-01

Detailed aeroheating information is critical to the successful design of a thermal protection system (TPS) for an aerospace vehicle. This report describes NASA Langley Research Center's (LaRC) two-color relative-intensity phosphor thermography method and the IHEAT software package which is used for the efficient data reduction and analysis of the phosphor image data. Development of theory is provided for a new weighted two-color relative-intensity fluorescence theory for quantitatively determining surface temperatures on hypersonic wind tunnel models; an improved application of the one-dimensional conduction theory for use in determining global heating mappings; and extrapolation of wind tunnel data to flight surface temperatures. The phosphor methodology at LaRC is presented including descriptions of phosphor model fabrication, test facilities and phosphor video acquisition systems. A discussion of the calibration procedures, data reduction and data analysis is given. Estimates of the total uncertainties (with a 95% confidence level) associated with the phosphor technique are shown to be approximately 8 to 10 percent in the Langley's 31-Inch Mach 10 Tunnel and 7 to 10 percent in the 20-Inch Mach 6 Tunnel. A comparison with thin-film measurements using two-inch radius hemispheres shows the phosphor data to be within 7 percent of thin-film measurements and to agree even better with predictions via a LATCH computational fluid dynamics solution (CFD). Good agreement between phosphor data and LAURA CFD computations on the forebody of a vertical takeoff/vertical lander configuration at four angles of attack is also shown. In addition, a comparison is given between Mach 6 phosphor data and laminar and turbulent solutions generated using the LAURA, GASP and LATCH CFD codes. Finally, the extrapolation method developed in this report is applied to the X-34 configuration with good agreement between the phosphor extrapolation and LAURA flight surface temperature predictions. The phosphor process outlined in the paper is believed to provide the aerothermodynamic community with a valuable capability for rapidly obtaining (4 to 5 weeks) detailed heating information needed in TPS design.

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.

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.

The mechanism of proton conduction in phosphoric acid

NASA Astrophysics Data System (ADS)

Vilčiauskas, Linas; Tuckerman, Mark E.; Bester, Gabriel; Paddison, Stephen J.; Kreuer, Klaus-Dieter

2012-06-01

Neat liquid phosphoric acid (H3PO4) has the highest intrinsic proton conductivity of any known substance and is a useful model for understanding proton transport in other phosphate-based systems in biology and clean energy technologies. Here, we present an ab initio molecular dynamics study that reveals, for the first time, the microscopic mechanism of this high proton conductivity. Anomalously fast proton transport in hydrogen-bonded systems involves a structural diffusion mechanism in which intramolecular proton transfer is driven by specific hydrogen bond rearrangements in the surrounding environment. Aqueous media transport excess charge defects through local hydrogen bond rearrangements that drive individual proton transfer reactions. In contrast, strong, polarizable hydrogen bonds in phosphoric acid produce coupled proton motion and a pronounced protic dielectric response of the medium, leading to the formation of extended, polarized hydrogen-bonded chains. The interplay between these chains and a frustrated hydrogen-bond network gives rise to the high proton conductivity.

Phosphoric acid fuel cell 1.3 MW plant in Milan

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

Colombo, M.; Vigano, A.

1997-07-01

At the end of the 80`s Aem, ENEA and Ansaldo Ricerche began to design and build a 1.3 MW phosphoric-acid-fuel-cell power plant for the production of electrical power and heat; this plant was built and installed in the Bicocca site, in the north-east area of Milan, where a great development is being promoted. Aem has been taking over the plant since July 1995. Its aim is to test the extensively advantages of this technology for both conversion efficiency and low environmental impact. The experimentation will have to recognize the key elements in order to plan and create the multi-megawatt plantsmore » with the phosphoric acid technology, opening the experimentation to international partners, like users, industries and Universities interested in the development and the application of these new systems of energy cogeneration.« less

Physical-Mechanical Properties and Micromorphology of Calcium Cements Exposed to Polyacrylic and Phosphoric Acids.

PubMed

de Souza, Gustavo Fernandes; Arrais, Ana Beatriz; Aragão, Cícero Flávio Soares; Ferreira, Isana Alvares; Borges, Boniek Castillo Dutra

2018-01-01

To evaluate if physical and mechanical properties of self-curing calcium hydroxide cements were affected by contact with polyacrylic and phosphoric acids. Resin-containing (Life (LF)) and resin-free (Hydro C (HyC)) materials were subjected to polyacrylic acid conditioning and rinsing (POL); phosphoric acid conditioning and rinsing (PHO); rinsing only; and no treatment ( n = 10). Water sorption/solubility, release of hydroxyl ions (pH), roughness (Ra), and impact resistance were evaluated. Additional samples ( n = 1) were prepared for scanning electron microscopy (SEM) analysis of the surface morphology. Data were analyzed by two-way ANOVA and Tukey post hoc test ( P < 0.05). Water sorption was significantly higher for LF when in contact with PHO and lower for POL ( P < 0.05). The mean solubility was higher with POL for both cements ( P < 0.05). PHO increased the mean surface roughness for HyC ( P < 0.01); a significant decrease was noted for LF after contact with both acids ( P < 0.01). PHO promoted lower release of hydroxyl ions on both cements ( P < 0.05). For LF, rinsing, PHO, and POL presented similar morphology, differing from the control group. For HyC, PHO and POL presented similar morphology, differing from the control group. PHO had a negative effect on the physical properties of the cements tested, except for the solubility test. POL affected roughness and solubility of HyC cement. Clinical procedures that require polyacrylic and phosphoric acid conditioning must be done carefully on self-curing calcium hydroxide cements in order to avoid negative impact on their properties.

Four chemical methods of porcelain conditioning and their influence over bond strength and surface integrity

PubMed Central

Stella, João Paulo Fragomeni; Oliveira, Andrea Becker; Nojima, Lincoln Issamu; Marquezan, Mariana

2015-01-01

OBJECTIVE: To assess four different chemical surface conditioning methods for ceramic material before bracket bonding, and their impact on shear bond strength and surface integrity at debonding. METHODS: Four experimental groups (n = 13) were set up according to the ceramic conditioning method: G1 = 37% phosphoric acid etching followed by silane application; G2 = 37% liquid phosphoric acid etching, no rinsing, followed by silane application; G3 = 10% hydrofluoric acid etching alone; and G4 = 10% hydrofluoric acid etching followed by silane application. After surface conditioning, metal brackets were bonded to porcelain by means of the Transbond XP system (3M Unitek). Samples were submitted to shear bond strength tests in a universal testing machine and the surfaces were later assessed with a microscope under 8 X magnification. ANOVA/Tukey tests were performed to establish the difference between groups (α= 5%). RESULTS: The highest shear bond strength values were found in groups G3 and G4 (22.01 ± 2.15 MPa and 22.83 ± 3.32 Mpa, respectively), followed by G1 (16.42 ± 3.61 MPa) and G2 (9.29 ± 1.95 MPa). As regards surface evaluation after bracket debonding, the use of liquid phosphoric acid followed by silane application (G2) produced the least damage to porcelain. When hydrofluoric acid and silane were applied, the risk of ceramic fracture increased. CONCLUSIONS: Acceptable levels of bond strength for clinical use were reached by all methods tested; however, liquid phosphoric acid etching followed by silane application (G2) resulted in the least damage to the ceramic surface. PMID:26352845

Preparation before colonoscopy: a randomized controlled trial comparing different regimes.

PubMed

Jansen, Sita V; Goedhard, Jelle G; Winkens, Bjorn; van Deursen, Cees Th B M

2011-10-01

A good bowel preparation is essential for optimal visualization of the large intestine. Several preparations with a difference in composition and volume are available. We compared five methods for bowel cleansing quality and patients' acceptability. Adult ambulatory outpatients scheduled for elective colonoscopy were randomized to receive 4-l polyethylene glycol (PEG) solution (Klean-prep), 2-l PEG solution+ascorbic acid (Moviprep), or a sodium phosphate (NaP) solution, Phosphoral. Patients with the PEG solutions were also randomized to receive simethicone (Aeropax), to investigate whether this improves the bowel cleansing efficacy. Before colonoscopy patients completed a questionnaire about the acceptability and tolerability of the preparation. Endoscopists blinded to the type of preparation gave a bowel cleansing score. Data were available for 461 patients. 2-l PEG+ascorbic acid was noninferior to 4-l PEG in bowel cleansing quality of rectosigmoid and colon. NaP was noninferior to 4-l PEG in bowel cleansing quality of rectosigmoid but inferior for the whole colon. Compliance was significantly less in the group with 4-l PEG compared with the 2-l PEG and NaP group. No difference was found for abdominal cramps. Taste was significantly better in the 2-l PEG group. Simethicone did not improve the bowel cleansing quality. 2-l PEG+ascorbic acid was noninferior to the 4-l PEG solution in bowel cleansing quality and was better in taste and compliance. NaP was inferior to 4-l PEG in bowel cleansing quality. Addition of simethicone gave no improvement.

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

PubMed

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

2011-10-15

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. Copyright © 2011 Elsevier B.V. All rights reserved.

Photodissociation of Gaseous Ions Formed by Laser Desorption.

DTIC Science & Technology

1986-09-20

produced by separate pathways from the (M-I)- ion or from consecutive photodissociations. Hesperidin : In the negative ion LD mass spectrum of this compound...an ion of m/z r𔃼 was produced from the sodium salt of hesperidin phosphoric acid ester. This ion was observed to dissociate by loss of the attached...Experimental conditions are same as in the top spectrum. Figure 8. Top. Negative ions formed by laser desorption from Na-salt of hesperidin phosphoric acid ester

Phosphoric acid electric utility fuel cell technology development

NASA Astrophysics Data System (ADS)

Breault, R. D.; Briggs, T. A.; Congdon, J. V.; Demarche, T. E.; Gelting, R. L.; Goller, G. J.; Luoma, W. L.; McCloskey, M. W.; Mientek, A. P.; Obrien, J. J.

1991-04-01

The major objective of this effort was the advancement of cell and stack technology required to meet performance and cost criteria for fabrication and operation of a prototype large area, full height phosphoric acid fuel cell stack. The performance goal for the cell stack corresponded to a power density of 150 wsf, and the manufactured cost goal was a 510 $/kW reduction (in 1981 dollars) compared to existing 3.7 ft.(exp 2) active area cell stacks.

Combinatorial synthesis of phosphors using arc-imaging furnace

PubMed Central

Ishigaki, Tadashi; Toda, Kenji; Yoshimura, Masahiro; Uematsu, Kazuyoshi; Sato, Mineo

2011-01-01

We have applied a novel ‘melt synthesis technique’ rather than a conventional solid-state reaction to rapidly synthesize phosphor materials. During a synthesis, the mixture of oxides or their precursors is melted by light pulses (10–60 s) in an arc-imaging furnace on a water-cooled copper hearth to form a globule of 1–5 mm diameter, which is then rapidly cooled by turning off the light. Using this method, we synthesized several phosphor compounds including Y3Al5O12:Ce(YAG) and SrAl2O4:Eu,Dy. Complex phosphor oxides are difficult to produce by conventional solid-state reaction techniques because of the slow reaction rates among solid oxides; as a result, the oxides form homogeneous compounds or solid solutions. On the other hand, melt reactions are very fast (10–60 s) and result in homogeneous compounds owing to rapid diffusion and mixing in the liquid phase. Therefore, melt synthesis techniques are suitable for preparing multi component homogeneous compounds and solid solutions. PMID:27877432

Combinatorial synthesis of phosphors using arc-imaging furnace

NASA Astrophysics Data System (ADS)

Ishigaki, Tadashi; Toda, Kenji; Yoshimura, Masahiro; Uematsu, Kazuyoshi; Sato, Mineo

2011-10-01

We have applied a novel 'melt synthesis technique' rather than a conventional solid-state reaction to rapidly synthesize phosphor materials. During a synthesis, the mixture of oxides or their precursors is melted by light pulses (10-60 s) in an arc-imaging furnace on a water-cooled copper hearth to form a globule of 1-5 mm diameter, which is then rapidly cooled by turning off the light. Using this method, we synthesized several phosphor compounds including Y3Al5O12:Ce(YAG) and SrAl2O4:Eu,Dy. Complex phosphor oxides are difficult to produce by conventional solid-state reaction techniques because of the slow reaction rates among solid oxides; as a result, the oxides form homogeneous compounds or solid solutions. On the other hand, melt reactions are very fast (10-60 s) and result in homogeneous compounds owing to rapid diffusion and mixing in the liquid phase. Therefore, melt synthesis techniques are suitable for preparing multi component homogeneous compounds and solid solutions.

Process for removal of ammonia and acid gases from contaminated waters

DOEpatents

King, C. Judson; MacKenzie, Patricia D.

1985-01-01

Contaminating basic gases, i.e., ammonia, and acid gases, e.g., carbon dioxide, are removed from process waters or waste waters in a combined extraction and stripping process. Ammonia in the form of ammonium ion is extracted by an immiscible organic phase comprising a liquid cation exchange component, especially an organic phosphoric acid derivative, and preferably di-2-ethyl hexyl phosphoric acid, dissolved in an alkyl hydrocarbon, aryl hydrocarbon, higher alcohol, oxygenated hydrocarbon, halogenated hydrocarbon, and mixtures thereof. Concurrently, the acidic gaseous contaminants are stripped from the process or waste waters by stripping with steam, air, nitrogen, or the like. The liquid cation exchange component has the ammonia stripped therefrom by heating, and the component may be recycled to extract additional amounts of ammonia.

Process for removal of ammonia and acid gases from contaminated waters

DOEpatents

King, C.J.; Mackenzie, P.D.

1982-09-03

Contaminating basic gases, i.e., ammonia and acid gases, e.g., carbon dioxide, are removed from process waters or waste waters in a combined extraction and stripping process. Ammonia in the form of ammonium ion is extracted by an immiscible organic phase comprising a liquid cation exchange component, especially an organic phosphoric acid derivative, and preferably di-2-ethyl hexyl phosphoric acid, dissolved in an alkyl hydrocarbon, aryl hydrocarbon, higher alcohol, oxygenated hydrocarbon, halogenated hydrocarbon, and mixtures thereof. Concurrently, the acidic gaseous contaminants are stripped from the process or waste waters by stripping with stream, air, nitrogen, or the like. The liquid cation exchange component has the ammonia stripped therefrom by heating, and the component may be recycled to extract additional amounts of ammonia.

Study on effective thermal conductivity of silicone/phosphor composite and its size effect by Lattice Boltzmann method

NASA Astrophysics Data System (ADS)

Li, Lan; Zheng, Huai; Yuan, Chao; Hu, Run; Luo, Xiaobing

2016-12-01

The silicone/phosphor composite is widely used in light emitting diode (LED) packaging. The composite thermal properties, especially the effective thermal conductivity, strongly influence the LED performance. In this paper, a lattice Boltzmann model was presented to predict the silicone/phosphor composite effective thermal conductivity. Based on the present lattice Boltzmann model, a random generation method was established to describe the phosphor particle distribution in composite. Benchmarks were conducted by comparing the simulation results with theoretical solutions for simple cases. Then the model was applied to analyze the effective thermal conductivity of the silicone/phosphor composite and its size effect. The deviations between simulation and experimental results are <7 %, when the phosphor volume fraction varies from 0.038 to 0.45. The simulation results also indicate that effective thermal conductivity of the composite with larger particles is higher than that with small particles at the same volume fraction. While mixing these two sizes of phosphor particles provides an extra enhancement for the effective thermal conductivity.

Molecular commonality detection using an artificial enzyme membrane for in situ one-stop biosurveillance.

PubMed

Ikeno, Shinya; Asakawa, Hitoshi; Haruyama, Tetsuya

2007-08-01

Biodetection and biosensing have been developed based on the concept of sensitivity toward specific molecules. However, current demand may require more levelheaded or far-sighted methods, especially in the field of biological safety and security. In the fields of hygiene, public safety, and security including fighting bioterrorism, the detection of biological contaminants, e.g., microorganisms, spores, and viruses, is a constant challenge. However, there is as yet no sophisticated method of detecting such contaminants in situ without oversight. The authors focused their attention on diphosphoric acid anhydride, which is a structure common to all biological phosphoric substances. Interestingly, biological phosphoric substances are peculiar substances present in all living things and include many different substances, e.g., ATP, ADP, dNTP, pyrophosphate, and so forth, all of which have a diphosphoric acid anhydride structure. The authors took this common structure as the basis of their development of an artificial enzyme membrane with selectivity for the structure common to all biological phosphoric substances and studied the possibility of its application to in situ biosurveillance sensors. The artificial enzyme membrane-based amperometric biosensor developed by the authors can detect various biological phosphoric substances, because it has a comprehensive molecular selectivity for the structure of these biological phosphoric substances. This in situ detection method of the common diphosphoric acid anhydride structure brings a unique advantage to the fabrication of in situ biosurveillance sensors for monitoring biological contaminants, e.g., microorganism, spores, and viruses, without an oversight, even if they were transformed.

The effect of a lignosulphate type additive on the lead—acid battery positive plate reactions

NASA Astrophysics Data System (ADS)

Ovuru, S. E.; Harrison, J. A.

The electrochemical formation of lead dioxide has been investigated at a lead electrode in a 5 M sulphuric acid solution, and in the presence of phosphoric acid and lignosulphate-type additive. The formation of lead dioxide from lead sulphate, and the reverse reaction, have been investigated by the linear potential sweep method, by an impedance method in which the impedance was measured at the end of each pulse during a potential pulse train, and by a charging curve method in which the current and charge was measured during a similar potential pulse train. The charge measurements prove that the main effect of the additive is to decrease the accompanying oxygen evolution reaction. The impedance measurements, however, show that the additive has a small but significant effect on the structure of the solid lead sulphate and lead dioxide layers.

On the Reaction of Carbonyl Diphosphonic Acid with Hydroxylamine and O-alkylhydroxylamines: Unexpected Degradation of P-C-P Bridge.

PubMed

Khomich, Olga A; Yanvarev, Dmitry V; Novikov, Roman A; Kornev, Alexey B; Puljulla, Elina; Vepsäläinen, Jouko; Khomutov, Alex R; Kochetkov, Sergey N

2017-06-23

Derivatives of methylenediphosphonic acid possess wide spectra of biological activities and are used in enzymology as research tools as well as in practical medicine. Carbonyl diphosphonic acid is a promising starting building block for synthesis of functionally substituted methylenediphosphonates. Investigation of the interaction of carbonyl diphosphonic acid with hydroxylamine clearly demonstrates that it is impossible to isolate oxime within the pH range 2-12, while only cyanophosphonic and phosphoric acids are the products of the fast proceeding Beckmann-like fragmentation. In the case of O -alkylhydroxylamines, corresponding alcohols are found in the reaction mixtures in addition to cyanophosphonic and phosphoric acids. Therefore, two residues of phosphonic acid being attached to a carbonyl group provide new properties to this carbonyl group, making its oximes very unstable. This principally differs carbonyl diphosphonic acid from structurally related phosphonoglyoxalic acid and other α-ketophosphonates.

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

Characterizing the correlation between dephosphorization and solution pH in a calcined water treatment plant sludge.

PubMed

Zhou, Zhenming; Liu, Qidi; Li, Shuwen; Li, Fei; Zou, Jing; Liao, Xiaobin; Yuan, Baoling; Sun, Wenjie

2018-04-26

This study focused on characterizing the correlation between the dephosphorization process of calcined water treatment plant sludge (C-WTPS) and the solution initial pH in batch experiments. The specific aim was to illustrate the effect of different initial pH on the adsorption and desorption of phosphorous in C-WTPS. In addition, the effects of solution initial pH on the release of ammonia nitrogen and total organic carbon (TOC) from C-WTPS and the change of pH after adsorption were also investigated. The results demonstrated that the initial pH significantly influenced the adsorption of phosphorus on C-WTPS. When initial pH was increased from 3 to 10, the phosphorous absorption capacity reduced by 76.5%. Especially, when the initial pH reached to 11, the phosphorus adsorption capacity became a negative value, indicating that C-WTPS released phosphorus into the solution. The addition of C-WTPS to the solution had little impact on the initial pH of the solution. The absorbed phosphorous on C-WTPS was relatively stable in the pH range of 3 to 10. Nevertheless, when the solution pH was higher than 11, it can be easily released into the solution. Furthermore, by comparison with WTPS, C-WTPS released less ammonia nitrogen and TOC into the solution and adsorbed more phosphorus from the solution in the experimental pH range. Therefore, C-WTPS is more suitable to serve as a cost-effective sorbent for phosphorus removal.

Influence of phosphoric acid on the electrochemistry of lead electrodes in sulfuric acid electrolyte containing antimony

NASA Astrophysics Data System (ADS)

Venugopalan, S.

The influence of phosphoric acid (0 to 40 g 1 -1) on the Pb/PbSO 4 reaction and the kinetics of hydrogen evolution on pure, smooth lead and lead alloy electrodes is studied via galvanostatic polarization in the linear and Tafel domains with and without antimony (0 to 10 mg 1 -1) addition to the H 2SO 4 (3 to 10 M) electrolyte. Phosphoric acid is found to offset significantly the adverse effect of antimony. H 3PO 4 is also found to increase the hydrogen overpotential without affecting the Pb/PbSO 4 reaction. This implies that the open-circuit corrosion of lead and the consequent hydrogen evolution rate on lead are reduced in the presence of H 3PO 4. The beneficial effects of H 3PO 4 additive are found to be optimum at around 20 g 1 -1. Suppression of hydrogen evolution on the negative electrode, a crucial criterion for sealed cell operation, can be achieved using a H 3PO 4 additive.

Large volume sample stacking of positively chargeable analytes in capillary zone electrophoresis without polarity switching: use of low reversed electroosmotic flow induced by a cationic surfactant at acidic pH.

PubMed

Quirino, J P; Terabe, S

2000-01-01

A simple and effective way to improve detection sensitivity of positively chargeable analytes in capillary zone electrophoresis more than 100-fold is described. Cationic species were made to migrate toward the cathode even under reversed electroosmotic flow caused by a cationic surfactant by using a low pH run buffer. For the first time, with such a configuration, large volume sample stacking of cationic analytes is achieved without a polarity-switching step and loss of efficiency. Samples are prepared in water or aqueous acetonitrile. Aromatic amines and a variety of drugs were concentrated using background solutions containing phosphoric acid and cetyltrimethylammonium bromide. Qualitative and quantitative aspects are also investigated.

Influence of anodization parameters on the morphology of TiO 2 nanotube arrays

NASA Astrophysics Data System (ADS)

Omidvar, Hamid; Goodarzi, Saba; Seif, Ahmad; Azadmehr, Amir R.

2011-07-01

TiO 2 nanotube arrays can be fabricated by electrochemical anodization in organic and inorganic electrolytes. Morphology of these nanotube arrays changes when anodization parameters such as applied voltage, type of electrolyte, time and temperature are varied. Nanotube arrays fabricated by anodization of commercial titanium in electrolytes containing NH 4F solution and either sulfuric or phosphoric acid were studied at room temperature; time of anodization was kept constant. Applied voltage, fluoride ion concentration, and acid concentrations were varied and their influences on TiO 2 nanotubes were investigated. The current density of anodizing was recorded by computer controlled digital multimeter. The surface morphology (top-view) of nanotube arrays were observed by SEM. The nanotube arrays in this study have inner diameters in range of 40-80 nm.

Light weight phosphate cements

DOEpatents

Wagh, Arun S.; Natarajan, Ramkumar,; Kahn, David

2010-03-09

A sealant having a specific gravity in the range of from about 0.7 to about 1.6 for heavy oil and/or coal bed methane fields is disclosed. The sealant has a binder including an oxide or hydroxide of Al or of Fe and a phosphoric acid solution. The binder may have MgO or an oxide of Fe and/or an acid phosphate. The binder is present from about 20 to about 50% by weight of the sealant with a lightweight additive present in the range of from about 1 to about 10% by weight of said sealant, a filler, and water sufficient to provide chemically bound water present in the range of from about 9 to about 36% by weight of the sealant when set. A porous ceramic is also disclosed.

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.

Chiral phosphoric acid catalysis: from numbers to insights.

PubMed

Maji, Rajat; Mallojjala, Sharath Chandra; Wheeler, Steven E

2018-02-19

Chiral phosphoric acids (CPAs) have emerged as powerful organocatalysts for asymmetric reactions, and applications of computational quantum chemistry have revealed important insights into the activity and selectivity of these catalysts. In this tutorial review, we provide an overview of computational tools at the disposal of computational organic chemists and demonstrate their application to a wide array of CPA catalysed reactions. Predictive models of the stereochemical outcome of these reactions are discussed along with specific examples of representative reactions and an outlook on remaining challenges in this area.

Effect of bromelain and papain gel on enamel deproteinisation before orthodontic bracket bonding.

PubMed

Pithon, Matheus Melo; Campos, Matheus Souza; Coqueiro, Raildo da Silva

2016-05-01

To test the hypothesis that enamel surface deproteinisation with different concentrations of bromelain in association with 10% papain increases the shear bond strength (SBS) of brackets bonded with orthodontic composite and resin modified glass ionomer cement (RMGIC). Orthodontic brackets were attached according to the following protocols to 195 bovine incisors, which were acquired and divided into 13 groups: 1) Transbond XT (TXT) according to the manufacturer's recommendations; 2) Deproteinisation with 3% bromelain (BD) plus 10% papain and TXT; 3) 6% BD plus 10% Papain and TXT; 4) RMGIC, without enamel deproteinisation and without acid etching; 5) RMGIC, with 3% BD plus 10% papain and without acid etching; 6) RMGIC, with 6% BD plus 10% papain and without acid etching; 7) attachment using RMGIC following etching with polyacrylic acid; 8) 3% BD plus 10% papain, attachment using RMGIC and etching with polyacrylic acid; 9) 6% BD plus 10% papain, and attachment using RMGIC following etching with polyacrylic acid; 10) etching with 37% phosphoric acid and attachment using RMGIC; 11) 3% BD plus 10% papain, etching with 37% phosphoric acid and attachment using RMGIC; 12) 6% BD plus 10% papain, etching with 37% phosphoric acid and attachment using RMGIC; 13) deproteinisation with 2.5% sodium hypochlorite (NaOCl), etching with polyacrylic acid and RMGIC. After bonding, the brackets were removed by a universal mechanical testing machine, which recorded shear bond strength at failure. The material remaining on the tooth was assessed using the adhesive remnant index (ARI). Deproteinisation with 3% and 6% bromelain gel plus papain significantly increased the shear bond strength (p < 0.05), when acid etching was performed with phosphoric acid, followed by primer application and attachment using Transbond XT (Group 3) and when attached with RMGIC without etching. Deproteinisation with 6% bromelain gel plus papain significantly increased (p < 0.05) the ARI score only when attachment was performed using RMGIC, without etching (Group 6). Deproteinisation with bromelain associated with papain in a gel increased the shear bond strength and is recommended before orthodontic bracket attachment.

Rapid Mix Preparation of Bioinspired Nanoscale Hydroxyapatite for Biomedical Applications

PubMed Central

Wilcock, Caroline J.; Gentile, Piergiorgio; Hatton, Paul V.; Miller, Cheryl A.

2017-01-01

Hydroxyapatite (HA) has been widely used as a medical ceramic due to its good biocompatibility and osteoconductivity. Recently there has been interest regarding the use of bioinspired nanoscale hydroxyapatite (nHA). However, biological apatite is known to be calcium-deficient and carbonate-substituted with a nanoscale platelet-like morphology. Bioinspired nHA has the potential to stimulate optimal bone tissue regeneration due to its similarity to bone and tooth enamel mineral. Many of the methods currently used to fabricate nHA both in the laboratory and commercially, involve lengthy processes and complex equipment. Therefore, the aim of this study was to develop a rapid and reliable method to prepare high quality bioinspired nHA. The rapid mixing method developed was based upon an acid-base reaction involving calcium hydroxide and phosphoric acid. Briefly, a phosphoric acid solution was poured into a calcium hydroxide solution followed by stirring, washing and drying stages. Part of the batch was sintered at 1,000 °C for 2 h in order to investigate the products' high temperature stability. X-ray diffraction analysis showed the successful formation of HA, which showed thermal decomposition to β-tricalcium phosphate after high temperature processing, which is typical for calcium-deficient HA. Fourier transform infrared spectroscopy showed the presence of carbonate groups in the precipitated product. The nHA particles had a low aspect ratio with approximate dimensions of 50 x 30 nm, close to the dimensions of biological apatite. The material was also calcium deficient with a Ca:P molar ratio of 1.63, which like biological apatite is lower than the stoichiometric HA ratio of 1.67. This new method is therefore a reliable and far more convenient process for the manufacture of bioinspired nHA, overcoming the need for lengthy titrations and complex equipment. The resulting bioinspired HA product is suitable for use in a wide variety of medical and consumer health applications. PMID:28287572

Rapid Mix Preparation of Bioinspired Nanoscale Hydroxyapatite for Biomedical Applications.

PubMed

Wilcock, Caroline J; Gentile, Piergiorgio; Hatton, Paul V; Miller, Cheryl A

2017-02-23

Hydroxyapatite (HA) has been widely used as a medical ceramic due to its good biocompatibility and osteoconductivity. Recently there has been interest regarding the use of bioinspired nanoscale hydroxyapatite (nHA). However, biological apatite is known to be calcium-deficient and carbonate-substituted with a nanoscale platelet-like morphology. Bioinspired nHA has the potential to stimulate optimal bone tissue regeneration due to its similarity to bone and tooth enamel mineral. Many of the methods currently used to fabricate nHA both in the laboratory and commercially, involve lengthy processes and complex equipment. Therefore, the aim of this study was to develop a rapid and reliable method to prepare high quality bioinspired nHA. The rapid mixing method developed was based upon an acid-base reaction involving calcium hydroxide and phosphoric acid. Briefly, a phosphoric acid solution was poured into a calcium hydroxide solution followed by stirring, washing and drying stages. Part of the batch was sintered at 1,000 °C for 2 h in order to investigate the products' high temperature stability. X-ray diffraction analysis showed the successful formation of HA, which showed thermal decomposition to β-tricalcium phosphate after high temperature processing, which is typical for calcium-deficient HA. Fourier transform infrared spectroscopy showed the presence of carbonate groups in the precipitated product. The nHA particles had a low aspect ratio with approximate dimensions of 50 x 30 nm, close to the dimensions of biological apatite. The material was also calcium deficient with a Ca:P molar ratio of 1.63, which like biological apatite is lower than the stoichiometric HA ratio of 1.67. This new method is therefore a reliable and far more convenient process for the manufacture of bioinspired nHA, overcoming the need for lengthy titrations and complex equipment. The resulting bioinspired HA product is suitable for use in a wide variety of medical and consumer health applications.

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. Copyright © 2016 Elsevier Ltd. All rights reserved.

Evaluation of Mineral Content and Photon Interaction Parameters of Dental Enamel After Phosphoric Acid and Er:YAG Laser Treatment.

PubMed

Simsek, Huseyin; Gurbuz, Taskın; Buyuk, Suleyman Kutalmış; Ozdemir, Yuksel

2017-05-01

The purpose of this study was to evaluate the effects of laser and acid etching on the mineral content and photon interaction parameters of dental enamel in human teeth. The composition of dental enamel may vary, especially at the surface, depending on the reactions that occur during dental treatment. Forty maxillary premolars were divided randomly into 2 groups of 20 teeth. In the first group, half of teeth crowns were etched by using 37% phosphoric acid; in the second group, half of teeth crowns were etched by using an erbium:yttrium-aluminum-garnet (Er:YAG) laser. The remaining half crowns in each group were used as untreated controls. We characterized the calcium (Ca), phosphorus (P), magnesium (Mg), sodium (Na), and potassium (K) contents in each specimen by using wavelength dispersive X-ray fluorescence spectrometry. The total atomic cross-section ([Formula: see text]), effective atomic number ([Formula: see text]), and electron density (N e ) of the tooth samples were determined at photon energies of 22.1, 25, 59.5, and 88 keV by using a narrow beam transmission method. Data were analyzed statistically by using the Mann-Whitney U test. The mineral contents after Er:YAG laser and phosphoric acid etching did not differ significantly (p > 0.05), and no significant variation in [Formula: see text], [Formula: see text], or N e was observed. Therefore, we conclude that the Er:YAG laser and phosphoric acid systems used in this study did not affect mineral composition or photon interaction parameters of dental enamel.

Reactivity of amine antioxidants relative to OH and anti e

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

Minkhadzhidinova, D.R.; Nikiforov, G.A.; Khrapova, N.G.

1986-06-20

An ESR study was carried out on the reactivity of various types of amines relative to OH/sup ./ and anti e. The selection of these compounds having anti-oxidant properties was also based on the circumstance that amine molecules contain a set of functional groups which may be potential sites for the attack of both OH and anti e radicals. A sample of 6 M H/sub 3/PO/sub 4/ was used for the matrix solutions and forms a glass upon rapid insertion into liquid nitrogen. The phosphoric acid solutions of these compounds taken in concentrations from 0.025 to 0.05 M were flushedmore » with argon to remove oxygen. Ampules containing the solutions were inserted into liquid nitrogen and irradiated from a cobalt source. The ESR spectra of the irradiated solutions clearly show the components of the atomic hydrogen doublet with a = 50 mT and of H/sub 2/PO/sub 4//sup ./ radicals in the central region of the spectrum.« less

Properties of blue emitting CaAl2O4:Eu2+, Nd3+ phosphor by optimizing the amount of flux and fuel

NASA Astrophysics Data System (ADS)

Wako, A. H.; Dejene, B. F.; Swart, H. C.

2014-04-01

Long afterglow CaAl2O4:0.03Eu2+, 0.03Nd3+ phosphor was prepared by solution-combustion synthesis. The active role of boric acid (H3BO3) as a flux in enhancing the Eu2+ photoluminescence and the effect of a varied amount of urea (CO (NH2)2) as a fuel on the morphological, structural and photoluminescent (PL) properties of the CaAl2O4:0.03Eu2+, 0.03Nd3+ systems were investigated. The results of X-ray diffraction, scanning electron microscopy, and PL spectra revealed the influence of the dosage of urea and hence the heated process on the crystallinity, morphology, and luminescence of the phosphor. The addition of H3BO3 favoured the formation of a monoclinic CaAl2O4 phase while the variation of the amount of CO (NH2)2 showed mixed phases although still predominantly monoclinic. Both H3BO3 and CO(NH2)2 to some extent influence the luminescence intensity of the obtained phosphor but unlike the case of CO(NH2)2, the presence of H3BO3 did not evidently shift the emission peak due to no obvious change in the energy level difference of the 4f-5d levels. The broad blue emissions consisting mainly of symmetrical bands having maxima between 440 and 445 nm originate from the energy transitions between the ground state (4f7) and the excited state (4f65d1) of the Eu2+ ions while the narrow emissions in the red region (600-630 nm) arise from the 5D0→7F2 transitions of the remnant unreduced Eu3+ions. Higher concentrations of H3BO3 (0.228 mol and 0.285 mol) reduce both intensity and lifetime of the phosphor. The optimized content of H3BO3 was 0.171 mol for the obtained phosphor with the best optical properties.

The Variation of Root Exudates from the Hyperaccumulator Sedum alfredii under Cadmium Stress: Metabonomics Analysis

PubMed Central

Luo, Qing; Sun, Lina; Hu, Xiaomin; Zhou, Ruiren

2014-01-01

Hydroponic experiments were conducted to investigate the variation of root exudates from the hyperaccumulator Sedum alfredii under the stress of cadmium (Cd). S. alfredii was cultured for 4 days in the nutrient solution spiked with CdCl2 at concentrations of 0, 5, 10, 40, and 400 µM Cd after the pre-culture. The root exudates were collected and analyzed by GC-MS, and 62 compounds were identified. Of these compounds, the orthogonal partial least-squares discrimination analysis (OPLS-DA) showed that there were a distinct difference among the root exudates with different Cd treatments and 20 compounds resulting in this difference were found out. Changing tendencies in the relative content of these 20 compounds under the different Cd treatments were analyzed. These results indicated that trehalose, erythritol, naphthalene, d-pinitol and n-octacosane might be closely related to the Cd stabilization, phosphoric acid, tetradecanoic acid, oxalic acid, threonic acid and glycine could be attributed to the Cd mobilization, and mannitol, oleic acid, 3-hydroxybutanoic acid, fructose, octacosanol and ribitol could copy well with the Cd stress. PMID:25545686

Removal of azo dye by a highly graphitized and heteroatom doped carbon derived from fish waste: Adsorption equilibrium and kinetics.

PubMed

Liu, Zhengang; Zhang, Fang; Liu, Tingting; Peng, Nana; Gai, Chao

2016-11-01

A highly graphitized and heteroatom doped porous carbon was prepared from fish waste in the present study. The morphology and chemical composition of the resultant porous carbon were characterized by SEM-EDS, TEM, BET, XRD and Raman measurement. The prepared porous carbon was employed as an adsorbent for acid orange 7, a typical azo dye, removal from aqueous solution. The results showed that the porous carbon had ultrahigh surface area of 2146 m(2)/g, a high degree of graphitization structure and naturally doped with nitrogen and phosphorous. The maximum adsorption capacity of acid orange 7 reached 285.71 mg/g due to unique property of the prepared porous carbon. In addition, acid orange 7 adsorption onto the porous carbon well followed pseudo-second-order kinetics model and acid orange 7 diffusion in micropores was the potential rate controlling step. Copyright © 2016 Elsevier Ltd. All rights reserved.

A new sensor for thermometric titrations.

PubMed

Najib, Fadhil M; Zewar, Sardir; Abdulla, Ahmad M

2007-01-15

A new thermometric sensor, which is a transistor (OC71), has been introduced to follow thermometric titrations successfully to clear end points. The sensor was suitable in both normal and differential modes of titration. It is possible to titrate down to 1.32micromol of HCl and 26.4micromol of H(3)BO(3)in a final 20ml solution with accuracy and precision of 1%, 2.2% and 1.4%, 2.2%, respectively. The sensor, in association with a pH glass electrode, was used for the determination of pK values of some well established weak acids such as, acetic acid (4.77), phosphoric acid (pK(1)=2.18, pK(2)=7.20 and pK(3)=12.32) as well as for a very weak acid of uncertain pK values H(3)BO(3) (pK(1)=9.20, pK(2)=12.7 and pK(3)=13.80). The sensor was also examined for kinetic catalytic determination of iron(III) in water, milk and pharmaceuticals.

Fuzzy Multicriteria Ranking of Aluminium Coating Methods

NASA Astrophysics Data System (ADS)

Batzias, A. F.

2007-12-01

This work deals with multicriteria ranking of aluminium coating methods. The alternatives used are: sulfuric acid anodization, A1; oxalic acid anodization, A2; chromic acid anodization, A3; phosphoric acid anodization, A4; integral color anodizing, A5; chemical conversion coating, A6; electrostatic powder deposition, A7. The criteria used are: cost of production, f1; environmental friendliness of production process, f2; appearance (texture), f3; reflectivity, f4; response to coloring, f5; corrosion resistance, f6; abrasion resistance, f7; fatigue resistance, f8. Five experts coming from relevant industrial units set grades to the criteria vector and the preference matrix according to a properly modified Delphi method. Sensitivity analysis of the ranked first alternative A1 against the `second best', which was A3 at low and A7 at high resolution levels proved that the solution is robust. The dependence of anodized products quality on upstream processes is presented and the impact of energy price increase on industrial cost is discussed.

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.

Advanced coal gasifier-fuel cell power plant systems design

NASA Technical Reports Server (NTRS)

Heller, M. E.

1983-01-01

Two advanced, high efficiency coal-fired power plants were designed, one utilizing a phosphoric acid fuel cell and one utilizing a molten carbonate fuel cell. Both incorporate a TRW Catalytic Hydrogen Process gasifier and regenerator. Both plants operate without an oxygen plant and without requiring water feed; they, instead, require makeup dolomite. Neither plant requires a shift converter; neither plant has heat exchangers operating above 1250 F. Both plants have attractive efficiencies and costs. While the molten carbonate version has a higher (52%) efficiency than the phosphoric acid version (48%), it also has a higher ($0.078/kWh versus $0.072/kWh) ten-year levelized cost of electricity. The phosphoric acid fuel cell power plant is probably feasible to build in the near term: questions about the TRW process need to be answered experimentally, such as weather it can operate on caking coals, and how effective the catalyzed carbon-dioxide acceptor will be at pilot scale, both in removing carbon dioxide and in removing sulfur from the gasifier.

Method of extracting iodine from liquid mixtures of iodine, water and hydrogen iodide

DOEpatents

Mysels, Karol J.

1979-01-01

The components of a liquid mixture consisting essentially of HI, water and at least about 50 w/o iodine are separated in a countercurrent extraction zone by treating with phosphoric acid containing at least about 90 w/o H.sub.3 PO.sub.4. The bottom stream from the extraction zone is substantially completely molten iodine, and the overhead stream contains water, HI, H.sub.3 PO.sub.4 and a small fraction of the amount of original iodine. When the water and HI are present in near-azeotropic proportions, there is particular advantage in feeding the overhead stream to an extractive distillation zone wherein it is treated with additional concentrated phosphoric acid to create an anhydrous HI vapor stream and bottoms which contain at least about 85 w/o H.sub.3 PO.sub.4. Concentration of these bottoms provides phosphoric acid infeed for both the countercurrent extraction zone and for the extractive distillation zone.

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.

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.

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.

Neodymium(III) Complexes of Dialkylphosphoric and Dialkylphosphonic Acids Relevant to Liquid-Liquid Extraction Systems

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

Lumetta, Gregg J.; Sinkov, Sergey I.; Krause, Jeanette A.

2016-01-27

The complexes formed during the extraction of neodymium(III) into hydrophobic solvents containing acidic organophosphorus extractants were probed by single-crystal X-ray diffractometry, visible spectrophotometry, and Fourier-transform infrared spectroscopy. The crystal structure of the compound Nd(DMP)3 (1, DMP = dimethyl phosphate) revealed a polymeric arrangement in which each Nd(III) center is surrounded by six DMP oxygen atoms in a pseudo-octahedral environment. Adjacent Nd(III) ions are bridged by (MeO)2POO– anions, forming the polymeric network. The diffuse reflectance visible spectrum of 1 is nearly identical to that of the solid that is formed when an n-dodecane solution of di-(2-ethylhexyl)phosphoric acid (HA) is saturated withmore » Nd(III), indicating a similar coordination environment around the Nd center in the NdA3 solid. The visible spectrum of the HA solution fully loaded with Nd(III) is very similar to that of the NdA3 material, both displaying hypersensitive bands characteristic of an pseudo-octahedral coordination environment around Nd. These spectral characteristics persisted across a wide range of organic Nd concentrations, suggesting that the pseudo-octahedral coordination environment is maintained from dilute to saturated conditions.« less

Comparative study on Ce (III) and La (III) solvent extraction and separation from a nitric acid medium by D2EHPA and Cyanex272

NASA Astrophysics Data System (ADS)

Habibpour, R.; Dargahi, M.; Kashi, E.; Bagherpour, M.

2018-01-01

The solvent extraction of Cerium(III) and Lanthanum(III) from nitric acid solution using the organophosphorous extractants Di-(2-ethyl hexyl) phosphate (D2EHPA) and di-2,4,4- trimethylpentyl phosphoric acid (Cyanex272) in kerosene was investigated. In this study, the magnitude of the extraction of Ce(III) was found to be more significant with Cyanex272 than D2EHPA. D2EHPA was found to be a better extractant for La(III). Among the two extractants, Cyanex272 was used for the separation of Ce from La in three stages with an extraction efficiency of 90.2% for Ce. A 556 mg/L Ce solution was used for the scrubbing of La with an efficiency of ≈34%, which required multi stage scrubbing. The study of thermodynamic parameters such as enthalpy, entropy, and Gibbs free energy impart the exothermic and non-spontaneous process. The chemical speciation curves for lanthanum and cerium in the aqueous phase as a function of pH showed that the free La(III) and Ce(III) metal ion species were largely predominate between a pH = 0 and pH = 7.

Neodymium(III) Complexes of Dialkylphosphoric and Dialkylphosphonic Acids Relevant to Liquid-Liquid Extraction Systems.

PubMed

Lumetta, Gregg J; Sinkov, Sergey I; Krause, Jeanette A; Sweet, Lucas E

2016-02-15

The complexes formed during the extraction of neodymium(III) into hydrophobic solvents containing acidic organophosphorus extractants were probed by single-crystal X-ray diffractometry, visible spectrophotometry, and Fourier-transform infrared spectroscopy. The crystal structure of the compound Nd(DMP)3 (1, DMP = dimethyl phosphate) revealed a polymeric arrangement in which each Nd(III) center is surrounded by six DMP oxygen atoms in a pseudo-octahedral environment. Adjacent Nd(III) ions are bridged by (MeO)2POO(-) anions, forming the polymeric network. The diffuse reflectance visible spectrum of 1 is nearly identical to that of the solid that is formed when an n-dodecane solution of di(2-ethylhexyl)phosphoric acid (HA) is saturated with Nd(III), indicating a similar coordination environment around the Nd center in the NdA3 solid. The visible spectrum of the HA solution fully loaded with Nd(III) is very similar to that of the NdA3 material, both displaying hypersensitive bands characteristic of an pseudo-octahedral coordination environment around Nd. These spectral characteristics persisted across a wide range of organic Nd concentrations, suggesting that the pseudo-octahedral coordination environment is maintained from dilute to saturated conditions.

Influence of variation in mobile phase pH and solute pK(a) with the change of organic modifier fraction on QSRRs of hydrophobicity and RP-HPLC retention of weakly acidic compounds.

PubMed

Han, Shu-ying; Liang, Chao; Zou, Kuan; Qiao, Jun-qin; Lian, Hong-zhen; Ge, Xin

2012-11-15

The variation in mobile phase pH and ionizable solute dissociation constant (pK(a)) with the change of organic modifier fraction in hydroorganic mobile phase has seemingly been a troublesome problem in studies and applications of reversed phase high performance liquid chromatography (RP-HPLC). Most of the early studies regarding the RP-HPLC of acid-base compounds have to measure the actual pH of the mixed mobile phase rigorously, sometimes bringing difficulties in the practices of liquid chromatographic separation. In this paper, the effect of this variation on the apparent n-octanol/water partition coefficient (K(ow)″) and the related quantitative structure-retention relationship (QSRR) of logK(ow)″ vs. logk(w), the logarithm of retention factor of analytes in neat aqueous mobile phases, was investigated for weakly acidic compounds. This QSRR is commonly used as a classical method for K(ow) measurement by RP-HPLC. The theoretical and experimental derivation revealed that the variation in mobile phase pH and solute pK(a) will not affect the QSRRs of acidic compounds. This conclusion is proved to be suitable for various types of ion-suppressors, i.e., strong acid (perchloric acid), weak acid (acetic acid) and buffer salt (potassium dihydrogen phosphate/phosphoric acid, PBS). The QSRRs of logK(ow)″ vs. logk(w) were modeled by 11 substituted benzoic acids using different types of ion-suppressors in a binary methanol-water mobile phase to confirm our deduction. Although different types of ion-suppressor all can be used as mobile phase pH modifiers, the QSRR model obtained by using perchloric acid as the ion-suppressor was found to have the best result, and the slightly inferior QSRRs were obtained by using acetic acid or PBS as the ion-suppressor. Copyright © 2012 Elsevier B.V. All rights reserved.

Prayon process for wet acid purification

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

Davister, A.; Peeterbroeck, M.

Described is a process developed in Belgium which enables the upgrading technical phosphoric acid to feed and food grades. After laboratory and pilot tests, Prayon developed and patented a solvent extraction process using a mixture of di-isopropyl ether and tributyl phosphate as solvent. The purified phosphoric acid obtained complies with the quality requirements of the market and can be used for metal treatments, in the manufacture of pure phosphates, for cattle feed, by the fermentation industry, for beverages, etc. Among the advantages of this process are its simplicity of operation, its low power consumption, and minimal environmental pollution. Extensive technologicalmore » data are given.« less

Self-etching adhesive on intact enamel, with and without pre-etching.

PubMed

Devarasa, G M; Subba Reddy, V V; Chaitra, N L; Swarna, Y M

2012-05-01

Bond strengths of composite resin to enamel using self-etch adhesive (SEA) Clearfil SE bond system on intact enamel and enamel pre-etched with phosphoric acid were compared. The objective was to determine if the pre-etching would increase the bond strengths of the SEA systems to intact enamel and to evaluate the effect of pre-etching on bond formation of self-etch adhesives on intact enamel. Labial surfaces of 40 caries free permanent upper central and lateral incisors were cleaned, sectioned of their roots. All specimens were mounted on acrylic block and divided randomly into four groups. In two groups the application of self-etch adhesive, Clearfil SE bond was carried as per manufacturer's instructions, composite cylinders were built, whereas in the other two groups, 37% phosphoric acid etching was done before the application of self-etching adhesives. Then the resin tags were analyzed using scanning electron microscope and shear bond strength was measured using Instron universal testing machine. When phosphoric acid was used, there was significant increase in the depth of penetration of resin tags and in the Shear Bond Strength of composite to enamel. The results indicate that out of both treatment groups, pre-etching the intact enamel with 37% phosphoric acid resulted in formation of longer resin tags and higher depth of penetration of resin tags of the Clearfil SE bond, and attaining higher bond strength of the Clearfil SE bond to intact enamel. Copyright © 2011 Wiley Periodicals, Inc.

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).

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.

Influence of Annealing Temperature and Gd and Eu Concentrations on Structure and Luminescence Properties of (Y,Gd)BO3:Eu3+ Phosphors Prepared by Sol-Gel Method

NASA Astrophysics Data System (ADS)

Lien, N. T. K.; Thang, N. V.; Hung, N. D.; Cuong, N. D.; Kien, N. D. T.; Thang, C. X.; Vuong, P. H.; Viet, D. X.; Khoi, N. T.; Huy, P. T.

2017-06-01

Red-emitting Eu3+-doped (Y,Gd)BO3 phosphors have been synthesized by a sol-gel process using metal oxides and boric acid as starting materials and citric acid as chelating agent. The main factors affecting the structure and luminescence properties of the product, such as sintering temperature, chemical composition, and Eu3+ doping concentration, were investigated. X-ray diffraction (XRD) analysis indicated that the phosphors begin to crystallize at sintering temperature of 700°C and become phase pure at 900°C. The average size of the phosphor particles after sintering at 1000°C was determined to be about 30 nm to 50 nm. The (Y,Gd)BO3:Eu3+ phosphors were found to exhibit strong red emission at 611 nm and 625 nm corresponding to the 5D0-7F2 transitions of Eu3+ in the host lattice. The photoluminescence intensity was enhanced by posttreatment at 900°C and remained unchanged at 1000°C. It was also found that the optimal concentration of Gd3+ ions for Eu3+ emission was 35%, and no concentration quenching of the photoluminescence was observed even at Eu3+ doping concentration up to 30%.

A comparative study of shear bond strength of orthodontic bracket after acid-etched and Er:YAG treatment on enamel surface

NASA Astrophysics Data System (ADS)

Leão, Juliana C.; Mota, Cláudia C. B. O.; Cassimiro-silva, Patricia F.; Gomes, Anderson S. L.

2016-02-01

This study aimed to evaluate the shear bond strength (SBS) of teeth prepared for orthodontic bracket bonding with 37% phosphoric acid and Er:YAG laser. Forty bovine incisors were divided into two groups. In Group I, the teeth were conditioned with 37% phosphoric acid and brackets were bonded with Transbond XT; in Group II, the teeth were irradiated with Er:YAG and bonding with Transbond XT. After SBS test, the adhesive remnant index was determined. Adhesion to dental hard tissues after Er:YAG laser etching was inferior to that obtained after acid etching but exceeded what is believed to be clinically sufficient strength, and therefore can be used in patients.

Ultraviolet /UV/ sensitive phosphors for silicon imaging detectors

NASA Technical Reports Server (NTRS)

Viehmann, W.; Cowens, M. W.; Butner, C. L.

1981-01-01

The fluorescence properties of UV sensitive organic phosphors and the radiometric properties of phosphor coated silicon detectors in the VUV, UV, and visible wavelengths are described. With evaporated films of coronene and liumogen, effective quantum efficiencies of up to 20% have been achieved on silicon photodiodes in the vacuum UV. With thin films of methylmethacrylate (acrylic), which are doped with organic laser dyes and deposited from solution, detector quantum efficiencies of the order of 15% for wavelengths of 120-165 nm and of 40% for wavelengths above 190 nm have been obtained. The phosphor coatings also act as antireflection coatings and thereby enhance the response of coated devices throughout the visible and near IR.

The quality study of recycled glass phosphor waste for LED

NASA Astrophysics Data System (ADS)

Tsai, Chun-Chin; Chen, Guan-Hao; Yue, Cheng-Feng; Chen, Cin-Fu; Cheng, Wood-Hi

2017-02-01

To study the feasibility and quality of recycled glass phosphor waste for LED packaging, the experiments were conducted to compare optical characteristics between fresh color conversion layer and that made of recycled waste. The fresh color conversion layer was fabricated through sintering pristine mixture of Y.A.G. powder [yellow phosphor (Y3AlO12 : Ce3+). Those recycled waste glass phosphor re-melted to form Secondary Molten Glass Phosphor (S.M.G.P.). The experiments on such low melting temperature glass results showed that transmission rates of S.M.G.P. are 9% higher than those of first-sintered glass phosphor, corresponding to 1.25% greater average bubble size and 36% more bubble coverage area in S.M.G.P. In the recent years, high power LED modules and laser projectors have been requiring higher thermal stability by using glass phosphor materials for light mixing. Nevertheless, phosphor and related materials are too expensive to expand their markets. It seems a right trend and research goal that recycling such waste of high thermal stability and quality materials could be preferably one of feasible cost-down solutions. This technical approach could bring out brighter future for solid lighting and light source module industries.

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

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

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 ionmore » 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)« less

High color rendering index WLED based on YAG:Ce phosphor and CdS/ZnS core/shell quantum dots

NASA Astrophysics Data System (ADS)

Shen, Changyu; Li, Ke

2009-08-01

White LED combining of blue chip and YAG:Ce phosphor suffers from a red spectral deficiency, resulting in a relatively low value of color rendering index (CRI). In our study, for an effort to improve color rendering properties of YAG:Ce phosphor-based white LEDs, highly luminescent red-orange emitting CdS/ZnS QDs were blended with YAG:Ce phosphors. Core/shell CdS/ZnS quantum dots with the emission wavelength of 618nm, was synthesized by thermal deposition using cadmium oxide and selenium as precursors in a hot lauric acid and hexadecylamine trioctylphosphine oxide hybrid. YAG:Ce phosphor was synthesized by high-temperature solid state reaction at 900-1200°C in a slightly reducing atmosphere for 4 hours. Blends of phosphors and QDs exhibited the prominent spectral evolution with an increasing content of QDs. A hybrid white LED, which combines a blue LED with the blend of YAG phosphor and QDs with a weight ratio of 1.5:1,was demonstrated with an improved CRI value of 86.

40 CFR 63.600 - Applicability.

Code of Federal Regulations, 2014 CFR

2014-07-01

... wet-process phosphoric acid process line: reactors, filters, evaporators, and hot wells; (2) Each... following emission points which are components of a superphosphoric acid process line: evaporators, hot...

Development of a rapid LC-DAD/FLD method for the simultaneous determination of auxins and abscisic acid in plant extracts.

PubMed

Bosco, Renato; Caser, Matteo; Vanara, Francesca; Scariot, Valentina

2013-11-20

Plant hormones play a crucial role in controlling plant growth and development. These groups of naturally occurring substances trigger physiological processes at very low concentrations, which mandate sensitive techniques for their quantitation. This paper describes a method to quantify endogenous (±)-2-cis-4-trans-abscisic acid, indole-3-acetic acid, indole-3-propionic acid, and indole-3-butyric acid. The method combines high-performance liquid chromatography (HPLC) with diode array and fluorescence detection in a single run. Hybrid tea rose 'Monferrato' matrices (leaves, petals, roots, seeds, androecium, gynoecium, and pollen) were used as references. Rose samples were separated and suspended in extracting methanol, after which (±)-2-cis-4-trans-abscisic acid and auxins were extracted by solvent extraction. Sample solutions were added first to cation solid phase extraction (SPE) cartridges and the eluates to anion SPE cartridges. The acidic hormones were bound to the last column and eluted with 5% phosphoric acid in methanol. Experimental results showed that this approach can be successfully applied to real samples and that sample preparation and total time for routine analysis can be greatly reduced.

Microwave Synthesis of BCNO/SiO2 Nanocomposite Material

NASA Astrophysics Data System (ADS)

Faryuni, I. D.; Ramdhani, F.; Sampurno, J.; Nuryadin, B. W.; Noor, F. A.; Iskandar, F.

2017-07-01

In the present work, we report the preparation of BCNO/SiO2 phosphor synthesized using a microwave-assisted method. This method allows a lower temperature and a shorter reaction time than simple heating (furnace). The phosphors were prepared from precursors containing, boric acid, urea, citric acid and SiO2 nanoparticles. To These precursors, silica nanoparticles were added at various concentrations from 0 to 5 %wt. The emission wavelength produced by the phosphor was varied by varying the fraction mass of the silica that were added to the precursors. The results showed that higher photoluminescence (PL) intensity was produced by the BCNO/SiO2 with 3 %wt silica addition. The novelty of this research is using microwave heating for BCNO/SiO2 synthesis, which is usually conducted using a simple heating method.

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.

Comparison of Four Strong Acids on the Precipitation Potential of Gypsum in Brines During Distillation of Pretreated, Augmented Urine

NASA Technical Reports Server (NTRS)

Muirhead, Dean

2011-01-01

Two batches of nominally pretreated and augmented urine were prepared with the baseline pretreatment formulation of sulfuric acid and chromium trioxide. The urine was augmented with inorganic salts and organic compounds in order to simulate a urinary ionic concentrations representing the upper 95 percentile on orbit. Three strong mineral acids: phosphoric, hydrochloric, and nitric acid, were substituted for the sulfuric acid for comparison to the baseline sulfuric acid pretreatment formulation. Three concentrations of oxidizer in the pretreatment formulation were also tested. Pretreated urine was distilled to 85% water recovery to determine the effect of each acid and its conjugate base on the precipitation of minerals during distillation. The brines were analyzed for calcium and sulfate ion, total, volatile, and fixed suspended solids. Test results verified that substitution of phosphoric, hydrochloric, or nitric acids for sulfuric acid would prevent the precipitation of gypsum up to 85% recovery from pretreated urine representing the upper 95 percentile calcium concentration on orbit.

Amine-functionalized, multi-arm star polymers: A novel platform for removing glyphosate from aqueous media.

PubMed

Samuel, Lianna; Wang, Ran; Dubois, Geraud; Allen, Robert; Wojtecki, Rudy; La, Young-Hye

2017-02-01

We describe a novel method for efficiently removing glyphosate from aqueous media via adsorption onto highly functionalized star-shaped polymeric particles. These particles have a polystyrene core with more than 35 attached methacrylate polymer arms, each containing a plurality of pendant amines (poly(dimethylamino ethyl methacrylate): PDMAEMA) that are partially protonated in water. Kinetic studies demonstrate that these star-polymers successfully remove up to 93% of glyphosate present in aqueous solution (feed concentration: 5 ppm), within 10 min contact time, outperforming activated carbon, which removed 33% after 20 min. On these star-polymers, glyphosate adsorption closely follows the Langmuir model indicating monolayer coverage at most. Ionic interaction between the protonated amines and glyphosate's dissociated carboxylic and phosphoric acid groups lead to effective glyphosate capture even at feed concentrations below 1 ppm. Surface charge of these star polymers and dissociation of glyphosate are both influenced by pH, thus glyphosate removal efficiency increases from 63% to 93% when pH increases from 4.2 to 7.7. NMR studies conducted with butylamine as a proxy for these polymeric particles confirm that the amine group binds with both glyphosate's carboxylic and phosphoric acid groups when its concentrations are in a 2:1 or higher molar ratio with glyphosate. Copyright © 2016 Elsevier Ltd. All rights reserved.

X-ray reflectivity study of formation of multilayer porous anodic oxides of silicon.

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

Chu, Y.; Fenollosa, R.; Parkhutik, V.

1999-07-21

The paper reports data on the kinetics of anodic oxide films growth on silicon in aqueous solutions of phosphoric acids as well as a study of the morphology of the oxides grown in a special regime of the oscillating anodic potential. X-ray reflectivity measurements were performed on the samples of anodic oxides using an intense synchrotron radiation source. They have a multilayer structure as revealed by theoretical fitting of the reflectivity data. The oscillations of the anodic potential are explained in terms of synchronized oxidation/dissolution reactions at the silicon surface and accumulation of mechanic stress in the oxide film.

Inorganic resist materials based on zirconium phosphonate for atomic force microscope lithography

NASA Astrophysics Data System (ADS)

Kang, Mankyu; Kim, Seonae; Jung, JinHyuck; Kim, Heebom; Shin, Inkyun; Jeon, Chanuk; Lee, Haiwon

2014-03-01

New inorganic resist materials based on metal complexes were investigated for atomic force microscope (AFM) lithography. Phosphoric acids are good for self-assembly because of their strong binding energy. In this work, zirconium phosphonate system are newly synthesized for spin-coatable materials in aqueous solutions and leads to negative tone pattern for improving line edge roughness. Low electron exposure by AFM lithography could generate a pattern by electrochemical reaction and cross-linking of metal-oxo complexes. It has been reported that the minimum pattern results are affected by lithographic speed, and the applied voltage between a tip and a substrate.

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.

Concentration and wavelength dependent frequency downshifting photoluminescence from a Tb3+ doped yttria nano-phosphor: A photochromic phosphor

NASA Astrophysics Data System (ADS)

Yadav, Ram Sagar; Rai, Shyam Bahadur

2018-03-01

In this article, the Tb3+ doped Y2O3 nano-phosphor has been synthesized through solution combustion method. The structural measurements of the nano-phosphor have been carried out by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques, which reveal nano-crystalline nature. The Fourier transform infrared (FTIR) measurements reveal the presence of different molecular species in the nano-phosphor. The UV-Vis-NIR absorption spectrum of the nano-phosphor shows large number of bands due to charge transfer band (CTB) and 4f-4f electronic transitions of Tb3+ ion. The Tb3+ doped Y2O3 nano-phosphor emits intense green downshifting photoluminescence centered at 543 nm due to 5D4 → 7F5 transition on excitation with 350 nm. The emission intensity of the nano-phosphor is optimized at 1.0 mol% concentration of Tb3+ ion. When the as-synthesized nano-phosphor is annealed at higher temperature the emission intensity of the nano-phosphor enhances upto 5 times. The enhancement in the emission intensity is due to an increase in crystallinity of the nano-phosphor, reduction in surface defects and optical quenching centers. The CIE diagram reveals that the Tb3+ doped nano-phosphor samples show the photochromic nature (color tunability) with a change in the concentration of Tb3+ ion and excitation wavelength. The lifetime measurement indicates an increase in the lifetime for the annealed sample. Thus, the Tb3+ doped Y2O3 nano-phosphor may be used in photochromic displays and photonic devices.

Polybenzimidazole membranes for direct methanol fuel cell: Acid-doped or alkali-doped?

NASA Astrophysics Data System (ADS)

Li, Long-Yun; Yu, Bor-Chern; Shih, Chao-Ming; Lue, Shingjiang Jessie

2015-08-01

Polybenzimidazole (PBI) films immersed in 2 M phosphoric acid (H3PO4) or 6 M potassium hydroxide (KOH) solution form electrolytes for conducting proton or hydroxide, respectively. A direct methanol fuel cell (DMFC) with the alkali-KOH doped PBI gives 117.9 mW cm-2 of power output which is more than 2 times greater than the power density of 46.5 mW cm-2 with the H3PO4-doped PBI (vs.) when both of the DMFCs use a micro porous layer (MPL) in a gas-fed cathode and a MPL-free anode and are operated at 90 °C. When the MPL-free anode and cathode are used and the fuel flow rate is tripled, the peak power density of alkaline DMFC reaches 158.9 mW cm-2.

Determination of Low Level Alpha and Beta Emitters Using Liquid-Liquid Extraction and a Liquid Scintillation Spectrometer

NASA Astrophysics Data System (ADS)

Yu, Yu-Fu; BjØRnstad, H. E.; Salbu, B.

Two radiochemical procedures for determination of low level strontium-90 and plutonium-239+240 in environmental and biological materials using combined selective solvent extraction with low level liquid scintillation counting have been presented. Y-90, the daughter nuclide of Sr-90, and Pu-239+240 are selectively extracted from nitric acid solution into 5% di(-2ethylhexyl)phosphoric acid (HDEHP) in toluene and the radionuclides of interest in organic phase are counted with an ultra low level scintillation counter "Quantulus". The lower detection limits for Sr-90 and Pu-239+240 are estimated to be 20 mBq and 0.3 mBq respectively. The developed procedures have been tested for soma environmental and biological samples and the preminarly results show that they are more simple and time-saving than traditional methods.

21 CFR 133.129 - Dry curd cottage cheese.

Code of Federal Regulations, 2014 CFR

2014-04-01

... of the following methods is employed: (i) Harmless lactic-acid-producing bacteria, with or without... pressed, chilled, worked, seasoned with salt; or (ii) Food grade phosphoric acid, lactic acid, citric acid..., seasoned with salt. (iii) Food grade acids as provided in paragraph (b)(1)(ii) of this section, D-Glucono...

21 CFR 133.129 - Dry curd cottage cheese.

Code of Federal Regulations, 2012 CFR

2012-04-01

... of the following methods is employed: (i) Harmless lactic-acid-producing bacteria, with or without... pressed, chilled, worked, seasoned with salt; or (ii) Food grade phosphoric acid, lactic acid, citric acid..., seasoned with salt. (iii) Food grade acids as provided in paragraph (b)(1)(ii) of this section, D-Glucono...

21 CFR 133.129 - Dry curd cottage cheese.

Code of Federal Regulations, 2013 CFR

2013-04-01

... of the following methods is employed: (i) Harmless lactic-acid-producing bacteria, with or without... pressed, chilled, worked, seasoned with salt; or (ii) Food grade phosphoric acid, lactic acid, citric acid..., seasoned with salt. (iii) Food grade acids as provided in paragraph (b)(1)(ii) of this section, D-Glucono...

Effects of coolant parameters on steady state temperature distribution in phospheric-acid fuel cell electrode

NASA Technical Reports Server (NTRS)

Alkasab, K. A.; Abdul-Aziz, A.

1991-01-01

The influence of thermophysical properties and flow rate on the steady-state temperature distribution in a phosphoric-acid fuel cell electrode plate was experimentally investigated. An experimental setup that simulates the operating conditions prevailing in a phosphoric-acid fuel cell stack was used. The fuel cell cooling system utilized three types of coolants to remove excess heat generated in the cell electrode and to maintain a reasonably uniform temperature distribution in the electrode plate. The coolants used were water, engine oil, and air. These coolants were circulated at Reynolds number ranging from 1165 to 6165 for water; 3070 to 6864 for air; and 15 to 79 for oil. Experimental results are presented.

Metal separation from mixed types of batteries using selective precipitation and liquid-liquid extraction techniques.

PubMed

Provazi, Kellie; Campos, Beatriz Amaral; Espinosa, Denise Crocce Romano; Tenório, Jorge Alberto Soares

2011-01-01

The purpose of this paper is to study metal separation from a sample composed of a mixture of the main types of spent household batteries, using a hydrometallurgical route, comparing selective precipitation and liquid-liquid extraction separation techniques. The preparation of the solution consisted of: grinding the waste of mixed batteries, reduction and volatile metals elimination using electric furnace and acid leaching. From this solution two different routes were studied: selective precipitation with sodium hydroxide and liquid-liquid extraction using Cyanex 272 [bis(2,4,4-trimethylpentyl) phosphoric acid] as extracting agent. The best results were obtained from liquid-liquid extraction in which Zn had a 99% extraction rate at pH 2.5. More than 95% Fe was extracted at pH 7.0, the same pH at which more than 90% Ce was extracted. About 88% Mn, Cr and Co was extracted at this pH. At pH 3.0, more than 85% Ni was extracted, and at pH 3.5 more than 80% of Cd and La was extracted. Copyright © 2010 Elsevier Ltd. All rights reserved.

Gallium metal affinity capture tandem mass spectrometry for the selective detection of phosphopeptides in complex mixtures

PubMed Central

Blacken, Grady R.; Sadílek, Martin; Tureček, František

2008-01-01

Metal affinity capture tandem mass spectrometry (MAC-MSMS) is evaluated in a comparative study of a lysine-derived nitrilotriacetic acid (Nα, Nα-bis-(carboxymethyl)lysine, LysNTA) and an aspartic-acid-related iminodiacetic acid (N-(4-aminobutyl)aspartic acid, AspIDA) as selective phosphopeptide detection reagents. Both LysNTA and AspIDA spontaneously form ternary complexes with GaIII and phosphorylated amino acids and phosphopeptides upon mixing in solution. Collision-induced dissociation of positive complex ions produced by electrospray produces common fragments (LysNTA + H)+ or (AspIDA + H)+ at m/z 263 and 205, respectively. MSMS precursor scans using these fragments as reporter ions allow one to selectively detect multiple charge states of phosphopeptides in mixtures. It follows from this comparative study that LysNTA is superior to AspIDA in detecting phosphopeptides, possibly because of the higher coordination number and greater stability constant for GaIII – phosphopeptide complexation of the former reagent. In a continuing development of MAC-MSMS for proteomics applications, we demonstrate its utility in a post-column reaction format. Using a simple post-column-reaction ‘T’ and syringe pump to deliver our chelating reagents, α-casein tryptic phosphopeptides can be selectively analyzed from a solution containing a twofold molar excess of bovine serum albumin. The MAC-MSMS method is shown to be superior to the commonly used neutral loss scan for the common loss of phosphoric acid. PMID:18265438

Reaction catalysts of urea-formaldehyde resin, as related to strength properties of southern pine particleboard

Treesearch

C. -Y. Hse

1974-01-01

Twelve resins were formulated with factorial combinations of three alkaline catalysts (i.e., somdium hydroxide, hexamethylenetetramine, and triethanolamine) and four acidic catalysts (i.e., acetic acid, hydrochloric acid, ammonium chloride, and phosphoric acid). The resins were replicated.

Facile solution-precipitation assisted synthesis and luminescence property of greenish-yellow emitting Ca{sub 6}Ba(PO{sub 4}){sub 4}O:Eu{sup 2+} phosphor

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

Ji, Haipeng; Huang, Zhaohui, E-mail: huang118@cugb.edu.cn; Xia, Zhiguo, E-mail: xiazg@ustb.edu.cn

2016-03-15

Highlights: • Ca{sub 6}Ba(PO{sub 4}){sub 4}O:Eu{sup 2+} phosphor was prepared by the solution-precipitation assisted route. • The phosphors have satisfactory smooth grain surface and particle size. • It shows greenish-yellow color emission (maximum at 540 nm) upon blue light excitation. • Eu{sup 2+} is coordinated with isolated oxygen atoms and those from PO{sub 4} polyhedra. - Abstract: Greenish-yellow emitting microcrystalline Ca{sub 6}Ba(PO{sub 4}){sub 4}O:Eu{sup 2+} phosphor was successfully prepared by a solution-precipitation assisted high temperature reaction method. Phase structure, morphology and/or luminescence properties of the precursor and the as-prepared phosphors were characterized. The phase-pure Ca{sub 6}Ba(PO{sub 4}){sub 4}O:Eu{sup 2+} phosphorsmore » were obtained with smooth grain surface and particle size of 2–8 μm. Ca{sub 6}Ba(PO{sub 4}){sub 4}O:Eu{sup 2+} exhibits bright greenish-yellow color emission with its maximum at 540 nm upon UV-blue light excitation. The maximum position of the broad emission band is independent on the calcination temperature. The emission intensity increases with increasing calcination temperature due to improved crystallinity. Besides, the presence of two Eu{sup 2+} emission centers in the Ca{sub 6}Ba(PO{sub 4}){sub 4}O crystal lattice was confirmed and the coordination effects are considered concerning the roles of isolated O atoms and those from the PO{sub 4} tetrahedra.« less

Influence of water storage on fatigue strength of self-etch adhesives.

PubMed

Takamizawa, Toshiki; Barkmeier, Wayne W; Tsujimoto, Akimasa; Scheidel, Donal D; Watanabe, Hidehiko; Erickson, Robert L; Latta, Mark A; Miyazaki, Masashi

2015-12-01

The purpose of this study was to determine enamel and dentin bond durability after long-term water storage using self-etch adhesives. Two single step self-etch adhesives (SU, Scotchbond Universal and GB, G-ӕnial Bond) and a two-step self-etch adhesive (OX, OptiBond XTR) were used. The shear bond strength (SBS) and shear fatigue strength (FS) of the enamel and dentin were obtained with and without phosphoric acid pre-etching prior to application of the adhesives. The specimens were stored in distilled water at 37 °C for 24 h, 6 months, and one year. A staircase method was used to determine the FS using a frequency of 10 Hz for 50,000 cycles or until failure occurred. The SBS and FS of enamel bonds were significantly higher with pre-etching, when compared to no pre-etching for the same water storage period. The FS of dentin bonds with pre-etching tended to decrease relative to no pre-etching at the same storage period. For the one year storage period, SU and GB with pre-etching showed significantly lower FS values than the groups without pre-etching. The influence of water storage on FS of the self-etch adhesives was dependent on the adhesive material, storage period and phosphoric acid pre-etching of the bonding site. Phosphoric acid pre-etching of enamel improves the effectiveness of self-etch adhesive systems. Inadvertent contact of phosphoric acid on dentin appears to reduce the ability of self-etch adhesives to effectively bond resin composite materials. Copyright © 2015 Elsevier Ltd. All rights reserved.

The development of Ce3+-activated (Gd,Lu)3Al5O12 garnet solid solutions as efficient yellow-emitting phosphors

NASA Astrophysics Data System (ADS)

Li, Jinkai; Li, Ji-Guang; Liu, Shaohong; Li, Xiaodong; Sun, Xudong; Sakka, Yoshio

2013-10-01

Ce3+-activated Gd3Al5O12 garnet, effectively stabilized by Lu3+ doping, has been developed for new yellow-emitting phosphors. The powder processing of [(Gd1-xLux)1-yCey]3Al5O12 solid solutions was achieved through precursor synthesis via carbonate precipitation, followed by annealing. The resultant (Gd,Lu)AG:Ce3+ phosphor particles exhibit typical yellow emission at ˜570 nm (5d-4f transition of Ce3+) upon blue-light excitation at ˜457 nm (the 2F5/2-5d transition of Ce3+). The quenching concentration of Ce3+ was determined to be ˜1.0 at% (y = 0.01) and the quenching mechanism was suggested to be driven by exchange interactions. The best luminescent [(Gd0.9Lu0.1)0.99Ce0.01]AG phosphor is comparative to the well-known YAG:Ce3+ in emission intensity but has a substantially red-shifted emission band that is desired for warm-white lighting. The effects of processing temperature (1000-1500 °C) on the spectroscopic properties of the phosphors, especially those of Lu3+/Ce3+, were thoroughly investigated and discussed from the centroid position and crystal field splitting of the Ce3+ 5d energy levels.

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.

Refining of crude rubber seed oil as a feedstock for biofuel production.

PubMed

Gurdeep Singh, Haswin Kaur; Yusup, Suzana; Abdullah, Bawadi; Cheah, Kin Wai; Azmee, Fathin Nabilah; Lam, Hon Loong

2017-12-01

Crude rubber seed oil is a potential source for biofuel production. However it contains undesirable impurities such as peroxides and high oxidative components that not only affect the oil stability, colour and shelf-life but promote insoluble gums formation with time that could cause deposition in the combustion engines. Therefore to overcome these problems the crude rubber seed oil is refined by undergoing degumming and bleaching process. The effect of bleaching earth dosage (15-40 wt %), phosphoric acid dosage (0.5-1.0 wt %) and reaction time (20-40 min) were studied over the reduction of the peroxide value in a refined crude rubber seed oil. The analysis of variance shows that bleaching earth dosage was the most influencing factor followed by reaction time and phosphoric acid dosage. A minimum peroxide value of 0.1 milliequivalents/gram was achieved under optimized conditions of 40 wt % of bleaching earth dosage, 1.0 wt % of phosphoric acid dosage and 20 min of reaction time using Response Surface Methodology design. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effects of a non-rinse conditioner on the enamel of primary teeth.

PubMed

Fava, Marcelo; Myaki, Silvio Issáo; Arana-Chavez, Victor Elias; Fava-de-Moraes, Flavio

2003-01-01

The aim of this in vitro study was to evaluate by scanning electron microscopy the morphological aspects of the enamel of primary teeth after etching with 36% phosphoric acid or a non-rinse conditioner. Ten naturally exfoliated anterior primary teeth were selected. The samples were subjected to prophylaxis with pumice paste and water using a low-speed hand piece. Etching was done on the buccal surface. Specimens were divided into 2 groups: G1 (n=10): etching with 36% phosphoric acid gel - Conditioner 36 (Dentsply) for 20 s, followed by water rinse for 15 s; G2 (n=10): etching with NRC - Non Rinse Conditioner (Dentsply) for 20 s, followed by air drying for 15 s. The samples were dehydrated, mounted on metal stubs, coated with gold and observed with Jeol JSM-6100 scanning electron microscope. Electron-micrographic analysis showed that both etching agents were effective for etching the enamel of primary teeth causing the formation of microporosities on the enamel surface, although the etching pattern was more effective with the use of 36% phosphoric acid gel.

Evaluation of efficient glucose release using sodium hydroxide and phosphoric acid as pretreating agents from the biomass of Sesbania grandiflora (L.) Pers.: A fast growing tree legume.

PubMed

Mund, Nitesh K; Dash, Debabrata; Barik, Chitta R; Goud, Vaibhav V; Sahoo, Lingaraj; Mishra, Prasannajit; Nayak, Nihar R

2017-07-01

Sesbania grandiflora (L.) Pers. is one of the fast growing tree legumes having the efficiency to produce around 50tha -1 above ground dry matters in a year. In this study, biomass of 2years old S. grandiflora was selected for the chemical composition, pretreatments and enzymatic hydrolysis studies. The stem biomass with a wood density of 3.89±0.01gmcm -3 contains about 38% cellulose, 12% hemicellulose and 28% lignin. Enzymatic hydrolysis of pretreated biomass revealed that phosphoric acid (H 3 PO 4 ) pretreated samples even at lower cellulase loadings [1 Filter Paper Units (FPU)], could efficiently convert about 86% glucose, while, even at higher cellulase loadings (60FPU) alkali pretreated biomass could convert only about 58% glucose. The effectiveness of phosphoric acid pretreatment was also supported by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and Fourier transform infrared spectroscopy (FTIR) analysis. Copyright © 2017 Elsevier Ltd. All rights reserved.

Chemical fingerprinting of valeriana species: simultaneous determination of valerenic acids, flavonoids, and phenylpropanoids using liquid chromatography with ultraviolet detection.

PubMed

Navarrete, Andres; Avula, Bharathi; Choi, Young-Whan; Khan, Ikhlas A

2006-01-01

The roots and rhizomes of various valeriana species are currently used as a sleeping aid or mild sedative. A liquid chromatography method has been developed that permits the analysis of chlorogenic acid, lignans, flavonoids, valerenic acids, and valpotrates in various valerian samples. The best results were obtained with a Phenomenex Luna C18(2) column using gradient elution with a mobile phase consisting of water and 0.05% phosphoric acid and 2-100% acetonitrile-methanol (1 + 1) with 0.05% phosphoric acid. The flow rate was 0.8 mL/min and ultraviolet detection was at 207, 225, 254, 280, and 325 nm. Different valerian species and commercial products showed remarkable quantitative variations. Chlorogenic acid (0.2-1.2%), 3 lignans, linarin (0.002-0.24%), and valepotriates were detected in all the valeriana species analyzed. Highest amounts of valerenic acids were detected in V. officinalis L., trace amounts in V. sitchensis, and none in the other species analyzed.

Method oil shale pollutant sorption/NO.sub.x reburning multi-pollutant control

DOEpatents

Boardman, Richard D [Idaho Falls, ID; Carrington, Robert A [Idaho Falls, ID

2008-06-10

A method of decreasing pollutants produced in a combustion process. The method comprises combusting coal in a combustion chamber to produce at least one pollutant selected from the group consisting of a nitrogen-containing pollutant, sulfuric acid, sulfur trioxide, carbonyl sulfide, carbon disulfide, chlorine, hydroiodic acid, iodine, hydrofluoric acid, fluorine, hydrobromic acid, bromine, phosphoric acid, phosphorous pentaoxide, elemental mercury, and mercuric chloride. Oil shale particles are introduced into the combustion chamber and are combusted to produce sorbent particulates and a reductant. The at least one pollutant is contacted with at least one of the sorbent particulates and the reductant to decrease an amount of the at least one pollutant in the combustion chamber. The reductant may chemically reduce the at least one pollutant to a benign species. The sorbent particulates may adsorb or absorb the at least one pollutant. A combustion chamber that produces decreased pollutants in a combustion process is also disclosed.

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. 2010 Elsevier Ltd. All rights reserved.

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.

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.

Compact regenerable sulfur scrubber for phosphoric acid fuel cells. Final report, 30 September 1986-30 September 1987

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

Giner, J.; Cropley, C.C.

Technology for the direct desulfurization of unprocessed diesel fuel using regenerable copper-based mixed metal oxide sorbents was developed for incorporation in modular phosphoric acid fuel cell (PAFC) generators. Removal of greater 60% of the sulfur in diesel fuel was demonstrated, and sorbent sulfur loadings of approximately 1 wt% were attained. Preliminary studies indicated that the sorbents are regenerable, with up to 70% of the sorbed sulfur removed during regeneration. Incorporation of this technology into a PAFC power plant should reduce the weight of the sulfur removal unit by a minimum of 25%.

21 CFR 172.841 - Polydextrose.

Code of Federal Regulations, 2014 CFR

2014-04-01

...-glucose, 10 percent sorbitol, and 1 percent citric acid or of approximately 90 percent D-glucose, 10 percent sorbitol, and 0.1 percent phosphoric acid, on a weight basis. (2) Polydextrose may be partially...

The role of phosphate additive in stabilization of sulphuric-acid-based vanadium(V) electrolyte for all-vanadium redox-flow batteries

NASA Astrophysics Data System (ADS)

Roznyatovskaya, Nataliya V.; Roznyatovsky, Vitaly A.; Höhne, Carl-Christoph; Fühl, Matthias; Gerber, Tobias; Küttinger, Michael; Noack, Jens; Fischer, Peter; Pinkwart, Karsten; Tübke, Jens

2017-09-01

Catholyte in all-vanadium redox-flow battery (VRFB) which consists of vanadium salts dissolved in sulphuric acid is known to be stabilized by phosphoric acid to slow down the thermal aging at temperatures higher than 40 °C. To reveal the role of phosphoric acid, the thermally-induced aggregation is investigated using variable-temperature 51V, 31P, 17O, 1H nuclear magnetic resonance (NMR) spectroscopy and dynamic light scattering (DLS). The results indicate that the thermal stabilization of vanadium(V) electrolyte is attained by the involvement of monomeric and dimeric vanadium(V) species in the reaction with phosphoric acid which is concurrent to the formation of neutral hydroxo-aqua vanadium(V) precipitation precursor. The dimers are stabilized by counter ions due to association reaction or if such stabilization is not possible, precipitation of vanadium pentoxide is favored. The evolution of particles size distributions at 50 °C in electrolyte samples containing 1.6 M vanadium and 4.0 M total sulphate and the pathways of precipitate formation are discussed. The optimal total phosphate concentration is found to be of 0.15 M. However, the induction time is assumed to be dependent not only on the total phosphate concentrations, but also on the ratio of total vanadium(V) to sulphate concentrations.

Influence of high-conductivity buffer composition on field-enhanced sample injection coupled to sweeping in CE.

PubMed

Anres, Philippe; Delaunay, Nathalie; Vial, Jérôme; Thormann, Wolfgang; Gareil, Pierre

2013-02-01

The aim of this work was to clarify the mechanism taking place in field-enhanced sample injection coupled to sweeping and micellar EKC (FESI-Sweep-MEKC), with the utilization of two acidic high-conductivity buffers (HCBs), phosphoric acid or sodium phosphate buffer, in view of maximizing sensitivity enhancements. Using cationic model compounds in acidic media, a chemometric approach and simulations with SIMUL5 were implemented. Experimental design first enabled to identify the significant factors and their potential interactions. Simulation demonstrates the formation of moving boundaries during sample injection, which originate at the initial sample/HCB and HCB/buffer discontinuities and gradually change the compositions of HCB and BGE. With sodium phosphate buffer, the HCB conductivity increased during the injection, leading to a more efficient preconcentration by staking (about 1.6 times) than with phosphoric acid alone, for which conductivity decreased during injection. For the same injection time at constant voltage, however, a lower amount of analytes was injected with sodium phosphate buffer than with phosphoric acid. Consequently sensitivity enhancements were lower for the whole FESI-Sweep-MEKC process. This is why, in order to maximize sensitivity enhancements, it is proposed to work with sodium phosphate buffer as HCB and to use constant current during sample injection. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effects of nitrogen and phosphorous stress on the formation of high value LC-PUFAs in Porphyridium cruentum.

PubMed

Hu, Hao; Wang, Hou-Feng; Ma, Lin-Lin; Shen, Xiao-Fei; Zeng, Raymond Jianxiong

2018-04-18

This study systematically examined the effect of nitrogen and phosphorous stress on the formation of linoleic acid (LA), arachidonic acid (ARA), and eicosapentaenoic acid (EPA) in Porphyridium cruentum gy-h56. P. cruentum was cultivated in six different media conferring different conditions of nitrogen (N) sufficiency/deprivation and phosphorous (P) sufficiency/limitation/deprivation. Over a 16-day cultivation process, the dry-weight content, proportion of total fatty acids (TFAs), and the concentration in the medium of linoleic acid (LA) were greatly improved by a maximum of 2.5-, 1.6-, and 1.1-fold, respectively, under conditions of N or P deprivation compared with N and P sufficiency. In contrast, levels of EPA or ARA were not enhanced under N or P stress conditions. Additionally, the results showed that N deprivation weakened the impact of P deficiency on the content and proportions of LA and EPA, while P deprivation enhanced the impact of N starvation on the content and proportions of LA and EPA. The conditions of N sufficiency and P deprivation (N+P-) were the optimal conditions for the production of LA, while the optimal conditions for EPA, ARA, and TFAs production were N sufficiency and P limitation (N+P-lim). This study suggests the potential application of combining N removal from saline wastewater with the production of LA, ARA, EPA, and biodiesel.

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.

Nanoporous carbon materials with enhanced supercapacitance performance and non-aromatic chemical sensing with C1/C2 alcohol discrimination

NASA Astrophysics Data System (ADS)

Shrestha, Lok Kumar; Adhikari, Laxmi; Shrestha, Rekha Goswami; Adhikari, Mandira Pradhananga; Adhikari, Rina; Hill, Jonathan P.; Pradhananga, Raja Ram; Ariga, Katsuhiko

2016-01-01

We have investigated the textural properties, electrochemical supercapacitances and vapor sensing performances of bamboo-derived nanoporous carbon materials (NCM). Bamboo, an abundant natural biomaterial, was chemically activated with phosphoric acid at 400 °C and the effect of impregnation ratio of phosphoric acid on the textural properties and electrochemical performances was systematically investigated. Fourier transform-infrared (FTIR) spectroscopy confirmed the presence of various oxygen-containing surface functional groups (i.e. carboxyl, carboxylate, carbonyl and phenolic groups) in NCM. The prepared NCM are amorphous in nature and contain hierarchical micropores and mesopores. Surface areas and pore volumes were found in the range 218-1431 m2 g-1 and 0.26-1.26 cm3 g-1, respectively, and could be controlled by adjusting the impregnation ratio of phosphoric acid and bamboo cane powder. NCM exhibited electrical double-layer supercapacitor behavior giving a high specific capacitance of c.256 F g-1 at a scan rate of 5 mV s-1 together with high cyclic stability with capacitance retention of about 92.6% after 1000 cycles. Furthermore, NCM exhibited excellent vapor sensing performance with high sensitivity for non-aromatic chemicals such as acetic acid. The system would be useful to discriminate C1 and C2 alcohol (methanol and ethanol).

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. © The Author(s) 2016.

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

Cho, Young-Sik; Huh, Young-Duk, E-mail: ydhuh@dankook.ac.kr

Highlights: • Red-emitting BaWO{sub 4}:Eu phosphors were prepared in hexane-water bilayer system. • The hydrophobic nanometer-sized BaWO{sub 4}:Eu phosphors were obtained in hexane. • The hydrophilic micrometer-sized BaWO{sub 4}:Eu dendrites were obtained in water. - Abstract: BaWO{sub 4}:Eu phosphors were prepared by performing a solvothermal reaction in a water–hexane bilayer system. A barium oleate (and europium oleate) complex was obtained in hexane via a phase transfer reaction involving Ba{sup 2+} (and Eu{sup 3+}) ions in an aqueous solution of sodium oleate. The outer surfaces of the nanometer-sized BaWO{sub 4}:Eu phosphors were capped by the long alkyl chain of oleate; therefore,more » the hydrophobic nanometer-sized BaWO{sub 4}:Eu phosphors preferentially dissolved in the hexane layer. The micrometer-sized BaWO{sub 4}:Eu phosphors were obtained in the water layer. The BaWO{sub 4}:Eu phosphors prepared in hexane and water yielded sharp strong absorption and emission peaks at 464 and 615 nm, respectively, due to the {sup 7}F{sub 0} → {sup 5}D{sub 2} and the {sup 5}D{sub 0} →{sup 7} F{sub 2} transitions of the Eu{sup 3+} ions. The BaWO{sub 4}:Eu phosphors are good candidate red-emitting phosphors for use in InGaN blue-emitting diodes, which have an emission wavelength of 465 nm.« less

Light propagation in phosphor-filled matrices for photovoltaic PL down-shifting

NASA Astrophysics Data System (ADS)

Solodovnyk, Anastasiia; Lipovšek, Benjamin; Forberich, Karen; Stern, Edda; Batentschuk, Miroslaw; Topič, Marko; Brabec, Christoph J.

2014-09-01

Efficient transparent light converters have received lately a growing interest from optical device industries (LEDs, PV, etc.). While organic luminescent dyes were tested in PV light-converting application, such restrictions as small Stokes shifts, short lifetimes, and relatively high costs must yet be overcome. Alternatively, use of phosphors in transparent matrix materials would mean a major breakthrough for this technology, as phosphors exhibit long-term stability and are widely available. For the fabrication of phosphor-filled layers tailored specifically for the desired application, it is of great importance to gain deep understanding of light propagation through the layers, including the detailed optical interplay between the phosphor particles and the matrix material. Our measurements show that absorption and luminescent behavior of the phosphors and especially the scattering of light by the phosphor particles play an important role. In this contribution we have investigated refractive index difference between transparent binder and phosphors. Commercially available highly luminescent UV and near-UV absorbing μm-sized powder is chosen for the fabrication of phosphor-filled layers with varied refractive index of transparent polymer matrix, and well-defined particle size distributions. Solution-processed thick layers on glass substrates are optically analyzed and compared with simulation results acquired from CROWM, a combined wave optics/ray optics home-built software. The results demonstrate the inter-dependence of the layer parameters, prove the importance of careful optimization steps required for fabrication of efficient light converting layers, and, thus, show a path into the future of this promising approach.

Plasma impregnation of wood with fire retardants

NASA Astrophysics Data System (ADS)

Pabeliña, Karel G.; Lumban, Carmencita O.; Ramos, Henry J.

2012-02-01

The efficacy of chemical and plasma treatments with phosphate and boric compounds, and nitrogen as flame retardants on wood are compared in this study. The chemical treatment involved the conventional method of spraying the solution over the wood surface at atmospheric condition and chemical vapor deposition in a vacuum chamber. The plasma treatment utilized a dielectric barrier discharge ionizing and decomposing the flame retardants into innocuous simple compounds. Wood samples are immersed in either phosphoric acid, boric acid, hydrogen or nitrogen plasmas or a plasma admixture of two or three compounds at various concentrations and impregnated by the ionized chemical reactants. Chemical changes on the wood samples were analyzed by Fourier transform infrared spectroscopy (FTIR) while the thermal changes through thermo gravimetric analysis (TGA). Plasma-treated samples exhibit superior thermal stability and fire retardant properties in terms of highest onset temperature, temperature of maximum pyrolysis, highest residual char percentage and comparably low total percentage weight loss.

Phenytoin crystal growth rates in the presence of phosphate and chloride ions

NASA Astrophysics Data System (ADS)

Zipp, G. L.; Rodríguez-Hornedo, N.

1992-09-01

Phenytoin crystal growth kinetics have been measured as a function of supersaturation in pH 2.2 phosphoric acid and pH 2.2 hydrochloric acid solutions. Two different methods were used for the kinetic analysis. The first involved a zone-sensing device which provided an analysis of the distribution of crystals in a batch crystallizer. Crystal growth rates were calculated from the increase in the size of the distribution with time. In the second method, growth rates were evaluated from the change in size with time of individual crystals observed under an inverted microscope. The results from each method compare favorably. The use of both techniques provides an excellent opportunity to exploit the strengths of each: an average growth rate from a population of crystals from batch crystallization and insight into the effect of growth on the morphology of the crystals from the individual crystal measurements.

Long-term stability assessment of AlGaN/GaN field effect transistors modified with peptides: Device characteristics vs. surface properties

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

Rohrbaugh, Nathaniel; Bryan, Isaac; Bryan, Zachary

AlGaN/GaN Field Effect Transistors (FETs) are promising biosensing devices. Functionalization of these devices is explored in this study using an in situ approach with phosphoric acid etchant and a phosphonic acid derivative. Devices are terminated on peptides and soaked in water for up to 168 hrs to examine FETs for both device responses and surface chemistry changes. Measurements demonstrated threshold voltage shifting after the functionalization and soaking processes, but demonstrated stable FET behavior throughout. X-ray photoelectron spectroscopy and atomic force microscopy confirmed peptides attachment to device surfaces before and after water soaking. Results of this work point to the stabilitymore » of peptide coated functionalized AlGaN/GaN devices in solution and support further research of these devices as disposable, long term, in situ biosensors.« less

A kinetic study of Trichoderma reesei Cel7B catalyzed cellulose hydrolysis.

PubMed

Song, Xiangfei; Zhang, Shujun; Wang, Yefei; Li, Jingwen; He, Chunyan; Yao, Lishan

2016-06-01

One prominent feature of Trichoderma reesei (Tr) endoglucanases catalyzed cellulose hydrolysis is that the reaction slows down quickly after it starts (within minutes). But the mechanism of the slowdown is not well understood. A structural model of Tr- Cel7B catalytic domain bound to cellulose was built computationally and the potentially important binding residues were identified and tested experimentally. The 13 tested mutants show different binding properties in the adsorption to phosphoric acid swollen cellulose and filter paper. Though the partitioning parameter to filter paper is about 10 times smaller than that to phosphoric acid swollen cellulose, a positive correlation is shown for two substrates. The kinetic studies show that the reactions slow down quickly for both substrates. This slowdown is not correlated to the binding constant but anticorrelated to the enzyme initial activity. The amount of reducing sugars released after 24h by Cel7B in phosphoric acid swollen cellulose, Avicel and filter paper cellulose hydrolysis is correlated with the enzyme activity against a soluble substrate p-nitrophenyl lactoside. Six of the 13 tested mutants, including N47A, N52D, S99A, N323D, S324A, and S346A, yield ∼15-35% more reducing sugars than the wild type (WT) Cel7B in phosphoric acid swollen cellulose and filter paper hydrolysis. This study reveals that the slowdown of the reaction is not due to the binding of the enzyme to cellulose. The activity of Tr- Cel7B against the insoluble substrate cellulose is determined by the enzyme's capability in hydrolyzing the soluble substrate. Copyright © 2016 Elsevier Inc. All rights reserved.

Improving phosphorus uptake and wheat productivity by phosphoric acid application in alkaline calcareous soils.

PubMed

Akhtar, Muhammad; Yaqub, Muhammad; Naeem, Asif; Ashraf, Muhammad; Hernandez, Vicente Espinosa

2016-08-01

Low phosphorus (P) efficiency from existing granular fertilisers necessitates searching for efficient alternatives to improve wheat productivity in calcareous soil. Multi-location trials have shown that phosphoric acid (PA) produced 16% higher wheat grain over commercial P fertilisers, i.e. diammonium phosphate (DAP) and triple superphosphate (TSP). Methods of P application significantly influenced grain yield and the efficiency of methods was observed in the order: PA placement below seed > PA, DAP or TSP fertigation > DAP or TSP broadcast. The sub-surface application of PA produced highest grain yields (mean of all rates), i.e. 4669, 4158 and 3910 kg ha(-1) in Bagh, Bhalwal and Shahpur soil series, respectively. Phosphoric acid at 66 kg P2 O5 ha(-1) was found more effective in increasing gain yield over that of control. Trend in grain P uptake was found similar to that observed for grain yield. Maximum P uptake by grain was recorded at the highest P rate and the lowest at zero P. The significant increase in P uptake with P rates was generally related to the increase in yield rather than its concentration in grain. Phosphorus agronomic efficiency (PAE) and phosphorus recovery efficiency (PRE) were found higher at lower P rate (44 kg P2 O5 ha(-1) ) and decreased with P application. However, PA applied by the either method resulted in higher PAE and PRE compared to DAP and TSP. Phosphoric acid is suggested as an efficient alternative to commercial granular P fertilisers for wheat production in alkaline calcareous soils. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

46 CFR 153.1011 - Changing containment systems and hoses to and from alkylene oxide service.

Code of Federal Regulations, 2012 CFR

2012-10-01

... reactive with alkylene oxides: (1) Non-oxidizing mineral acids (e.g. hydrochloric, phosphoric); (2) Sulfuric acid; (3) Nitric acid; (4) Organic acids (e.g. acetic, formic); (5) Halogenated organic acids (e.g... condition with no heavy rust accumulations or traces of previous cargoes; (2) No alkylene oxide is loaded...

46 CFR 153.1011 - Changing containment systems and hoses to and from alkylene oxide service.

Code of Federal Regulations, 2011 CFR

2011-10-01

... reactive with alkylene oxides: (1) Non-oxidizing mineral acids (e.g. hydrochloric, phosphoric); (2) Sulfuric acid; (3) Nitric acid; (4) Organic acids (e.g. acetic, formic); (5) Halogenated organic acids (e.g... condition with no heavy rust accumulations or traces of previous cargoes; (2) No alkylene oxide is loaded...

46 CFR 153.1011 - Changing containment systems and hoses to and from alkylene oxide service.

Code of Federal Regulations, 2014 CFR

2014-10-01

... reactive with alkylene oxides: (1) Non-oxidizing mineral acids (e.g. hydrochloric, phosphoric); (2) Sulfuric acid; (3) Nitric acid; (4) Organic acids (e.g. acetic, formic); (5) Halogenated organic acids (e.g... condition with no heavy rust accumulations or traces of previous cargoes; (2) No alkylene oxide is loaded...

46 CFR 153.1011 - Changing containment systems and hoses to and from alkylene oxide service.

Code of Federal Regulations, 2010 CFR

2010-10-01

... reactive with alkylene oxides: (1) Non-oxidizing mineral acids (e.g. hydrochloric, phosphoric); (2) Sulfuric acid; (3) Nitric acid; (4) Organic acids (e.g. acetic, formic); (5) Halogenated organic acids (e.g... condition with no heavy rust accumulations or traces of previous cargoes; (2) No alkylene oxide is loaded...

46 CFR 153.1011 - Changing containment systems and hoses to and from alkylene oxide service.

Code of Federal Regulations, 2013 CFR

2013-10-01

... reactive with alkylene oxides: (1) Non-oxidizing mineral acids (e.g. hydrochloric, phosphoric); (2) Sulfuric acid; (3) Nitric acid; (4) Organic acids (e.g. acetic, formic); (5) Halogenated organic acids (e.g... condition with no heavy rust accumulations or traces of previous cargoes; (2) No alkylene oxide is loaded...

Superhard Transparent Coatings

DTIC Science & Technology

1975-04-01

alcohol has OH groups and polymethacrylic acid has carboxyl COOH groups. These form a clear suspension with the sub- micron hydrophilic particles...PHOSPHORIC ACID /SILICA/PVA 38 SYSTEM 3: ALON/POLYSILICIC ACID /BORACIC ACID 38 SYSTEM 4: ALON/SILICA/CYMEL - MOH HARDNESS VS...60 POLYSILICIC ACID 60 Methods for the Preparation of a Polystllcate/ Alon Suspension 61 Compositions 62 STRETCHED PLEX 63 OPTIMUM COMPOSITIONS

A new 68Ge/68Ga generator system using an organic polymer containing N-methylglucamine groups as adsorbent for 68Ge.

PubMed

Nakayama, M; Haratake, M; Ono, M; Koiso, T; Harada, K; Nakayama, H; Yahara, S; Ohmomo, Y; Arano, Y

2003-01-01

A macroporous styrene-divinylbenzene copolymer containing N-methylglucamine groups was selected for a new 68Ge/68Ga generator system. This resin packed into a column effectively adsorbed the parent nuclide 68Ge. The daughter 68Ga was eluted from the resin with a solution of a low-affinity gallium chelating ligand such as citric or phosphoric acid. The 68Ge leakage was less than 0.0004% of the 68Ge adsorbed on the resin. By simple mixing of transferrin and desferoxamine conjugated HSA and IgG with the eluate from the column, 68Ga-labeling was completed in high yield. Copyright 2002 Elsevier Science Ltd.

Preparation of titanium phosphates with additives in hydrothermal process and their powder properties for cosmetics.

PubMed

Onoda, Hiroaki; Yamaguchi, Taisuke

2013-04-01

In this study, titanium phosphates were prepared from titanium chloride and phosphoric acid, sodium pyrophosphate and sodium triphosphate solutions with water retention compounds in hydrothermal process as a novel white pigment for cosmetics. Their chemical composition, powder properties, photo catalytic activity, water retention and smoothness were studied. The addition of glycerin in the preparation from sodium pyrophosphate has the useful method to obtain homogenized spherical particles of titanium phosphate pigments for the cosmetics. These titanium phosphates had less photo catalytic activity to protect the sebum on the skin. © 2012 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

Rapid microwave-assisted acid extraction of metals from chromated copper arsenate (CCA)-treated southern pine wood

Treesearch

Bin Yu; Chung Y. Hse; Todd F. Shupe

2009-01-01

The effects of acid concentration, reaction time, and temperature in a microwave reactor on recovery of CCA-treated wood were evaluated. Extraction of copper, chromium, and arsenic metals from chromated copper arsenate (CCA)-treated southern pine wood samples with three different acids (i.e., acetic acid, oxalic acid, and phosphoric acid) was investigated using in...

21 CFR 172.841 - Polydextrose.

Code of Federal Regulations, 2013 CFR

2013-04-01

... consists either of approximately 89 percent D-glucose, 10 percent sorbitol, and 1 percent citric acid or of approximately 90 percent D-glucose, 10 percent sorbitol, and 0.1 percent phosphoric acid, on a weight basis. (2...

7 CFR 58.305 - Meaning of words.

Code of Federal Regulations, 2014 CFR

2014-01-01

... thiodipropionate 0.02% of fat. Antioxidant synergists Citric acid Limit by GMP. Sodium citrate Limit by GMP. Isopropyl citrate 0.02% of food. Phosphoric acid Limit by GMP. Monoglyceride citrate 200 ppm of fat. An...

21 CFR 172.841 - Polydextrose.

Code of Federal Regulations, 2011 CFR

2011-04-01

... consists either of approximately 89 percent D-glucose, 10 percent sorbitol, and 1 percent citric acid or of approximately 90 percent D-glucose, 10 percent sorbitol, and 0.1 percent phosphoric acid, on a weight basis. (2...

21 CFR 172.841 - Polydextrose.

Code of Federal Regulations, 2012 CFR

2012-04-01

... consists either of approximately 89 percent D-glucose, 10 percent sorbitol, and 1 percent citric acid or of approximately 90 percent D-glucose, 10 percent sorbitol, and 0.1 percent phosphoric acid, on a weight basis. (2...

7 CFR 58.305 - Meaning of words.

Code of Federal Regulations, 2013 CFR

2013-01-01

... thiodipropionate 0.02% of fat. Antioxidant synergists Citric acid Limit by GMP. Sodium citrate Limit by GMP. Isopropyl citrate 0.02% of food. Phosphoric acid Limit by GMP. Monoglyceride citrate 200 ppm of fat. An...

7 CFR 58.305 - Meaning of words.

Code of Federal Regulations, 2012 CFR

2012-01-01

... thiodipropionate 0.02% of fat. Antioxidant synergists Citric acid Limit by GMP. Sodium citrate Limit by GMP. Isopropyl citrate 0.02% of food. Phosphoric acid Limit by GMP. Monoglyceride citrate 200 ppm of fat. An...

21 CFR 172.841 - Polydextrose.

Code of Federal Regulations, 2010 CFR

2010-04-01

... consists either of approximately 89 percent D-glucose, 10 percent sorbitol, and 1 percent citric acid or of approximately 90 percent D-glucose, 10 percent sorbitol, and 0.1 percent phosphoric acid, on a weight basis. (2...

Phosphate Fertilizer Industry: New Source Performance Standards - 40 CFR 60 Subparts T, U, V, W & X

EPA Pesticide Factsheets

Learn about the the NSPS regulations for Diammonium phosphate plants, superphosphoric acid plants, granular triple superphosphate storage facilities, triple superphosphate plants & wet-process phosphoric acid plants

21 CFR 133.169 - Pasteurized process cheese.

Code of Federal Regulations, 2012 CFR

2012-04-01

... of the following: A vinegar, lactic acid, citric acid, acetic acid, and phosphoric acid, in such... paragraph (d) of this section may be used. (2) During its preparation, pasteurized process cheese is heated... determined by the methods prescribed in § 133.5(a), (b), and (d). (6) The weight of each variety of cheese in...

21 CFR 133.169 - Pasteurized process cheese.

Code of Federal Regulations, 2013 CFR

2013-04-01

... of the following: A vinegar, lactic acid, citric acid, acetic acid, and phosphoric acid, in such... paragraph (d) of this section may be used. (2) During its preparation, pasteurized process cheese is heated... determined by the methods prescribed in § 133.5(a), (b), and (d). (6) The weight of each variety of cheese in...

21 CFR 133.169 - Pasteurized process cheese.

Code of Federal Regulations, 2014 CFR

2014-04-01

... of the following: A vinegar, lactic acid, citric acid, acetic acid, and phosphoric acid, in such... paragraph (d) of this section may be used. (2) During its preparation, pasteurized process cheese is heated... determined by the methods prescribed in § 133.5(a), (b), and (d). (6) The weight of each variety of cheese in...

Gearing.

DTIC Science & Technology

1985-12-01

trichloroethyl phosphite and a phosphate ester containing a pentachlorphenyl radical. Most of the Asperity heights phosphorous compounds in gear oils...108) found that phosphorous compounds chemisorption. These boundary films can be thinner than ( 1 0 u ts n 0.025 pm (I in ) or several microinches thick...Pinion 1 .. dibutylxanthic acid disulfide. Ŗ %- Lead soaps have been used in lubricants for many 02 years. They resist the wiping and sliding action in

Solvent Extraction of Rare Earth Elements from a Nitric Acid Leach Solution of Apatite by Mixtures of Tributyl Phosphate and Di-(2-ethylhexyl) Phosphoric Acid

NASA Astrophysics Data System (ADS)

Ferdowsi, Ali; Yoozbashizadeh, Hossein

2017-12-01

Solvent extraction of rare earths from nitrate leach liquor of apatite using mixtures of tributyl phosphate (TBP) and di-(2-ethylhexyl) phosphoric acid (D2EHPA) was studied. The effects of nitrate and hydrogen ion concentration of the aqueous phase as well as the composition and concentration of extractants in the organic phase on the extraction behavior of lanthanum, cerium, neodymium, and yttrium were investigated. The distribution ratio of REEs increases by increasing the nitrate concentration in aqueous phase and concentration of extractants in organic phase, but the hydrogen ion concentration in aqueous phase has a decreasing effect. Yttrium as a heavy rare earth is more sensitive to these parameters than light rare earth elements. Although the composition of organic phase has a minor effect on the extraction of light rare earths, the percent of extraction of yttrium decreases dramatically by increasing the TBP content of organic phase. Mixtures of TBP and D2EHPA can show either synergism or antagonism extraction depending on the concentration and composition of extractants in organic phase. The best condition for separating rare earth elements in groups of heavy and light REEs can be achieved at high nitrate concentration, low H+ concentration, and high concentration of D2EHPA in organic phase. Separation of Ce and La by TBP and D2EHPA is practically impossible in the studied conditions; however, low nitrate concentration and high hydrogen ion concentration in aqueous phase and low concentration of extractants in organic phase favor the separation of Nd from other light rare earth elements.

Polymer Based Thin Film Screen Preparation Technique

NASA Astrophysics Data System (ADS)

Valais, I.; Michail, C.; Fountzoula, C.; Fountos, G.; Saatsakis, G.; Karabotsos, A.; Panayiotakis, G. S.; Kandarakis, I.

2017-11-01

Phosphor screens, mainly prepared by electrophoresis, demonstrate brightness equal to the standard sedimentation on glass or quartz substrate process and are capable of very high resolution. Nevertheless, they are very fragile, the shape of the screen is limited to the substrate shape and in order to achieve adequate surface density for application in medical imaging, a significant quantity of the phosphor will be lost. Fluorescent films prepared by the dispersion of phosphor particles into a polymer matrix could solve the above disadvantages. The aim of this study is to enhance the stability of phosphor screens via the incorporation of phosphor particles into a PMMA (PolyMethyl MethAcrylate) matrix. PMMA is widely used as a plastic optical fiber, it shows almost nearly no dispersion effects and it is transparent in the whole visible spectral range. Different concentrations of PMMA in MMA (Methyl Methacrylate) were examined and a 37.5 % w/w solution was used for the preparation of the thin polymer film, since optical quality characteristics were found to depend on PMMA in MMA concentration. Scanning Electron Microscopy (SEM) images of the polymer screens demonstrated high packing density and uniform distribution of the phosphor particles. This method could be potentially used for phosphor screen preparation of any size and shape.

Antioxidative Peptides Derived from Enzyme Hydrolysis of Bone Collagen after Microwave Assisted Acid Pre-Treatment and Nitrogen Protection

PubMed Central

Lin, Yun-Jian; Le, Guo-Wei; Wang, Jie-Yun; Li, Ya-Xin; Shi, Yong-Hui; Sun, Jin

2010-01-01

This study focused on the preparation method of antioxidant peptides by enzymatic hydrolysis of bone collagen after microwave assisted acid pre-treatment and nitrogen protection. Phosphoric acid showed the highest ability of hydrolysis among the four other acids tested (hydrochloric acid, sulfuric acid and/or citric acid). The highest degree of hydrolysis (DH) was 9.5% using 4 mol/L phosphoric acid with a ratio of 1:6 under a microwave intensity of 510 W for 240 s. Neutral proteinase gave higher DH among the four protease tested (Acid protease, neutral protease, Alcalase and papain), with an optimum condition of: (1) ratio of enzyme and substrate, 4760 U/g; (2) concentration of substrate, 4%; (3) reaction temperature, 55 °C and (4) pH 7.0. At 4 h, DH increased significantly (P < 0.01) under nitrogen protection compared with normal microwave assisted acid pre-treatment hydrolysis conditions. The antioxidant ability of the hydrolysate increased and reached its maximum value at 3 h; however DH decreased dramatically after 3 h. Microwave assisted acid pre-treatment and nitrogen protection could be a quick preparatory method for hydrolyzing bone collagen. PMID:21151439

A study on chloride induced depassivation of Fe-P-C-Si and Fe-P-C-Si-N steels in simulated concrete pore solution

NASA Astrophysics Data System (ADS)

Mehta, Yashwant; Chaudhari, Gajanan P.; Dabhade, Vikram V.

2018-03-01

The corrosion behaviour of high phosphorous steels containing varying amounts of silicon and nitrogen was studied by potentiodynamic polarization, linear polarization resistance (LPR) and electrochemical impedance spectroscopy (EIS) measurements. The morphology of a steel specimen tested in chloride containing concrete pore solution was studied using scanning electron microscope (SEM) and the elemental distribution at the pitting corrosion area was investigated using electron dispersive spectroscopy (EDS). The results showed that the capacitance increased and resistance declined with immersion time in Ca(OH)2 solution containing 0.1% chloride for plain carbon steel. The opposite was observed in the case of the high phosphorous steels. The potentiodynamic polarization and LPR results complement the EIS findings. Corrosion behaviour could be described with an equivalent circuit having two time constants. The creation, expansion and degradation of the passive layer were discussed with the help of the equivalent circuit elements. The SEM-EDS studies revealed that MnS inclusions at the surface could have a role in the initiation and growth of pits and that phosphorous was present at the pit free surface of the steel.

Electrodeposition of High Quality Nickel Phosphorous Alloys for Pollution Reduction and Energy Conservation

NASA Technical Reports Server (NTRS)

Engelhaupt, Darell; Ramsey, Brian

2003-01-01

NASA and the University of Alabama in Huntsville have developed ecologically friendly, versatile nickel and nickel cobalt phosphorous electroplating processes. Solutions show excellent performance with high efficiency for vastly extended throughput. Properties include, clean, low temperature operation (40 - 60 C), high Faradaic efficiency, low stress and high hardness. A variety of alloy and plating speed options are easily achieved from the same chemistry using soluble anodes for metal replacement with only 25% of the phosphorous additions required for electroless nickel. Thick deposits are easily achieved unattended, for electroforming freestanding shapes without buildup of excess orthophosphate or stripping of equipment.

Electrodeposition of High Quality Nickel Phosphorous Alloys for Pollution Reduction and Energy Conservation

NASA Technical Reports Server (NTRS)

Engelhaupt, Darell; Ramsey, Brian

2004-01-01

NASA and the University of Alabama in Huntsville have developed ecologically friendly, versatile nickel and nickel cobalt phosphorous electroplating processes. Solutions show excellent performance with high efficiency for vastly extended throughput. Properties include, clean, low temperature operation (40 - 60 C), high Faradaic efficiency, low stress and high hardness. A variety of alloy and plating speed options are easily achieved from the same chemistry using soluble anodes for metal replacement with only 25% of the phosphorous additions required for electroless nickel. Thick deposits are easily achieved unattended, for electroforming freestanding shapes without buildup of excess orthophosphate or stripping of equipment.

Strong green fluorescent hydrogels with Ba2 MgSi2 O7 :Eu2+ phosphor embedded in cellulose.

PubMed

Zhang, Xinguo; Qin, Xingzhen; Chen, Hailan

2017-06-01

Non-cytotoxic and green-emitting fluorescent hydrogels were constructed from a cellulose solution containing Ba 2 MgSi 2 O 7 :Eu 2 + green phosphor in a NaOH/urea aqueous system. The structure, optical properties and cytotoxicity of these hydrogels were studied. The Ba 2 MgSi 2 O 7 :Eu 2 + phosphor particles were dispersed evenly in the cellulose hydrogel matrix. Good luminescent properties of Ba 2 MgSi 2 O 7 :Eu 2 + phosphor were maintained in the hydrogels, leading to strong green emission under ultraviolet excitation. Fluorescent hydrogels have no obvious cytotoxicity in a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) proliferation test, and have potential use in in vivo applications like optical imaging and drug delivery. Copyright © 2016 John Wiley & Sons, Ltd.

Photoluminescence emission of nanoporous anodic aluminum oxide films prepared in phosphoric acid

PubMed Central

2012-01-01

The photoluminescence emission of nanoporous anodic aluminum oxide films formed in phosphoric acid is studied in order to explore their defect-based subband electronic structure. Different excitation wavelengths are used to identify most of the details of the subband states. The films are produced under different anodizing conditions to optimize their emission in the visible range. Scanning electron microscopy investigations confirm pore formation in the produced layers. Gaussian analysis of the emission data indicates that subband states change with anodizing parameters, and various point defects can be formed both in the bulk and on the surface of these nanoporous layers during anodizing. PMID:23272786

Testing of Candidate Polymeric Materials for Compatibility with Pure Alternate Pretreat as Part of the Universal Waste Management System (UWMS)

NASA Technical Reports Server (NTRS)

Wingard, C. D.

2018-01-01

The Universal Waste Management System (UWMS) is an improved Waste Collection System for astronauts living and working in low Earth orbit spacecraft. Polymeric materials used in water recovery on International Space Station are regularly exposed to phosphoric acid-treated 'pretreated' urine. Polymeric materials used in UWMS are not only exposed to pretreated urine, but also to concentrated phosphoric acid with oxidizer before dilution known as 'pure pretreat.' Samples of five different polymeric materials immersed in pure pretreat for 1 year were tested for liquid compatibility by measuring changes in storage modulus with a dynamic mechanical analyzer.

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.

Enhanced electrochemical properties of SnO2-graphene-carbon nanofibers tuned by phosphoric acid for potassium storage.

PubMed

Huang, Zhao; Chen, Zhi; Ding, Shuangshuang; Chen, Changmiao; Zhang, Ming

2018-06-21

Potassium-ion batteries (KIBs) are considered as attractive alternatives to commercial lithium-ion batteries (LIBs). However, the lack of suitable electrodes to host large K+ for rapid as well as reversible insertion/extraction hinders the developments of KIBs. As an attempt, the phosphoric acid doped SnO2-graphene-carbon (P-SGC) nanofibers synthesized with a facile electrospinning method are introduced and applied as anode materials for KIBs. The P-SGC anodes present a reversible capacity of 285.9 mAh g-1 over 60 cycles at the current density of 100 mA g-1, and the high rate capacity of 208.53 mAh g-1 at 1 A g-1 as well. Emphasis is placed on enhancing the electrochemical properties of the SGC nanofibers by phosphoric acid modification through more active sites and higher electrical conductivity, accounting for improved K+ diffusion kinetics. Meanwhile, the coated carbon matrix and dispersive graphene buffer the structural changes and protect the active materials from destruction, leading to the good structural stability. With the presented results, these P-SGC nanofibers show attractive potential for future energy storage application of KIBs. © 2018 IOP Publishing Ltd.

Influence of enamel surface preparation on composite bond strength.

PubMed

Matos, Adriana Bona; Tate, William H; Powers, John M

2003-09-01

To evaluate the influence of air-particle abrasion and treatments on in vitro tensile bond strength of resin composite bonded to human enamel was evaluated using a single-bottle adhesive. Human teeth were divided into 12 groups of three treatments (none, 27-microm Al2O3 air-particle abrasion, 50-microm Al2O3 air-particle abrasion) and four conditioners [none, phosphoric acid (PA), NRC (no-rinse conditioner), and PA/NRC]. Bonding agent (Prime & Bond NT) and a resin composite (TPH Spectrum) were applied as inverted cones. Specimens were stored for 24 hours at 37 degrees C and debonded in tension using a testing machine at 0.5 mm/minute. Phosphoric acid treatment used with Prime & Bond NT produced the best bond strengths (24 MPa) to enamel for surfaces treated with 27-microm air-particle abrasion and for surfaces not treated with air-particle abrasion (control). With one exception, air-particle abraded surfaces resulted in bond strengths between 9 to 16 MPa. NRC with or without the use of phosphoric acid in general did not improve tensile bond strength to enamel when compared to surfaces not treated with NRC.

Novel Development of Phosphate Treated Porous Hydroxyapatite.

PubMed

Doi, Kazuya; Abe, Yasuhiko; Kobatake, Reiko; Okazaki, Yohei; Oki, Yoshifumi; Naito, Yoshihito; Prananingrum, Widyasri; Tsuga, Kazuhiro

2017-12-08

Phosphoric acid-etching treatment to the hydroxyapatite (HA) surface can modify the solubility calcium structure. The aim of the present study was to develop phosphate treated porous HA, and the characteristic structures and stimulation abilities of bone formation were evaluated to determine its suitability as a new type of bone graft material. Although the phosphoric acid-etching treatment did not alter the three-dimensional structure, a micrometer-scale rough surface topography was created on the porous HA surface. Compared to porous HA, the porosity of phosphate treated porous HA was slightly higher and the mechanical strength was lower. Two weeks after placement of the cylindrical porous or phosphate treated porous HA in a rabbit femur, newly formed bone was detected in both groups. At the central portion of the bone defect area, substantial bone formation was detected in the phosphate treated porous HA group, with a significantly higher bone formation ratio than detected in the porous HA group. These results indicate that phosphate treated porous HA has a superior surface topography and bone formation abilities in vivo owing to the capacity for both osteoconduction and stimulation abilities of bone formation conferred by phosphoric acid etching.

Novel Development of Phosphate Treated Porous Hydroxyapatite

PubMed Central

Doi, Kazuya; Abe, Yasuhiko; Kobatake, Reiko; Okazaki, Yohei; Oki, Yoshifumi; Naito, Yoshihito; Prananingrum, Widyasri; Tsuga, Kazuhiro

2017-01-01

Phosphoric acid-etching treatment to the hydroxyapatite (HA) surface can modify the solubility calcium structure. The aim of the present study was to develop phosphate treated porous HA, and the characteristic structures and stimulation abilities of bone formation were evaluated to determine its suitability as a new type of bone graft material. Although the phosphoric acid-etching treatment did not alter the three-dimensional structure, a micrometer-scale rough surface topography was created on the porous HA surface. Compared to porous HA, the porosity of phosphate treated porous HA was slightly higher and the mechanical strength was lower. Two weeks after placement of the cylindrical porous or phosphate treated porous HA in a rabbit femur, newly formed bone was detected in both groups. At the central portion of the bone defect area, substantial bone formation was detected in the phosphate treated porous HA group, with a significantly higher bone formation ratio than detected in the porous HA group. These results indicate that phosphate treated porous HA has a superior surface topography and bone formation abilities in vivo owing to the capacity for both osteoconduction and stimulation abilities of bone formation conferred by phosphoric acid etching. PMID:29292788

Effect of phosphoric acid pretreatment of corncobs on the fermentability of Clostridium beijerinckii TISTR 1461 for biobutanol production.

PubMed

Boonsombuti, Akarin; Luengnaruemitchai, Apanee; Wongkasemjit, Sujitra

2015-01-01

Corncobs pretreated with H2SO4, HNO3, and H3PO4 were compared to evaluate the fermentation ability of Clostridium beijerinckii TISTR 1461 to produce biobutanol via acetone-butanol-ethanol (ABE) fermentation. It was found that the hydrolysate from H3PO4 pretreatment could be used as a substrate without any inhibitor removal methods. However, in terms of sugar yield, it gave the lowest total sugars in both pretreatment and enzymatic hydrolysis. Response surface methodology was applied to optimize enzymatic hydrolysis of the pretreated corncobs. The optimized conditions reduced the consumption of enzymes and hydrolysis time to 7.68 FPU/g biomass and 63.88 hr, respectively, and yielded 51.82 g/L reducing sugars. The Celluclast 1.5 L and Novozyme 188 enzyme ratio were varied to maximize the hydrolyzed sugars. The ABE fermentation, using substrate from phosphoric acid pretreatment of corncobs, with 10 g/L glucose supplementation produced 11.64 g/L of total ABE, which was close to the control experiment using synthetic medium. This study showed that corncobs pretreated with phosphoric acid could potentially be used as a substrate without using a detoxification process.

Crosslinked polybenzimidazoles containing branching structure as membrane materials with excellent cell performance and durability for fuel cell applications

NASA Astrophysics Data System (ADS)

Hu, Meishao; Ni, Jiangpeng; Zhang, Boping; Neelakandan, Sivasubramaniyan; Wang, Lei

2018-06-01

Crosslinking is an effective method to improve the properties of high temperature proton exchange membranes based on polybenzimidazole. However, the compact structure of crosslinked polybenzimidazole hinders the phosphoric acid absorption of the membranes, resulting in a relatively poor fuel cell performance. Recently, we find that branched polymers can absorb more phosphoric acid with a larger free volume, but suffer from deteriorated mechanical strength. In this work, a new method is proposed to obtain excellent over-all properties of high temperature proton exchange membranes. A series of crosslinked polybenzimidazoles containing branching structure as membrane materials are successfully prepared for the first time. Compared with conventional crosslinked membranes, these crosslinked polybenzimidazole membranes containing branching structure exhibit a higher phosphoric acid doping level and proton conductivity, improved durability, lower swelling rate and comparable mechanical strength. In particular, the fuel cell base on the crosslinked and branched membrane with a 10% ratio of crosslinker in non-humidified hydrogen/air at 160 °C achieves a power density of 404 mW cm-2. The results indicate that the combination of crosslinking and branching is an effective approach to improve the properties of polybenzimidazole membrane materials.

Unusual Fragmentation of Pro-Ser/Thr-Containing Peptides Detected in Collision-Induced Dissociation Spectra

NASA Astrophysics Data System (ADS)

Medzihradszky, Katalin F.; Trinidad, Jonathan C.

2012-04-01

During collision-induced dissociation (CID)-, phosphoserine- and phosphothreonine-containing peptides frequently undergo neutral loss of phosphoric acid. Subsequent amide bond cleavage N-terminal to the site of phosphorylation results in a y ion with a mass 18 Da lower than the corresponding unmodified y fragment. We report here that when the phosphoserine or phosphothreonine is directly preceded by a proline, an unusual fragment with a mass 10 Da higher than the corresponding unmodified y ion is frequently observed. Accurate mass measurements are consistent with elimination of the phosphoric acid followed by fragmentation between the α carbon and the carbonyl group of the proline residue. We propose a cyclic oxazoline structure for this fragment. Our observation may be explained by the charge-directed SN2 neighboring group participation reaction proposed for the phosphoric acid elimination by Palumbo et al. [Palumbo, A. M., Tepe, J. J., Reid, G. E. Mechanistic Insights into the Multistage Gas-Phase Fragmentation Behavior of Phosphoserine- and Phosphothreonine-Containing Peptides. J. Protein Res. 7(2), 771-779 (2008)]. Considering such specific fragment ions for confirmation purposes after regular database searches may boost the confidence of peptide identifications as well as phosphorylation site assignments.

Latent fingermark detection for NaYF4:Er3+/Yb3+ upconversion phosphor synthesized by thermal decomposition route

NASA Astrophysics Data System (ADS)

Maurya, S. K.; Tiwari, S. P.; Kumar, A.; Kumar, K.

2018-04-01

The synthesis and spectroscopy of the upconverting nanoparticles, cubic NaYF4:Er3+/Yb3+ phosphor is developed for latent fingermark detection. The cubic phase of NaYF4: Er3+/Yb3+ phosphor is synthesized by thermal decomposition method using trifluoroacetate precursor with coordinating ligand octadecene and oleic acid in a mixture of technical grade. The synthesized samples showed intense green emission using 976 nm diode laser as an excitation source. Because of excellent property of luminescence in green regime the sample is used to detect the latent fingermark on a porous glass surface.

Recovery of Uranium from Wet Phosphoric Acid by Solvent Extraction Processes

DOE PAGES

Beltrami, Denis; Cote, Gérard; Mokhtari, Hamid; ...

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

40 CFR 180.910 - Inert ingredients used pre- and post-harvest; exemptions from the requirement of a tolerance.

Code of Federal Regulations, 2012 CFR

2012-07-01

..., carrier Lactic acid Solvent Lactic acid, 2-ethylhexyl ester (CAS Reg. No. 6283-86-9) Solvent Lactic acid, 2-ethylhexyl ester, (2S)- (CAS Reg. No. 186817-80-1) Solvent Lactic acid, n-propyl ester, (S); (CAS... coating agent Petroleum wax, conforming to 21 CFR 172.886(d) Coating agent Phosphoric acid Buffer...

Enhanced Emission from Li2CaSiO4:Dy3+ Phosphors by Doping with Al3+ and B3+

NASA Astrophysics Data System (ADS)

Erdoğmuş, E.

2016-05-01

Pure Li2CaSiO4, Li2CaSiO4:Dy3+ and Al3+, B3+ co-doped materials were prepared by a solid-state reaction in air at 900°C for 6 h and characterized by using powder XRD. The luminescence properties of the synthesized phosphors were measured at room temperature with a spectrofluorometer. Li2CaSiO4:Dy3+ emits at 484, 575, and 660 nm upon 352 nm excitation. The emission spectrum intensity of Dy3+ increased from 0.01 to 0.06 mol.%, and beyond 0.06 mol.%, concentration quenching was observed. Also, in this study, the effects of boric acid and aluminum oxide concentration on the photoluminescence properties of Dy3+ doped phosphors were investigated. The results showed that boric acid and aluminum oxide were effective in improving the photoluminescence intensity of Li2CaSiO4:Dy3+ compounds.

Luminescence properties of Eu 3+ and Sm 3+ coactivated Gd(III) tungstate phosphor for light-emitting diodes

NASA Astrophysics Data System (ADS)

Wei, Qiong; Chen, Donghua

2009-09-01

Rare-earth ions coactivated red phosphors Gd 0.2RE 1.8(WO 4) 3 (RE=Eu 3+ and Sm 3+) were synthesized by conventional solid-state reaction using boric acid as a flux agent. The samples were characterized by X-ray diffractometer (XRD), energy-dispersive X-ray spectrometer (EDS) and luminescence spectrometer (LS). The results showed that the Eu-Sm system exhibits higher emission intensity than those of the Eu single-doped system and Sm separate-doped system under ultraviolet (UV) radiation. Samarium(III) ions are effective in broadening and strengthened absorptions around 400 nm. Furthermore, it exhibits enhanced luminescence emission. when the mole ratio of boric acid is about 0.16, the luminescence capability is optimum. Two strongest lines at ultraviolet (394 nm) and blue (465 nm) in excitation spectra of these phosphors match well with the output wavelengths of UV and blue GaN-based light-emitting diodes (LEDs) chips.

9 CFR 319.700 - Margarine or oleomargarine. 1

Code of Federal Regulations, 2013 CFR

2013-01-01

... esterified with any or all of the following acids: acetic, acetyltartaric, citric, lactic, tartaric, and... sufficient for purpose: adipic acid; citric and lactic acids and their potassium and sodium salts; phosphoric...) Vitamin D in such quantity that the finished margarine or oleomargarine contains not less than 1,500 IU of...

9 CFR 319.700 - Margarine or oleomargarine. 1

Code of Federal Regulations, 2012 CFR

2012-01-01

... esterified with any or all of the following acids: acetic, acetyltartaric, citric, lactic, tartaric, and... sufficient for purpose: adipic acid; citric and lactic acids and their potassium and sodium salts; phosphoric...) Vitamin D in such quantity that the finished margarine or oleomargarine contains not less than 1,500 IU of...

9 CFR 319.700 - Margarine or oleomargarine. 1

Code of Federal Regulations, 2014 CFR

2014-01-01

... esterified with any or all of the following acids: acetic, acetyltartaric, citric, lactic, tartaric, and... sufficient for purpose: adipic acid; citric and lactic acids and their potassium and sodium salts; phosphoric...) Vitamin D in such quantity that the finished margarine or oleomargarine contains not less than 1,500 IU of...

UV-visible light photocatalytic properties of NaYF4:(Gd, Si)/TiO2 composites

NASA Astrophysics Data System (ADS)

Mavengere, Shielah; Kim, Jung-Sik

2018-06-01

In this study, a new novel composite photocatalyst of NaYF4:(Gd, Si)/TiO2 phosphor has been synthesized by two step method of solution combustion and sol-gel. The photocatalyst powders were characterized by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), UV-vis spectroscopy and photoluminescence (PL) spectroscopy. Raman spectroscopy confirmed the anatase TiO2 phase which remarkably increased with existence of yttrium silicate compounds between 800 cm-1 and 900 cm-1. Double-addition of Gd3+-Si4+ ions in NaYF4 host introduced sub-energy band levels with intense absorption in the ultraviolet (UV) light region. Photocatalytic activity was examined by exposing methylene blue (MB) solutions mixed with photocatalyst powders to 254 nm UV-C fluorescent lamp and 200 W visible lights. The UV and visible photocatalytic reactivity of the NaYF4:(Gd, 1% Si)/TiO2 phosphor composites showed enhanced MB degradation efficiency. The coating of NaYF4:(Gd, 1% Si) phosphor with TiO2 nanoparticles creates energy band bending at the phosphor/TiO2 interfaces. Thus, these composites exhibited enhanced absorption of UV/visible light and the separation of electron and hole pairs for efficient photocatalysis.

SEM analysis of enamel surface treated by Er:YAG laser: influence of irradiation distance.

PubMed

Souza-Gabriel, A E; Chinelatti, M A; Borsatto, M C; Pécora, J D; Palma-Dibb, R G; Corona, S A M

2008-07-01

Depending on the distance of laser tip to dental surface a specific morphological pattern should be expected. However, there have been limited reports that correlate the Er:YAG irradiation distance with dental morphology. To assess the influence of Er:YAG laser irradiation distance on enamel morphology, by means of scanning electron microscopy (SEM). Sixty human third molars were employed to obtain discs (approximately =1 mm thick) that were randomly assigned to six groups (n=10). Five groups received Er:YAG laser irradiation (80 mJ/2 Hz) for 20 s, according to the irradiation distance: 11, 12, 14, 16, or 17 mm and the control group was treated with 37% phosphoric acid for 15 s. The laser-irradiated discs were bisected. One hemi-disc was separated for superficial analysis without subsequent acid etching, and the other one, received the phosphoric acid for 15 s. Samples were prepared for SEM. Laser irradiation at 11 and 12 mm provided an evident ablation of enamel, with evident fissures and some fused areas. At 14, 16 and 17 mm the superficial topography was flatter than in the other distances. The subsequent acid etching on the lased-surface partially removed the disorganized tissue. Er:YAG laser in defocused mode promoted slight morphological alterations and seems more suitable for enamel conditioning than focused irradiation. The application of phosphoric acid on lased-enamel surface, regardless of the irradiation distance, decreased the superficial irregularities.

2-(4-Ethoxy phenyl)-4-phenyl quinoline organic phosphor for solution processed blue organic light-emitting diodes.

PubMed

Ghate, Minakshi; Kalyani, N Thejo; Dhoble, S J

2018-05-31

This paper reports the synthesis and characterization of 2-(4-ethoxyphenyl)-4-phenyl quinoline (OEt-DPQ) organic phosphor using an acid-catalyzed Friedlander reaction and the preparation of blended thin films by molecularly doping OEt-DPQ in poly(methyl methacrylate) (PMMA) at different wt%. The molecular structure of the synthesized phosphor was confirmed by Fourier transform infra-red (FTIR) spectroscopy and nuclear magnetic resonance spectra (NMR). Surface morphology and percent composition of the elements were assessed by scanning electron microscopy (SEM) and energy dispersive analysis of X-rays (EDAX). The thermal stability and melting point of OEt-DPQ and thin films were probed by thermo-gravimetric analysis (TGA)/differential thermal analysis (DTA) and were found to be 80°C and 113.6°C, respectively. UV-visible optical absorption spectra of OEt-DPQ in the solid state and blended films produced absorption bands in the range 260-340 nm, while photoluminescence (PL) spectra of OEt-DPQ in the solid state and blended thin films demonstrated blue emission that was registered at 432 nm when excited at 363-369 nm. However, solvated OEt-DPQ in chloroform, tetrahydrofuran or dichloromethane showed a blue shift of 31-43 nm. Optical absorption and emission parameters such as molar extinction coefficient (ε), energy gap (E g ), transmittance (T), reflectance (R), refractive index (n), oscillator energy (E 0 ) and oscillator strength (f), quantum yield (φ f ), oscillator energy (E 0 ), dispersion energy (E d ), Commission Internationale de l'Éclairage (CIE) co-ordinates and energy yield fluorescence (E F ) were calculated to assess the phosphor's suitability as a blue emissive material for opto-electronic applications such as organic light-emitting diodes (OLEDs), flexible displays and solid-state lighting technology. Copyright © 2018 John Wiley & Sons, Ltd.

Rare-earth free self-luminescent Ca2KZn2(VO4)3 phosphors for intense white light-emitting diodes

PubMed Central

Bharat, L. Krishna; Jeon, Soo-Kun; Krishna, Kurugundla Gopi; Yu, Jae Su

2017-01-01

The commercially available white-light-emitting diodes (WLEDs) are made with a combination of blue LEDs and yellow phosphors. These types of WLEDs lack certain properties which make them meagerly applicable for general illumination and flat panel displays. The solution for such problem is to use near-ultraviolet (NUV) chips as an excitation source because of their high excitation efficiency and good spectral distribution. Therefore, there is an active search for new phosphor materials which can be effectively excited within the NUV wavelength range (350–420 nm). In this work, novel rare-earth free self-luminescent Ca2KZn2(VO4)3 phosphors were synthesized by a citrate assisted sol-gel method at low calcination temperatures. Optical properties, internal quantum efficiency and thermal stability as well as morphology and crystal structure of Ca2KZn2(VO4)3 phosphors for their application to NUV-based WLEDs were studied. The crystal structure and phase formation were confirmed with XRD patterns and Rietveld refinement. The optical properties of these phosphor materials which can change the NUV excitation into visible yellow-green emissions were studied. The synthesized phosphors were then coated onto the surface of a NUV chip along with a blue phosphor (LiCaPO4:Eu2+) to get brighter WLEDs with a color rendering index of 94.8 and a correlated color temperature of 8549 K. PMID:28181549

Rare-earth free self-luminescent Ca2KZn2(VO4)3 phosphors for intense white light-emitting diodes.

PubMed

Bharat, L Krishna; Jeon, Soo-Kun; Krishna, Kurugundla Gopi; Yu, Jae Su

2017-02-09

The commercially available white-light-emitting diodes (WLEDs) are made with a combination of blue LEDs and yellow phosphors. These types of WLEDs lack certain properties which make them meagerly applicable for general illumination and flat panel displays. The solution for such problem is to use near-ultraviolet (NUV) chips as an excitation source because of their high excitation efficiency and good spectral distribution. Therefore, there is an active search for new phosphor materials which can be effectively excited within the NUV wavelength range (350-420 nm). In this work, novel rare-earth free self-luminescent Ca 2 KZn 2 (VO 4 ) 3 phosphors were synthesized by a citrate assisted sol-gel method at low calcination temperatures. Optical properties, internal quantum efficiency and thermal stability as well as morphology and crystal structure of Ca 2 KZn 2 (VO 4 ) 3 phosphors for their application to NUV-based WLEDs were studied. The crystal structure and phase formation were confirmed with XRD patterns and Rietveld refinement. The optical properties of these phosphor materials which can change the NUV excitation into visible yellow-green emissions were studied. The synthesized phosphors were then coated onto the surface of a NUV chip along with a blue phosphor (LiCaPO 4 :Eu 2+ ) to get brighter WLEDs with a color rendering index of 94.8 and a correlated color temperature of 8549 K.

Effects of acid etching and adhesive treatments on host-derived cysteine cathepsin activity in dentin.

PubMed

Zhang, Wenhao; Yang, Weixiang; Wu, Shuyi; Zheng, Kaibin; Liao, Weili; Chen, Boli; Yao, Ke; Liang, Guobin; Li, Yan

2014-10-01

To analyze the effects of different processes during bonding on endogenous cysteine cathepsin activity in dentin. Dentin powder, prepared from extracted human third molars, was divided into 10 groups. Two lots of dentin powder were used to detect the effects of the procedure of protein extraction on endogenous cathepsin activity. The others were used to study effects of different acid-etching or adhesive treatments on enzyme activity. Concentrations of 37% phosphoric acid or 10% phosphoric acid, two etch-and-rinse adhesive systems, and two self-etching adhesive systems were used as dentin powder treatments. The untreated mineralized dentin powder was set as the control. After treatment, the proteins of each group were extracted. The total cathepsin activity in the extracts of each group was monitored with a fluorescence reader. In the control group, there were no significant differences in cathepsin activity between the protein extract before EDTA treatment and the protein extract after EDTA treatment (p > 0.05). The cathepsin activities of the three different extracts in the 37% phosphoric acid-treated group were different from each other (p < 0.05). The two acid-etching groups and two etch-and-rinse groups showed significant enzyme activity reduction vs the control group (p < 0.05). There were no significant differences between those four groups (p > 0.05). Treating the dentin powder with any of the two self-etching adhesives resulted in an increase in cathepsin activity (p < 0.05). The activity of cysteine cathepsins can be detected in dentin powder. Treatment with EDTA during protein extraction exerted an influence on cathepsin activity. Acid etching or etch-and-rinse adhesive systems may reduce the activity of endogenous cathepsins in dentin. Self-etching adhesive systems may increase the enzyme activity.

Comparison of shear bond strength of universal adhesives on etched and nonetched enamel.

PubMed

Beltrami, Riccardo; Chiesa, Marco; Scribante, Andrea; Allegretti, Jessica; Poggio, Claudio

2016-04-06

The purpose of this study was to evaluate the effect of surface pretreatment with 37% phosphoric acid on the enamel bond strength of different universal adhesives. One hundred and sixty bovine permanent mandibular incisors freshly extracted were used as a substitute for human teeth. The materials tested in this study included 6 universal adhesives, and 2 self-etch adhesives as control. The teeth were assigned into 2 groups: In the first group, etching was performed using 37% phosphoric acid for 30 seconds. In the second group, no pretreatment agent was applied. After adhesive application, a nanohybrid composite resin was inserted into the enamel surface by packing the material into cylindrical-shaped plastic matrices. After storing, the specimens were placed in a universal testing machine. The normality of the data was calculated using the Kolmogorov-Smirnov test. Analysis of variance (ANOVA) was applied to determine whether significant differences in debond strength values existed among the various groups. Groups with phosphoric acid pretreatment showed significantly higher shear bond strength values than groups with no enamel pretreatment (p<0.001). No significant variation in shear strength values was detected when comparing the different adhesive systems applied onto enamel after orthophosphoric acid application (p>0.05). All adhesives provide similar bond strength values when enamel pretreatment is applied even if compositions are different. Bond strength values are lower than promised by manufacturers.

Utilization of Glyphosate as Phosphate Source: Biochemistry and Genetics of Bacterial Carbon-Phosphorus Lyase

PubMed Central

Zechel, David L.; Jochimsen, Bjarne

2014-01-01

SUMMARY After several decades of use of glyphosate, the active ingredient in weed killers such as Roundup, in fields, forests, and gardens, the biochemical pathway of transformation of glyphosate phosphorus to a useful phosphorus source for microorganisms has been disclosed. Glyphosate is a member of a large group of chemicals, phosphonic acids or phosphonates, which are characterized by a carbon-phosphorus bond. This is in contrast to the general phosphorus compounds utilized and metabolized by microorganisms. Here phosphorus is found as phosphoric acid or phosphate ion, phosphoric acid esters, or phosphoric acid anhydrides. The latter compounds contain phosphorus that is bound only to oxygen. Hydrolytic, oxidative, and radical-based mechanisms for carbon-phosphorus bond cleavage have been described. This review deals with the radical-based mechanism employed by the carbon-phosphorus lyase of the carbon-phosphorus lyase pathway, which involves reactions for activation of phosphonate, carbon-phosphorus bond cleavage, and further chemical transformation before a useful phosphate ion is generated in a series of seven or eight enzyme-catalyzed reactions. The phn genes, encoding the enzymes for this pathway, are widespread among bacterial species. The processes are described with emphasis on glyphosate as a substrate. Additionally, the catabolism of glyphosate is intimately connected with that of aminomethylphosphonate, which is also treated in this review. Results of physiological and genetic analyses are combined with those of bioinformatics analyses. PMID:24600043

Five-year Effects of Chlorhexidine on the In Vitro Durability of Resin/Dentin Interfaces.

PubMed

Loguercio, Alessandro D; Hass, Viviane; Gutierrez, Mario Felipe; Luque-Martinez, Issis Virginia; Szezs, Anna; Stanislawczuk, Rodrigo; Bandeca, Matheus Coelho; Reis, Alessandra

2016-01-01

To evaluate the effect of an acid containing 2% chlorhexidine (Ac/CHX) or a 2% CHX aqueous solution (Aq/CHX) on the immediate and 5-year bonding properties of resin/dentin interfaces produced by two adhesives. The presence of CHX in these interfaces was also evaluated under micro-Raman spectroscopy. Forty-two molars were ground to expose a flat dentin surface. In the control group, the surfaces were etched with conventional phosphoric acid, and Prime&Bond NT (PB) and Adper Single Bond 2 (SB) were applied. In Ac/CHX, an acid containing 2% CHX was applied after adhesive application. In the Aq/CHX group, an aqueous solution of 2% CHX was applied for 60 s after etching. After placing the restoration, specimens were prepared and tested using the microtensile bond strength test (μTBS, 0.5 mm/min) immediately or after 5 years. For nanoleakage (NL), specimens at each period were immersed in silver nitrate solution and examined by EDX-SEM. In addition, specimens at each period underwent examination for CHX using micro-Raman spectroscopy. Data were submitted to appropriate statistical analysis (a=0.05). After 5 years, NL was more pronounced in the control than in the Ac/CHX or Aq/CHX (p<0.001). Significant reductions in the μTBS were observed for all groups; however, they were more pronounced for the control (p<0.001). CHX was still present in the hybrid layers Ac/CHX or Aq/CHX groups after 5 years. The use of a 2% chlorhexidine-containing acid or the application of an aqueous CHX primer may increase the long-term stability of resin/dentin interfaces.

Interfacial micromorphological differences in hybrid layer formation between water- and solvent-based dentin bonding systems.

PubMed

Gregoire, Geneviève L; Akon, Bernadette A; Millas, Arlette

2002-06-01

Many dentin bonding systems of different compositions, and in particular containing different solvents, have been introduced to the market. Their effect on the quality of the interface requires clarification by means of comparative trials. This study investigated micromorphological differences in hybrid layer formation with a variety of commercially available water- or solvent-based dentin bonding products and their recommended compomers. Five bonding systems were used on groups of 10 teeth each as follows: group I, acetone-based system used with 36% phosphoric acid; group II, a different acetone-based system containing nano-sized particles for filler loading and used with a non-rinsing conditioner containing maleic acid; group III, the acetone-based system of group II used with 36% phosphoric acid (the only difference in the treatment for groups II and III was the acid etching system); group IV, a mixed-solvent-based system (water/ethanol) used with 37% phosphoric acid; and group V, a water-based system used with 37% phosphoric acid. Each bonding system was covered with the recommended compomer. Class I occlusal preparations were made in extracted teeth and restored with one of the above systems. Five specimens of each group were studied with optical microscopy after staining. Scanning electron microscopy was used to examine the interface of the bonding system/dentin of the other 5 teeth in each group. The optical microscopy measurements were made with a 10 x 10 reticle. A micron mark with scale was used for the scanning electron microscope. All measurements were made in microm. The following criteria were used to define a good interface: absence of voids between the different parts of the interface, uniformity of the hybrid layer, good opening of the tubuli orifices, and tag adherence to the tubuli walls. Morphological differences were found at the interface depending on dentin treatment and adhesive composition. The acetone-containing systems were associated with a continuous, gap-free hybrid layer that was linked intimately with the dentin. The tags adhered well to the tubuli walls and were often joined by side branches. In the water-based solvent systems, a lack of contact was visible between the resin tags and the tubuli walls, with some incompletely filled tubuli and some gaps in the hybrid layer. The 2 observational methods used, optical and scanning electron microscopy, proved to be complementary. Within the limitations of this study, use of the acetone-based systems after phosphoric acid etching resulted in a continuous, thick hybrid layer with reverse-cone-shaped tags in close contact with the tubuli walls. Use of the water-based systems resulted in a thinner hybrid layer with some incompletely sealed dentinal tubules.

Fabrication of Al2O3 coated 2D TiO2 nanoparticle photonic crystal layers by reverse nano-imprint lithography and plasma enhanced atomic layer deposition.

PubMed

Kim, Ki-Kang; Ko, Ki-Young; Ahn, Jinho

2013-10-01

This paper reports simple process to enhance the extraction efficiency of photoluminescence (PL) from Eu-doped yttrium oxide (Y2O3:Eu3+) thin-film phosphor (TFP). Two-dimensional (2D) photonic crystal layer (PCL) was fabricated on Y2O3:Eu3+ phosphor films by reverse nano-imprint method using TiO2 nanoparticle solution as a nano-imprint resin and a 2D hole-patterned PDMS stamp. Atomic scale controlled Al2O3 deposition was performed onto this 2D nanoparticle PCL for the optimization of the photonic crystal pattern size and stabilization of TiO2 nanoparticle column structure. As a result, the light extraction efficiency of the Y2O3:Eu3+ phosphor film was improved by 2.0 times compared to the conventional Y2O3:Eu3+ phosphor film.

Nutrient recycle from defatted microalgae (Aurantiochytrium) with hydrothermal treatment for microalgae cultivation.

PubMed

Aida, Taku Michael; Maruta, Ryouma; Tanabe, Yuuhiko; Oshima, Minori; Nonaka, Toshiyuki; Kujiraoka, Hiroki; Kumagai, Yasuaki; Ota, Masaki; Suzuki, Iwane; Watanabe, Makoto M; Inomata, Hiroshi; Smith, Richard L

2017-03-01

Defatted heterotrophic microalgae (Aurantiochytrium limacinum SR21) was treated with high temperature water (175-350°C, 10-90min) to obtain nitrogen and phosphorous nutrients as a water soluble fraction (WS). Yields of nitrogen and phosphorous recovered in WS varied from 38 to 100% and from 57 to 99%, respectively. Maximum yields of nitrogen containing compounds in WS were proteins (43%), amino acids (12%) and ammonia (60%) at treatment temperatures of 175, 250 and 350°C, respectively. Maximum yield of phosphorous in WS was 99% at a treatment temperature of 250°C. Cultivation experiments of microalgae (A. limacinum SR21) using WS obtained at 200 and 250°C showed positive growth. Water soluble fractions from hydrothermal treatment of defatted microalgae are effective nitrogen and phosphorous nutrient sources for microalgae cultivation. Copyright © 2016 Elsevier Ltd. All rights reserved.

Phosphor coated NiO-based planar inverted organometallic halide perovskite solar cells with enhanced efficiency and stability

NASA Astrophysics Data System (ADS)

Cui, Jin; Li, Pengfei; Chen, Zhifan; Cao, Kun; Li, Dan; Han, Junbo; Shen, Yan; Peng, Mingying; Fu, Yong Qing; Wang, Mingkui

2016-10-01

This work investigates non-rare-earth phosphor (Sr4Al14O25:Mn4+, 0.5%Mg) with intensively red luminescence as a luminescent down-shifting layer for perovskite solar cells. The power conversion efficiency of the fabricated device with a structure of NiO/CH3NH3PbI3/[6,6]-phenyl C61-butyric acid methyl ester/Au coated with phosphor layer shows a 10% increase as compared with that of the control devices. Importantly, the phosphor layer coating can realize UV-protection as well as waterproof capability, achieving a reduced moisture-degradation of CH3NH3PbI3 perovskite upon applying an UV irradiation. Therefore, perovskite devices using this luminescent coating show a combined enhancement in both UV down-shifting conversion and long term stability. This can be expanded as a promising encapsulation technique in the perovskite solar cell community.

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.

Tested Demonstrations.

ERIC Educational Resources Information Center

Gilbert, George L., Ed.

1982-01-01

Three chemistry demonstrations are described: (1) modification of copper catalysis demonstration apparatus; (2) experiments in gas-liquid chromatography with simple gas chromatography at room temperature; and (3) equilibria in silver arsenate-arsenic acid and silver phosphate-phosphoric acid systems. Procedures and materials needed are provided.…

40 CFR Table A-3 to Subpart A of... - Source Category List for § 98.2(a)(1)

Code of Federal Regulations, 2014 CFR

2014-07-01

... that report CO2 mass emissions year round through 40 CFR part 75 (subpart D). Adipic acid production...). Lime manufacturing (subpart S). Nitric acid production (subpart V). Petrochemical production (subpart X). Petroleum refineries (subpart Y). Phosphoric acid production (subpart Z). Silicon carbide production...

Plasmonic resonances in ordered and disordered aluminum nanocavities arrays.

NASA Astrophysics Data System (ADS)

Campuzano, R. G.; Mendoza, D.

2017-01-01

Nanocavities arrays were synthesized by electrochemical anodization of aluminum using oxalic and phosphoric acids as electrolytes. The morphology and topography of these structures were evaluated by SEM and AFM. Plasmonic properties of Al cavities arrays with different ordering and dimensions were analysed based on specular reflectivity. Al cavities arrays fabricated with phosphoric acid dramatically reduced the optical reflectivity as compared with unstructured Al. At the same time pronounced reflectivity dips were detectable in the 300nm-400nm range, which were ascribed to (0,1) plasmonic mode, and also a colored appearance in the samples is noticeably depending on the observation angle. These changes are not observed in samples made with oxalic acid and this fact was explained, based on a theoretical model, in terms that the surface plasmons are excited far in the UV range.

[Phosphoric acid ester preparations used in cattle, swine and sheep with special reference to cholinesterase activity. 4. Use of phosphoric acid esters and their effect on acetylcholinesterase activity in sheep].

PubMed

Mieth, K; Beier, D; Losch, K

1975-01-01

The use of organophosphorus preparations for the control of ectoparasites and endoparasites of sheep, particularly systemic application, is discussed. Experiments on 13 groups of sheep with five preparations produced in the German Democratic Republic in various formulations and concentrations showed that external application had good contact activity, but little was absorbed. Acetylcholinesterase activity was not inhibited, except by pour-on application of doses several times the normal dose. The preparations were arranged in order of cholinesterase inhibition. In contrast to cattle, diminished cholinesterase activity was unreliable as in indicator of systemic toxicity of organophosphorus preparations in sheep.

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.