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Sample records for hydroxide directed routes

  1. Highly stable layered double hydroxide colloids: a direct aqueous synthesis route from hybrid polyion complex micelles.

    PubMed

    Layrac, Géraldine; Destarac, Mathias; Gérardin, Corine; Tichit, Didier

    2014-08-19

    Aqueous suspensions of highly stable Mg/Al layered double hydroxide (LDH) nanoparticles were obtained via a direct and fully colloidal route using asymmetric poly(acrylic acid)-b-poly(acrylamide) (PAA-b-PAM) double hydrophilic block copolymers (DHBCs) as growth and stabilizing agents. We showed that hybrid polyion complex (HPIC) micelles constituted of almost only Al(3+) were first formed when mixing solutions of Mg(2+) and Al(3+) cations and PAA3000-b-PAM10000 due to the preferential complexation of the trivalent cations. Then mineralization performed by progressive hydroxylation with NaOH transformed the simple DHBC/Al(3+) HPIC micelles into DHBC/aluminum hydroxide colloids, in which Mg(2+) ions were progressively introduced upon further hydroxylation leading to the Mg-Al LDH phase. The whole process of LDH formation occurred then within the confined environment of the aqueous complex colloids. The hydrodynamic diameter of the DHBC/LDH colloids could be controlled: it decreased from 530 nm down to 60 nm when the metal complexing ratio R (R = AA/(Mg + Al)) increased from 0.27 to 1. This was accompanied by a decrease of the average size of individual LDH particles as R increased (for example from 35 nm at R = 0.27 down to 17 nm at R = 0.33), together with a progressive favored intercalation of polyacrylate rather than chloride ions in the interlayer space of the LDH phase. The DHBC/LDH colloids have interesting properties for biomedical applications, that is, high colloidal stability as a function of time, stability in phosphate buffered saline solution, as well as the required size distribution for sterilization by filtration. Therefore, they could be used as colloidal drug delivery systems, especially for hydrosoluble negatively charged drugs.

  2. Simple route for the synthesis of supercapacitive Co-Ni mixed hydroxide thin films

    SciTech Connect

    Dubal, D.P.; Jagadale, A.D.; Patil, S.V.; Lokhande, C.D.

    2012-05-15

    Highlights: Black-Right-Pointing-Pointer Novel method for deposition of Co-Ni mixed hydroxide. Black-Right-Pointing-Pointer Nanoparticle network of Co-Ni hydroxide. Black-Right-Pointing-Pointer High specific capacitance of 672 F g{sup -1}. Black-Right-Pointing-Pointer High discharge/charge rates. -- Abstract: Facile synthesis of Co-Ni mixed hydroxides films with interconnected nanoparticles networks through two step route is successfully established. These films have been characterized by X-ray diffraction (XRD), Fourier transform infrared technique (FTIR), scanning electron microscopy (SEM) and wettability test. Co-Ni film formation is confirmed from XRD and FTIR study. SEM shows that the surface of Co-Ni films is composed of interconnected nanoparticles. Contact angle measurement revealed the hydrophilic nature of films which is feasible for the supercapacitor. The electrochemical performance of the film is evaluated by cyclic voltammetry, and constant-current charge/discharge cycling techniques. Specific capacitance of the Co-Ni mixed hydroxide electrode achieved 672 F g{sup -1}. Impedance analysis shows that Co-Ni mixed hydroxide electrode provides less resistance for the intercalation and de-intercalation of ions. The Co-Ni mixed electrode exhibited good charge/discharge rate at different current densities. The results demonstrated that Co-Ni mixed hydroxide composite is very promising for the next generation high performance electrochemical supercapacitors.

  3. Direct ethanol fuel cell using hydrotalcite clay as a hydroxide ion conductive electrolyte.

    PubMed

    Tadanaga, Kiyoharu; Furukawa, Yoshihiro; Hayashi, Akitoshi; Tatsumisago, Masahiro

    2010-10-15

    An alkaline-type direct ethanol fuel cell (DEFC) using a natural clay electrolyte with non-platinum catalysts is proposed. So-called hydrotalcite clay, Mg–Al layered double hydroxide intercalated with CO₃²⁻, is shown to be a hydroxide ion conductor. An alkaline-type DEFC using this natural clay as the electrolyte and aqueous solution of ethanol and potassium hydroxide as a source of fuel exhibits excellent electrochemical performance from room temperature to 80 °C.

  4. Synthesis and characterization of cadmium hydroxide nano-nest by chemical route

    NASA Astrophysics Data System (ADS)

    Salunkhe, R. R.; Patil, U. M.; Gujar, T. P.; Lokhande, C. D.

    2009-01-01

    A facile chemical route based on room temperature chemical bath deposition (CBD) was developed to deposit the Cd(OH) 2 nano-nest. The growth mechanism follows two-stage crystallization with initial growth of nucleation centers, followed by subsequent anisotropic growth. The nano-nest morphological evolution of Cd(OH) 2 on different substrates has been carried out. These films have been characterized by the techniques; such as X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), optical absorption, contact angle measurement and thermoelectric power (TEP) measurements. The X-ray diffraction study revealed that the as deposited film consists of cadmium hydroxide (Cd(OH) 2) phase. The nano-nest consisted of wires with nearly uniform in dimensions, with diameter around 30 nm and length of few microns. As-deposited Cd(OH) 2 film used in this study showed water contact angle of 66°. The optical bandgap was found to be 3.2 eV, with n-type electrical conductivity as confirmed from thermo-emf measurements.

  5. Novel route for layered double hydroxides preparation by enzymatic decomposition of urea

    NASA Astrophysics Data System (ADS)

    Vial, S.; Prevot, V.; Forano, C.

    2006-05-01

    This study presents a new route for the preparation of a series of layered double hydroxide materials with controlled textural properties. It concerns the biogenesis of hydrotalcite like phases by Jack bean urease through the enzymatic decomposition process of urea. Different conditions of LDH biogenesis are investigated (urease activity, urea concentration). A comparative study with the precipitation method based on the thermal decomposition of urea (90 °C) is conducted in order to asses the effect of the various urea hydrolysis conditions (kinetic, temperature) and the presence of enzyme in the reaction medium on the structural and textural properties of the as prepared LDH materials. Mechanisms of formation of the LDH phases for both synthesis processes are discussed on basis of their pH control. The PXRD and SEM analysis of samples prepared by the thermal process evidence higher crystallinity and greater particle sizes than LDH obtained in mild biogenic conditions. In the latter case, presence of urease or effect of some M(II) metals may inhibit the crystallization.

  6. New synthetic route to Mg–Al–CO{sub 3} layered double hydroxide using magnesite

    SciTech Connect

    Wang, Xiaobo; Bai, Zhimin; Zhao, Dong; Chai, Yupu; Guo, Man; Zhang, Jingyu

    2013-03-15

    Highlights: ► The use of magnesite to prepare Mg–Al–CO{sub 3} LDH is novel. ► The result sample is systematically studied. ► Furthermore, the cost of preparing Mg–Al–CO{sub 3} LDH may be reduced through this synthetic route. ► In the synthesis process, there is no CO{sub 2} released. That is significant to environmental protection. - Abstract: A novel synthesis of Mg–Al–CO{sub 3} layered double hydroxide (LDH) through chemical precipitation and hydrothermal methods has been investigated in this paper. The advantages of this method are using magnesite as magnesium source and no CO{sub 2} released in the process of preparation. Mg–Al–CO{sub 3} LDH (ZY) prepared under the optimized condition (the molar ratio of magnesite and Al(NO{sub 3}){sub 3}·9H{sub 2}O was 2.5:1; the aging time and temperature were 16 h and 100 °C, respectively) was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermo-gravimetric and differential thermal analyser (TG–DTA) and scanning electron microscope (SEM). The crystal morphology of the prepared LDH displays platelet-like structure with a hexagonal shape, which is agreed with the LDH produced by industrial chemicals. Through elemental analysis and inductively coupled plasma-atomic emission spectrometry (ICP-AES), the chemical formula of ZY is determined as Mg{sub 0.70}Al{sub 0.30}(OH){sub 2}(CO{sub 3}){sub 0.15}·0.6H{sub 2}O.

  7. Automatic Extraction of Destinations, Origins and Route Parts from Human Generated Route Directions

    NASA Astrophysics Data System (ADS)

    Zhang, Xiao; Mitra, Prasenjit; Klippel, Alexander; Maceachren, Alan

    Researchers from the cognitive and spatial sciences are studying text descriptions of movement patterns in order to examine how humans communicate and understand spatial information. In particular, route directions offer a rich source of information on how cognitive systems conceptualize movement patterns by segmenting them into meaningful parts. Route directions are composed using a plethora of cognitive spatial organization principles: changing levels of granularity, hierarchical organization, incorporation of cognitively and perceptually salient elements, and so forth. Identifying such information in text documents automatically is crucial for enabling machine-understanding of human spatial language. The benefits are: a) creating opportunities for large-scale studies of human linguistic behavior; b) extracting and georeferencing salient entities (landmarks) that are used by human route direction providers; c) developing methods to translate route directions to sketches and maps; and d) enabling queries on large corpora of crawled/analyzed movement data. In this paper, we introduce our approach and implementations that bring us closer to the goal of automatically processing linguistic route directions. We report on research directed at one part of the larger problem, that is, extracting the three most critical parts of route directions and movement patterns in general: origin, destination, and route parts. We use machine-learning based algorithms to extract these parts of routes, including, for example, destination names and types. We prove the effectiveness of our approach in several experiments using hand-tagged corpora.

  8. Tuning complex transition metal hydroxide nanostructures as active catalysts for water oxidation by a laser-chemical route.

    PubMed

    Niu, Kai-Yang; Lin, Feng; Jung, Suho; Fang, Liang; Nordlund, Dennis; McCrory, Charles C L; Weng, Tsu-Chien; Ercius, Peter; Doeff, Marca M; Zheng, Haimei

    2015-04-01

    Diverse transition metal hydroxide nanostructures were synthesized by laser-induced hydrolysis in a liquid precursor solution for alkaline oxygen evolution reaction (OER). Several active OER catalysts with fine control of composition, structure, and valence state were obtained including (Lix)[Ni0.66Mn0.34(OH)2](NO3)(CO3) · mH2O, Lix[Ni0.67Co0.33(OH)2](NO3)0.25(ORO)0.35 · mH2O, etc. An operate overpotential less than 0.34 V at current density of 10 mA cm(-2) was achieved. Such a controllable laser-chemical route for assessing complex nanostructures in liquids opens many opportunities to design novel functional materials for advanced applications.

  9. NLR activation takes a direct route.

    PubMed

    Monie, Tom P

    2013-03-01

    For the first time there is now clear biochemical and biophysical evidence indicating that members of the nucleotide-binding domain and leucine-rich repeat containing (NLR) family can be activated as a result of direct interaction between the receptor and ligand. NLRX1 leucine-rich repeats bind to RNA; murine NAIP (NLR family, apoptosis inhibitory protein) 5 binds flagellin directly; and NOD (nucleotide-binding oligomerization domain containing) 1 and NOD2 may interact directly with fragments of peptidoglycan. It remains to be seen if NLRP3 has a specific ligand, but progress has been made in addressing its mechanism of activation, with cellular imbalances and mitochondrial dysfunction being important. This review updates our understanding of NLR activation in light of these recent advances and their impact on the NLR research. PMID:23394939

  10. Direct-To Tool for En Route Controllers

    NASA Technical Reports Server (NTRS)

    Erzberger, Heinz; McNally, David; Foster, Michelle

    2002-01-01

    This paper describes a new automation tool for en route air traffic controllers, called the Direct-To Tool. The Tool is designed to reduce the time of flight and fuel consumption for aircraft flying in en route airspace. It provides each controller with the identities of aircraft in his/her sector, which can reduce their time en route by bypassing dog-legged route segments and flying "direct to" a waypoint closer to the destination airport. The Tool uses its build-in conflict probing capability to determine if the improved route is free of conflicts with other aircraft. The Tool's graphical computer interface enables the controller to enter a direct-to clearance by a simple point and click action. Because of its low workload and convenience, this method is strongly favored by controllers The Tool has been running since January with live radar data received at NASA from the Fort Worth Air Route Traffic Control Center. For aircraft operating in the Fort Worth Center, the Tool has the potential to save in excess of 500,000 in-flight minutes per year. A provisional patent application for this Tool has been filed. A field task in planned for the last quarter of this year.

  11. Aluminum doped nickel oxide thin film with improved electrochromic performance from layered double hydroxides precursor in situ pyrolytic route

    NASA Astrophysics Data System (ADS)

    Shi, Jingjing; Lai, Lincong; Zhang, Ping; Li, Hailong; Qin, Yumei; Gao, Yuanchunxue; Luo, Lei; Lu, Jun

    2016-09-01

    Electrochromic materials with unique performance arouse great interest on account of potential application values in smart window, low-power display, automobile anti-glare rearview mirror, and e-papers. In this paper, high-performing Al-doped NiO porous electrochromic film grown on ITO substrate has been prepared via a layered double hydroxides(LDHs) precursor in situ pyrolytic route. The Al3+ ions distributed homogenously within the NiO matrix can significantly influence the crystallinity of Ni-Al LDH and NiO:Al3+ films. The electrochromic performance of the films were evaluated by means of UV-vis absorption spectroscopy, cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and chronoamperometry(CA) measurements. In addition, the ratio of Ni3+/Ni2+ also varies with Al content which can lead to different electrochemical performances. Among the as-prepared films, NiO film prepared from Ni-Al (19:1) LDH show the best electrochromic performance with a high transparency of 96%, large optical modulation range (58.4%), fast switching speed (bleaching/coloration times are 1.8/4.2 s, respectively) and excellent durability (30% decrease after 2000 cycles). The improved performance was owed to the synergy of large NiO film specific surface area and porous morphology, as well as Al doping stifled the formation of Ni3+ making bleached state more pure. This LDHs precursor pyrolytic method is simple, low-cost and environmental benign and is feasible for the preparation of NiO:Al and other Al-doped oxide thin film.

  12. Simvastatin versus Calcium Hydroxide Direct Pulp Capping of Human Primary Molars: A Randomized Clinical Trial

    PubMed Central

    Asl Aminabadi, Naser; Maljaei, Ensiyeh; Erfanparast, Leila; Ala Aghbali, Amir; Hamishehkar, Hamed; Najafpour, Ebrahim

    2013-01-01

    Background and aims The aim of present study was to investigate pulp-dentin complex reactions following direct pulp capping (DPC) with calcium hydroxide [Ca(OH)2] and simvastatin as pulp-capping materials in the primary human molars. Materials and methods 120 primary molar teeth which had to be extracted for orthodontic reasons were randomly allocated into four groups. Group Ι as a control, underwent DPC with calcium hydroxide. The dental pulp in group ІІ, ІІІ and ІV were directly capped with simvastatin-based materials at concentrations of 1, 5 and 10 µM, respectively. All of the teeth were restored with stainless steel crown. After a mean period of 7.41 months teeth were extracted and processed for histological examination and categorized in terms of hard tissue formation and pulp inflammation. Results Teeth in group I had statistically favorable outcomes in hard tissue formation and pulp inflammation than did the groups ІІ, ІІІ and ІV (P < 0.001). Considering three different concentrations of simvastatin, the result showed a dose dependent trend. Teeth in group ІV showed significantly lower rates of hard tissue formation and higher rates of pulp inflammation and necrosis compared to those of groups ІІ (P < 0.05). Conclusion The findings of this study depicted that healing with no inflammation and hard tissue formation following statin treatment occurs with a lower rate than that with the calcium hydroxide. PMID:23487477

  13. Layered double hydroxide stability. 2. Formation of Cr(III)-containing layered double hydroxides directly from solution

    NASA Technical Reports Server (NTRS)

    Boclair, J. W.; Braterman, P. S.; Jiang, J.; Lou, S.; Yarberry, F.

    1999-01-01

    Solutions containing divalent metal [M(II) = Mg2+, Zn2+, Co2+, Ni2+, Mn2+] chlorides and CrCl3 6H2O were titrated with NaOH to yield, for M(II) = Zn, Co, and Ni, hydrotalcite-like layered double hydroxides (LDHs), [[M(II)]1-z[Cr(III)]z(OH)2][Cl]z yH2O, in a single step, without intermediate formation of chromium hydroxide. Analysis of the resultant titration curves yields solubility constants for these compounds. These are in the order Zn < Ni approximately Co, with a clear preference for formation of the phase with z = 1/3. With Mg2+ as chloride, titration gives a mixture of Cr(OH)3 and Mg(OH)2, but the metal sulfates give Mg2Cr(OH)6 1/2(SO4) by a two-step process. Titrimetric and spectroscopic evidence suggests short-range cation order in the one-step LDH systems.

  14. Direct fermentation route for the production of acrylic acid.

    PubMed

    Chu, Hun Su; Ahn, Jin-Ho; Yun, Jiae; Choi, In Suk; Nam, Tae-Wook; Cho, Kwang Myung

    2015-11-01

    There have been growing concerns regarding the limited fossil resources and global climate changes resulting from modern civilization. Currently, finding renewable alternatives to conventional petrochemical processes has become one of the major focus areas of the global chemical industry sector. Since over 4.2 million tons of acrylic acid (AA) is annually employed for the manufacture of various products via petrochemical processes, this chemical has been the target of efforts to replace the petrochemical route by ecofriendly processes. However, there has been limited success in developing an approach combining the biological production of 3-hydroxypropionic acid (3-HP) and its chemical conversion to AA. Here, we report the first direct fermentative route for producing 0.12 g/L of AA from glucose via 3-HP, 3-HP-CoA, and Acryloyl-CoA, leading to a strain of Escherichia coli capable of directly producing acrylic acid. This route was developed through extensive screening of key enzymes and designing a novel metabolic pathway for AA. PMID:26319589

  15. Mechanistic insights into the dissociation and decomposition of carbonic acid in water via the hydroxide route: an ab initio metadynamics study.

    PubMed

    Galib, Mirza; Hanna, Gabriel

    2011-12-22

    The dissociation and decomposition of carbonic acid (H2CO3) in water are important reactions in the pH regulation in blood, CO2 transport in biological systems, and the global carbon cycle. H2CO3 is known to have three conformers [cis-cis (CC), cis-trans (CT), and trans-trans (TT)], but their individual reaction dynamics in water has not been probed experimentally. In this paper, we have investigated the energetics and mechanisms of the conformational changes, dissociation (H2CO3 -->/<-- HCO3(-) + H(+)), and decomposition via the hydroxide route (HCO3(-) --> CO2+OH(-)) of all three conformers of H2CO3 in water using Car-Parrinello molecular dynamics (CPMD) in conjunction with metadynamics. It was found that, unlike in the gas phase, the interconversion between the various conformers occurs via two different pathways, one involving a change in one of the two dihedral angles (O=C-O-H) and the other a proton transfer through a hydrogen-bond wire. The free energy barriers/changes for the various conformational changes via the first pathway were calculated and contrasted with the previously calculated values for the gas phase. The CT and TT conformers were found to undergo decomposition in water via a two-step process: first, the dissociation and then the decomposition of HCO3(-) into CO2 and OH(-). The CC conformer does not directly decompose but first undergoes a conformational change to CT or TT prior to decomposition. This is in contrast with the concerted mechanism proposed for the gas phase, which involves a dehydroxylation of one of the OH groups and a simultaneous deprotonation of the other OH group to yield CO2 and H2O. The dissociation in water was seen to involve the repeated formation and breakage of a hydrogen-bond wire with neighboring water molecules, whereas the decomposition is initiated by the diffusion of H(+) away from HCO3(-); this decomposition mechanism differs from that proposed for the water route dehydration (HCO3(-) + H3O(+) --> CO2 + H2O

  16. Mechanistic insights into the dissociation and decomposition of carbonic acid in water via the hydroxide route: an ab initio metadynamics study.

    PubMed

    Galib, Mirza; Hanna, Gabriel

    2011-12-22

    The dissociation and decomposition of carbonic acid (H2CO3) in water are important reactions in the pH regulation in blood, CO2 transport in biological systems, and the global carbon cycle. H2CO3 is known to have three conformers [cis-cis (CC), cis-trans (CT), and trans-trans (TT)], but their individual reaction dynamics in water has not been probed experimentally. In this paper, we have investigated the energetics and mechanisms of the conformational changes, dissociation (H2CO3 -->/<-- HCO3(-) + H(+)), and decomposition via the hydroxide route (HCO3(-) --> CO2+OH(-)) of all three conformers of H2CO3 in water using Car-Parrinello molecular dynamics (CPMD) in conjunction with metadynamics. It was found that, unlike in the gas phase, the interconversion between the various conformers occurs via two different pathways, one involving a change in one of the two dihedral angles (O=C-O-H) and the other a proton transfer through a hydrogen-bond wire. The free energy barriers/changes for the various conformational changes via the first pathway were calculated and contrasted with the previously calculated values for the gas phase. The CT and TT conformers were found to undergo decomposition in water via a two-step process: first, the dissociation and then the decomposition of HCO3(-) into CO2 and OH(-). The CC conformer does not directly decompose but first undergoes a conformational change to CT or TT prior to decomposition. This is in contrast with the concerted mechanism proposed for the gas phase, which involves a dehydroxylation of one of the OH groups and a simultaneous deprotonation of the other OH group to yield CO2 and H2O. The dissociation in water was seen to involve the repeated formation and breakage of a hydrogen-bond wire with neighboring water molecules, whereas the decomposition is initiated by the diffusion of H(+) away from HCO3(-); this decomposition mechanism differs from that proposed for the water route dehydration (HCO3(-) + H3O(+) --> CO2 + H2O

  17. Direct observation of grafting interlayer phosphate in Mg/Al layered double hydroxides

    SciTech Connect

    Shimamura, Akihiro; Kanezaki, Eiji; Jones, Mark I.; Metson, James B.

    2012-02-15

    The grafting of interlayer phosphate in synthetic Mg/Al layered double hydroxides with interlayer hydrogen phosphate (LDH-HPO{sub 4}) has been studied by XRD, TG/DTA, FT-IR, XPS and XANES. The basal spacing of crystalline LDH-HPO{sub 4} decreases in two stages with increasing temperature, from 1.06 nm to 0.82 nm at 333 K in the first transition, and to 0.722 nm at 453 K in the second. The first stage occurs due to the loss of interlayer water and rearrangement of the interlayer HPO{sub 4}{sup 2-}. In the second transition, the interlayer phosphate is grafted to the layer by the formation of direct bonding to metal cations in the layer, accompanied by a change in polytype of the crystalline structure. The grafted phosphate becomes immobilized and cannot be removed by anion-exchange with 1-octanesulfonate. The LDH is amorphous at 743 K but decomposes to Mg{sub 3}(PO{sub 4}){sub 2}, AlPO{sub 4}, MgO and MgAl{sub 2}O{sub 4} after heated to 1273 K. - Graphical abstract: The cross section of the synthetic Mg, Al layered double hydroxides in Phase 1, with interlayer hydrogen phosphate Phase 2, and with grafted phosphate, Phase 3. Highlights: Black-Right-Pointing-Pointer The grafting of hydrogen phosphate intercalated Mg/Al-LDH has been studied. Black-Right-Pointing-Pointer The basal spacing of crystalline LDH-HPO{sub 4} decreases in two stages with increasing temperature. Black-Right-Pointing-Pointer The first decrease is due to loss of interlayer water, the second is attributed to phosphate grafting. Black-Right-Pointing-Pointer The grafted interlayer phosphate becomes immobilized and cannot be removed by anion-exchange.

  18. Nestin expressions of exposed pulp after direct pulp capping by calcium hydroxide and platelet rich plasma

    PubMed Central

    Puspita, Sartika; Utoro, Totok; Haniastuti, Tetiana

    2016-01-01

    Objective: The aim of this study was to evaluate nestin expression of pulp tissue following direct pulp capping with platelet-rich plasma (PRP). Materials and Methods: The thirty sound teeth from Sprague-Dawley rats were used and divided into two groups: Groups 1, teeth were capped with calcium hydroxide/Ca(OH)2 (n = 15) and Group 2 with PRP (n = 15). After 1st, 7th, and 21st days, respectively, 5 teeth each group (American Dental Association 41) were processed for light microscopic examination. Expressions of nestin were assessed by immunohistochemical techniques. Results: Nestin expression of Ca(OH)2 on the distance place of exposure at 1st and 7th days were 80% and at 21st day were 60%. Nestin expression of PRP on the distance place at 1st day was 80%, 7th 100%, and 21st day was 80%. At day 21 observation, Kruskal–Wallis test shows nestin expression was increased significantly in PRP groups (P < 0.05), but it was not increase significantly compare with Ca(OH)2. Conclusion: PRP had ability as a direct pulp capping material to induce nestin expression. PMID:27403050

  19. Aluminum Hydroxide and Magnesium Hydroxide

    MedlinePlus

    Aluminum Hydroxide, Magnesium Hydroxide are antacids used together to relieve heartburn, acid indigestion, and upset stomach. They ... They combine with stomach acid and neutralize it. Aluminum Hydroxide, Magnesium Hydroxide are available without a prescription. ...

  20. Neutron structural characterization, inversion degree and transport properties of NiMn{sub 2}O{sub 4} spinel prepared by the hydroxide route

    SciTech Connect

    Sagua, A.; Lescano, Gabriela M.; Alonso, J.A.; Martínez-Coronado, R.; Fernández-Díaz, M.T.; Morán, E.

    2012-06-15

    Graphical abstract: A pure specimen has been synthesized by the hydroxide route. This spinel, studied by NPD, shows an important inversion degree, λ = 0.80. A bond-valence study shows that the tetrahedral Mn ions are divalent whereas the octahedral Mn and Ni are slightly oxidized from the expected 3+ and 2+ values, respectively. The mixed valence Mn{sup 3+}/Mn{sup 4+} accounts for a hopping mechanism between adjacent octahedral sites, leading to a significant conductivity. Highlights: ► A low-temperature hydroxide route allowed preparing almost pure specimens of NiMn{sub 2}O{sub 4}. ► NPD essential to determine inversion degree; contrasting Ni and Mn for neutrons. ► Bond valence establishes valence state of octahedral and tetrahedral Ni and Mn ions. ► Thermal analysis, transport measurements complement characterization of this oxide. ► A structure–properties relationship is established. -- Abstract: The title compound has been synthesized by the hydroxide route. The crystal structure has been investigated at room temperature from high-resolution neutron powder diffraction (NPD) data. It crystallizes in a cubic spinel structure, space group Fd3{sup ¯}m, Z = 8, with a = 8.3940(2) Å at 295 K. The crystallographic formula is (Ni{sub 0.202(1)}Mn{sub 0.798(1)}){sub 8a}(Ni{sub 0.790(1)}Mn{sub 1.210(1)}){sub 16d}O{sub 4} where 8a and 16d stand for the tetrahedral and octahedral sites of the spinel structure, respectively. There is a significant inversion degree of the spinel structure, λ = 0.80. In fact, the variable parameter for the oxygen position, u = 0.2636(4), is far from that expected (u = 0.25) for normal spinels. From a bond-valence study, it seems that the valence distribution in NiMn{sub 2}O{sub 4} spinel is not as trivial as expected (Ni{sup 2+} and Mn{sup 3+}), but clearly the tetrahedral Mn ions are divalent whereas the octahedral Mn and Ni are slightly oxidized from the expected +3 and +2 values, respectively. The mixed valence observed at

  1. Strategies for Selecting Routes through Real-World Environments: Relative Topography, Initial Route Straightness, and Cardinal Direction.

    PubMed

    Brunyé, Tad T; Collier, Zachary A; Cantelon, Julie; Holmes, Amanda; Wood, Matthew D; Linkov, Igor; Taylor, Holly A

    2015-01-01

    Previous research has demonstrated that route planners use several reliable strategies for selecting between alternate routes. Strategies include selecting straight rather than winding routes leaving an origin, selecting generally south- rather than north-going routes, and selecting routes that avoid traversal of complex topography. The contribution of this paper is characterizing the relative influence and potential interactions of these strategies. We also examine whether individual differences would predict any strategy reliance. Results showed evidence for independent and additive influences of all three strategies, with a strong influence of topography and initial segment straightness, and relatively weak influence of cardinal direction. Additively, routes were also disproportionately selected when they traversed relatively flat regions, had relatively straight initial segments, and went generally south rather than north. Two individual differences, extraversion and sense of direction, predicted the extent of some effects. Under real-world conditions navigators indeed consider a route's initial straightness, cardinal direction, and topography, but these cues differ in relative influence and vary in their application across individuals.

  2. Strategies for Selecting Routes through Real-World Environments: Relative Topography, Initial Route Straightness, and Cardinal Direction

    PubMed Central

    Brunyé, Tad T.; Collier, Zachary A.; Cantelon, Julie; Holmes, Amanda; Wood, Matthew D.; Linkov, Igor; Taylor, Holly A.

    2015-01-01

    Previous research has demonstrated that route planners use several reliable strategies for selecting between alternate routes. Strategies include selecting straight rather than winding routes leaving an origin, selecting generally south- rather than north-going routes, and selecting routes that avoid traversal of complex topography. The contribution of this paper is characterizing the relative influence and potential interactions of these strategies. We also examine whether individual differences would predict any strategy reliance. Results showed evidence for independent and additive influences of all three strategies, with a strong influence of topography and initial segment straightness, and relatively weak influence of cardinal direction. Additively, routes were also disproportionately selected when they traversed relatively flat regions, had relatively straight initial segments, and went generally south rather than north. Two individual differences, extraversion and sense of direction, predicted the extent of some effects. Under real-world conditions navigators indeed consider a route’s initial straightness, cardinal direction, and topography, but these cues differ in relative influence and vary in their application across individuals. PMID:25992685

  3. Morphology-controlled synthesis of nanostructured zinc hydroxide fluoride via a microwave-assisted ionic liquid route

    NASA Astrophysics Data System (ADS)

    Zhang, Songtao; Zheng, Mingbo; Song, Jiakui; Li, Nianwu; Lu, Hongling; Cao, Jieming

    2014-12-01

    Zinc hydroxide fluoride (Zn(OH)F) with multiform morphologies such as flower-like particles, pumpkin-like aggregates, and hollow orange-like aggregates are prepared by a microwave-assisted ionic liquid method. During synthesis, microwave irradiation accelerates the reaction rate and shortens the reaction time. 1-Butyl-3-methylimidazolium tetrafluoroborate ([Bmim][BF4]) or 1-2-hydroxylethyl-3-methylimidazolium tetrafluoroborate ([C2OHmim][BF4]) is used as both reactant and template. Experimental results indicate that the morphology evolution of Zn(OH)F is mainly controlled by the concentration of zinc acetate solution. A possible mechanism underlying the formation of nanostructured Zn(OH)F with diverse morphologies is proposed. Furthermore, nanoporous ZnO is obtained by the thermal decomposition of as-prepared Zn(OH)F in air, and the morphology is well retained.

  4. Composite-hydroxide-mediated approach an effective synthesis route for BaTiO3 functional nanomaterials

    NASA Astrophysics Data System (ADS)

    Khan, Taj Muhammad; Zakria, M.; Shakoor, Rana. I.; Hussain, Shabbir

    2016-04-01

    This paper describes synthesis of the functional BaTiO3 (BT) nanostructures by composite-hydroxide-mediated (CHM) approach. The effect of processing temperature on the nucleation and the optical, structural properties is investigated. The nanostructures prepared at various temperatures (180, 220 and 250 °C) are thermally stable and nucleate in different morphologies, which shows a temperature-dependent mechanism of the CHM approach. The nanostructures are cubic in nature with an average particle size in the range of 97-250 nm. The local crystal structure investigated by Raman spectroscopy reveals a certain degree of tetragonality on atomic scale in the local phase structure. The micrographs of scanning electron microscopy (SEM) indicate formation of the nanocuboids at 180 and 220 °C with larger particle size. At 250 °C, the product shows ball-like spherical morphology. Energy-dispersive X-ray (EDX) confirms the existence of Ba, Ti and O elements in the product, which indicates a chemically pure product. Further signature on the formation, purity and chemical bonding is obtained from FT-IR spectroscopy. Based on these experimental results, size, morphology manipulation and possible growth mechanisms are proposed with CHM at low temperature and without surfactant.

  5. Layered-metal-hydroxide nanosheet arrays with controlled nanostructures to assist direct electronic communication at biointerfaces.

    PubMed

    An, Zhe; Lu, Shan; Zhao, Liwei; He, Jing

    2011-10-18

    In this work, ordered vertical arrays of layered double hydroxide (LDH) nanosheets have been developed to achieve electron transfer (eT) at biointerfaces in electrochemical devices. It is found that tailoring the gap size of LDH nanosheet arrays could significantly promote the eT rate. This research has successfully extended nanomaterials for efficient modifications of electrode surfaces from nanoparticles, nanowires, nanorods, and nanotubes to nanosheets.

  6. Synthesis and characterization of sulfate and dodecylbenzenesulfonate intercalated zinc-iron layered double hydroxides by one-step coprecipitation route

    SciTech Connect

    Zhang Hui Wen Xing; Wang Yingxia

    2007-05-15

    Inorganic sulfate- and organic dodecylbenzenesulfonate (DBS)-intercalated zinc-iron layered double hydroxides (LDHs) materials were prepared by one-step coprecipitation method from a mixed salt solutions containing Zn(II), Fe(II) and Fe(III) salts. The as-prepared samples have been characterized by X-ray powder diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), low-temperature nitrogen adsorption, scanning electron microscopy (SEM), inductively coupled plasma emission spectroscopy (ICP), and Moessbauer spectroscopy (MS). The XRD analyses demonstrate the typical LDH-like layered structural characteristics of both products. The room temperature MS results reveal the characteristics of both the Fe(II) and Fe(III) species for SO{sub 4} {sup 2-}-containing product, while only the Fe(III) characteristic for DBS-containing one. The combination characterization results and Rietveld analysis illustrate that the SO{sub 4} {sup 2-}-containing product possesses the Green Rust two (GR2)-like crystal structure with an approximate chemical composition of [Zn{sub 0.435}.Fe{sup II} {sub 0.094}.Fe{sup III} {sub 0.470}.(OH){sub 2}].(SO{sub 4} {sup 2-}){sub 0.235}.1.0H{sub 2}O, while the DBS-containing one exhibits the common LDH compound-like structure. The contact angle measurement indicates the evident hydrophobic properties of DBS-containing nanocomposite, compared with SO{sub 4} {sup 2-}-containing product, due to the modification of the internal and external surface of LDHs by the organic hydrophobic chain of DBS. - Graphical abstract: For Zn{sup 2+}-Fe{sup 2+}-Fe{sup 3+} GR2(SO{sub 4} {sup 2-}), according to the derived chemical formula, Fe{sup 3+} was arranged at 1a (0, 0, 0) position, while all Zn{sup 2+} were in 2d position with the occupancy 0.645, and the left part of 2d positions were taken by Fe{sup 2+}/Fe{sup 3+}.

  7. Direct Photonic-Plasmonic Coupling and Routing in Single Nanowires

    SciTech Connect

    Yan, Rouxue; Pausauskie, Peter; Huang, Jiaxing; Yang, Piedong

    2009-10-20

    Metallic nanoscale structures are capable of supporting surface plasmon polaritons (SPPs), propagating collective electron oscillations with tight spatial confinement at the metal surface. SPPs represent one of the most promising structures to beat the diffraction limit imposed by conventional dielectric optics. Ag nano wires have drawn increasing research attention due to 2D sub-100 nm mode confinement and lower losses as compared with fabricated metal structures. However, rational and versatile integration of Ag nanowires with other active and passive optical components, as well as Ag nanowire based optical routing networks, has yet to be achieved. Here, we demonstrate that SPPs can be excited simply by contacting a silver nanowire with a SnO2 nanoribbon that serves both as an unpolarized light source and a dielectric waveguide. The efficient coupling makes it possible to measure the propagation-distance-dependent waveguide spectra and frequency-dependent propagation length on a single Ag nanowire. Furthermore, we have demonstrated prototypical photonic-plasmonic routing devices, which are essential for incorporating low-loss Ag nanowire waveguides as practical components into high-capacity photonic circuits.

  8. Aluminum Hydroxide

    MedlinePlus

    Aluminum hydroxide is used for the relief of heartburn, sour stomach, and peptic ulcer pain and to ... Aluminum hydroxide comes as a capsule, a tablet, and an oral liquid and suspension. The dose and ...

  9. Magnesium Hydroxide

    MedlinePlus

    Magnesium hydroxide is used on a short-term basis to treat constipation.This medication is sometimes prescribed ... Magnesium hydroxide come as a tablet and liquid to take by mouth. It usually is taken as ...

  10. Nickel hydroxide deposited indium tin oxide electrodes as electrocatalysts for direct oxidation of carbohydrates in alkaline medium

    NASA Astrophysics Data System (ADS)

    Ganesh, V.; Farzana, S.; Berchmans, Sheela

    In this work, the direct electrochemical oxidation of carbohydrates using nickel hydroxide modified indium tin oxide (ITO) electrodes in alkaline medium is demonstrated; suggesting the feasibility of using carbohydrates as a novel fuel in alkaline fuel cells applications. The chosen monosaccharides are namely glucose and fructose; disaccharides such as sucrose and lactose; and sugar acid like ascorbic acid for this study. ITO electrodes are chemically modified using a hexagonal lyotropic liquid crystalline phase template electrodeposition of nickel. Structural morphology, growth, orientation and electrochemical behaviour of Ni deposits are characterized using SEM, XRD, XPS and cyclic voltammetry (CV), respectively. Further electrochemical potential cycling process in alkaline medium is employed to convert these Ni deposits into corresponding nickel hydroxide modified electrodes. These electrodes are used as novel platform to perform the electrocatalytic oxidation of various carbohydrates in alkaline medium. It was found that bare and Ni coated ITO electrodes are inactive towards carbohydrates oxidation. The heterogeneous rate constant values are determined and calculated to be two orders of magnitude higher in the case of template method when compared to non-template technique. The observed effect is attributed to the synergistic effect of higher surface area of these deposits and catalytic ability of Ni(II)/Ni(III) redox couple.

  11. The layered double hydroxide route to Bi-Zn co-doped TiO₂ with high photocatalytic activity under visible light.

    PubMed

    Benalioua, Bahia; Mansour, Meriem; Bentouami, Abdelhadi; Boury, Bruno; Elandaloussi, El Hadj

    2015-05-15

    In this work, a co-doped Bi-Zn-TiO₂ photocatalist is synthesized by an original synthesis route of layered double hydroxide followed by heat treatment at 670 °C. After characterization the photocatalyst efficiency is estimated by the photo-discoloration of an anionic dye (indigo carmine) under visible light and compare to TiO₂-P25 as reference material. In this new photocatalyst, anatase and ZnO wurtzite are the only identified crystalline phase, rutile and Bi₂O₃ being undetected. Moreover, the binding energy of Bi determined (XPS analysis) is different from the one of Bi in Bi₂O₃. Compared to TiO₂-P25, the absorption is red shifted (UV-vis DRS) and the Bi-Zn-TiO₂ photocatalyst showed sorption capacity toward indigo carmine higher than that TiO₂-P25. The kinetics of the photo-discoloration is faster with Bi-Zn-TiO₂ than with TiO₂-P25. Indeed, a complete discoloration is obtained after 70 min and 120 min in the presence of Bi-Zn-TiO₂ and TiO₂-P25 respectively. The identification of the responsible species on photo-discoloration was carried out in the presence of different scavengers. The study showed that the first responsible is h(+) specie with a moderate contribution of superoxide anion radical and a minor contribution of the hydroxyl radical. The material showed high stability after five uses with the same rate of photo-discoloration. PMID:25699677

  12. Memory for object location and route direction in virtual large-scale space.

    PubMed

    Janzen, Gabriele

    2006-03-01

    In everyday life people have to deal with tasks such as finding a novel path to a certain goal location, finding one's way back, finding a short cut, or making a detour. In all of these tasks people acquire route knowledge. For finding the same way back they have to remember locations of objects like buildings and additionally direction changes. In three experiments using recognition tasks as well as conscious and unconscious spatial priming paradigms memory processes underlying wayfinding behaviour were investigated. Participants learned a route through a virtual environment with objects either placed at intersections (i.e., decision points) where another route could be chosen or placed along the route (non-decision points). Analyses indicate first that objects placed at decision points are recognized faster than other objects. Second, they indicate that the direction in which a route is travelled is represented only at locations that are relevant for wayfinding (e.g., decision points). The results point out the efficient way in which memory for object location and memory for route direction interact.

  13. A system for routing arbitrary directed graphs on SIMD architectures

    NASA Technical Reports Server (NTRS)

    Tomboulian, Sherryl

    1987-01-01

    There are many problems which can be described in terms of directed graphs that contain a large number of vertices where simple computations occur using data from connecting vertices. A method is given for parallelizing such problems on an SIMD machine model that is bit-serial and uses only nearest neighbor connections for communication. Each vertex of the graph will be assigned to a processor in the machine. Algorithms are given that will be used to implement movement of data along the arcs of the graph. This architecture and algorithms define a system that is relatively simple to build and can do graph processing. All arcs can be transversed in parallel in time O(T), where T is empirically proportional to the diameter of the interconnection network times the average degree of the graph. Modifying or adding a new arc takes the same time as parallel traversal.

  14. Directing wayfinders with maps: the effects of gender, age, route complexity, and familiarity with the environment.

    PubMed

    Harrell, W A; Bowlby, J W; Hall-Hoffarth, D

    2000-04-01

    The participants were 360 Canadian undergraduates. After receiving written scenarios involving a campus visitor seeking direction to a nearby destination (simple route) or a distant destination (complex route), they drew maps to that destination. The authors varied the visitor's gender, age, and familiarity with campus. They analyzed the content of the students' maps in terms of cardial indicators (compass grid, correct north-south orientation), landmarks, labeled buildings, directional arrows, and supplemental written directions. The men tended to provide more cartographically complete maps than the women, though there were no gender differences in use of landmarks or labeled buildings. The men were significantly more inclined than the women to take visitor characteristics into account, providing more complete maps to visitors navigating complex routes, to newcomers, and to older visitors who were unfamiliar with the campus. The men had more confidence that their maps would successfully lead visitors to their destinations. Route complexity led to greater use of landmarks, labeled buildings, and cardinal indicators. The participants' self-reported familiarity with campus had little effect on their direction giving, except for a greater use of labeled buildings in maps.

  15. Identification of a Specific Maleate Hydratase in the Direct Hydrolysis Route of the Gentisate Pathway.

    PubMed

    Liu, Kun; Xu, Ying; Zhou, Ning-Yi

    2015-09-01

    In contrast to the well-characterized and more common maleylpyruvate isomerization route of the gentisate pathway, the direct hydrolysis route occurs rarely and remains unsolved. In Pseudomonas alcaligenes NCIMB 9867, two gene clusters, xln and hbz, were previously proposed to be involved in gentisate catabolism, and HbzF was characterized as a maleylpyruvate hydrolase converting maleylpyruvate to maleate and pyruvate. However, the complete degradation pathway of gentisate through direct hydrolysis has not been characterized. In this study, we obtained from the NCIMB culture collection a Pseudomonas alcaligenes spontaneous mutant strain that lacked the xln cluster and designated the mutant strain SponMu. The hbz cluster in strain SponMu was resequenced, revealing the correct location of the stop codon for hbzI and identifying a new gene, hbzG. HbzIJ was demonstrated to be a maleate hydratase consisting of large and small subunits, stoichiometrically converting maleate to enantiomerically pure d-malate. HbzG is a glutathione-dependent maleylpyruvate isomerase, indicating the possible presence of two alternative pathways of maleylpyruvate catabolism. However, the hbzF-disrupted mutant could still grow on gentisate, while disruption of hbzG prevented this ability, indicating that the direct hydrolysis route was not a complete pathway in strain SponMu. Subsequently, a d-malate dehydrogenase gene was introduced into the hbzG-disrupted mutant, and the engineered strain was able to grow on gentisate via the direct hydrolysis route. This fills a gap in our understanding of the direct hydrolysis route of the gentisate pathway and provides an explanation for the high yield of d-malate from maleate by this d-malate dehydrogenase-deficient natural mutant.

  16. NICKEL HYDROXIDES

    SciTech Connect

    MCBREEN,J.

    1997-11-01

    Nickel hydroxides have been used as the active material in the positive electrodes of several alkaline batteries for over a century. These materials continue to attract a lot of attention because of the commercial importance of nickel-cadmium and nickel-metal hydride batteries. This review gives a brief overview of the structure of nickel hydroxide battery electrodes and a more detailed review of the solid state chemistry and electrochemistry of the electrode materials. Emphasis is on work done since 1989.

  17. Neighbor-directed histidine N (τ)-alkylation: A route to imidazolium-containing phosphopeptide macrocycles.

    PubMed

    Qian, Wen-Jian; Park, Jung-Eun; Grant, Robert; Lai, Christopher C; Kelley, James A; Yaffe, Michael B; Lee, Kyung S; Burke, Terrence R

    2015-11-01

    Our recently discovered, selective, on-resin route to N(τ)-alkylated imidazolium-containing histidine residues affords new strategies for peptide mimetic design. In this, we demonstrate the use of this chemistry to prepare a series of macrocyclic phosphopeptides, in which imidazolium groups serve as ring-forming junctions. Interestingly, these cationic moieties subsequently serve to charge-mask the phosphoamino acid group that directed their formation. Neighbor-directed histidine N(τ)-alkylation opens the door to new families of phosphopeptidomimetics for use in a range of chemical biology contexts.

  18. Neighbor-directed histidine N(τ) alkylation. A route to imidazolium-containing phosphopeptide macrocycles

    SciTech Connect

    Qian, Wen-Jian; Park, Jung-Eun; Grant, Robert; Lai, Christopher C.; Kelley, James A.; Yaffe, Michael B.; Lee, Kyung S.; Burke, Terrence R.

    2015-07-07

    Our recently discovered, selective, on-resin route to N(τ)-alkylated imidazolium-containing histidine residues affords new strategies for peptide mimetic design. In this, we demonstrate the use of this chemistry to prepare a series of macrocyclic phosphopeptides, in which imidazolium groups serve as ring-forming junctions. These cationic moieties subsequently serve to charge-mask the phosphoamino acid group that directed their formation. Furthermore, neighbor-directed histidine N(τ)-alkylation opens the door to new families of phosphopeptidomimetics for use in a range of chemical biology contexts.

  19. Analysis on vertical directional couplers with long range surface plasmons for multilayer optical routing

    NASA Astrophysics Data System (ADS)

    Alam, B.; Veroli, A.; Benedetti, A.

    2016-08-01

    A structure featuring vertical directional coupling of long-range surface plasmon polaritons between strip waveguides at λ = 1.55 μm is investigated with the aim of producing efficient elements that enable optical multilayer routing for 3D photonics. We have introduced a practical computational method to calculate the interaction on the bent part. This method allows us both to assess the importance of the interaction in the bent part and to control it by a suitable choice of the fabrication parameters that helps also to restrain effects due to fabrication issues. The scheme adopted here allows to reduce the insertion losses compared with other planar and multilayer devices.

  20. A DIRECT ROUTE TO ACYLHYDROQUINONES FROM ALPHA-KETO ACIDS AND ALPHA-CARBOXAMIDO ACIDS. (R825330)

    EPA Science Inventory

    Abstract

    The reaction of quinones with in situ generated acyl- or carboxamido radicals provides a direct route to the synthesis of acylhydroquinones not accessible by the photochemical reaction of quinones with aldehydes.

  1. Drug delivery system for an anticancer agent, chlorogenate-Zn/Al-layered double hydroxide nanohybrid synthesised using direct co-precipitation and ion exchange methods

    SciTech Connect

    Barahuie, Farahnaz; Hussein, Mohd Zobir; Arulselvan, Palanisamy; Fakurazi, Sharida; Zainal, Zulkarnain

    2014-09-15

    A nano-structured drug-inorganic clay hybrid involving an active anticancer compound, which is chlorogenic acid (CA) intercalated into Zn/Al-layered double hydroxide, has been assembled via ion-exchange and co-precipitation methods to form a nanohybrid CZAE (a chlorogenic acid-Zn/Al nanohybrid synthesised using an ion-exchange method) and CZAC (a chlorogenic acid-Zn/Al nanohybrid synthesised using a direct method), respectively. The X-ray diffraction (XRD) results confirmed that the CA-LDH had a hybrid structure in which the anionic chlorogenate is arranged between the interlayers as a horizontal monolayer at 90 and 20° angles from the x axis for CZAE and CZAC, respectively. Both nanohybrids have the properties of mesoporous materials. The high loading percentage of chlorogenic acid (approximately 43.2% for CZAE and 45.3% for CZAC) with basal spacings of 11.7 and 12.6 Å for CZAE and CZAC, respectively, corroborates the successful intercalation of chlorogenic acid into the interlayer gallery of layered double hydroxides. Free chlorogenic acid and the synthesised nanocomposites (CZAE, CZAC) were assessed for their cytotoxicity against various cancer cells. The Fourier transform infrared data supported the formation of both nanohybrids, and a thermal analysis showed that the nanohybrids are more thermally stable than their counterparts. The chlorogenate shows a sustained release, and the release rate of chlorogenate from CZAE and CZAC nanohybrids at pH 7.4 is remarkably lower than that at pH 4.8 due to their different release mechanisms. The release rate of chlorogenate from both nanohybrids can be described as pseudo-second order. The present investigation revealed the potential of the nanohybrids to enhance the in vitro anti-tumour effect of chlorogenic acid in liver and lung cancer cells in vitro. - Highlights: • We intercalated chlorogenic into Zn/Al-layered double hydroxide by ion-exchange and coprecipitation methods. • The two methods gave nanocomposites

  2. Direct coating for layered double hydroxide/4,4'-diaminostilbene-2,2'-disulfonic acid nanocomposite with silica by seeded polymerization technique

    NASA Astrophysics Data System (ADS)

    El-Toni, Ahmed Mohamed; Yin, Shu; Sato, Tsugio

    2004-09-01

    Organic ultraviolet (UV) ray absorbents have been used as sunscreen materials, but may pose a safety problem when used at high concentration. In order to prevent direct contact of organic UV rays absorbent by the human skin, an organic UV absorbent such as 4,4'-diaminostilbene-2,2'-disulfonic acid (DASDSA) was intercalated into Zn 2Al-layered double hydroxide (Zn 2Al-LDHs) by coprecipiation reaction. The problem of deintercalation of organic molecules from LDHs by the anion exchange reaction with carbonate ion could be greatly depressed by forming a protection film of silica on the surface. Zn 2Al-LDH/DASDSA was directly coated with silica by means of a polymerization technique based on the Stöber method. The deintercalation behavior as well as UV-shielding properties were investigated for coated particles.

  3. Horseradish peroxidase immobilization on carbon nanodots/CoFe layered double hydroxides: direct electrochemistry and hydrogen peroxide sensing.

    PubMed

    Wang, Yinling; Wang, Zhangcui; Rui, Yeping; Li, Maoguo

    2015-02-15

    Carbon nanodots and CoFe layered double hydroxide composites (C-Dots/LDHs) were prepared via simply mixing C-Dots and CoFe-LDHs. The as-prepared composites were used for the immobilization of horseradish peroxidase (HRP) on the glass carbon (GC) electrode. The electrochemical behavior of the HRP/C-Dots/LDHs/GC electrode and its application as a H2O2 biosensor were investigated. The results indicated that HRP immobilized by C-Dots/LDHs retained the activity of enzyme and displayed quasi-reversible redox behavior and fast electron transfer with an electron transfer rate constant ks of 8.46 s(-1). Under optimum experimental conditions, the HRP/C-Dots/LDHs/GC electrode displayed good electrocatalytic reduction activity and excellent analytic performance toward H2O2. The H2O2 biosensor showed a linear range of 0.1-23.1 μM (R(2) = 0.9942) with a calculated detection limit of 0.04 μM (S/N = 3). In addition, the biosensor exhibited high sensitivity, good selectivity, acceptable reproducibility and stability. The superior properties of this biosensor are attributed to the synergistic effect of HRP, C-Dots and CoFe-LDHs, which has been proved by investigating their electrochemical response to H2O2. Thus the C-Dots and LDHs composites provide a promising platform for the immobilization of redox enzymes and construction of sensitive biosensors.

  4. CuO nanoparticles encapsulated inside Al-MCM-41 mesoporous materials via direct synthetic route

    PubMed Central

    Huo, Chengli; Ouyang, Jing; Yang, Huaming

    2014-01-01

    Highly ordered aluminum-containing mesoporous silica (Al-MCM-41) was prepared using attapulgite clay mineral as a Si and Al source. Mesoporous complexes embedded with CuO nanoparticles were subsequently prepared using various copper sources and different copper loadings in a direct synthetic route. The resulting CuO/Al-MCM-41 composite possessed p6mm hexagonally symmetry, well-developed mesoporosity, and relatively high BET surface area. In comparison to pure silica, these mesoporous materials embedded with CuO nanoparticles exhibited smaller pore diameter, thicker pore wall, and enhanced thermal stability. Long-range order in the aforementioned samples was observed for copper weight percentages as high as 30%. Furthermore, a significant blue shift of the absorption edge for the samples was observed when compared with that of bulk CuO. H2-TPR measurements showed that the direct-synthesized CuO/Al-MCM-41 exhibited remarkable redox properties compared to the post-synthesized samples, and most of the CuO nanoparticles were encapsulated within the mesoporous structures. The possible interaction between CuO and Al-MCM-41 was also investigated. PMID:24419589

  5. SEPARATION OF PLUTONIUM HYDROXIDE FROM BISMUTH HYDROXIDE

    DOEpatents

    Watt, G.W.

    1958-08-19

    An tmproved method is described for separating plutonium hydroxide from bismuth hydroxide. The end product of the bismuth phosphate processes for the separation amd concentration of plutonium is a inixture of bismuth hydroxide amd plutonium hydroxide. It has been found that these compounds can be advantageously separated by treatment with a reducing agent having a potential sufficient to reduce bismuth hydroxide to metalltc bisinuth but not sufficient to reduce the plutonium present. The resulting mixture of metallic bismuth and plutonium hydroxide can then be separated by treatment with a material which will dissolve plutonium hydroxide but not metallic bismuth. Sodiunn stannite is mentioned as a preferred reducing agent, and dilute nitric acid may be used as the separatory solvent.

  6. Transmission routes of African swine fever virus to domestic pigs: current knowledge and future research directions.

    PubMed

    Guinat, Claire; Gogin, Andrey; Blome, Sandra; Keil, Guenther; Pollin, Reiko; Pfeiffer, Dirk U; Dixon, Linda

    2016-03-12

    African swine fever (ASF) is a major threat to the pig industry in Europe. Since 2007, ASF outbreaks have been ongoing in the Caucasus, Eastern Europe and the Baltic countries, causing severe economic losses for many pig farmers and pork producers. In addition, the number of ASF cases in wild boar populations has dramatically increased over the past few years. Evidence supports direct contact with infectious domestic pigs and wild boars, and consumption of contaminated feed, as the main transmission routes of ASF virus (ASFV) to domestic pigs. However, significant knowledge gaps highlight the urgent need for research to investigate the dynamics of indirect transmission via the environment, the minimal infective doses for contaminated feed ingestion, the probability of effective contacts between infectious wild boars and domestic pigs, the potential for recovered animals to become carriers and a reservoir for transmission, the potential virus persistence within wild boar populations and the influence of human behaviour for the spread of ASFV. This will provide an improved scientific basis to optimise current interventions and develop new tools and strategies to reduce the risk of ASFV transmission to domestic pigs. PMID:26966305

  7. Assessment of air quality in and around a steel industry with direct reduction iron route.

    PubMed

    Jena, Pradip K; Behera, Dillip K; Mishra, C S K; Mohanty, Saswat K

    2011-10-01

    The coal based Direct Reduced Iron (DRI) route for secondary steel production is now a preferred choice in India. Steel making is invariably associated with emission of air pollutants into the environment. Air quality monitoring was carried out in Winter, Summer and Rainy seasons of 2008 in eight monitoring stations in the work zone and five stations in the residential zone of an Integrated Steel Industry located in Orissa state, India. Four air quality parameters i.e. SPM, RSPM, SO2 and NO2 were monitored. Mean SPM and RSPM values were found to be significantly high (p < 0.01) at stations nearer to source in both work zone and residential zone .The highest average SPM and RSPM values in the work zone recorded were 4869 microg/m3 and 1420 microg/m3 and in the residential zone 294 microg/m3 and 198 microg/m3 respectively. No significant difference in the SO2 and NO2 levels was observed between the work and residential zones. In general, the values of air pollutants were highest in Winter followed by Summer and Rainy season. SPM and RSPM values exceeded the National Air Quality Standards (NAAQS) in both the residential and work zones.

  8. Transmission routes of African swine fever virus to domestic pigs: current knowledge and future research directions

    PubMed Central

    Guinat, Claire; Gogin, Andrey; Blome, Sandra; Keil, Guenther; Pollin, Reiko; Pfeiffer, Dirk U.; Dixon, Linda

    2016-01-01

    African swine fever (ASF) is a major threat to the pig industry in Europe. Since 2007, ASF outbreaks have been ongoing in the Caucasus, Eastern Europe and the Baltic countries, causing severe economic losses for many pig farmers and pork producers. In addition, the number of ASF cases in wild boar populations has dramatically increased over the past few years. Evidence supports direct contact with infectious domestic pigs and wild boars, and consumption of contaminated feed, as the main transmission routes of ASF virus (ASFV) to domestic pigs. However, significant knowledge gaps highlight the urgent need for research to investigate the dynamics of indirect transmission via the environment, the minimal infective doses for contaminated feed ingestion, the probability of effective contacts between infectious wild boars and domestic pigs, the potential for recovered animals to become carriers and a reservoir for transmission, the potential virus persistence within wild boar populations and the influence of human behaviour for the spread of ASFV. This will provide an improved scientific basis to optimise current interventions and develop new tools and strategies to reduce the risk of ASFV transmission to domestic pigs. PMID:26966305

  9. Transmission routes of African swine fever virus to domestic pigs: current knowledge and future research directions.

    PubMed

    Guinat, Claire; Gogin, Andrey; Blome, Sandra; Keil, Guenther; Pollin, Reiko; Pfeiffer, Dirk U; Dixon, Linda

    2016-03-12

    African swine fever (ASF) is a major threat to the pig industry in Europe. Since 2007, ASF outbreaks have been ongoing in the Caucasus, Eastern Europe and the Baltic countries, causing severe economic losses for many pig farmers and pork producers. In addition, the number of ASF cases in wild boar populations has dramatically increased over the past few years. Evidence supports direct contact with infectious domestic pigs and wild boars, and consumption of contaminated feed, as the main transmission routes of ASF virus (ASFV) to domestic pigs. However, significant knowledge gaps highlight the urgent need for research to investigate the dynamics of indirect transmission via the environment, the minimal infective doses for contaminated feed ingestion, the probability of effective contacts between infectious wild boars and domestic pigs, the potential for recovered animals to become carriers and a reservoir for transmission, the potential virus persistence within wild boar populations and the influence of human behaviour for the spread of ASFV. This will provide an improved scientific basis to optimise current interventions and develop new tools and strategies to reduce the risk of ASFV transmission to domestic pigs.

  10. Drug delivery system for an anticancer agent, chlorogenate-Zn/Al-layered double hydroxide nanohybrid synthesised using direct co-precipitation and ion exchange methods

    NASA Astrophysics Data System (ADS)

    Barahuie, Farahnaz; Hussein, Mohd Zobir; Arulselvan, Palanisamy; Fakurazi, Sharida; Zainal, Zulkarnain

    2014-09-01

    A nano-structured drug-inorganic clay hybrid involving an active anticancer compound, which is chlorogenic acid (CA) intercalated into Zn/Al-layered double hydroxide, has been assembled via ion-exchange and co-precipitation methods to form a nanohybrid CZAE (a chlorogenic acid-Zn/Al nanohybrid synthesised using an ion-exchange method) and CZAC (a chlorogenic acid-Zn/Al nanohybrid synthesised using a direct method), respectively. The X-ray diffraction (XRD) results confirmed that the CA-LDH had a hybrid structure in which the anionic chlorogenate is arranged between the interlayers as a horizontal monolayer at 90 and 20° angles from the x axis for CZAE and CZAC, respectively. Both nanohybrids have the properties of mesoporous materials. The high loading percentage of chlorogenic acid (approximately 43.2% for CZAE and 45.3% for CZAC) with basal spacings of 11.7 and 12.6 Å for CZAE and CZAC, respectively, corroborates the successful intercalation of chlorogenic acid into the interlayer gallery of layered double hydroxides. Free chlorogenic acid and the synthesised nanocomposites (CZAE, CZAC) were assessed for their cytotoxicity against various cancer cells. The Fourier transform infrared data supported the formation of both nanohybrids, and a thermal analysis showed that the nanohybrids are more thermally stable than their counterparts. The chlorogenate shows a sustained release, and the release rate of chlorogenate from CZAE and CZAC nanohybrids at pH 7.4 is remarkably lower than that at pH 4.8 due to their different release mechanisms. The release rate of chlorogenate from both nanohybrids can be described as pseudo-second order. The present investigation revealed the potential of the nanohybrids to enhance the in vitro anti-tumour effect of chlorogenic acid in liver and lung cancer cells in vitro.

  11. Enhanced butanol production obtained by reinforcing the direct butanol-forming route in Clostridium acetobutylicum.

    PubMed

    Jang, Yu-Sin; Lee, Jin Young; Lee, Joungmin; Park, Jin Hwan; Im, Jung Ae; Eom, Moon-Ho; Lee, Julia; Lee, Sang-Hyun; Song, Hyohak; Cho, Jung-Hee; Seung, Do Young; Lee, Sang Yup

    2012-10-23

    Butanol is an important industrial solvent and advanced biofuel that can be produced by biphasic fermentation by Clostridium acetobutylicum. It has been known that acetate and butyrate first formed during the acidogenic phase are reassimilated to form acetone-butanol-ethanol (cold channel). Butanol can also be formed directly from acetyl-coenzyme A (CoA) through butyryl-CoA (hot channel). However, little is known about the relative contributions of the two butanol-forming pathways. Here we report that the direct butanol-forming pathway is a better channel to optimize for butanol production through metabolic flux and mass balance analyses. Butanol production through the hot channel was maximized by simultaneous disruption of the pta and buk genes, encoding phosphotransacetylase and butyrate kinase, while the adhE1(D485G) gene, encoding a mutated aldehyde/alcohol dehydrogenase, was overexpressed. The ratio of butanol produced through the hot channel to that produced through the cold channel increased from 2.0 in the wild type to 18.8 in the engineered BEKW(pPthlAAD(**)) strain. By reinforcing the direct butanol-forming flux in C. acetobutylicum, 18.9 g/liter of butanol was produced, with a yield of 0.71 mol butanol/mol glucose by batch fermentation, levels which are 160% and 245% higher than those obtained with the wild type. By fed-batch culture of this engineered strain with in situ recovery, 585.3 g of butanol was produced from 1,861.9 g of glucose, with the yield of 0.76 mol butanol/mol glucose and productivity of 1.32 g/liter/h. Studies of two butanol-forming routes and their effects on butanol production in C. acetobutylicum described here will serve as a basis for further metabolic engineering of clostridia aimed toward developing a superior butanol producer. IMPORTANCE Renewable biofuel is one of the answers to solving the energy crisis and climate change problems. Butanol produced naturally by clostridia has superior liquid fuel characteristics and thus has

  12. Combining flow routing modelling and direct velocity measurement for optimal discharge estimation

    NASA Astrophysics Data System (ADS)

    Corato, G.; Moramarco, T.; Tucciarelli, T.

    2011-03-01

    A new procedure is proposed for estimating river discharge hydrographs during flood events, using only water level data measured at a gauged site, as well as 1-D shallow water modelling and sporadic maximum surface flow velocity measurements. During flood, the piezometric level is surmised constant in the vertical plane of the river section, where the top of the banks is always above the river level, and is well represented by the recorded stage hydrograph. The river is modelled along the reach directly located downstream the upstream gauged section, where discharge hydrograph is sought after. For the stability with respect to the topographic error, as well as for the simplicity of the data required to satisfy the boundary conditions, a diffusive hydraulic model is adopted for flow routing. Assigned boundary conditions are: (1) the recorded stage hydrograph at the upstream river site and (2) the zero diffusion condition at the downstream end of the reach. The MAST algorithm is used for the numerical solution of the flow routing problem, which is embedded in the Brent algorithm used for the computation of the optimum Manning coefficient. Based on synthetic tests concerning a broad prismatic channel, the optimal reach length is chosen so that the approximated downstream boundary condition effects on discharge hydrograph assessment at upstream end are negligible. The roughness Manning coefficient is calibrated by using sporadic instantaneous surface velocity measurements during the rising limb of flood that are turned into instantaneous discharges through the solid of velocity estimated by a two-dimensional entropic model. Several historical events, occurring in three gauged sites along the upper Tiber River wherein a reliable rating curve is available, have been used for the validation. The analysis outcomes can be so summarized: (1) criteria adopted for selecting the optimal channel length and based on synthetic tests have been proved reliable by using field data of

  13. Calcium hydroxide poisoning

    MedlinePlus

    Hydrate - calcium; Lime milk; Slaked lime ... Calcium hydroxide ... These products contain calcium hydroxide: Cement Limewater Many industrial solvents and cleaners (hundreds to thousands of construction products, flooring strippers, brick cleaners, cement ...

  14. Developing a Direct Search Algorithm for Solving the Capacitated Open Vehicle Routing Problem

    NASA Astrophysics Data System (ADS)

    Simbolon, Hotman

    2011-06-01

    In open vehicle routing problems, the vehicles are not required to return to the depot after completing service. In this paper, we present the first exact optimization algorithm for the open version of the well-known capacitated vehicle routing problem (CVRP). The strategy of releasing nonbasic variables from their bounds, combined with the "active constraint" method and the notion of superbasics, has been developed for efficiently requirements; this strategy is used to force the appropriate non-integer basic variables to move to their neighborhood integer points. A study of criteria for choosing a nonbasic variable to work with in the integerizing strategy has also been made.

  15. Testing the dual-route model of perceived gaze direction: Linear combination of eye and head cues.

    PubMed

    Otsuka, Yumiko; Mareschal, Isabelle; Clifford, Colin W G

    2016-06-01

    We have recently proposed a dual-route model of the effect of head orientation on perceived gaze direction (Otsuka, Mareschal, Calder, & Clifford, 2014; Otsuka, Mareschal, & Clifford, 2015), which computes perceived gaze direction as a linear combination of eye orientation and head orientation. By parametrically manipulating eye orientation and head orientation, we tested the adequacy of a linear model to account for the effect of horizontal head orientation on perceived direction of gaze. Here, participants adjusted an on-screen pointer toward the perceived gaze direction in two image conditions: Normal condition and Wollaston condition. Images in the Normal condition included a change in the visible part of the eye along with the change in head orientation, while images in the Wollaston condition were manipulated to have identical eye regions across head orientations. Multiple regression analysis with explanatory variables of eye orientation and head orientation revealed that linear models account for most of the variance both in the Normal condition and in the Wollaston condition. Further, we found no evidence that the model with a nonlinear term explains significantly more variance. Thus, the current study supports the dual-route model that computes the perceived gaze direction as a linear combination of eye orientation and head orientation. PMID:27281465

  16. Molten Hydroxide Trapping Process for Radioiodine

    SciTech Connect

    Trowbridge, L.D.

    2003-01-28

    A molten hydroxide trapping process has been considered for removing radioiodine species from off-gas streams whereby iodine is reacted directly with molten hydroxides such as NaOH or KOH. The resulting product is the corresponding iodide, which can be separated by simple cooling of the molten mixture to grow the iodide primary phase once the mixture reaches 70-80 mol% in the iodide component. Thermodynamic analysis indicates that such a chemical process is highly favorable. Experimental testing of the trapping process using molecular iodine showed trapping of up to 96% of the volatile iodine. The trapping efficiency was dependent on operational parameters such as temperature and gas-melt contact efficiency, and higher efficiencies are expected as the process is further developed. While an iodide phase could be effectively isolated by slow cooling of a molten iodide-hydroxide mixture, the persistent appearance of hydroxide indicated that an appreciable solubility of hydroxide occurred in the iodide phase.

  17. A Dicer-Independent Route for Biogenesis of siRNAs that Direct DNA Methylation in Arabidopsis.

    PubMed

    Ye, Ruiqiang; Chen, Zulong; Lian, Bi; Rowley, M Jordan; Xia, Ning; Chai, Jijie; Li, Yan; He, Xin-Jian; Wierzbicki, Andrzej T; Qi, Yijun

    2016-01-21

    DNA methylation directed by 24-nucleotide (nt) small interfering RNAs (siRNAs) plays critical roles in gene regulation and transposon silencing in Arabidopsis. 24-nt siRNAs are known to be processed from double-stranded RNAs by Dicer-like 3 (DCL3) and loaded into the effector Argonaute 4 (AGO4). Here we report a distinct class of siRNAs independent of DCLs (sidRNAs). sidRNAs are present as ladders of ∼ 20-60 nt in length, often having the same 5' ends but differing in 3' ends by 1-nt steps. We further show that sidRNAs are associated with AGO4 and capable of directing DNA methylation. Finally we show that sidRNA production depends on distributive 3'-5' exonucleases. Our findings suggest an alternative route for siRNA biogenesis. Precursor transcripts are bound by AGO4 and subsequently subjected to 3'-5' exonucleolytic trimming for maturation. We propose that sidRNAs generated through this route are the initial triggers of de novo DNA methylation. PMID:26711010

  18. Both visual and idiothetic cues contribute to head direction cell stability during navigation along complex routes

    PubMed Central

    Yoder, Ryan M.; Clark, Benjamin J.; Brown, Joel E.; Lamia, Mignon V.; Valerio, Stephane; Shinder, Michael E.

    2011-01-01

    Successful navigation requires a constantly updated neural representation of directional heading, which is conveyed by head direction (HD) cells. The HD signal is predominantly controlled by visual landmarks, but when familiar landmarks are unavailable, self-motion cues are able to control the HD signal via path integration. Previous studies of the relationship between HD cell activity and path integration have been limited to two or more arenas located in the same room, a drawback for interpretation because the same visual cues may have been perceptible across arenas. To address this issue, we tested the relationship between HD cell activity and path integration by recording HD cells while rats navigated within a 14-unit T-maze and in a multiroom maze that consisted of unique arenas that were located in different rooms but connected by a passageway. In the 14-unit T-maze, the HD signal remained relatively stable between the start and goal boxes, with the preferred firing directions usually shifting <45° during maze traversal. In the multiroom maze in light, the preferred firing directions also remained relatively constant between rooms, but with greater variability than in the 14-unit maze. In darkness, HD cell preferred firing directions showed marginally more variability between rooms than in the lighted condition. Overall, the results indicate that self-motion cues are capable of maintaining the HD cell signal in the absence of familiar visual cues, although there are limits to its accuracy. In addition, visual information, even when unfamiliar, can increase the precision of directional perception. PMID:21451060

  19. Analysis of Contents, Contributors, and Research Directions: Mapping Publication Routes in the Journal

    ERIC Educational Resources Information Center

    English, Leona; D'souza, Mario; Chartrand, Leon

    2005-01-01

    A content analysis of the journal Religious Education: An Interfaith Journal of Spirituality, Growth and Transformation was conducted for a 10-year period between 1993?2002 (Volume 88, 1?Volume 97, 4). A total of 325 articles (277 authors) were analyzed into 3 primary research directions (theoretical, qualitative, and quantitative). Author…

  20. Isotopic and molecular fractionation in combustion; three routes to molecular marker validation, including direct molecular 'dating' (GC/AMS)

    NASA Astrophysics Data System (ADS)

    Currie, L. A.; Klouda, G. A.; Benner, B. A.; Garrity, K.; Eglinton, T. I.

    The identification of unique isotopic, elemental, and molecular markers for sources of combustion aerosol has growing practical importance because of the potential effects of fine particle aerosol on health, visibility and global climate. It is urgent, therefore, that substantial efforts be directed toward the validation of assumptions involving the use of such tracers for source apportionment. We describe here three independent routes toward carbonaceous aerosol molecular marker identification and validation: (1) tracer regression and multivariate statistical techniques applied to field measurements of mixed source, carbonaceous aerosols; (2) a new development in aerosol 14C metrology: direct, pure compound accelerator mass spectrometry (AMS) by off-line GC/AMS ('molecular dating'); and (3) direct observation of isotopic and molecular source emissions during controlled laboratory combustion of specific fuels. Findings from the combined studies include: independent support for benzo( ghi)perylene as a motor vehicle tracer from the first (statistical) and second (direct 'dating') studies; a new indication, from the third (controlled combustion) study, of a relation between 13C isotopic fractionation and PAH molecular fractionation, also linked with fuel and stage of combustion; and quantitative data showing the influence of both fuel type and combustion conditions on the yields of such species as elemental carbon and PAH, reinforcing the importance of exercising caution when applying presumed conservative elemental or organic tracers to fossil or biomass burning field data as in the first study.

  1. Direction based Hazard Routing Protocol (DHRP) for disseminating road hazard information using road side infrastructures in VANETs.

    PubMed

    Berlin, M A; Anand, Sheila

    2014-01-01

    This paper presents Direction based Hazard Routing Protocol (DHRP) for disseminating information about fixed road hazards such as road blocks, tree fall, boulders on road, snow pile up, landslide, road maintenance work and other obstacles to the vehicles approaching the hazardous location. The proposed work focuses on dissemination of hazard messages on highways with sparse traffic. The vehicle coming across the hazard would report the presence of the hazard. It is proposed to use Road Side fixed infrastructure Units for reliable and timely delivery of hazard messages to vehicles. The vehicles can then take appropriate safety action to avoid the hazardous location. The proposed protocol has been implemented and tested using SUMO simulator to generate road traffic and NS 2.33 network simulator to analyze the performance of DHRP. The performance of the proposed protocol was also compared with simple flooding protocol and the results are presented.

  2. Direction based Hazard Routing Protocol (DHRP) for disseminating road hazard information using road side infrastructures in VANETs.

    PubMed

    Berlin, M A; Anand, Sheila

    2014-01-01

    This paper presents Direction based Hazard Routing Protocol (DHRP) for disseminating information about fixed road hazards such as road blocks, tree fall, boulders on road, snow pile up, landslide, road maintenance work and other obstacles to the vehicles approaching the hazardous location. The proposed work focuses on dissemination of hazard messages on highways with sparse traffic. The vehicle coming across the hazard would report the presence of the hazard. It is proposed to use Road Side fixed infrastructure Units for reliable and timely delivery of hazard messages to vehicles. The vehicles can then take appropriate safety action to avoid the hazardous location. The proposed protocol has been implemented and tested using SUMO simulator to generate road traffic and NS 2.33 network simulator to analyze the performance of DHRP. The performance of the proposed protocol was also compared with simple flooding protocol and the results are presented. PMID:24834371

  3. Direct Acoustic Stimulation at the Lateral Canal: An Alternative Route to the Inner Ear?

    PubMed Central

    Walraevens, Joris; Desloovere, Christian; Wouters, Jan; Gérard, Jean-Marc

    2016-01-01

    Severe to profound mixed hearing loss is associated with hearing rehabilitation difficulties. Recently, promising results for speech understanding were obtained with a direct acoustic cochlear implant (DACI). The surgical implantation of a DACI with standard coupling through a stapedotomy can however be regarded as challenging. Therefore, in this experimental study, the feasibility of direct acoustic stimulation was investigated at an anatomically and surgically more accessible inner ear site. DACI stimulation of the intact, blue-lined and opened lateral semicircular canal (LC) was investigated and compared with standard oval window (OW) coupling. Additionally, stapes footplate fixation was induced. Round window (RW) velocity, as a measure of the performance of the device and its coupling efficiency, was determined in fresh-frozen human cadaver heads. Using single point laser Doppler vibrometry, RW velocity could reliably be measured in low and middle frequency range, and equivalent sound pressure level (LE) output was calculated. Results for the different conditions obtained in five heads were analyzed in subsequent frequency ranges. Comparing the difference in RW membrane velocity showed higher LE in the LC opened condition [mean: 103 equivalent dB SPL], than in LC intact or blue-lined conditions [63 and 74 equivalent dB SPL, respectively]. No difference was observed between the LC opened and the standard OW condition. Inducing stapes fixation, however, led to a difference in the low frequency range of LE compared to LC opened. In conclusion, this feasibility study showed promising results for direct acoustic stimulation at this specific anatomically and surgically more accessible inner ear site. Future studies are needed to address the impact of LC stimulation on cochlear micromechanics and on the vestibular system like dizziness and risks of hearing loss. PMID:27500399

  4. A "Green" route to adipic acid: direct oxidation of cyclohexenes with 30 percent hydrogen peroxide

    PubMed

    Sato; Aoki; Noyori

    1998-09-11

    Currently, the industrial production of adipic acid uses nitric acid oxidation of cyclohexanol or a cyclohexanol/cyclohexanone mixture. The nitrous oxide emission from this process measurably contributes to global warming and ozone depletion. Therefore, the development of an adipic acid production process that is less damaging to the environment is an important subject in chemical research. Cyclohexene can now be oxidized directly to colorless crystalline adipic acid with aqueous 30 percent hydrogen peroxide under organic solvent- and halide-free conditions, which could provide an ideal solution to this serious problem.

  5. A short scalable route to (-)-α-kainic acid using Pt-catalyzed direct allylic amination.

    PubMed

    Zhang, Ming; Watanabe, Kenji; Tsukamoto, Masafumi; Shibuya, Ryozo; Morimoto, Hiroyuki; Ohshima, Takashi

    2015-03-01

    An increased supply of scarce or inaccessible natural products is essential for the development of more sophisticated pharmaceutical agents and biological tools, and thus the development of atom-economical, step-economical and scalable processes to access these natural products is in high demand. Herein we report the development of a short, scalable total synthesis of (-)-α-kainic acid, a useful compound in neuropharmacology that is, however, limited in supply from natural resources. The synthesis features sequential platinum-catalyzed direct allylic aminations and thermal ene-cyclization, enabling the gram-scale synthesis of (-)-α-kainic acid in six steps and 34% overall yield. PMID:25604395

  6. Impact of semantic similarity in novel associations: Direct and indirect routes to action.

    PubMed

    Macdonald, Scott N; Richards, Eric D; Desmarais, Geneviève

    2016-01-01

    Actions produced in response to familiar objects are predominantly mediated by the visual structure of objects, and less so by their semantic associations. Choosing an action in response to an object tends to be faster than choosing the object's name, leading to the suggestion that there are direct links between the visual representations of objects and their actions. The relative contribution of semantics, however, is unclear when actions are produced in response to novel objects. To investigate the role of semantics when object-action associations are novel, we had participants learn to use and name novel objects and rehearse the object, action, and name associations over one week. Each object-action pair was associated with a label that was either semantically similar or semantically distinct. We found that semantic similarity only affected action and name production when the object associations were novel, suggesting that semantic information is recruited when actions are produced in response to novel objects. We also observed that the advantage to producing an action was absent when associations were novel, suggesting that practice is necessary for these direct links to develop. PMID:26704564

  7. Potassium hydroxide poisoning

    MedlinePlus

    This article discusses poisoning from swallowing or touching potassium hydroxide or products that contain this chemical. This article is for information only. Do NOT use it to treat or manage an actual poison exposure. If ...

  8. A direct electrochemical route from ilmenite to hydrogen-storage ferrotitanium alloys.

    PubMed

    Ma, Meng; Wang, Dihua; Hu, Xiaohong; Jin, Xianbo; Chen, George Z

    2006-06-23

    An unrecognised but predictable need for a hydrogen-supported society is tens or even hundreds of million tonnes of hydrogen-storage materials, and thus challenges existing technologies in terms of resource and economical realities. Ilmenite is an abundant mineral, and ferrotitanium alloys are among the earliest known hydrogen-storage materials. At present, industrial production of ferrotitanium alloys goes through separate extraction of individual metals, followed by a multistep arc-melting process. In particular, the extraction of titanium from ilmenite is highly energy intensive and tedious, accounting for titanium's high market price and restricted uses. This article reports the electrochemical synthesis of various ferrotitanium alloy powders directly from solid ilmenite in molten calcium chloride. More importantly, it demonstrates, for the first time, that such produced alloy powders can be used without further treatment for hydrogen storage and perform comparably with or better than similar products by means of other methods, but cost just a fraction.

  9. Solar silicon from directional solidification of MG silicon produced via the silicon carbide route

    NASA Technical Reports Server (NTRS)

    Rustioni, M.; Margadonna, D.; Pirazzi, R.; Pizzini, S.

    1986-01-01

    A process of metallurgical grade (MG) silicon production is presented which appears particularly suitable for photovoltaic (PV) applications. The MG silicon is prepared in a 240 KVA, three electrode submerged arc furnace, starting from high grade quartz and high purity silicon carbide. The silicon smelted from the arc furnace was shown to be sufficiently pure to be directionally solidified to 10 to 15 kg. After grinding and acid leaching, had a material yield larger than 90%. With a MG silicon feedstock containing 3 ppmw B, 290 ppmw Fe, 190 ppmw Ti, and 170 ppmw Al, blended with 50% of off grade electronic grade (EG) silicon to reconduct the boron content to a concentration acceptable for solar cell fabrication, the 99% of deep level impurities were concentrated in the last 5% of the ingot. Quite remarkably this material has OCV values higher tham 540 mV and no appreciable shorts due to SiC particles.

  10. Gas-phase hydrolysis of triplet SO2: A possible direct route to atmospheric acid formation.

    PubMed

    Donaldson, D James; Kroll, Jay A; Vaida, Veronica

    2016-07-15

    Sulfur chemistry is of great interest to the atmospheric chemistry of several planets. In the presence of water, oxidized sulfur can lead to new particle formation, influencing climate in significant ways. Observations of sulfur compounds in planetary atmospheres when compared with model results suggest that there are missing chemical mechanisms. Here we propose a novel mechanism for the formation of sulfurous acid, which may act as a seed for new particle formation. In this proposed mechanism, the lowest triplet state of SO2 ((3)B1), which may be accessed by near-UV solar excitation of SO2 to its excited (1)B1 state followed by rapid intersystem crossing, reacts directly with water to form H2SO3 in the gas phase. For ground state SO2, this reaction is endothermic and has a very high activation barrier; our quantum chemical calculations point to a facile reaction being possible in the triplet state of SO2. This hygroscopic H2SO3 molecule may act as a condensation nucleus for water, giving rise to facile new particle formation (NPF).

  11. Gas-phase hydrolysis of triplet SO2: A possible direct route to atmospheric acid formation

    NASA Astrophysics Data System (ADS)

    Donaldson, D. James; Kroll, Jay A.; Vaida, Veronica

    2016-07-01

    Sulfur chemistry is of great interest to the atmospheric chemistry of several planets. In the presence of water, oxidized sulfur can lead to new particle formation, influencing climate in significant ways. Observations of sulfur compounds in planetary atmospheres when compared with model results suggest that there are missing chemical mechanisms. Here we propose a novel mechanism for the formation of sulfurous acid, which may act as a seed for new particle formation. In this proposed mechanism, the lowest triplet state of SO2 (3B1), which may be accessed by near-UV solar excitation of SO2 to its excited 1B1 state followed by rapid intersystem crossing, reacts directly with water to form H2SO3 in the gas phase. For ground state SO2, this reaction is endothermic and has a very high activation barrier; our quantum chemical calculations point to a facile reaction being possible in the triplet state of SO2. This hygroscopic H2SO3 molecule may act as a condensation nucleus for water, giving rise to facile new particle formation (NPF).

  12. Gas-phase hydrolysis of triplet SO2: A possible direct route to atmospheric acid formation

    PubMed Central

    Donaldson, D. James; Kroll, Jay A.; Vaida, Veronica

    2016-01-01

    Sulfur chemistry is of great interest to the atmospheric chemistry of several planets. In the presence of water, oxidized sulfur can lead to new particle formation, influencing climate in significant ways. Observations of sulfur compounds in planetary atmospheres when compared with model results suggest that there are missing chemical mechanisms. Here we propose a novel mechanism for the formation of sulfurous acid, which may act as a seed for new particle formation. In this proposed mechanism, the lowest triplet state of SO2 (3B1), which may be accessed by near-UV solar excitation of SO2 to its excited 1B1 state followed by rapid intersystem crossing, reacts directly with water to form H2SO3 in the gas phase. For ground state SO2, this reaction is endothermic and has a very high activation barrier; our quantum chemical calculations point to a facile reaction being possible in the triplet state of SO2. This hygroscopic H2SO3 molecule may act as a condensation nucleus for water, giving rise to facile new particle formation (NPF). PMID:27417675

  13. Overview and extensions of a system for routing directed graphs on SIMD architectures

    NASA Technical Reports Server (NTRS)

    Tomboulian, Sherryl

    1988-01-01

    Many problems can be described in terms of directed graphs that contain a large number of vertices where simple computations occur using data from adjacent vertices. A method is given for parallelizing such problems on an SIMD machine model that uses only nearest neighbor connections for communication, and has no facility for local indirect addressing. Each vertex of the graph will be assigned to a processor in the machine. Rules for a labeling are introduced that support the use of a simple algorithm for movement of data along the edges of the graph. Additional algorithms are defined for addition and deletion of edges. Modifying or adding a new edge takes the same time as parallel traversal. This combination of architecture and algorithms defines a system that is relatively simple to build and can do fast graph processing. All edges can be traversed in parallel in time O(T), where T is empirically proportional to the average path length in the embedding times the average degree of the graph. Additionally, researchers present an extension to the above method which allows for enhanced performance by allowing some broadcasting capabilities.

  14. Gas-phase hydrolysis of triplet SO2: A possible direct route to atmospheric acid formation.

    PubMed

    Donaldson, D James; Kroll, Jay A; Vaida, Veronica

    2016-01-01

    Sulfur chemistry is of great interest to the atmospheric chemistry of several planets. In the presence of water, oxidized sulfur can lead to new particle formation, influencing climate in significant ways. Observations of sulfur compounds in planetary atmospheres when compared with model results suggest that there are missing chemical mechanisms. Here we propose a novel mechanism for the formation of sulfurous acid, which may act as a seed for new particle formation. In this proposed mechanism, the lowest triplet state of SO2 ((3)B1), which may be accessed by near-UV solar excitation of SO2 to its excited (1)B1 state followed by rapid intersystem crossing, reacts directly with water to form H2SO3 in the gas phase. For ground state SO2, this reaction is endothermic and has a very high activation barrier; our quantum chemical calculations point to a facile reaction being possible in the triplet state of SO2. This hygroscopic H2SO3 molecule may act as a condensation nucleus for water, giving rise to facile new particle formation (NPF). PMID:27417675

  15. Nano-Thermal Effect: A Direct Route for Fast Molecular Recognition of Energetic Materials

    SciTech Connect

    Senesac, Larry R; Yi, Dechang; Greve, Anders; Hales, Jan; Davis, Zachary; Nicholson, Don M; Boisen, Anja; Thundat, Thomas George

    2009-01-01

    Although micromechanical sensors enable chemical vapor sensing with unprecedented sensitivity using variations in mass and stress, obtaining chemical selectivity using the micromechanical response still remains as a crucial challenge. Chemoselectivity in vapor detection using immobilized selective layers that rely on weak chemical interactions provides only partial selectivity. Here we show that the very low thermal mass of micromechanical sensors can be used to produce unique responses that can be used for achieving chemical selectivity without losing sensitivity or reversibility. We demonstrate that this method is capable of differentiating explosive vapors from nonexplosives and is additionally capable of differentiating individual explosive vapors such as trinitrotoluene, pentaerythritol tetranitrate, and cyclotrimethylenetrinitromine. This method, based on a microfabricated bridge with a programmable heating rate, produces unique and reproducible thermal response patterns within 50 ms that are characteristic to classes of adsorbed explosive molecules. We demonstrate that this micro-differential thermal analysis technique can selectively detect explosives, providing a method for fast direct detection with a limit of detection of 600 x 10{sup -12} g.

  16. 21 CFR 184.1139 - Ammonium hydroxide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... ingredient as generally recognized as safe (GRAS) as a direct human food ingredient is based upon the... water additive complying with § 173.310 of this chapter. (2) The ingredient is used in food at levels... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Ammonium hydroxide. 184.1139 Section 184.1139...

  17. 21 CFR 184.1139 - Ammonium hydroxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... ingredient as generally recognized as safe (GRAS) as a direct human food ingredient is based upon the... water additive complying with § 173.310 of this chapter. (2) The ingredient is used in food at levels... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Ammonium hydroxide. 184.1139 Section 184.1139...

  18. 21 CFR 184.1139 - Ammonium hydroxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... ingredient as generally recognized as safe (GRAS) as a direct human food ingredient is based upon the... water additive complying with § 173.310 of this chapter. (2) The ingredient is used in food at levels... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Ammonium hydroxide. 184.1139 Section 184.1139...

  19. 21 CFR 184.1139 - Ammonium hydroxide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... ingredient as generally recognized as safe (GRAS) as a direct human food ingredient is based upon the... water additive complying with § 173.310 of this chapter. (2) The ingredient is used in food at levels... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ammonium hydroxide. 184.1139 Section 184.1139...

  20. Hydroxide-catalyzed bonding

    NASA Technical Reports Server (NTRS)

    Gwo, Dz-Hung (Inventor)

    2003-01-01

    A method of bonding substrates by hydroxide-catalyzed hydration/dehydration involves applying a bonding material to at least one surface to be bonded, and placing the at least one surface sufficiently close to another surface such that a bonding interface is formed between them. A bonding material of the invention comprises a source of hydroxide ions, and may optionally include a silicate component, a particulate filling material, and a property-modifying component. Bonding methods of the invention reliably and reproducibly provide bonds which are strong and precise, and which may be tailored according to a wide range of possible applications. Possible applications for bonding materials of the invention include: forming composite materials, coating substrates, forming laminate structures, assembly of precision optical components, and preparing objects of defined geometry and composition. Bonding materials and methods of preparing the same are also disclosed.

  1. Nickel hydroxide electrode. 3: Thermogravimetric investigations of nickel (II) hydroxides

    NASA Technical Reports Server (NTRS)

    Dennstedt, W.; Loeser, W.

    1982-01-01

    Water contained in Ni hydroxide influences its electrochemical reactivity. The water content of alpha and beta Ni hydroxides is different with respect to the amount and bond strength. Thermogravimetric experiments show that the water of the beta Ni hydroxides exceeding the stoichiometric composition is completely removed at 160 deg. The water contained in the interlayers of the beta hydroxide, however, is removed only at higher temperatures, together with the water originating from the decomposition of the hydroxide. These differences are attributed to the formation of II bonds within the interlayers and between interlayers and adjacent main layers. An attempt is made to explain the relations between water content and the oxidizability of the Ni hydroxides.

  2. Mechanically stable, hierarchically porous Cu3(btc)2 (HKUST-1) monoliths via direct conversion of copper(II) hydroxide-based monoliths.

    PubMed

    Moitra, Nirmalya; Fukumoto, Shotaro; Reboul, Julien; Sumida, Kenji; Zhu, Yang; Nakanishi, Kazuki; Furukawa, Shuhei; Kitagawa, Susumu; Kanamori, Kazuyoshi

    2015-02-28

    The synthesis of highly crystalline macro-meso-microporous monolithic Cu3(btc)2 (HKUST-1; btc(3-) = benzene-1,3,5-tricarboxylate) is demonstrated by direct conversion of Cu(OH)2-based monoliths while preserving the characteristic macroporous structure. The high mechanical strength of the monoliths is promising for possible applications to continuous flow reactors. PMID:25572361

  3. Protective immune-response of aluminium hydroxide gel adjuvanted phage lysate of Brucella abortus S19 in mice against direct virulent challenge with B. abortus 544.

    PubMed

    Jain, Lata; Rawat, Mayank; Prajapati, Awadhesh; Tiwari, Ashok Kumar; Kumar, Bablu; Chaturvedi, V K; Saxena, H M; Ramakrishnan, Sarvanan; Kumar, Jatin; Kerketta, Priscilla

    2015-09-01

    The prophylactic efficacies of plain and alum adsorbed lysate were evaluated by direct virulent challenge in mice model. A recently isolated brucellaphage 'ϕLd' was used for generation of lysates. Twenty four h incubated Brucella abortus S19 broth cultures standardized to contain approximately 10(8) CFU/ml were found suitable for generation of lysates. Three lysate batches produced through separate cycles did not show any significant variation with respect to protein and polysaccharide contents, endotoxin level and phage counts, indicating that compositionally stable lysate preparations can be generated through an optimized production process. Three polypeptides of ∼16, 19 and 23 kDa could be identified as immuno-dominant antigens of the lysate which induced both humoral and cell-mediated immune responses in a dose dependent manner. Results of efficacy evaluation trial confirmed dose-dependent protective potencies of lysate preparation. The lysate with an antigenic dose of 0.52 μg protein and 60 μg CHO adsorbed on aluminium gel (0.1 percent aluminium concentration) exhibited the highest protective potency which was greater than that induced by standard S19 vaccine. Phage lysate methodology provides a very viable option through which an improved immunizing preparation with all desirable traits can be developed against brucellosis, and integrated with immunization programmes in a more efficient manner.

  4. Computer Routing.

    ERIC Educational Resources Information Center

    Malone, Roger

    1991-01-01

    Computerized bus-routing systems plot the most efficient routes, cut the time it takes to draw routes, and generate reports quickly and accurately. However, school districts often underestimate the amount of work necessary to get information into the computer database. (MLF)

  5. Advances in aluminum hydroxide-based adjuvant research and its mechanism.

    PubMed

    He, Peng; Zou, Yening; Hu, Zhongyu

    2015-01-01

    In the past few decades, hundreds of materials have been tried as adjuvant; however, only aluminum-based adjuvants continue to be used widely in the world. Aluminum hydroxide, aluminum phosphate and alum constitute the main forms of aluminum used as adjuvants. Among these, aluminum hydroxide is the most commonly used chemical as adjuvant. In spite of its wide spread use, surprisingly, the mechanism of how aluminum hydroxide-based adjuvants exert their beneficial effects is still not fully understood. Current explanations for the mode of action of aluminum hydroxide-based adjuvants include, among others, the repository effect, pro-phagocytic effect, and activation of the pro-inflammatory NLRP3 pathway. These collectively galvanize innate as well as acquired immune responses and activate the complement system. Factors that have a profound influence on responses evoked by aluminum hydroxide-based adjuvant applications include adsorption rate, strength of the adsorption, size and uniformity of aluminum hydroxide particles, dosage of adjuvant, and the nature of antigens. Although vaccines containing aluminum hydroxide-based adjuvants are beneficial, sometimes they cause adverse reactions. Further, these vaccines cannot be stored frozen. Until recently, aluminum hydroxide-based adjuvants were known to preferentially prime Th2-type immune responses. However, results of more recent studies show that depending on the vaccination route, aluminum hydroxide-based adjuvants can enhance both Th1 as well as Th2 cellular responses. Advances in systems biology have opened up new avenues for studying mechanisms of aluminum hydroxide-based adjuvants. These will assist in scaling new frontiers in aluminum hydroxide-based adjuvant research that include improvement of formulations, use of nanoparticles of aluminum hydroxide and development of composite adjuvants. PMID:25692535

  6. Advances in aluminum hydroxide-based adjuvant research and its mechanism

    PubMed Central

    He, Peng; Zou, Yening; Hu, Zhongyu

    2015-01-01

    In the past few decades, hundreds of materials have been tried as adjuvant; however, only aluminum-based adjuvants continue to be used widely in the world. Aluminum hydroxide, aluminum phosphate and alum constitute the main forms of aluminum used as adjuvants. Among these, aluminum hydroxide is the most commonly used chemical as adjuvant. In spite of its wide spread use, surprisingly, the mechanism of how aluminum hydroxide-based adjuvants exert their beneficial effects is still not fully understood. Current explanations for the mode of action of aluminum hydroxide-based adjuvants include, among others, the repository effect, pro-phagocytic effect, and activation of the pro-inflammatory NLRP3 pathway. These collectively galvanize innate as well as acquired immune responses and activate the complement system. Factors that have a profound influence on responses evoked by aluminum hydroxide-based adjuvant applications include adsorption rate, strength of the adsorption, size and uniformity of aluminum hydroxide particles, dosage of adjuvant, and the nature of antigens. Although vaccines containing aluminum hydroxide-based adjuvants are beneficial, sometimes they cause adverse reactions. Further, these vaccines cannot be stored frozen. Until recently, aluminum hydroxide-based adjuvants were known to preferentially prime Th2-type immune responses. However, results of more recent studies show that depending on the vaccination route, aluminum hydroxide-based adjuvants can enhance both Th1 as well as Th2 cellular responses. Advances in systems biology have opened up new avenues for studying mechanisms of aluminum hydroxide-based adjuvants. These will assist in scaling new frontiers in aluminum hydroxide-based adjuvant research that include improvement of formulations, use of nanoparticles of aluminum hydroxide and development of composite adjuvants. PMID:25692535

  7. Acrylate intercalation and in situ polymerization in iron-, cobalt-, or manganese-substituted nickel hydroxides.

    PubMed

    Vaysse, C; Guerlou-Demourgues, L; Duguet, E; Delmas, C

    2003-07-28

    A chimie douce route based on successive redox and exchange reactions has allowed us to prepare new hybrid organic-inorganic materials, composed of polyacrylate macromolecules intercalated into layered double hydroxides (LDHs), deriving from Ni(OH)(2). Monomer intercalation and in situ polymerization mechanisms have appeared to be strongly dependent upon the nature of the substituting cation in the slabs. In the case of iron-based LDHs, a phase containing acrylate monomeric intercalates has been isolated and identified by X-ray diffraction and infrared spectroscopy. Second, interslab free-radical polymerization of acrylate anions has been successfully initiated using potassium persulfate. In cobalt- or manganese-based LDHs, one-step polymerization has been observed, leading directly to a material containing polyacrylate intercalate. PMID:12870945

  8. Surfactant-directed synthesis of mesoporous films made single-step by a tandem photosol-gel/photocalcination route

    SciTech Connect

    De Paz-Simon, Héloïse; Chemtob, Abraham Croutxé-Barghorn, Céline; Rigolet, Séverinne; Michelin, Laure; Vidal, Loïc; Lebeau, Bénédicte

    2014-11-01

    In view of their technological impact in materials chemistry, a simplified and more efficient synthetic route to mesoporous films is highly sought. We report, herein, a smart UV-mediated approach coupling in a one-stage process sol-gel photopolymerization and photoinduced template decomposition/ablation to making mesoporous silica films. Performed at room temperature with a solvent-free solution of silicate precursor and amphiphilic poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) block copolymer, the synthesis relies on photoacid generation to induce the fast formation (≈10 min) of mesostructured silica/surfactant domains. Continuation of UV exposure for three additional hours enables subsequent and complete photodegradation of the polyether copolymer, resulting in ordered or disordered mesoporous silica film. One of the most attractive features is that the one-step procedure relies on a continuous illumination provided by the same conventional medium-pressure Hg-Xe arc lamp equipped with a 254 nm reflector to enhance the emission of energetic photons <300 nm. In addition to X-ray diffraction and transmission electron microscopy, time-resolved Fourier transform infrared spectroscopy has proved to be a powerful in situ technique to probe the different chemical transformations accompanying irradiation. Photocalcination strengthens the inorganic network, while allowing to preserve a higher fraction of residual silanol groups compared with thermal calcination. A polyether chain degradation mechanism based on oxygen reactive species-mediated photo-oxidation is proposed.

  9. Surface modification of amorphous substrates by disulfide derivatives: A photo-assisted route to direct functionalization of chalcogenide glasses

    NASA Astrophysics Data System (ADS)

    Amalric, Julien; Marchand-Brynaert, Jacqueline

    2011-12-01

    A novel route for chalcogenide glass surface modification is disclosed. The formation of an organic monolayer from disulfide derivatives is studied on two different glasses of formula GexAsySez by water contact angle measurement, X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy in attenuated total reflection mode (FTIR-ATR). The potential anchoring group is the disulfide functionality. Since thioctic acid derivatives absorb around 335 nm, an irradiation step is included, in order to favor S-S disruption. Three types of disulfide compounds are grafted onto small glass breaks for contact angle and XPS analyses. The results show effective changes of surface state. According to contact angle measurement, the deposited organic layer functionalized by a small polyethylene glycol chain leads to a more hydrophilic surface, long alkyl chain or a perfluorinated carbon chain leads to a more hydrophobic surface. XPS shows the presence at the surface of an organic layer with sulfur and ethylene oxide chains, or augmentation of organic carbons or fluorine and Csbnd F bonds. The photo-assisted grafting of the disulfides onto an ATR prism made of chalcogenide glass shows that this surface modification process does not affect infrared transparency, despite UV treatment, and accurate structural analysis can be performed.

  10. 21 CFR 184.1631 - Potassium hydroxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Potassium hydroxide. 184.1631 Section 184.1631... Listing of Specific Substances Affirmed as GRAS § 184.1631 Potassium hydroxide. (a) Potassium hydroxide..., including pellets, flakes, sticks, lumps, and powders. Potassium hydroxide is obtained commercially from...

  11. 21 CFR 184.1631 - Potassium hydroxide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Potassium hydroxide. 184.1631 Section 184.1631... Listing of Specific Substances Affirmed as GRAS § 184.1631 Potassium hydroxide. (a) Potassium hydroxide..., including pellets, flakes, sticks, lumps, and powders. Potassium hydroxide is obtained commercially from...

  12. 21 CFR 184.1631 - Potassium hydroxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Potassium hydroxide. 184.1631 Section 184.1631... Listing of Specific Substances Affirmed as GRAS § 184.1631 Potassium hydroxide. (a) Potassium hydroxide..., including pellets, flakes, sticks, lumps, and powders. Potassium hydroxide is obtained commercially from...

  13. 21 CFR 184.1631 - Potassium hydroxide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Potassium hydroxide. 184.1631 Section 184.1631 Food... Specific Substances Affirmed as GRAS § 184.1631 Potassium hydroxide. (a) Potassium hydroxide (KOH, CAS Reg... pellets, flakes, sticks, lumps, and powders. Potassium hydroxide is obtained commercially from...

  14. Selected-control synthesis of dysprosium hydroxide and oxide nanorods by adjusting hydrothermal temperature

    SciTech Connect

    Song Xuchun Zheng Yifan; Wang Yun

    2008-05-06

    Dysprosium hydroxide and oxide nanorods were prepared directly from commercial bulk Dy{sub 2}O{sub 3} crystals by facile hydrothermal process at 130 and 210 deg. C, respectively. The as-synthesized dysprosium hydroxide and oxide nanorods were investigated by various techniques of XRD, TEM, SEM, and EDS. In the process, the temperature was found to play important roles in determining produce dysprosium hydroxide and oxide nanorods.

  15. Unprecedented Route to Ordered Polyaniline: Direct Synthesis of Highly Crystalline Fibrillar Films with Strong π-π Stacking Alignment.

    PubMed

    Gospodinova, Natalia; Ivanov, Dimitri A; Anokhin, Denis V; Mihai, Iulia; Vidal, Loïc; Brun, Sulyvan; Romanova, Julia; Tadjer, Alia

    2009-01-01

    Films of polyaniline (PANI) featuring about 80% crystallinity and characterised with strong π-π stacking alignment parallel to the film surface have been obtained directly after the original synthesis upon simple drying of the aqueous PANI suspension. A strong anisotropy in the growth of the nano-sized crystals produced during the synthesis results in the formation of micrometer-length fibrils perpendicular to the film surface in the course of water evaporation. The regular intercalation of water molecules between the PANI chains seems to be crucial for their ordering throughout the synthesis and film formation.

  16. Direct regioselective oxidative cross-coupling of indoles with methyl ketones: a novel route to C3-dicarbonylation of indoles.

    PubMed

    Gao, Qinghe; Zhang, Jingjing; Wu, Xia; Liu, Shan; Wu, Anxin

    2015-01-01

    The first C3-dicarbonylation of indoles was realized through direct oxidative cross-coupling of indoles with methyl ketones in the presence of molecular iodine and pyrrolidine. This reaction constructed a highly efficient indolyl diketones scaffold, which might be regarded as a useful biological and pharmacological tool in the exploration of therapeutic A2BAR modulators. The use of inexpensive molecular iodine and pyrrolidine and a broad substrate scope make this protocol very practical. Preliminary mechanistic studies indicate that two paths are involved in this process.

  17. Hendra virus survival does not explain spillover patterns and implicates relatively direct transmission routes from flying foxes to horses.

    PubMed

    Martin, Gerardo; Plowright, Raina; Chen, Carla; Kault, David; Selleck, Paul; Skerratt, Lee F

    2015-06-01

    Hendra virus (HeV) is lethal to humans and horses, and little is known about its epidemiology. Biosecurity restrictions impede advances, particularly on understanding pathways of transmission. Quantifying the environmental survival of HeV can be used for making decisions and to infer transmission pathways. We estimated HeV survival with a Weibull distribution and calculated parameters from data generated in laboratory experiments. HeV survival rates based on air temperatures 24 h after excretion ranged from 2 to 10 % in summer and from 12 to 33 % in winter. Simulated survival across the distribution of the black flying fox (Pteropus alecto), a key reservoir host, did not predict spillover events. Based on our analyses we concluded that the most likely pathways of transmission did not require long periods of virus survival and were likely to involve relatively direct contact with flying fox excreta shortly after excretion.

  18. Hendra virus survival does not explain spillover patterns and implicates relatively direct transmission routes from flying foxes to horses.

    PubMed

    Martin, Gerardo; Plowright, Raina; Chen, Carla; Kault, David; Selleck, Paul; Skerratt, Lee F

    2015-06-01

    Hendra virus (HeV) is lethal to humans and horses, and little is known about its epidemiology. Biosecurity restrictions impede advances, particularly on understanding pathways of transmission. Quantifying the environmental survival of HeV can be used for making decisions and to infer transmission pathways. We estimated HeV survival with a Weibull distribution and calculated parameters from data generated in laboratory experiments. HeV survival rates based on air temperatures 24 h after excretion ranged from 2 to 10 % in summer and from 12 to 33 % in winter. Simulated survival across the distribution of the black flying fox (Pteropus alecto), a key reservoir host, did not predict spillover events. Based on our analyses we concluded that the most likely pathways of transmission did not require long periods of virus survival and were likely to involve relatively direct contact with flying fox excreta shortly after excretion. PMID:25667321

  19. The use of stream flow routing for direct channel precipitation with isotopically-based hydrograph separations: the role of new water in stormflow generation

    NASA Astrophysics Data System (ADS)

    Renshaw, Carl E.; Feng, Xiahong; Sinclair, Kelsey J.; Dums, Raymond H.

    2003-03-01

    Understanding the pathways by which event water contributes to stream stormflow provides insight into stormflow generation mechanisms. We analyze the impact of storm size on the relative contribution of event water to stormflow by using natural variations in the oxygen isotopic composition of precipitation and stream water to separate multiple stormflow hydrographs from a single fourth-order, 1212 ha catchment. We extend previous isotope-based hydrograph separations by independently accounting for the contribution of event water via direct channel precipitation to the stream hydrograph. The direct channel precipitation contribution is determined using a numerical model of stream flow routing though the catchment, taking precipitation and digital elevation data as input variables. For the range of storm sizes sampled, having recurrence intervals ranging from less than a week to ˜4 months, essentially all the event water in stream stormflow can be attributed to direct channel precipitation. Event water not directly falling on the stream channel indirectly contributes to stormflow by increasing the subsurface discharge of pre-event water to the stream. Neither the hydrograph separation data, field observations during the precipitation events, nor experimental observations of flow in a large-scale natural soil column extracted from the watershed are consistent with macropore flow or groundwater ridging as the primary mechanism responsible for increasing subsurface discharge. Results from a series of artificial rain experiments using the unsaturated natural soil column are consistent with a preferential kinematic flow model and indicate that the discharge of pre-event water to the stream during a storm event may be controlled by kinematic flow processes within the watershed soils.

  20. "Recalculating Route".

    PubMed

    Baum, Neil

    2015-01-01

    Can you imagine going to a doctor who uses a paper chart, sends you a bill on a ledger card, and handwrites a prescription? You wouldn't have a great deal of confidence that the clinical skills of the doctor were up to date. This would be an example of a doctor who did not "recalculate his or her route." This article provides 10 examples of adjustments that have been made in medicine where the route has been recalculated. PMID:26399043

  1. 21 CFR 582.1139 - Ammonium hydroxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... Additives § 582.1139 Ammonium hydroxide. (a) Product. Ammonium hydroxide. (b) Conditions of use. This substance is generally recognized as safe when used in accordance with good manufacturing or...

  2. 21 CFR 582.1139 - Ammonium hydroxide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Additives § 582.1139 Ammonium hydroxide. (a) Product. Ammonium hydroxide. (b) Conditions of use. This substance is generally recognized as safe when used in accordance with good manufacturing or...

  3. 21 CFR 184.1205 - Calcium hydroxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... Specific Substances Affirmed as GRAS § 184.1205 Calcium hydroxide. (a) Calcium hydroxide (Ca(OH)2, CAS Reg... lime. (b) The ingredient meets the specifications of the Food Chemicals Codex, 3d Ed. (1981), p....

  4. 21 CFR 184.1205 - Calcium hydroxide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Specific Substances Affirmed as GRAS § 184.1205 Calcium hydroxide. (a) Calcium hydroxide (Ca(OH)2, CAS Reg... lime. (b) The ingredient meets the specifications of the Food Chemicals Codex, 3d Ed. (1981), p....

  5. 21 CFR 184.1205 - Calcium hydroxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... GRAS § 184.1205 Calcium hydroxide. (a) Calcium hydroxide (Ca(OH)2, CAS Reg. No. 1305-62-0) is also... meets the specifications of the Food Chemicals Codex, 3d Ed. (1981), p. 52, which is incorporated...

  6. 21 CFR 184.1205 - Calcium hydroxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... Specific Substances Affirmed as GRAS § 184.1205 Calcium hydroxide. (a) Calcium hydroxide (Ca(OH)2, CAS Reg... lime. (b) The ingredient meets the specifications of the Food Chemicals Codex, 3d Ed. (1981), p....

  7. 21 CFR 184.1205 - Calcium hydroxide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... Specific Substances Affirmed as GRAS § 184.1205 Calcium hydroxide. (a) Calcium hydroxide (Ca(OH)2, CAS Reg... lime. (b) The ingredient meets the specifications of the Food Chemicals Codex, 3d Ed. (1981), p....

  8. 21 CFR 582.1631 - Potassium hydroxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Potassium hydroxide. 582.1631 Section 582.1631 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1631 Potassium hydroxide. (a) Product. Potassium hydroxide. (b) Conditions of use....

  9. 21 CFR 582.1631 - Potassium hydroxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Potassium hydroxide. 582.1631 Section 582.1631 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1631 Potassium hydroxide. (a) Product. Potassium hydroxide. (b) Conditions of use....

  10. 21 CFR 582.1631 - Potassium hydroxide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Potassium hydroxide. 582.1631 Section 582.1631 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1631 Potassium hydroxide. (a) Product. Potassium hydroxide. (b) Conditions of use....

  11. 21 CFR 582.1631 - Potassium hydroxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Potassium hydroxide. 582.1631 Section 582.1631 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1631 Potassium hydroxide. (a) Product. Potassium hydroxide. (b) Conditions of use....

  12. 21 CFR 582.1428 - Magnesium hydroxide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Magnesium hydroxide. 582.1428 Section 582.1428 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1428 Magnesium hydroxide. (a) Product. Magnesium hydroxide. (b) Conditions of use....

  13. 21 CFR 582.1428 - Magnesium hydroxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Magnesium hydroxide. 582.1428 Section 582.1428 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1428 Magnesium hydroxide. (a) Product. Magnesium hydroxide. (b) Conditions of use....

  14. 21 CFR 582.1428 - Magnesium hydroxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Magnesium hydroxide. 582.1428 Section 582.1428 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1428 Magnesium hydroxide. (a) Product. Magnesium hydroxide. (b) Conditions of use....

  15. 21 CFR 582.1428 - Magnesium hydroxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Magnesium hydroxide. 582.1428 Section 582.1428 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1428 Magnesium hydroxide. (a) Product. Magnesium hydroxide. (b) Conditions of use....

  16. 21 CFR 582.1205 - Calcium hydroxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Calcium hydroxide. 582.1205 Section 582.1205 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1205 Calcium hydroxide. (a) Product. Calcium hydroxide. (b) Conditions of use....

  17. 21 CFR 582.1205 - Calcium hydroxide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium hydroxide. 582.1205 Section 582.1205 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1205 Calcium hydroxide. (a) Product. Calcium hydroxide. (b) Conditions of use....

  18. 21 CFR 582.1205 - Calcium hydroxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Calcium hydroxide. 582.1205 Section 582.1205 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1205 Calcium hydroxide. (a) Product. Calcium hydroxide. (b) Conditions of use....

  19. 21 CFR 582.1205 - Calcium hydroxide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Calcium hydroxide. 582.1205 Section 582.1205 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1205 Calcium hydroxide. (a) Product. Calcium hydroxide. (b) Conditions of use....

  20. 21 CFR 582.1205 - Calcium hydroxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Calcium hydroxide. 582.1205 Section 582.1205 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1205 Calcium hydroxide. (a) Product. Calcium hydroxide. (b) Conditions of use....

  1. 21 CFR 582.1631 - Potassium hydroxide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Potassium hydroxide. 582.1631 Section 582.1631 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1631 Potassium hydroxide. (a) Product. Potassium hydroxide. (b) Conditions of use....

  2. 21 CFR 582.1763 - Sodium hydroxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Sodium hydroxide. 582.1763 Section 582.1763 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1763 Sodium hydroxide. (a) Product. Sodium hydroxide. (b) Conditions of use. This...

  3. 21 CFR 582.1763 - Sodium hydroxide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Sodium hydroxide. 582.1763 Section 582.1763 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1763 Sodium hydroxide. (a) Product. Sodium hydroxide. (b) Conditions of use. This...

  4. 21 CFR 582.1428 - Magnesium hydroxide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Magnesium hydroxide. 582.1428 Section 582.1428 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1428 Magnesium hydroxide. (a) Product. Magnesium hydroxide. (b) Conditions of use....

  5. 21 CFR 582.1763 - Sodium hydroxide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Sodium hydroxide. 582.1763 Section 582.1763 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1763 Sodium hydroxide. (a) Product. Sodium hydroxide. (b) Conditions of use. This...

  6. 21 CFR 582.1763 - Sodium hydroxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Sodium hydroxide. 582.1763 Section 582.1763 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1763 Sodium hydroxide. (a) Product. Sodium hydroxide. (b) Conditions of use. This...

  7. 21 CFR 582.1763 - Sodium hydroxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Sodium hydroxide. 582.1763 Section 582.1763 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1763 Sodium hydroxide. (a) Product. Sodium hydroxide. (b) Conditions of use. This...

  8. 21 CFR 184.1763 - Sodium hydroxide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Specific Substances Affirmed as GRAS § 184.1763 Sodium hydroxide. (a) Sodium hydroxide (NaOH, CAS Reg. No... empirical formula is NaOH. Sodium hydroxide is prepared commercially by the electrolysis of sodium chloride... following current good manufacturing practice conditions of use: (1) The ingredient is used as a pH...

  9. 21 CFR 184.1763 - Sodium hydroxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... Specific Substances Affirmed as GRAS § 184.1763 Sodium hydroxide. (a) Sodium hydroxide (NaOH, CAS Reg. No... empirical formula is NaOH. Sodium hydroxide is prepared commercially by the electrolysis of sodium chloride... following current good manufacturing practice conditions of use: (1) The ingredient is used as a pH...

  10. 21 CFR 184.1763 - Sodium hydroxide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... Specific Substances Affirmed as GRAS § 184.1763 Sodium hydroxide. (a) Sodium hydroxide (NaOH, CAS Reg. No... empirical formula is NaOH. Sodium hydroxide is prepared commercially by the electrolysis of sodium chloride... following current good manufacturing practice conditions of use: (1) The ingredient is used as a pH...

  11. 21 CFR 184.1763 - Sodium hydroxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... Specific Substances Affirmed as GRAS § 184.1763 Sodium hydroxide. (a) Sodium hydroxide (NaOH, CAS Reg. No... empirical formula is NaOH. Sodium hydroxide is prepared commercially by the electrolysis of sodium chloride... following current good manufacturing practice conditions of use: (1) The ingredient is used as a pH...

  12. 21 CFR 582.1139 - Ammonium hydroxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Ammonium hydroxide. 582.1139 Section 582.1139 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1139 Ammonium hydroxide. (a) Product. Ammonium hydroxide. (b) Conditions of use....

  13. Lipidomic and transcriptomic analyses of Chlamydomonas reinhardtii under heat stress unveil a direct route for the conversion of membrane lipids into storage lipids.

    PubMed

    Légeret, B; Schulz-Raffelt, M; Nguyen, H M; Auroy, P; Beisson, F; Peltier, G; Blanc, G; Li-Beisson, Y

    2016-04-01

    Studying how photosynthetic cells modify membrane lipids in response to heat stress is important to understand how plants and microalgae adapt to daily fluctuations in temperature and to investigate new lipid pathways. Here, we investigate changes occurring in lipid molecular species and lipid metabolism genes during early response to heat stress in the model photosynthetic microorganism Chlamydomonas reinhardtii. Lipid molecular species analyses revealed that, after 60 min at 42 °C, a strong decrease in specific polyunsaturated membrane lipids was observed together with an increase in polyunsaturated triacylglycerols (TAGs) and diacylglycerols (DAGs). The fact that decrease in the major chloroplastic monogalactosyldiacylglycerol sn1-18:3/sn2-16:4 was mirrored by an accumulation of DAG sn1-18:3/sn2-16:4 and TAG sn1-18:3/sn2-16:4/sn3-18:3 indicated that newly accumulated TAGs were formed via direct conversion of monogalactosyldiacylglycerols to DAGs then TAGs. Lipidomic analyses showed that the third fatty acid of a TAG likely originated from a phosphatidylethanolamine or a diacylglyceryl-O-4'-(N,N,N,-trimethyl)-homoserine betaine lipid species. Candidate genes for this TAG synthesis pathway were provided through comparative transcriptomic analysis and included a phospholipase A2 homolog and the DAG acyltransferase DGTT1. This study gives insights into the molecular events underlying changes in membrane lipids during heat stress and reveals an alternative route for TAG synthesis. PMID:26477535

  14. Analysis of barium hydroxide and calcium hydroxide slurry carbonation reactors

    SciTech Connect

    Patch, K.D.; Hart, R.P.; Schumacher, W.A.

    1980-05-01

    The removal of CO/sub 2/ from air was investigated by using a continuous-agitated-slurry carbonation reactor containing either barium hydroxide (Ba(OH)/sub 2/) or calcium hydroxide (Ca(OH)/sub 2/). Such a process would be applied to scrub /sup 14/CO/sub 2/ from stack gases at nuclear-fuel reprocessing plants. Decontamination factors were characterized for reactor conditions which could alter hydrodynamic behavior. An attempt was made to characterize reactor performance with models assuming both plug flow and various degrees of backmixing in the gas phase. The Ba(OH)/sub 2/ slurry enabled increased conversion, but apparently the process was controlled under some conditions by phenomena differing from those observed for carbonation by Ca(OH)/sub 2/. Overall reaction mechanisms are postulated.

  15. Synthesis of the high temperature superconductor YBa 2Cu 3O 7-δ by the hydroxide co-precipitation method

    NASA Astrophysics Data System (ADS)

    Schildermans, I.; Van Bael, M.; Knaepen, E.; Yperman, J.; Mullens, J.; Van Poucke, L. C.

    1997-02-01

    A new synthetic route is developed to prepare a hydroxide precursor for the superconductor YBa 2Cu 3O 7-δ. In an inert atmosphere and at low temperature the yttrium, barium and copper hydroxides are co-precipitated by adding the metal perchlorates and sodium hydroxide together. The analysis of the precursor proved the absence of ClO 4- and Na + ions. The thermal treatment (12 h calcinating at 950°C, 36 h sintering at 950°C and 6 h annealing at 400°C) gives a superconductor YBa 2Cu 3O 7-δ with a transition temperature of 90.2 K.

  16. Comparative Efficacy and Safety of Multiple Routes of Direct CNS Administration of Adeno-Associated Virus Gene Transfer Vector Serotype rh.10 Expressing the Human Arylsulfatase A cDNA to Nonhuman Primates

    PubMed Central

    Rosenberg, Jonathan B.; Sondhi, Dolan; Rubin, David G.; Monette, Sébastien; Chen, Alvin; Cram, Sara; De, Bishnu P.; Kaminsky, Stephen M.; Sevin, Caroline; Aubourg, Patrick

    2014-01-01

    Abstract Metachromatic leukodystrophy (MLD), a fatal disorder caused by deficiency of the lysosomal enzyme arylsulfatase A (ARSA), is associated with an accumulation of sulfatides, causing widespread demyelination in both central and peripheral nervous systems. On the basis of prior studies demonstrating that adeno-associated virus AAVrh.10 can mediate widespread distribution in the CNS of a secreted lysosomal transgene, and as a prelude to human trials, we comparatively assessed the optimal CNS delivery route of an AAVrh.10 vector encoding human ARSA in a large animal model for broadest distribution of ARSA enzyme. Five routes were tested (each total dose, 1.5×1012 genome copies of AAVrh.10hARSA-FLAG): (1) delivery to white matter centrum ovale; (2) deep gray matter delivery (putamen, thalamus, and caudate) plus overlying white matter; (3) convection-enhanced delivery to same deep gray matter locations; (4) lateral cerebral ventricle; and (5) intraarterial delivery with hyperosmotic mannitol to the middle cerebral artery. After 13 weeks, the distribution of ARSA activity subsequent to each of the three direct intraparenchymal administration routes was significantly higher than in phosphate-buffered saline-administered controls, but administration by the intraventricular and intraarterial routes failed to demonstrate measurable levels above controls. Immunohistochemical staining in the cortex, white matter, deep gray matter of the striatum, thalamus, choroid plexus, and spinal cord dorsal root ganglions confirmed these results. Of the five routes studied, administration to the white matter generated the broadest distribution of ARSA, with 80% of the brain displaying more than a therapeutic (10%) increase in ARSA activity above PBS controls. No significant toxicity was observed with any delivery route as measured by safety parameters, although some inflammatory changes were seen by histopathology. We conclude that AAVrh.10-mediated delivery of ARSA via CNS

  17. INFLUENCE OF IODOFORM ON ANTIMICROBIAL POTENTIAL OF CALCIUM HYDROXIDE

    PubMed Central

    Estrela, Carlos; Estrela, Cyntia Rodrigues de Araújo; Hollanda, Augusto César Braz; Decurcio, Daniel de Almeida; Pécora, Jesus Djalma

    2006-01-01

    The purpose of this research was to verify the influence of Iodoform on antimicrobial potential of calcium hydroxide. S. aureus, E. faecalis, P. aeruginosa, B. subtilis, C. albicans were the biological indicators. The substances tested were: calcium hydroxide + saline; calcium hydroxide + Iodoform + saline; Iodoform + saline. For the agar diffusion test, 18 Petri plates with 20 ml of BHI agar were inoculated with the microbial suspensions. Fifty-four cavities were made and filled with the substances tested. The diameters of microbial inhibition were then measured. In direct exposure test, 162 #50 sterile absorbent paper points were immersed in the experimental suspensions for 5 min, and covered with the pastes. At intervals of 24, 48 and 72 hours, the paper points were immersed in 10 ml of Letheen Broth, followed by incubation at 37°°C for 48h. Microbial growth was evaluated by turbidity of the culture medium. A 0.1 ml inoculum obtained from the Letheen Broth was transferred to 7 ml of BHI, and incubated at 37°°C for 48h. Bacterial growth was again evaluated by turbidity of the culture medium. The calcium hydroxide associated with the saline or the iodoform plus saline showed antimicrobial effectiveness in both experimental methods. The iodoform paste presented antimicrobial ineffectiveness for the agar diffusion test on all biological microorganisms and for the direct exposure test on B. subtilis and on the mixture. PMID:19089027

  18. Collective network routing

    SciTech Connect

    Hoenicke, Dirk

    2014-12-02

    Disclosed are a unified method and apparatus to classify, route, and process injected data packets into a network so as to belong to a plurality of logical networks, each implementing a specific flow of data on top of a common physical network. The method allows to locally identify collectives of packets for local processing, such as the computation of the sum, difference, maximum, minimum, or other logical operations among the identified packet collective. Packets are injected together with a class-attribute and an opcode attribute. Network routers, employing the described method, use the packet attributes to look-up the class-specific route information from a local route table, which contains the local incoming and outgoing directions as part of the specifically implemented global data flow of the particular virtual network.

  19. 21 CFR 184.1428 - Magnesium hydroxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... GRAS § 184.1428 Magnesium hydroxide. (a) Magnesium hydroxide (Mg(OH)2, CAS Reg. No. 1309-42-8) occurs... magnesium oxide. (b) The ingredient meets the specifications of the Food Chemicals Codex, 3d Ed. (1981), p...: (1) The ingredient is used as a nutrient supplement as defined in § 170.3(o)(20) of this chapter; a...

  20. 21 CFR 184.1763 - Sodium hydroxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... GRAS § 184.1763 Sodium hydroxide. (a) Sodium hydroxide (NaOH, CAS Reg. No. 1310-73-2) is also known as sodium hydrate, soda lye, caustic soda, white caustic, and lye. The empirical formula is NaOH. Sodium... manufacturing practice conditions of use: (1) The ingredient is used as a pH control agent as defined in §...

  1. Pretreatment of rapeseed straw by sodium hydroxide.

    PubMed

    Kang, Kyeong Eop; Jeong, Gwi-Taek; Park, Don-Hee

    2012-06-01

    Pretreatment method for rapeseed straw by sodium hydroxide was investigated for production of bioethanol and biobutanol. Various pretreatment parameters, including temperature, time, and sodium hydroxide concentration were optimized using a statistical method which is a central composite design of response surface methodology. In the case of sodium hydroxide pretreatment, optimal pretreatment conditions were found to be 7.9% sodium hydroxide concentration, 5.5 h of reaction time, and 68.4 °C of reaction temperature. The maximum glucose yield which can be recovered by enzymatic hydrolysis at the optimum conditions was 95.7% and the experimental result was 94.0 ± 4.8%. This experimental result was in agreement with the model prediction. An increase of surface area and pore size in pretreated rapeseed straw by sodium hydroxide pretreatment was observed by scanning electron microscope.

  2. Formation and Stability of Ni-Al Hydroxide Phases in Soils

    SciTech Connect

    Peltier, E.; Van Der Lelie, D; Sparks, D

    2010-01-01

    The formation of mixed metal-aluminum hydroxide surface precipitates is a potentially significant uptake route for trace metals (including Co, Ni, and Zn) in environmental systems. This paper investigates the effect of mixed Ni-Al hydroxide precipitate formation and aging on Ni solubility and bioavailability in laboratory contaminated soils. Two Delaware agricultural soils were reacted with a 3 mM Ni solution for 12 months at pH's above and below the threshold for mixed Ni-Al hydroxide formation. Ni speciation was determined at 1, 6, and 12 months using X-ray absorption spectroscopy (XAS). Precipitate solubility was examined through desorption experiments using HNO{sub 3} and EDTA as desorbing agents, whereas metal bioavailability was assessed using a Ni-specific bacterial biosensor. For both soils, the formation of Ni-Al hydroxide surface precipitates resulted in a reduction in the fraction of desorbed and bioavailable Ni. However, precipitate dissolution was greater, particularly with EDTA, than in published studies on isolated soil clay fractions, and less affected by aging processes. These results suggest that mixed Ni-Al hydroxide phases forming in real world environments may be both longer-lasting and more susceptible to ligand-promoted dissolution than previously expected.

  3. Zone routing in a torus network

    DOEpatents

    Chen, Dong; Heidelberger, Philip; Kumar, Sameer

    2013-01-29

    A system for routing data in a network comprising a network logic device at a sending node for determining a path between the sending node and a receiving node, wherein the network logic device sets one or more selection bits and one or more hint bits within the data packet, a control register for storing one or more masks, wherein the network logic device uses the one or more selection bits to select a mask from the control register and the network logic device applies the selected mask to the hint bits to restrict routing of the data packet to one or more routing directions for the data packet within the network and selects one of the restricted routing directions from the one or more routing directions and sends the data packet along a link in the selected routing direction toward the receiving node.

  4. Hierarchical cobalt-based hydroxide microspheres for water oxidation.

    PubMed

    Zhang, Ye; Cui, Bai; Derr, Olivia; Yao, Zhibo; Qin, Zhaotong; Deng, Xiangyun; Li, Jianbao; Lin, Hong

    2014-03-21

    3D hierarchical cobalt hydroxide carbonate hydrate (Co(CO3)0.5(OH)·0.11H2O) has been synthesized featuring a hollow urchin-like structure by a one-step hydrothermal method at modest temperature on FTO glass substrates. The functionalities of precursor surfactants were isolated and analyzed. A plausible formation mechanism of the spherical urchin-like microclusters has been furnished through time-dependent investigations. Introduction of other transitional metal doping (Cu, Ni) would give rise to a substantial morphological change associated with a surface area drop. The directly grown cobalt-based hydroxide composite electrodes were found to be capable of catalyzing oxygen evolution reaction (OER) under both neutral pH and alkaline conditions. The favorable 3D dendritic morphology and porous structure provide large surface areas and possible defect sites that are likely responsible for their robust electrochemical activity.

  5. Dynamic Weather Routes Architecture Overview

    NASA Technical Reports Server (NTRS)

    Eslami, Hassan; Eshow, Michelle

    2014-01-01

    Dynamic Weather Routes Architecture Overview, presents the high level software architecture of DWR, based on the CTAS software framework and the Direct-To automation tool. The document also covers external and internal data flows, required dataset, changes to the Direct-To software for DWR, collection of software statistics, and the code structure.

  6. CO2 sequestration using waste concrete and anorthosite tailings by direct mineral carbonation in gas-solid-liquid and gas-solid routes.

    PubMed

    Ben Ghacham, Alia; Cecchi, Emmanuelle; Pasquier, Louis-César; Blais, Jean-François; Mercier, Guy

    2015-11-01

    Mineral carbonation (MC) represents a promising alternative for sequestering CO2. In this work, the CO2 sequestration capacity of the available calcium-bearing materials waste concrete and anorthosite tailings is assessed in gas-solid-liquid and gas-solid routes using 18.2% flue CO2 gas. The objective is to screen for a better potential residue and phase route and as the ultimate purpose to develop a cost-effective process. The results indicate the possibility of removing 66% from inlet CO2 using waste concrete for the aqueous route. However, the results that were obtained with the carbonation of anorthosite were less significant, with 34% as the maximal percentage of CO2 removal. The difference in terms of reactivity could be explained by the accessibility to calcium. In fact, anorthosite presents a framework structure wherein the calcium is trapped, which could slow the calcium dissolution into the aqueous phase compared to the concrete sample, where calcium can more easily leach. In the other part of the study concerning gas-solid carbonation, the results of CO2 removal did not exceed 15%, which is not economically interesting for scaling up the process. The results obtained with waste concrete samples in aqueous phase are interesting. In fact, 34.6% of the introduced CO2 is converted into carbonate after 15 min of contact with the gas without chemical additives and at a relatively low gas pressure. Research on the optimization of the aqueous process using waste concrete should be performed to enhance the reaction rate and to develop a cost-effective process. PMID:26292776

  7. CO2 sequestration using waste concrete and anorthosite tailings by direct mineral carbonation in gas-solid-liquid and gas-solid routes.

    PubMed

    Ben Ghacham, Alia; Cecchi, Emmanuelle; Pasquier, Louis-César; Blais, Jean-François; Mercier, Guy

    2015-11-01

    Mineral carbonation (MC) represents a promising alternative for sequestering CO2. In this work, the CO2 sequestration capacity of the available calcium-bearing materials waste concrete and anorthosite tailings is assessed in gas-solid-liquid and gas-solid routes using 18.2% flue CO2 gas. The objective is to screen for a better potential residue and phase route and as the ultimate purpose to develop a cost-effective process. The results indicate the possibility of removing 66% from inlet CO2 using waste concrete for the aqueous route. However, the results that were obtained with the carbonation of anorthosite were less significant, with 34% as the maximal percentage of CO2 removal. The difference in terms of reactivity could be explained by the accessibility to calcium. In fact, anorthosite presents a framework structure wherein the calcium is trapped, which could slow the calcium dissolution into the aqueous phase compared to the concrete sample, where calcium can more easily leach. In the other part of the study concerning gas-solid carbonation, the results of CO2 removal did not exceed 15%, which is not economically interesting for scaling up the process. The results obtained with waste concrete samples in aqueous phase are interesting. In fact, 34.6% of the introduced CO2 is converted into carbonate after 15 min of contact with the gas without chemical additives and at a relatively low gas pressure. Research on the optimization of the aqueous process using waste concrete should be performed to enhance the reaction rate and to develop a cost-effective process.

  8. A new route for the synthesis of titanium silicalite-1

    SciTech Connect

    Vasile, Aurelia; Busuioc-Tomoiaga, Alina Maria

    2012-01-15

    Graphical abstract: Well-prepared TS-1 was synthesized by an innovative procedure using inexpensive reagents such as fumed silica and TPABr as structure-directing agent. This is the first time when highly crystalline TS-1 is obtained in basic medium, using sodium hydroxide as HO{sup -} ion source required for the crystallization process. Hydrolysis of titanium source has been prevented by titanium complexation with acetylacetone before structuring gel. Highlights: Black-Right-Pointing-Pointer TS-1 was obtained using cheap reagents as fumed silica and tetrapropylammonium bromide. Black-Right-Pointing-Pointer First time NaOH was used as source of OH{sup -} ions required for crystallization process. Black-Right-Pointing-Pointer The hydrolysis Ti alkoxides was controlled by Ti complexation with 2,4-pentanedione. -- Abstract: A new and efficient route using inexpensive reagents such as fumed silica and tetrapropylammonium bromide is proposed for the synthesis of titanium silicalite-1. High crystalline titanium silicalite-1 was obtained in alkaline medium, using sodium hydroxide as HO{sup -} ion source required for the crystallization process. Hydrolysis of titanium source with formation of insoluble oxide species was prevented by titanium complexation with before structuring gel. The final solids were fully characterized by powder X-ray diffraction, scanning electron microscopy, Fourier transform infrared, ultraviolet-visible diffuse reflectance, Raman and atomic absorption spectroscopies, as well as nitrogen sorption analysis. It was found that a molar ratio Ti:Si of about 0.04 in the initial reaction mixture is the upper limit to which well formed titanium silicalite-1 with channels free of crystalline or amorphous material can be obtained. Above this value, solids with MFI type structure containing both Ti isomorphously substituted in the network and extralattice anatase nanoparticles inside of channels is formed.

  9. Copper, silver, gold and zinc, cadmium, mercury oxides and hydroxides

    SciTech Connect

    Dirkse, T.P.

    1986-01-01

    This book provides a compilation of solubility data published up to 1984, including evaluations of the data. Data are presented on the following: copper (I) oxide; copper (II) oxide and hydroxide; silver (I) oxide; silver (II) oxide; gold (III) hydroxide; zinc oxide and hydroxide; cadmium oxide and hydroxide; and mercury (II) oxide.

  10. 21 CFR 184.1428 - Magnesium hydroxide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Specific Substances Affirmed as GRAS § 184.1428 Magnesium hydroxide. (a) Magnesium hydroxide (Mg(OH)2, CAS... Chemicals Codex, 3d Ed. (1981), p. 178, which is incorporated by reference. Copies are available from the... § 170.3(o)(20) of this chapter; a pH control agent as defined in § 170.3(o)(23) of this chapter; and...

  11. Part I. Layered Double Hydroxides

    NASA Astrophysics Data System (ADS)

    Dimotakis, Emmanuel Dimitrios

    A new general method for the preparation of well -ordered layered double hydroxides (LDHs), (Mg_ {rm 1-x}Al_{ rm x} (OH)_2) (X^{rm n-}) _{rm n/x}{cdot}yH _2O, interlayered by organic anions has been developed. It is based on the reaction of meixnerite, (Mg_3Al(OH)_8) (OH) cdot2H_2O, with the free acid form of the desired anion--using glycerol as a swelling agent--to yield single crystalline products that are not readily available by conventional synthetic methods. The (Mg_3Al(OH) _8) -adipate and -p-toluenesulfonate derivatives undergo facile ion exchange reactions with Keggin-type (XM_{12}O_ {40}) ^{rm n -} or lacunary (XM_{11 }O_{39}) ^{rm m-} polyoxometalates (POMs) to form well-ordered, microporous pillared derivatives with the highest N_2 BET surface areas reported to date, namely 107 and 155 m^2 /g, respectively. Meixnerite, (Mg_3Al(OH) _8) (OH) cdot2H _2O, has unexpectedly been found to undergo similar ion exchange reactions, in a topotactic way, with retention of the structure of the intercalated POMs. The meixnerite was conveniently prepared for the first time from calcination of (Mg_3Al(OH) _8) (CO_3) _{0.5}{cdot}2H _2O and aqueous hydrolysis of the resulting NaCl-type solid solution. Metal carbonyl clusters have also been examined for ion-exchange (i.e., { (Pt _3(CO)_6) _{rm n}}^ {2-}) in these LDH-precursors. This chemistry is compared with the surface chemistry of (Mg_3 Al(OH)_8) (X^ {rm n-}) _{ rm 1/n}{cdot}2H _2O (X = CO_3^{2 -} or OH^{-}). It has been shown that the surface hydrolysis reaction: CO _3^{2-} + H _2O longrightarrow HCO_3^{-} + OH ^-, causes reductive condensation reactions of neutral carbonyl clusters with the LDH. The reactions were as efficient as with Na metal in solution. In part II of this work, Li-fluorohectorite, has been pillared with titanium polyoxocations derived from the acidic hydrolysis of TiCl_4 or Ti(i-OC_3H_7) _4. Raman spectroscopy of the product indicates that the pillars have a structure analogous to TiO_2(B) phase

  12. Visualizing Internet routing changes.

    PubMed

    Lad, Mohit; Massey, Dan; Zhang, Lixia

    2006-01-01

    Today's Internet provides a global data delivery service to millions of end users and routing protocols play a critical role in this service. It is important to be able to identify and diagnose any problems occurring in Internet routing. However, the Internet's sheer size makes this task difficult. One cannot easily extract out the most important or relevant routing information from the large amounts of data collected from multiple routers. To tackle this problem, we have developed Link-Rank, a tool to visualize Internet routing changes at the global scale. Link-Rank weighs links in a topological graph by the number of routes carried over each link and visually captures changes in link weights in the form of a topological graph with adjustable size. Using Link-Rank, network operators can easily observe important routing changes from massive amounts of routing data, discover otherwise unnoticed routing problems, understand the impact of topological events, and infer root causes of observed routing changes.

  13. Iodine Sequestration Using Delafossites and Layered Hydroxides

    SciTech Connect

    J.D. Pless; J.B. Chwirka; J.L. Krumhansl

    2006-03-28

    The objective of this document is to report on early success for sequestering {sup 129}I. Sorption coefficients (K{sub d}) for I{sup -} and IO{sub 3}{sup -} onto delafossites, spinels and layered metal hydroxides were measured in order to compare their applicability for sequestering {sup 129}I. The studies were performed using a dilute fluid composition representative of groundwater indigenous to the Yucca mountain area. Delafossites generally exhibited relatively poor sorption coefficients (< 10{sup 1.7} mL/g). In contrast, the composition of the layered hydroxides significantly affects their ability to sorb I. Cu/Al and Cu/Cr layered hydroxide samples exhibit K{sub d}'s greater than 10{sup 3} mL/g for both I{sup -} and IO{sub 3}{sup -}.

  14. Method of manufacturing positive nickel hydroxide electrodes

    DOEpatents

    Gutjahr, M.A.; Schmid, R.; Beccu, K.D.

    1975-12-16

    A method of manufacturing a positive nickel hydroxide electrode is discussed. A highly porous core structure of organic material having a fibrous or reticular texture is uniformly coated with nickel powder and then subjected to a thermal treatment which provides sintering of the powder coating and removal of the organic core material. A consolidated, porous nickel support structure is thus produced which has substantially the same texture and porosity as the initial core structure. To provide the positive electrode including the active mass, nickel hydroxide is deposited in the pores of the nickel support structure.

  15. Direct measurements of the tile drain and groundwater flow route contributions to surface water contamination: From field-scale concentration patterns in groundwater to catchment-scale surface water quality.

    PubMed

    Rozemeijer, J C; van der Velde, Y; van Geer, F C; Bierkens, M F P; Broers, H P

    2010-12-01

    Enhanced knowledge of water and solute pathways in catchments would improve the understanding of dynamics in water quality and would support the selection of appropriate water pollution mitigation options. For this study, we physically separated tile drain effluent and groundwater discharge from an agricultural field before it entered a 43.5-m ditch transect. Through continuous discharge measurements and weekly water quality sampling, we directly quantified the flow route contributions to surface water discharge and solute loading. Our multi-scale experimental approach allowed us to relate these measurements to field-scale NO(3) concentration patterns in shallow groundwater and to continuous NO(3) records at the catchment outlet. Our results show that the tile drains contributed 90-92% of the annual NO(3) and heavy metal loads. Considering their crucial role in water and solute transport, enhanced monitoring and modeling of tile drainage are important for adequate water quality management.

  16. A direct route for the investigation of crystalline field effects on the spectral properties of Eu{sup 3+} ions in designed nanostructures

    SciTech Connect

    Yu, Hua Guo, Hui; Zhang, Xiaoyu; Lao, Aiqing; Gao, Shaohua; Li, Qingxuan; Zhao, Lijuan

    2015-08-28

    The spectral properties of lanthanide ions doped in a solid-state matrix, especially the Stark splitting and emission shifts, are strongly influenced by the local crystalline field. Here, we use a direct approach to quantitatively investigate the crystalline field effect on these spectral properties of Eu{sup 3+} ions in our designed β-PbF{sub 2}:Eu{sup 3+} and BaF{sub 2}:Eu{sup 3+} nanostructures. The extremely similar structures in which the central Eu{sup 3+} ions have the same site symmetry allow the local crystalline field to be simplified as the same point charge electrostatic field model. In this model, the direction and intensity of the electrostatic field are related to the distortion and expansion degree of the charge cloud of the luminescent center, respectively, and further determine the Stark splitting and emission shift. The theoretical analysis and charge-cloud stimulations were in good agreement with the experimental results. The direction and intensity of the crystalline field were calculated, and showed that the emission spectra shift to red with the increase in intensity. This work provides a comprehensive understanding of the spectral changes induced by a crystalline field, which is of great significance for the design of materials with the desired spectral properties.

  17. Structural transformation of nickel hydroxide films during anodic oxidation

    SciTech Connect

    Crocker, R.W.; Muller, R.H.

    1992-05-01

    The transformation of anodically formed nickel hydroxide/oxy-hydroxide electrodes has been investigated. A mechanism is proposed for the anodic oxidation reaction, in which the reaction interface between the reduced and oxidized phases of the electrode evolves in a nodular topography that leads to inefficient utilization of the active electrode material. In the proposed nodular transformation model for the anodic oxidation reaction, nickel hydroxide is oxidized to nickel oxy-hydroxide in the region near the metal substrate. Since the nickel oxy-hydroxide is considerably more conductive than the surrounding nickel hydroxide, as further oxidation occurs, nodular features grow rapidly to the film/electrolyte interface. Upon emerging at the electrolyte interface, the reaction boundary between the nickel hydroxide and oxy-hydroxide phases spreads laterally across the film/electrolyte interface, creating an overlayer of nickel oxy-hydroxide and trapping uncharged regions of nickel hydroxide within the film. The nickel oxy-hydroxide overlayer surface facilitates the oxygen evolution side reaction. Scanning tunneling microscopy of the electrode in its charged state revealed evidence of 80 {endash} 100 Angstrom nickel oxy-hydroxide nodules in the nickel hydroxide film. In situ spectroscopic ellipsometer measurements of films held at various constant potentials agree quantitatively with optical models appropriate to the nodular growth and subsequent overgrowth of the nickel oxy-hydroxide phase. A two-dimensional, numerical finite difference model was developed to simulate the current distribution along the phase boundary between the charged and uncharged material. The model was used to explore the effects of the physical parameters that govern the electrode behavior. The ratio of the conductivities of the nickel hydroxide and oxy-hydroxide phases was found to be the dominant parameter in the system.

  18. Magnetically retrievable nickel hydroxide functionalised AFe2O4 (A = Mn, Ni) spinel nanocatalyst for alcohol oxidation

    NASA Astrophysics Data System (ADS)

    Bhat, Pooja B.; Bhat, Badekai Ramachandra

    2016-03-01

    Ultrasmall nickel hydroxide functionalised AFe2O4 (A = Mn, Ni) nanocatalyst was synthesized by traditional co-precipitation method and was examined for oxidation of aromatic alcohols to carbonyls using hydrogen peroxide as terminal oxidant. A very high surface area of 104.55 m2 g-1 was achieved for ferromagnetic MnFe2O4 and 100.50 m2 g-1 for superparamagnetic NiFe2O4, respectively. Efficient oxidation was observed due to the synergized effect of nickel hydroxide (bronsted base) on Lewis center (Fe) of the nanocatalyst. Catalyst recycling experiments revealed that the ultrasmall nanocatalyst can be easily recovered by external magnet and applied for nearly complete oxidation of alcohols for at least five successive cycles. Furthermore, the nickel hydroxide functionalised ultrasmall nanocatalyst exhibited higher efficiency for benzyl alcohol oxidation compared to Ni(OH)2, bare MnFe2O4 and NiFe2O4. Higher conversion rate was observed for nickel hydroxide functionalised NiFe2O4 compared to MnFe2O4. Ultrasmall magnetic nickel hydroxide functionalised nanocatalyst showed environmental friendly, greener route for the oxidation of alcohols without significant loss in activity and selectivity within successive runs.

  19. Recycling Lithium Carbonate/Lithium Hydroxide Waste

    NASA Technical Reports Server (NTRS)

    Flowers, J.; Flowers, J.

    1983-01-01

    Hazardous waste disposal problem eliminated by regeneration. Li2CO3/ LiOH recycling process relies on low solubility of alkali carbonates in corresponding hydroxides. Li2CO3 precipitate calcined to LI2O, then rehydrated LiOH. Regeneration eliminates need to dispose caustic waste and uses less energy than simple calcination of entire waste mass.

  20. Study of nickel hydroxide electrodes. 2: Oxidation products of nickel (2) hydroxides

    NASA Technical Reports Server (NTRS)

    Bode, H.; Demelt, K.; White, J.

    1986-01-01

    Pure phases of some oxidized Ni oxides were prepared galvanimetrically with the Ni(2) hydroxide electrode of an alkaline battery. The crystallographic data of these phases, their chemical behavior, and conditions of transition were studied.

  1. 21 CFR 73.1010 - Alumina (dried aluminum hydroxide).

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Alumina (dried aluminum hydroxide). 73.1010... GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1010 Alumina (dried aluminum hydroxide). (a) Identity. (1) The color additive alumina (dried aluminum hydroxide) is a white,...

  2. 21 CFR 73.1010 - Alumina (dried aluminum hydroxide).

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Alumina (dried aluminum hydroxide). 73.1010... GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1010 Alumina (dried aluminum hydroxide). (a) Identity. (1) The color additive alumina (dried aluminum hydroxide) is a white,...

  3. 21 CFR 73.1010 - Alumina (dried aluminum hydroxide).

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Alumina (dried aluminum hydroxide). 73.1010... GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1010 Alumina (dried aluminum hydroxide). (a) Identity. (1) The color additive alumina (dried aluminum hydroxide) is a white,...

  4. 21 CFR 73.1010 - Alumina (dried aluminum hydroxide).

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Alumina (dried aluminum hydroxide). 73.1010... GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1010 Alumina (dried aluminum hydroxide). (a) Identity. (1) The color additive alumina (dried aluminum hydroxide) is a white,...

  5. 21 CFR 73.1010 - Alumina (dried aluminum hydroxide).

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Alumina (dried aluminum hydroxide). 73.1010... GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1010 Alumina (dried aluminum hydroxide). (a) Identity. (1) The color additive alumina (dried aluminum hydroxide) is a white,...

  6. 40 CFR 721.10504 - Surface modified magnesium hydroxide (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Surface modified magnesium hydroxide... Specific Chemical Substances § 721.10504 Surface modified magnesium hydroxide (generic). (a) Chemical... as surface modified magnesium hydroxide (PMN P-06-682) is subject to reporting under this section...

  7. 40 CFR 721.10504 - Surface modified magnesium hydroxide (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Surface modified magnesium hydroxide... Specific Chemical Substances § 721.10504 Surface modified magnesium hydroxide (generic). (a) Chemical... as surface modified magnesium hydroxide (PMN P-06-682) is subject to reporting under this section...

  8. 21 CFR 872.3250 - Calcium hydroxide cavity liner.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Calcium hydroxide cavity liner. 872.3250 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3250 Calcium hydroxide cavity liner. (a) Identification. A calcium hydroxide cavity liner is a device material intended to be applied to the interior of...

  9. 21 CFR 872.3250 - Calcium hydroxide cavity liner.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Calcium hydroxide cavity liner. 872.3250 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3250 Calcium hydroxide cavity liner. (a) Identification. A calcium hydroxide cavity liner is a device material intended to be applied to the interior of...

  10. 21 CFR 872.3250 - Calcium hydroxide cavity liner.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Calcium hydroxide cavity liner. 872.3250 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3250 Calcium hydroxide cavity liner. (a) Identification. A calcium hydroxide cavity liner is a device material intended to be applied to the interior of...

  11. 40 CFR 721.4600 - Recovered metal hydroxide.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Recovered metal hydroxide. 721.4600... Substances § 721.4600 Recovered metal hydroxide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a recovered metal hydroxide (PMN...

  12. 40 CFR 721.4600 - Recovered metal hydroxide.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Recovered metal hydroxide. 721.4600... Substances § 721.4600 Recovered metal hydroxide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a recovered metal hydroxide (PMN...

  13. 40 CFR 721.4600 - Recovered metal hydroxide.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Recovered metal hydroxide. 721.4600... Substances § 721.4600 Recovered metal hydroxide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a recovered metal hydroxide (PMN...

  14. 40 CFR 721.4600 - Recovered metal hydroxide.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Recovered metal hydroxide. 721.4600... Substances § 721.4600 Recovered metal hydroxide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a recovered metal hydroxide (PMN...

  15. 40 CFR 721.4600 - Recovered metal hydroxide.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Recovered metal hydroxide. 721.4600... Substances § 721.4600 Recovered metal hydroxide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a recovered metal hydroxide (PMN...

  16. 21 CFR 73.2326 - Chromium hydroxide green.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Chromium hydroxide green. 73.2326 Section 73.2326... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2326 Chromium hydroxide green. (a) Identity and specifications.The color additive chromium hydroxide green shall conform in identity and specifications to...

  17. 21 CFR 73.1326 - Chromium hydroxide green.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Chromium hydroxide green. 73.1326 Section 73.1326... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1326 Chromium hydroxide green. (a) Identity. (1) The color additive chromium hydroxide green is principally hydrated chromic sesquioxide...

  18. 21 CFR 73.2326 - Chromium hydroxide green.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Chromium hydroxide green. 73.2326 Section 73.2326... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2326 Chromium hydroxide green. (a) Identity and specifications.The color additive chromium hydroxide green shall conform in identity and specifications to...

  19. 21 CFR 73.1326 - Chromium hydroxide green.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Chromium hydroxide green. 73.1326 Section 73.1326... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1326 Chromium hydroxide green. (a) Identity. (1) The color additive chromium hydroxide green is principally hydrated chromic sesquioxide...

  20. An empirical model to estimate density of sodium hydroxide solution: An activator of geopolymer concretes

    NASA Astrophysics Data System (ADS)

    Rajamane, N. P.; Nataraja, M. C.; Jeyalakshmi, R.; Nithiyanantham, S.

    2016-02-01

    Geopolymer concrete is zero-Portland cement concrete containing alumino-silicate based inorganic polymer as binder. The polymer is obtained by chemical activation of alumina and silica bearing materials, blast furnace slag by highly alkaline solutions such as hydroxide and silicates of alkali metals. Sodium hydroxide solutions of different concentrations are commonly used in making GPC mixes. Often, it is seen that sodium hydroxide solution of very high concentration is diluted with water to obtain SHS of desired concentration. While doing so it was observed that the solute particles of NaOH in SHS tend to occupy lower volumes as the degree of dilution increases. This aspect is discussed in this paper. The observed phenomenon needs to be understood while formulating the GPC mixes since this influences considerably the relationship between concentration and density of SHS. This paper suggests an empirical formula to relate density of SHS directly to concentration expressed by w/w.

  1. A facile hydrothermal approach to the synthesis of nanoscale rare earth hydroxides

    NASA Astrophysics Data System (ADS)

    Li, Chengyin; Liu, Hui; Yang, Jun

    2015-03-01

    Nanosized rare earth (RE) hydroxides including La(OH)3, Nd(OH)3, Pr(OH)3, Sm(OH)3, Gd(OH)3, and Er(OH)3 with rod-like morphology are fabricated via a convenient hydrothermal approach. This strategy calls for the first preparation of metal complexes between RE precursors and dodecylamine (DDA) in water/ethanol mixture at room temperature and subsequent thermal decomposition at elevated temperature. The influence of reaction time and water/ethanol volume ratios on the morphology and size of as-prepared RE hydroxides are investigated. CeO2 nanoparticles with spherical shape could be directly obtained by hydrothermal treatment of complexes formed between Ce precursors and DDA. In addition, by further calcinating the RE hydroxides at high temperature in air, RE oxide nanorods could be readily produced.

  2. Direct laser pruning of CdS(x)Se1-x nanobelts en route to a multicolored pattern with controlled functionalities.

    PubMed

    Lu, Junpeng; Lim, Xiaodai; Zheng, Minrui; Mhaisalkar, Subodh G; Sow, Chorng-Haur

    2012-09-25

    CdS(x)Se(1-x) nanobelts are interesting nanostructured materials with a tunable band gap from 1.7 to 2.4 eV depending on the nanobelts' stoichiometry. On the basis of their chemical compositions, these nanobelts give out strong photoluminescence with unique color. In this work, we demonstrate that a direct focused laser beam irradiation was able to achieve localized modification of the chemical composition of the nanobelts. As a result, we could locally change the optical properties of these nanobelts. With a scanning laser beam, micropatterns with a wide range of fluorescence color could be created on a substrate covered with ternary nanobelts without a prepatterned mask. The laser modified nanobelts showed higher resistance to acid corrosion and these nanobelts exhibited more superior photoconductivity. The construction of micropatterns with functionality/color control within the sample would provide greater building blocks for photoelectronic applications.

  3. State alternative route designations

    SciTech Connect

    Not Available

    1989-07-01

    Pursuant to the Hazardous Materials Transportation Act (HMTA), the Department of Transportation (DOT) has promulgated a comprehensive set of regulations regarding the highway transportation of high-level radioactive materials. These regulations, under HM-164 and HM-164A, establish interstate highways as the preferred routes for the transportation of radioactive materials within and through the states. The regulations also provide a methodology by which a state may select alternative routes. First,the state must establish a state routing agency,'' defined as an entity authorized to use the state legal process to impose routing requirements on carriers of radioactive material (49 CFR 171.8). Once identified, the state routing agency must select routes in accordance with Large Quantity Shipments of Radioactive Materials or an equivalent routing analysis. Adjoining states and localities should be consulted on the impact of proposed alternative routes as a prerequisite of final route selection. Lastly, the states must provide written notice of DOT of any alternative route designation before the routes are deemed effective.

  4. State alternative route designations

    SciTech Connect

    Not Available

    1989-07-01

    Pursuant to the Hazardous Materials Transportation Act (HMTA), the Department of Transportation (DOT) has promulgated a comprehensive set of regulations regarding the highway transportation of high-level radioactive materials. These regulations, under HM-164 and HM-164A, establish interstate highways as the preferred routes for the transportation of radioactive materials within and through the states. The regulations also provide a methodology by which a state may select alternative routes. First,the state must establish a ``state routing agency,`` defined as an entity authorized to use the state legal process to impose routing requirements on carriers of radioactive material (49 CFR 171.8). Once identified, the state routing agency must select routes in accordance with Large Quantity Shipments of Radioactive Materials or an equivalent routing analysis. Adjoining states and localities should be consulted on the impact of proposed alternative routes as a prerequisite of final route selection. Lastly, the states must provide written notice of DOT of any alternative route designation before the routes are deemed effective.

  5. Nanoimprint-assisted directed self-assembly of low-molecular weight block copolymers: a route for 3D and multilevel nanostructures

    NASA Astrophysics Data System (ADS)

    Simão, C.; Khunsin, W.; Kehagias, N.; Francone, A.; Zelsmann, M.; Morris, M. A.; Sotomayor Torres, C. M.

    2014-06-01

    Multilevel controllable nanoimprint driven molecular orientation has been obtained in thin films of block copolymer polystyrene-b-polyethylene oxide( PS-b-PEO) by means of solvent vapours assisted nanoimprint lithography (SAIL). The NIL setup using solvent vapours was capable of imprinting nanoscale features over a large area and simultaneously annealing PS-b-PEO thin films. A line pattern stamp was replicated in the BCP film in over a large area with a high resolution registry, and was also observed that the PS-b-PEO film exhibited microphase segregation in the residual layer exhibits a nanodot array from showing hexagonally packed PEO dots in the PS matrix, with a diameter of 20 nm with 40 nm pitch. The order of the hexagonally arranged nanodot lattice seen in the nanodots array was quantified from SEM images using by the opposite partner method from SEM images analysis and compared with to conventionally solvent annealed BCP films, demonstrating an improvement of the ordering of up to 50%. Grazing-incidence small-angle X-ray scattering (GISAXS) study demonstrates the excellent fidelity of the pattern transfer and confirms the periodicity of the BCP in the mesas. In addition, applying the SAIL methodology to BCP thin films in nanopatterned silsequioxane substrates, it was possible to obtain multilevel structures decorated with the BCP microphase segregation. The SAIL technique is a versatile and robust platform to obtain complex high density periodic nanostructures, particularly for second generation block copolymers directed self-assembly.

  6. Understanding Arsenate Reaction Kinetics with Ferric Hydroxides

    PubMed Central

    Farrell, James; Chaudhary, Binod K.

    2015-01-01

    Understanding arsenic reactions with ferric hydroxides is important in understanding arsenic transport in the environment and in designing systems for removing arsenic from potable water. Many experimental studies have shown that the kinetics of arsenic adsorption on ferric hydroxides is biphasic, where a fraction of the arsenic adsorption occurs on a time scale of seconds while full equilibrium may require weeks to attain. This research employed density functional theory modeling in order to understand the mechanisms contributing to biphasic arsenic adsorption kinetics. The reaction energies and activation barriers for three modes of arsenate adsorption to ferric hydroxides were calculated. Gibbs free energies of reaction depended on the net charge of the complexes, which is a function of the system pH value. Physical adsorption of arsenate to ferric hydroxide proceeded with no activation barrier, with Gibbs free energies of reaction ranging from −21 to −58 kJ/mol. The highest Gibbs free energies of reaction for physical adsorption resulted from negative charge assisted hydrogen bonding between H atoms on the ferric hydroxide and O atoms in arsenate. The conversion of physically adsorbed arsenate into monodentate surface complexes had Gibbs free energies of activation ranging from 62 to 73 kJ/mol, and Gibbs free energies of reaction ranging from −23 to −38 kJ/mol. The conversion of monodentate surface complexes to bidentate, binuclear complexes had Gibbs free energies of activation ranging from 79 to 112 kJ/mol, and Gibbs free energies of reaction ranging from −11 to −55 kJ/mol. For release of arsenate from uncharged bidentate complexes, energies of activation as high as 167 kJ/mol were encountered. Increasingly negative charges on the complexes lowered the activation barriers for desorption of arsenate, and in complexes with −2 charges, the highest activation barrier was 65 kJ/mol. This study shows that the slow kinetics associated with arsenic

  7. Predicting As removal during metal hydroxide precipitation

    SciTech Connect

    McNeill, L.S.; Edwards, M.

    1997-01-01

    A simplified isotherm is described that can predict the extent of arsenate removal at drinking water utilities practicing coagulation or iron-manganese (Fe-Mn) removal. If all possible sources of particulate iron and aluminum hydroxide present in the system are accounted for, the model predicts arsenic (As) removal to within {+-}13 percent (90 percent confidence) for Fe coagulation at pH 6.5--8 and alum coagulation at pH < 7.6. Analysis of full-scale treatment data suggests that colloidal aluminum (Al) flocs with sorbed arsenate [As(V)] may pass through filters, thereby decreasing overall As removal efficiency. Thus, Al solubility and particle stability must be minimized to improve As removal. If stability and solubility of aluminum hydroxide flocs are not a problem, alum and Fe coagulants have nearly equal capacity for sorbing As(V). Survey results also demonstrate the importance of particulate As.

  8. Routing protocols in wireless sensor networks.

    PubMed

    Villalba, Luis Javier García; Orozco, Ana Lucila Sandoval; Cabrera, Alicia Triviño; Abbas, Cláudia Jacy Barenco

    2009-01-01

    The applications of wireless sensor networks comprise a wide variety of scenarios. In most of them, the network is composed of a significant number of nodes deployed in an extensive area in which not all nodes are directly connected. Then, the data exchange is supported by multihop communications. Routing protocols are in charge of discovering and maintaining the routes in the network. However, the appropriateness of a particular routing protocol mainly depends on the capabilities of the nodes and on the application requirements. This paper presents a review of the main routing protocols proposed for wireless sensor networks. Additionally, the paper includes the efforts carried out by Spanish universities on developing optimization techniques in the area of routing protocols for wireless sensor networks. PMID:22291515

  9. Routing Protocols in Wireless Sensor Networks

    PubMed Central

    Villalba, Luis Javier García; Orozco, Ana Lucila Sandoval; Cabrera, Alicia Triviño; Abbas, Cláudia Jacy Barenco

    2009-01-01

    The applications of wireless sensor networks comprise a wide variety of scenarios. In most of them, the network is composed of a significant number of nodes deployed in an extensive area in which not all nodes are directly connected. Then, the data exchange is supported by multihop communications. Routing protocols are in charge of discovering and maintaining the routes in the network. However, the appropriateness of a particular routing protocol mainly depends on the capabilities of the nodes and on the application requirements. This paper presents a review of the main routing protocols proposed for wireless sensor networks. Additionally, the paper includes the efforts carried out by Spanish universities on developing optimization techniques in the area of routing protocols for wireless sensor networks. PMID:22291515

  10. Pressure-induced decomposition of indium hydroxide.

    PubMed

    Gurlo, Aleksander; Dzivenko, Dmytro; Andrade, Miria; Riedel, Ralf; Lauterbach, Stefan; Kleebe, Hans-Joachim

    2010-09-15

    A static pressure-induced decomposition of indium hydroxide into metallic indium that takes place at ambient temperature is reported. The lattice parameter of c-In(OH)(3) decreased upon compression from 7.977(2) to approximately 7.45 A at 34 GPa, corresponding to a decrease in specific volume of approximately 18%. Fitting the second-order Birch-Murnaghan equation of state to the obtained compression data gave a bulk modulus of 99 +/- 3 GPa for c-In(OH)(3). The c-In(OH)(3) crystals with a size of approximately 100 nm are comminuted upon compression, as indicated by the grain-size reduction reflected in broadening of the diffraction reflections and the appearance of smaller (approximately 5 nm) incoherently oriented domains in TEM. The rapid decompression of compressed c-In(OH)(3) leads to partial decomposition of indium hydroxide into metallic indium, mainly as a result of localized stress gradients caused by relaxation of the highly disordered indium sublattice in indium hydroxide. This partial decomposition of indium hydroxide into metallic indium is irreversible, as confirmed by angle-dispersive X-ray diffraction, transmission electron microscopy imaging, Raman scattering, and FTIR spectroscopy. Recovered c-In(OH)(3) samples become completely black and nontransparent and show typical features of metals, i.e., a falling absorption in the 100-250 cm(-1) region accompanied by a featureless spectrum in the 250-2500 cm(-1) region in the Raman spectrum and Drude-like absorption of free electrons in the region of 4000-8000 cm(-1) in the FTIR spectrum. These features were not observed in the initial c-In(OH)(3), which is a typical white wide-band-gap semiconductor.

  11. Sodium hydroxide permethylation of heparin disaccharides.

    PubMed

    Heiss, Christian; Wang, Zhirui; Azadi, Parastoo

    2011-03-30

    Permethylation is a valuable and widely used tool for the mass spectrometry of carbohydrates, improving sensitivity and fragmentation and increasing the amount of information that can be obtained from tandem mass spectrometric experiments. Permethylation of most glycans is easily performed with sodium hydroxide and iodomethane in dimethyl sulfoxide (DMSO). However, permethylation has not been widely used in the mass spectrometry of glycosaminoglycan (GAG) oligosaccharides, partly because it has required the use of the difficult Hakomori method employing the methylsulfinylmethanide ('dimsyl') base, which has to be made in a tedious process. Additionally, the Hakomori method is not as effective as the sodium hydroxide method in making fully methylated derivatives. A further problem in the permethylation of highly sulfated oligosaccharides is their limited solubility in DMSO. This paper describes the use of the triethylammonium counterion to overcome this problem, as well as the application of the sodium hydroxide method to make permethylated heparin disaccharides and their workup to yield fully methylated disaccharides for electrospray ionization mass spectrometry. The ease, speed, and effectiveness of the described methodology should open up permethylation of GAG oligosaccharides to a wider circle of mass spectrometrists and enable them to develop further derivatization schemes in the effort to rapidly elucidate the structure of these important molecules. Permethylation may also provide new ways of separating GAG oligosaccharides in LC/MS, their increased hydrophobicity making them amenable for reversed-phase chromatography without the need for ion pairing reagents.

  12. Contact Graph Routing

    NASA Technical Reports Server (NTRS)

    Burleigh, Scott C.

    2011-01-01

    Contact Graph Routing (CGR) is a dynamic routing system that computes routes through a time-varying topology of scheduled communication contacts in a network based on the DTN (Delay-Tolerant Networking) architecture. It is designed to enable dynamic selection of data transmission routes in a space network based on DTN. This dynamic responsiveness in route computation should be significantly more effective and less expensive than static routing, increasing total data return while at the same time reducing mission operations cost and risk. The basic strategy of CGR is to take advantage of the fact that, since flight mission communication operations are planned in detail, the communication routes between any pair of bundle agents in a population of nodes that have all been informed of one another's plans can be inferred from those plans rather than discovered via dialogue (which is impractical over long one-way-light-time space links). Messages that convey this planning information are used to construct contact graphs (time-varying models of network connectivity) from which CGR automatically computes efficient routes for bundles. Automatic route selection increases the flexibility and resilience of the space network, simplifying cross-support and reducing mission management costs. Note that there are no routing tables in Contact Graph Routing. The best route for a bundle destined for a given node may routinely be different from the best route for a different bundle destined for the same node, depending on bundle priority, bundle expiration time, and changes in the current lengths of transmission queues for neighboring nodes; routes must be computed individually for each bundle, from the Bundle Protocol agent's current network connectivity model for the bundle s destination node (the contact graph). Clearly this places a premium on optimizing the implementation of the route computation algorithm. The scalability of CGR to very large networks remains a research topic

  13. Layered double hydroxide stability. 1. Relative stabilities of layered double hydroxides and their simple counterparts

    NASA Technical Reports Server (NTRS)

    Boclair, J. W.; Braterman, P. S.

    1999-01-01

    Solutions containing di- and trivalent metal chlorides [M(II) = Mg2+, Zn2+, Co2+, Ni2+, Mn2+; M(III) = Al3+, Fe3+] were titrated with NaOH to yield hydrotalcite-like layered double hydroxides (LDH), [[M(II)]1-x[M(III)]x(OH)2][Cl]x yH2O, by way of M(III) hydroxide/hydrous oxide intermediates. Analysis of the resultant titration curves yields nominal solubility constants for the LDH. The corresponding LDH stabilities are in the order Mg < Mn < Co approximately Ni < Zn for M(II) and Al < Fe for M(III). The stability of LDH relative to the separate metal hydroxides/hydrous oxides is discussed.

  14. Respiration of metal (hydr)oxides by Shewanella and Geobacter: a key role for multihaem c-type cytochromes

    SciTech Connect

    Shi, Liang; Squier, Thomas C.; Zachara, John M.; Fredrickson, Jim K.

    2007-07-01

    Dissimilatory reduction of metal (e.g. Fe, Mn) (hydr)oxides represents a challenge for microorganisms, as their cell envelopes are impermeable to metal (hydr)oxides that are poorly soluble in water. To overcome this physical barrier, the Gram-negative bacteria Shewanella oneidensis MR-1 and Geobactersulfurreducens have developed electron transfer (ET) strategies that require multihaem c-type cytochromes (c-Cyts). In S. oneidensis MR-1, multihaem c-Cyts CymA and MtrA are believed to transfer electrons from the inner membrane quinone/quinol pool through the periplasm to the outer membrane. The type II secretion system of S. oneidensis MR-1 has been implicated in the reduction of metal (hydr)oxides, most likely by translocating decahaem c-Cyts MtrC and OmcA across outer membrane to the surface of bacterial cells where they form a protein complex. The extracellular MtrC and OmcA can directly reduce solid metal (hydr)oxides. Likewise, outer membrane multihaem c-Cyts OmcE and OmcS of G. sulfurreducens are suggested to transfer electrons from outer membrane to type IV pili that are hypothesized to relay the electrons to solid metal (hydr)oxides. Thus, multihaem c-Cyts play critical roles in S. oneidensis MR-1-and G. sulfurreducens-mediated dissimilatory reduction of solid metal (hydr)oxides by facilitating ET across the bacterial cell envelope.

  15. Application of the SCC-DFTB method to hydroxide water clusters and aqueous hydroxide solutions.

    PubMed

    Choi, Tae Hoon; Liang, Ruibin; Maupin, C Mark; Voth, Gregory A

    2013-05-01

    The self-consistent charge density functional tight binding (SCC-DFTB) method has been applied to hydroxide water clusters and a hydroxide ion in bulk water. To determine the impact of various implementations of SCC-DFTB on the energetics and dynamics of a hydroxide ion in gas phase and condensed phase, the DFTB2, DFTB2-γ(h), DFTB2-γ(h)+gaus, DFTB3-diag, DFTB3-diag+gaus, DFTB3-Full+gaus, and DFTB3-3OB implementations have been tested. Energetic stabilities for small hydroxide clusters, OH(-)(H2O)n, where n = 4-7, are inconsistent with the results calculated with the B3LYP and second order Møller-Plesset (MP2) levels of ab initio theory. The condensed phase simulations, OH(-)(H2O)127, using the DFTB2, DFTB2-γ(h), DFTB2-γ(h)+gaus, DFTB3-diag, DFTB3-diag+gaus, DFTB3-Full+gaus and DFTB3-3OB methods are compared to Car-Parrinello molecular dynamics (CPMD) simulations using the BLYP functional. The SCC-DFTB method including a modified O-H repulsive potential and the third order correction (DFTB3-diag/Full+gaus) is shown to poorly reproduce the CPMD computational results, while the DFTB2 and DFTB2-γ(h) method somewhat more closely describe the structural and dynamical nature of the hydroxide ion in condensed phase. The DFTB3-3OB outperforms the MIO parameter set but is no more accurate than DFTB2. It is also shown that the overcoordinated water molecules lead to an incorrect bulk water density and result in unphysical water void formation. The results presented in this paper point to serious drawbacks for various DFTB extensions and corrections for a hydroxide ion in aqueous environments. PMID:23566052

  16. A XAFS study of plain and composite iron(III) and chromium(III) hydroxides.

    PubMed

    Papassiopi, N; Pinakidou, F; Katsikini, M; Antipas, G S E; Christou, C; Xenidis, A; Paloura, E C

    2014-09-01

    Reduction of hexavalent Cr(VI) to the trivalent state is the common strategy for remediation of Cr(VI) contaminated waters and soils. In the presence of Fe the resulting compounds are usually mixed Fe(III)-Cr(III) phases, while, under iron-free conditions, reduction leads to formation of plain Cr(III) hydroxides. Environmental stability of these compounds depends on their structure and is important to understand how different precipitation conditions affect the local atomic order of resulting compounds and thus their long term stability. In current study, typical Cr(VI) environmental remediation products, i.e. plain and mixed Fe(III)-Cr(III) hydroxides, were synthesized by hydrolysis and redox reactions and their structure was studied by X ray diffraction and X ray absorption fine structure techniques. Plain Cr(III) hydroxide was found to correspond to the molecular formula Cr(OH)3·3H2O and was identified as crystalline in XRD. However, the same compound when examined by EXAFS did not exhibit any clear local order in the range of EXAFS detectable distances, i.e. between 0 and 5Å. Namely, EXAFS spectroscopy detected only contribution from the first nearest neighboring (Cr-O) shell, suggesting that CrO6 octahedra interconnection is loose, in accordance with the suggested anti-bayerite structure of this compound. Mixed Fe(III)-Cr(III) systems resembled 2-line ferrihydrite irrespective of the synthesis route. Analysis of Fe-K-EXAFS and Cr-K-EXAFS spectra indicated that FeO6 octahedra are bonded by sharing both edges and corners, while CrO6 octahedra seem to prefer edge sharing linkage. EXAFS data also suggest that Fe-Cr hydroxide produced by hydrolysis presents a better arrangement of CrO6 octahedra compared to the redox product.

  17. 49 CFR 356.9 - Elimination of routing restrictions-regular route carriers.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... operations under paragraph (a) of this section may serve points on, and within one airline mile of, an... direction as the carrier's authorized service route and (ii) Is wholly within 25 airline miles of...

  18. 49 CFR 356.9 - Elimination of routing restrictions-regular route carriers.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... operations under paragraph (a) of this section may serve points on, and within one airline mile of, an... direction as the carrier's authorized service route and (ii) Is wholly within 25 airline miles of...

  19. Hydroxide as general base in the saponification of ethyl acetate.

    PubMed

    Mata-Segreda, Julio F

    2002-03-13

    The second-order rate constant for the saponification of ethyl acetate at 30.0 degrees C in H(2)O/D(2)O mixtures of deuterium atom fraction n (a proton inventory experiment) obeys the relation k(2)(n) = 0.122 s(-1) M(-1) (1 - n + 1.2n) (1 - n + 0.48n)/(1 - n + 1.4n) (1 - n + 0.68n)(3). This result is interpreted as a process where formation of the tetrahedral intermediate is the rate-determining step and the transition-state complex is formed via nucleophilic interaction of a water molecule with general-base assistance from hydroxide ion, opposite to the direct nucleophilic collision commonly accepted. This mechanistic picture agrees with previous heavy-atom kinetic isotope effect data of Marlier on the alkaline hydrolysis of methyl formate.

  20. Automatic routing module

    NASA Technical Reports Server (NTRS)

    Malin, Janice A.

    1987-01-01

    Automatic Routing Module (ARM) is a tool to partially automate Air Launched Cruise Missile (ALCM) routing. For any accessible launch point or target pair, ARM creates flyable routes that, within the fidelity of the models, are optimal in terms of threat avoidance, clobber avoidance, and adherence to vehicle and planning constraints. Although highly algorithmic, ARM is an expert system. Because of the heuristics applied, ARM generated routes closely resemble manually generated routes in routine cases. In more complex cases, ARM's ability to accumulate and assess threat danger in three dimensions and trade that danger off with the probability of ground clobber results in the safest path around or through difficult areas. The tools available prior to ARM did not provide the planner with enough information or present it in such a way that ensured he would select the safest path.

  1. Properties of Air Traffic Conflicts for Free and Structured Routing

    NASA Technical Reports Server (NTRS)

    Bilimoria, Karl D.; Lee, Hilda Q.

    2001-01-01

    This paper analyzes the properties of air traffic conflicts in a future free routing system against those in the current structured routing system. Simulation of en route air traffic operations (above 18,000 ft) over the contiguous United States for a 24-hour period, constructed with initial conditions from actual air traffic data, were conducted using the Future ATM Concepts Evaluation Tool (FACET). Free routes were modeled as great circle (direct) routes from origin to destination, and structured routes were derived from actual flight plans along the current system of air routes. The conflict properties analyzed in this study include: (1) Total number of conflicts; (2) Distributions of key conflict parameters; and, (3) Categorization of conflicts into independent conflicts and two types of interacting conflicts. Preliminary results (for Denver Center traffic) indicate that conflict properties in a free routing system are different from those in the current structured routing system. In particular, a free routing system has significantly fewer conflicts, involving a correspondingly smaller number of aircraft, compared to the current structured routing system. Additionally, the conflict parameter distributions indicate that free routing conflicts are less intrusive than structured routing conflicts, and would therefore require small trajectory deviations for resolution.

  2. Mechano-hydrothermal synthesis of Mg{sub 2}Al–NO{sub 3} layered double hydroxides

    SciTech Connect

    Zhang, Fengrong; Du, Na; Song, Shue; Liu, Jianqiang; Hou, Wanguo

    2013-10-15

    A mechano-hydrothermal method was developed to synthesize Mg{sub 2}Al–NO{sub 3} layered double hydroxide (LDH) from MgO, Al{sub 2}O{sub 3} and NaNO{sub 3} as starting materials. A two-step synthesis was conducted, that is, a mixture of MgO and Al{sub 2}O{sub 3} was milled for 1 h, followed by hydrothermal treatment with NaNO{sub 3} solution. The resulting LDHs were characterized by X-ray diffraction, transmission electron microscopy, scanning electron microscopy, Fourier transform infrared and elemental analyses. Pre-milling played a key role in the LDH formation during subsequent hydrothermal treatment. The process is advantageous in terms of low reaction temperature and short reaction time compared with the conventional hydrothermal method, and the target products are of high crystallinity, good dispersion and regular shape compared with the conventional mechanochemical method. - Graphical abstract: The novel mechano-hydrothermal route to synthesize LDH has advantages in low reaction temperature and short reaction time, and the target product was of high crystallinity, good dispersion and regular shape. Display Omitted - Highlights: • A mechano-hydrothermal route was developed for layered double hydroxide synthesis. • Synthesis could be achieved at low temperature and in a short time. • Resulting layered double hydroxide samples were well dispersed and of regular shape. • A dissolution–recrystallization mechanism was proposed for the formation process.

  3. Infrared band intensities in ammonium hydroxide and ammonium salts

    NASA Technical Reports Server (NTRS)

    Sethna, P. P.; Downing, H. D.; Pinkley, L. W.; Williams, D.

    1978-01-01

    We have applied Kramers-Kronig analysis to reflection spectra to determine the optical constants of ammonium hydroxide and of aqueous solutions of ammonium chloride and bromide. From considerations of the absorption indices k(nu) we conclude that ammonium hydroxide consists of a solution of NH3 in water, in which NH3 molecules are hydrogen bonded to neighboring water molecules. The spectrum of ammonium hydroxide differs from the spectra of ammonium salts, in which bands characteristic of NH4(+) ions are prominent. The existence of ammonium hydroxide as an aerosol in planetary atmospheres is briefly discussed

  4. The alpha-form of the hydroxides of bivalent metals

    NASA Technical Reports Server (NTRS)

    Feitknecht, W.

    1984-01-01

    X-ray analyses were made of the hydroxides of the bivalent metals. The freshly pptd. hydroxide is usually in the alpha-form, which on standing is converted to another form or other forms. The alpha and c grating dimensions of the alpha-form and the C6-type of Co, Zn, C, Co-Zn and Ni-Zn hydroxides are tabulated. Ni hydroxide does not exhibit an alpha-form. The alpha-Co(OH)2, the blue form, is stabilized by sugar or by the higher alcohols: these compounds do not stabilize alpha-Zn(OH)2.

  5. Photoactive oriented films of layered double hydroxides.

    PubMed

    Lang, Kamil; Kubát, Pavel; Mosinger, Jirí; Bujdák, Juraj; Hof, Martin; Janda, Pavel; Sýkora, Jan; Iyi, Nobuo

    2008-08-14

    The treatment of nano-ordered oriented films of layered double hydroxide (LDH) with dodecyl sulfate increased the interlayer distance from 0.4 to 1.96 nm, which allowed the intercalation of 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin (TPPS). The re-stacking of separated layers and the rebuilding of crystals oriented parallel to the surface of quartz slides was confirmed by X-ray diffraction and atomic force microscopy. The hybrid films contained homogeneously distributed porphyrin molecules with preserved photophysical properties such as fluorescence, triplet state formation, and energy transfer, thus forming singlet oxygen.

  6. Electrocatalysis and electroanalysis of nickel, its oxides, hydroxides and oxyhydroxides toward small molecules.

    PubMed

    Miao, Yuqing; Ouyang, Lei; Zhou, Shilin; Xu, Lina; Yang, Zhuoyuan; Xiao, Mingshu; Ouyang, Ruizhuo

    2014-03-15

    The electrocatalysis toward small molecules, especially small organic compounds, is of importance in a variety of areas. Nickel based materials such as nickel, its oxides, hydroxides as well as oxyhydroxides exhibit excellent electrocatalysis performances toward many small molecules, which are widely used for fuel cells, energy storage, organic synthesis, wastewater treatment, and electrochemical sensors for pharmaceutical, medical, food or environmental analysis. Their electrocatalytic mechanisms are proposed from three aspects such as Ni(OH)2/NiOOH mediated electrolysis, direct electrocatalysis of Ni(OH)2 or NiOOH. Under exposure to air or aqueous solution, two distinct layers form on the Ni surface with a Ni hydroxide layer at the air-oxide interface and an oxide layer between the metal substrate and the outer hydroxide layer. The transformation from nickel or its oxides to hydroxides or oxyhydroxides could be further speeded up in the strong alkaline solution under the cyclic scanning at relatively high positive potential. The redox transition between Ni(OH)2 and NiOOH is also contributed to the electrocatalytic oxidation of Ni and its oxides toward small molecules in alkaline media. In addition, nickel based materials or nanomaterials, their preparations and applications are also overviewed here.

  7. Hydrated proton and hydroxide charge transfer at the liquid/vapor interface of water

    SciTech Connect

    Soniat, Marielle; Rick, Steven W.; Kumar, Revati

    2015-07-28

    The role of the solvated excess proton and hydroxide ions in interfacial properties is an interesting scientific question with applications in a variety of aqueous behaviors. The role that charge transfer (CT) plays in interfacial behavior is also an unsettled question. Quantum calculations are carried out on clusters of water with an excess proton or a missing proton (hydroxide) to determine their CT. The quantum results are applied to analysis of multi-state empirical valence bond trajectories. The polyatomic nature of the solvated excess proton and hydroxide ion results in directionally dependent CT, depending on whether a water molecule is a hydrogen bond donor or acceptor in relation to the ion. With polyatomic molecules, CT also depends on the intramolecular bond distances in addition to intermolecular distances. The hydrated proton and hydroxide affect water’s liquid/vapor interface in a manner similar to monatomic ions, in that they induce a hydrogen-bonding imbalance at the surface, which results in charged surface waters. This hydrogen bond imbalance, and thus the charged waters at the surface, persists until the ion is at least 10 Å away from the interface.

  8. Understanding individual routing behaviour.

    PubMed

    Lima, Antonio; Stanojevic, Rade; Papagiannaki, Dina; Rodriguez, Pablo; González, Marta C

    2016-03-01

    Knowing how individuals move between places is fundamental to advance our understanding of human mobility (González et al. 2008 Nature 453, 779-782. (doi:10.1038/nature06958)), improve our urban infrastructure (Prato 2009 J. Choice Model. 2, 65-100. (doi:10.1016/S1755-5345(13)70005-8)) and drive the development of transportation systems. Current route-choice models that are used in transportation planning are based on the widely accepted assumption that people follow the minimum cost path (Wardrop 1952 Proc. Inst. Civ. Eng. 1, 325-362. (doi:10.1680/ipeds.1952.11362)), despite little empirical support. Fine-grained location traces collected by smart devices give us today an unprecedented opportunity to learn how citizens organize their travel plans into a set of routes, and how similar behaviour patterns emerge among distinct individual choices. Here we study 92 419 anonymized GPS trajectories describing the movement of personal cars over an 18-month period. We group user trips by origin-destination and we find that most drivers use a small number of routes for their routine journeys, and tend to have a preferred route for frequent trips. In contrast to the cost minimization assumption, we also find that a significant fraction of drivers' routes are not optimal. We present a spatial probability distribution that bounds the route selection space within an ellipse, having the origin and the destination as focal points, characterized by high eccentricity independent of the scale. While individual routing choices are not captured by path optimization, their spatial bounds are similar, even for trips performed by distinct individuals and at various scales. These basic discoveries can inform realistic route-choice models that are not based on optimization, having an impact on several applications, such as infrastructure planning, routing recommendation systems and new mobility solutions. PMID:26962031

  9. Understanding individual routing behaviour.

    PubMed

    Lima, Antonio; Stanojevic, Rade; Papagiannaki, Dina; Rodriguez, Pablo; González, Marta C

    2016-03-01

    Knowing how individuals move between places is fundamental to advance our understanding of human mobility (González et al. 2008 Nature 453, 779-782. (doi:10.1038/nature06958)), improve our urban infrastructure (Prato 2009 J. Choice Model. 2, 65-100. (doi:10.1016/S1755-5345(13)70005-8)) and drive the development of transportation systems. Current route-choice models that are used in transportation planning are based on the widely accepted assumption that people follow the minimum cost path (Wardrop 1952 Proc. Inst. Civ. Eng. 1, 325-362. (doi:10.1680/ipeds.1952.11362)), despite little empirical support. Fine-grained location traces collected by smart devices give us today an unprecedented opportunity to learn how citizens organize their travel plans into a set of routes, and how similar behaviour patterns emerge among distinct individual choices. Here we study 92 419 anonymized GPS trajectories describing the movement of personal cars over an 18-month period. We group user trips by origin-destination and we find that most drivers use a small number of routes for their routine journeys, and tend to have a preferred route for frequent trips. In contrast to the cost minimization assumption, we also find that a significant fraction of drivers' routes are not optimal. We present a spatial probability distribution that bounds the route selection space within an ellipse, having the origin and the destination as focal points, characterized by high eccentricity independent of the scale. While individual routing choices are not captured by path optimization, their spatial bounds are similar, even for trips performed by distinct individuals and at various scales. These basic discoveries can inform realistic route-choice models that are not based on optimization, having an impact on several applications, such as infrastructure planning, routing recommendation systems and new mobility solutions.

  10. Routing Vehicles with Ants

    NASA Astrophysics Data System (ADS)

    Tan, Wen Fang; Lee, Lai Soon; Majid, Zanariah Abdul; Seow, Hsin Vonn

    Routing vehicles involve the design of an optimal set of routes for a fleet of vehicles to serve a number of customers with known demands. This research develops an Ant Colony Optimization for the vehicle routing with one central depot and identical vehicles. The procedure simulates the behavior of real ants that always find the shortest path between their nest and a food source through a form of communication, pheromone trail. Finally, preliminary results on the learning of the algorithm testing on benchmark data set will be presented in this paper.

  11. Protons and Hydroxide Ions in Aqueous Systems.

    PubMed

    Agmon, Noam; Bakker, Huib J; Campen, R Kramer; Henchman, Richard H; Pohl, Peter; Roke, Sylvie; Thämer, Martin; Hassanali, Ali

    2016-07-13

    Understanding the structure and dynamics of water's constituent ions, proton and hydroxide, has been a subject of numerous experimental and theoretical studies over the last century. Besides their obvious importance in acid-base chemistry, these ions play an important role in numerous applications ranging from enzyme catalysis to environmental chemistry. Despite a long history of research, many fundamental issues regarding their properties continue to be an active area of research. Here, we provide a review of the experimental and theoretical advances made in the last several decades in understanding the structure, dynamics, and transport of the proton and hydroxide ions in different aqueous environments, ranging from water clusters to the bulk liquid and its interfaces with hydrophobic surfaces. The propensity of these ions to accumulate at hydrophobic surfaces has been a subject of intense debate, and we highlight the open issues and challenges in this area. Biological applications reviewed include proton transport along the hydration layer of various membranes and through channel proteins, problems that are at the core of cellular bioenergetics. PMID:27314430

  12. Protons and Hydroxide Ions in Aqueous Systems.

    PubMed

    Agmon, Noam; Bakker, Huib J; Campen, R Kramer; Henchman, Richard H; Pohl, Peter; Roke, Sylvie; Thämer, Martin; Hassanali, Ali

    2016-07-13

    Understanding the structure and dynamics of water's constituent ions, proton and hydroxide, has been a subject of numerous experimental and theoretical studies over the last century. Besides their obvious importance in acid-base chemistry, these ions play an important role in numerous applications ranging from enzyme catalysis to environmental chemistry. Despite a long history of research, many fundamental issues regarding their properties continue to be an active area of research. Here, we provide a review of the experimental and theoretical advances made in the last several decades in understanding the structure, dynamics, and transport of the proton and hydroxide ions in different aqueous environments, ranging from water clusters to the bulk liquid and its interfaces with hydrophobic surfaces. The propensity of these ions to accumulate at hydrophobic surfaces has been a subject of intense debate, and we highlight the open issues and challenges in this area. Biological applications reviewed include proton transport along the hydration layer of various membranes and through channel proteins, problems that are at the core of cellular bioenergetics.

  13. A Survey on Underwater Acoustic Sensor Network Routing Protocols.

    PubMed

    Li, Ning; Martínez, José-Fernán; Meneses Chaus, Juan Manuel; Eckert, Martina

    2016-03-22

    Underwater acoustic sensor networks (UASNs) have become more and more important in ocean exploration applications, such as ocean monitoring, pollution detection, ocean resource management, underwater device maintenance, etc. In underwater acoustic sensor networks, since the routing protocol guarantees reliable and effective data transmission from the source node to the destination node, routing protocol design is an attractive topic for researchers. There are many routing algorithms have been proposed in recent years. To present the current state of development of UASN routing protocols, we review herein the UASN routing protocol designs reported in recent years. In this paper, all the routing protocols have been classified into different groups according to their characteristics and routing algorithms, such as the non-cross-layer design routing protocol, the traditional cross-layer design routing protocol, and the intelligent algorithm based routing protocol. This is also the first paper that introduces intelligent algorithm-based UASN routing protocols. In addition, in this paper, we investigate the development trends of UASN routing protocols, which can provide researchers with clear and direct insights for further research.

  14. A Survey on Underwater Acoustic Sensor Network Routing Protocols

    PubMed Central

    Li, Ning; Martínez, José-Fernán; Meneses Chaus, Juan Manuel; Eckert, Martina

    2016-01-01

    Underwater acoustic sensor networks (UASNs) have become more and more important in ocean exploration applications, such as ocean monitoring, pollution detection, ocean resource management, underwater device maintenance, etc. In underwater acoustic sensor networks, since the routing protocol guarantees reliable and effective data transmission from the source node to the destination node, routing protocol design is an attractive topic for researchers. There are many routing algorithms have been proposed in recent years. To present the current state of development of UASN routing protocols, we review herein the UASN routing protocol designs reported in recent years. In this paper, all the routing protocols have been classified into different groups according to their characteristics and routing algorithms, such as the non-cross-layer design routing protocol, the traditional cross-layer design routing protocol, and the intelligent algorithm based routing protocol. This is also the first paper that introduces intelligent algorithm-based UASN routing protocols. In addition, in this paper, we investigate the development trends of UASN routing protocols, which can provide researchers with clear and direct insights for further research. PMID:27011193

  15. A Survey on Underwater Acoustic Sensor Network Routing Protocols.

    PubMed

    Li, Ning; Martínez, José-Fernán; Meneses Chaus, Juan Manuel; Eckert, Martina

    2016-01-01

    Underwater acoustic sensor networks (UASNs) have become more and more important in ocean exploration applications, such as ocean monitoring, pollution detection, ocean resource management, underwater device maintenance, etc. In underwater acoustic sensor networks, since the routing protocol guarantees reliable and effective data transmission from the source node to the destination node, routing protocol design is an attractive topic for researchers. There are many routing algorithms have been proposed in recent years. To present the current state of development of UASN routing protocols, we review herein the UASN routing protocol designs reported in recent years. In this paper, all the routing protocols have been classified into different groups according to their characteristics and routing algorithms, such as the non-cross-layer design routing protocol, the traditional cross-layer design routing protocol, and the intelligent algorithm based routing protocol. This is also the first paper that introduces intelligent algorithm-based UASN routing protocols. In addition, in this paper, we investigate the development trends of UASN routing protocols, which can provide researchers with clear and direct insights for further research. PMID:27011193

  16. Class network routing

    DOEpatents

    Bhanot, Gyan; Blumrich, Matthias A.; Chen, Dong; Coteus, Paul W.; Gara, Alan G.; Giampapa, Mark E.; Heidelberger, Philip; Steinmacher-Burow, Burkhard D.; Takken, Todd E.; Vranas, Pavlos M.

    2009-09-08

    Class network routing is implemented in a network such as a computer network comprising a plurality of parallel compute processors at nodes thereof. Class network routing allows a compute processor to broadcast a message to a range (one or more) of other compute processors in the computer network, such as processors in a column or a row. Normally this type of operation requires a separate message to be sent to each processor. With class network routing pursuant to the invention, a single message is sufficient, which generally reduces the total number of messages in the network as well as the latency to do a broadcast. Class network routing is also applied to dense matrix inversion algorithms on distributed memory parallel supercomputers with hardware class function (multicast) capability. This is achieved by exploiting the fact that the communication patterns of dense matrix inversion can be served by hardware class functions, which results in faster execution times.

  17. Railroad Routing Model

    1995-01-05

    INTERLINE/PC is an interactive program designed to simulate the routing practices of the United States rail system. The rail industry is divided into a large number of independent competing companies. The INTERLINE data base represents these rail companies as 94 separate subnetworks. An additional two subnetworks represent navigable inland/intracoastal and deep draft marine routes. Interchange points between individual rail systems and waterway systems are also identified.

  18. Route Award Considerations

    NASA Technical Reports Server (NTRS)

    Rogers, W. D., Jr.

    1972-01-01

    The organization, responsibilities, and functions of the Civil Aeronautics Board are discussed. Several examples of decisions made by the Civil Aeronautics Board on the award of specific air routes to competing air lines are presented. The manner in which route proceedings are initiated and examined is explained. Recommendations are made concerning actions which can be taken to improve the services provided to the flying public.

  19. 21 CFR 73.1326 - Chromium hydroxide green.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... area of the eye. (d) Labeling requirements. The label of the color additive and of any mixtures... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1326 Chromium hydroxide green. (a) Identity. (1) The color additive chromium hydroxide green is principally hydrated chromic sesquioxide...

  20. 21 CFR 73.1326 - Chromium hydroxide green.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... area of the eye. (d) Labeling requirements. The label of the color additive and of any mixtures... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1326 Chromium hydroxide green. (a) Identity. (1) The color additive chromium hydroxide green is principally hydrated chromic sesquioxide...

  1. 21 CFR 73.1326 - Chromium hydroxide green.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... area of the eye. (d) Labeling requirements. The label of the color additive and of any mixtures... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1326 Chromium hydroxide green. (a) Identity. (1) The color additive chromium hydroxide green is principally hydrated chromic sesquioxide...

  2. 21 CFR 872.3250 - Calcium hydroxide cavity liner.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Calcium hydroxide cavity liner. 872.3250 Section 872.3250 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3250 Calcium hydroxide cavity liner....

  3. 21 CFR 872.3250 - Calcium hydroxide cavity liner.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Calcium hydroxide cavity liner. 872.3250 Section 872.3250 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3250 Calcium hydroxide cavity liner....

  4. 40 CFR 721.4467 - Quaternary ammonium hydroxide.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Quaternary ammonium hydroxide. 721... Substances § 721.4467 Quaternary ammonium hydroxide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a quaternary ammonium...

  5. 40 CFR 721.4467 - Quaternary ammonium hydroxide.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Quaternary ammonium hydroxide. 721... Substances § 721.4467 Quaternary ammonium hydroxide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a quaternary ammonium...

  6. A Survey on Clustering Routing Protocols in Wireless Sensor Networks

    PubMed Central

    Liu, Xuxun

    2012-01-01

    The past few years have witnessed increased interest in the potential use of wireless sensor networks (WSNs) in a wide range of applications and it has become a hot research area. Based on network structure, routing protocols in WSNs can be divided into two categories: flat routing and hierarchical or clustering routing. Owing to a variety of advantages, clustering is becoming an active branch of routing technology in WSNs. In this paper, we present a comprehensive and fine grained survey on clustering routing protocols proposed in the literature for WSNs. We outline the advantages and objectives of clustering for WSNs, and develop a novel taxonomy of WSN clustering routing methods based on complete and detailed clustering attributes. In particular, we systematically analyze a few prominent WSN clustering routing protocols and compare these different approaches according to our taxonomy and several significant metrics. Finally, we summarize and conclude the paper with some future directions. PMID:23112649

  7. Intercalation studies of zinc hydroxide chloride: Ammonia and amino acids

    SciTech Connect

    Arizaga, Gregorio Guadalupe Carbajal

    2012-01-15

    Zinc hydroxide chloride (ZHC) is a layered hydroxide salt with formula Zn{sub 5}(OH){sub 8}Cl{sub 2}{center_dot}2H{sub 2}O. It was tested as intercalation matrix for the first time and results were compared with intercalation products of the well-known zinc hydroxide nitrate and a Zn/Al layered double hydroxide. Ammonia was intercalated into ZHC, while no significant intercalation occurred in ZHN. Aspartic acid intercalation was only achieved by co-precipitation at pH=10 with ZHC and pH=8 with zinc hydroxide nitrate. Higher pH resistance in ZHC favored total deprotonation of both carboxylic groups of the Asp molecule. ZHC conferred more thermal protection against Asp combustion presenting exothermic peaks even at 452 Degree-Sign C while the exothermic event in ZHN was 366 Degree-Sign C and in the LDH at 276 Degree-Sign C. - Graphical abstract: The zinc hydroxide chloride (ZHC) with formula Zn{sub 5}(OH){sub 8}Cl{sub 2}{center_dot}2H{sub 2}O was tested as intercalation matrix. In comparison with the well-known zinc hydroxide nitrate (ZHN) and layered double hydroxides (LDH), ZHC was the best matrix for thermal protection of Asp combustion, presenting exothermic peaks even at 452 Degree-Sign C, while the highest exothermic event in ZHN was at 366 Degree-Sign C, and in the LDH it was at 276 Degree-Sign C. Highlights: Black-Right-Pointing-Pointer Zinc hydroxide chloride (ZHC) was tested as intercalation matrix for the first time. Black-Right-Pointing-Pointer ZHC has higher chemical and thermal stability than zinc hydroxide nitrate and LDH. Black-Right-Pointing-Pointer NH{sub 3} molecules can be intercalated into ZHC. Black-Right-Pointing-Pointer The amino group of amino acids limits the intercalation by ion-exchange.

  8. High pseudocapacitive cobalt carbonate hydroxide films derived from CoAl layered double hydroxides

    NASA Astrophysics Data System (ADS)

    Lu, Zhiyi; Zhu, Wei; Lei, Xiaodong; Williams, Gareth R.; O'Hare, Dermot; Chang, Zheng; Sun, Xiaoming; Duan, Xue

    2012-05-01

    A thin nanosheet of mesoporous cobalt carbonate hydroxide (MPCCH) has been fabricated from a CoAl-LDH nanosheet following removal of the Al cations by alkali etching. The basic etched electrode exhibits enhanced specific capacitance (1075 F g-1 at 5 mA cm-2) and higher rate capability and cycling stability (92% maintained after 2000 cycles).A thin nanosheet of mesoporous cobalt carbonate hydroxide (MPCCH) has been fabricated from a CoAl-LDH nanosheet following removal of the Al cations by alkali etching. The basic etched electrode exhibits enhanced specific capacitance (1075 F g-1 at 5 mA cm-2) and higher rate capability and cycling stability (92% maintained after 2000 cycles). Electronic supplementary information (ESI) available: Detailed experimental procedure, specific capacitance calculation, EDS and FTIR results, electrochemical results of CoAl-LDH and SEM image. See DOI: 10.1039/c2nr30617d

  9. Complex Microfiltration Behavior of Metal Hydroxide Slurries

    SciTech Connect

    Shimskey, Rick W.; Schonewill, Philip P.; Daniel, Richard C.; Peterson, Reid A.

    2011-02-28

    Crossflow filtration is to be a key process in the treatment and disposal of approximately 60,000 metric tons of high-level waste stored at the Hanford Site in Richland, Washington. Pacific Northwest National Laboratory is assessing filter performance against waste simulant materials that mimic the chemical and physical properties of Hanford tank waste. Prior simulant studies indicate that waste filtration performance may be limited by pore and cake fouling. To limit the shutdown of waste treatment operations, the pre-treatment facility plans to recover filter flux loses from cake formation and filter fouling by frequently backpulsing the filter elements. The objective of the current research is to develop an understanding of the roles of cake and pore fouling and potential flux recovery through backpulsing of the filters for Hanford waste filtration operations. Metal hydroxide wastes were tested to examine the role of particle-filter interaction on filter performance.

  10. Asymmetric Transport Mechanisms of Hydronium and Hydroxide Ions in Amorphous Solid Water: Hydroxide Goes Brownian while Hydronium Hops.

    PubMed

    Lee, Du Hyeong; Choi, Cheol Ho; Choi, Tae Hoon; Sung, Bong June; Kang, Heon

    2014-08-01

    The diffusion of hydronium (H3O(+)) and hydroxide (OH(-)) ions is one of the most intriguing topics in aqueous chemistry. It is considered that these ions in aqueous solutions move via sequential proton transfer events, known as the Grotthuss mechanisms. Here, we present an experimental study of the diffusion and H/D exchange of hydronium and hydroxide ions in amorphous solid water (ASW) at 140-180 K by using low-energy sputtering (LES) and temperature-programmed desorption (TPD) measurements. The study shows that the two species transport in ASW via fundamentally different molecular mechanisms. Whereas hydronium ions migrate via efficient proton transfer, hydroxide ions move via Brownian molecular diffusion without proton transfer. The molecular hydroxide diffusion in ASW is in stark contrast to the current view of the hydroxide diffusion mechanism in aqueous solution, which involves proton transfer.

  11. Rare earth and zinc layered hydroxide salts intercalated with the 2-aminobenzoate anion as organic luminescent sensitizer

    SciTech Connect

    Cursino, Ana Cristina Trindade; Rives, Vicente; Trujillano, Raquel

    2015-10-15

    Rare earth (RE = Eu, Y and Tb) and zinc layered hydroxide salts intercalated with nitrate anions were synthesized, followed by exchange with 2-aminobenzoate. The UV absorption ability was improved after intercalation/grafting in relation to that shown by the parent material. - Highlights: • Rare earth (RE = Eu, Y and Tb) and zinc layered hydroxide were synthesized. • Intercalated nitrate anions were exchanged by 2-aminobenzoate. • In all the 2-aminobenzoate containing compounds, the grafting reaction was detected. • The UV absorption ability was improved after the exchange reactions. • Rare earth hydroxide salts are potential matrixes to produce luminescent materials. - Abstract: Rare earth (RE = Eu, Y and Tb) and zinc layered hydroxide salts intercalated with nitrate anions were synthesized, followed by exchange with 2-aminobenzoate. The obtained compounds were characterized by powder X-ray diffraction (PXRD), Fourier transform infrared (FTIR) and ultraviolet visible (UV–vis) spectroscopies, fluorescence measurements and thermal analysis (TGA/DTA). The results from FTIR spectroscopy suggest a direct coordination of 2-aminobenzoate to the metal cations of the inorganic layered structure. The organic derivative products from the intercalation reactions absorb a broader range of UV-light in relation to that shown by the parent material; the photoluminescence measurements present a strong violet, blue and green luminescence under UV-light excitation for layered compounds with, Zn, Y and Tb, respectively. Rare earth hydroxide salts (RE-LHS) are potential alternative matrices for the immobilization of organic species to produce luminescent materials.

  12. The importance of second shell effects in the simulation of hydrated Sr²⁺ hydroxide complexes.

    PubMed

    Makkos, Eszter; Kerridge, Andrew; Kaltsoyannis, Nikolas

    2015-07-01

    Density functional theory at the meta-GGA level is employed to study the microsolvation of Sr(2+) hydroxides, in order to establish likely candidate species for the interaction of nuclear fission-generated strontium with corroded Magnox fuel cladding in high pH spent nuclear fuel storage ponds. A combination of the COSMO continuum solvation model and one or two shells of explicit water molecules is employed. Inclusion of only a single explicit solvation shell is unsatisfactory; open regions are present in the strontium coordination shell which would not exist in real aqueous complexes, and many optimised structures possess unavoidable energetic instabilities. Incorporation of a second shell of explicit waters, however, yields energetically minimal structures without open regions in the first strontium coordination shell. The most stable systems with one, two or three hydroxide ions are all 6-coordinated with a distorted trigonal antiprismatic geometry, whereas systems with four OH(-) ions have a most stable coordination number of five. Transformation, via a proton transfer mechanism, from one coordination mode to another (e.g. from a system with two hydroxides bound directly to the strontium to one in which a hydroxide ion migrates into the second coordination shell) is found to be energetically facile. It is concluded that the most likely strontium-hydroxide complexes to be found in high pH aqueous solutions are mono- and dihydroxides, and that these coexist. PMID:26041401

  13. A model of ant route navigation driven by scene familiarity.

    PubMed

    Baddeley, Bart; Graham, Paul; Husbands, Philip; Philippides, Andrew

    2012-01-01

    In this paper we propose a model of visually guided route navigation in ants that captures the known properties of real behaviour whilst retaining mechanistic simplicity and thus biological plausibility. For an ant, the coupling of movement and viewing direction means that a familiar view specifies a familiar direction of movement. Since the views experienced along a habitual route will be more familiar, route navigation can be re-cast as a search for familiar views. This search can be performed with a simple scanning routine, a behaviour that ants have been observed to perform. We test this proposed route navigation strategy in simulation, by learning a series of routes through visually cluttered environments consisting of objects that are only distinguishable as silhouettes against the sky. In the first instance we determine view familiarity by exhaustive comparison with the set of views experienced during training. In further experiments we train an artificial neural network to perform familiarity discrimination using the training views. Our results indicate that, not only is the approach successful, but also that the routes that are learnt show many of the characteristics of the routes of desert ants. As such, we believe the model represents the only detailed and complete model of insect route guidance to date. What is more, the model provides a general demonstration that visually guided routes can be produced with parsimonious mechanisms that do not specify when or what to learn, nor separate routes into sequences of waypoints. PMID:22241975

  14. A model of ant route navigation driven by scene familiarity.

    PubMed

    Baddeley, Bart; Graham, Paul; Husbands, Philip; Philippides, Andrew

    2012-01-01

    In this paper we propose a model of visually guided route navigation in ants that captures the known properties of real behaviour whilst retaining mechanistic simplicity and thus biological plausibility. For an ant, the coupling of movement and viewing direction means that a familiar view specifies a familiar direction of movement. Since the views experienced along a habitual route will be more familiar, route navigation can be re-cast as a search for familiar views. This search can be performed with a simple scanning routine, a behaviour that ants have been observed to perform. We test this proposed route navigation strategy in simulation, by learning a series of routes through visually cluttered environments consisting of objects that are only distinguishable as silhouettes against the sky. In the first instance we determine view familiarity by exhaustive comparison with the set of views experienced during training. In further experiments we train an artificial neural network to perform familiarity discrimination using the training views. Our results indicate that, not only is the approach successful, but also that the routes that are learnt show many of the characteristics of the routes of desert ants. As such, we believe the model represents the only detailed and complete model of insect route guidance to date. What is more, the model provides a general demonstration that visually guided routes can be produced with parsimonious mechanisms that do not specify when or what to learn, nor separate routes into sequences of waypoints.

  15. Removal of boron species by layered double hydroxides: a review.

    PubMed

    Theiss, Frederick L; Ayoko, Godwin A; Frost, Ray L

    2013-07-15

    Boron, which is an essential element for plants, is toxic to humans and animals at high concentrations. Layered double hydroxides (LDHs) and thermally activated LDHs have shown good uptake of a range of boron species in laboratory scale experiments when compared to current available methods, which are for the most part ineffective or prohibitively expensive. LDHs were able to remove anions from water by anion exchange, the reformation (or memory) effect and direct precipitation. The main mechanism of boron uptake appeared to be anion exchange, which was confirmed by powder X-ray diffraction (XRD) measurements. Solution pH appeared to have little effect on boron sorption while thermal activation did not always significantly improve boron uptake. In addition, perpetration of numerous LDHs with varying boron anions in the interlayer region by direct co-precipitation and anion exchange have been reported by a number of groups. The composition and orientation of the interlayer boron ions could be identified with reasonable certainty by applying a number of characterisation techniques including: powder XRD, nuclear magnetic resonance spectroscopy (NMR), X-ray photoelectron spectroscopy (XPS) and infrared (IR) spectroscopy. There is still considerable scope for future research on the application of LDHs for the removal of boron contaminants.

  16. Removal of boron species by layered double hydroxides: a review.

    PubMed

    Theiss, Frederick L; Ayoko, Godwin A; Frost, Ray L

    2013-07-15

    Boron, which is an essential element for plants, is toxic to humans and animals at high concentrations. Layered double hydroxides (LDHs) and thermally activated LDHs have shown good uptake of a range of boron species in laboratory scale experiments when compared to current available methods, which are for the most part ineffective or prohibitively expensive. LDHs were able to remove anions from water by anion exchange, the reformation (or memory) effect and direct precipitation. The main mechanism of boron uptake appeared to be anion exchange, which was confirmed by powder X-ray diffraction (XRD) measurements. Solution pH appeared to have little effect on boron sorption while thermal activation did not always significantly improve boron uptake. In addition, perpetration of numerous LDHs with varying boron anions in the interlayer region by direct co-precipitation and anion exchange have been reported by a number of groups. The composition and orientation of the interlayer boron ions could be identified with reasonable certainty by applying a number of characterisation techniques including: powder XRD, nuclear magnetic resonance spectroscopy (NMR), X-ray photoelectron spectroscopy (XPS) and infrared (IR) spectroscopy. There is still considerable scope for future research on the application of LDHs for the removal of boron contaminants. PMID:23635479

  17. Setting process of lime-based conservation mortars with barium hydroxide

    SciTech Connect

    Karatasios, Ioannis . E-mail: ikarat@ims.demokritos.gr; Kilikoglou, Vassilis; Colston, Belinda; Theoulakis, Panagiotis; Watt, David

    2007-06-15

    This paper presents the effect of barium hydroxide on the setting mechanism of lime-based conservation mortars, when used as an additive material. The study focuses on the monitoring of the setting process and the identification of the mineral phases formed, which are essential for furthering the study of the durability of barium mixtures against chemical degradation. X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and thermal analysis (DTA-TG) were used to monitor the setting processes of these mixtures and identify new phases formed. The results suggest that barium hydroxide is evenly distributed within the lime and produces a homogeneous binding material, consisting of calcite (CaCO{sub 3}), witherite (BaCO{sub 3}) and barium-calcium carbonate [BaCa(CO{sub 3}){sub 2}]. Finally, it was found that barium carbonate can be directly bonded to calcitic aggregates and therefore increases its chemical compatibility with the binding material.

  18. Autopsy results of a case of ingestion of sodium hydroxide solution.

    PubMed

    Emoto, Yuko; Yoshizawa, Katsuhiko; Shikata, Nobuaki; Tsubura, Airo; Nagasaki, Yasushi

    2016-01-01

    Sodium hydroxide is a strongly corrosive alkali. We describe herein a case of suicide by ingestion of sodium hydroxide. A man in his 80s was found dead with a mug and a bottle of caustic soda. Macroscopically, liquefaction and/or disappearance of esophagus, trachea and lung tissue and a grayish discoloration of the mucosa of the stomach were seen along with blackish brown coloration of the skin, mouth, and oral cavity. The contents of the gastrointestinal tract showed a pH level of 7-8 on pH indicator strips. Histopathologically, liquefactive necrosis of remnant lung tissue and the stomach were seen. As biological reactions such as vasodilatation and inflammation were not detected in these organs, only a short number of hours must have passed between ingestion and death. This human case provides valuable information concerning the direct irritation induced by systemic exposure to corrosive substances. PMID:26989301

  19. Autopsy results of a case of ingestion of sodium hydroxide solution

    PubMed Central

    Emoto, Yuko; Yoshizawa, Katsuhiko; Shikata, Nobuaki; Tsubura, Airo; Nagasaki, Yasushi

    2015-01-01

    Sodium hydroxide is a strongly corrosive alkali. We describe herein a case of suicide by ingestion of sodium hydroxide. A man in his 80s was found dead with a mug and a bottle of caustic soda. Macroscopically, liquefaction and/or disappearance of esophagus, trachea and lung tissue and a grayish discoloration of the mucosa of the stomach were seen along with blackish brown coloration of the skin, mouth, and oral cavity. The contents of the gastrointestinal tract showed a pH level of 7–8 on pH indicator strips. Histopathologically, liquefactive necrosis of remnant lung tissue and the stomach were seen. As biological reactions such as vasodilatation and inflammation were not detected in these organs, only a short number of hours must have passed between ingestion and death. This human case provides valuable information concerning the direct irritation induced by systemic exposure to corrosive substances. PMID:26989301

  20. Autopsy results of a case of ingestion of sodium hydroxide solution.

    PubMed

    Emoto, Yuko; Yoshizawa, Katsuhiko; Shikata, Nobuaki; Tsubura, Airo; Nagasaki, Yasushi

    2016-01-01

    Sodium hydroxide is a strongly corrosive alkali. We describe herein a case of suicide by ingestion of sodium hydroxide. A man in his 80s was found dead with a mug and a bottle of caustic soda. Macroscopically, liquefaction and/or disappearance of esophagus, trachea and lung tissue and a grayish discoloration of the mucosa of the stomach were seen along with blackish brown coloration of the skin, mouth, and oral cavity. The contents of the gastrointestinal tract showed a pH level of 7-8 on pH indicator strips. Histopathologically, liquefactive necrosis of remnant lung tissue and the stomach were seen. As biological reactions such as vasodilatation and inflammation were not detected in these organs, only a short number of hours must have passed between ingestion and death. This human case provides valuable information concerning the direct irritation induced by systemic exposure to corrosive substances.

  1. Morphology-controlled nonaqueous synthesis of anisotropic lanthanum hydroxide nanoparticles

    SciTech Connect

    Djerdj, Igor; Garnweitner, Georg; Sheng Su, Dang; Niederberger, Markus

    2007-07-15

    The preparation of lanthanum hydroxide and manganese oxide nanoparticles is presented, based on a nonaqueous sol-gel process involving the reaction of La(OiPr){sub 3} and KMnO{sub 4} with organic solvents such as benzyl alcohol, 2-butanone and a 1:1 vol. mixture thereof. The lanthanum manganese oxide system is highly complex and surprising results with respect to product composition and morphology were obtained. In dependence of the reaction parameters, the La(OH){sub 3} nanoparticles undergo a shape transformation from short nanorods with an average aspect ratio of 2.1 to micron-sized nanofibers (average aspect ratio is more than 59.5). Although not directly involved, KMnO{sub 4} plays a crucial role in determining the particle morphology of La(OH){sub 3}. The reason lies in the fact that KMnO{sub 4} is able to oxidize the benzyl alcohol to benzoic acid, which presumably induces the anisotropic particle growth in [0 0 1] direction upon preferential coordination to the {+-}(1 0 0), {+-}(0 1 0) and {+-}(-110) crystal facets. By adjusting the molar La(OiPr){sub 3}-to-KMnO{sub 4} ratio as well as by using the appropriate solvent mixture it is possible to tailor the morphology, phase purity and microstructure of the La(OH){sub 3} nanoparticles. Postsynthetic thermal treatment of the sample containing La(OH){sub 3} nanofibers and {beta}-MnOOH nanoparticles at the temperature of 800 deg. C for 8 h yielded polyhedral LaMnO{sub 3} and worm-like La{sub 2}O{sub 3} nanoparticles as final products. - Graphical abstract: Lanthanum hydroxide nanoparticles are synthesized based on a nonaqueous sol-gel process involving the reaction of La(OiPr){sub 3} and KMnO{sub 4} with organic solvents such as benzyl alcohol, 2-butanone and a 1:1 vol. mixture thereof. In dependence of the reaction parameters, the La(OH){sub 3} nanoparticles undergo a shape transformation from short nanorods to micron-sized nanofibers.

  2. Juvenile nasopharyngeal angiofibroma: the routes of invasion.

    PubMed

    Sennes, Luiz U; Butugan, Ossamu; Sanchez, Tanit G; Bento, Ricardo F; Tsuji, Domingos H

    2003-12-01

    The juvenile nasopharyngeal angiofibroma has a characteristic growth in all directions from its origin. However, the extensions of the tumor seem to be independent, each one with distinct behavior. The aim of this study is to analyze the preferential direction and routes of JNA growth, as well as its correlation with the patient's age. We analyzed 33 patients without any previous treatment, attempting to the extension and routes of tumor's growth (CT scan), and its correlation with the patient's age. The sphenopalatine foramen region was affected in all cases. From this point, a growth towards several routes with a different rhythm was noted, determining variable configurations to the tumor. The lateral and superior growths were the most frequent. The expansion into the pterygopalatine fossa was very frequent and could involve important anatomical structures, determining higher morbidity. Three sites were invaded through more than one route: pterygoid fossa, middle cranial fossa and maxillary sinus. There was no significant correlation between invasion route and patient's age. However, considering the age, there was a concomitance between tumor development and facial growth by "displacement". We discuss this condition, suggesting an explanation to the tumor invasion and expansion inside the pterygopalatine fossa.

  3. [Effects of the treatment of coffee pulp, fresh or ensilaged, with calcium hydroxide, on its nutritive value].

    PubMed

    Gómez-Brenes, R; Bendaña, G; González, J M; Jarquín, R; Braham, J E; Bressani, R

    1988-03-01

    This study was carried out to determine the effects of the addition of calcium hydroxide on the chemical composition and nutritive value of fresh or ensilaged coffee pulp. Fresh or ensilaged pulp were mixed with 1, 2 and 3% of calcium hydroxide. The process was carried out during 0 and 16 hr, after which time the treated pulp was sun-dried for 36 hr until moisture content reached 12%. These samples were then analyzed for their proximate chemical composition and for some minerals (Ca, P, Na, K), as well as for caffeine, tannins and chlorogenic and caffeic acids content. Diets were then prepared from these materials, containing 15% protein and 15 or 30% fresh or ensilaged coffee pulp, and offered to weanling rats during six weeks. Information required on weight gain, food conversion, apparent digestibility and toxicity of the diets was recorded. Results of the chemical analysis revealed that the main changes found in both types of pulp as a result of the calcium hydroxide treatment were the following: a decrease in ether extract (from 4.0 to 2.5 g/100 g), crude fiber (from 18.3 to 11.9 g/100 g) and protein content (from 12.3 to 8.6 g/100 g) in an inverse relation to the amount of calcium hydroxide used. The amount of ash increased, fluctuated between 5.5 and 15.4%, depending on the amount of calcium hydroxide used. The latter affected the Ca:P ratio in the diets, where an average ratio of 7.2:1 was found in the control pulp (0% calcium hydroxide) and 59.0:1 in those treated with the highest amount of calcium hydroxide (3%). Regarding the caffeine, tannins and chlorogenic and caffeic acids contents, calcium hydroxide was effective in decreasing only tannins, more so in the fresh than in the ensilaged pulp; the decrease was in direct proportion to the amount of calcium hydroxide added and to the length of the Ca(OH)2 treatment. The results of the biological assays showed that the addition of Ca(OH)2 in either of the two time periods used and at either of the

  4. Complications of sodium hydroxide chemical matrixectomy: nail dystrophy, allodynia, hyperalgesia.

    PubMed

    Bostancı, Seher; Koçyiğit, Pelin; Güngör, Hilayda Karakök; Parlak, Nehir

    2014-11-01

    Ingrown toenails are seen most commonly in young adults, and they can seriously affect daily life. Partial nail avulsion with chemical matrixectomy, generally by using either sodium hydroxide or phenol, is one of the most effective treatment methods. Known complications of phenol matrixectomy are unpredictable tissue damage, prolonged postoperative drainage, increased secondary infection rates, periostitis, and poor cosmetic results. To our knowledge, there have been no reports about the complications related to sodium hydroxide matrixectomy. Herein, we describe three patients who developed nail dystrophy, allodynia, and hyperalgesia after sodium hydroxide matrixectomy.

  5. Hydrothermal preparation of fractal dendrites: Cerium carbonate hydroxide and cerium oxide

    SciTech Connect

    Wu Mingzai; Zhang Qihua; Liu Yanmei; Fang Qingqing; Liu Xiansong

    2009-06-03

    The surfactant-assisted hydrothermal route was used to prepare fractal dendrite cerium carbonate hydroxide (CeOHCO{sub 3}) microstructures. After annealing at 600 deg. C for 4 h, the products were transformed to CeO{sub 2}. The crystal structures of the two compounds were determined by X-ray diffraction (XRD). The morphologies and microstructures were characterized by field emission scanning electron microscopy (FESEM) and high-resolution transmission electron microscopy (HRTEM). Room temperature photoluminescence (PL) showed that a strong ultraviolet emission at 336 nm was observed for CeOHCO{sub 3}, and that centered at 415 nm for CeO{sub 2} microstructures. Both of these emission peaks are different from those reported for CeOHCO{sub 3} and CeO{sub 2} with other shapes. In addition, the possible growth mechanism of dendrite CeOHCO{sub 3} microstructures and the role of surfactant polyvinyl pyrrolidone (PVP) were also investigated in this paper.

  6. Stabilization of Co{sup 2+} in layered double hydroxides (LDHs) by microwave-assisted ageing

    SciTech Connect

    Herrero, M.; Benito, P.; Labajos, F.M.; Rives, V.

    2007-03-15

    Co-containing layered double hydroxides at different pH have been prepared, and aged following different routes. The solids prepared have been characterized by element chemical analysis, powder X-ray diffraction, thermogravimetric and differential thermal analyses (both in nitrogen and in oxygen), FT-IR and Vis-UV spectroscopies, temperature-programmed reduction and surface area assessment by nitrogen adsorption at -196 deg. C. The best conditions found to preserve the cobalt species in the divalent oxidation state are preparing the samples at controlled pH, and then submit them to ageing under microwave irradiation. - Graphical abstract: The use of microwave-hydrothermal treatment, controlling both temperature and ageing time, permits to synthesize well-crystallized nanomaterials with controlled surface properties. An enhancement in the crystallinity degree and an increase in the particle size are observed when the irradiation time is prolonged.

  7. Would you follow your own route description? Cognitive strategies in urban route planning.

    PubMed

    Hölscher, Christoph; Tenbrink, Thora; Wiener, Jan M

    2011-11-01

    This paper disentangles cognitive and communicative factors influencing planning strategies in the everyday task of choosing a route to a familiar location. Describing the way for a stranger in town calls for fundamentally different cognitive processes and strategies than actually walking to a destination. In a series of experiments, this paper addresses route choices, planning processes, and description strategies in a familiar urban environment when asked to walk to a goal location, to describe a route for oneself, or to describe a route for an addressee. Results show systematic differences in the chosen routes with respect to efficiency, number of turns and streets, and street size. The analysis of verbal data provides consistent further insights concerning the nature of the underlying cognitive processes. Actual route navigation is predominantly direction-based and characterized by incremental perception-based optimization processes. In contrast, in-advance route descriptions draw on memory resources to a higher degree and accordingly rely more on salient graph-based structures, and they are affected by concerns of communicability. The results are consistent with the assumption that strategy choice follows a principle of cognitive economy that is highly adaptive to the degree of perceptual information available for the task.

  8. Hydrologic Flood Routing.

    ERIC Educational Resources Information Center

    Heggen, Richard J.

    1982-01-01

    Discusses a short classroom-based BASIC program which routes stream flow through a system of channels and reservoirs. The program is suitable for analyses of open channel conveyance systems, flood detention reservoirs, and combinations of the two. (Author/JN)

  9. Submarine cable route survey

    SciTech Connect

    Herrouin, G.; Scuiller, T.

    1995-12-31

    The growth of telecommunication market is very significant. From the beginning of the nineties, more and more the use of optical fiber submarine cables is privileged to that of satellites. These submarine telecommunication highways require accurate surveys in order to select the optimum route and determine the cable characteristics. Advanced technology tools used for these surveys are presented along with their implementation.

  10. Evidence for Multiple Routes in Learning to Read

    ERIC Educational Resources Information Center

    Grainger, Jonathan; Lete, Bernard; Bertand, Daisy; Dufau, Stephane; Ziegler, Johannes C.

    2012-01-01

    We describe a multiple-route model of reading development in which coarse-grained orthographic processing plays a key role in optimizing access to semantics via whole-word orthographic representations. This forms part of the direct orthographic route that gradually replaces phonological recoding during the initial phases of reading acquisition.…

  11. Homogeneous Precipitation of Nickel Hydroxide Powders

    SciTech Connect

    Bora Mavis

    2003-12-12

    Precipitation and characterization of nickel hydroxide powders were investigated. A comprehensive precipitation model incorporating the metal ion hydrolysis, complexation and precipitation reactions was developed for the production of the powders with urea precipitation method. Model predictions on Ni{sup 2+} precipitation rate were confirmed with precipitation experiments carried out at 90 C. Experimental data and model predictions were in remarkable agreement. Uncertainty in the solubility product data of nickel hydroxides was found to be the large contributor to the error. There were demonstrable compositional variations across the particle cross-sections and the growth mechanism was determined to be the aggregation of primary crystallites. This implied that there is a change in the intercalate chemistry of the primary crystallites with digestion time. Predicted changes in the concentrations of simple and complex ions in the solution support the proposed mechanism. The comprehensive set of hydrolysis reactions used in the model described above allows the investigation of other systems provided that accurate reaction constants are available. the fact that transition metal ions like Ni{sup 2+} form strong complexes with ammonia presents a challenge in the full recovery of the Ni{sup 2+}. On the other hand, presence of Al{sup 3+} facilitates the complete precipitation of Ni{sup 2+} in about 3 hours of digestion. A challenge in their predictive modeling studies had been the fact that simultaneous incorporation of more than one metal ion necessitates a different approach than just using the equilibrium constants of hydrolysis, complexation and precipitation reactions. Another limitation of using equilibrium constants is that the nucleation stage of digestion, which is controlled mainly by kinetics, is not fully justified. A new program released by IBM Almaden Research Center (Chemical Kinetics Simulator{trademark}, Version 1.01) lets the user change the order of

  12. Bio-template route for facile fabrication of Cd(OH){sub 2}@yeast hybrid microspheres and their subsequent conversion to mesoporous CdO hollow microspheres

    SciTech Connect

    Bai, Bo; Guan, Weisheng; Li, Ziyan; Li Puma, Gianluca

    2011-01-15

    Cadmium oxide (CdO) microspheres with a porous hollow microstructure were prepared by a facile yeast mediated bio-template route. The yeast provides a solid scaffold for the deposition of cadmium hydroxide (Cd(OH){sub 2}) from cadmium acetate and sodium hydroxide solutions to form the hybrid Cd(OH){sub 2}@yeast precursor. Thermal conversions of this at above 500 {sup o}C in air have produced hollow CdO microspheres. The products were characterized by scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FT-IR), thermal gravimetric and differential thermal analysis (TGA-DTA), and Brunauer-Emmett-Teller (BET) surface analysis respectively. The obtained CdO microspheres have uniform size (length = 2.6 {+-} 0.4 {mu}m; width = 2.0 {+-} 0.2 {mu}m) and a well defined, continuous, mesoporous hollow microstructure. The shell is about 250-280 nm in thickness. The mechanism of formation of Cd(OH){sub 2}@yeast precursor and its conversion to CdO hollow microspheres is discussed. In comparison with traditional template-directed method, the present strategy represents a general, economical and environmentally benign route for the formation of metal oxide hollow microspheres. These materials have potential applications in different fields such as encapsulation, drug delivery, efficient catalysis, battery materials and photonic crystals. The method presented can be extended to the synthesis of other inorganic hollow microstructures of different sizes and shapes by pre-selecting suitable bio-templates.

  13. Aerosol immunisation for TB: matching route of vaccination to route of infection.

    PubMed

    Manjaly Thomas, Zita-Rose; McShane, Helen

    2015-03-01

    TB remains a very significant global health burden. There is an urgent need for better tools for TB control, which include an effective vaccine. Bacillus Calmette-Guérin (BCG), the currently licensed vaccine, confers highly variable protection against pulmonary TB, the main source of TB transmission. Replacing BCG completely or boosting BCG with another vaccine are the two current strategies for TB vaccine development. Delivering a vaccine by aerosol represents a way to match the route of vaccination to the route of infection. This route of immunisation offers not only the scientific advantage of delivering the vaccine directly to the respiratory mucosa, but also practical and logistical advantages. This review summarises the state of current TB vaccine candidates in the pipeline, reviews current progress in aerosol administration of vaccines in general and evaluates the potential for TB vaccine candidates to be administered by the aerosol route.

  14. Hydroxide-Assisted Bonding of Ultra-Low-Expansion Glass

    NASA Technical Reports Server (NTRS)

    Abramovici, Alexander; White, Victor

    2008-01-01

    A process for hydroxide-assisted bonding has been developed as a means of joining optical components made of ultra-low-expansion (ULE) glass, while maintaining sufficiently precise alignment between. The process is intended mainly for use in applications in which (1) bonding of glass optical components by use of epoxy does not enable attainment of the required accuracy and dimensional stability and (2) conventional optical contacting (which affords the required accuracy and stability) does not afford adequate bond strength. The basic concept of hydroxide-assisted bonding is not new. The development of the present process was prompted by two considerations: (1) The expertise in hydroxide-assisted bonding has resided in very few places and the experts have not been willing to reveal the details of their processes and (2) data on the reliability and strength attainable by hydroxide-assisted bonding have been scarce.

  15. 68. INTERIOR VIEW LOOKING OF THE CAUSTIC SODA (SODIUM HYDROXIDE) ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    68. INTERIOR VIEW LOOKING OF THE CAUSTIC SODA (SODIUM HYDROXIDE) BUILDING, LOOKING AT CAUSTIC SODA MEASURING TANKS. (DATE UNKNOWN). - United States Nitrate Plant No. 2, Reservation Road, Muscle Shoals, Muscle Shoals, Colbert County, AL

  16. 21 CFR 73.2326 - Chromium hydroxide green.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2326 Chromium hydroxide green. (a) Identity and... in coloring externally applied cosmetics, including those intended for use in the area of the eye,...

  17. 21 CFR 73.2326 - Chromium hydroxide green.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2326 Chromium hydroxide green. (a) Identity and... in coloring externally applied cosmetics, including those intended for use in the area of the eye,...

  18. 21 CFR 73.2326 - Chromium hydroxide green.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2326 Chromium hydroxide green. (a) Identity and... in coloring externally applied cosmetics, including those intended for use in the area of the eye,...

  19. Conversion coatings prepared or treated with calcium hydroxide solutions

    NASA Technical Reports Server (NTRS)

    Minevski, Zoran (Inventor); Clarke, Eric (Inventor); Maxey, Jason (Inventor); Nelson, Carl (Inventor); Eylem, Cahit (Inventor)

    2002-01-01

    A conversion coating process that forms a stable and corrosion-resistant oxide layer on metal or metal oxide substrates or layers. Particularly, the conversion coating process involves contacting the metal or metal oxide substrate or layer with the aqueous calcium hydroxide solutions in order to convert the surface of the substrate to a stable metal oxide layer or coating. According to the present invention, the calcium hydroxide solution is prepared by removing carbon dioxide from water or an aqueous solution before introducing the calcium hydroxide. In this manner, formation of calcium carbonate particles is avoided and the porosity of the conversion coating produced by the calcium hydroxide solution is reduced to below about 1%.

  20. Quantification of Iron Oxides and Hydroxides in Desert Aeolian Particles

    NASA Astrophysics Data System (ADS)

    Lafon, S.; Rajot, J.; Alfaro, S.; Gaudichet, A.

    2002-12-01

    Long range transport of desert dust over oceans constitute a source of iron for the surface water. Assessing the iron cycle and its biogeochemical implications in oceanic areas requires determination and quantification of the iron status in aeolian particles. Indeed, in such aerosols, the iron is either trapped in the silicate structure or present under the form of oxides and hydroxides (free iron). We propose a method to apportion iron between free and entrapped forms in mineral aerosols. It consists in the adaptation of a well known method used for soil characterization to the treatment of aerosol samples, which represent less than 1 mg of material collected by air filtration on polycarbonate filters. The iron oxides and hydroxides are extracted selectively using the combined action of reductive and complexant agents in a buffered solution. The iron content is measured before and after this chemical extraction using X ray fluorescence spectrometry. We attempt to give some values for three main desert source areas using aerosol samples collected near Niamey (Niger) either during Harmattan events or during local erosion events, and samples collected downwind of the Gobi desert in China. Results emphasize firstly that iron trapped in the structure of silicate minerals represents an important part of total iron content. This suggests that, regarding dissolution processes in sea water, total elemental iron content of aeolian dust can not be used directly to calculate the flux of iron available. Secondly, our results show that the free iron content vary according to the origin of dusts. Niger samples have contents in free iron of 4.4 % (SD = 0.8) for local erosion and 2.8 % (SD = 1.0) for Harmattan. Chinese samples contain 3.7 % (SD = 0.5) of free iron. These differences could be linked to the parent soil mineralogical composition that varies with geographical location, but for some of our samples it also could be linked to a size fractionation process occurring first

  1. Ferric Phosphate Hydroxide Microstructures Affect Their Magnetic Properties.

    PubMed

    Zhao, Junhong; Zhang, Youjuan; Run, Zhen; Li, Pengwei; Guo, Qifei; Pang, Huan

    2015-06-01

    Uniformly sized and shape-controlled nanoparticles are important due to their applications in catalysis, electrochemistry, ion exchange, molecular adsorption, and electronics. Several ferric phosphate hydroxide (Fe4(OH)3(PO4)3) microstructures were successfully prepared under hydrothermal conditions. Using controlled variations in the reaction conditions, such as reaction time, temperature, and amount of hexadecyltrimethylammonium bromide (CTAB), the crystals can be grown as almost perfect hyperbranched microcrystals at 180 °C (without CTAB) or relatively monodisperse particles at 220 °C (with CTAB). The large hyperbranched structure of Fe4(OH)3(PO4)3 with a size of ∼19 μm forms with the "fractal growth rule" and shows many branches. More importantly, the magnetic properties of these materials are directly correlated to their size and micro/nanostructure morphology. Interestingly, the blocking temperature (T B) shows a dependence on size and shape, and a smaller size resulted in a lower T B. These crystals are good examples that prove that physical and chemical properties of nano/microstructured materials are related to their structures, and the precise control of the morphology of such functional materials could allow for the control of their performance.

  2. Toxicity of Calcium Hydroxide Nanoparticles on Murine Fibroblast Cell Line

    PubMed Central

    Dianat, Omid; Azadnia, Sina; Mozayeni, Mohammad Ali

    2015-01-01

    Introduction: One of the major contributing factors, which may cause failure of endodontic treatment, is the presence of residual microorganisms in the root canal system. For years, most dentists have been using calcium hydroxide (CH) as the intracanal medicament between treatment sessions to eliminate remnant microorganisms. Reducing the size of CH particles into nanoparticles enhances the penetration of this medicament into dentinal tubules and increases their antimicrobial efficacy. This in vitro study aimed to compare the cytotoxicity of CH nanoparticles and conventional CH on fibroblast cell line using the Mosmann’s Tetrazolium Toxicity (MTT) assay. Methods and Materials: This study was conducted on L929 murine fibroblast cell line by cell culture and evaluation of the direct effect of materials on the cultured cells. Materials were evaluated in two groups of 10 samples each at 24, 48 and 72 h. At each time point, 10 samples along with 5 positive and 5 negative controls were evaluated. The samples were transferred into tubes and exposed to fibroblast cells. The viability of cells was then evaluated. The Two-way ANOVA was used for statistical analysis and the level of significance was set at 0.05. Results: Cytotoxicity of both materials decreased over time and for conventional CH was lower than that of nanoparticles. However, this difference was not statistically significant (P>0.05). Conclusion: The cytotoxicity of CH nanoparticles was similar to that of conventional CH. PMID:25598810

  3. Dielectric, magnetic, and phonon properties of nickel hydroxide

    NASA Astrophysics Data System (ADS)

    Hermet, P.; Gourrier, L.; Bantignies, J.-L.; Ravot, D.; Michel, T.; Deabate, S.; Boulet, P.; Henn, F.

    2011-12-01

    We carried out a complete study (magnetic, electronic, dielectric, dynamic, and elastic properties) of the nickel hydroxide [Ni(OH)2] from first-principles calculations based on density functional theory. No theoretical investigations of these physical properties have been previously reported in literature. Our work supports that Ni(OH)2 is an A-type antiferromagnetic material. In addition, it is negative uniaxial and semiconducting with a direct band gap at the Γ point around 3 eV. By contrast to its electronic dielectric tensor, its static tensor is strongly anisotropic in the plane orthogonal to its optical axis. This anisotropy is mainly governed by a highly polar phonon centered around 510 cm-1 and assigned as a rotational Eu mode. Both Raman and infrared spectra have been computed to clarify the longstanding debate on the assignment of the Ni(OH)2 phonon modes reported in literature. All these theoretical results are fruitfully compared to the experimental ones obtained on large Ni(OH)2 “pseudosingle” crystals when available.

  4. Weather routing in long-distance Mediterranean routes

    NASA Astrophysics Data System (ADS)

    Delitala, A. M. S.; Gallino, S.; Villa, L.; Lagouvardos, K.; Drago, A.

    2010-10-01

    The selection of ship routes based on modern weather forecasting is a mean of computing optimum shipping routes thereby increasing safety and comfort at sea, cutting down on transit time, and reducing fuel consumption. Further empirical research in the effectiveness of modern weather routing applications is required especially in applications concerning shorter routes in enclosed seas of limited geographical extent such as the Mediterranean Sea. The present study used two climatological simulations to test this state-of-the-art approach to ship routing. Simulations represented two theoretical routes: (1) a route between Italy and Greece and (2) a route between Cyprus and Italy. Both routes were analyzed across varying simulated climatic conditions and the results were compared with those of control routes. Furthermore, results were analyzed in terms of passenger and crew comfort, bunker consumption by ships, and time of crossing. The first simulation showed that weather routing would improve ship performance on 37% of days while the second simulation revealed that weather routing would support ship captains virtually all the time.

  5. Solvent and process for recovery of hydroxide from aqueous mixtures

    DOEpatents

    Moyer, Bruce A.; Chambliss, C. Kevin; Bonnesen, Peter V.; Keever, Tamara J.

    2001-01-01

    Hydroxide values and associated alkali metal may be recovered from alkaline aqueous solutions using classes of fluorinated alcohols in a water immiscible solvent. The alcohols are characterized by fluorine substituents which are proximal to the acidic alcohol protons and are located to adjust the acidity of the extractant and the solubility of the extractant in the solvent. A method for stripping the extractant and solvent to regenerate the extractant and purified aqueous hydroxide solution is described.

  6. Masked Proportional Routing

    NASA Technical Reports Server (NTRS)

    Wolpert, David

    2004-01-01

    Masked proportional routing is an improved procedure for choosing links between adjacent nodes of a network for the purpose of transporting an entity from a source node ("A") to a destination node ("B"). The entity could be, for example, a physical object to be shipped, in which case the nodes would represent waypoints and the links would represent roads or other paths between waypoints. For another example, the entity could be a message or packet of data to be transmitted from A to B, in which case the nodes could be computer-controlled switching stations and the links could be communication channels between the stations. In yet another example, an entity could represent a workpiece while links and nodes could represent, respectively, manufacturing processes and stages in the progress of the workpiece towards a finished product. More generally, the nodes could represent states of an entity and the links could represent allowed transitions of the entity. The purpose of masked proportional routing and of related prior routing procedures is to schedule transitions of entities from their initial states ("A") to their final states ("B") in such a manner as to minimize a cost or to attain some other measure of optimality or efficiency. Masked proportional routing follows a distributed (in the sense of decentralized) approach to probabilistically or deterministically choosing the links. It was developed to satisfy a need for a routing procedure that 1. Does not always choose the same link(s), even for two instances characterized by identical estimated values of associated cost functions; 2. Enables a graceful transition from one set of links to another set of links as the circumstances of operation of the network change over time; 3. Is preferably amenable to separate optimization of different portions of the network; 4. Is preferably usable in a network in which some of the routing decisions are made by one or more other procedure(s); 5. Preferably does not cause an

  7. Electrochemical formation of hydroxide for enhancing carbon dioxide and acid gas uptake by a solution

    DOEpatents

    Rau, Gregory Hudson

    2012-05-15

    A system is described for forming metal hydroxide from a metal carbonate utilizing a water electrolysis cell having an acid-producing anode and a hydroxyl-producing cathode immersed in a water solution of sufficient ionic content to allow an electric current to pass between the hydroxyl-producing cathode and the acid-producing anode. A metal carbonate, in particular water-insoluble calcium carbonate or magnesium carbonate, is placed in close proximity to the acid-producing anode. A direct current electrical voltage is provided across the acid-producing anode and the hydroxyl-producing cathode sufficient to generate acid at the acid-producing anode and hydroxyl ions at the hydroxyl-producing cathode. The acid dissolves at least part of the metal carbonate into metal and carbonate ions allowing the metal ions to travel toward the hydroxyl-producing cathode and to combine with the hydroxyl ions to form the metal hydroxide. The carbonate ions travel toward the acid-producing anode and form carbonic acid and/or water and carbon dioxide. Among other uses, the metal hydroxide formed can be employed to absorb acid gases such as carbon dioxide from a gas mixture. The invention can also generate hydrogen and oxidative gases such as oxygen or chlorine.

  8. Anticancer nanodelivery system with controlled release property based on protocatechuate–zinc layered hydroxide nanohybrid

    PubMed Central

    Barahuie, Farahnaz; Hussein, Mohd Zobir; Abd Gani, Shafinaz; Fakurazi, Sharida; Zainal, Zulkarnain

    2014-01-01

    Background We characterize a novel nanocomposite that acts as an efficient anticancer agent. Methods This nanocomposite consists of zinc layered hydroxide intercalated with protocatechuate (an anionic form of protocatechuic acid), that has been synthesized using a direct method with zinc oxide and protocatechuic acid as precursors. Results The resulting protocatechuic acid nanocomposite (PAN) showed a basal spacing of 12.7 Å, indicating that protocatechuate was intercalated in a monolayer arrangement, with an angle of 54° from the Z-axis between the interlayers of the zinc layered hydroxide, and an estimated drug loading of about 35.7%. PAN exhibited the properties of a mesoporous type material, with greatly enhanced thermal stability of protocatechuate as compared to its free counterpart. The presence of protocatechuate in the interlayers of the zinc layered hydroxide was further supported by Fourier transform infrared spectroscopy. Protocatechuate was released from PAN in a slow and sustained manner. This mechanism of release was well represented by a pseudo-second order kinetics model. PAN has shown increased cytotoxicity compared to the free form of protocatechuic acid in all cancer cell lines tested. Tumor growth suppression was extensive, particularly in HepG2 and HT29 cell lines. Conclusion PAN is suitable for use as a controlled release formulation, and our in vitro evidence indicates that PAN is an effective anticancer agent. PAN may have potential as a chemotherapeutic drug for human cancer. PMID:25061291

  9. Sodium-hydroxide solution treatment on sandstone cores

    SciTech Connect

    Lee, S.J.

    1984-01-01

    This research was performed to study the effect of sodium hydroxide solution on the sandstone core samples and to develop a method whereby the permeability of the samples could be increased by the injection of sodium hydroxide solution. This work should provide the first step in developing a technique that can be used in the stimulation of oil and gas wells. A series of tests was conducted in which sodium hydroxide solution with concentrations ranging from 0.25 N to 2.00 N was injected into a number of Berea sandstone cores. The tests were conducted at room temperature and at 180{degree}F. In some cases the core sample were damaged by the injection of fresh water which resulted in a marked reduction in the permeability of the cores prior to the injection of sodium hydroxide solution. Based on laboratory testing with measurements of uniaxial compressive strength, SEM examination and X-ray analysis, it was found that sodium hydroxide interacted with sandstone to promote (1) partial dissolution of the sandstone minerals; (2) sandstone weight loss; (3) increased porosity; (4) weakening of the sandstone cores; and (5) changes in permeability. The interaction increased with increasing temperature and increasing sodium hydroxide concentration. However, at concentrations higher than 1.00 N, the degree of increase in permeability was not as large even though the sandstone weight loss and the increase in porosity did increase.

  10. The role of calcium hydroxide in the formation of thaumasite

    SciTech Connect

    Bellmann, F. Stark, J.

    2008-10-15

    It has recently been derived by thermodynamic calculation that the presence or absence of calcium hydroxide plays a vital role in the resistance of cement paste or concrete against the formation of thaumasite. To obtain experimental data on this matter, special binders have been mixed and used for the preparation of mortar bars. These specimens were exposed to moderate sulphate attack for a period of 18 months at a temperature of 8 deg. C. Mortar bars containing calcium hydroxide showed visual signs of attack a few months after exposure, leading to expansion, mass loss and complete failure. In contrast to this, no signs of attack were observed when no calcium hydroxide was present in the microstructure. These results confirm the conclusions of earlier thermodynamic calculations that the presence of calcium hydroxide has an important impact on the formation of thaumasite. Calcium-rich C-S-H formed in the presence of calcium hydroxide is vulnerable against sulphate attack and the formation of thaumasite. In the absence of calcium hydroxide, C-S-H has a much lower calcium/silicon ratio and a higher resistance against the formation of thaumasite.

  11. Novel routes to metalloorganics containing aluminum from minerals

    NASA Astrophysics Data System (ADS)

    Narayanan, Ramasubramanian

    Novel pathways for synthesizing Al metalloorganics directly from widely available oxides and oxo-hydroxides of aluminum are developed. The Al metalloorganics are then used to produce low-cost precursors for ceramics and polymers containing Al. Alumatrane, an unique, air-stable, aluminum alkoxide is prepared in one step from aluminum hydroxide in quantitative yields. Subsequently, alumatrane was used to prepare and characterize all group II dialuminate ceramics (MAlsb2Osb4, M = Mg, Ca, Sr, Ba). Similarly, an air-stable alkoxide of silicon was synthesized directly from SiOsb2, and is used in conjunction with alumatrane to produce precursors for aluminosilicate ceramics (MAlSiOsb4, M = K, Li, Na). Aluminum formate is synthesized, in differing efficiencies, from different crystalline minerals of Al, by direct dissolution in formic acid. A few other aluminum carboxylates are also synthesized, either directly from minerals or from aluminum formates, thus expanding the scope of the acid dissolution of aluminum hydroxides. Aluminum allyloxypropanoate (AAP) (Al(Osb2CCHsb2CHsb2OCH{=}CHsb2)sb2(OH)), an aluminum carboxylate with a polymerizable group has been synthesized from aluminum formate. This, has been incorporated into methyl methacrylate (MMA) polymers to impart fire retardancy. The increase in char yields as a result of AAP incorporation, indicate improved fire retardancy. Fire retardant characteristics of alumatrane has also been investigated, in MMA polymers and in a polyurethane polymer, taking char yields as a measure of fire retardance efficiency.

  12. Histological response of human pulps capped with calcium hydroxide and a self-etch adhesive containing an antibacterial component

    PubMed Central

    Parthasarathy, Ambalavanan; Kamat, Sharad B.; Kamat, Mamta; Kidiyoor, Krishnamurthy Haridas

    2016-01-01

    Aim: To compare human pulp tissue response following direct pulp capping with calcium hydroxide and a self-etch adhesive containing antibacterial component. Materials and Methods: Sixty-six erupted sound premolars scheduled to be extracted for orthodontic reasons were selected from 17 human subjects. Pulp exposures were made. Direct pulp capping was then performed using calcium hydroxide and a self-etch adhesive containing antibacterial component in its primer. The teeth were then restored with composite resin. Two teeth were maintained intact as a control group. After 7 and 30 days, teeth were extracted and processed for light microscopic examination using a histological scoring system. The teeth were divided into four groups (N = 16) according to the pulp capping materials used and their days of extraction. The results were then statistically analyzed by Mann-Whitney U-test. Results: After the 7-day observation period, the inflammatory reaction to the self-etch adhesive containing antibacterial component group was significantly less severe than that in the calcium hydroxide group (P < 0.05). After the 30-day observation period, the inflammatory reaction was slight in both groups, but specimens with dentin bridge formation in the self-etch adhesive group were significantly less common than those in the calcium hydroxide group (P < 0.05). PMID:27217644

  13. The Balanced Billing Cycle Vehicle Routing Problem

    SciTech Connect

    Groer, Christopher S; Golden, Bruce; Edward, Wasil

    2009-01-01

    Utility companies typically send their meter readers out each day of the billing cycle in order to determine each customer s usage for the period. Customer churn requires the utility company to periodically remove some customer locations from its meter-reading routes. On the other hand, the addition of new customers and locations requires the utility company to add newstops to the existing routes. A utility that does not adjust its meter-reading routes over time can find itself with inefficient routes and, subsequently, higher meter-reading costs. Furthermore, the utility can end up with certain billing days that require substantially larger meter-reading resources than others. However, remedying this problem is not as simple as it may initially seem. Certain regulatory and customer service considerations can prevent the utility from shifting a customer s billing day by more than a few days in either direction. Thus, the problem of reducing the meterreading costs and balancing the workload can become quite difficult. We describe this Balanced Billing Cycle Vehicle Routing Problem in more detail and develop an algorithm for providing solutions to a slightly simplified version of the problem. Our algorithm uses a combination of heuristics and integer programming via a three-stage algorithm. We discuss the performance of our procedure on a real-world data set.

  14. An Indirect Route for Ethanol Production

    SciTech Connect

    Eggeman, T.; Verser, D.; Weber, E.

    2005-04-29

    The ZeaChem indirect method is a radically new approach to producing fuel ethanol from renewable resources. Sugar and syngas processing platforms are combined in a novel way that allows all fractions of biomass feedstocks (e.g. carbohydrates, lignins, etc.) to contribute their energy directly into the ethanol product via fermentation and hydrogen based chemical process technologies. The goals of this project were: (1) Collect engineering data necessary for scale-up of the indirect route for ethanol production, and (2) Produce process and economic models to guide the development effort. Both goals were successfully accomplished. The projected economics of the Base Case developed in this work are comparable to today's corn based ethanol technology. Sensitivity analysis shows that significant improvements in economics for the indirect route would result if a biomass feedstock rather that starch hydrolyzate were used as the carbohydrate source. The energy ratio, defined as the ratio of green energy produced divided by the amount of fossil energy consumed, is projected to be 3.11 to 12.32 for the indirect route depending upon the details of implementation. Conventional technology has an energy ratio of 1.34, thus the indirect route will have a significant environmental advantage over today's technology. Energy savings of 7.48 trillion Btu/yr will result when 100 MMgal/yr (neat) of ethanol capacity via the indirect route is placed on-line by the year 2010.

  15. Formation of Cr(III) hydroxides from chrome alum solutions. 1: Precipitation of active chromium hydroxide

    SciTech Connect

    Avena, M.J.; Giacomelli, C.E.; De Pauli, C.P.

    1996-06-25

    The hydrolysis of Cr(III) and precipitation of colloidal chromium hydroxides are important processes occurring in soils and natural waters. The formation of active chromium hydroxide, Cr(OH){sub 3}{center_dot}3H{sub 2}O, was studied through potentiometric titrations and turbidimetric measurements. UV-Vis and IR spectroscopies were also employed to characterize the synthesized solid. The rapid addition of NaOH solution to aqueous chrome alum (KCr(SO{sub 4}){sub 2}{center_dot}12H{sub 2}O) solutions caused the immediate precipitation of the active material. Only monomeric Cr(III) species seemed to be participating in the precipitation process; neither chromium polymers nor complexes with anions (SO{sub 4}{sup 2{minus}}, Cl{sup {minus}}, NO{sub 3}{sup {minus}}, ClO{sub 4}{sup {minus}}) influenced the fast formation of Cr(OH){sub 3}{center_dot}3H{sub 2}O. Titration studies allowed the determination of several hydrolysis and precipitation constants for Cr(III). Nevertheless, they cannot be used for the estimate of Cr(OH){sub 3}{sup 0} formation constant.

  16. Pseudo-hydroxide extraction in the separation of sodium hydroxide from aqueous solutions using alkyl phenols

    SciTech Connect

    Kang, Hyun Ah; Moyer, Bruce A

    2006-01-01

    Pseudo-hydroxide extraction of sodium hydroxide from aqueous solution using four alkyl phenols of nearly identical molecular weight in 1-octanol at 25 degrees C was examined to understand the effect of alkyl substituents. The order of extraction strength among the four alkyl phenols tested was 4-tert-octylphenol. 3,5-di-tertbutylphenol. 2,4-di-tert-butylphenol. 2,6-di-tert-butyl-4-methylphenol. A good correlation with phenol pK(a) was observed, indicating that extraction strength is determined by phenol acidity, as modified by steric effects in proximity to the phenol - OH group. The effective partition ratios (P-eff) of two phenols from 1 M NaOH solution were determined, showing that the phenols remain predominantly in the 1-octanol phase even when converted to their sodium salts. However, the hydrophobicity of the tested phenols may not be sufficient for process purposes. The equilibrium constants for the governing extraction equilibria were determined by modeling the data using the program SXLSQI, supporting the cation-exchange extraction mechanism. The proposed mechanism consists of two simple sets of equilibria for a. Ion-pair extraction to give Na+OH- ion pairs and corresponding free ions in 1-octanol the phase and b. Cation exchange by monomeric phenol molecules (HAs) to form monomeric organic-phase Na(+)A(-) ion pairs and corresponding free organic-phase ions.

  17. Layered double hydroxide/polyethylene terephthalate nanocomposites. Influence of the intercalated LDH anion and the type of polymerization heating method

    SciTech Connect

    Herrero, M.; Martinez-Gallegos, S.; Labajos, F.M.; Rives, V.

    2011-11-15

    Conventional and microwave heating routes have been used to prepare PET-LDH (polyethylene terephthalate-layered double hydroxide) composites with 1-10 wt% LDH by in situ polymerization. To enhance the compatibility between PET and the LDH, terephthalate or dodecyl sulphate had been previously intercalated in the LDH. PXRD and TEM were used to detect the degree of dispersion of the filler and the type of the polymeric composites obtained, and FTIR spectroscopy confirmed that the polymerization process had taken place. The thermal stability of these composites, as studied by thermogravimetric analysis, was enhanced when the microwave heating method was applied. Dodecyl sulphate was more effective than terephthalate to exfoliate the samples, which only occurred for the terephthalate ones under microwave irradiation. - Graphical abstract: Conventional and microwave heating routes were used to prepare PET-LDH (polyethylene terephthalate-layered double hydroxide) composites with 1-10 wt% LDH by in situ polymerization. To enhance the compatibility between PET and the LDH, terephthalate or dodecyl sulphate was previously intercalated into the LDH. The microwave process improves the dispersion and the thermal stability of nanocomposites due to the interaction of the microwave radiation and the dipolar properties of EG and the homogeneous heating. Highlights: > LDH-PET compatibility is enhanced by preintercalation of organic anions. > Dodecylsulphate performance is much better than that of terephthalate. > Microwave heating improves the thermal stability of the composites. > Microwave heating improves as well the dispersion of the inorganic phase.

  18. Morphology-controlled nonaqueous synthesis of anisotropic lanthanum hydroxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Djerdj, Igor; Garnweitner, Georg; Sheng Su, Dang; Niederberger, Markus

    2007-07-01

    The preparation of lanthanum hydroxide and manganese oxide nanoparticles is presented, based on a nonaqueous sol-gel process involving the reaction of La(O iPr) 3 and KMnO 4 with organic solvents such as benzyl alcohol, 2-butanone and a 1:1 vol. mixture thereof. The lanthanum manganese oxide system is highly complex and surprising results with respect to product composition and morphology were obtained. In dependence of the reaction parameters, the La(OH) 3 nanoparticles undergo a shape transformation from short nanorods with an average aspect ratio of 2.1 to micron-sized nanofibers (average aspect ratio is more than 59.5). Although not directly involved, KMnO 4 plays a crucial role in determining the particle morphology of La(OH) 3. The reason lies in the fact that KMnO 4 is able to oxidize the benzyl alcohol to benzoic acid, which presumably induces the anisotropic particle growth in [0 0 1] direction upon preferential coordination to the ±(1 0 0), ±(0 1 0) and ±(-110) crystal facets. By adjusting the molar La(O iPr) 3-to-KMnO 4 ratio as well as by using the appropriate solvent mixture it is possible to tailor the morphology, phase purity and microstructure of the La(OH) 3 nanoparticles. Postsynthetic thermal treatment of the sample containing La(OH) 3 nanofibers and β-MnOOH nanoparticles at the temperature of 800 °C for 8 h yielded polyhedral LaMnO 3 and worm-like La 2O 3 nanoparticles as final products.

  19. Robustness of airline route networks

    NASA Astrophysics Data System (ADS)

    Lordan, Oriol; Sallan, Jose M.; Escorihuela, Nuria; Gonzalez-Prieto, David

    2016-03-01

    Airlines shape their route network by defining their routes through supply and demand considerations, paying little attention to network performance indicators, such as network robustness. However, the collapse of an airline network can produce high financial costs for the airline and all its geographical area of influence. The aim of this study is to analyze the topology and robustness of the network route of airlines following Low Cost Carriers (LCCs) and Full Service Carriers (FSCs) business models. Results show that FSC hubs are more central than LCC bases in their route network. As a result, LCC route networks are more robust than FSC networks.

  20. Temperature-mediated phase transformation, pore geometry and pore hysteresis transformation of borohydride derived in-born porous zirconium hydroxide nanopowders

    PubMed Central

    Nayak, Nadiya B.; Nayak, Bibhuti B.

    2016-01-01

    Development of in-born porous nature of zirconium hydroxide nanopowders through a facile hydrogen (H2) gas-bubbles assisted borohydride synthesis route using sodium borohydride (NaBH4) and novel information on the temperature-mediated phase transformation, pore geometry as well as pore hysteresis transformation of in-born porous zirconium hydroxide nanopowders with the help of X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) isotherm and Transmission Electron Microscopy (TEM) images are the main theme of this research work. Without any surfactants or pore forming agents, the borohydride derived amorphous nature of porous powders was stable up to 500 °C and then the seed crystals start to develop within the loose amorphous matrix and trapping the inter-particulate voids, which led to develop the porous nature of tetragonal zirconium oxide at 600 °C and further sustain this porous nature as well as tetragonal phase of zirconium oxide up to 800 °C. The novel hydrogen (H2) gas-bubbles assisted borohydride synthesis route led to develop thermally stable porous zirconium hydroxide/oxide nanopowders with an adequate pore size, pore volume, and surface area and thus these porous materials are further suggested for promising use in different areas of applications. PMID:27198738

  1. Temperature-mediated phase transformation, pore geometry and pore hysteresis transformation of borohydride derived in-born porous zirconium hydroxide nanopowders

    NASA Astrophysics Data System (ADS)

    Nayak, Nadiya B.; Nayak, Bibhuti B.

    2016-05-01

    Development of in-born porous nature of zirconium hydroxide nanopowders through a facile hydrogen (H2) gas-bubbles assisted borohydride synthesis route using sodium borohydride (NaBH4) and novel information on the temperature-mediated phase transformation, pore geometry as well as pore hysteresis transformation of in-born porous zirconium hydroxide nanopowders with the help of X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) isotherm and Transmission Electron Microscopy (TEM) images are the main theme of this research work. Without any surfactants or pore forming agents, the borohydride derived amorphous nature of porous powders was stable up to 500 °C and then the seed crystals start to develop within the loose amorphous matrix and trapping the inter-particulate voids, which led to develop the porous nature of tetragonal zirconium oxide at 600 °C and further sustain this porous nature as well as tetragonal phase of zirconium oxide up to 800 °C. The novel hydrogen (H2) gas-bubbles assisted borohydride synthesis route led to develop thermally stable porous zirconium hydroxide/oxide nanopowders with an adequate pore size, pore volume, and surface area and thus these porous materials are further suggested for promising use in different areas of applications.

  2. Toxicity of triphenyltin hydroxide to fish.

    PubMed

    Antes, Fabiane G; Becker, Alexssandro G; Parodi, Thaylise V; Clasen, Barbara; Lópes, Thais; Loro, Vania L; Baldisserotto, Bernardo; Flores, Erico M M; Dressler, Valderi L

    2013-11-01

    Triphenyltin (TPhT) is used worldwide in pesticide formulas for agriculture. Toxic effects of this compound to aquatic life have been reported; however, the biochemical response of fish exposed to different concentrations of TPhT hydroxide (TPhTH) was investigated for the first time in this study. The lethal concentration (LC50) of TPhTH to silver catfish, Rhamdia quelen, was calculated from an acute-exposure experiment (96 h). In addition, acethylcholinesterase (AChE) activity in brain and muscle-as well as glucose, glycogen, lactate, total protein, ammonia, and free amino acids in liver and muscle-were evaluated in a chronic-exposure experiment (15-day exposure). Speciation analysis of tin (Sn) was performed in fish tissues at the end of both experiments using gas chromatography coupled to a pulsed-flame photometric detector (GC-PFPD). Concentrations of TPhT, diphenyltin, and monophenyltin (reported as Sn) were lower than limits of quantification (10σ criteria). Waterborne TPhTH concentration used through the experiment was also evaluated by GC-PFPD, and no degradation of this species was observed. The LC50 value for silver catfish juveniles was 9.73 μg L(-1) (as Sn). Decreased brain and muscle AChE activities were observed in fish exposed to TPhTH in relation to unexposed fish (control). Liver glycogen and lactate levels were significantly higher in fish kept at the highest waterborne TPhTH concentration compared with the control. Liver and muscle glucose levels of fish exposed to all TPhTH concentrations were significantly lower than those of control fish. Silver catfish exposed to all TPhTH concentrations showed lower total protein values and higher total free amino acids levels in liver and muscle compared with controls. Total ammonia levels in liver and muscle were significantly higher for the highest TPhTH concentration compared with controls. In conclusion, TPhTH caused metabolic alterations in silver catfish juveniles, and the analyzed parameters can

  3. Quaternized graphene oxide nanocomposites as fast hydroxide conductors.

    PubMed

    Zarrin, Hadis; Fu, Jing; Jiang, Gaopeng; Yoo, Skylar; Lenos, Jared; Fowler, Michael; Chen, Zhongwei

    2015-02-24

    Nanocomposites play a key role in performance improvements of hydroxide conductors employed in a wide range of alkaline-electrochemical systems such as fuel cells and metal-air batteries. Graphene oxide (GO) nanosheets are considered to be outstanding nanofillers for polymeric nanocomposites on account of their excellent physicochemical strength and electrochemical properties. In this work, a fast hydroxide conductor was developed on the basis of a chemically modified GO nanocomposite membrane. The high surface area of GO was functionalized with highly stable hydroxide-conductive groups using a dimethyloctadecyl [3-(trimethoxysilyl)propyl]ammonium chloride (DMAOP) precursor, named QAFGO, and then composed with porous polybenzimidazole PBI (pPBI) as a well-suited polymeric backbone. The nanocomposite exhibited outstanding hydroxide conductivity of 0.085 S cm(-1), high physicochemical strength, and electrochemical stability for 21 days. An alkaline fuel cell (AFC) setup was fabricated to determine the functionality of QAFGO/pPBI nanocomposite in an alkaline-based system. The high AFC performance with peak power density of 86.68 mW cm(-2) demonstrated that QAFGO/pPBI nanocomposite membrane has promising potential to be employed as a reliable hydroxide conductor for electrochemical systems working in alkaline conditions. PMID:25644712

  4. [Transient UV absorption spectra of artemisinin reacting with sodium hydroxide].

    PubMed

    Gao, Yan-Jun; Ping, Li; Yang, Li-Jun; Wang, Qi-Ming; Xue, Jun-Peng; Wu, Da-Cheng; Li, Rui-Xia

    2009-03-01

    UV absorption spectrum of artemisinin and transient absorption spectra of various concentrations of artemisinin reacting with sodium hydroxide were measured by using an intensified spectroscopic detector ICCD. The exposure time of each spectrum was 0.1 ms. Results indicate that artemisinin has an obvious UV absorption band centered at 212.52 nm and can react with sodium hydroxide easily. All absorption spectra of different concentrations of artemisinin reacting with sodium hydroxide have the similar changes, but the moment at which the changes happened is different. After adding sodium hydroxide into artemisinin in ethanol solution, there was a new absorption band centered at 288 nm appearing firstly. As reaction went on, the intensity of another absorption band centered at 260 nm increased gradually. At the end of the reaction, a continuous absorption band from 200 to 350 nm with the peak at 245 nm formed finally. No other transient absorption spectral data are available on the reaction of artemisinin with sodium hydroxide currently. The new spectral information obtained in this experiment provides very important experimental basis for understanding the properties of artemisinin reacting with alkaline medium and is useful for correctly using of artemisinin as a potential anticancer drug.

  5. Biocompatibility of Intracanal Medications Based on Calcium Hydroxide

    PubMed Central

    Andolfatto, Carolina; da Silva, Guilherme Ferreira; Cornélio, Ana Livia Gomes; Guerreiro-Tanomaru, Juliane Maria; Tanomaru-Filho, Mario; Faria, Gisele; Bonetti-Filho, Idomeo; Cerri, Paulo Sérgio

    2012-01-01

    Objective. The aim of this study was to evaluate the rat subcutaneous tissue reaction to calcium hydroxide-based intracanal medicaments, UltraCal XS (calcium hydroxide, barium sulphate, aqueous matrix), Hydropast (calcium hydroxide, barium sulphate, and propyleneglycol), and Calen (Calcium hydroxide, zinc oxide, colophony, and polyethyleneglycol), used as a control. Methods. Forty-eight rats (Rattus Norvegicus Holtzman) were distributed in three groups: Calen, UltraCal XS, and Hydropast. Polyethylene tubes filled with one of the medicaments were implanted in the dorsal subcutaneous. After 7 and 30 days, the implants were removed and the specimens were fixed and embedded in paraffin. Morphological and quantitative analyses were carried out in the HE-stained sections. The numerical density of inflammatory cells in the capsule was evaluated and statistical analyses were performed (P ≤ 0.05). Results. At 7 days, all materials induced an inflammatory reaction in the subcutaneous tissue adjacent to the implants. In all groups, a significant reduction in the number of inflammatory cells and giant cells was verified in the period of 30 days. Conclusion. These results indicate that the calcium hydroxide-based medicaments evaluated present biocompatibility similar to Calen. PMID:23320187

  6. New Routing Metrics for ADHOC Network Routing Protocols

    NASA Astrophysics Data System (ADS)

    Reddy, P. C.

    2014-12-01

    The performance and reliability of Internet is measured using different quantities. When the quantities measured are essential and have wide range of acceptance then they are called metrics. Performance metrics enable comparison and selection among the alternatives. In computer networks, metrics are used to evaluate an application, protocol etc. Routing in adhoc networks is nontrivial. Routing protocols for adhoc networks are still evolving and there is need for continuous evaluation of them. In the literature existing, several routing protocols are evaluated using standard metrics under different conditions. This paper proposes new metrics for evaluation of routing protocols and uses them to evaluate the adhoc network routing protocols AODV, DSR, DSDV and TORA. Simulation environment is created using NS-2 simulator. Typical range of speeds, pause times and data rates are used. The results provide new insights in to the working of the routing protocols.

  7. Intelligent route surveillance

    NASA Astrophysics Data System (ADS)

    Schoemaker, Robin; Sandbrink, Rody; van Voorthuijsen, Graeme

    2009-05-01

    Intelligence on abnormal and suspicious behaviour along roads in operational domains is extremely valuable for countering the IED (Improvised Explosive Device) threat. Local sensor networks at strategic spots can gather data for continuous monitoring of daily vehicle activity. Unattended intelligent ground sensor networks use simple sensing nodes, e.g. seismic, magnetic, radar, or acoustic, or combinations of these in one housing. The nodes deliver rudimentary data at any time to be processed with software that filters out the required information. At TNO (Netherlands Organisation for Applied Scientific Research) research has started on how to equip a sensor network with data analysis software to determine whether behaviour is suspicious or not. Furthermore, the nodes should be expendable, if necessary, and be small in size such that they are hard to detect by adversaries. The network should be self-configuring and self-sustaining and should be reliable, efficient, and effective during operational tasks - especially route surveillance - as well as robust in time and space. If data from these networks are combined with data from other remote sensing devices (e.g. UAVs (Unmanned Aerial Vehicles)/aerostats), an even more accurate assessment of the tactical situation is possible. This paper shall focus on the concepts of operation towards a working intelligent route surveillance (IRS) research demonstrator network for monitoring suspicious behaviour in IED sensitive domains.

  8. Standard enthalpies of formation of francium hydroxide hydrates

    SciTech Connect

    Burylev, B.P.

    1995-03-01

    Available experimental data on standard enthalpies of formation of alkali metal hydroxide hydrates have been summarized. Using equations derived, the authors have calculated previously unknown enthalpies of formation of some lithium, sodium, potassium, rubidium, and cesium hydroxide hydrates. Taking into account the contribution of water to the enthalpies of formation of monohydrates, the authors have estimated the enthalpies of formation of francium hydroxide hydrates FrOH{center_dot}H{sub 2}O, FrOH{center_dot}2H{sub 2}O, and FrOH{center_dot}3H{sub 2}O (-745.8, -1085.8, and -1515.8 kJ mol{sup -1}, respectively).

  9. Transformation of zinc hydroxide chloride monohydrate to crystalline zinc oxide.

    PubMed

    Moezzi, Amir; Cortie, Michael; McDonagh, Andrew

    2016-04-25

    Thermal decomposition of layered zinc hydroxide double salts provides an interesting alternative synthesis for particles of zinc oxide. Here, we examine the sequence of changes occurring as zinc hydroxide chloride monohydrate (Zn5(OH)8Cl2·H2O) is converted to crystalline ZnO by thermal decomposition. The specific surface area of the resultant ZnO measured by BET was 1.3 m(2) g(-1). A complicating and important factor in this process is that the thermal decomposition of zinc hydroxide chloride is also accompanied by the formation of volatile zinc-containing species under certain conditions. We show that this volatile compound is anhydrous ZnCl2 and its formation is moisture dependent. Therefore, control of atmospheric moisture is an important consideration that affects the overall efficiency of ZnO production by this process. PMID:27030646

  10. Zinc hydroxide sulphate and its transformation to crystalline zinc oxide.

    PubMed

    Moezzi, Amir; Cortie, Michael B; McDonagh, Andrew M

    2013-10-28

    The thermal transformation of zinc hydroxide sulphate hydrate to zinc oxide has been examined using synchrotron X-ray diffraction, thermogravimetric analysis, scanning electron microscopy, and surface area measurements. By collecting X-ray diffraction data in situ, we found that the dehydration of zinc hydroxide sulphate pentahydrate proceeded in discrete steps to form anhydrous zinc hydroxide sulphate. This compound then decomposed to a mixture of zinc oxide and a compound tentatively identified as Zn3(OH)2(SO4)2 at ~235 °C. At ~360 °C, the final dehydroxylation occurred with the formation of zinc oxy-sulphate, Zn3O(SO4)2, which then decomposed to ZnO at about ~800 °C. Interruption of the dehydration process can be used to synthesize the intermediate compounds.

  11. Sodium hydroxide catalyzed monodispersed high surface area silica nanoparticles

    NASA Astrophysics Data System (ADS)

    Bhakta, Snehasis; Dixit, Chandra K.; Bist, Itti; Abdel Jalil, Karim; Suib, Steven L.; Rusling, James F.

    2016-07-01

    Understanding of the synthesis kinetics and our ability to modulate medium conditions allowed us to generate nanoparticles via an ultra-fast process. The synthesis medium is kept quite simple with tetraethyl orthosilicate (TEOS) as precursor and 50% ethanol and sodium hydroxide catalyst. Synthesis is performed under gentle conditions at 20 °C for 20 min Long synthesis time and catalyst-associated drawbacks are most crucial in silica nanoparticle synthesis. We have addressed both these bottlenecks by replacing the conventional Stober catalyst, ammonium hydroxide, with sodium hydroxide. We have reduced the overall synthesis time from 20 to 1/3 h, ∼60-fold decrease, and obtained highly monodispersed nanoparticles with 5-fold higher surface area than Stober particles. We have demonstrated that the developed NPs with ∼3-fold higher silane can be used as efficient probes for biosensor applications.

  12. Structure and properties of porous ceramics obtained from aluminum hydroxide

    NASA Astrophysics Data System (ADS)

    Levkov, R.; Kulkov, S.

    2016-08-01

    In this paper the study of porous ceramics obtained from aluminum hydroxide with gibbsite modification is presented. The dependence of porosity and mechanical characteristics of the material sintered at different temperatures was studied. It was shown that compressive strength of alumina ceramics increases by 40 times with decreasing the pore volume from 65 to 15%. It was shown that aluminum hydroxide may be used for pore formation and pore volume in the sintered ceramics can be controlled by varying the aluminum hydroxide concentration and sintering temperature. Based on these results one can conclude that the obtained structure is very close to inorganic bone matrix and can be used as promising material for bone implants production.

  13. Asymmetric effect of route-length difference and bottleneck on route choice in two-route traffic system

    NASA Astrophysics Data System (ADS)

    Hino, Yuki; Nagatani, Takashi

    2015-06-01

    We study the traffic behavior in the asymmetric two-route traffic system with real-time information. In the asymmetric two-route system, the length on route A is different from that on route B and there exists a bottleneck on route A. We extend the symmetric two-route dynamic model to the asymmetric case. We investigate the asymmetric effects of the route-length difference and bottleneck on the route choice with real-time information. The travel time on each route depends on the road length, bottleneck, and vehicular density. We derive the dependence of the travel time and mean density on the route-length ratio. We show where, when, and how the congestion occurs by the route choice in the asymmetric two-route system. We clarify the effect of the route-length ratio on the traffic behavior in the route choice.

  14. Effect of oxide formation mechanisms on lead adsorption by biogenic manganese (hydr)oxides, iron (hydr)oxides, and their mixtures.

    PubMed

    Nelson, Yarrow M; Lion, Leonard W; Shuler, Michael L; Ghiorse, William C

    2002-02-01

    The effects of iron and manganese (hydr)oxide formation processes on the trace metal adsorption properties of these metal (hydr)oxides and their mixtures was investigated by measuring lead adsorption by iron and manganese (hydr)oxides prepared by a variety of methods. Amorphous iron (hydr)oxide formed by fast precipitation at pH 7.5 exhibited greater Pb adsorption (gamma(max) = 50 mmol of Pb/mol of Fe at pH 6.0) than iron (hydr)oxide formed by slow, diffusion-controlled oxidation of Fe(II) at pH 4.5-7.0 or goethite. Biogenic manganese(III/IV) (hydr)oxide prepared by enzymatic oxidation of Mn(II) by the bacterium Leptothrix discophora SS-1 adsorbed five times more Pb (per mole of Mn) than an abiotic manganese (hydr)oxide prepared by oxidation of Mn(II) with permanganate, and 500-5000 times more Pb than pyrolusite oxides (betaMnO2). X-ray crystallography indicated that biogenic manganese (hydr)oxide and iron (hydr)oxide were predominantly amorphous or poorly crystalline and their X-ray diffraction patterns were not significantly affected by the presence of the other (hydr)oxide during formation. When iron and manganese (hydr)oxides were mixed after formation, or for Mn biologically oxidized with iron(III) (hydr)oxide present, observed Pb adsorption was similar to that expected for the mixture based on Langmuir parameters for the individual (hydr)oxides. These results indicate that interactions in iron/manganese (hydr)oxide mixtures related to the formation process and sequence of formation such as site masking, alterations in specific surface area, or changes in crystalline structure either did not occur or had a negligible effect on Pb adsorption by the mixtures. PMID:11871557

  15. Effect of oxide formation mechanisms on lead adsorption by biogenic manganese (hydr)oxides, iron (hydr)oxides, and their mixtures.

    PubMed

    Nelson, Yarrow M; Lion, Leonard W; Shuler, Michael L; Ghiorse, William C

    2002-02-01

    The effects of iron and manganese (hydr)oxide formation processes on the trace metal adsorption properties of these metal (hydr)oxides and their mixtures was investigated by measuring lead adsorption by iron and manganese (hydr)oxides prepared by a variety of methods. Amorphous iron (hydr)oxide formed by fast precipitation at pH 7.5 exhibited greater Pb adsorption (gamma(max) = 50 mmol of Pb/mol of Fe at pH 6.0) than iron (hydr)oxide formed by slow, diffusion-controlled oxidation of Fe(II) at pH 4.5-7.0 or goethite. Biogenic manganese(III/IV) (hydr)oxide prepared by enzymatic oxidation of Mn(II) by the bacterium Leptothrix discophora SS-1 adsorbed five times more Pb (per mole of Mn) than an abiotic manganese (hydr)oxide prepared by oxidation of Mn(II) with permanganate, and 500-5000 times more Pb than pyrolusite oxides (betaMnO2). X-ray crystallography indicated that biogenic manganese (hydr)oxide and iron (hydr)oxide were predominantly amorphous or poorly crystalline and their X-ray diffraction patterns were not significantly affected by the presence of the other (hydr)oxide during formation. When iron and manganese (hydr)oxides were mixed after formation, or for Mn biologically oxidized with iron(III) (hydr)oxide present, observed Pb adsorption was similar to that expected for the mixture based on Langmuir parameters for the individual (hydr)oxides. These results indicate that interactions in iron/manganese (hydr)oxide mixtures related to the formation process and sequence of formation such as site masking, alterations in specific surface area, or changes in crystalline structure either did not occur or had a negligible effect on Pb adsorption by the mixtures.

  16. Scalability-performance tradeoffs in MPLS and IP routing

    NASA Astrophysics Data System (ADS)

    Yilmaz, Selma; Matta, Ibrahim

    2002-07-01

    MPLS (Multi-Protocol Label Switching) has recently emerged to facilitate the engineering of network traffic. This can be achieved by directing packet flows over paths that satisfy multiple requirements. MPLS has been regarded as an enhancement to traditional IP routing, which has the following problems: (1) all packets with the same IP destination address have to follow the same path through the network; and (2) paths have often been computed based on static and single link metrics. These problems may cause traffic concentration, and thus degradation in quality of service. In this paper, we investigate by simulations a range of routing solutions and examine the tradeoff between scalability and performance. At one extreme, IP packet routing using dynamic link metrics provides a stateless solution but may lead to routing oscillations. At the other extreme, we consider a recently proposed Profile-based Routing (PBR), which uses knowledge of potential ingress-egress pairs as well as the traffic profile among them. Minimum Interference Routing (MIRA) is another recently proposed MPLS-based scheme, which only exploits knowledge of potential ingress-egress pairs but not their traffic profile. MIRA and the more conventional widest-shortest path (WSP) routing represent alternative MPLS-based approaches on the spectrum of routing solutions. We compare these solutions in terms of utility, bandwidth acceptance ratio as well as their scalability (routing state and computational overhead) and load balancing capability. While the simplest of the per-flow algorithms we consider, the performance of WSP is close to dynamic per-packet routing, without the potential instabilities of dynamic routing.

  17. Southern states` routing agency report

    SciTech Connect

    Not Available

    1989-02-01

    The Southern states` routing agency report is a compendium of 16-southern states` routing programs relative to the transportation of high-level radioactive materials. The report identifies the state-designated routing agencies as defined under 49 Code of Federal Regulations (CFR) Part 171 and provides a reference to the source ad scope of the agencies` rulemaking authority. Additionally, the state agency and contact designated by the state`s governor to receive advance notification and shipment routing information under 10 CFR Parts 71 and 73 are also listed.

  18. Southern States` Routing Agency Report

    SciTech Connect

    Not Available

    1990-03-01

    The Southern States` Routing Agency Report is a compendium of 16-southern states` routing program for the transportation of high-level radioactive materials. The report identifies the state-designated routing agencies as defined under 49 Code of Federal Regulations (CFR) Part 171 and provides a reference to the source and scope of the agencies` rulemaking authority. Additionally, the state agency and contact designated by the state`s governor to receive advance notification and shipment routing information under 10 CFR Parts 71 and 73 are also listed.

  19. Southern states' routing agency report

    SciTech Connect

    Not Available

    1989-02-01

    The Southern states' routing agency report is a compendium of 16-southern states' routing programs relative to the transportation of high-level radioactive materials. The report identifies the state-designated routing agencies as defined under 49 Code of Federal Regulations (CFR) Part 171 and provides a reference to the source ad scope of the agencies' rulemaking authority. Additionally, the state agency and contact designated by the state's governor to receive advance notification and shipment routing information under 10 CFR Parts 71 and 73 are also listed.

  20. Southern States' Routing Agency Report

    SciTech Connect

    Not Available

    1990-03-01

    The Southern States' Routing Agency Report is a compendium of 16-southern states' routing program for the transportation of high-level radioactive materials. The report identifies the state-designated routing agencies as defined under 49 Code of Federal Regulations (CFR) Part 171 and provides a reference to the source and scope of the agencies' rulemaking authority. Additionally, the state agency and contact designated by the state's governor to receive advance notification and shipment routing information under 10 CFR Parts 71 and 73 are also listed.

  1. Scalable room-temperature conversion of copper(II) hydroxide into HKUST-1 (Cu3 (btc)2).

    PubMed

    Majano, Gerardo; Pérez-Ramírez, Javier

    2013-02-20

    Copper(II) hydroxide is converted directly to HKUST-1 (Cu(3) (btc)(2) ) after only 5 min at room-temperature in aqueous ethanolic solution without the need of additional solvents. Scale up to the kilogram scale does not influence porous properties yielding pure-phase product with a remarkable total surface area exceeding 1700 m(2) g(-1) featuring aggregates of nanometer-sized crystals (<600 nm) and extremely high space-time yields.

  2. VHDL Control Routing Simulator

    1995-07-10

    The control router simulates a backplane consisting of up to 16 slot. Slot 0, reserved for a control module (cr-ctrl), generates the system clocks and provides the serial interface to the Gating Logic. The remaining 15 slots (1-15) contain routing modules (cr mod), each having up to 64 serial inputs and outputs with FIFOs. Messages to be transmitted to the Control Router are taken from text files. There are currently 17 such source files. Inmore » the model, the serial output of each source is connected to multiple receivers, so that there are 8 identical messages transmitted to the router for each message file entry.« less

  3. En route noise annoyance laboratory test: Preliminary results

    NASA Technical Reports Server (NTRS)

    Mccurdy, David A.

    1990-01-01

    Until recently concerns about the impact of aircraft noise on people have centered around the takeoff and landing operations of aircraft in the vicinity of airport terminals. The development of the advanced turboprop (propfan) engine, modifications to air corridors, and the desire to maintain a natural environment in national parks and recreation areas have now focused attention on the impact at ground level of the en route noise produced by aircraft at cruise conditions and altitudes. Compared to terminal area noise, en route noise is characterized by relatively low noise levels, lack of high frequency spectral content, and long durations. Much research has been directed towards understanding and quantifying the annoyance caused by terminal area aircraft noise, but relatively little research has been conducted for en route noise. To address this need, a laboratory experiment was conducted to quantify the annoyance of people on the ground to en route noise generated by aircraft at cruise conditions. The objectives of the experiment are to determine the annoyance prediction ability of noise measurement procedures and corrections when applied to en route noise; to determine differences in annoyance response to en route noise and takeoff/landing noise; and to determine differences in annoyance response to advanced turboprop en route noise and conventional jet en route noise.

  4. Operational Evaluatioin of Dynamic Weather Routes at American Airlines

    NASA Technical Reports Server (NTRS)

    McNally, David; Sheth, Kapil; Gong, Chester; Borchers, Paul; Osborne, Jeff; Keany, Desmond; Scott, Brennan; Smith, Steve; Sahlman, Scott; Lee, Chuhan; Cheng, Jinn-Hwei

    2013-01-01

    Dynamic Weather Routes (DWR) is a search engine that continuously and automatically analyzes inflight aircraft in en route airspace and proposes simple route amendments for more efficient routes around convective weather while considering sector congestion, traffic conflicts, and active Special Use Airspace. NASA and American Airlines (AA) are conducting an operational trial of DWR at the AA System Operations Center in Fort Worth, TX. The trial includes only AA flights in Fort Worth Center airspace. Over the period from July 31, 2012 through August 31, 2012, 45% of routes proposed by DWR and evaluated by AA users - air traffic control coordinators and flight dispatchers - were rated as acceptable as proposed or with some modifications. The wind-corrected potential flying time savings for these acceptable routes totals 470 flying min, and results suggest another 1,500 min of potential savings for flights not evaluated due to staffing limitations. A sector congestion analysis shows that in only two out of 83 DWR routes rated acceptable by AA staff were the flights predicted to fly through a congested sector inside of 30 min downstream of present position. This shows that users considered sector congestion data provided by DWR automation and in nearly all cases did not accept routes through over-capacity sectors. It is estimated that 12 AA flights were given reroute clearances as a direct result of DWR for a total savings of 67 flying min.

  5. Experimental study on new route to acetylene by using powder of coal and limestone in plasma reactor

    SciTech Connect

    Wang, Z.; Jin, Z.; Tian, Z.; Yang, Z.; Hao, H.

    1996-12-31

    In this paper, a new route to acetylene is described to use coal and precrushed limestone powder to produce CaC{sub 2}. Also the plasma reactor design is given. The significant advantages over coke and CaO based routes are: (1) the system produces no effluent; (2) coal and limestone as raw material (isn`t CaO); (3) clean fuel gas (H{sub 2}, CO...) that can be burned to provide heat for electricity generator; and (4) calcium hydroxide can be treated with salt to give caustic soda and calcium chloride by products.

  6. Ant navigation: priming of visual route memories.

    PubMed

    Harris, Robert A; Hempel de Ibarra, Natalie; Graham, Paul; Collett, Thomas S

    2005-11-17

    Ants travelling to and fro between their nest and a foraging area may follow stereotyped foodward and homeward routes that are guided by different visual and directional memory sequences. Honeybees are known to fly a feeder-to-hive or hive-to-feeder vector according to whether or not they have recently fed--their feeding state controls which compass direction they select. We show here that the feeding state of the wood ant Formica rufa also determines the choice between an outward or inward journey, but by priming the selective retrieval of visual landmark memories.

  7. Fabrication of Elemental Copper by Intense Pulsed Light Processing of a Copper Nitrate Hydroxide Ink.

    PubMed

    Draper, Gabriel L; Dharmadasa, Ruvini; Staats, Meghan E; Lavery, Brandon W; Druffel, Thad

    2015-08-01

    Printed electronics and renewable energy technologies have shown a growing demand for scalable copper and copper precursor inks. An alternative copper precursor ink of copper nitrate hydroxide, Cu2(OH)3NO3, was aqueously synthesized under ambient conditions with copper nitrate and potassium hydroxide reagents. Films were deposited by screen-printing and subsequently processed with intense pulsed light. The Cu2(OH)3NO3 quickly transformed in less than 100 s using 40 (2 ms, 12.8 J cm(-2)) pulses into CuO. At higher energy densities, the sintering improved the bulk film quality. The direct formation of Cu from the Cu2(OH)3NO3 requires a reducing agent; therefore, fructose and glucose were added to the inks. Rather than oxidizing, the thermal decomposition of the sugars led to a reducing environment and direct conversion of the films into elemental copper. The chemical and physical transformations were studied with XRD, SEM, FTIR and UV-vis. PMID:26154246

  8. Structural Characterization of Aluminum (Oxy)hydroxide Films at the Muscovite (001)-Water Interface.

    PubMed

    Lee, Sang Soo; Schmidt, Moritz; Fister, Timothy T; Nagy, Kathryn L; Sturchio, Neil C; Fenter, Paul

    2016-01-19

    The formation of Al (oxy)hydroxide on the basal surface of muscovite mica was investigated to understand how the structure of the substrate controls the nucleation and growth of secondary phases. Atomic force microscopy images showed that solid phases nucleated on the surface initially as two-dimensional islands that were ≤10 Å in height and ≤200 Å in diameter after 16-50 h of reaction in a 100 μM AlCl3 solution at pH 4.2 at room temperature. High-resolution X-ray reflectivity data indicated that these islands were gibbsite layers whose basic unit is composed of a plane of Al ions octahedrally coordinated to oxygen or hydroxyl groups. The formation of gibbsite layers is likely favored because of the structural similarity between its basal plane and the underlying mica surface. After 700-2000 h of reaction, a thicker and continuous film had formed on top of the initial gibbsite layers. X-ray diffraction data showed that this film was composed of diaspore that grew predominantly with its [040] and [140] crystallographic directions oriented along the muscovite [001] direction. These results show the structural characteristics of the muscovite (001) and Al (oxy)hydroxide film interface where presumed epitaxy had facilitated nucleation of metastable gibbsite layers which acted as a structural anchor for the subsequent growth of thermodynamically stable diaspore grown from a mildly acidic and Al-rich solution. PMID:26681160

  9. Modelling Routes towards Learning Goals

    ERIC Educational Resources Information Center

    Tattersall, Colin; Janssen, Jose; van den Berg, Bert; Koper, Rob

    2006-01-01

    Purpose: This paper aims to define the need for a route modelling language in e-learning, identifying requirements and candidate languages, before providing a recommended approach. Design/methodology/approach: Several sources of requirements are drawn from the literature then used to review available approaches to route modelling. The best…

  10. Producing Gestures Facilitates Route Learning

    PubMed Central

    So, Wing Chee; Ching, Terence Han-Wei; Lim, Phoebe Elizabeth; Cheng, Xiaoqin; Ip, Kit Yee

    2014-01-01

    The present study investigates whether producing gestures would facilitate route learning in a navigation task and whether its facilitation effect is comparable to that of hand movements that leave physical visible traces. In two experiments, we focused on gestures produced without accompanying speech, i.e., co-thought gestures (e.g., an index finger traces the spatial sequence of a route in the air). Adult participants were asked to study routes shown in four diagrams, one at a time. Participants reproduced the routes (verbally in Experiment 1 and non-verbally in Experiment 2) without rehearsal or after rehearsal by mentally simulating the route, by drawing it, or by gesturing (either in the air or on paper). Participants who moved their hands (either in the form of gestures or drawing) recalled better than those who mentally simulated the routes and those who did not rehearse, suggesting that hand movements produced during rehearsal facilitate route learning. Interestingly, participants who gestured the routes in the air or on paper recalled better than those who drew them on paper in both experiments, suggesting that the facilitation effect of co-thought gesture holds for both verbal and nonverbal recall modalities. It is possibly because, co-thought gesture, as a kind of representational action, consolidates spatial sequence better than drawing and thus exerting more powerful influence on spatial representation. PMID:25426624

  11. Dynamic Message Routing Using Processes

    NASA Astrophysics Data System (ADS)

    Scheibler, Thorsten; Karastoyanova, Dimka; Leymann, Frank

    The Enterprise Service Bus (ESB) is composable middleware that provides applications with services such as message routing and transformation, service composition, dynamic discovery, transactional support, coordination, security features, and others. In an ESB supporting SOAP message exchange, routing algorithms typically follow the sequential SOAP message processing model, where SOAP headers are the main artefacts used to specify the message route and the processing of the payload by intermediaries along that route. This model supports neither alternative nor parallel message routes. In the case of a failing intermediary node this leads to a failure in the message delivery. Moreover, the execution order of services on SOAP message payloads at the intermediaries cannot be prescribed. In this paper, we demonstrate how these deficiencies of the SOAP message processing model can be addressed. We introduce an approach that allows for specifying SOAP message routing logic in terms of BPEL processes. We show that parallel and alternative routes for SOAP messages can be modelled and executed, and the order of services that process a message at intermediaries can be predefined to accommodate the correct processing sequence as required by the concrete application domain. Features like dynamic discovery of services and flexible service composition are leveraged to enable flexible SOAP message routing.

  12. Producing gestures facilitates route learning.

    PubMed

    So, Wing Chee; Ching, Terence Han-Wei; Lim, Phoebe Elizabeth; Cheng, Xiaoqin; Ip, Kit Yee

    2014-01-01

    The present study investigates whether producing gestures would facilitate route learning in a navigation task and whether its facilitation effect is comparable to that of hand movements that leave physical visible traces. In two experiments, we focused on gestures produced without accompanying speech, i.e., co-thought gestures (e.g., an index finger traces the spatial sequence of a route in the air). Adult participants were asked to study routes shown in four diagrams, one at a time. Participants reproduced the routes (verbally in Experiment 1 and non-verbally in Experiment 2) without rehearsal or after rehearsal by mentally simulating the route, by drawing it, or by gesturing (either in the air or on paper). Participants who moved their hands (either in the form of gestures or drawing) recalled better than those who mentally simulated the routes and those who did not rehearse, suggesting that hand movements produced during rehearsal facilitate route learning. Interestingly, participants who gestured the routes in the air or on paper recalled better than those who drew them on paper in both experiments, suggesting that the facilitation effect of co-thought gesture holds for both verbal and nonverbal recall modalities. It is possibly because, co-thought gesture, as a kind of representational action, consolidates spatial sequence better than drawing and thus exerting more powerful influence on spatial representation. PMID:25426624

  13. Dewatering of alumino-humic sludge: impacts of hydroxide.

    PubMed

    Bache, D H; Papavasilopoulos, E N

    2003-08-01

    The paper draws together information on factors which influence the conditioning and dewatering behaviour of an alum sludge gained from the coagulation of a low-turbidity coloured water. A principal focus is the potential impact of aluminium hydroxide on the sludge character. Background information is provided on the composition of the source floc for the domain pH 6.0-6.5 and Al>2.0mg/l. From this, there were many pointers to the presence of Al(OH)(3)(s) within the floc. A series of comparisons were made between an alum sludge and a hydroxide suspension at a concentration equivalent to the coagulant fraction within the sludge. The parameters studied included floc size, floc density, polymer adsorption and dewatering behaviour at different time-scales. In all cases, there were strong similarities in the behaviour of the two suspensions-indicating the potential impact of the hydroxide. There was also evidence of common features being displayed by both the organic fractions and the hydroxide. It was suggested that some of the behavioural features might emanate from a common fractal structure within the source floc, the fractal dimension (approximately 1) being insensitive to composition.

  14. Sintering of corundum ceramics based on aluminum hydroxide

    SciTech Connect

    Afoninia, G.A.; Leonov, V.G.

    1995-09-01

    The possibility of using aluminum hydroxide obtained by the precipitation method for synthesis of corundum ceramics with additives forming a liquid phase during firing and without additives, is investigated. The optimum parameters of the manufacturing process and the main properties of the material recommended for testing in the production of glass ceramic substrates for integrated circuits are investigated.

  15. Aqueous alkali metal hydroxide insoluble cellulose ether membrane

    NASA Technical Reports Server (NTRS)

    Hoyt, H. E.; Pfluger, H. L. (Inventor)

    1969-01-01

    A membrane that is insoluble in an aqueous alkali metal hydroxide medium is described. The membrane is a resin which is a water-soluble C2-C4 hydroxyalkyl cellulose ether polymer and an insolubilizing agent for controlled water sorption, a dialytic and electrodialytic membrane. It is particularly useful as a separator between electrodes or plates in an alkaline storage battery.

  16. Praseodymium(III) sulfate hydroxide, Pr(SO(4))(OH).

    PubMed

    Wang, Xiao-Juan; Cheng, Jian-Wen

    2011-01-15

    The title compound, Pr(SO(4))(OH), obtained under hydro-thermal conditions, consists of Pr(III) ions coordinated by nine O atoms from six sulfate groups and three hydroxide anions. The bridging mode of the O atoms results in the formation of a three-dimensional framework, stabilized by two O-H⋯O hydrogen-bonding inter-actions.

  17. Engineering evaluation of a sodium hydroxide thermal energy storage module

    NASA Technical Reports Server (NTRS)

    Perdue, D. G.; Gordon, L. H.

    1980-01-01

    An engineering evaluation of thermal energy storage prototypes was performed in order to assess the development status of latent heat storage media. The testing and the evaluation of a prototype sodium hydroxide module is described. This module stored off-peak electrical energy as heat for later conversion to domestic hot water needs.

  18. Nickel immobilization in ceramic matrix admixed with waste nickel hydroxide.

    PubMed

    Osińska, Malgorzata; Stefanowicz, Tadeusz; Paukszta, Dominik

    2003-01-01

    WAXS examinations performed with nickel hydroxide samples heated to various temperatures showed that freshly settled wet nickel hydroxide sample contains some amount of crystalline beta-Ni(OH)(2) structure and its share increased when sample was dried during 3 weeks at ambient temperature. However, the share significantly decreased when the sample was dried at 110 degrees C and more so at 250 degrees C. Crystalline phase traces of Ni(OH)(2) disappeared after sample burning at 980 degrees C and instead the distinct presence of crystalline NiO was determined. The above samples were examined for solubility in stoichiometric amount of sulphuric acid diluted with water to pH 1.9 and 2.8. Solubility was determined by measuring nickel ion concentration in leachate by the AAS method. The dissolving rate was found to decrease with the rise of temperature to which the nickel hydroxide samples were heated. The solubility of Ni(OH)(2) sample burnt at 980 degrees C was undetectable during 90 h solubility-testing time likely due to its transformation into sparingly soluble crystalline NiO. The latter is considered to be the reason for effective immobilization of waste nickel hydroxide in ceramic prepared by blending with clay and sintering at 980 degrees C. PMID:14583250

  19. Chemical analysis of the liberation of calcium and hydroxyl ions from calcium hydroxide pastes in connective tissue in the dog--Part I.

    PubMed

    Estrela, C; Pesce, H F

    1996-01-01

    The objective of this research is to chemically analyze calcium hydroxide pastes added to three hydrosoluble vehicles having different acid-base characteristics using polyethylene tubes implanted in subcutaneous connective tissue in a dog, evaluating the liberation of calcium and hydroxyl ions over a period of 7, 30, 45 and 60 days. The three vehicles were saline, anesthetic, and polyethylene glycol 400. Chemical analysis of the liberated calcium ions was done by means of conductimetry using EDTA for titration. Liberation of hydroxyl ions was determined by analogy of calcium ions liberated, which are in direct proportion to the molecular weight of calcium hydroxide.

  20. 21 CFR 184.1139 - Ammonium hydroxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... by passing ammonia gas into water. (b) The ingredient meets the specifications of the Food Chemicals..._regulations/ibr_locations.html. (c) In accordance with § 184.1(b)(1), the ingredient is used in food with no... recognized as safe (GRAS) as a direct human food ingredient is based upon the following current...

  1. 40 CFR 721.10573 - Magnesium hydroxide surface treated with substituted alkoxysilanes (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Magnesium hydroxide surface treated... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10573 Magnesium hydroxide surface... to reporting. (1) The chemical substance identified generically as magnesium hydroxide...

  2. 40 CFR 721.10573 - Magnesium hydroxide surface treated with substituted alkoxysilanes (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Magnesium hydroxide surface treated... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10573 Magnesium hydroxide surface... to reporting. (1) The chemical substance identified generically as magnesium hydroxide...

  3. 40 CFR 415.310 - Applicability; description of the calcium hydroxide production subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... calcium hydroxide production subcategory. 415.310 Section 415.310 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Calcium Hydroxide Production Subcategory § 415.310 Applicability; description of the calcium hydroxide production subcategory. The provisions of this subpart are applicable to...

  4. 40 CFR 415.310 - Applicability; description of the calcium hydroxide production subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... calcium hydroxide production subcategory. 415.310 Section 415.310 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Calcium Hydroxide Production Subcategory § 415.310 Applicability; description of the calcium hydroxide production subcategory. The provisions of this subpart are applicable to...

  5. 40 CFR 415.310 - Applicability; description of the calcium hydroxide production subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... calcium hydroxide production subcategory. 415.310 Section 415.310 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Calcium Hydroxide Production Subcategory § 415.310 Applicability; description of the calcium hydroxide production subcategory. The provisions of this subpart are applicable to...

  6. 40 CFR 415.310 - Applicability; description of the calcium hydroxide production subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... calcium hydroxide production subcategory. 415.310 Section 415.310 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Calcium Hydroxide Production Subcategory § 415.310 Applicability; description of the calcium hydroxide production subcategory. The provisions of this subpart are applicable to...

  7. 40 CFR 415.310 - Applicability; description of the calcium hydroxide production subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... calcium hydroxide production subcategory. 415.310 Section 415.310 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Calcium Hydroxide Production Subcategory § 415.310 Applicability; description of the calcium hydroxide production subcategory. The provisions of this subpart are applicable to...

  8. DOUBLE SHELL TANK (DST) HYDROXIDE DEPLETION MODEL FOR CARBON DIOXIDE ABSORPTION

    SciTech Connect

    OGDEN DM; KIRCH NW

    2007-10-31

    This document generates a supernatant hydroxide ion depletion model based on mechanistic principles. The carbon dioxide absorption mechanistic model is developed in this report. The report also benchmarks the model against historical tank supernatant hydroxide data and vapor space carbon dioxide data. A comparison of the newly generated mechanistic model with previously applied empirical hydroxide depletion equations is also performed.

  9. Potassium hydroxide: an alternative reagent to perform the modified apt test.

    PubMed

    Chicaiza, Henry; Hellstrand, Karl; Lerer, Trudy; Smith, Sharon; Sylvester, Francisco

    2014-09-01

    We tested the performance of potassium hydroxide (KOH) in the modified Apt test under different experimental conditions using sodium hydroxide as a positive control. Like sodium hydroxide, KOH differentiated fresh fetal and adult blood stains on a cloth but not dried blood. KOH may be used to perform the Apt test at the bedside.

  10. How desert ants use a visual landmark for guidance along a habitual route.

    PubMed

    Collett, Matthew

    2010-06-22

    Many animals learn to follow habitual routes between important locations, but how they encode their routes is still largely unknown. Desert ants traveling between their nest and a food site develop stable, visually guided routes that can wind through desert scrub without the use of trail pheromones. Their route memories are sufficiently robust that if a nest-bound ant is caught at the end of its route and replaced somewhere earlier along it, the ant will recapitulate the route from the release site. Insects appear to use panoramas to recognize when they are on a familiar route. I examine here the cues then used for their guidance. Several mechanisms are known for straight segments of a route; but how does an ant encode a curved route along which both the views it sees, and the directions it takes, are constantly changing? The results here suggest that when an ant travels past a landmark on a familiar route, it uses the gradually changing direction of the landmark to trigger a set of associated learned heading directions. A route through a complex 2D environment could thus be encoded and followed economically if it is divided into panorama-defined segments, with each segment controlled by such a 1D mapping. The solution proposed for the ants would be simple to implement in an autonomous robot. PMID:20534539

  11. Past Tense Route Priming

    PubMed Central

    Cohen-Shikora, Emily R.; Balota, David A.

    2013-01-01

    The present research examined whether lexical (whole word) or more rule-based (morphological constituent) processes can be locally biased by experimental list context in past tense verb inflection. In Experiment 1, younger and older adults completed a past tense inflection task in which list context was manipulated across blocks containing regular past tense verbs (e.g. REACH-REACHED) or irregular past tense verbs (TEACH-TAUGHT). Critical targets, consisting of half regular and half irregular verbs, were embedded within blocks and participants' inflection response latency and accuracy were assessed. The results yielded a cross-over interaction in response latencies. In the regular context there was a robust regularity effect: regular target verbs were conjugated faster than irregular target verbs. In contrast, in the irregular context, irregular target verbs were conjugated faster than regular target verbs. Experiment 2 used the same targets but in the context of either standard nonwords or nonwords ending in “-ED” to test the possibility of a phonological basis for the effect. The effect of context was eliminated. The results support the notion that distinct processes in past tense verb production can be locally biased by list context and, as shown in Experiment 2, this route priming effect was not due to phonological priming. PMID:23291293

  12. Highly active and durable methanol oxidation electrocatalyst based on the synergy of platinum-nickel hydroxide-graphene.

    PubMed

    Huang, Wenjing; Wang, Hongtao; Zhou, Jigang; Wang, Jian; Duchesne, Paul N; Muir, David; Zhang, Peng; Han, Na; Zhao, Feipeng; Zeng, Min; Zhong, Jun; Jin, Chuanhong; Li, Yanguang; Lee, Shuit-Tong; Dai, Hongjie

    2015-11-25

    Active and durable electrocatalysts for methanol oxidation reaction are of critical importance to the commercial viability of direct methanol fuel cell technology. Unfortunately, current methanol oxidation electrocatalysts fall far short of expectations and suffer from rapid activity degradation. Here we report platinum-nickel hydroxide-graphene ternary hybrids as a possible solution to this long-standing issue. The incorporation of highly defective nickel hydroxide nanostructures is believed to play the decisive role in promoting the dissociative adsorption of water molecules and subsequent oxidative removal of carbonaceous poison on neighbouring platinum sites. As a result, the ternary hybrids exhibit exceptional activity and durability towards efficient methanol oxidation reaction. Under periodic reactivations, the hybrids can endure at least 500,000 s with negligible activity loss, which is, to the best of our knowledge, two to three orders of magnitude longer than all available electrocatalysts.

  13. Sorptive stabilization of organic matter by amorphous Al hydroxide

    NASA Astrophysics Data System (ADS)

    Schneider, M. P. W.; Scheel, T.; Mikutta, R.; van Hees, P.; Kaiser, K.; Kalbitz, K.

    2010-03-01

    Amorphous Al hydroxides (am-Al(OH) 3) strongly sorb and by this means likely protect dissolved organic matter (OM) against microbial decay in soils. We carried out batch sorption experiments (pH 4.5; 40 mg organic C L -1) with OM extracted from organic horizons under a Norway spruce and a European beech forest. The stabilization of OM by sorption was analyzed by comparing the CO 2 mineralized during the incubation of sorbed and non-sorbed OM. The mineralization of OM was evaluated based in terms of (i) the availability of the am-Al(OH) 3, thus surface OM loadings, (ii) spectral properties of OM, and (iii) the presence of phosphate as a competitor for OM. This was done by varying the solid-to-solution ratio (SSR = 0.02-1.2 g L -1) during sorption. At low SSRs, hence limited am-Al(OH) 3 availability, only small portions of dissolved OM were sorbed; for OM from Oa horizons, the mineralization of the sorbed fraction exceeded that of the original dissolved OM. The likely reason is competition with phosphate for sorption sites favouring the formation of weak mineral-organic bindings and the surface accumulation of N-rich, less aromatic and less complex OM. This small fraction controlled the mineralization of sorbed OM even at higher SSRs. At higher SSRs, i.e., with am-Al(OH) 3 more available, competition of phosphate decreased and aromatic compounds were sorbed selectively, which resulted in pronounced resistance of sorbed OM against decay. The combined OC mineralization of sorbed and non-sorbed OM was 12-65% less than that of the original DOM. Sorbed OM contributed only little to the overall OC mineralization. Stabilization of OC increased in direct proportion to am-Al(OH) 3 availability, despite constant aromatic C (˜30%). The strong stabilization at higher mineral availability is primarily governed by strong Al-OM bonds formed under less competitive conditions. Due to these strong bonds and the resulting strong stabilization, the surface loading, a proxy for the

  14. 49 CFR 236.767 - Locking, route.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Locking, route. Electric locking, effective when a train passes a signal displaying an aspect for it to... within the route entered. It may be so arranged that as a train clears a track section of the route,...

  15. 49 CFR 236.767 - Locking, route.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Locking, route. Electric locking, effective when a train passes a signal displaying an aspect for it to... within the route entered. It may be so arranged that as a train clears a track section of the route,...

  16. Hexagonal ZnO porous plates prepared from microwave synthesized layered zinc hydroxide sulphate via thermal decomposition

    SciTech Connect

    Machovsky, Michal; Kuritka, Ivo; Sedlak, Jakub; Pastorek, Miroslav

    2013-10-15

    Graphical abstract: - Highlights: • Zinc hydroxy sulphate was synthesized in 3 min via microwave hydrothermal route. • Zinc hydroxy sulphate was converted into mesh like porous ZnO by calcining at 900°. • The process of transformation is topotactic. - Abstract: Layered zinc hydroxide sulphate (ZHS) was prepared by microwave-assisted hydrothermal precipitation of zinc sulphate monohydrate with hexamethylenetetramine. Under ambient conditions, the structure of ZHS determined by X-ray diffraction (XRD) was found to be a mixture of zinc hydroxide sulphate pentahydrate Zn{sub 4}SO{sub 4}(OH){sub 6}·5H{sub 2}O and tetrahydrate Zn{sub 4}SO{sub 4}(OH){sub 6}·4H{sub 2}O. Fourier transform infrared (FTIR) spectroscopy was used for characterization of the prepared materials. Based on the interpretation of ZHS's thermal decomposition profile obtained by thermogravimetric analysis, ZnO of high purity was prepared by calcination at 900 °C for 2 h. The structure of the resulting ZnO was confirmed by the XRD. The morphology examination by scanning electron microscopy revealed a porous mesh-like ZnO structure developed from the ZHS precursor at the expense of mass removal due to the release of water and sulphate during the calcination.

  17. Routing and Scheduling Algorithms for WirelessHARTNetworks: A Survey.

    PubMed

    Nobre, Marcelo; Silva, Ivanovitch; Guedes, Luiz Affonso

    2015-01-01

    Wireless communication is a trend nowadays for the industrial environment. A number of different technologies have emerged as solutions satisfying strict industrial requirements (e.g., WirelessHART, ISA100.11a, WIA-PA). As the industrial environment presents a vast range of applications, adopting an adequate solution for each case is vital to obtain good performance of the system. In this context, the routing and scheduling schemes associated with these technologies have a direct impact on important features, like latency and energy consumption. This situation has led to the development of a vast number of routing and scheduling schemes. In the present paper, we focus on the WirelessHART technology, emphasizing its most important routing and scheduling aspects in order to guide both end users and the developers of new algorithms. Furthermore, we provide a detailed literature review of the newest routing and scheduling techniques forWirelessHART, discussing each of their features. These routing algorithms have been evaluated in terms of their objectives, metrics, the usage of theWirelessHART structures and validation method. In addition, the scheduling algorithms were also evaluated by metrics, validation, objectives and, in addition, by multiple superframe support, as well as by the redundancy method used. Moreover, this paper briefly presents some insights into the main WirelessHART simulation modules available, in order to provide viable test platforms for the routing and scheduling algorithms. Finally, some open issues in WirelessHART routing and scheduling algorithms are discussed. PMID:25919371

  18. Routing and Scheduling Algorithms for WirelessHARTNetworks: A Survey.

    PubMed

    Nobre, Marcelo; Silva, Ivanovitch; Guedes, Luiz Affonso

    2015-01-01

    Wireless communication is a trend nowadays for the industrial environment. A number of different technologies have emerged as solutions satisfying strict industrial requirements (e.g., WirelessHART, ISA100.11a, WIA-PA). As the industrial environment presents a vast range of applications, adopting an adequate solution for each case is vital to obtain good performance of the system. In this context, the routing and scheduling schemes associated with these technologies have a direct impact on important features, like latency and energy consumption. This situation has led to the development of a vast number of routing and scheduling schemes. In the present paper, we focus on the WirelessHART technology, emphasizing its most important routing and scheduling aspects in order to guide both end users and the developers of new algorithms. Furthermore, we provide a detailed literature review of the newest routing and scheduling techniques forWirelessHART, discussing each of their features. These routing algorithms have been evaluated in terms of their objectives, metrics, the usage of theWirelessHART structures and validation method. In addition, the scheduling algorithms were also evaluated by metrics, validation, objectives and, in addition, by multiple superframe support, as well as by the redundancy method used. Moreover, this paper briefly presents some insights into the main WirelessHART simulation modules available, in order to provide viable test platforms for the routing and scheduling algorithms. Finally, some open issues in WirelessHART routing and scheduling algorithms are discussed.

  19. Network-wide BGP route prediction for traffic engineering

    NASA Astrophysics Data System (ADS)

    Feamster, Nick; Rexford, Jennifer

    2002-07-01

    The Internet consists of about 13,000 Autonomous Systems (AS's) that exchange routing information using the Border Gateway Protocol (BGP). The operators of each AS must have control over the flow of traffic through their network and between neighboring AS's. However, BGP is a complicated, policy-based protocol that does not include any direct support for traffic engineering. In previous work, we have demonstrated that network operators can adapt the flow of traffic in an efficient and predictable fashion through careful adjustments to the BGP policies running on their edge routers. Nevertheless, many details of the BGP protocol and decision process make predicting the effects of these policy changes difficult. In this paper, we describe a tool that predicts traffic flow at network exit points based on the network topology, the import policy associated with each BGP session, and the routing advertisements received from neighboring AS's. We present a linear-time algorithm that computes a network-wide view of the best BGP routes for each destination prefix given a static snapshot of the network state, without simulating the complex details of BGP message passing. We describe how to construct this snapshot using the BGP routing tables and router configuration files available from operational routers. We verify the accuracy of our algorithm by applying our tool to routing and configuration data from AT&T's commercial IP network. Our route prediction techniques help support the operation of large IP backbone networks, where interdomain routing is an important aspect of traffic engineering.

  20. Inverse hydrograph routing optimization model based on the kinematic wave approach

    NASA Astrophysics Data System (ADS)

    Saghafian, B.; Jannaty, M. H.; Ezami, N.

    2015-08-01

    This article presents and validates the inverse flood hydrograph routing optimization model under kinematic wave (KW) approximation in order to produce the upstream (inflow) hydrograph, given the downstream (outflow) hydrograph of a river reach. The cost function involves minimization of the error between the observed outflow hydrograph and the corresponding directly routed outflow hydrograph. Decision variables are the inflow hydrograph ordinates. The KW and genetic algorithm (GA) are coupled, representing the selected methods of direct routing and optimization, respectively. A local search technique is also enforced to achieve better agreement of the routed outflow hydrograph with the observed hydrograph. Computer programs handling the direct flood routing, cost function and local search are linked with the optimization model. The results show that the case study inflow hydrographs obtained by the GA were reconstructed with accuracy. It was also concluded that the coupled KW-GA model framework can perform inverse hydrograph routing with numerical stability.

  1. Magnetotactic bacteria form magnetite from a phosphate-rich ferric hydroxide via nanometric ferric (oxyhydr)oxide intermediates

    PubMed Central

    Baumgartner, Jens; Morin, Guillaume; Menguy, Nicolas; Perez Gonzalez, Teresa; Widdrat, Marc; Cosmidis, Julie; Faivre, Damien

    2013-01-01

    The iron oxide mineral magnetite (Fe3O4) is produced by various organisms to exploit magnetic and mechanical properties. Magnetotactic bacteria have become one of the best model organisms for studying magnetite biomineralization, as their genomes are sequenced and tools are available for their genetic manipulation. However, the chemical route by which magnetite is formed intracellularly within the so-called magnetosomes has remained a matter of debate. Here we used X-ray absorption spectroscopy at cryogenic temperatures and transmission electron microscopic imaging techniques to chemically characterize and spatially resolve the mechanism of biomineralization in those microorganisms. We show that magnetite forms through phase transformation from a highly disordered phosphate-rich ferric hydroxide phase, consistent with prokaryotic ferritins, via transient nanometric ferric (oxyhydr)oxide intermediates within the magnetosome organelle. This pathway remarkably resembles recent results on synthetic magnetite formation and bears a high similarity to suggested mineralization mechanisms in higher organisms. PMID:23980143

  2. Magnetotactic bacteria form magnetite from a phosphate-rich ferric hydroxide via nanometric ferric (oxyhydr)oxide intermediates.

    PubMed

    Baumgartner, Jens; Morin, Guillaume; Menguy, Nicolas; Perez Gonzalez, Teresa; Widdrat, Marc; Cosmidis, Julie; Faivre, Damien

    2013-09-10

    The iron oxide mineral magnetite (Fe3O4) is produced by various organisms to exploit magnetic and mechanical properties. Magnetotactic bacteria have become one of the best model organisms for studying magnetite biomineralization, as their genomes are sequenced and tools are available for their genetic manipulation. However, the chemical route by which magnetite is formed intracellularly within the so-called magnetosomes has remained a matter of debate. Here we used X-ray absorption spectroscopy at cryogenic temperatures and transmission electron microscopic imaging techniques to chemically characterize and spatially resolve the mechanism of biomineralization in those microorganisms. We show that magnetite forms through phase transformation from a highly disordered phosphate-rich ferric hydroxide phase, consistent with prokaryotic ferritins, via transient nanometric ferric (oxyhydr)oxide intermediates within the magnetosome organelle. This pathway remarkably resembles recent results on synthetic magnetite formation and bears a high similarity to suggested mineralization mechanisms in higher organisms.

  3. Magnetotactic bacteria form magnetite from a phosphate-rich ferric hydroxide via nanometric ferric (oxyhydr)oxide intermediates.

    PubMed

    Baumgartner, Jens; Morin, Guillaume; Menguy, Nicolas; Perez Gonzalez, Teresa; Widdrat, Marc; Cosmidis, Julie; Faivre, Damien

    2013-09-10

    The iron oxide mineral magnetite (Fe3O4) is produced by various organisms to exploit magnetic and mechanical properties. Magnetotactic bacteria have become one of the best model organisms for studying magnetite biomineralization, as their genomes are sequenced and tools are available for their genetic manipulation. However, the chemical route by which magnetite is formed intracellularly within the so-called magnetosomes has remained a matter of debate. Here we used X-ray absorption spectroscopy at cryogenic temperatures and transmission electron microscopic imaging techniques to chemically characterize and spatially resolve the mechanism of biomineralization in those microorganisms. We show that magnetite forms through phase transformation from a highly disordered phosphate-rich ferric hydroxide phase, consistent with prokaryotic ferritins, via transient nanometric ferric (oxyhydr)oxide intermediates within the magnetosome organelle. This pathway remarkably resembles recent results on synthetic magnetite formation and bears a high similarity to suggested mineralization mechanisms in higher organisms. PMID:23980143

  4. Self-assembled 3D flower-like Ni2+-Fe3+ layered double hydroxides and their calcined products.

    PubMed

    Xiao, Ting; Tang, Yiwen; Jia, Zhiyong; Li, Dawei; Hu, Xiaoyan; Li, Bihui; Luo, Lijuan

    2009-11-25

    This paper describes a facile solvothermal method to synthesize self-assembled three-dimensional (3D) Ni2+-Fe3+ layered double hydroxides (LDHs). Flower-like Ni2+-Fe3+ LDHs constructed of thin nanopetals were obtained using ethylene glycol (EG) as a chelating reagent and urea as a hydrolysis agent. The reaction mechanism and self-assembly process are discussed. After calcinating the as-prepared LDHs at 450 degrees C in nitrogen gas, porous NiO/NiFe2O4 nanosheets were obtained. This work resulted in the development of a simple, cheap, and effective route for the fabrication of large area Ni2+-Fe3+ LDHs as well as porous NiO/NiFe2O4 nanosheets. PMID:19858561

  5. Synthesis of layered double hydroxide nanosheets by coprecipitation using a T-type microchannel reactor

    SciTech Connect

    Pang, Xiujiang; Sun, Meiyu; Ma, Xiuming; Hou, Wanguo

    2014-02-15

    The synthesis of Mg{sub 2}Al–NO{sub 3} layered double hydroxide (LDH) nanosheets by coprecipitation using a T-type microchannel reactor is reported. Aqueous LDH nanosheet dispersions were obtained. The LDH nanosheets were characterized by X-ray diffraction, transmission electron microscopy, atomic force microscopy and particle size analysis, and the transmittance and viscosity of LDH nanosheet dispersions were examined. The two-dimensional LDH nanosheets consisted of 1–2 brucite-like layers and were stable for ca. 16 h at room temperature. In addition, the co-assembly between LDH nanosheets and dodecyl sulfate (DS) anions was carried out, and a DS intercalated LDH nanohybrid was obtained. To the best of our knowledge, this is the first report of LDH nanosheets being directly prepared in bulk aqueous solution. This simple, cheap method can provide naked LDH nanosheets in high quantities, which can be used as building blocks for functional materials. - Graphical abstract: Layered double hydroxide (LDH) nanosheets were synthesized by coprecipitation using a T-type microchannel reactor, and could be used as basic building blocks for LDH-based functional materials. Display Omitted - Highlights: • LDH nanosheets were synthesized by coprecipitation using a T-type microchannel reactor. • Naked LDH nanosheets were dispersed in aqueous media. • LDH nanosheets can be used as building blocks for functional materials.

  6. Treatment of rheumatoid synovitis of the knee with intraarticular injection of dysprosium 165-ferric hydroxide macroaggregates

    SciTech Connect

    Sledge, C.B.; Zuckerman, J.D.; Zalutsky, M.R.; Atcher, R.W.; Shortkroff, S.; Lionberger, D.R.; Rose, H.A.; Hurson, B.J.; Lankenner, P.A. Jr.; Anderson, R.J.

    1986-02-01

    One hundred eight knees of 93 patients with seropositive rheumatoid arthritis and persistent synovitis of the knee were treated with an intraarticular injection of 270 mCi of dysprosium 165 bound to ferric hydroxide macroaggregate. Leakage of radioactivity from the injected joint was minimal. Mean leakage to the venous blood 3 hours after injection was 0.11% of the injected dose; this corresponds to a mean whole body dose of 0.2 rads. Mean leakage to the liver 24 hours after injection was 0.64% of the injected dose; this corresponds to a mean liver dose of 3.2 rads. In 7 additional patients examined, there was negligible or near negligible activity found in the draining inguinal lymph nodes. One-year followup was possible for 74 knees (63 patients). Sixty-one percent of the knees had good results, 23% had fair results, and 16% had poor results. There was a direct correlation between the radiographic stage and response to treatment. In knees with stage I radiographic changes, 72% showed good results; 93% showed improvement. In knees with stage II changes, 59% showed good results; 81% showed improvement. These preliminary results indicate that dysprosium 165-ferric hydroxide macroaggregate is an effective agent for radiation synovectomy. The low leakage rates observed offer a definite advantage over agents previously used.

  7. Electrochemical formation of hydroxide for enhancing carbon dioxide and acid gas uptake by a solution

    DOEpatents

    Rau, Gregory Hudson

    2014-07-01

    A system for forming metal hydroxide from a metal carbonate utilizes a water electrolysis cell having an acid-producing anode and a hydroxyl-producing cathode immersed in a water solution of sufficient ionic content to allow an electric current to pass between the hydroxyl-producing cathode and the acid-producing anode. A metal carbonate is placed in close proximity to the acid-producing anode. A direct current electrical voltage is provided across the acid-producing anode and the hydroxyl-producing cathode sufficient to generate acid at the acid-producing anode and hydroxyl ions at the hydroxyl-producing cathode. The acid dissolves at least part of the metal carbonate into metal and carbonate ions allowing the metal ions to travel toward the hydroxyl-producing cathode and to combine with the hydroxyl ions to form the metal hydroxide. The carbonate ions travel toward the acid-producing anode and form carbonic acid and/or water and carbon dioxide.

  8. Synthesis and controlled release properties of 2,4-dichlorophenoxy acetate–zinc layered hydroxide nanohybrid

    SciTech Connect

    Bashi, Abbas M.; Hussein, Mohd Zobir; Zainal, Zulkarnain; Tichit, Didier

    2013-07-15

    Direct reaction of ZnO with 2,4-dichlorophenoxyacetic acid (24D) solutions of different concentrations allows obtaining new organic–inorganic nanohybrid materials formed by intercalation of 24D into interlayers of zinc layered hydroxide (ZLH). XRD patterns show a progressive evolution of the structure as 24D concentration increases. The nanohybrid obtained at higher 24D concentration (24D–ZLH(0.4)) reveals a well ordered layered structure with two different basal spacings at 25.2 Å and 24 Å. The FTIR spectrum showing the vibrations bands of the functional groups of 24D and of the ZLH confirms the intercalation. SEM images are in agreement with the structural evolution observed by XRD and reveal the ribbon morphology of the nanohybrids. The release studies of 24D showed a rapid release of 94% for the first 100 min governed by the pseudo-second order kinetic model. - Graphical abstract: The phenomenon indicates that the optical energy gap is enlarged with the increase of molar concentrations in 2,4-dichlorophenoxy acetate anion content into ZnO to create a ZLH–24D nanohybrid. - Highlights: • Nanohybrid was synthesized from 2,4-dichlorophenoxy acetate with-Zinc LHD, using wet chemistry. • Characterized using SEM, TEM, EDX, FTIR, XRD and TGA. • Ribbon-shaped 24D–Zn-layered hydroxide nanoparticles with (003) diffractions of 2.5 nm phase were synthesized.

  9. Synthesis of (cinnamate-zinc layered hydroxide) intercalation compound for sunscreen application

    PubMed Central

    2013-01-01

    Background Zinc layered hydroxide (ZLH) intercalated with cinnamate, an anionic form of cinnamic acid (CA), an efficient UVA and UVB absorber, have been synthesized by direct method using zinc oxide (ZnO) and cinnamic acid as the precursor. Results The resulting obtained intercalation compound, ZCA, showed a basal spacing of 23.9 Å as a result of cinnamate intercalated in a bilayer arrangement between the interlayer spaces of ZLH with estimated percentage loading of cinnamate of about 40.4 % w/w. The UV–vis absorption spectrum of the intercalation compound showed excellent UVA and UVB absorption ability. Retention of cinnamate in ZLH interlayers was tested against media usually came across with sunscreen usage to show low release over an extended period of time. MTT assay of the intercalation compound on human dermal fibroblast (HDF) cells showed cytotoxicity of ZCA to be concentration dependent and is overall less toxic than its precursor, ZnO. Conclusions (Cinnamate-zinc layered hydroxide) intercalation compound is suitable to be used as a safe and effective sunscreen with long UV protection effect. PMID:23383738

  10. Tetramethylammonium hydroxide as a reagent for complex mixture analysis by negative ion electrospray ionization mass spectrometry.

    PubMed

    Lobodin, Vladislav V; Juyal, Priyanka; McKenna, Amy M; Rodgers, Ryan P; Marshall, Alan G

    2013-08-20

    Ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS) enables the direct characterization of complex mixtures without prior fractionation. High mass resolution can distinguish peaks separated by as little as 1.1 mDa), and high mass accuracy enables assignment of elemental compositions in mixtures that contain tens of thousands of individual components (crude oil). Negative electrospray ionization (ESI) is particularly useful for the speciation of the most acidic petroleum components that are implicated in oil production and processing problems. Here, we replace conventional ammonium hydroxide by tetramethylammonium hydroxide (TMAH, a much stronger base, with higher solubility in toluene) to more uniformly deprotonate acidic components of complex mixtures by negative ESI FTICR MS. The detailed compositional analysis of four crude oils (light to heavy, from different geographical locations) reveals that TMAH reagent accesses 1.5-6 times as many elemental compositions, spanning a much wider range of chemical classes than does NH4OH. For example, TMAH reagent produces abundant negative electrosprayed ions from less acidic and neutral species that are in low abundance or absent with NH4OH reagent. More importantly, the increased compositional coverage of TMAH-modified solvent systems maintains, or even surpasses, the compositional information for the most acidic species. The method is not limited to petroleum-derived materials and could be applied to the analysis of dissolved organic matter, coal, lipids, and other naturally occurring compositionally complex organic mixtures. PMID:23919350

  11. Enhanced thermal- and photo-stability of acid yellow 17 by incorporation into layered double hydroxides

    SciTech Connect

    Wang Qian; Feng Yongjun; Feng Junting; Li Dianqing

    2011-06-15

    2,5-dichloro-4-(5-hydroxy-3-methyl-4-(sulphophenylazo) pyrazol-1-yl) benzenesulphonate (DHSB) anions, namely acid yellow 17 anions, have been successfully intercalated into Zn-Al layered double hydroxides (LDH) to produce a novel organic-inorganic pigment by a simple method involving separate nucleation and aging steps (SNAS), and the dye-intercalated LDH was analyzed by various techniques, e.g., XRD, SEM, FT-IR, TG-DTA and ICP. The d-spacing of the prepared LDH is 2.09 nm. Furthermore, the incorporation of the DHSB aims to enhance the thermal- and photo-stability of the guest dye molecule, for example, the less color change after accelerated thermal- and photo-aging test. - Graphical abstract: Acid yellow anions were successfully assembled into ZnAl layered double hydroxides (LDH) to produce a novel organic-inorganic composite pigment by a simple method involving separate nucleation and aging steps (SNAS). Highlights: > Acid yellow 17 was directly intercalated into ZnAl-LDH to form a novel pigment. > The pigment was prepared by a method involving separate nucleation and aging steps. > The intercalation of dye anions enhances its thermal- and photo-stability.

  12. Migration along orthodromic sun compass routes by arctic birds.

    PubMed

    Alerstam, T; Gudmundsson, G A; Green, M; Hedenstrom, A

    2001-01-12

    Flight directions of birds migrating at high geographic and magnetic latitudes can be used to test bird orientation by celestial or geomagnetic compass systems under polar conditions. Migration patterns of arctic shorebirds, revealed by tracking radar studies during an icebreaker expedition along the Northwest Passage in 1999, support predicted sun compass trajectories but cannot be reconciled with orientation along either geographic or magnetic loxodromes (rhumb lines). Sun compass routes are similar to orthodromes (great circle routes) at high latitudes, showing changing geographic courses as the birds traverse longitudes and their internal clock gets out of phase with local time. These routes bring the shorebirds from high arctic Canada to the east coast of North America, from which they make transoceanic flights to South America. The observations are also consistent with a migration link between Siberia and the Beaufort Sea region by way of sun compass routes across the Arctic Ocean. PMID:11209079

  13. Migration along orthodromic sun compass routes by arctic birds.

    PubMed

    Alerstam, T; Gudmundsson, G A; Green, M; Hedenstrom, A

    2001-01-12

    Flight directions of birds migrating at high geographic and magnetic latitudes can be used to test bird orientation by celestial or geomagnetic compass systems under polar conditions. Migration patterns of arctic shorebirds, revealed by tracking radar studies during an icebreaker expedition along the Northwest Passage in 1999, support predicted sun compass trajectories but cannot be reconciled with orientation along either geographic or magnetic loxodromes (rhumb lines). Sun compass routes are similar to orthodromes (great circle routes) at high latitudes, showing changing geographic courses as the birds traverse longitudes and their internal clock gets out of phase with local time. These routes bring the shorebirds from high arctic Canada to the east coast of North America, from which they make transoceanic flights to South America. The observations are also consistent with a migration link between Siberia and the Beaufort Sea region by way of sun compass routes across the Arctic Ocean.

  14. Optimization of UV absorptivity of layered double hydroxide by intercalating organic UV-absorbent molecules.

    PubMed

    Mohsin, Sumaiyah Megat Nabil; Hussein, Mohd Zobir; Sarijo, Siti Halimah; Fakurazi, Sharida; Arulselvan, Palanisamy; Taufiq-Yap, Yun Hin

    2014-08-01

    Intercalation of Zn/Al layered double hydroxide (LDH) with benzophenone 9 (B9), a strong ultraviolet (UV) absorber, had been carried out by two different routes; co-precipitation and ion exchange method. Powder X-ray diffraction (PXRD) patterns of co-precipitated (ZB9C) and ion exchanged product (ZB91) showed basal spacing of 15.9 angstrom and 16.6 angstrom, respectively, as a result of the intercalation of B9 anions into the lamellae spaces of LDH. Intercalation was further confirmed by Fourier transform infrared spectra (FTIR), carbon, hydrogen, nitrogen and sulfur (CHNS) and thermogravimetric and differential thermogravimetric (TGA/DTG) studies. UV-vis absorption properties of the nanocomposite was investigated with diffuse reflectance UV-visible spectrometer and showed broader UV absorption range. Furthermore, stability of sunscreen molecules in LDH interlayer space was tested in deionized water, artificial sea water and skin pH condition to show slow deintercalation and high retention in host. Cytotoxicity study of the synthesized nanocomposites on human dermal fibroblast (HDF) cells shows no significant cytotoxicity after 24 h exposure for test concentrations up to 25 microg/mL. PMID:25016649

  15. Deconstruction of Lignin Model Compounds and Biomass-Derived Lignin using Layered Double Hydroxide Catalysts

    SciTech Connect

    Chmely, S. C.; McKinney, K. A.; Lawrence, K. R.; Sturgeon, M.; Katahira, R.; Beckham, G. T.

    2013-01-01

    Lignin is an underutilized value stream in current biomass conversion technologies because there exist no economic and technically feasible routes for lignin depolymerization and upgrading. Base-catalyzed deconstruction (BCD) has been applied for lignin depolymerization (e.g., the Kraft process) in the pulp and paper industry for more than a century using aqueous-phase media. However, these efforts require treatment to neutralize the resulting streams, which adds significantly to the cost of lignin deconstruction. To circumvent the need for downstream treatment, here we report recent advances in the synthesis of layered double hydroxide and metal oxide catalysts to be applied to the BCD of lignin. These catalysts may prove more cost-effective than liquid-phase, non-recyclable base, and their use obviates downstream processing steps such as neutralization. Synthetic procedures for various transition-metal containing catalysts, detailed kinetics measurements using lignin model compounds, and results of the application of these catalysts to biomass-derived lignin will be presented.

  16. Electrochemical impregnation of nickel hydroxide in porous electrodes

    NASA Technical Reports Server (NTRS)

    Ho, Kuo-Chuan; Jorne, Jacob

    1987-01-01

    The electrochemical impregnation of nickel hydroxide in porous electrode was investigated both experimentally and theoretically. The loading level and plaque expansion were the most important parameters to be considered. The effects of applied current density, stirring, ratio of solution to electrode volume and pH were identified. A novel flow through electrochemical impregnation is proposed in which the electrolyte is forced through the porous nickel plaque. The thickening of the plaque can be reduced while maintaining high loading capacity. A mathematical model is presented which describes the transport of the nitrate, nickel and hydroxyl ions and the consecutive heterogeneous electrochemical reduction of nitrate and the homogeneous precipitation reaction of nickel hydroxide. The distributions of precipitation rate and active material within the porous electrode are obtained. A semiempirical model is also proposed which takes into account the plugging of the pores.

  17. A Case of Recurrent Renal Aluminum Hydroxide Stone

    PubMed Central

    Cakıroglu, Basri; Dogan, Akif Nuri; Tas, Tuncay; Gozukucuk, Ramazan; Uyanik, Bekir Sami

    2014-01-01

    Renal stone disease is characterized by the differences depending on the age, gender, and the geographic location of the patients. Seventy-five percent of the renal stone components is the calcium (Ca). The most common type of the stones is the Ca oxalate stones, while Ca phosphate, uric acid, struvite, and sistine stones are more rarely reported. Other than these types, triamterene, adenosine, silica, indinavir, and ephedrine stones are also reported in the literature as case reports. However, to the best of our knowledge, aluminum hydroxide stones was not reported reported before. Herein we will report a 38-years-old woman with the history of recurrent renal colic disease whose renal stone was determined as aluminum hydroxide stone in type. Aluminum mineral may be considered in the formation of kidney stones as it is widely used in the field of healthcare and cosmetics. PMID:25013740

  18. Microbial susceptibility to calcium hydroxide pastes and their vehicles.

    PubMed

    Gomes, Brenda Paula Figueiredo de Almeida; Ferraz, Caio Cezar Randi; Garrido, Fabio Devora; Rosalen, Pedro Luiz; Zaia, Alexandre Augusto; Teixeira, Fabricio Batista; de Souza-Filho, Francisco José

    2002-11-01

    The aim of this study was to investigate the susceptibility of some microorganisms commonly isolated from root canals to calcium hydroxide in combination with several vehicles by the agar diffusion method. Stainless-steel cylinders were placed on each inoculated agar medium. The test medications and their controls were placed inside the cylinders. The zones of growth inhibition were measured and recorded after the incubation period for each plate, and the results were analyzed statistically. Enterococcus faecalis was most resistant, whereas the anaerobic Porphyromonas endodontalis was more susceptible to all medications, followed by P. gingivalis and Prevotella intermedial intermedia. Ca(OH)2 + CMCP + glycerin showed significantly larger mean zones of inhibition when compared with the other medications. We conclude that anaerobic Gram-negative bacteria are more susceptible to calcium hydroxide pastes than facultative Gram-positive microorganisms. PMID:12470019

  19. Preparation and photoluminescence study of mesoporous indium hydroxide nanorods

    SciTech Connect

    Li, Changyu; Lian, Suoyuan; Liu, Yang; Liu, Shouxin; Kang, Zhenhui

    2010-02-15

    Mesoporous indium hydroxide nanorods were successfully synthesized by a mild one-step one-pot method. The obtained samples were characterized by X-ray diffraction, transmission electron microscopy with selected area electron diffraction, N{sub 2} adsorption, ultraviolet-visible absorption and photoluminescence, respectively. Transmission electron microscopy showed that there were some pores in the samples, which were mainly composed of rod-like shapes with length of 300 nm and diameter of 90 nm. N{sub 2} adsorption/desorption measurements confirmed that the prepared powder was mesoporous with average pore diameter of 3.1 nm. The ultraviolet-visible absorption spectroscopy analysis indicated that the band gap energy of the samples was 5.15 eV. Photoluminescence spectrum showed that there were two strong emissions under ultraviolet light irradiation. The growth mechanism of indium hydroxide nanorods and the role of cetyltrimethyl ammonium bromide were also discussed.

  20. A chlorate candle/lithium hydroxide personal breathing apparatus

    NASA Technical Reports Server (NTRS)

    Martin, F. E.

    1972-01-01

    A portable coal mine rescue and survival equipment is reported that consists of a chlorate candle with a lithium hydroxide carbon-dioxide absorbent for oxygen generation, a breathing bag and tubing to conduct breathing to and from the man. A plastic hood incorporating a mouth piece for communication provides also eye protection and prevents inhalation through the nose. Manned testing of a prototype system demonstrated the feasibility of this closed circuit no-maintenance breathing apparatus that provides for good voice communication.

  1. Mesenchymal stem cells in corneal neovascularization: Comparison of different application routes

    PubMed Central

    Ghazaryan, Emma; Zhang, Yan; He, Yuxi; Liu, Xin; Li, Ying; Xie, Jianan; Su, Guanfang

    2016-01-01

    The purpose of the present study is to investigate the effect of mesenchymal stem cells in corneal neovascularization and wound healing, and to compare the effectiveness of two possible application routes, subconjunctival injection and amniotic membrane transplantation. Chemical injury was induced by application of sodium hydroxide to the rats' corneas. After 7 days, the animals were divided into three groups. Different treatment methods were used for each group as follows: i) Group 1, injection of bone marrow-derived mesenchymal stem cells (BMSCs) under the conjunctiva; ii) group 2, transplantation of amniotic membranes, previously seeded with BMSCs; and iii) group 3, the untreated control group. The eyes were examined using a slit lamp on a weekly basis. After 4 weeks, the animals were sacrificed and corneas were removed for further examination. Corneal flat mounts were made following ink perfusion for improved vessel visualization, image capturing and quantitative evaluation. enzyme-linked immunosorbent assay was performed to detect the levels of vascular endothelial growth factor (VEGF) and matrix metalloproteinase 9 (MMP-9). Reverse transcription-quantitative polymerase chain reaction was used for detection of VEGF-A, MMP-9, Toll-like receptor (TLR)2 and TLR4 gene expression levels. Cryosections were used for histological examination and immunostaining. Statistical analysis (Welch's one-way analysis of variance) demonstrated a significant difference between the groups [P≤0.05, confidence interval (CI) 95%]. The level of injury in group 1 was significantly different from groups 2 and 3. Measurement of the vessel area and VEGF gene expression levels had a similar difference among the groups (P≤0.05, CI 95%), however the differences for TLR2 and TLR4 were not statistically significant. BMSCs were previously transduced with the green fluorescent protein gene by lentivirus to track the movement of the cells following transplantation. The transplanted cells

  2. Mesenchymal stem cells in corneal neovascularization: Comparison of different application routes.

    PubMed

    Ghazaryan, Emma; Zhang, Yan; He, Yuxi; Liu, Xin; Li, Ying; Xie, Jianan; Su, Guanfang

    2016-10-01

    The purpose of the present study is to investigate the effect of mesenchymal stem cells in corneal neovascularization and wound healing, and to compare the effectiveness of two possible application routes, subconjunctival injection and amniotic membrane transplantation. Chemical injury was induced by application of sodium hydroxide to the rats' corneas. After 7 days, the animals were divided into three groups. Different treatment methods were used for each group as follows: i) Group 1, injection of bone marrow‑derived mesenchymal stem cells (BMSCs) under the conjunctiva; ii) group 2, transplantation of amniotic membranes, previously seeded with BMSCs; and iii) group 3, the untreated control group. The eyes were examined using a slit lamp on a weekly basis. After 4 weeks, the animals were sacrificed and corneas were removed for further examination. Corneal flat mounts were made following ink perfusion for improved vessel visualization, image capturing and quantitative evaluation. enzyme‑linked immunosorbent assay was performed to detect the levels of vascular endothelial growth factor (VEGF) and matrix metalloproteinase 9 (MMP‑9). Reverse transcription‑quantitative polymerase chain reaction was used for detection of VEGF‑A, MMP‑9, Toll‑like receptor (TLR)2 and TLR4 gene expression levels. Cryosections were used for histological examination and immunostaining. Statistical analysis (Welch's one‑way analysis of variance) demonstrated a significant difference between the groups [P≤0.05, confidence interval (CI) 95%]. The level of injury in group 1 was significantly different from groups 2 and 3. Measurement of the vessel area and VEGF gene expression levels had a similar difference among the groups (P≤0.05, CI 95%), however the differences for TLR2 and TLR4 were not statistically significant. BMSCs were previously transduced with the green fluorescent protein gene by lentivirus to track the movement of the cells following transplantation

  3. Behaviour of the surface hydroxide groups of exfoliated kaolinite in the gas phase and during water adsorption.

    PubMed

    Táborosi, Attila; Szilágyi, Róbert K

    2016-02-14

    The chemical and physical properties, and thus the reactivity of phylloaluminosilicates can be tailored by intercalation, delamination, and exfoliation processes. In going from the periodic crystalline to the molecular exfoliated phase, surface defects and modifications gain importance as each face of the phylloaluminosilicate comes in direct contact with the external chemical environment. In this work, we extend our earlier studies on the molecular cluster modelling of exfoliated kaolinite sheets by evaluating the positions and orientations of surface hydroxide groups and bridging oxide anions, as the sites of reactivity. The previous focus on the inner chemical environment of a single kaolinite layer is shifted to the surface exposed octahedral aluminium-hydroxide and tetrahedral silicon-oxide sheets. The combination of semi-empirical, ab initio wave function, and density functional calculations unanimously support the amphoteric nature of the surface hydroxide groups with respect to H-bonding donor/acceptor capabilities. To a lesser extent, we observe the same for the bridging oxide anions. This is in contrast to the crystalline phase, which manifests only donor orientation for maintaining an inter-layer H-bond network. These results suggest that both electrophilic and nucleophilic characteristics of the octahedral and tetrahedral sheets need to be considered during intercalation and concomitant exfoliation of the kaolinite sheets.

  4. Behaviour of the surface hydroxide groups of exfoliated kaolinite in the gas phase and during water adsorption.

    PubMed

    Táborosi, Attila; Szilágyi, Róbert K

    2016-02-14

    The chemical and physical properties, and thus the reactivity of phylloaluminosilicates can be tailored by intercalation, delamination, and exfoliation processes. In going from the periodic crystalline to the molecular exfoliated phase, surface defects and modifications gain importance as each face of the phylloaluminosilicate comes in direct contact with the external chemical environment. In this work, we extend our earlier studies on the molecular cluster modelling of exfoliated kaolinite sheets by evaluating the positions and orientations of surface hydroxide groups and bridging oxide anions, as the sites of reactivity. The previous focus on the inner chemical environment of a single kaolinite layer is shifted to the surface exposed octahedral aluminium-hydroxide and tetrahedral silicon-oxide sheets. The combination of semi-empirical, ab initio wave function, and density functional calculations unanimously support the amphoteric nature of the surface hydroxide groups with respect to H-bonding donor/acceptor capabilities. To a lesser extent, we observe the same for the bridging oxide anions. This is in contrast to the crystalline phase, which manifests only donor orientation for maintaining an inter-layer H-bond network. These results suggest that both electrophilic and nucleophilic characteristics of the octahedral and tetrahedral sheets need to be considered during intercalation and concomitant exfoliation of the kaolinite sheets. PMID:26705545

  5. Ion chromatographic determination of hydroxide ion on monolithic reversed-phase silica gel columns coated with nonionic and cationic surfactants.

    PubMed

    Xu, Qun; Mori, Masanobu; Tanaka, Kazuhiko; Ikedo, Mikaru; Hu, Wenzhi; Haddad, Paul R

    2004-07-01

    The determination of hydroxide by ion chromatography (IC) is demonstrated using a monolithic octadecylsilyl (ODS)-silica gel column coated first with a nonionic surfactant (polyoxyethylene (POE)) and then with a cationic surfactant (cetyltrimethylammonium bromide (CTAB)). This stationary phase, when used in conjunction with a 10 mmol/l sodium sulfate eluent at pH 8.2, was found to be suitable for the rapid and efficient separation of hydroxide from some other anions, based on a conventional ion-exchange mechanism. The peak directions and detection responses for these ions were in agreement with their known limiting equivalent ionic conductance values. Under these conditions, a linear calibration plot was obtained for hydroxide ion over the range 16 micromol/l to 15 mmol/l, and the detection limit determined at a signal-to-noise ratio of 3 was 6.4 micromol/l. The double-coated stationary phase described above was shown to be superior to a single coating of cetyltrimethylammonium bromide alone, in terms of separation efficiency and stability of the stationary phase. A range of samples comprising solutions of some strong and weak bases was analyzed by the proposed method and the results obtained were in good agreement with those obtained by conventional potentiometric pH measurement.

  6. Toxicity and Metabolism of Layered Double Hydroxide Intercalated with Levodopa in a Parkinson’s Disease Model

    PubMed Central

    Kura, Aminu Umar; Ain, Nooraini Mohd; Hussein, Mohd Zobir; Fakurazi, Sharida; Hussein-Al-Ali, Samer Hasan

    2014-01-01

    Layered hydroxide nanoparticles are generally biocompatible, and less toxic than most inorganic nanoparticles, making them an acceptable alternative drug delivery system. Due to growing concern over animal welfare and the expense of in vivo experiments both the public and the government are interested to find alternatives to animal testing. The toxicity potential of zinc aluminum layered hydroxide (ZAL) nanocomposite containing anti-Parkinsonian agent may be determined using a PC 12 cell model. ZAL nanocomposite demonstrated a decreased cytotoxic effect when compared to levodopa on PC12 cells with more than 80% cell viability at 100 μg/mL compared to less than 20% cell viability in a direct levodopa exposure. Neither levodopa-loaded nanocomposite nor the un-intercalated nanocomposite disturbed the cytoskeletal structure of the neurogenic cells at their IC50 concentration. Levodopa metabolite (HVA) released from the nanocomposite demonstrated the slow sustained and controlled release character of layered hydroxide nanoparticles unlike the burst uptake and release system shown with pure levodopa treatment. PMID:24722565

  7. Synthesis of high capacity cathodes for lithium-ion batteries by morphology-tailored hydroxide co-precipitation

    NASA Astrophysics Data System (ADS)

    Wang, Dapeng; Belharouak, Ilias; Ortega, Luis H.; Zhang, Xiaofeng; Xu, Rui; Zhou, Dehua; Zhou, Guangwen; Amine, Khalil

    2015-01-01

    Nickel manganese hydroxide co-precipitation inside a continuous stirred tank reactor was studied with sodium hydroxide and ammonium hydroxide as the precipitation agents. The ammonium hydroxide concentration had an effect on the primary and secondary particle evolution. The two-step precipitation mechanism proposed earlier was experimentally confirmed. In cell tests, Li- and Mn-rich composite cathode materials based on the hydroxide precursors demonstrated good electrochemical performance in terms of cycle life over a wide range of lithium content.

  8. Landmarks as beacons and associative cues: their role in route learning.

    PubMed

    Waller, David; Lippa, Yvonne

    2007-07-01

    Relatively little is known about how people use the landmarks in their environment to learn routes. Landmarks are commonly regarded as associative cues--stimuli that enable recall of directional responses that lead closer to the navigator's goal. We contrast the function of landmark as associative cue with that of a beacon-a landmark near enough to a goal that moving toward it leads the navigator closer to his or her goal. In five experiments, participants learned a route through a simple desktop virtual environment. In the first three experiments, routes were learned better when their landmarks served as beacons than as associative cues. Two additional experiments showed that the acquired route knowledge depends on the function that landmarks serve during learning. Beacon-based route knowledge is less enduring and relatively less likely to involve knowledge of directions in the environment than is the route knowledge formed from landmarks that serve as associative cues.

  9. Central East Pacific Flight Routing

    NASA Technical Reports Server (NTRS)

    Grabbe, Shon; Sridhar, Banavar; Kopardekar, Parimal; Cheng, Nadia

    2006-01-01

    With the introduction of the Federal Aviation Administration s Advanced Technology and Oceanic Procedures system at the Oakland Oceanic Center, a level of automation now exists in the oceanic environment to potentially begin accommodating increased user preferred routing requests. This paper presents the results of an initial feasibility assessment which examines the potential benefits of transitioning from the fixed Central East Pacific routes to user preferred routes. As a surrogate for the actual user-provided routing requests, a minimum-travel-time, wind-optimal dynamic programming algorithm was developed and utilized in this paper. After first describing the characteristics (e.g., origin airport, destination airport, vertical distribution and temporal distribution) of the westbound flights utilizing the Central East Pacific routes on Dec. 14-16 and 19-20, the results of both a flight-plan-based simulation and a wind-optimal-based simulation are presented. Whereas the lateral and longitudinal distribution of the aircraft trajectories in these two simulations varied dramatically, the number of simulated first-loss-of-separation events remained relatively constant. One area of concern that was uncovered in this initial analysis was a potential workload issue associated with the redistribution of traffic in the oceanic sectors due to thc prevailing wind patterns.

  10. [Pathway of aqueous ferric hydroxide catalyzed ozone decomposition and ozonation of trace nitrobenzene].

    PubMed

    Ma, Jun; Zhang, Tao; Chen, Zhong-lin; Sui, Ming-hao; Li, Xue-yan

    2005-03-01

    In this paper, the decomposition rate of ozone in water was measured over GAC and ferric hydroxide/GAC (FeOOH/GAC) catalyst and the mechanism of ozone catalytic decomposition was discussed. The catalytic ozonation activity of trace nitrobenzene in water was determined on several metal oxides and correlated with their surface density of hydroxyl groups and pHzpc,(pH of zero point of charge). The results show that: 1) The pseudo-first order rate of ozone decomposition increased by 68 and 108 percent for GAC and FeOOH/GAC catalysts respectively; 2) When t-butanol was added, the rate constant decreased by 9 % for GAC and 20% for FeOOH/GAC; 3) There was no direct correlation between surface density of hydroxyl groups and the activity of catalytic ozonation of nitrobenzene; 4) The oxide surface at nearly zero charged point was favorable for the catalytic ozonation of nitrobenzene.

  11. Metallic Nickel Hydroxide Nanosheets Give Superior Electrocatalytic Oxidation of Urea for Fuel Cells.

    PubMed

    Zhu, Xiaojiao; Dou, Xinyu; Dai, Jun; An, Xingda; Guo, Yuqiao; Zhang, Lidong; Tao, Shi; Zhao, Jiyin; Chu, Wangsheng; Zeng, Xiao Cheng; Wu, Changzheng; Xie, Yi

    2016-09-26

    The direct urea fuel cell (DUFC) is an important but challenging renewable energy production technology, it offers great promise for energy-sustainable developments and mitigating water contamination. However, DUFCs still suffer from the sluggish kinetics of the urea oxidation reaction (UOR) owing to a 6 e(-) transfer process, which poses a severe hindrance to their practical use. Herein, taking β-Ni(OH)2 nanosheets as the proof-of-concept study, we demonstrated a surface-chemistry strategy to achieve metallic Ni(OH)2 nanosheets by engineering their electronic structure, representing a first metallic configuration of transition-metal hydroxides. Surface sulfur incorporation successfully brings synergetic effects of more exposed active sites, good wetting behavior, and effective electron transport, giving rise to greatly enhanced performance for UOR. Metallic nanosheets exhibited a much higher current density, smaller onset potential and stronger durability. PMID:27572334

  12. Nanostructuring of nickel hydroxide via a template solution approach for efficient electrochemical devices.

    PubMed

    Guo, Li; Ren, Yi; Liu, Junyi; Chiam, Sing Yang; Chim, Wai Kin

    2014-07-01

    Nanostructuring is a key approach in enhancing the performance of electrochemical devices. In this work, nanostructuring is achieved by the electrodeposition of nickel hydroxide nanowire arrays, with both open-ended and close-ended structures, through anodized aluminium oxide (AAO) templates that are directly fabricated on indium tin oxide/glass substrates. The open-ended and close-ended nanostructures are compared together with identically fabricated thin films to show the effects of nanostructuring. Open-ended nanowire arrays demonstrated the best electrochemical activity with superior transmittance modulation and faster activation, while the thin film showed the worst performance. In comparing with the close-ended structures, enhanced performance is observed for the open-ended structures despite the use of less material for the latter. This demonstrates that in designing nanostructures or porous materials, it is important for the porosity to have both interconnectivity and exposure to the electrolyte in electrochemical reactions. PMID:24634166

  13. Metallic Nickel Hydroxide Nanosheets Give Superior Electrocatalytic Oxidation of Urea for Fuel Cells.

    PubMed

    Zhu, Xiaojiao; Dou, Xinyu; Dai, Jun; An, Xingda; Guo, Yuqiao; Zhang, Lidong; Tao, Shi; Zhao, Jiyin; Chu, Wangsheng; Zeng, Xiao Cheng; Wu, Changzheng; Xie, Yi

    2016-09-26

    The direct urea fuel cell (DUFC) is an important but challenging renewable energy production technology, it offers great promise for energy-sustainable developments and mitigating water contamination. However, DUFCs still suffer from the sluggish kinetics of the urea oxidation reaction (UOR) owing to a 6 e(-) transfer process, which poses a severe hindrance to their practical use. Herein, taking β-Ni(OH)2 nanosheets as the proof-of-concept study, we demonstrated a surface-chemistry strategy to achieve metallic Ni(OH)2 nanosheets by engineering their electronic structure, representing a first metallic configuration of transition-metal hydroxides. Surface sulfur incorporation successfully brings synergetic effects of more exposed active sites, good wetting behavior, and effective electron transport, giving rise to greatly enhanced performance for UOR. Metallic nanosheets exhibited a much higher current density, smaller onset potential and stronger durability.

  14. Layered double hydroxides toward electrochemical energy storage and conversion: design, synthesis and applications.

    PubMed

    Shao, Mingfei; Zhang, Ruikang; Li, Zhenhua; Wei, Min; Evans, David G; Duan, Xue

    2015-11-14

    Two-dimensional (2D) materials have attracted increasing interest in electrochemical energy storage and conversion. As typical 2D materials, layered double hydroxides (LDHs) display large potential in this area due to the facile tunability of their composition, structure and morphology. Various preparation strategies, including in situ growth, electrodeposition and layer-by-layer (LBL) assembly, have been developed to directly modify electrodes by using LDH materials. Moreover, several composite materials based on LDHs and conductive matrices have also been rationally designed and employed in supercapacitors, batteries and electrocatalysis with largely enhanced performances. This feature article summarizes the latest developments in the design, preparation and evaluation of LDH materials toward electrochemical energy storage and conversion.

  15. FAD C(4a)-hydroxide stabilized in a naturally fused styrene monooxygenase.

    PubMed

    Tischler, Dirk; Schlömann, Michael; van Berkel, Willem J H; Gassner, George T

    2013-11-29

    StyA2B represents a new class of styrene monooxygenases that integrates flavin-reductase and styrene-epoxidase activities into a single polypeptide. This naturally-occurring fusion protein offers new avenues for studying and engineering biotechnologically relevant enantioselective biochemical epoxidation reactions. Stopped-flow kinetic studies of StyA2B reported here identify reaction intermediates similar to those reported for the separate reductase and epoxidase components of related two-component systems. Our studies identify substrate epoxidation and elimination of water from the FAD C(4a)-hydroxide as rate-limiting steps in the styrene epoxidation reaction. Efforts directed at accelerating these reaction steps are expected to greatly increase catalytic efficiency and the value of StyA2B as biocatalyst.

  16. Routes to embodiment

    PubMed Central

    Körner, Anita; Topolinski, Sascha; Strack, Fritz

    2015-01-01

    Research on embodiment is rich in impressive demonstrations but somewhat poor in comprehensive explanations. Although some moderators and driving mechanisms have been identified, a comprehensive conceptual account of how bodily states or dynamics influence behavior is still missing. Here, we attempt to integrate current knowledge by describing three basic psychological mechanisms: direct state induction, which influences how humans feel or process information, unmediated by any other cognitive mechanism; modal priming, which changes the accessibility of concepts associated with a bodily state; sensorimotor simulation, which affects the ease with which congruent and incongruent actions are performed. We argue that the joint impact of these mechanisms can account for most existing embodiment effects. Additionally, we summarize empirical tests for distinguishing these mechanisms and suggest a guideline for future research about the mechanisms underlying embodiment effects. PMID:26191033

  17. Smart aircraft routing - a possibility for mitigation?

    NASA Astrophysics Data System (ADS)

    Mannstein, H.; Gierens, K.; Graf, K.; Waibel, A.; Meilinger, S.; Seifert, A.; Köhler, C.

    2009-12-01

    Air traffic affects the energy balance of the earth in various ways. Emission of CO2 with atmospheric residence times measured in decades contributes to the greenhouse effect as well as emission of nitrous oxides, with their impact on ozone and methane chemistry. Soot has a direct effect on the net radiation and, much more important, is involved in the production of contrails and the triggering of contrail cirrus, which can be visible for several hours. These artificial clouds are initiated when flying in sufficiently cold and moist air. In total, their net radiative forcing is of the same order of magnitude as the forcing by the emitted CO2. The impact of contrail cirrus on net radiation results from the conversion of ambient moisture in ice super-saturated regions into ice crystals and depends strongly on the conditions of the ambient radiation field. It ranges from a warming at night or over bright low clouds to cooling during daytime over dark surfaces like the ocean. For the time being these effects are not at all taken into consideration in aircraft routing: the production of contrails and contrail cirrus happens by chance. The dependency of the radiative forcing by contrail cirrus clouds on the weather conditions opens the possibility for mitigation: Avoiding warming (and perhaps also producing cooling) contrails and contrail cirrus by changes of the flight routes has the potential to reduce the man-made imbalance in radiative forcing. As contrails are produced only in 10%- 20% of the flown distances and only the warming contrails should be avoided, the impact on the traffic system is likely to be limited. The basic idea of the project ’Environmentally compatible flight route optimisation’, funded by the German Ministry for Research and Education is, to predict the time integrated radiative forcing of a potential contrail cirrus based on the information given by a weather forecast model. This information is used in relation to total forcing of the

  18. Smart aircraft routing - a possibility for mitigation?

    NASA Astrophysics Data System (ADS)

    Mannstein, H.; Gierens, K.; Waibel, A.; Meilinger, S.; Seifert, A.; Köhler, C.; Kühne, H.

    2009-04-01

    Air traffic affects the energy balance of the earth in various ways. Emission of CO2 with atmospheric residence times measured in decades contributes to the greenhouse effect as well as emission of nitrous oxides, with their impact on ozone and methane chemistry. Soot has a direct effect on the net radiation and, much more important, is involved the production of contrails and the triggering of contrail cirrus, which can be visible for several hours. These artificial clouds are initiated when flying in sufficiently cold and moist air. In total their net radiative forcing is of the same order of magnitude as the forcing by the emitted CO2. The impact of contrail cirrus on net radiation results from the conversion of ambient moisture in ice super-saturated regions into ice crystals and depends strongly on the conditions of the ambient radiation field. It ranges from a warming at night or over bright low clouds to cooling during daytime over dark surfaces like the ocean. For the time being these effects are not at all taken into consideration in aircraft routing: the production of contrails and contrail cirrus happens by chance. in. The dependency of the radiative forcing by contrail cirrus clouds on the weather conditions opens the possibility for a soft version of geo-engineering: Avoiding warming (and perhaps also producing cooling) contrails and contrail cirrus by small changes of the flight routes has the potential to reduce the man-made imbalance in radiative forcing by a few percent - not much compared to other geo-engineering strategies, but without any adverse consequences. With the exception of a small amount of additional fuel usage no other substances have to be brought into the atmosphere. As contrails are produced only in 10%-20% of the flown distances and only the warming contrails should be avoided, the impact on the traffic system is limited. The basic idea of the project 'Environmentally compatible flight route optimisation', funded by the German

  19. Evaluation of calcium ion release and change in pH on combining calcium hydroxide with different vehicles

    PubMed Central

    Grover, Charu; Shetty, Neeta

    2014-01-01

    Introduction: Intracanal medicaments have traditionally been used in endodontics to disinfect root canals between appointments. Calcium hydroxide is widely used as an intracanal medicament for disinfection and to promote periapical healing. It is stable for long periods, harmless to the body, and bactericidal in a limited area. The efficacy of calcium hydroxide as a disinfectant is dependent on the availability of the hydroxyl ions in the solution that depends on the vehicle in which the calcium hydroxide is carried. In general, three types of vehicles are used: Aqueous, viscous or oily. Some in vitro studies have shown that the type of vehicle has a direct relationship with the concentration and the velocity of ionic liberation as well as with the antibacterial action when the paste is carried into a contaminated area. Aim of the Study: To evaluate the calcium ion release and measure the change in pH of the environment that occurred when calcium hydroxide was combined with different vehicles (distilled water, propylene glycol, calcium hydroxide containing gutta-percha points and chitosan) over different time periods. Materials and Methods: Forty single rooted mandibular first premolar teeth were decoronated for this study. Working length was established and the root canals were enlarged and irrigation accomplished with 2 ml of NaOCl solution after every file. The teeth were then randomly divided into four groups. The canals were then packed with different preparations of calcium hydroxide using the following vehicles-distilled water, propylene glycol, gutta-percha points and chitosan. Calcium ion release in different groups was analyzed using an ultraviolet spectrophotometer at 220 nm. The change in pH of was determined using a pH meter. Results were statistically evaluated using one-way ANOVA test. Result: For calcium ion release, Group 2 showed cumulative drug release of 81.97% at the end of 15 days, whereas Group 1, 3 and 4 showed a release of 99.53, 17.98, 74

  20. Route Flap Damping Made Usable

    NASA Astrophysics Data System (ADS)

    Pelsser, Cristel; Maennel, Olaf; Mohapatra, Pradosh; Bush, Randy; Patel, Keyur

    The Border Gateway Protocol (BGP), the de facto inter-domain routing protocol of the Internet, is known to be noisy. The protocol has two main mechanisms to ameliorate this, MinRouteAdvertisementInterval (MRAI), and Route Flap Damping (RFD). MRAI deals with very short bursts on the order of a few to 30 seconds. RFD deals with longer bursts, minutes to hours. Unfortunately, RFD was found to severely penalize sites for being well-connected because topological richness amplifies the number of update messages exchanged. So most operators have disabled it. Through measurement, this paper explores the avenue of absolutely minimal change to code, and shows that a few RFD algorithmic constants and limits can be trivially modified, with the result being damping a non-trivial amount of long term churn without penalizing well-behaved prefixes' normal convergence process.

  1. Route following and the pigeon's familiar area map.

    PubMed

    Guilford, Tim; Biro, Dora

    2014-01-15

    Homing pigeons (Columba livia) have been the central model of avian navigation research for many decades, but only more recently has research extended into understanding their mechanisms of orientation in the familiar area. The discovery (facilitated by GPS tracking) that pigeons gradually acquire with experience individually idiosyncratic routes home to which they remain faithful on repeated releases, even if displaced off-route, has helped uncover the fundamental role of familiar visual landmarks in the avian familiar area map. We evaluate the robustness and generality of the route-following phenomenon by examining extant studies in depth, including the single published counter-example, providing a detailed comparison of route efficiencies, flight corridor widths and fidelity. We combine this analysis with a review of inferences that can be drawn from other experimental approaches to understanding the nature of familiar area orientation in pigeons, including experiments on landmark recognition, and response to clock-shift, to build the first detailed picture of how bird orientation develops with experience of the familiar area. We articulate alternative hypotheses for how guidance might be controlled during route following, concluding that although much remains unknown, the details of route following strongly support a pilotage interpretation. Predictable patterns of efficiency increase, but limited to the local route, typical corridor widths of 100-200 m, high-fidelity pinch-points on route, attraction to landscape edges, and a robustness to clock-shift procedures, all demonstrate that birds can associatively acquire a map of their familiar area guided (at least partially) by direct visual control from memorised local landscape features.

  2. Systems for the Intermodal Routing of Spent Nuclear Fuel

    SciTech Connect

    Peterson, Steven K; Liu, Cheng

    2015-01-01

    prioritization constraints and modifiers to determine route selection. The limitations of the current model and future directions for development are discussed, including the current state of information on possible intermodal transfer locations for spent fuel.

  3. Routing Algorithm Exploits Spatial Relations

    NASA Technical Reports Server (NTRS)

    Okino, Clayton; Jennings, Esther

    2004-01-01

    A recently developed routing algorithm for broadcasting in an ad hoc wireless communication network takes account of, and exploits, the spatial relationships among the locations of nodes, in addition to transmission power levels and distances between the nodes. In contrast, most prior algorithms for discovering routes through ad hoc networks rely heavily on transmission power levels and utilize limited graph-topology techniques that do not involve consideration of the aforesaid spatial relationships. The present algorithm extracts the relevant spatial-relationship information by use of a construct denoted the relative-neighborhood graph (RNG).

  4. Electrosynthesis and stabilization of α-cobalt hydroxide in the presence of trivalent cations

    NASA Astrophysics Data System (ADS)

    Dixit, Mridula; Vishnu Kamath, P.

    Layered double hydroxides (LDHs) of cobalt with aluminium and chromium, isostructural with α-cobalt(II) hydroxide, are electrosynthesized. This paves the way for their possible impregnation into porous metal plaques for ready use as electrodes in alkaline secondary cells. Unlike pure cobalt hydroxide, the LDHs of cobalt are not amphoteric and retain their α-like structure in strong alkali, even after prolonged ageing. In addition, they exhibit electrochemical activity as shown by cyclic voltammetric studies.

  5. Method of treating inflammatory diseases using a radiolabeled ferric hydroxide calloid

    DOEpatents

    Atcher, Robert W.; Hines, John J.

    1992-01-01

    A ferric hydroxide colloid having an alpha-emitting radionuclide essentially on the outer surfaces and a method of forming same. The method includes oxidizing a ferrous hydroxide to ferric hydroxide in the presence of a preselected radionuclide to form a colloid having the radionuclide on the outer surface thereof, and thereafter washing the colloid, and suspending the washed colloid in a suitable solution. The labelled colloid is useful in cancer therapy and for the treatment of inflamed joints.

  6. Effects of salinity and humic acid on the sorption of Hg on Fe and Mn hydroxides.

    PubMed

    Liang, Peng; Li, Yi-Chun; Zhang, Chan; Wu, Sheng-Chun; Cui, Hao-Jie; Yu, Shen; Wong, Ming H

    2013-01-15

    The objective of this study was to investigate the influence of humic acid (HA) and salinity on adsorption of Hg on the amorphous and crystalline of iron and manganese hydroxides. The results show that the adsorption of Hg(2+) on Fe and Mn hydroxides was inhibited in marine system due to the formation of stable, nonsorbing aqueous HgCl(2) complexes in solution. Moreover, Cl(-) inhibited the Hg(2+) adsorption more severely on amorphous than crystalline hydroxides. The addition of HA inhibited Hg(2+) adsorption on Fe and Mn hydroxides in freshwater system might be attributed to the competition between Hg(2+) and HA on adsorption to Fe and Mn hydroxides. In contrast, the addition of HA promoted Hg(2+) adsorption on Fe and Mn hydroxides in the marine system, which might be due to the addition of humic acid resulted in the reaction between Cl(-) and HA, and therefore the reducing of Cl(-) promoted more Hg(2+) on Fe and Mn hydroxides. In addition, the influence of HA on Hg(2+) adsorption on Fe and Mn hydroxides are more visible for crystalline than amorphous hydroxides.

  7. Sorption of Np (V) by U (VI) hydroxide solids

    SciTech Connect

    Wruck, D A; Brachmann, A; Sylwester, E; Allen, C E A

    1999-09-20

    The distribution of {sup 237}Np(V) between aqueous NaHCO{sub 3} solutions and U(VI) hydroxide solids was investigated. Experiments were initiated by addition of U solids to Np solutions and by coprecipitation of U and Np. Analysis by U L{sub III} extended X-ray absorption fine structure (EXAFS) spectroscopy and infrared absorption spectroscopy indicated the solid phase was synthetic schoepite. Equilibrium Np distribution coefficients were 5-44 mL/g in the pH range 6-8. The results are consistent with adsorption of Np by the solids and provide no evidence of Np incorporation in the bulk solid.

  8. Sodium hydroxide anodization of Ti-Al-4V adherends

    NASA Technical Reports Server (NTRS)

    Filbey, Jennifer A.; Wightman, J. P.; Progar, D. J.

    1987-01-01

    The use of sodium hydroxide anodization (SHA) for Ti-6Al-4V adherends is examined. The SHA surface is evaluated using SEM, X-ray photoelectron spectroscopy, and Auger electron spectroscopy. The SHA procedures of Kennedy et al. (1983) were employed in this experiment. The photomicrographs of the SHA (sandblasted) and PSHA (sandblasted and pickled) oxide surface reveal that the two surfaces differ. The PSHA is patchy and similar to a chromic acid anodization surface and the porosity of the PSHA is more uniform than the SHA surface. The compositions of the surfaces are studied. It is noted that SHA is an effective pretreatment for Ti-6Al-4V adherends.

  9. Bonding by Hydroxide-Catalyzed Hydration and Dehydration

    NASA Technical Reports Server (NTRS)

    Gwo, Dz-Hung

    2008-01-01

    A simple, inexpensive method for bonding solid objects exploits hydroxide-catalyzed hydration and dehydration to form silicate-like networks in thin surface and interfacial layers between the objects. The method can be practiced at room temperature or over a wide range of temperatures. The method was developed especially to enable the formation of precise, reliable bonds between precise optical components. The bonds thus formed exhibit the precision and transparency of bonds formed by the conventional optical-contact method and the strength and reliability of high-temperature frit bonds. The method also lends itself to numerous non-optical applications in which there are requirements for precise bonds and/or requirements for bonds, whether precise or imprecise, that can reliably withstand severe environmental conditions. Categories of such non-optical applications include forming composite materials, coating substrates, forming laminate structures, and preparing objects of defined geometry and composition. The method is applicable to materials that either (1) can form silicate-like networks in the sense that they have silicate-like molecular structures that are extensible into silicate-like networks or (2) can be chemically linked to silicate-like networks by means of hydroxide-catalyzed hydration and dehydration. When hydrated, a material of either type features surface hydroxyl (-OH) groups. In this method, a silicate-like network that bonds two substrates can be formed either by a bonding material alone or by the bonding material together with material from either or both of the substrates. Typically, an aqueous hydroxide bonding solution is dispensed and allowed to flow between the mating surfaces by capillary action. If the surface figures of the substrates do not match precisely, bonding could be improved by including a filling material in the bonding solution. Preferably, the filling material should include at least one ingredient that can be hydrated to

  10. Alzheimer's amyloid-beta rescues yeast from hydroxide toxicity.

    PubMed

    Dubey, Ashok K; Bharadwaj, Prashant R; Varghese, Joseph N; Macreadie, Ian G

    2009-01-01

    Amyloid-beta(Abeta42), which is known to be toxic to neuronal cells, protects yeast cells from severe sodium hydroxide toxicity. More than 85% cell death was caused by treatment with 1 mM NaOH and approximately 95% was observed at a 2 mM concentration. However, greater than 55% cells survived the treatment in the presence of Abeta42. A strong protective effect of the peptide was also evident from the differential staining of the treated culture with propidium iodide.

  11. Iron oxide hydroxide nanoflower assisted removal of arsenic from water

    SciTech Connect

    Raul, Prasanta Kumar; Devi, Rashmi Rekha; Umlong, Iohborlang M.; Thakur, Ashim Jyoti; Banerjee, Saumen; Veer, Vijay

    2014-01-01

    Graphical abstract: Non-magnetic polycrystalline iron oxide hydroxide nanoparticle with flower like morphology is found to play as an effective adsorbent media to remove As(III) from 300 μg L{sup −1} to less than 10 μg L{sup −1} from drinking water over wide range of pH. TEM image clearly reveals that the nanoparticle looks flower like morphology with average particle size less than 20 nm. The maximum sorption capacity of the sorbent is found to be 475 μg g{sup −1} for arsenic at room temperature and the data fitted to different isotherm models indicate the heterogeneity of the adsorbent surface. The material can be regenerated up to 70% using dilute hydrochloric acid and it would be utilized for de-arsenification purposes. - Highlights: • The work includes synthesis of iron oxide hydroxide nanoflower and its applicability for the removal of arsenic from water. • The nanoparticle was characterized using modern instrumental methods like FESEM, TEM, BET, XRD, etc. • The maximum sorption capacity of the sorbent is found to be 475 μg g{sup −1} for arsenic at room temperature. • The sorption is multilayered on the heterogeneous surface of the nano adsorbent. • The mechanism of arsenic removal of IOH nanoflower follows both adsorption and ion-exchange. - Abstract: Non-magnetic polycrystalline iron oxide hydroxide nanoparticle with flower like morphology is found to play as an effective adsorbent media to remove As(III) from 300 μg L{sup −1} to less than 10 μg L{sup −1} from drinking water over wide range of pH. The nanoparticle was characterized by X-ray powder diffraction analysis (XRD), BET surface area, FTIR, FESEM and TEM images. TEM image clearly reveals flower like morphology with average particle size less than 20 nm. The nanoflower morphology is also supported by FESEM images. The maximum sorption capacity of the sorbent is found to be 475 μg g{sup −1} for arsenic and the data fitted to different isotherm models indicate the

  12. A tool for debugging internet multicast routing

    SciTech Connect

    Agarwal, D.; Floyd, S.

    1994-03-01

    In this paper the authors describe a debugging tool that is an effective means of analyzing problems with multicast packet routing in a network. Multicast packet routing is a source-driven distributed calculation performed by the routers in a multicast network. The routes taken by multicast packets are difficult to predict manually due to the large number of variables that must be considered. The multicast route debugging tool allows off-line investigation of the route taken by a multicast packet and the effects of network modifications on that route. The tool has already proved useful in debugging the problems that have occurred in the experimental Internet Multicast Backbone. The multicast route debugging tool currently predicts multicast routes of packets using the distance-vector truncated-broadcast algorithm implemented for Internet multicast traffic. They will be upgrading the tool to allow the user to choose other multicast routing algorithms.

  13. Roots/Routes: Part I

    ERIC Educational Resources Information Center

    Swanson, Dalene M.

    2009-01-01

    This narrative and poetic rendering acts as an articulation of a journey of many routes. It is a storying of critical research issues and events as performances of lived experience. It is a metissage of hybrid, but interrelated, themes that find cohesion through fragmentation and coalescence, severance, and regrowth. These themes are invoked by…

  14. Judaism and the Silk Route.

    ERIC Educational Resources Information Center

    Foltz, Richard

    1998-01-01

    Demonstrates that the Judeans traveled along the Ancient Silk Route. Discusses the Iranian influence on the formation of Jewish religious ideas. Considers the development of Jewish trade networks, focusing on the Radanites (Jewish traders), the Jewish presence in the Far East, and the survival of Judaism in central Asia. (CMK)

  15. Genetic algorithms for route discovery.

    PubMed

    Gelenbe, Erol; Liu, Peixiang; Lainé, Jeremy

    2006-12-01

    Packet routing in networks requires knowledge about available paths, which can be either acquired dynamically while the traffic is being forwarded, or statically (in advance) based on prior information of a network's topology. This paper describes an experimental investigation of path discovery using genetic algorithms (GAs). We start with the quality-of-service (QoS)-driven routing protocol called "cognitive packet network" (CPN), which uses smart packets (SPs) to dynamically select routes in a distributed autonomic manner based on a user's QoS requirements. We extend it by introducing a GA at the source routers, which modifies and filters the paths discovered by the CPN. The GA can combine the paths that were previously discovered to create new untested but valid source-to-destination paths, which are then selected on the basis of their "fitness." We present an implementation of this approach, where the GA runs in background mode so as not to overload the ingress routers. Measurements conducted on a network test bed indicate that when the background-traffic load of the network is light to medium, the GA can result in improved QoS. When the background-traffic load is high, it appears that the use of the GA may be detrimental to the QoS experienced by users as compared to CPN routing because the GA uses less timely state information in its decision making.

  16. Genetic algorithms for route discovery.

    PubMed

    Gelenbe, Erol; Liu, Peixiang; Lainé, Jeremy

    2006-12-01

    Packet routing in networks requires knowledge about available paths, which can be either acquired dynamically while the traffic is being forwarded, or statically (in advance) based on prior information of a network's topology. This paper describes an experimental investigation of path discovery using genetic algorithms (GAs). We start with the quality-of-service (QoS)-driven routing protocol called "cognitive packet network" (CPN), which uses smart packets (SPs) to dynamically select routes in a distributed autonomic manner based on a user's QoS requirements. We extend it by introducing a GA at the source routers, which modifies and filters the paths discovered by the CPN. The GA can combine the paths that were previously discovered to create new untested but valid source-to-destination paths, which are then selected on the basis of their "fitness." We present an implementation of this approach, where the GA runs in background mode so as not to overload the ingress routers. Measurements conducted on a network test bed indicate that when the background-traffic load of the network is light to medium, the GA can result in improved QoS. When the background-traffic load is high, it appears that the use of the GA may be detrimental to the QoS experienced by users as compared to CPN routing because the GA uses less timely state information in its decision making. PMID:17186801

  17. How to choose the route.

    PubMed

    Grecu, Irina

    2013-01-01

    Choosing the route for nutrition support delivery is one of the main steps in the algorithm of providing successful nutrition to the critically ill, but it is certainly not an easy process. The rationale should be guided not only by principles like physiology and benefit versus harm, but also by individual patient factors like feasibility, contraindications, predicted versus actual tolerance, and (most important) the timing for starting food delivery. Although oral nutrition is the more physiological route for feeding, it is seldom possible or sufficient in critically ill patients. Enteral nutrition, in the form of tube feeding, remains the best option in the absence of absolute contraindications, but many other factors should be taken into account. These include the importance of starting early and trying to achieve target nutrients delivery early, especially in previously undernourished or in most severely ill patients, as well as the gastrointestinal intolerance present in the majority of critically ill patients. Parenteral nutrition is an alternative route for nutrition delivery when the enteral one is impossible or insufficient. The most common complication when choosing this route is overfeeding, which has been associated with increased complications rate. On the other hand, the most common complication of enteral nutrition is underfeeding, which has also been associated with worse outcome and even increased mortality. Combining enteral with supplemental parenteral nutrition is therefore a rational approach for providing early and adequate nutritional support in the most severely ill patients.

  18. 29 CFR 1910.37 - Maintenance, safeguards, and operational features for exit routes.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...., sprinkler systems, alarm systems, fire doors, exit lighting) must be in proper working order at all times... visible and marked by a sign reading “Exit.” (3) Each exit route door must be free of decorations or signs that obscure the visibility of the exit route door. (4) If the direction of travel to the exit or...

  19. 29 CFR 1910.37 - Maintenance, safeguards, and operational features for exit routes.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...., sprinkler systems, alarm systems, fire doors, exit lighting) must be in proper working order at all times... visible and marked by a sign reading “Exit.” (3) Each exit route door must be free of decorations or signs that obscure the visibility of the exit route door. (4) If the direction of travel to the exit or...

  20. 29 CFR 1910.37 - Maintenance, safeguards, and operational features for exit routes.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...., sprinkler systems, alarm systems, fire doors, exit lighting) must be in proper working order at all times... visible and marked by a sign reading “Exit.” (3) Each exit route door must be free of decorations or signs that obscure the visibility of the exit route door. (4) If the direction of travel to the exit or...

  1. 29 CFR 1910.37 - Maintenance, safeguards, and operational features for exit routes.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...., sprinkler systems, alarm systems, fire doors, exit lighting) must be in proper working order at all times... visible and marked by a sign reading “Exit.” (3) Each exit route door must be free of decorations or signs that obscure the visibility of the exit route door. (4) If the direction of travel to the exit or...

  2. A Discrete Lagrangian Algorithm for Optimal Routing Problems

    SciTech Connect

    Kosmas, O. T.; Vlachos, D. S.; Simos, T. E.

    2008-11-06

    The ideas of discrete Lagrangian methods for conservative systems are exploited for the construction of algorithms applicable in optimal ship routing problems. The algorithm presented here is based on the discretisation of Hamilton's principle of stationary action Lagrangian and specifically on the direct discretization of the Lagrange-Hamilton principle for a conservative system. Since, in contrast to the differential equations, the discrete Euler-Lagrange equations serve as constrains for the optimization of a given cost functional, in the present work we utilize this feature in order to minimize the cost function for optimal ship routing.

  3. Interaction of Pu(IV,VI) hydroxides/oxides with metal hydroxides/oxides in alkaline media

    SciTech Connect

    Fedoseev, A.M.; Krot, N.N.; Budantseva, N.A.; Bessonov, A.A.; Nikonov, M.V.; Grigoriev, M.S.; Garnov, A.Y.; Perminov, V.P.; Astafurova, L.N.

    1998-08-01

    The primary goal of this investigation was to obtain data on the possibility, extent, and characteristics of interaction of Pu(IV) and (VI) with hydroxides and oxides of d-elements and other metals [Al(III), LA(III), and U(VI)] in alkaline media. Such information is important in fundamental understanding of plutonium disposition and behavior in Hanford Site radioactive tank waste sludge. These results supply essential data for determining criticality safety and in understanding transuranic waste behavior in storage, retrieval, and treatment of Hanford Site tank waste.

  4. Adsorption kinetic and thermodynamic studies of phosphate onto tantalum hydroxide.

    PubMed

    Yu, Shi-Hua; Dong, Xiao-Le; Gong, Hong; Jiang, Heng; Liu, Zhi-Gang

    2012-12-01

    Tantalum hydroxide exhibits the ability for the removal of phosphate from aqueous solution. The kinetic study, adsorption isotherm, thermodynamic study, desorption, and foreign anions effect were examined in batch experiments. The kinetic process was very well described by a pseudo-second-order rate model. The adsorption isotherms showed that phosphate uptake fitted with a Langmuir-type model very well, with an increase of PO4(3-) adsorption capacity from 78.5 to 97.0 mg/g when the temperature increased from 298 to 338 K. The negative values of deltaG(0) and the positive values of deltaH(0) indicated that the phosphate adsorption process was spontaneous and endothermic naturally. While the deltaS(0) values obtained were positive, indicating an increase in randomness at the solid-liquid interface during the adsorption. Foreign anions tests showed that the presence of competitive ions cause minimal interference with the adsorption of phosphate on tantalum hydroxide.

  5. Electrochemical Recovery of Sodium Hydroxide from Alkaline Salt Solution

    SciTech Connect

    Hobbs, D.T.; Edwards, T.B.

    1996-10-01

    A statistically designed set of tests determined the effects of current density, temperature, and the concentrations of nitrate/nitrite, hydroxide and aluminate on the recovery of sodium as sodium hydroxide (caustic) from solutions simulating those produced from the Savannah River Site (SRS) In-Tank Precipitation process. These tests included low nitrate and nitrite concentrations which would be produced by electrolytic nitrate/nitrite destruction. The tests used a two compartment electrochemical cell with a Nafion Type 324 ion-exchange membrane. Caustic was successfully recovered from the waste solutions. Evaluation of the testing results indicated that the transport of sodium across the membrane was not significantly affected by any of the varied parameters. The observed variance in the sodium flux is attributed to experimental errors and variations in the performance characteristics of individual pieces of the organic-based Nafion membrane.Additional testing is recommended to determine the maximum current density, to evaluate the chemical durability of the organic membrane as a function of current density and to compare the durability and performance characteristics of the organic-based Nafion membrane with that of other commercially available organic membranes and the inorganic class of membranes under development by Ceramatec and PNNL.

  6. Ions in water: The microscopic structure of concentrated hydroxide solutions

    NASA Astrophysics Data System (ADS)

    Imberti, S.; Botti, A.; Bruni, F.; Cappa, G.; Ricci, M. A.; Soper, A. K.

    2005-05-01

    Neutron-diffraction data on aqueous solutions of hydroxides, at solute concentrations ranging from 1 solute per 12 water molecules to 1 solute per 3 water molecules, are analyzed by means of a Monte Carlo simulation (empirical potential structure refinement), in order to determine the hydration shell of the OH- in the presence of the smaller alkali metal ions. It is demonstrated that the symmetry argument between H+ and OH- cannot be used, at least in the liquid phase at such high concentrations, for determining the hydroxide hydration shell. Water molecules in the hydration shell of K+ orient their dipole moment at about 45° from the K+-water oxygen director, instead of radially as in the case of the Li+ and Na+ hydration shells. The K+-water oxygen radial distribution function shows a shallower first minimum compared to the other cation-water oxygen functions. The influence of the solutes on the water-water radial distribution functions is shown to have an effect on the water structure equivalent to an increase in the pressure of the water, depending on both ion concentration and ionic radius. The changes of the water structure in the presence of charged solutes and the differences among the hydration shells of the different cations are used to present a qualitative explanation of the observed cation mobility.

  7. Biodiesel synthesis using calcined layered double hydroxide catalysts

    SciTech Connect

    Schumaker, J. Link; Crofcheck, Czarena; TAckett, S. Adam; Santillan-Jimenez, Eduardo; Morgan, Tonya; Ji, Yaying; Crocker, Mark; Toops, Todd J

    2008-01-01

    The catalytic properties of calcined Li-Al, Mg-Al and Mg-Fe layered double hydroxides (LDHs) were examined in two transesterification reactions, namely, the reaction of glyceryl tributyrate with methanol, and the reaction of soybean oil with methanol. While the Li-Al catalysts showed high activity in these reactions at the reflux temperature of methanol, the Mg-Fe and Mg-Al catalysts exhibited much lower methyl ester yields. CO2 TPD measurements revealed the presence of sites of weak, medium and strong basicity on both Mg-Al and Li-Al catalysts, the latter showing higher concentrations of medium and strong base sites; by implication, these are the main sites active in transesterification catalyzed by calcined Li-Al LDHs. Maximum activity was observed for the Li-Al catalysts when a calcination temperature of 450-500 aC was applied, corresponding to decomposition of the layered double hydroxide to the mixed oxide without formation of crystalline lithium aluminate phases.

  8. Hydroxide Degradation Pathways for Substituted Trimethylammonium Cations: A DFT Study

    SciTech Connect

    Long, H.; Kim, K.; Pivovar, B. S.

    2012-05-03

    Substituted trimethylammonium cations serve as small molecule analogues for tetherable cations in anion exchange membranes. In turn, these membranes serve as the basis for alkaline membrane fuel cells by allowing facile conduction of hydroxide. As these cations are susceptible to hydroxide attack, they degrade over time and greatly limit the lifetime of the fuel cell. In this research, we performed density functional theory calculations to investigate the degradation pathways of substituted trimethylammonium cations to probe the relative durability of cation tethering strategies in alkyl and aromatic tethers. Our results show that significant changes in calculated energy barriers occur when substitution groups change. Specifically, we have found that, when available, the Hofmann elimination pathway is the most vulnerable pathway for degradation; however, this barrier is also found to depend on the carbon chain length and number of hydrogens susceptible to Hofmann elimination. S{sub N}2 barriers were also investigated for both methyl groups and substitution groups. The reported findings give important insight into potential tethering strategies for trimethylammonium cations in anion exchange membranes.

  9. Hydroxide Degradation Pathways for Imidazolium Cations. A DFT Study

    SciTech Connect

    Long, H.; Pivovar, B.

    2014-05-15

    Imidazolium cations are promising candidates as covalently tetherable cations for application in anion exchange membranes. They have generated specific interest in alkaline membrane fuel cell applications where ammonium-based cations have been the most commonly applied but have been found to be susceptible to hydroxide attack. In the search for high stability cations, a detailed understanding of the degradation pathways and reaction barriers is required. In this work, we investigate imidazolium and benzimidazolium cations in the presence of hydroxide using density functional theory calculations for their potential in alkaline membrane fuel cells. Moreover, the dominant degradation pathway for these cations is predicted to be the nucleophilic addition–elimination pathway at the C-2 atom position on the imidazolium ring. Steric interferences, introduced by substitutions at the C-2, C-4, and C-5 atom positions, were investigated and found to have a significant, positive impact on calculated degradation energy barriers. Benzimidazolium cations, with their larger conjugated systems, are predicted to degrade much faster than their imidazolium counterparts. Our results provide important insight into designing stable cations for anion exchange membranes. Some of the molecules studied have significantly increased degradation energy barriers suggesting that they could possess significantly improved (several orders of magnitude) durability compared to traditional cations and potentially enable new applications.

  10. Experimental and Theoretical Studies of Volatile Metal Hydroxides

    NASA Technical Reports Server (NTRS)

    Myers, Dwight L.; Jacobson, Nathan S.

    2015-01-01

    Modern superalloys used in the construction of turbomachinery contain a wide range of metals in trace quantities. In addition, metal oxides and silicon dioxide are used to form Thermal Barrier Coatings (TBC) to protect the underlying metal in turbine blades. Formation of volatile hydroxides at elevated temperatures is an important mechanism for corrosion of metal alloys or oxides in combustion environments (N. Jacobson, D. Myers, E. Opila, and E. Copland, J. Phys. Chem. Solids 66, 471-478, 2005). Thermodynamic data is essential to proper design of components of modern gas turbines. It is necessary to first establish the identity of volatile hydroxides formed from the reaction of a given system with high temperature water vapor, and then to determine the equilibrium pressures of the species under operating conditions. Theoretical calculations of reaction energies are an important check of experimental results. This presentation reports results for several important systems: Si-O-H, Cr-O-H, Al-O-H, Ti-O-H, and ongoing studies of Ta-O-H.

  11. Ions in water: the microscopic structure of concentrated hydroxide solutions.

    PubMed

    Imberti, S; Botti, A; Bruni, F; Cappa, G; Ricci, M A; Soper, A K

    2005-05-15

    Neutron-diffraction data on aqueous solutions of hydroxides, at solute concentrations ranging from 1 solute per 12 water molecules to 1 solute per 3 water molecules, are analyzed by means of a Monte Carlo simulation (empirical potential structure refinement), in order to determine the hydration shell of the OH- in the presence of the smaller alkali metal ions. It is demonstrated that the symmetry argument between H+ and OH- cannot be used, at least in the liquid phase at such high concentrations, for determining the hydroxide hydration shell. Water molecules in the hydration shell of K+ orient their dipole moment at about 45 degrees from the K+-water oxygen director, instead of radially as in the case of the Li+ and Na+ hydration shells. The K+-water oxygen radial distribution function shows a shallower first minimum compared to the other cation-water oxygen functions. The influence of the solutes on the water-water radial distribution functions is shown to have an effect on the water structure equivalent to an increase in the pressure of the water, depending on both ion concentration and ionic radius. The changes of the water structure in the presence of charged solutes and the differences among the hydration shells of the different cations are used to present a qualitative explanation of the observed cation mobility.

  12. Lithium hydroxide, LiOH, at elevated densities

    SciTech Connect

    Hermann, Andreas; Ashcroft, N. W.; Hoffmann, Roald

    2014-07-14

    We discuss the high-pressure phases of crystalline lithium hydroxide, LiOH. Using first-principles calculations, and assisted by evolutionary structure searches, we reproduce the experimentally known phase transition under pressure, but we suggest that the high-pressure phase LiOH-III be assigned to a new hydrogen-bonded tetragonal structure type that is unique amongst alkali hydroxides. LiOH is at the intersection of both ionic and hydrogen bonding, and we examine the various ensuing structural features and their energetic driving mechanisms. At P = 17 GPa, we predict another phase transition to a new phase, Pbcm-LiOH-IV, which we find to be stable over a wide pressure range. Eventually, at extremely high pressures of 1100 GPa, the ground state of LiOH is predicted to become a polymeric structure with an unusual graphitic oxygen-hydrogen net. However, because of its ionic character, the anticipated metallization of LiOH is much delayed; in fact, its electronic band gap increases monotonically into the TPa pressure range.

  13. Pigeon Navigation: Different Routes Lead to Frankfurt

    PubMed Central

    Schiffner, Ingo; Wiltschko, Roswitha

    2014-01-01

    Background Tracks of pigeons homing to the Frankfurt loft revealed an odd phenomenon: whereas birds returning from the North approach their loft more or less directly in a broad front, pigeons returning from the South choose, from 25 km from home onward, either of two corridors, a direct one and one with a considerable detour to the West. This implies differences in the navigational process. Methodology/Principle Findings Pigeons released at sites at the beginning of the westerly corridor and in this corridor behave just like pigeons returning from farther south, deviating to the west before turning towards their loft. Birds released at sites within the straight corridors, in contrast, take more or less straight routes. The analysis of the short-term correlation dimension, a quantity reflecting the complexity of the system and with it, the number of factors involved in the navigational process, reveals that it is significantly larger in pigeons choosing the westerly corridor than in the birds flying straight - 3.03 vs. 2.85. The difference is small, however, suggesting a different interpretation of the same factors, with some birds apparently preferring particular factors over others. Conclusions The specific regional distribution of the factors which pigeons use to determine their home course seems to provide ambiguous information in the area 25 km south of the loft, resulting in the two corridors. Pigeons appear to navigate by deriving their routes directly from the locally available navigational factors which they interpret in an individual way. The fractal nature of the correlation dimensions indicates that the navigation process of pigeons is chaotic-deterministic; published tracks of migratory birds suggest that this may apply to avian navigation in general. PMID:25391144

  14. Directional gamma detector

    DOEpatents

    LeVert, Francis E.; Cox, Samson A.

    1981-01-01

    An improved directional gamma radiation detector has a collector sandwiched etween two layers of insulation of varying thicknesses. The collector and insulation layers are contained within an evacuated casing, or emitter, which releases electrons upon exposure to gamma radiation. Delayed electrons and electrons entering the collector at oblique angles are attenuated as they pass through the insulation layers on route to the collector.

  15. The Suprachoroidal Route in Glaucoma Surgery

    PubMed Central

    Shaarawy, Tarek

    2016-01-01

    ABSTRACT Glaucoma surgeries targeting the uveoscleral drainage pathways have been drawing more attention lately. Among all the available techniques, procedures focusing on the supra-choroidal space seem particularly promising, by making use of a presumably efficient and secure outflow route and avoiding subconjunctival filtration blebs. The purpose of this review is to assess the efficacy and the security of the different suprachoroidal drainage implants, namely the CyPass Micro-Stent, the iStent Supra, the SOLX Gold Shunt, the Aquashunt, and the STARflo Glaucoma Implant. Most clinical studies seem to currently point toward the direction that there are actual benefits in suprachoroidal surgeries by avoiding bleb-related complications. Nevertheless, even suprachoroidal implants may be subject to scarring and failure. More data are still needed, especially concerning long-term effects, although the approach does seem appealing. How to cite this article: Gigon A, Shaarawy T. The Suprachoroidal Route in Glaucoma Surgery. J Curr Glaucoma Pract 2016;10(1): 13-20. PMID:27231415

  16. Seeded Growth Route to Noble Calcium Carbonate Nanocrystal

    PubMed Central

    Islam, Aminul; Teo, Siow Hwa; Rahman, M. Aminur; Taufiq-Yap, Yun Hin

    2015-01-01

    A solution-phase route has been considered as the most promising route to synthesize noble nanostructures. A majority of their synthesis approaches of calcium carbonate (CaCO3) are based on either using fungi or the CO2 bubbling methods. Here, we approached the preparation of nano-precipitated calcium carbonate single crystal from salmacis sphaeroides in the presence of zwitterionic or cationic biosurfactants without external source of CO2. The calcium carbonate crystals were rhombohedron structure and regularly shaped with side dimension ranging from 33–41 nm. The high degree of morphological control of CaCO3 nanocrystals suggested that surfactants are capable of strongly interacting with the CaCO3 surface and control the nucleation and growth direction of calcium carbonate nanocrystals. Finally, the mechanism of formation of nanocrystals in light of proposed routes was also discussed. PMID:26700479

  17. Seeded Growth Route to Noble Calcium Carbonate Nanocrystal.

    PubMed

    Islam, Aminul; Teo, Siow Hwa; Rahman, M Aminur; Taufiq-Yap, Yun Hin

    2015-01-01

    A solution-phase route has been considered as the most promising route to synthesize noble nanostructures. A majority of their synthesis approaches of calcium carbonate (CaCO3) are based on either using fungi or the CO2 bubbling methods. Here, we approached the preparation of nano-precipitated calcium carbonate single crystal from salmacis sphaeroides in the presence of zwitterionic or cationic biosurfactants without external source of CO2. The calcium carbonate crystals were rhombohedron structure and regularly shaped with side dimension ranging from 33-41 nm. The high degree of morphological control of CaCO3 nanocrystals suggested that surfactants are capable of strongly interacting with the CaCO3 surface and control the nucleation and growth direction of calcium carbonate nanocrystals. Finally, the mechanism of formation of nanocrystals in light of proposed routes was also discussed.

  18. Seeded Growth Route to Noble Calcium Carbonate Nanocrystal.

    PubMed

    Islam, Aminul; Teo, Siow Hwa; Rahman, M Aminur; Taufiq-Yap, Yun Hin

    2015-01-01

    A solution-phase route has been considered as the most promising route to synthesize noble nanostructures. A majority of their synthesis approaches of calcium carbonate (CaCO3) are based on either using fungi or the CO2 bubbling methods. Here, we approached the preparation of nano-precipitated calcium carbonate single crystal from salmacis sphaeroides in the presence of zwitterionic or cationic biosurfactants without external source of CO2. The calcium carbonate crystals were rhombohedron structure and regularly shaped with side dimension ranging from 33-41 nm. The high degree of morphological control of CaCO3 nanocrystals suggested that surfactants are capable of strongly interacting with the CaCO3 surface and control the nucleation and growth direction of calcium carbonate nanocrystals. Finally, the mechanism of formation of nanocrystals in light of proposed routes was also discussed. PMID:26700479

  19. Theoretical approach to explore the production routes of astatine radionuclides

    SciTech Connect

    Maiti, Moumita; Lahiri, Susanta

    2009-02-15

    To fulfill the recent thrust of astatine radionuclides in the field of nuclear medicine, various production routes have been explored in the present work. The possible production routes of {sup 209-211}At comprise both light- and heavy-ion-induced reactions at the bombarding energy range starting from threshold to a maximum of 100 MeV. Excitation functions of those radionuclides, produced through various production routes, have been calculated by using nuclear reaction model codes TALYS, ALICE91, and PACE-II and are compared with the available measured data. Contributions of various reaction mechanisms, such as direct, pre-equilibrium, and equilibrium reactions, to the total reaction cross section have been studied using the codes. Results show that the equilibrium reaction dominates in all cases over other reaction mechanisms.

  20. Theoretical approach to explore the production routes of astatine radionuclides

    NASA Astrophysics Data System (ADS)

    Maiti, Moumita; Lahiri, Susanta

    2009-02-01

    To fulfill the recent thrust of astatine radionuclides in the field of nuclear medicine, various production routes have been explored in the present work. The possible production routes of At209-211 comprise both light- and heavy-ion-induced reactions at the bombarding energy range starting from threshold to a maximum of 100 MeV. Excitation functions of those radionuclides, produced through various production routes, have been calculated by using nuclear reaction model codes TALYS, ALICE91, and PACE-II and are compared with the available measured data. Contributions of various reaction mechanisms, such as direct, pre-equilibrium, and equilibrium reactions, to the total reaction cross section have been studied using the codes. Results show that the equilibrium reaction dominates in all cases over other reaction mechanisms.

  1. Direct Routes from Synthesis Gas to Ethylene Glycol.

    ERIC Educational Resources Information Center

    Dombek, B. D.

    1986-01-01

    Discusses the synthesis of ethylene glycol from carbon monoxide and hydrogen using bimetallic catalysts. Although this technology has not been implemented, it illustrates two important future trends, namely, use of bimetallic catalysts and use of coal-derived carbon monoxide and hydrogen as a new feed stock. (JN)

  2. Computerized Bus Routing in San Francisco.

    ERIC Educational Resources Information Center

    Caswell, Peter J.; Jungherr, J. Anton

    1979-01-01

    A computerized routing and scheduling system for the San Francisco Public Schools includes the batch processing of bus route assignments and schedules for all schools and the online terminal processing of daily changes. (Author/MLF)

  3. Microstructure of Modified Layer Produced Using Aluminum Oxy-Hydroxide Nanostructured Powders

    NASA Astrophysics Data System (ADS)

    Kuznetsov, M. A.; Shlyakhova, G. V.; Danilov, V. I.; Zernin, E. A.; Dementyev, S. V.

    2016-04-01

    The paper provides the results of experimental research into the influence of aluminum oxy-hydroxide nano-structured powders on the microstructure of modified layers. It has been demonstrated aluminum oxy-hydroxide nano-structured powders AlO(OH) applied as modifiers bring about the decrease in dendrite dimensions, support equilibrium microstructure formation, and cause the growth of microhardness.

  4. Simple Method for Simultaneous Determination of Carbonate, Sulfite and Hydroxide in Solution

    NASA Astrophysics Data System (ADS)

    Al-Itawi, Hossam I.; Al-Ebaisat, Hamdan; Al-Garaleh, Mazen

    A method is proposed for the simultaneous determination of carbon dioxide and sulphur dioxide in a complex matrices. The method involves salvation of the tow gases in Sodium Hydroxide solution followed by simultaneous determination of the three species (carbonate, sulfite and hydroxide) using conductometric and potentiometric titration. What set this method apart from other determination methods it`s simplicity.

  5. BIOGEOCHEMICAL PROCESSES CONTROLLING ARSENIC SPECIATION AND BIOTRANSFORMATION IN GRANULAR FERRIC HYDROXIDE COATED SAND

    EPA Science Inventory

    Arsenic mobilization from solid phase Fe (III) hydroxides is an issue of concern, as water-borne arsenic can migrate into pristine environments, endangering aquatic and human life. In general, metal oxide (hydroxides) exerts a dominating effect on the fate and transport of arseni...

  6. Fault-tolerant self-routing computer network topology

    SciTech Connect

    Mitchell, T.L.

    1987-01-01

    This document reports on the development and analysis of a new, easily expandable, highly fault tolerant self-routing computer network topology. The topology applies equally to any general-purpose computer-networking environment, whether local, metropolitan, or wide area. This new connectivity scheme is named the spiral topology because the architecture is built around modules of four computer nodes each, connected by top and bottom spirals. The spiral topology features a simple internal self-routing algorithm that adapts quickly, and automatically, to failed nodes and links. The six most important direct consequences of the spiral computer-network architecture are the topology's (1) ease of expansion; (2) fast, on-the-fly self-routing; (3) extremely high tolerance to network faults; (4) increased network security; (5) potential for the total elimination of store and forward transmissions due to routing decision delays; and (6) rendering the maximum path length issue moots. The fast on-the-fly routing capability of the spiral topology makes it highly amenable to fiber topic communications in any networking environment.

  7. Blind Alley Aware ACO Routing Algorithm

    NASA Astrophysics Data System (ADS)

    Yoshikawa, Masaya; Otani, Kazuo

    2010-10-01

    The routing problem is applied to various engineering fields. Many researchers study this problem. In this paper, we propose a new routing algorithm which is based on Ant Colony Optimization. The proposed algorithm introduces the tabu search mechanism to escape the blind alley. Thus, the proposed algorithm enables to find the shortest route, even if the map data contains the blind alley. Experiments using map data prove the effectiveness in comparison with Dijkstra algorithm which is the most popular conventional routing algorithm.

  8. Multicast Routing of Hierarchical Data

    NASA Technical Reports Server (NTRS)

    Shacham, Nachum

    1992-01-01

    The issue of multicast of broadband, real-time data in a heterogeneous environment, in which the data recipients differ in their reception abilities, is considered. Traditional multicast schemes, which are designed to deliver all the source data to all recipients, offer limited performance in such an environment, since they must either force the source to overcompress its signal or restrict the destination population to those who can receive the full signal. We present an approach for resolving this issue by combining hierarchical source coding techniques, which allow recipients to trade off reception bandwidth for signal quality, and sophisticated routing algorithms that deliver to each destination the maximum possible signal quality. The field of hierarchical coding is briefly surveyed and new multicast routing algorithms are presented. The algorithms are compared in terms of network utilization efficiency, lengths of paths, and the required mechanisms for forwarding packets on the resulting paths.

  9. Daisy Found on 'Route 66'

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This composite image from the panoramic camera on NASA's Mars Exploration Rover Spirit gives an approximately true-color rendering of a daisy-like pattern of brushed circles that Spirit produced on a rock called 'Route 66.' Spirit used the rock abrasion tool to complete this 6-position 'RAT daisy' on sol 99. It took this image on sol 100, April 14, 2004.

    The purpose for these large brushings is to create a large enough patch of treated surface area for the miniature thermal emission spectrometer to analyze. Scientists had previously conducted a brushing like this one on the rock 'Mazatzal.' The brushed area of Route 66 looks very different from the brushed area of Mazatzal, leading scientists to think that the rocks although both light in tone actually have different coating types.

  10. Different "routes" to a cognitive map: dissociable forms of spatial knowledge derived from route and cartographic map learning.

    PubMed

    Zhang, Hui; Zherdeva, Ksenia; Ekstrom, Arne D

    2014-10-01

    An important, but as yet incompletely resolved, issue is whether spatial knowledge acquired during navigation differs significantly from that acquired by studying a cartographic map. This, in turn, is relevant to understanding the generalizability of the concept of a "cognitive map," which is often likened to a cartographic map. On the basis of previous theoretical proposals, we hypothesized that route and cartographic map learning would produce differences in the dynamics of acquisition of landmark-referenced (allocentric) knowledge, relative to view-referenced (egocentric) knowledge. We compared this model with competing predictions from two other models linked to route versus map learning. To test these ideas, participants repeatedly performed a judgment of relative direction (JRD) and a scene- and orientation-dependent pointing (SOP) task while undergoing route and cartographic map learning of virtual spatial environments. In Experiment 1, we found that map learning led to significantly faster improvements in JRD pointing accuracy than did route learning. In Experiment 2, in contrast, we found that route learning led to more immediate and greater improvements overall in SOP accuracy, as compared to map learning. Comparing Experiments 1 and 2, we found a significant three-way interaction effect, indicating that improvements in performance differed for the JRD versus the SOP task as a function of route versus map learning. We interpreted these findings as suggesting that the learning modality differentially affects the dynamics of how we utilize primarily landmark-referenced versus view-referenced knowledge, suggesting potential differences in how we utilize spatial representations acquired from routes versus cartographic maps.

  11. 14 CFR 121.95 - Route width.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Route width. 121.95 Section 121.95 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR CARRIERS..., FLAG, AND SUPPLEMENTAL OPERATIONS Approval of Routes: Domestic and Flag Operations § 121.95 Route...

  12. 46 CFR 45.175 - Applicable routes.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 2 2012-10-01 2012-10-01 false Applicable routes. 45.175 Section 45.175 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) LOAD LINES GREAT LAKES LOAD LINES Unmanned River Barges on Lake Michigan Routes § 45.175 Applicable routes. This subpart applies to the following...

  13. 46 CFR 45.175 - Applicable routes.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 2 2013-10-01 2013-10-01 false Applicable routes. 45.175 Section 45.175 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) LOAD LINES GREAT LAKES LOAD LINES Unmanned River Barges on Lake Michigan Routes § 45.175 Applicable routes. This subpart applies to the following...

  14. 46 CFR 45.175 - Applicable routes.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 2 2014-10-01 2014-10-01 false Applicable routes. 45.175 Section 45.175 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) LOAD LINES GREAT LAKES LOAD LINES Unmanned River Barges on Lake Michigan Routes § 45.175 Applicable routes. This subpart applies to the following...

  15. Make phloroglucinol by hydroperoxide route

    SciTech Connect

    Not Available

    1986-11-01

    This new industrial process produces phloroglucinol (1,3,5-trihydroxybenzene) from 1,3,5-triisopropylbenzene (TIP) by hydroperoxidation. Phloroglucinol is used as a pharmaceutical intermediate, and demand is expected to increase because of its application in diazo photo papers and intermediates for coupling agents. Phloroglucinol by the hydroperoxide route per se is known. However, these processes produce yields far too low for industrial practice. Phloroglucinol is presently manufactured in relatively small quantities from trinitrotoluene by a series of oxidation, decarbonylation, reduction and hydrolysis reactions. The process has safety and production cost problems. The application of phloroglucinol uses has not expanded because of these limitations. Development of a large-scale, more economical process was needed because there is a large potential market for phloroglucinol in photosensitive papers, photographic chemicals and other areas. Sumito Chemical has made extensive study of the hydroperoxide route to introduce hydroxyl groups into aromatic compounds. Commercial plants for cresol and resorcinol via the hydroperoxide route are in operation today.

  16. The effects of lithium hydroxide solution on alkali silica reaction gels created with opal

    SciTech Connect

    Mitchell, Lyndon D.; Beaudoin, James J.; Grattan-Bellew, Patrick

    2004-04-01

    The reaction of Nevada opal with calcium hydroxide, potassium hydroxide and lithium hydroxide solutions was investigated. In addition, opal was exposed to a combined solution of these three hydroxides. The progress of the three reactions was followed using X-ray diffraction (XRD), {sup 29}Si nuclear magnetic resonance (NMR) and scanning electron microscopy (SEM). The XRD results indicated the presence of a low-angle peak exclusive to the lithium-based reactions. The NMR results suggested a change in the silicate structure in the presence of lithium. These techniques indicated that the reaction of the alkali with the opal starting material is inhibited and perhaps stopped in the presence of lithium hydroxide. SEM revealed that the morphology of the reaction products on the surface of the reacted opal grains is markedly different invariably. It was concluded that evidence to support the theory of a protective layer exists and that the nature of the layer varies with ion type.

  17. Rapeseed-straw enzymatic digestibility enhancement by sodium hydroxide treatment under ultrasound irradiation.

    PubMed

    Kang, Kyeong Eop; Jeong, Gwi-Taek; Park, Don-Hee

    2013-08-01

    In this study, we carried out sodium hydroxide and sonication pretreatments of rapeseed straw (Brassica napus) to obtain monosugar suitable for production of biofuels. To optimize the pretreatment conditions, we applied a statistical response-surface methodology. The optimal pretreatment conditions using sodium hydroxide under sonication irradiation were determined to be 75.0 °C, 7.0 % sodium hydroxide, and 6.8 h. For these conditions, we predicted 97.3 % enzymatic digestibility. In repeated experiments to validate the predicted value, 98.9 ± 0.3 % enzymatic digestibility was obtained, which was well within the range of the predicted model. Moreover, sonication irradiation was found to have a good effect on pretreatment in the lower temperature range and at all concentrations of sodium hydroxide. According to scanning electron microscopy images, the surface area and pore size of the pretreated rapeseed straw were modified by the sodium hydroxide pretreatment under sonication irradiation. PMID:23124436

  18. Rapeseed-straw enzymatic digestibility enhancement by sodium hydroxide treatment under ultrasound irradiation.

    PubMed

    Kang, Kyeong Eop; Jeong, Gwi-Taek; Park, Don-Hee

    2013-08-01

    In this study, we carried out sodium hydroxide and sonication pretreatments of rapeseed straw (Brassica napus) to obtain monosugar suitable for production of biofuels. To optimize the pretreatment conditions, we applied a statistical response-surface methodology. The optimal pretreatment conditions using sodium hydroxide under sonication irradiation were determined to be 75.0 °C, 7.0 % sodium hydroxide, and 6.8 h. For these conditions, we predicted 97.3 % enzymatic digestibility. In repeated experiments to validate the predicted value, 98.9 ± 0.3 % enzymatic digestibility was obtained, which was well within the range of the predicted model. Moreover, sonication irradiation was found to have a good effect on pretreatment in the lower temperature range and at all concentrations of sodium hydroxide. According to scanning electron microscopy images, the surface area and pore size of the pretreated rapeseed straw were modified by the sodium hydroxide pretreatment under sonication irradiation.

  19. Comparison of calcium hydroxide and zinc oxide and eugenol pulpectomies in primary teeth of dogs.

    PubMed

    Hendry, J A; Jeansonne, B G; Dummett, C O; Burrell, W

    1982-10-01

    The purpose of this investigation was to compare calcium hydroxide with zinc oxide and eugenol (ZOE) as root canal obturants in the pulpectomy procedure for irreversibly inflamed primary pulps of dogs. Clinical, radiographic, and histologic comparisons of calcium hydroxide and ZOE root canal filling materials were made in forty-two primary premolars of seven mongrel puppies. When the animals were 6 weeks of age, the pulps of all samples teeth were extirpated and the canals left open to the oral environment. The root canals were assigned to calcium hydroxide, ZOE, and control groups, instrumented, and filled 2 weeks later. The animals were killed 1 day, 1 week, 4 weeks, and 12 weeks after filling. Statistical analysis of all categories for comparison at 4 weeks indicated that calcium hydroxide gave significantly more favorable results than ZOE. Canals treated with calcium hydroxide exhibited less inflammation, less resorption, and more hard-tissue apposition than ZOE-treated and control groups.

  20. Silylative decarbonylation: A new route to arylsilanes

    SciTech Connect

    Rich, J.D. )

    1989-07-19

    A new synthetic procedure for the preparation of aromatic chlorosilanes via the palladium-catalyzed reaction of methylchlorodisilanes and aromatic acid chloride is described. The silylative decarbonylation process is solventless, can utilize low metal catalyst loadings (500-1,000 ppm Pd), is carried out under moderate conditions (145{degree}C), and selectively gives aromatic chlorosilanes in good yield, generally 60-85%. The procedure is tolerant of a variety of aromatic substituents, for example, alkyl, halo, nitro, cyano, imide, acid anhydride, etc., and the synthesis of several new substituted aromatic chlorosilanes containing benzoyl chloride and phthalic anhydride moieties is described. Chloromethyldisilane starting reagents are available from the direct reaction of methyl chloride and silicon, making this methodology an attractive synthetic route to functionalized aromatic chlorosilanes.

  1. Cellulose aerogels from aqueous alkali hydroxide-urea solution.

    PubMed

    Cai, Jie; Kimura, Satoshi; Wada, Masahisa; Kuga, Shigenori; Zhang, Lina

    2008-01-01

    Highly porous and strong cellulose aerogels were prepared by gelation of cellulose from aqueous alkali hydroxide/urea solution, followed by drying with supercritical CO2. Their morphology, pore structure, and physical properties were characterized by scanning and transmission electron microscopy, X-ray diffraction, nitrogen adsorption measurements, UV/Vis spectrometry, and tensile tests. The cellulose hydrogel was composed of interconnected about 20 nm wide. By using supercritical CO2 drying, the network structure in the hydrogel was well preserved in the aerogel. The results are preliminary but demonstrate the ability of this method to give cellulose aerogels of large surface areas (400-500 m2 g(-1)) which may be useful as adsorbents, heat/sound insulators, filters, catalyst supports, or carbon aerogel precursors. PMID:18605678

  2. Layered Double Hydroxide-Based Nanocarriers for Drug Delivery

    PubMed Central

    Bi, Xue; Zhang, Hui; Dou, Liguang

    2014-01-01

    Biocompatible clay materials have attracted particular attention as the efficient drug delivery systems (DDS). In this article, we review developments in the use of layered double hydroxides (LDHs) for controlled drug release and delivery. We show how advances in the ability to synthesize intercalated structures have a significant influence on the development of new applications of these materials. We also show how modification and/or functionalization can lead to new biotechnological and biomedical applications. This review highlights the most recent progresses in research on LDH-based controlled drug delivery systems, focusing mainly on: (i) DDS with cardiovascular drugs as guests; (ii) DDS with anti-inflammatory drugs as guests; and (iii) DDS with anti-cancer drugs as guests. Finally, future prospects for LDH-based drug carriers are also discussed. PMID:24940733

  3. Deterioration of Parabens in Preserved Magnesium Hydroxide Oral Suspensions

    NASA Astrophysics Data System (ADS)

    Hamedani Morteza, Pirali; Mohamad Reza, Fazeli; Nasrin, Samadi; Ehsan, Nassireslami; Shams Ali, Rezazadeh; Amini, Mohsen

    In this study the chemical stability of methyl and propyl paraben in magnesium hydroxide suspension (pH about 10) was investigated using both real time (32 months incubation at 25±2°C with humidity of 60±5% RH) and also accelerated (3 months incubation at 40±2°C with humidity of 70±5% RH) methods. Preparation with no added preservative was used as control. Concentrations of methyl and propyl paraben decreased to levels lower than the reported MIC values after the first month and fifth months of real time study, respectively. Preservative effectiveness testing against the Pharmacopeal challanging microorganisms in both suspensions with or without parabens conformed the US Pharmacopeia requirements for oral antacids. It is concluded that alkaline pH of the suspension without parabens could preserve the product against Pharmacopeial challenging microorganisms and incorporation of parabens did not add any antimicrobial activity to the test product.

  4. Hydroxide decomposition of dimethylsulfoniopropionate to form dimethylsulfide. [in sea water

    NASA Technical Reports Server (NTRS)

    Dacey, John W. H.; Blough, Neil V.

    1987-01-01

    The kinetics of DMS production resulting from reaction of OH(-) with DMSP were investigated as a function of hydroxide concentration and temperature. The reaction was first-order with respect to DMSP and OH(-). The second order rate constant at 20+/-1 C is 0.0044/M/sec. The activation energy for this reaction is 14.4 kcal/mode. The investigation indicates that the rate of reaction of DMSP with OH(-) is very slow at the pH of seawater, suggesting that DMSP, which may be a major precursor of DMS in seawater, decomposes in the ocean by other mechanisms. A bacterium which produces DMS from DMSP quantitatively at rates many orders of magnitude higher than indicated by OH(-1) decomposition has been cultured, suggesting that enzymatic processes accelerate the production of DMS from DMSP in seawater.

  5. Heterogeneous Catalysis by Polyoxometalate-Intercalated Layered Double Hydroxides

    NASA Astrophysics Data System (ADS)

    Rives, Vicente; Carriazo, Daniel; Martín, Cristina

    The preparation, characterisation and catalytic performance of layered double hydroxides (LDH) with the hydrotalcite-type structure containing different polyoxometalates (POM) in the interlayer are studied. Special attention is paid to the preparation procedures, as they control the properties of the solids formed and thus their catalytic behaviour. The study is extended to solids prepared upon thermal decomposition of these POM-LDH systems. It is concluded that the LDH does not act as a simple support, but that its specific properties, such as nature of the cations in the brucite-like layers, specific surface area and the method followed for its preparation, have an outstanding effect on the final catalytic properties of the POM-LDH systems.

  6. Obstructive airway disease associated with occupational sodium hydroxide inhalation.

    PubMed Central

    Rubin, A E; Bentur, L; Bentur, Y

    1992-01-01

    Sodium hydroxide (NaOH) is well known for its corrosive properties and its ability to generate heat on contact with water. The respiratory effects of industrial exposure to NaOH have, however, never been reported. A 63 year old man worked daily for 20 years cleaning large industrial jam containers by boiling lye (NaOH) solution without using respiratory protective equipment. Physical examination, chest x ray film, pulmonary function tests, and arterial blood gases were all compatible with severe obstructive airway disease with significant air trapping. It is probable that this massive and prolonged occupational exposure to the corrosive effect of NaOH mists induced irritation and burns to the respiratory system, eventually leading to severe obstructive airway disease. PMID:1554619

  7. Extended development of a sodium hydroxide thermal energy storage module

    NASA Technical Reports Server (NTRS)

    Rice, R. E.; Rowny, P. E.; Cohen, B. M.

    1980-01-01

    The post-test evaluation of a single heat exchanger sodium hydroxide thermal energy storage module for use in solar electric generation is reported. Chemical analyses of the storage medium used in the experimental model are presented. The experimental verification of the module performance using an alternate heat transfer fluid, Caloria HT-43, is described. Based on these results, a design analysis of a dual heat exchanger concept within the storage module is presented. A computer model and a reference design for the dual system (storage working fluid/power cycle working fluid) were completed. The dual system is estimated to have a capital cost of approximately one half that of the single heat exchanger concept.

  8. Critical operating parameters for microwave solidification of hydroxide sludge

    SciTech Connect

    Sprenger, G.S.; Eschen, V.G.

    1993-08-01

    Engineers at the Rocky Flats Plant (RFP) have developed an innovative technology for the treatment of homogeneous wet or dry solids which are contaminated with hazardous and/or radioactive materials. The process uses microwave energy to heat and melt the waste into a vitreous final form that is suitable for land disposal. The advantages include a high density, leach resistant, robust waste form; volume and toxicity reduction; favorable economics; in-container treatment; favorable public acceptance; isolated equipment; and instantaneous energy control. Regulatory certification of the final form is accomplished by meeting the limitation specified in EPA`s Toxicity Characteristic Leach Procedure (TCLP). This paper presents the results from a series of TCLP tests performed on a surrogate hydroxide coprecipitation sludge spiked with heavy metals at elevated concentrations. The results are very encouraging and support RFP`s commitment to the use of microwave technology for treatment of various mixed waste streams.

  9. Altering surface characteristics of polypropylene mesh via sodium hydroxide treatment.

    PubMed

    Regis, Shawn; Jassal, Manisha; Mukherjee, Nilay; Bayon, Yves; Scarborough, Nelson; Bhowmick, Sankha

    2012-05-01

    Incisional hernias represent a serious and common complication following laparotomy. The use of synthetic (e.g. polypropylene) meshes to aid repair of these hernias has considerably reduced recurrence rates. While polypropylene is biocompatible and has a long successful clinical history in treating hernias and preventing reherniation, this material may suffer some limitations, particularly in challenging patients at risk of wound failure due to, for example, an exaggerated inflammation reaction, delayed wound healing, and infection. Surface modification of the polypropylene mesh without sacrificing its mechanical properties, critical for hernia repair, represents one way to begin to address these clinical complications. Our hypothesis is treatment of a proprietary polypropylene mesh with sodium hydroxide (NaOH) will increase in vitro NIH/3T3 cell attachment, predictive of earlier and improved cell colonization and tissue integration of polypropylene materials. Our goal is to achieve this altered surface functionality via enhanced removal of chemicals/oils used during material synthesis without compromising the mechanical properties of the mesh. We found that NaOH treatment does not appear to compromise the mechanical strength of the material, despite roughly a 10% decrease in fiber diameter. The treatment increases in vitro NIH/3T3 cell attachment within the first 72 h and this effect is sustained up to 7 days in vitro. This research demonstrates that sodium hydroxide treatment is an efficient way to modify the surface of polypropylene hernia meshes without losing the mechanical integrity of the material. This simple procedure could also allow the attachment of a variety of biomolecules to the polypropylene mesh that may aid in reducing the complications associated with polypropylene meshes today.

  10. Optimization of OSPF Routing in IP Networks

    NASA Astrophysics Data System (ADS)

    Bley, Andreas; Fortz, Bernard; Gourdin, Eric; Holmberg, Kaj; Klopfenstein, Olivier; Pióro, Michał; Tomaszewski, Artur; Ümit, Hakan

    The Internet is a huge world-wide packet switching network comprised of more than 13,000 distinct subnetworks, referred to as Autonomous Systems (ASs) autonomous system AS . They all rely on the Internet Protocol (IP) internet protocol IP for transport of packets across the network. And most of them use shortest path routing protocols shortest path routing!protocols , such as OSPF or IS-IS, to control the routing of IP packets routing!of IP packets within an AS. The idea of the routing is extremely simple — every packet is forwarded on IP links along the shortest route between its source and destination nodes of the AS. The AS network administrator can manage the routing of packets in the AS by supplying the so-called administrative weights of IP links, which specify the link lengths that are used by the routing protocols for their shortest path computations. The main advantage of the shortest path routing policy is its simplicity, allowing for little administrative overhead. From the network engineering perspective, however, shortest path routing can pose problems in achieving satisfactory traffic handling efficiency. As all routing paths depend on the same routing metric routing!metric , it is not possible to configure the routing paths for the communication demands between different pairs of nodes explicitly or individually; the routing can be controlled only indirectly and only as a whole by modifying the routing metric. Thus, one of the main tasks when planning such networks is to find administrative link weights that induce a globally efficient traffic routing

  11. Neighboring and connectivity-aware routing in VANETs.

    PubMed

    Ghafoor, Huma; Koo, Insoo; Gohar, Nasir-ud-Din

    2014-01-01

    A novel position-based routing protocol anchor-based connectivity-aware routing (ACAR) for vehicular ad hoc networks (VANETs) is proposed in this paper to ensure connectivity of routes with more successfully delivered packets. Both buses and cars are considered as vehicular nodes running in both clockwise and anticlockwise directions in a city scenario. Both directions are taken into account for faster communication. ACAR is a hybrid protocol, using both the greedy forwarding approach and the store-carry-and-forward approach to minimize the packet drop rate on the basis of certain assumptions. Our solution to situations that occur when the network is sparse and when any (source or intermediate) node has left its initial position makes this protocol different from those existing in the literature. We consider only vehicle-to-vehicle (V2V) communication in which both the source and destination nodes are moving vehicles. Also, no road-side units are considered. Finally, we compare our protocol with A-STAR (a plausible connectivity-aware routing protocol for city environments), and simulation results in NS-2 show improvement in the number of packets delivered to the destination using fewer hops. Also, we show that ACAR has more successfully-delivered long-distance packets with reasonable packet delay than A-STAR.

  12. 40 CFR 415.60 - Applicability; description of the chlorine and sodium or potassium hydroxide production subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... chlorine and sodium or potassium hydroxide production subcategory. 415.60 Section 415.60 Protection of... MANUFACTURING POINT SOURCE CATEGORY Chlor-alkali Subcategory (Chlorine and Sodium or Potassium Hydroxide Production) § 415.60 Applicability; description of the chlorine and sodium or potassium hydroxide...

  13. 40 CFR 415.60 - Applicability; description of the chlorine and sodium or potassium hydroxide production subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... chlorine and sodium or potassium hydroxide production subcategory. 415.60 Section 415.60 Protection of... MANUFACTURING POINT SOURCE CATEGORY Chlor-alkali Subcategory (Chlorine and Sodium or Potassium Hydroxide Production) § 415.60 Applicability; description of the chlorine and sodium or potassium hydroxide...

  14. 40 CFR 415.60 - Applicability; description of the chlorine and sodium or potassium hydroxide production subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... chlorine and sodium or potassium hydroxide production subcategory. 415.60 Section 415.60 Protection of... MANUFACTURING POINT SOURCE CATEGORY Chlor-alkali Subcategory (Chlorine and Sodium or Potassium Hydroxide Production) § 415.60 Applicability; description of the chlorine and sodium or potassium hydroxide...

  15. 40 CFR 415.60 - Applicability; description of the chlorine and sodium or potassium hydroxide production subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... chlorine and sodium or potassium hydroxide production subcategory. 415.60 Section 415.60 Protection of... MANUFACTURING POINT SOURCE CATEGORY Chlor-alkali Subcategory (Chlorine and Sodium or Potassium Hydroxide Production) § 415.60 Applicability; description of the chlorine and sodium or potassium hydroxide...

  16. 40 CFR 415.60 - Applicability; description of the chlorine and sodium or potassium hydroxide production subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... chlorine and sodium or potassium hydroxide production subcategory. 415.60 Section 415.60 Protection of... MANUFACTURING POINT SOURCE CATEGORY Chlor-alkali Subcategory (Chlorine and Sodium or Potassium Hydroxide Production) § 415.60 Applicability; description of the chlorine and sodium or potassium hydroxide...

  17. An Aluminum Magnesium Hydroxide Stearate-based Skin Barrier Protection Cream Used for the Management of Eczematous Dermatitis

    PubMed Central

    Bhambri, Sanjay; Michaels, Brent

    2008-01-01

    Eczematous dermatoses can often be very difficult to treat. An aluminum magnesium hydroxide stearate-based cream has recently become available for clinical use. Aluminum magnesium hydroxide stearate-based cream provides an alternative option in treating these dermatoses while providing barrier protection against external allergens and irritants. This article reviews various studies evaluating aluminum magnesium hydroxide stearate-based cream. PMID:21212843

  18. Calcium hydroxide nanoparticles for the conservation of cultural heritage: new formulations for the deacidification of cellulose-based artifacts

    NASA Astrophysics Data System (ADS)

    Poggi, G.; Toccafondi, N.; Melita, L. N.; Knowles, J. C.; Bozec, L.; Giorgi, R.; Baglioni, P.

    2014-03-01

    Alkaline earth metal hydroxide nanoparticles dispersions have demonstrated to be efficient for the preservation of cellulose-based artifacts, providing a stable neutral environment and, if in excess, turning into mild alkaline species. New formulations tailored for specific conservation issues have been recently obtained via a solvothermal reaction, starting from bulk metal, and short chain alcohols. Using this synthetic procedure, stable, and high concentrated calcium hydroxide nanoparticles dispersions can be obtained. The characterization of nanoparticles was carried out by dynamic light scattering, transmission electron microscopy and X-ray powder diffraction and showed that the dispersed systems are particularly suitable for the application on porous substrates. In a direct application of this technology, acidic paper and canvas samples were artificially aged after deacidification using calcium hydroxide nanoparticles dispersed in short chain alcohols. Cellulose viscosimetric polymerization degree (DPv), cellulose pyrolysis temperature, and samples' pH were evaluated upon the aging and in terms of protective action arising from the applied treatment. In particular, determinations of DPv clearly showed that the degradation of acidic paper and canvas samples proceeds at higher rates with respect to deacidified samples. These evidences were also confirmed by the thermogravimetric analysis of samples, in which the benefits due to the deacidification treatments are measured in terms of pyrolysis temperature of cellulose. These new formulations of nanoparticles dispersions expand the palette of available tools for the conservation of cellulose-based works of art, such as easel paintings, and manuscripts, potentially opening the way for the intervention on parchment and leather, whose preservation is a particularly challenging task.

  19. Optimal fully adaptive wormhole routing for meshes

    SciTech Connect

    Schwiebert, L.; Jayasimha, D.N.

    1993-12-31

    A deadlock-free fully adaptive routing algorithm for 2D meshes which is optimal in the number of virtual channels required and in the number of restrictions placed on the use of these virtual channels is presented. The routing algorithm imposes less than half as many routing restrictions as any previous fully adaptive routing algorithm. It is also proved that, ignoring symmetry, this routing algorithm is the only fully adaptive routing algorithm that achieves both of these goals. The implementation of the routing algorithm requires relatively simple router control logic. The new algorithm is extended, in a straightforward manner to arbitrary dimension meshes. It needs only 4n-2 virtual channels, the minimum number for an n-dimensional mesh. All previous algorithms require an exponential number of virtual channels in the dimension of the mesh.

  20. Dynamic information routing in complex networks

    NASA Astrophysics Data System (ADS)

    Kirst, Christoph; Timme, Marc; Battaglia, Demian

    2016-04-01

    Flexible information routing fundamentally underlies the function of many biological and artificial networks. Yet, how such systems may specifically communicate and dynamically route information is not well understood. Here we identify a generic mechanism to route information on top of collective dynamical reference states in complex networks. Switching between collective dynamics induces flexible reorganization of information sharing and routing patterns, as quantified by delayed mutual information and transfer entropy measures between activities of a network's units. We demonstrate the power of this mechanism specifically for oscillatory dynamics and analyse how individual unit properties, the network topology and external inputs co-act to systematically organize information routing. For multi-scale, modular architectures, we resolve routing patterns at all levels. Interestingly, local interventions within one sub-network may remotely determine nonlocal network-wide communication. These results help understanding and designing information routing patterns across systems where collective dynamics co-occurs with a communication function.

  1. Dynamic information routing in complex networks

    PubMed Central

    Kirst, Christoph; Timme, Marc; Battaglia, Demian

    2016-01-01

    Flexible information routing fundamentally underlies the function of many biological and artificial networks. Yet, how such systems may specifically communicate and dynamically route information is not well understood. Here we identify a generic mechanism to route information on top of collective dynamical reference states in complex networks. Switching between collective dynamics induces flexible reorganization of information sharing and routing patterns, as quantified by delayed mutual information and transfer entropy measures between activities of a network's units. We demonstrate the power of this mechanism specifically for oscillatory dynamics and analyse how individual unit properties, the network topology and external inputs co-act to systematically organize information routing. For multi-scale, modular architectures, we resolve routing patterns at all levels. Interestingly, local interventions within one sub-network may remotely determine nonlocal network-wide communication. These results help understanding and designing information routing patterns across systems where collective dynamics co-occurs with a communication function. PMID:27067257

  2. Synthesis and characterization of [4-(2,4-dichlorophenoxybutyrate)-zinc layered hydroxide] nanohybrid

    NASA Astrophysics Data System (ADS)

    Hussein, Mohd Zobir; Hashim, Norhayati; Yahaya, Asmah Hj.; Zainal, Zulkarnain

    2010-05-01

    A new layered organic-inorganic nanohybrid material in which an agrochemical, 4-(2,4-dichlorophenoxy)butyrate (DPBA) is intercalated into inorganic interlayers of zinc layered hydroxide (ZLH) was synthesized by direct reaction of aqueous DPBA solution with zinc oxide. The resulting nanohybrid is composed of the organic moieties, DPBA sandwiched between ZLH inorganic interlayers. The nanohybrid afforded well ordered crystalline layered structure, a basal spacing of 29.6 Å, 23.5% carbon (w/w) and 47.9% (w/w) loading of DPBA. FTIR study shows that the absorption bands of the resulting nanohybrid composed the FTIR characteristics of both the DPBA and ZLH which further confirmed the intercalation episode. The intercalated organic moiety in the form of nanohybrid is thermally more stable than its sodium salt. Scanning electron micrograph shows the ZnO precursor has very fine granular structure and transformed into a flake-like when the nanohybrid is formed. This work shows that the nanohybrid of DPBA-ZLH can be synthesized using simple, direct reaction of ZnO and DPBA under aqueous environment for the formation of a new generation of agrochemical.

  3. An embedded route finder and tracing system for a stepped robot

    NASA Astrophysics Data System (ADS)

    Wang, Xiangjun; Li, Zhi; Zhou, Xinling

    2003-09-01

    The paper presents a new embedded sensor method of non-contact automatic route-finding and route-tracing for stepped robot. The final system is designed and integrated into a single hardware PCB with size of 30x30x15 mm3. A line scanning charge couple device (CCD) with 1024 pixels is used to obtain the plane scene of route, and a pair of infrared LED is employed to provide the illumination of the route-finder. Moreover, this route-finder still includes a micro lens, CCD driver, instrumentation pre-amplifier, edge extracting circuit, FPGA circuit for position measure and logic control, direction and state display of the route-finder by LED, moving direction control pins output and power manage circuits. The router-finder for stepped robot has the advantages of simple and fast operation, easy assembly with robot, small volume, high sensitivity and precision for route-finding and tracing. The paper outlines in detail the principle of the route-finding and tracing by edge extraction and edge position measure using a CCD image sensor with a micro lens assisted by infrared illumination and a FPGA circuit. Some relational edge extraction and measure algorithms suitable for embedded system with FPGA are introduced in the paper too. Finally, the actual experiment results are given.

  4. New proteoliposome vaccine formulation from N. meningitidis serogroup B, without aluminum hydroxide, retains its antimeningococcal protectogenic potential as well as Th-1 adjuvant capacity.

    PubMed

    Tamargo, Beatriz; Márquez, Yanet; Ramírez, Wendy; Cedré, Bárbara; Fresno, Manuel; Sierra, Gustavo

    2013-01-01

    Proteoliposomes purified from the Outer Membrane of Neisseria meningitidis B, have been successfully used as core for adjuvants and vaccine formulations. We have tried to increase their structural definition and to conserve their efficacy and stability avoiding the addition of the aluminum hydroxide to the final formulation. Liposomal particle systems were prepared from components of defined molecular structure, such as a Neisseria meningitidis B protein complex, extracted and purified without forming vesicle structures. Liposomes were prepared from a mixture of dioleoyl phosphatidyl serine and cholesterol, using the classical dehydration-rehydration method. Transmission Electron Microscopy (TEM) was used to characterize the liposomes. BALB/c mice were used for animal testing procedures. Analysis of specific IgG response, serum bactericidal activity as well as DTH reaction was carried out. Isolation and purification of mRNA and real-time PCR, was performed to determine the dominating Th lymphokine pattern. The new antimeningococcal formulation without aluminum hydroxide prepared with components of defined molecular structure assembled itself into Neoproteoliposomes (NPL) ranging from 50 to 70 nm in diameter. The extraction and purification of selected membrane proteins to provide the antigen for this new formulation (PD-Tp), as well as the NPL-formulation favors a Th1 response pattern, suggested by the higher percentages of DTH, increased expression of proinflamatory lymphokine mRNAs when administered by intramuscular and intranasal routes. It stimulates a systemic bactericidal antibody response against Neisseria meningitidis B and immunologic memory similar to the Cuban VA-MENGOC-BC vaccine, even at lower dosages and is less reactogenic at the injection site in comparison with the formulation with aluminum hydroxide. This new adjuvant formulation could be applicable to the development of new and improved vaccines against meningococcal disease, and eventually as

  5. Improving Operational Acceptability of Dynamic Weather Routes Through Analysis of Commonly Use Routings

    NASA Technical Reports Server (NTRS)

    Evans, Antony D.; Sridhar, Banavar; McNally, David

    2016-01-01

    The Dynamic Weather Routes (DWR) tool is a ground-based trajectory automation system that continuously and automatically analyzes active in-flight aircraft in en route airspace to find simple modifications to flight plan routes that can save significant flying time, while avoiding weather and considering traffic conflicts, airspace sector congestion, special use airspace, and FAA routing restrictions. Trials of the DWR system have shown that significant delay savings are possible. However, some DWR advised routes are also rejected by dispatchers or modified before being accepted. Similarly, of those sent by dispatchers to flight crews as proposed route change requests, many are not accepted by air traffic control, or are modified before implementation as Center route amendments. Such actions suggest that the operational acceptability of DWR advised route corrections could be improved, which may reduce workload and increase delay savings. This paper analyzes the historical usage of different flight routings, varying from simple waypoint pairs to lengthy strings of waypoints incorporating jet routes, in order to improve DWR route acceptability. An approach is developed that can be incorporated into DWR, advising routings with high historical usage and savings potential similar to that of the nominal DWR advisory. It is hypothesized that modifying a nominal DWR routing to one that is commonly used, and nearby, will result in more actual savings since common routings are generally familiar and operationally acceptable to air traffic control. The approach allows routing segments with high historical usage to be concatenated to form routes that meet all DWR constraints. The relevance of a route's historical usage to its acceptance by dispatchers and air traffic control is quantified by analyzing historical DWR data. Results indicate that while historical usage may be less of a concern to flight dispatchers accepting or rejecting DWR advised route corrections, it may be

  6. ASSOCIATION OF CALCIUM HYDROXIDE AND METRONIDAZOLE IN THE TREATMENT OF DOG'S TEETH WITH CHRONIC PERIAPICAL LESION

    PubMed Central

    Panzarini, Sônia Regina; Souza, Valdir; Holland, Roberto; Dezan, Eloi

    2006-01-01

    One of the primary objectives of endodontic treatment of teeth with pulp necrosis is the elimination of microorganisms from the root canal system, as effectively as possible, especially in cases with chronic periapical lesions. AIM: The purpose of this study was to analyze the response of the periapical tissue of dogs' teeth with chronic periapical lesions to endodontic treatment performed with utilization of metronidazole, calcium hydroxide, and an association of both as root canal dressings. METHODOLOGY: Forty root canals were submitted to pulpectomy and the root canals were kept exposed to the oral environment for 6 months. Then, they were submitted to biomechanical preparation and divided into 4 study groups with 10 specimens: group I – no root canal dressing; group II – calcium hydroxide; group III – metronidazole; group IV – calcium hydroxide associated to metronidazole. After 15 days, the root canals were filled with Fill Canal sealer. After 90 days, the animals were killed and the especimens processed for histological analysis. RESULTS: Calcium hydroxide dressing provided a significantly better outcome compared to other experimental groups (α = 0.01). Also, the results of the association of metronidazole and calcium hydroxide were similar to those observed for the metronidazole group. The worst results were obtained by the no root canal dressing group. CONCLUSION: The use of metronidazole alone or associated with Calcium hydroxide, did not improve periapical healing when compared to Calcium hydroxide dressing. PMID:19089054

  7. Severe tissue necrosis following intra-arterial injection of endodontic calcium hydroxide: a case series.

    PubMed

    Sharma, Sanjay; Hackett, Robert; Webb, Roger; Macpherson, David; Wilson, Alan

    2008-05-01

    We present 2 cases of intra-arterial injection of endodontic calcium hydroxide via the root canal system of molar teeth. Nonsetting calcium hydroxide paste was used as a temporary dressing during endodontic treatment and in both cases delivered via an injectable syringe technique. Retrograde flow of the calcium hydroxide occurred along the artery until its origin where orthograde flow continued to the capillary bed. Case 1 demonstrates calcium hydroxide injected into the distal root canal of a lower second molar resulting in its distribution to the external carotid bed and case 2 demonstrates calcium hydroxide injected into the palatal root of an upper second molar with flow into the infraorbital artery. In both cases this resulted in severe clinical signs and symptoms ending in tissue necrosis. Long-term sequelae included scarring, deformity, and chronic pain. This case series illustrates the high toxicity of calcium hydroxide when displaced into vessels and soft tissues. Caution should be exercised when using injectable systems for endodontic calcium hydroxide. PMID:18442746

  8. The Density of Aqueous Sodium Hydroxide-Sodium Aluminate Solutions: Data Review and Model Development

    SciTech Connect

    Reynolds, J. G.; Bernards, J. K.

    2006-07-01

    The density of Hanford tank waste supernatants affects the design and performance of waste treatment processes. The density of aluminate ion [Al(OH){sub 4}{sup -}] bearing sodium hydroxide solutions is important for describing the caustic leaching processes in the Hanford Waste Treatment Plant Flowsheet. The dissolved aluminate has a particularly large impact on the density of supernatants, but this ion is absent from most density estimation algorithms because of its rarity in most industrial processes. Fortunately, there is a large amount of published data on the density of aqueous sodium-hydroxide-sodium aluminate solutions, which can be used to develop density models. This study reviewed the available data and determined the partial molar volume of sodium hydroxide and sodium aluminate for mixtures of these salts in water by regression. This study determined that much of the published data suffered from a strong correlation between the sodium hydroxide and sodium aluminate concentrations in solution. Nonetheless, there was sufficient un-correlated data to identify and quantify the affect of both hydroxide and aluminate concentration on solution density. The density was found to increase linearly with both hydroxide and aluminate concentrations over a wide composition range. The effect of temperature on the density of aqueous sodium hydroxide-sodium aluminate solutions was found to be statistically significant but small in magnitude. (authors)

  9. Properties and applications of calcium hydroxide in endodontics and dental traumatology.

    PubMed

    Mohammadi, Z; Dummer, P M H

    2011-08-01

    Calcium hydroxide has been included within several materials and antimicrobial formulations that are used in a number of treatment modalities in endodontics. These include, inter-appointment intracanal medicaments, pulp-capping agents and root canal sealers. Calcium hydroxide formulations are also used during treatment of root perforations, root fractures and root resorption and have a role in dental traumatology, for example, following tooth avulsion and luxation injuries. The purpose of this paper is to review the properties and clinical applications of calcium hydroxide in endodontics and dental traumatology including its antibacterial activity, antifungal activity, effect on bacterial biofilms, the synergism between calcium hydroxide and other agents, its effects on the properties of dentine, the diffusion of hydroxyl ions through dentine and its toxicity. Pure calcium hydroxide paste has a high pH (approximately 12.5-12.8) and is classified chemically as a strong base. Its main actions are achieved through the ionic dissociation of Ca(2+) and OH(-) ions and their effect on vital tissues, the induction of hard-tissue deposition and the antibacterial properties. The lethal effects of calcium hydroxide on bacterial cells are probably due to protein denaturation and damage to DNA and cytoplasmic membranes. It has a wide range of antimicrobial activity against common endodontic pathogens but is less effective against Enterococcus faecalis and Candida albicans. Calcium hydroxide is also an effective anti-endotoxin agent. However, its effect on microbial biofilms is controversial.

  10. Hierarchical construction of an ultrathin layered double hydroxide nanoarray for highly-efficient oxygen evolution reaction

    NASA Astrophysics Data System (ADS)

    Yang, Qiu; Li, Tian; Lu, Zhiyi; Sun, Xiaoming; Liu, Junfeng

    2014-09-01

    Efficient and low-cost electrocatalysts for the oxygen evolution reaction (OER) are essential components of renewable energy technologies, such as solar fuel synthesis and water splitting processes for powering fuel cells. Here, ultrathin NiCoFe layered double hydroxide (LDH) nanoplates, which directly grow on a cobalt-based nanowire array, forming a hierarchical nanoarray structure, are constructed as efficient oxygen evolution electrodes. In alkaline media, the ordered ultrathin hierarchical LDH nanoarray electrode shows dramatically increased catalytic activity compared to that of LDH nanoparticles and pure nanowire arrays due to the small size, large surface area, and high porosity of the NiCoFe LDH nanoarray. Only a small water oxidation overpotential (η) of 257 mV is needed for a current density of 80 mA cm-2 with a Tafel slope of 53 mV per decade. The hierarchical LDH nanoarray also shows excellent structural stability in alkaline media. After continuous testing under a high OER current density (~300 mA cm-2) for 10 h, the sample maintains the ordered hierarchical structure with no significant deactivation of the catalytic properties.Efficient and low-cost electrocatalysts for the oxygen evolution reaction (OER) are essential components of renewable energy technologies, such as solar fuel synthesis and water splitting processes for powering fuel cells. Here, ultrathin NiCoFe layered double hydroxide (LDH) nanoplates, which directly grow on a cobalt-based nanowire array, forming a hierarchical nanoarray structure, are constructed as efficient oxygen evolution electrodes. In alkaline media, the ordered ultrathin hierarchical LDH nanoarray electrode shows dramatically increased catalytic activity compared to that of LDH nanoparticles and pure nanowire arrays due to the small size, large surface area, and high porosity of the NiCoFe LDH nanoarray. Only a small water oxidation overpotential (η) of 257 mV is needed for a current density of 80 mA cm-2 with a

  11. Trapping Aluminum Hydroxide Clusters with Trisilanols during Speciation in Aluminum(III)-Water Systems: Reproducible, Large Scale Access to Molecular Aluminate Models.

    PubMed

    Lokare, Kapil Shyam; Frank, Nicolas; Braun-Cula, Beatrice; Goikoetxea, Itziar; Sauer, Joachim; Limberg, Christian

    2016-09-26

    To gain molecular level insights into the properties of certain functions and units of extended oxides/hydroxides, suitable molecular model compounds are needed. As an attractive route to access such compounds the trapping of early intermediates during the hydrolysis of suitable precursor compounds with the aid of stabilizing ligands is conceivable, which was tested for the aluminum(III)/water system. Indeed, trisilanols proved suitable trapping reagents: their presence during the hydrolysis of Al(i) Bu2 H in dependence on the amount of water used allowed for the isolation of tri- and octanuclear aluminum hydroxide cluster complexes [Al3 (μ2 -OH)3 (THF)3 (PhSi(OSiPh2 O)3 )2 ] (1) and [Al8 (μ3 -OH)2 (μ2 -OH)10 (THF)3 (p-anisylSi(OSiPh2 O)3 )4 ] (2). 1 can be regarded as the Al(OH)3 cyclic trimer, where six protons have been replaced by silyl residues. While 2 features a unique [Al8 (μ3 -OH)2 (μ2 -OH)10 ](12+) core. In contrast to most other known aggregates of this type, 1 and 2 can be readily prepared at reasonable scales, dissolve in common solvents, and retain an intact framework even in the presence of excessive amounts of water. This finding paves the way to future research addressing the reactivity of the individual functional groups.

  12. A novel load-balanced fixed routing (LBFR) algorithm for wavelength routed optical networks

    NASA Astrophysics Data System (ADS)

    Shen, Gangxiang; Li, Yongcheng; Peng, Limei

    2011-11-01

    In the wavelength-routed optical transport networks, fixed shortest path routing is one of major lightpath service provisioning strategies, which shows simplicity in network control and operation. Specifically, once a shortest route is found for a node pair, the route is always used for any future lightpath service provisioning, which therefore does not require network control and management system to maintain any active network-wide link state database. On the other hand, the fixed shortest path routing strategy suffers from the disadvantage of unbalanced network traffic load distribution and network congestion because it keeps on employing the same fixed shortest route between each pair of nodes. To avoid the network congestion and meanwhile retain the operational simplicity, in this study we develop a Load-Balanced Fixed Routing (LBFR) algorithm. Through a training process based on a forecasted network traffic load matrix, the proposed algorithm finds a fixed (or few) route(s) for each node pair and employs the fixed route(s) for lightpath service provisioning. Different from the fixed shortest path routes between node pairs, these routes can well balance traffic load within the network when they are used for lightpath service provisioning. Compared to the traditional fixed shortest path routing algorithm, the LBFR algorithm can achieve much better lightpath blocking performance according to our simulation and analytical studies. Moreover, the performance improvement is more significant with the increase of network nodal degree.

  13. Action of hydrochloric acid on aluminum hydroxide-magnesium hydroxide gels and magaldrate: 27Al NMR and pH-stat studies.

    PubMed

    Wilson, G E; Falzone, C J; Johnson, R; Lee, H K

    1985-10-01

    Neutralization of mixtures of aluminum hydroxide-magnesium hydroxide gels and of magaldrate by hydrochloric acid were studied by 27Al NMR under conditions of both equilibrium and kinetic control. Under conditions where equilibrium has been attained, an aluminum NMR signal is detectable for suspensions of the mixed gels and magaldrate only after enough acid has been added to exhaust the acid-neutralizing capacity of the magnesium hydroxide. Mixed gels seem to form several soluble aluminum-containing species as neutralization proceeds. Under the conditions of the modified Beekman neutralization procedure, in which the species concentrations reflect neutralization kinetics, mixed gels show a sharp burst of the hexaaquoaluminum cation as acid is added followed by a slow loss of that cation from solution and an accompanying slow rise in pH. Magaldrate shows a steady increase in the hexaaquoaluminum cation with added acid. Differences between magaldrate and mixed gels are also apparent in pH-stat titrations in which magaldrate displays a biphasic response, contrasting to the two burst phases with an intervening lag phase observed for mixed gels. The results of the 27Al NMR and pH-stat titrations are consistent with the hypotheses that magaldrate is a homogeneous substance with a hydrotalcite-like structure and that mixed gels consist of a magnesium hydroxide core surrounded by aluminum hydroxide.

  14. Evaluation of layered zinc hydroxide nitrate and zinc/nickel double hydroxide salts in the removal of chromate ions from solutions

    NASA Astrophysics Data System (ADS)

    de Oliveira, Henrique Bortolaz; Wypych, Fernando

    2016-11-01

    Layered zinc hydroxide nitrate (ZnHN) and Zn/Ni layered double hydroxide salts were synthesized and used to remove chromate ions from solutions at pH 8.0. The materials were characterized by many instrumental techniques before and after chromate ion removal. ZnHN decomposed after contact with the chromate solution, whereas the layered structure of Zn/Ni hydroxide nitrate (Zn/NiHN) and Zn/Ni hydroxide acetate (Zn/NiHA) remained their layers intact after the topotactic anionic exchange reaction, only changing the basal distances. ZnHN, Zn/NiHN, and Zn/NiHA removed 210.1, 144.8, and 170.1 mg of CrO42-/g of material, respectively. Although the removal values obtained for Zn/NiHN and Zn/NiHA were smaller than the values predicted for the ideal formulas of the solids (194.3 and 192.4 mg of CrO42-/g of material, respectively), the measured capacities were higher than the values achieved with many materials reported in the literature. Kinetic experiments showed the removal reaction was fast. To facilitate the solid/liquid separation process after chromium removal, Zn/Ni layered double hydroxide salts with magnetic supports were also synthesized, and their ability to remove chromate was evaluated.

  15. Reactive transport modeling at uranium in situ recovery sites: uncertainties in uranium sorption on iron hydroxides

    USGS Publications Warehouse

    Johnson, Raymond H.; Tutu, Hlanganani; Brown, Adrian; Figueroa, Linda; Wolkersdorfer, Christian

    2013-01-01

    Geochemical changes that can occur down gradient from uranium in situ recovery (ISR) sites are important for various stakeholders to understand when evaluating potential effects on surrounding groundwater quality. If down gradient solid-phase material consists of sandstone with iron hydroxide coatings (no pyrite or organic carbon), sorption of uranium on iron hydroxides can control uranium mobility. Using one-dimensional reactive transport models with PHREEQC, two different geochemical databases, and various geochemical parameters, the uncertainties in uranium sorption on iron hydroxides are evaluated, because these oxidized zones create a greater risk for future uranium transport than fully reduced zones where uranium generally precipitates.

  16. The effect of aluminum hydroxide dissolution on the bleeding of aluminum lake dyes.

    PubMed

    Desai, A; Peck, G E; Lovell, J E; White, J L; Hem, S L

    1993-10-01

    The effect of pH on the bleeding of FD&C yellow No. 5 aluminum lake and FD&C red No. 40 aluminum lake was investigated. The pH-bleeding profiles corresponded to the pH-solubility profile of aluminum hydroxide. The similarity of the bleeding profiles of both lake dyes and the pH-solubility profile of aluminum hydroxide indicates that pH related bleeding, other than that occurring by competition with anions, is a result of dissolution of the aluminum hydroxide substrate. This dissolution is related to the properties of the substrate rather than to the structure of adsorbed dye.

  17. PROCESS FOR SEPARATING PLUTONIUM BY REPEATED PRECIPITATION WITH AMPHOTERIC HYDROXIDE CARRIERS

    DOEpatents

    Faris, B.F.

    1960-04-01

    A multiple carrier precipitation method is described for separating and recovering plutonium from an aqueous solution. The hydroxide of an amphoteric metal is precipitated in an aqueous plutonium-containing solution. This precipitate, which carries plutonium, is then separated from the supernatant liquid and dissolved in an aqueous hydroxide solution, forming a second plutonium- containing solution. lons of an amphoteric metal which forms an insoluble hydroxide under the conditions existing in this second solution are added to the second solution. The precipitate which forms and which carries plutonium is separated from the supernatant liquid. Amphoteric metals which may be employed are aluminum, bibmuth, copper, cobalt, iron, lanthanum, nickel, and zirconium.

  18. Optoelectronic properties and temperature dependent mechanisms of composite-hydroxide-mediated approach for the synthesis of CdO nanomaterials

    NASA Astrophysics Data System (ADS)

    Khan, Taj Muhammad; Shahid, Tauseef; Zakria, M.; Shakoor, Rana I.

    2015-05-01

    We report the successful synthesis of polycrystalline CdO nanomaterials at various process temperatures in the range from (180°C - 300°C) by a single step, conventionally simple and cost effective approach. The approach is based on hydroxide melts as solvents and termed as composite-hydroxide-mediated (CHM) approach. The effect of growth temperature on particle nucleation and consequently on the fabrication and purity of CdO nanostructures is investigated for a constant reaction time (24 h). As revealed by x-ray diffraction and Raman spectroscopy, CdO nanostructures can be reproduced in high purity with no traces by varying the synthesis temperature. These nanostructures have random orientations and non-uniform distribution with average crystallite sizes varying from 27 nm down to 7 nm. A study of the optical properties, based on photoluminescence, has demonstrated that emission peaks of CdO nanomaterials are centered at 491 nm and 528 nm which signifies purity of the product from the CHM approach. The direct bandgap determined for CdO (2.49 eV - 2.51 eV) exhibits a blue-shift with process temperature. The photoluminescence peak at 491 nm is attributed to near band-edge emission. Based on experimental results size and morphology manipulation, and possible growth mechanisms for the synthesized product are proposed with CHM at low temperature and without surfactant.[Figure not available: see fulltext.

  19. Magnesium-containing layered double hydroxides as orthopaedic implant coating materials--An in vitro and in vivo study.

    PubMed

    Weizbauer, Andreas; Kieke, Marc; Rahim, Muhammad Imran; Angrisani, Gian Luigi; Willbold, Elmar; Diekmann, Julia; Flörkemeier, Thilo; Windhagen, Henning; Müller, Peter Paul; Behrens, Peter; Budde, Stefan

    2016-04-01

    The total hip arthroplasty is one of the most common artificial joint replacement procedures. Several different surface coatings have been shown to improve implant fixation by facilitating bone ingrowth and consequently enhancing the longevity of uncemented orthopaedic hip prostheses. In the present study, two different layered double hydroxides (LDHs), Mg-Fe- and Mg-Al-LDH, were investigated as potential magnesium (Mg)-containing coating materials for orthopaedic applications in comparison to Mg hydroxide (Mg(OH)2). In vitro direct cell compatibility tests were carried out using the murine fibroblast cell line NIH 3T3 and the mouse osteosarcoma cell line MG 63. The host response of bone tissue was evaluated in in vivo experiments with nine rabbits. Two cylindrical pellets (3 × 3 mm) were implanted into each femoral condyle of the left hind leg. The samples were analyzed histologically and with μ-computed tomography (μ-CT) 6 weeks after surgery. An in vitro cytotoxicity test determined that more cells grew on the LDH pellets than on the Mg(OH)2-pellets. The pH value and the Mg(2+) content of the cell culture media were increased after incubation of the cells on the degradable samples. The in vivo tests demonstrated the formation of fibrous capsules around Mg(OH)2 and Mg-Fe-LDH. In contrast, the host response of the Mg-Al-LDH samples indicated that this Mg-containing biomaterial is a potential candidate for implant coating. PMID:25939995

  20. Nickel-Aluminum Layered Double Hydroxide Coating on the Surface of Conductive Substrates by Liquid Phase Deposition.

    PubMed

    Maki, Hideshi; Takigawa, Masashi; Mizuhata, Minoru

    2015-08-12

    The direct synthesis of the adhered Ni-Al LDH thin film onto the surface of electrically conductive substrates by the liquid phase deposition (LPD) reaction is carried out for the development of the positive electrode. The complexation and solution equilibria of the dissolved species in the LPD reaction have been clarified by a theoretical approach, and the LPD reaction conditions for the Ni-Al LDH depositions are shown to be optimized by controlling the fluoride ion concentration and the pH of the LPD reaction solutions. The yields of metal oxides and hydroxides by the LPD method are very sensitive to the supersaturation state of the hydroxide in the reaction solution. The surfaces of conductive substrates are completely covered by the minute mesh-like Ni-Al LDH thin film; furthermore, there is no gap between the surfaces of conductive substrates and the deposited Ni-Al LDH thin film. The active material layer thickness was able to be controlled within the range from 100 nm to 1 μm by the LPD reaction time. The high-crystallinity and the arbitrary-thickness thin films on the conductive substrate surface will be beneficial for the interface control of charge transfer reaction fields and the internal resistance reduction of various secondary batteries.

  1. Near real-time traffic routing

    NASA Technical Reports Server (NTRS)

    Yang, Chaowei (Inventor); Cao, Ying (Inventor); Xie, Jibo (Inventor); Zhou, Bin (Inventor)

    2012-01-01

    A near real-time physical transportation network routing system comprising: a traffic simulation computing grid and a dynamic traffic routing service computing grid. The traffic simulator produces traffic network travel time predictions for a physical transportation network using a traffic simulation model and common input data. The physical transportation network is divided into a multiple sections. Each section has a primary zone and a buffer zone. The traffic simulation computing grid includes multiple of traffic simulation computing nodes. The common input data includes static network characteristics, an origin-destination data table, dynamic traffic information data and historical traffic data. The dynamic traffic routing service computing grid includes multiple dynamic traffic routing computing nodes and generates traffic route(s) using the traffic network travel time predictions.

  2. Cascade defense via routing in complex networks

    NASA Astrophysics Data System (ADS)

    Xu, Xiao-Lan; Du, Wen-Bo; Hong, Chen

    2015-05-01

    As the cascading failures in networked traffic systems are becoming more and more serious, research on cascade defense in complex networks has become a hotspot in recent years. In this paper, we propose a traffic-based cascading failure model, in which each packet in the network has its own source and destination. When cascade is triggered, packets will be redistributed according to a given routing strategy. Here, a global hybrid (GH) routing strategy, which uses the dynamic information of the queue length and the static information of nodes' degree, is proposed to defense the network cascade. Comparing GH strategy with the shortest path (SP) routing, efficient routing (ER) and global dynamic (GD) routing strategies, we found that GH strategy is more effective than other routing strategies in improving the network robustness against cascading failures. Our work provides insight into the robustness of networked traffic systems.

  3. Isomorphic routing on a toroidal mesh

    NASA Technical Reports Server (NTRS)

    Mao, Weizhen; Nicol, David M.

    1993-01-01

    We study a routing problem that arises on SIMD parallel architectures whose communication network forms a toroidal mesh. We assume there exists a set of k message descriptors (xi, yi), where (xi, yi) indicates that the ith message's recipient is offset from its sender by xi hops in one mesh dimension, and yi hops in the other. Every processor has k messages to send, and all processors use the same set of message routing descriptors. The SIMD constraint implies that at any routing step, every processor is actively routing messages with the same descriptors as any other processor. We call this isomorphic routing. Our objective is to find the isomorphic routing schedule with least makespan. We consider a number of variations on the problem, yielding complexity results from O(k) to NP-complete. Most of our results follow after we transform the problem into a scheduling problem, where it is related to other well-known scheduling problems.

  4. Reaction route graphs. III. Non-minimal kinetic mechanisms.

    PubMed

    Fishtik, Ilie; Callaghan, Caitlin A; Datta, Ravindra

    2005-02-24

    The concept of reaction route (RR) graphs introduced recently by us for kinetic mechanisms that produce minimal graphs is extended to the problem of non-minimal kinetic mechanisms for the case of a single overall reaction (OR). A RR graph is said to be minimal if all of the stoichiometric numbers in all direct RRs of the mechanism are equal to +/-1 and non-minimal if at least one stoichiometric number in a direct RR is non-unity, e.g., equal to +/-2. For a given mechanism, four unique topological characteristics of RR graphs are defined and enumerated, namely, direct full routes (FRs), empty routes (ERs), intermediate nodes (INs), and terminal nodes (TNs). These are further utilized to construct the RR graphs. One algorithm involves viewing each IN as a central node in a RR sub-graph. As a result, the construction and enumeration of RR graphs are reduced to the problem of balancing the peripheral nodes in the RR sub-graphs according to the list of FRs, ERs, INs, and TNs. An alternate method involves using an independent set of RRs to draw the RR graph while satisfying the INs and TNs. Three examples are presented to illustrate the application of non-minimal RR graph theory.

  5. Advances in optimal routing through computer networks

    NASA Technical Reports Server (NTRS)

    Paz, I. M.

    1977-01-01

    The optimal routing problem is defined. Progress in solving the problem during the previous decade is reviewed, with special emphasis on technical developments made during the last few years. The relationships between the routing, the throughput, and the switching technology used are discussed and their future trends are reviewed. Economic aspects are also briefly considered. Modern technical approaches for handling the routing problems and, more generally, the flow control problems are reviewed.

  6. Superovulation with a single administration of FSH in aluminum hydroxide gel: a novel superovulation method for cattle

    PubMed Central

    KIMURA, Koji

    2016-01-01

    Superovulation (SOV) is a necessary technique to produce large numbers of embryos for embryo transfer. In the conventional methods, follicular stimulating hormone (FSH) is administered to donor cattle twice daily for 3 to 4 days. As this method is labor intensive and stresses cattle, improving this method has been desired. We previously developed a novel and simple SOV method, in which the intramuscular injection of a single dose of FSH in aluminum hydroxide gel (AH-gel) induced the growth of multiple follicles, ovulation and the production of multiple embryos. Here we show that AH-gel can efficiently adsorb FSH and release it effectively in the presence of BSA, a major interstitial protein. When a single intramuscular administration of the FSH and AH-gel mixture was performed to cattle, multiple follicular growth, ovulation and embryo production were induced. However, the treatments caused indurations at the administration sites in the muscle. To reduce the muscle damage, we investigated alternative administration routes and different amounts of aluminum in the gel. By administering the FSH in AH-gel subcutaneously rather than intramuscularly, the amount of aluminum in the gel could be reduced, thus reducing the size of the induration. Moreover, repeated administrations of FSH with AH-gel did not affect the superovulatory response. These results indicate that a single administration of FSH with AH-gel is an effective, novel and practical method for SOV treatment. PMID:27396385

  7. Infrared and x-ray photoelectron spectra of ruthenium oxide films and ruthenium hydroxide

    SciTech Connect

    Belova, I.D.; Shifrina, R.R.; Roginskaya, Yu.E.; Popov, A.V.; Varlamova, T.V.

    1988-03-01

    The IR and x-ray photoelectron spectra of ruthenium hydroxide and of ruthenium oxide films produced by ruthenium chloride hydroxide decomposition at 300, 400, 500, and 600 degrees C were examined in order to obtain information concerning the effect of hydration on the structure and electronic properties of the surface of ruthenium oxide electrodes. It was shown that Ru hydroxide and Ru oxide films contain both water molecules and hydroxyl groups; the latter are retained up to higher temperatures (600 degrees C) in the Ru oxide films than in Ru hydroxide. It was found that water makes the materials studied amorphous, and it also was found that hydration influences their electronic structure (valence band and the electronic core levels of Ru and O).

  8. The mechanism of thermal-gradient mass transfer in the sodium hydroxide-nickel system

    NASA Technical Reports Server (NTRS)

    May, Charles E

    1958-01-01

    "Thermal-gradient mass transfer" was investigated in the molten sodium hydroxide-nickel system. Possible mechanisms (physical, electrochemical, and chemical) are discussed in terms of experimental and theoretical evidence. Experimental details are included in appendixes.

  9. Synergism of Co(II) napthenate and sodium hydroxide in catalytic decomposition of cyclohexylhydroperoxide

    SciTech Connect

    Bondarenko, T.G.; Chichagov, V.N.; Fedoseenko, V.I.; Solyanikov, V.M.

    1980-01-01

    Sodium hydroxide and bivalent cobalt naphthenate are catalysts in the decomposition of cyclohexyl hydroperoxide in cyclohexane and in mixtures have marked synergistic action (decomposition rate constant 0.32 sec/sup -1/).

  10. Neutralization of Hydroxide Ion in Melt-Grown NaCl Crystals

    NASA Technical Reports Server (NTRS)

    Otterson, Dumas A.

    1961-01-01

    Many recent studies of solid-state phenomena, particularly in the area of crystal imperfections, have involved the use of melt-grown NaCl single crystals. Quite often trace impurities in these materials have had a prominent effect on these phenomena. Trace amounts of hydroxide ion have been found in melt-grown NaCl crystals. This paper describes a nondestructive method of neutralizing the hydroxide ion in such crystals. Crystals of similar hydroxide content are maintained at an elevated temperature below the melting point of NaCl in a flowing atmosphere containing. dry hydrogen chloride. Heat treatment is continued until an analysis of the test specimens shows no excess hydroxide ion. A colorimetric method previously described4 is used for this analysis.

  11. METHOD FOR RECOVERING PLUTONIUM VALUES FROM SOLUTION USING A BISMUTH HYDROXIDE CARRIER PRECIPITATE

    DOEpatents

    Faris, B.F.

    1961-04-25

    Carrier precipitation processes for separating plutonium values from aqueous solutions are described. In accordance with the invention a bismuth hydroxide precipitate is formed in the plutonium-containing solution, thereby carrying plutonium values from the solution.

  12. Thermochemistry of calcium oxide and calcium hydroxide in fluoride slags

    NASA Astrophysics Data System (ADS)

    Chattopadhyay, S.; Mitchell, A.

    1990-08-01

    Calcium oxide activity in binary CaF2-CaO and ternary CaF2-CaO-Al2O3 and CaF2-CaO-SiO2 slags has been determined by CO2-slag equilibrium experiments at 1400 °C. The carbonate ca-pacity of these slags has also been computed and compared with sulfide capacity data available in the literature. The similarity in trends suggests the possibility of characterizing carbonate capacity as an alternative basicity index for fluoride-base slags. Slag-D2O equilibrium experi-ments are performed at 1400°C with different fluoride-base slags to determine water solubility at two different partial pressures of D2O, employing a new slag sampling technique. A novel isotope tracer detection technique is employed to analyze water in the slags. The water solubility data found show higher values than the previous literature data by an order of magnitude but show a linear relationship with the square root of water vapor partial pressure. The activity of hydroxide computed from the data is shown to be helpful in estimating water solubility in in-dustrial electroslag remelting (ESR) slags.

  13. Comparison of final irrigation techniques in removal of calcium hydroxide.

    PubMed

    Yücel, Ali Çağın; Gürel, Melek; Güler, Eda; Karabucak, Bekir

    2013-12-01

    The aim of this study was to compare new irrigation systems with a conventional irrigation technique for the removal of inter-appointment calcium hydroxide [Ca(OH)2 ]. Forty-seven extracted human single-rooted teeth were instrumented, and Ca(OH)2 paste was placed into root canals by using a lentulo spiral at the apical third. Teeth were randomly divided into three groups according to different irrigation protocols using a 30-gauge slot-tipped needle, EndoVac system and ProUltra® PiezoFlow™ ultrasonic irrigation system. Scanning electron microscopic images of the selected root canal surfaces (cervical, middle and apical third) were evaluated using a 5-grade scale. The influence of the irrigation system was evaluated using a two-way analysis of variance test and Tukey's test. The EndoVac and PiezoFlow groups demonstrated the lowest scale values (cleanest canals); however, there was no statistical difference between these two groups. The conventional irrigation group exhibited significantly higher scores (P < 0.05). The conventional needle irrigation was not sufficient to remove Ca(OH)2 from the root canal system. Irrigation with EndoVac and PiezoFlow™ ultrasonic irrigation systems improved the removal of the intracanal medicament resulting in cleaner root canal walls.

  14. Potassium hydroxide pulping of rice straw in biorefinery initiatives.

    PubMed

    Jahan, M Sarwar; Haris, Fahmida; Rahman, M Mostafizur; Samaddar, Purabi Rani; Sutradhar, Shrikanta

    2016-11-01

    Rice straw is supposed to be one of the most important lignocellulosic raw materials for pulp mill in Asian countries. The major problem in rice straw pulping is silica. The present research is focused on the separation of silica from the black liquor of rice straw pulping by potassium hydroxide (KOH) and pulp evaluation. Optimum KOH pulping conditions of rice straw were alkali charge 12% as NaOH, cooking temperature 150°C for 2h and material to liquor ratio, 1:6. At this condition pulp yield was 42.4% with kappa number 10.3. KOH pulp bleached to 85% brightness by D0EpD1 bleaching sequences with ClO2 consumption of 25kg/ton of pulp. Silica and lignin were separated from the black liquor of KOH pulping. The amount of recovered silica, lignin and hemicelluloses were 10.4%, 8.4% and 13.0%. The papermaking properties of KOH pulp from rice straw were slightly better than those of corresponding NaOH pulp.

  15. Defluoridation from aqueous solutions by granular ferric hydroxide (GFH).

    PubMed

    Kumar, Eva; Bhatnagar, Amit; Ji, Minkyu; Jung, Woosik; Lee, Sang-Hun; Kim, Sun-Joon; Lee, Giehyeon; Song, Hocheol; Choi, Jae-Young; Yang, Jung-Seok; Jeon, Byong-Hun

    2009-02-01

    This research was undertaken to evaluate the feasibility of granular ferric hydroxide (GFH) for fluoride removal from aqueous solutions. Batch experiments were performed to study the influence of various experimental parameters such as contact time (1 min-24h), initial fluoride concentration (1-100 mgL(-1)), temperature (10 and 25 degrees C), pH (3-12) and the presence of competing anions on the adsorption of fluoride on GFH. Kinetic data revealed that the uptake rate of fluoride was rapid in the beginning and 95% adsorption was completed within 10 min and equilibrium was achieved within 60 min. The sorption process was well explained with pseudo-first-order and pore diffusion models. The maximum adsorption capacity of GFH for fluoride removal was 7.0 mgg(-1). The adsorption was found to be an endothermic process and data conform to Langmuir model. The optimum fluoride removal was observed between pH ranges of 4-8. The fluoride adsorption was decreased in the presence of phosphate followed by carbonate and sulphate. Results from this study demonstrated potential utility of GFH that could be developed into a viable technology for fluoride removal from drinking water.

  16. Effect of calcium hydroxide on proinflammatory cytokines and neuropeptides.

    PubMed

    Khan, Asma A; Sun, Xiaoling; Hargreaves, Kenneth M

    2008-11-01

    Calcium hydroxide, a widely used intracanal medicament, is known to exert an antimicrobial effect and to degrade bacterial-derived lipopolysaccharides. However, little is known about the effect of Ca(OH)(2) on endogenous inflammatory mediators such as interleukin-1 alpha (IL-1 alpha), tumor necrosis factor-alpha (TNF-alpha), and calcitonin gene-related peptide (CGRP). This is an important gap in knowledge because these inflammatory mediators play an important role in mediating the pathogenesis of periradicular periodontitis. We tested the hypothesis that Ca(OH)(2) denatures IL-1 alpha, TNF-alpha, and CGRP. Human IL-1 alpha (0.125 ng/mL), TNF-alpha (0.2 ng/mL), and CGRP (0.25 ng/mL) were incubated with Ca(OH)(2) (0.035 mg/mL) for 1-7 days. At the end of the incubation period, the pH of the samples was neutralized, and the concentrations of the mediators were measured by immunoassays. Data were analyzed with one-way analysis of variance and Bonferroni multiple comparison tests. The results indicate that Ca(OH)(2) denatures IL-1 alpha, TNF-alpha, and CGRP by 50%-100% during the testing periods (P < .001). We concluded that denaturation of these proinflammatory mediators is a potential mechanism by which Ca(OH)(2) contributes to the resolution of periradicular periodontitis. PMID:18928847

  17. Potassium hydroxide pulping of rice straw in biorefinery initiatives.

    PubMed

    Jahan, M Sarwar; Haris, Fahmida; Rahman, M Mostafizur; Samaddar, Purabi Rani; Sutradhar, Shrikanta

    2016-11-01

    Rice straw is supposed to be one of the most important lignocellulosic raw materials for pulp mill in Asian countries. The major problem in rice straw pulping is silica. The present research is focused on the separation of silica from the black liquor of rice straw pulping by potassium hydroxide (KOH) and pulp evaluation. Optimum KOH pulping conditions of rice straw were alkali charge 12% as NaOH, cooking temperature 150°C for 2h and material to liquor ratio, 1:6. At this condition pulp yield was 42.4% with kappa number 10.3. KOH pulp bleached to 85% brightness by D0EpD1 bleaching sequences with ClO2 consumption of 25kg/ton of pulp. Silica and lignin were separated from the black liquor of KOH pulping. The amount of recovered silica, lignin and hemicelluloses were 10.4%, 8.4% and 13.0%. The papermaking properties of KOH pulp from rice straw were slightly better than those of corresponding NaOH pulp. PMID:27518034

  18. In vivo toxicity studies of europium hydroxide nanorods in mice

    SciTech Connect

    Patra, Chitta Ranjan Abdel Moneim, Soha S.; Wang, Enfeng; Dutta, Shamit; Patra, Sujata; Eshed, Michal; Mukherjee, Priyabrata; Gedanken, Aharon; Shah, Vijay H.; Mukhopadhyay, Debabrata

    2009-10-01

    Lanthanide nanoparticles and nanorods have been widely used for diagnostic and therapeutic applications in biomedical nanotechnology due to their fluorescence and pro-angiogenic properties to endothelial cells, respectively. Recently, we have demonstrated that europium (III) hydroxide [Eu{sup III}(OH){sub 3}] nanorods, synthesized by the microwave technique and characterized by several physico-chemical techniques, can be used as pro-angiogenic agents which introduce future therapeutic treatment strategies for severe ischemic heart/limb disease, and peripheral ischemic disease. The toxicity of these inorganic nanorods to endothelial cells was supported by several in vitro assays. To determine the in vivo toxicity, these nanorods were administered to mice through intraperitoneal injection (IP) everyday over a period of seven days in a dose dependent (1.25 to 125 mg kg{sup -1} day{sup -1}) and time dependent manner (8-60 days). Bio-distribution of europium elements in different organs was analyzed by inductively coupled plasma mass spectrometry (ICPMS). Short-term (S-T) and long-term (L-T) toxicity studies (mice euthanized on days 8 and 60 for S-T and L-T, respectively) show normal blood hematology and serum clinical chemistry with the exception of a slight elevation of liver enzymes. Histological examination of nanorod-treated vital organs (liver, kidney, spleen and lungs) showed no or only mild histological changes that indicate mild toxicity at the higher dose of nanorods.

  19. Mechanochemical synthesis of low-fluorine doped aluminum hydroxide fluorides

    NASA Astrophysics Data System (ADS)

    Scalise, V.; Scholz, G.; Kemnitz, E.

    2016-11-01

    Different aluminum hydroxide fluorides with varying Al/F molar ratios from 1:1.5 up to 1:0.05 were successfully synthesized by mechanochemical reactions. The characterization of the products by XRD, 27Al and 19F MAS NMR, thermal analysis, nitrogen adsorption and zeta potential techniques allows a detailed understanding of the structure and surface properties of the products. Using γ-Al(OH)3 and β-AlF3·3H2O as OH- and F-sources, respectively, strongly disordered products were obtained with an Al: F molar ratio higher than 1:0.25. The fluorination degree has affected the amount of 4- and 5-fold coordinated Al sites, not present in the reactants. An evolution of the sub-coordinated Al-species has been detected also as a consequence of annealing processes. Obviously, these species affect the phase transition to alumina, by decreasing the transition temperature of the formation of α-Al2O3. Synthesis conditions (milling time, fluorination degree) play a crucial role for the product composition.

  20. Layered-double-hydroxide-modified electrodes: electroanalytical applications.

    PubMed

    Tonelli, Domenica; Scavetta, Erika; Giorgetti, Marco

    2013-01-01

    Two-dimensional inorganic solids, such as layered double hydroxides (LDHs), also defined as anionic clays, have open structures and unique anion-exchange properties which make them very appropriate materials for the immobilization of anions and biomolecules that often bear an overall negative charge. This review aims to describe the important aspects and new developments of electrochemical sensors and biosensors based on LDHs, evidencing the research from our own laboratory and other groups. It is intended to provide an overview of the various types of chemically modified electrodes that have been developed with these 2D layered materials, along with the significant advances made over the last several years. In particular, we report the main methods used for the deposition of LDH films on different substrates, the conductive properties of these materials, the possibility to use them in the development of membranes for potentiometric anion analysis, the early analytical applications of chemically modified electrodes based on the ability of LDHs to preconcentrate redox-active anions and finally the most recent applications exploiting their electrocatalytic properties. Another promising application field of LDHs, when they are employed as host structures for enzymes, is biosensing, which is described considering glucose as an example.