Concentrations of Fe, Mn, Cu, Zn, Co, Ni, Pb, Cd, B, and SiO2 in interstitial waters from bottom sediments of the Atlantis II and Discovery Deeps, Red Sea rift zone

Chemical analyzes show that interstitial waters from ore-bearing bottom sediments of the Atlantis II and Discovery Deeps are enriched in Fe, Mn, Cu, Ni, Co, Zn, Pb, and Cd compared to sea water. Enrichment factors of these trace elements in the interstitial waters of the Atlantis II Deep relative to the sea water vary within the following ranges: for Fe from 100 to 7000, for Mn from 19047 to 32738, for Zn from 500 to 1600, for Pb from 78333 to 190000, for Cu from 107 to 654. Comparison of average weighted concentrations of Fe, Mn, Zn, Pb, Cu, Ni in the bottom sediments and the interstitial waters of the Atlantis II Deep indicates common regularities and good relationship in distribution of these elements along sediment cores. Differences in concentrations and distribution of the studied trace elements in the interstitial waters of the Atlantis II and Discovery Deeps result from different chemical compositions of hydrothermal fluids entering these deeps.

Ni rey ni roque : episodio histórico del reinado de Felipe II, año de 1595 : novela original /

Contiene: Vol. 1: T. I (XXIII, 135) -- T. II (130 p.) -- Vol. 2: T. III (142 p.) -- T. IV (144 p.)

Trudy tretʹi︠a︡go Oblastnogo istoriko-arkheologicheskago sʺi︠e︡zda, byvshago v g. g. Vladimiri︠e︡, 20-26 ii︠u︡ni︠a︡ 1906 goda.

Mode of access: Internet.

Shcho se i︠e︡: suspilʹni kli︠a︡sy, borotʹba kli︠a︡s, burz︠h︡uazii︠a︡, proli︠e︡tarii︠a︡t, kapitalïzm i orhanizat︠s︡ii︠a︡.

At head of title: Partii︠a︡ ukraïnsʹkikh sot︠s︡ii︠a︡listiv-revoli︠u︡t︠s︡ioneriv.

Metales activados de Rieke: parte II; síntesis de Zn*, Cu*, Al*, In* y Ni* y de compuestos orgánicos y organometálicos

En este artículo de la revisión se describen las diferentes rutas para la formación de metales activados de Reike, en particular Zn*, Cu*' Al*, In* y Ni*. Se describe también la síntesisde compuestos orgánicos y organometálicos obtenidos mediante estos metales.

Adsorption of Ni(2+), Zn(2+) and Pb(2+) onto dry biomass of Arthrospira (Spirulina) platensis and Chlorella vulgaris. I. Single metal systems

Adsorption of Ni(2+), Zn(2+) or Pb(2+) by dry biomass of Arthrospira (Spirulina) platensis and Chlorella vulgaris was studied as a function of contact time and initial metal concentration. The zero point of charge calculated for these biosorbents (pH(zpc) 4.0 and 3.4, respectively) and additional pH tests suggested the use of pH in the range 5.0-5.5 for the experiments. The equilibrium isotherms were evaluated in terms of maximum sorption capacity and sorption affinity. The pseudo first and second order kinetic models were considered to interpret the experimental data, and the latter best described the adsorption system. Both the Freundlich and Langmuir models were shown to well describe the sorption isotherms, thus suggesting an intermediate mono/multilayer sorption mechanism. Compared to A. platensis (q(e) = 0.354, 0.495 and 0.508 mmol g(-1) for Ni(2+), Pb(2)+ and Zn(2+), respectively), C. vulgaris behaved as a better biosorbent because of higher equilibrium sorption capacity (q(e) = 0.499, 0.634 and 0.664 mmol g(-1), respectively). The removal efficiency decreased with increasing metal concentration, pointing out a passive adsorption process involving the active sites on the surface of the biomasses. The FT-IR spectroscopy evidenced that ions removal occurred mainly by interaction between metal and carboxylate groups present on both the cell walls. (C) 2011 Elsevier B.V. All rights reserved.

Nickel complexes with tris(2-aminoethyl)amine (tren): [Ni-3(tren)(4)(H2O)(2)][Cr(ox)(3)](2)center dot 6H(2)O (ox = oxalate), {[Ni-2(tren)(3)][ClO4](4)center dot H2O}(n), and [Ni-2(tren)(2)(aepd)][ClO4](4)center dot 2H(2)O (aepd = N-(2-aminoethyl)pyrrolidi

Reaction of K-3[Cr(ox)(3)] (ox = oxalate) with nickel(II) and tris(2-aminoethyl)amine (tren) in aqueous solution resulted in isolation of the bimetallic assembly [Ni-3(tren)(4)(H2O)(2)][Cr(ox)(3)](2). 6H(2)O. The polymeric complex {[Ni-2(tren)(3)][ClO4](4). H2O}(n) has been prepared by reaction of nickel(II) perchlorate and tren in aqueous solution. From the same reaction mixture the complex [Ni-2(tren)(2)(aepd)][ClO4](4). 2H(2)O (aepd = N-(2-aminoethyl)pyrrolidine-3,4-diamine), in which a bridging tren ligand contains a carbon-carbon bond between two arms forming a substituted pyrrolidine, has been isolated. The complexes have been characterized by X-ray crystallography. The magnetic susceptibility (300-4.2 K) and magnetization data (2, 4 K, H = 0-5 T) for {[Ni-2(tren)(3)][ClO4](4). H2O}(n) (300 K , 4.23 mu(B)) exhibit evidence of weak antiferromagnetic coupling and zero field splitting (2J = -1.8 cm(-1); \ D\ = 2 cm(-1)) at low temperature. For [Ni-3(tren)(4)(H2O)(2)][Cr(ox)(3)](2). 6H(2)O the susceptibility data at 300 K are indicative of uncoupled nickel(II) and chromium(III) sites with zero-field splitting and intramolecular antiferromagnetic coupling predicted at low temperature.

Spin-orbit mixing and nephelauxetic effects in the electronic spectra of nickel(II)-encapsulating complexes involving nitrogen and sulfur donors

A study of spin-orbit mixing and nephelauxetic effects in the electronic spectra of nickel(II)-encapsulating complexes involving mixed nitrogen and sulfur donors is reported. As the number of sulfur donors is systematically varied through the series [Ni(N6-xSx)](2+) (x = 0-6), the spin-forbidden (3)A(2)g --> E-1(g) and (3)A(2g) --> (1)A(1g) transitions undergo a considerable reduction in energy whereas the spin-allowed transitions are relatively unchanged. The [Ni(diAMN(6)sar)](2+) and [Ni(AMN(5)Ssar)](2+) complexes exhibit an unusual band shape for the (3)A(2g) --> T-3(2g) transition which is shown to arise from spin-orbit mixing of the E spin-orbit levels associated with the E-1(g) and T-3(2g) states. A significant differential nephelauxetic effect also arises from the covalency differences between the t(2g) and e(g) orbitals with the result that no single set of Racah B and C interelectron repulsion parameters adequately fit the observed spectra. Using a differential covalency ligand-field model, the spectral transitions are successfully reproduced with three independent variables corresponding to 10Dq and the covalency parameters f(t) and f(e), associated with the t(2g) and e(g) orbitals, respectively. The small decrease in f(t) from unity is largely attributed to central-field covalency effects whereas the dramatic reduction in f(e) with increasing number of sulfur donors is a direct consequence of the increased metal-ligand covalency associated with the sulfur donors. Covalency differences between the t(2g) and e(g) orbitals also result in larger 10Dq values than those obtained simply from the energy of the (3)A(2g) --> T-3(2g) spin-allowed transition.

Tratamentos termomecânicos de ligas do sistema Ni-Ti

As ligas de Níquel‑Titânio (Ni‑Ti) são as mais atractivas entre as ligas com memória de forma devido às suas boas propriedades funcionais juntamente com a elevada resistência e melhor ductilidade. As transformações de fases associadas ao efeito de memória de forma (EMF) podem ser em uma etapa, B19’ (martensite) ↔ B2 (austenite), em duas ou em múltiplas etapas, incluindo a fase‑R intermédia dependendo da história térmica e termomecânica da liga. As temperaturas de transformação são geralmente observadas acima da temperatura ambiente para as ligas ricas em Ti, enquanto nas ricas em Ni se situam abaixo da temperatura ambiente. O objectivo da presente dissertação foi o de investigar as modificações nas propriedades funcionais e estruturais em uma liga de Ni‑Ti rica em Ti (49,0%at.Ni‑51,0%at.Ti) sujeita a diferentes tratamentos térmicos e termomecânicos de marforming e ausforming. Para melhor entender os fenómenos presentes nesta liga foi feito um paralelismo com outras duas ligas de Ni‑Ti: (i) equiatómica com EMF acima da temperatura ambiente e (ii) rica em Ni superelástica (SE) à temperatura ambiente. Com o intuito de uma análise completa das transformações de fases foram utilizadas durante ciclos térmicos diversas técnicas de caracterização: Calorimetria Diferencial de Varrimento (DSC), Resistividade Eléctrica (RE), Dilatometria (DT) e Difracção de Raios‑X (DRX) convencional e por radiação sincrotrão – rotina e textura. Foram também utilizadas outras técnicas à temperatura ambiente com o intuito de observar características microestruturais (Microscopia Óptica (MO) e Electrónica de Varrimento (SEM)) e mecânicas (Microdureza e Ultra‑Microdureza Vickers, e Tracção). A liga de Ni‑Ti rica em Ti tem as suas transformações directa e inversa fortemente afectadas pelos tratamentos termomecânicos, devido à formação de fase‑R durante a transformação directa em duas (B2®R®B19’) ou em múltiplas etapas (B2®R, B2®B19’ e R®B19’). Os tratamentos termomecânicos conducentes à sequência de transformação B2®R®B19’ decrescem a temperatura de fim da formação de B19’ para próximo da temperatura ambiente e apresentam maior estabilidade nas temperaturas e histereses de transformação.

Mono(Eta(5)-cyclopentadienyl)metal(II) complexes with thienyl acetylide chromophores: synthesis, electrochemical studies, and first hyperpolarizabilities

A series of mono(eta(5)-cyclopentadienyl)metal-(II) complexes with nitro-substituted thienyl acetylide ligands of general formula [M(eta(5)-C5H5)(L)(C C{C4H2S}(n)NO2)] (M = Fe, L = kappa(2)-DPPE, n = 1,2; M = Ru, L = kappa(2)-DPPE, 2 PPh3, n = 1, 2; M = Ni, L = PPh3, n = 1, 2) has been synthesized and fully characterized by NMR, FT-IR, and UV-Vis spectroscopy. The electrochemical behavior of the complexes was explored by cyclic voltammetry. Quadratic hyperpolarizabilities (beta) of the complexes have been determined by hyper-Rayleigh scattering (HRS) measurements at 1500 nm. The effect of donor abilities of different organometallic fragments on the quadratic hyperpolarizabilities was studied and correlated with spectroscopic and electrochemical data. Density functional theory (DFT) and time-dependent DFT (TDDFT) calculations were employed to get a better understanding of the second-order nonlinear optical properties in these complexes. In this series, the complexity of the push pull systems is revealed; even so, several trends in the second-order hyperpolarizability can still be recognized. In particular, the overall data seem to indicate that the existence of other electronic transitions in addition to the main MLCT clearly controls the effectiveness of the organometallic donor ability on the second-order NLO properties of these push pull systems.

Embedding theorems of function classes, II

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On Hyperbolic once-punctured-torus bundles II. Fractal tessellations of the plane

We describe fractal tessellations of the complex plane that arise naturally from Cannon-Thurston maps associated to complete, hyperbolic, once-punctured-torus bundles. We determine the symmetry groups of these tessellations.

On the upper bound of the number of limit cycles obtained by the second order averaging method II

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