The conserved potassium channel filter can have distinct ion binding profiles: Structural analysis of rubidium, cesium, and barium binding in NaK2K

PubMed Central

Lam, Yee Ling; Zeng, Weizhong; Sauer, David Bryant

2014-01-01

Potassium channels are highly selective for K+ over the smaller Na+. Intriguingly, they are permeable to larger monovalent cations such as Rb+ and Cs+ but are specifically blocked by the similarly sized Ba2+. In this study, we used structural analysis to determine the binding profiles for these permeant and blocking ions in the selectivity filter of the potassium-selective NaK channel mutant NaK2K and also performed permeation experiments using single-channel recordings. Our data revealed that some ion binding properties of NaK2K are distinct from those of the canonical K+ channels KcsA and MthK. Rb+ bound at sites 1, 3, and 4 in NaK2K, as it does in KcsA. Cs+, however, bound predominantly at sites 1 and 3 in NaK2K, whereas it binds at sites 1, 3, and 4 in KcsA. Moreover, Ba2+ binding in NaK2K was distinct from that which has been observed in KcsA and MthK, even though all of these channels show similar Ba2+ block. In the presence of K+, Ba2+ bound to the NaK2K channel at site 3 in conjunction with a K+ at site 1; this led to a prolonged block of the channel (the external K+-dependent Ba2+ lock-in state). In the absence of K+, however, Ba2+ acts as a permeating blocker. We found that, under these conditions, Ba2+ bound at sites 1 or 0 as well as site 3, allowing it to enter the filter from the intracellular side and exit from the extracellular side. The difference in the Ba2+ binding profile in the presence and absence of K+ thus provides a structural explanation for the short and prolonged Ba2+ block observed in NaK2K. PMID:25024267

The conserved potassium channel filter can have distinct ion binding profiles: structural analysis of rubidium, cesium, and barium binding in NaK2K.

PubMed

Lam, Yee Ling; Zeng, Weizhong; Sauer, David Bryant; Jiang, Youxing

2014-08-01

Potassium channels are highly selective for K(+) over the smaller Na(+). Intriguingly, they are permeable to larger monovalent cations such as Rb(+) and Cs(+) but are specifically blocked by the similarly sized Ba(2+). In this study, we used structural analysis to determine the binding profiles for these permeant and blocking ions in the selectivity filter of the potassium-selective NaK channel mutant NaK2K and also performed permeation experiments using single-channel recordings. Our data revealed that some ion binding properties of NaK2K are distinct from those of the canonical K(+) channels KcsA and MthK. Rb(+) bound at sites 1, 3, and 4 in NaK2K, as it does in KcsA. Cs(+), however, bound predominantly at sites 1 and 3 in NaK2K, whereas it binds at sites 1, 3, and 4 in KcsA. Moreover, Ba(2+) binding in NaK2K was distinct from that which has been observed in KcsA and MthK, even though all of these channels show similar Ba(2+) block. In the presence of K(+), Ba(2+) bound to the NaK2K channel at site 3 in conjunction with a K(+) at site 1; this led to a prolonged block of the channel (the external K(+)-dependent Ba(2+) lock-in state). In the absence of K(+), however, Ba(2+) acts as a permeating blocker. We found that, under these conditions, Ba(2+) bound at sites 1 or 0 as well as site 3, allowing it to enter the filter from the intracellular side and exit from the extracellular side. The difference in the Ba(2+) binding profile in the presence and absence of K(+) thus provides a structural explanation for the short and prolonged Ba(2+) block observed in NaK2K. © 2014 Lam et al.

Sr and Nd isotopic and trace element compositions of Quaternary volcanic centers of the Southern Andes

USGS Publications Warehouse

Futa, K.; Stern, C.R.

1988-01-01

Isotopic compositions of samples from six Quaternary volcanoes located in the northern and southern extremities of the Southern Volcanic Zone (SVZ, 33-46??S) of the Andes and from four centers in the Austral Volcanic Zone (AVZ, 49-54??S) range for 87Sr 86Sr from 0.70280 to 0.70591 and for 143Nd 144Nd from 0.51314 to 0.51255. The ranges are significantly greater than previously reported from the southern Andes but are different from the isotopic compositions of volcanoes in the central and northern Andes. Basalts and basaltic andesites from three centers just north of the Chile Rise-Trench triple junction have 87Sr 86Sr, 143Nd 144Nd, La Yb, Ba La, and Hf Lu that lie within the relatively restricted ranges of the basic magmas erupted from the volcanic centers as far north as 35??S in the SVZ of the Andes. The trace element and Sr and Nd isotopic characteristics of these magmas may be explained by source region contamination of subarc asthenosphere, with contaminants derived from subducted pelagic sediments and seawater-altered basalts by dehydration of subducted oceanic lithosphere. In the northern extremity of the SVZ between 33?? and 34??S, basaltic andesites and andesites have higher 87Sr 86Sr, Rb Cs, and Hf Lu, and lower 143Nd 144Nd than basalts and basaltic andesites erupted farther south in the SVZ, which suggests involvement of components derived from the continental crust. In the AVZ, the most primitive sample, high-Mg andesite from the southernmost volcanic center in the Andes (54??S) has Sr and Nd isotopic compositions and K Rb and Ba La similar to MORB. The high La Yb of this sample suggests formation by small degrees of partial melting of subducted MORB with garnet as a residue. Samples from centers farther north in the AVZ show a regionally regular northward increase in SiO2, K2O, Rb, Ba, Ba La, and 87Sr 86Sr and decrease in MgO, Sr, K Rb, Rb Cs, and 143Nd 144Nd, suggesting increasingly greater degrees of fractional crystallization and associated intra-crustal contamination. ?? 1988.

Tularosa Basin Play Fairway Analysis: Water Chemistry

DOE Data Explorer

Adam Brandt

2015-12-15

This shapefile contains 409 well data points on Tularosa Basin Water Chemistry, each of which have a location (UTM), temperature, quartz and Potassium/Magnesium geothermometer; as well as concentrations of chemicals like Mn, Fe, Ba, Sr, Cs, Rb, As, NH4, HCO3, SO4, F, Cl, B, SiO2, Mg, Ca, K, Na, and Li.

Ultracold Polar Molecules

DTIC Science & Technology

2016-04-01

large positive scattering lengths make clouds difficult to overlap (but 85RbCs looked promising), but 85RbCs is difficult because 85Rb is hard to...produce at high densities. We revealed broad Feshbach resonances that we hope will allow production of higher-density 85Rb clouds . We are now...and this makes clouds of 87Rb and Cs hard to overlap. We therefore investi- gated 85RbCs, using the potentials we had developed for 85RbCs, and showed

Two novel nonlinear optical carbonates in the deep-ultraviolet region: KBeCO3F and RbAlCO3F2

PubMed Central

Kang, Lei; Lin, Zheshuai; Qin, Jingui; Chen, Chuangtian

2013-01-01

With the rapid developments of the all-solid-state deep-ultraviolet (deep-UV) lasers, the good nonlinear optical (NLO) crystal applied in this spectral region is currently lacking. Here, we design two novel NLO carbonates KBeCO3F and RbAlCO3F2 from the first-principles theory implemented in the molecular engineering expert system especially for NLO crystals. Both structurally stable crystals possess very large energy band gaps and optical anisotropy, so they would become the very promising deep-UV NLO crystals alternative to KBBF. Recent experimental results on MNCO3F (M = K, Rb, Cs; N = Ca, Sr, Ba) not only confirm our calculations, but also suggest that the synthesis of the KBeCO3F and RbAlCO3F2 crystals is feasible. PMID:23455618

Concentrations of trace elements in marine fish and its risk assessment in Malaysia.

PubMed

Agusa, Tetsuro; Kunito, Takashi; Yasunaga, Genta; Iwata, Hisato; Subramanian, Annamalai; Ismail, Ahmad; Tanabe, Shinsuke

2005-01-01

Concentrations of trace elements (V, Cr, Mn, Co, Cu, Zn, Ga, Se, Rb, Sr, Mo, Ag, Cd, Sn, Sb, Cs, Ba, Hg, Tl, Pb and Bi) were determined in muscle and liver of 12 species of marine fish collected from coastal areas in Malaysia. Levels of V, Cr, Mn, Co, Cu, Zn, Ga, Sr, Mo, Ag, Cd, Sn, Ba and Pb in liver were higher than those in muscle, whereas Rb and Cs concentrations showed the opposite trend. Positive correlations between concentrations in liver and muscle were observed for all the trace elements except Cu and Sn. Copper, Zn, Se, Ag, Cd, Cs and Hg concentrations in bigeye scads from the east coast of the Peninsular Malaysia were higher than those from the west, whereas V showed the opposite trend. The high concentration of V in the west coast might indicate oil contamination in the Strait of Malacca. To evaluate the health risk to Malaysian population through consumption of fish, intake rates of trace elements were estimated on the basis of the concentrations of trace elements in muscle of fish and daily fish consumption. Some specimens of the marine fish had Hg levels higher than the guideline value by US Environmental Protection Agency (EPA), indicating that consumption of these fish at the present rate may be hazardous to Malaysian people. To our knowledge, this is the first study on multielemental accumulation in marine fish from the Malaysian coast.

Phonon dynamics in type-VIII silicon clathrates: Beyond the rattler concept

NASA Astrophysics Data System (ADS)

Norouzzadeh, Payam; Myles, Charles W.; Vashaee, Daryoosh

2017-05-01

Clathrates can form a type of guest-host solid structures that, unlike most crystalline solids, have very low thermal conductivity. It is generally thought that the guest atoms caged inside the host framework act as "rattlers" and induce lattice dynamics disorders responsible for the small thermal conductivity. We performed a systematic study of the lattice dynamical properties of type-VIII clathrates with alkali and alkaline-earth guests, i.e., X8S i46 (X =Na , K, Rb, Cs, Ca, Sr, and Ba). The energy dependent participation ratio (PR) and the atomic participation ratio of phonon modes extracted from density functional theory calculations revealed that the rattler concept is not adequate to describe the effect of fillers as they manifest strong hybridization with the framework. For the case of heavy fillers, such as Rb, Sr, Cs, and Ba, a phonon band gap was formed between the acoustic and optical branches. The calculated PR indicated that the fillers suppress the acoustic phonon modes and change the energy transport mechanism from propagative to diffusive or localized resulting in "phonon-glass" characteristics. This effect is stronger for the heavy fillers. Furthermore, in all cases, the guest insertion depressed the phonon bandwidth, reduced the Debye temperature, and reduced the phonon group velocity, all of which should lead to reduction of the thermal conductivity.

Impact of a systolic parameter, defined as the ratio of right brachial pre-ejection period to ejection time, on the relationship between brachial-ankle pulse wave velocity and left ventricular diastolic function.

PubMed

Hsu, Po-Chao; Lin, Tsung-Hsien; Lee, Chee-Siong; Chu, Chun-Yuan; Su, Ho-Ming; Voon, Wen-Chol; Lai, Wen-Ter; Sheu, Sheng-Hsiung

2011-04-01

Arterial stiffness is correlated with left ventricular (LV) diastolic function as well as susceptibility to LV systolic function. Therefore, if LV systolic function is not known, the relationship between arterial stiffness and LV diastolic function is difficult to determine. A total of 260 patients were included in the study. The brachial-ankle pulse wave velocity (baPWV) and the ratio of right brachial pre-ejection period to ejection time (rbPEP/rbET) were measured using an ABI-form device. Patients were classified into four groups. Groups 1, 2, 3 and 4 were patients with rbPEP/rbET and baPWV below the median, rbPEP/rbET above but baPWV below the median, rbPET/rbET below but baPWV above the median, and rbPET/rbET and baPWV above the median, respectively. The LV ejection fractions in groups 1 and 3 were higher than those in groups 2 and 4 (P<0.001 for all). Patients in group 1 had a lower left atrial volume index (LAVI) and higher early diastolic mitral annular velocity (Ea) than patients in the other groups (P≤0.002). Patients in group 2 had a LAVI and ratio of transmitral E wave velocity to Ea that were comparable to those in groups 3 and 4. In conclusion, rbPEP/rbET had an impact on the relationship between baPWV and LV diastolic function. In patients with high rbPEP/rbET but low baPWV, low baPWV may not indicate good LV diastolic function but implies that cardiac dysfunction may precede vascular dysfunction in such patients. When interpreting the relationship between baPWV and LV diastolic function, the rbPEP/rbET value obtained from the same examination should be considered.

Spin waves and magnetic exchange interactions in insulating Rb(0.89)Fe(1.58)Se(2).

PubMed

Wang, Miaoyin; Fang, Chen; Yao, Dao-Xin; Tan, GuoTai; Harriger, Leland W; Song, Yu; Netherton, Tucker; Zhang, Chenglin; Wang, Meng; Stone, Matthew B; Tian, Wei; Hu, Jiangping; Dai, Pengcheng

2011-12-06

The parent compounds of iron pnictide superconductors are bad metals with a collinear antiferromagnetic structure and Néel temperatures below 220 K. Although alkaline iron selenide A(y)Fe(1.6+x)Se(2) (A=K, Rb, Cs) superconductors are isostructural with iron pnictides, in the vicinity of the undoped limit they are insulators, forming a block antiferromagnetic order and having Néel temperatures of roughly 500 K. Here we show that the spin waves of the insulating antiferromagnet Rb(0.89)Fe(1.58)Se(2) can be accurately described by a local moment Heisenberg Hamiltonian. A fitting analysis of the spin wave spectra reveals that the next-nearest neighbour couplings in Rb(0.89)Fe(1.58)Se(2), (Ba,Ca,Sr)Fe(2)As(2), and Fe(1.05)Te are of similar magnitude. Our results suggest a common origin for the magnetism of all the Fe-based superconductors, despite having different ground states and antiferromagnetic orderings.

Correlations between potassium, rubidium and cesium ((133)Cs and (137)Cs) in sporocarps of Suillus variegatus in a Swedish boreal forest.

PubMed

Vinichuk, M; Rosén, K; Johanson, K J; Dahlberg, A

2011-04-01

An analysis of sporocarps of ectomycorrhizal fungi Suillus variegatus assessed whether cesium ((133)Cs and (137)Cs) uptake was correlated with potassium (K) or rubidium (Rb) uptake. The question was whether intraspecific correlations of Rb, K and (133)Cs mass concentrations with (137)Cs activity concentrations in sporocarps were higher within, rather than among, different fungal species, and if genotypic origin of sporocarps within a population affected uptake and correlation. Sporocarps (n = 51) from a Swedish forest population affected by the fallout after the Chernobyl accident were studied. The concentrations were 31.9 ± 6.79 g kg(-1) for K (mean ± SD, dwt), 0.40 ± 0.09 g kg(-1) for Rb, 8.7 ± 4.36 mg kg(-1) for (133)Cs and 63.7 ± 24.2 kBq kg(-1) for (137)Cs. The mass concentrations of (133)Cs correlated with (137)Cs activity concentrations (r = 0.61). There was correlation between both (133)Cs concentrations (r = 0.75) and (137)Cs activity concentrations (r = 0.44) and Rb, but the (137)Cs/(133)Cs isotopic ratio negatively correlated with Rb concentration. Concentrations of K and Rb were weakly correlated (r = 0.51). The (133)Cs mass concentrations, (137)Cs activity concentrations and (137)Cs/(133)Cs isotopic ratios did not correlate with K concentrations. No differences between, within or, among genotypes in S. variegatus were found. This suggested the relationships between K, Rb, (133)Cs and (137)Cs in sporocarps of S. variegatus is similar to other fungal species. Copyright © 2011 Elsevier Ltd. All rights reserved.

Effects of guest atomic species on the lattice thermal conductivity of type-I silicon clathrate studied via classical molecular dynamics

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

Kumagai, Tomohisa, E-mail: kumagai@criepi.denken.or.jp; Nakamura, Kaoru; Yamada, Susumu

The effects of guest atomic species in Si clathrates on the lattice thermal conductivity were studied using classical molecular dynamics calculations. The interaction between a host atom and a guest atom was described by the Morse potential function while that between host atoms was described by the Tersoff potential. The parameters of the potentials were newly determined for this study such that the potential curves obtained from first-principles calculations for the insertion of a guest atom into a Si cage were successfully reproduced. The lattice thermal conductivities were calculated by using the Green-Kubo method. The experimental lattice thermal conductivity ofmore » Ba{sub 8}Ga{sub 16}Si{sub 30} can be successfully reproduced using the method. As a result, the lattice thermal conductivities of type-I Si clathrates, M{sub 8}Si{sub 46} (M = Na, Mg, K, Ca Rb, Sr, Cs, or Ba), were obtained. It is found that the lattice thermal conductivities of M{sub 8}Si{sub 46}, where M is IIA elements (i.e., M = Mg, Ca, Sr, or Ba) tend to be lower than those of M{sub 8}Si{sub 46}, where M is IA elements (i.e., M = Na, K, Rb, or Cs). Those of {sup m}M{sub 8}Si{sub 46}, where m was artificially modified atomic weight were also obtained. The obtained lattice thermal conductivity can be regarded as a function of a characteristic frequency, f{sub c}. That indicates minimum values around f{sub c}=2-4 THz, which corresponds to the center of the frequencies of the transverse acoustic phonon modes associated with Si cages.« less

Materials by Design - Computational Alloy Design for Corrosion

DTIC Science & Technology

2011-02-01

Es = + 0.33 eV Cs Rb K · ~·Ba Sr ::~ \\ H ~ YCd ./ G B FS A~ Zn " Be• ’f_ Ni?.Au SeA. ’\\ . At-v Rh Ru • Zr Ja Mo Tc _,. • • • pt • lr Nb w...Windows Air Conditioning Autoflight Electrical Power Navigation Engine Exhaust Stabilizer Doors Fuel system Nacelles/Pylons Power Plant Equip...p. 14 ASETSDefense 2011: Sustainable Surface Engineering for Aerospace and Defense Workshop Quantum Mechanics Insights into SCC resistance 3.5 -E 0

The distribution of (137)Cs, K, Rb and Cs in plants in a Sphagnum-dominated peatland in eastern central Sweden.

PubMed

Vinichuk, M; Johanson, K J; Rydin, H; Rosén, K

2010-02-01

We record the distribution of (137)Cs, K, Rb and Cs within individual Sphagnum plants (down to 20cm depth) as well as (137)Cs in vascular plants growing on a peatland in eastern central Sweden. In Calluna vulgaris(137)Cs was mainly located within the green parts, whereas Andromeda polifolia, Eriophorum vaginatum and Vaccinium oxycoccos showed higher (137)Cs activity in roots. Carex rostrata and Menyanthes trifoliata showed variable distribution of (137)Cs within the plants. The patterns of (137)Cs activity concentration distribution as well as K, Rb and Cs concentrations within individual Sphagnum plants were rather similar and were usually highest in the capitula and/or in the subapical segments and lowest in the lower dead segments, which suggests continuous relocation of those elements to the actively growing apical part. The (137)Cs and K showed relatively weak correlations, especially in capitula and living green segments (0-10cm) of the plant (r=0.50). The strongest correlations were revealed between (137)Cs and Rb (r=0.89), and between (137)Cs and stable Cs (r=0.84). This suggests similarities between (137)Cs and Rb in uptake and relocation within the Sphagnum, but that (137)Cs differs from K. Copyright 2009 Elsevier Ltd. All rights reserved.

Phosphate glass useful in high energy lasers

DOEpatents

Hayden, Yuiko T.; Payne, Stephen A.; Hayden, Joseph S.; Campbell, John H.; Aston, Mary Kay; Elder, Melanie L.

1996-01-01

In a high energy laser system utilizing phosphate laser glass components to amplify the laser beam, the laser system requires a generated laser beam having an emission bandwidth of less than 26 nm and the laser glass components consist essentially of (on an oxide composition basis) in mole percent: P{sub 2}O{sub 5}, 50--75; Al{sub 2}O{sub 3}, {gt}0--10; K{sub 2}O, {gt}0--30; MgO, 0--30; CaO, 0--30; Li{sub 2}O, 0--20; Na{sub 2}O, 0--20; Rb{sub 2}O, 0--20; Cs{sub 2}O, 0--20; BeO, 0--20; SrO, 0--20; BaO, 0--20; ZnO, 0--20; PbO, 0--20; B{sub 2}O{sub 3}, 0--10; Y{sub 2}O{sub 3}, 0--10; La{sub 2}O{sub 3}, 0--8; Ln{sub 2}O{sub 3}, 0.01--8; wherein the sum of MgO and CaO is >0--30; the sum of Li{sub 2}O, Na{sub 2}O, Rb{sub 2}O, and Cs{sub 2}O is 0--20; the sum of BeO, SrO, BaO, ZnO, and PbO is 0--20; the sum of B{sub 2}O{sub 3} and Y{sub 2}O{sub 3} is 0--10; and Ln{sub 2}O{sub 3} represents the sum of the oxides of active lasing lanthanides of atomic number 58--71. 21 figs.

Investigations on the direct introduction of cigarette smoke for trace elements analysis by inductively coupled plasma mass spectrometry

NASA Astrophysics Data System (ADS)

Chang, Michael J.; Naworal, John D.; Walker, Kathleen; Connell, Chris T.

2003-11-01

Direct introduction of mainstream cigarette smoke into an inductively coupled plasma mass spectrometry (ICP-MS) has been investigated with respect to its feasibility for on-line analysis of trace elements. An automated apparatus was designed and built interfacing a smoking machine with an ICP-MS for smoke generation, collection, injection and analysis. Major and minor elements present in the particulate phase and the gas phase of mainstream cigarette smoke of 2R4F reference cigarettes have been qualitatively identified by examination of their full mass spectra. This method provides a rapid-screening analysis of the transfer of trace elements into mainstream smoke during cigarette combustion. A full suite of elements present in the whole cigarette smoke has been identified, including As, B, Ba, Br, Cd, Cl, Cs, Cu, Hg, I, K, Li, Mn, Na, Pb, Rb, Sb, Sn, Tl and Zn. Of these elements, the major portions of B, Ba, Cs, Cu, K, Li, Mn, Na, Pb, Rb, Sn, Tl and Zn are present in the particulate phase, whereas the major portion of Hg is present in the gas phase. As, Br, Cd, Cl, I and Sb exist in a distribution between the gas phase and the particulate phase. Depending on the element, the precision of measurement ranges from 5 to 25% in terms of relative standard deviation of peak height and peak area, based on the fourth puff of 2R4F mainstream cigarette smoke analyzed in five smoking replicates.

Phosphate glass useful in high energy lasers

DOEpatents

Hayden, Y.T.; Payne, S.A.; Hayden, J.S.; Campbell, J.H.; Aston, M.K.; Elder, M.L.

1996-06-11

In a high energy laser system utilizing phosphate laser glass components to amplify the laser beam, the laser system requires a generated laser beam having an emission bandwidth of less than 26 nm and the laser glass components consist essentially of (on an oxide composition basis) in mole percent: P{sub 2}O{sub 5}, 50--75; Al{sub 2}O{sub 3}, {gt}0--10; K{sub 2}O, {gt}0--30; MgO, 0--30; CaO, 0--30; Li{sub 2}O, 0--20; Na{sub 2}O, 0--20; Rb{sub 2}O, 0--20; Cs{sub 2}O, 0--20; BeO, 0--20; SrO, 0--20; BaO, 0--20; ZnO, 0--20; PbO, 0--20; B{sub 2}O{sub 3}, 0--10; Y{sub 2}O{sub 3}, 0--10; La{sub 2}O{sub 3}, 0--8; Ln{sub 2}O{sub 3}, 0.01--8; wherein the sum of MgO and CaO is >0--30; the sum of Li{sub 2}O, Na{sub 2}O, Rb{sub 2}O, and Cs{sub 2}O is 0--20; the sum of BeO, SrO, BaO, ZnO, and PbO is 0--20; the sum of B{sub 2}O{sub 3} and Y{sub 2}O{sub 3} is 0--10; and Ln{sub 2}O{sub 3} represents the sum of the oxides of active lasing lanthanides of atomic number 58--71. 21 figs.

Geochemical zoning and early differentiation in the moon

NASA Technical Reports Server (NTRS)

Taylor, S. R.; Jakes, P.

1977-01-01

The volatile elements (e.g., Rb, Pb, Tl, Bi, Cs) seem to have been depleted at the time of lunar accretion. Accordingly, it may be assumed that the moon initially accreted from refractory material. The good correlation between volatile/involatile element ratios (e.g., Cs/U, K/La, K/Zr) in both highland and maria samples means that element distribution in lunar crustal rocks is not governed by volatility differences. This and other evidence encourages the view that the moon was accreted homogeneously. A consequence of homogeneous accretion theories is that very efficient large-scale element fractionation is required to account both for the high near-surface concentrations of refractory elements (e.g., Th, U, REE, Zr, Ba, etc.) and for the Ca-Al-rich crust.

Insight into the structural, electronic, elastic and optical properties of the alkali hydride compounds, XH (X = Rb and Cs)

NASA Astrophysics Data System (ADS)

Jaradat, Raed; Abu-Jafar, Mohammed; Abdelraziq, Issam; Mousa, Ahmad; Ouahrani, Tarik; Khenata, Rabah

2018-04-01

The equilibrium structural parameters, electronic and optical properties of the alkali hydrides RbH and CsH compounds in rock-salt (RS) and cesium chloride (CsCl) structures have been studied using the full-potential linearized augmented plane-wave (FP-LAPW) method. Wu and Cohen generalized gradient approximation (WC-GGA) was used for the exchange-correlation potential to compute the equilibrium structural parameters, such as the lattice constant (a0), the bulk modulus (B) and bulk modulus first order pressure derivative (B'). In addition to the WC-GGA, the modified Becke Johnson (mBJ) scheme has been also used to overcome the underestimation of the band gap energies. RbH and CsH compounds are found to be semiconductors (wide energy-band gap) using the WC-GGA method, while they are insulators using the mBJ-GGA method. Elastic constants, mechanical and thermodynamic properties were obtained by using the IRelast package. RbH and CsH compounds at ambient pressure are mechanically stable in RS and CsCl structures; they satisfy the Born mechanical stability criteria. Elastic constants (Cij), bulk modulus (B), shear modulus (S) and Debye temperatures (θD) of RbH and CsH compounds decrease as the alkali radius increases. The RS structure of these compounds at ambient conditions is mechanically stronger than CsCl structure. RbH and CsH in RS and CsCl structures are suitable as dielectric compounds. The wide direct energy band gap for these compounds make them promising compounds for optoelectronic UV device applications. Both RbH and CsH have a wide absorption region, on the other hand RbH absorption is very huge compared to the CsH absorption, RbH is an excellent absorbent material, maximum absorption regions are located in the middle ultraviolet (MUV) region and far ultraviolet (FUV) region. The absorption coefficient α (w), imaginary part of the dielectric constant ɛ2(w) and the extinction coefficient k(w) vary in the same way. The present calculated results are in good agreement with the experimental data, indicating the high accuracy of the performed calculations and reliability of the obtained results.

Crystal Structure and Thermodynamic Stability of Ba/Ti-Substituted Pollucites for Radioactive Cs/Ba Immobilization

DOE PAGES

Xu, Hongwu; Chavez, Manuel E.; Mitchell, Jeremy N.; ...

2015-04-23

An analogue of the mineral pollucite (CsAlSi 2O 6), CsTiSi 2O 6.5 has a potential host phase for radioactive Cs. However, as 137Cs and 135Cs transmute to 137Ba and 135Ba, respectively, through the beta decay, it is essential to study the structure and stability of this phase upon Cs → Ba substitution. In this work, two series of Ba/Ti-substituted samples, Cs xBa (1-x)/2TiSi 2O 6.5 and Cs xBa 1-xTiSi 2O 7-0.5x, (x = 0.9 and 0.7), were synthesized by high-temperature crystallization from their respective precursors. Synchrotron X-ray diffraction and Rietveld analysis reveal that while Cs xBa (1-x)/2TiSi 2O 6.5 samplesmore » are phase-pure, Cs xBa 1-xTiSi 2O 7-0.5x samples contain Cs3x/(2+x)Ba (1-x)/(2+x)TiSi 2O 6.5 pollucites (i.e., also two-Cs-to-one-Ba substitution) and a secondary phase, fresnoite (Ba2TiSi2O8). Thus, the Cs xBa 1-xTiSi 2O 7-0.5x series is energetically less favorable than Cs xBa (1-x)/2TiSi 2O 6.5. To study the stability systematics of Cs xBa (1-x)/2TiSi 2O 6.5 pollucites, high-temperature calorimetric experiments were performed at 973 K with or without the lead borate solvent. Enthalpies of formation from the constituent oxides (and elements) have thus been derived. Our results show that with increasing Ba/(Cs + Ba) ratio, the thermodynamic stability of these phases decreases with respect to their component oxides. Hence, from the energetic viewpoint, continued Cs → Ba transmutation tends to destabilize the parent silicotitanate pollucite structure. However, the Ba-substituted pollucite co-forms with fresnoite (which incorporates the excess Ba), thereby providing viable ceramic waste forms for all the Ba decay products.« less

Mössbauer Study of Hexavalent Iron Compounds

NASA Astrophysics Data System (ADS)

Dedushenko, S. K.; Perfiliev, Yu. D.; Goldfeld, M. G.; Tsapin, A. I.

2001-11-01

Six crystalline ferrates(VI): K3Na(FeO4)2, K2FeO4, Rb2FeO4, Cs2FeO4, K2Sr(FeO4)2 and BaFeO4, were studied by Mössbauer spectroscopy. Room-temperature spectra of potassium, rubidium and cesium ferrates are single lines, but spectra of barium, potassium strontium and potassium sodium ferrates show a presence of quadrupole interactions. Most of these salts display an antiferromagnetic transition with a Néel temperature within 2 to 8 K range.

Universal two-dimensional characteristics in perovskite-type oxyhydrides ATiO2H (A = Li, Na, K, Rb, Cs)

NASA Astrophysics Data System (ADS)

Sato, Nobuya; Akashi, Ryosuke; Tsuneyuki, Shinji

2017-07-01

A series of unsynthesized perovskite-type oxyhydrides ATiO2H (A = Li, Na, K, Rb, Cs) are investigated by the density functional calculations. These oxyhydrides are stable in the sense of the formation energies for some possible synthesis reactions. They are crystallized into quite similar crystal structures with the long c-axis, and the corner-sharing TiO4H2 octahedra of the ideal perovskite-type structure are deformed into the 5-fold coordinated titanium atoms with the OH plane and the apical oxygen atoms. All of these oxyhydrides exhibit two-dimensional electronic states at the valence band maximum characterized by the in-plane oxygen 2p and the hydrogen 1s orbitals. While the c-axis becomes short as the ionic radius of the A atom becomes small and the two-dimensional characteristics are weakened, the electronic state at the valence band maximum is still characterized as the O-H in-plane state. Additionally, the Born effective charge tensors, spontaneous electric polarizations, dielectric tensors, and piezoelectric tensors are evaluated. It is found that the spontaneous electric polarizations of these oxyhydrides are much larger than that of tetragonal BaTiO3.

First-principles study on the bulk and (1 1 1) surface half-metallicity of KS and RbS in CsCl structure

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

Li, Lei; Lei, Gang; Gao, Qiang

2015-08-15

Graphical abstract: Spin-polarized total and atomic DOS at S-(1 1 1) terminated slab and bulk in CsCl-type RbS. - Highlights: • The half metallic properties of CsCl-type RbS and KS have been studied. • The RbS's and KS's (1 1 1) slabs have been investigated. • Surface energy of RbS's and KS's (1 1 1) slabs are calculated. - Abstract: The electronic and magnetic properties of RbS and KS in CsCl structure have been investigated by using the full-potential local-orbital minimum-basis method. Calculating the relation between the total energies and lattice parameters for RbS and KS, we find out thatmore » the equilibrium lattice parameters are 4.02 Å and 3.84 Å for RbS and KS, respectively. According to our calculations in generalized gradient approximation approximation, both RbS and KS are half-metallic ferromagnets with the magnetic moments of 1 μ{sub B} per formula unit, and band gap of 4.287 eV for RbS and 4.395 eV for KS. We also have studied the electronic and magnetic properties of (1 1 1) surfaces of RbS and KS, and have found out that the half-metallicity of their bulk is preserved in all of those surfaces. Finally, through the calculations of formation energy of RbS and KS, it is found that their thin films are stable in the equilibrium conditions, and the Rb-terminated (1 1 1) slab of RbS and the K-terminated (1 1 1) slab of KS are more stable than their S-terminated (1 1 1) slabs. All of the above properties lead the compounds of RbS and KS in CsCl structure to be promising candidates for spintronic applications.« less

C and RB Fountains:. Recent Results

NASA Astrophysics Data System (ADS)

Bize, S.; Sortais, Y.; Abgrall, M.; Zhang, S.; Calonico, D.; Mandache, C.; Lemonde, P.; Laurent, P.; Santarelli, G.; Salomon, C.; Clairon, A.; Luiten, A.; Tobar, M.

2002-04-01

We discuss the present performance and limits of our Cs and Rb fountains. The BNM/LPTF operates three cold atom clocks: two Cs fountains and a dual Cs-Rb fountain. By using an ultra-stable cryogenic sapphire oscillator to interrogate the atoms the frequency stability reaches 3.6 × 10-14τ-1/2. The accuracy of our fountains is now near 10-15. We discuss here the problems to be solved to reach a 10-16 accuracy. For instance this implies a continuous monitoring of the collisional frequency shift at the percent level in Cs. In contrast, 87Rb cold atom clocks exhibit a collisional shift ~ 100 times smaller than Cs which should lead to a better ultimate accuracy. Comparing the hyperfine energies of atoms with different atomic numbers Z, one can search for a possible violation of the Einstein Equivalence Principle. When interpreted as a test of the stability of the fine structure constant (α = e2/4πγ0ħc), measurements of the ratio νRb/νCs spread over a two year interval show no change of α at the 7 × 10-15/year level.

Dual-species Bose-Einstein condensate of {sup 87}Rb and {sup 133}Cs

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

McCarron, D. J.; Cho, H. W.; Jenkin, D. L.

2011-07-15

We report the formation of a dual-species Bose-Einstein condensate of {sup 87}Rb and {sup 133}Cs in the same trapping potential. Our method exploits the efficient sympathetic cooling of {sup 133}Cs via elastic collisions with {sup 87}Rb, initially in a magnetic quadrupole trap and subsequently in a levitated optical trap. The two condensates each contain up to 2x10{sup 4} atoms and exhibit a striking phase separation, revealing the mixture to be immiscible due to strong repulsive interspecies interactions. Sacrificing all the {sup 87}Rb during the cooling, we create single-species {sup 133}Cs condensates of up to 6x10{sup 4} atoms.

A Simple Model for Fine Structure Transitions in Alkali-Metal Noble-Gas Collisions

DTIC Science & Technology

2015-03-01

63 33 Effect of Scaling the VRG(R) Radial Coupling Fit Parameter, V0, for KHe, KNe, and KAr...64 ix Figure Page 34 Effect of Scaling the VRG(R) Radial Coupling Fit Parameter, V0, for RbHe, RbNe, and...RbAr . . . . . . . . . . . . . . . . . . . . . . . . . 64 35 Effect of Scaling the VRG(R) Radial Coupling Fit Parameter, V0, for CsHe, CsNe, and CsAr

The Northeast Kingdom batholith, Vermont: magmatic evolution and geochemical constraints on the origin of Acadian granitic rocks

USGS Publications Warehouse

Ayuso, R.A.; Arth, Joseph G.

1992-01-01

Five Devonian plutons (West Charleston, Echo Pond, Nulhegan, Derby, and Willoughby) that constitute the Northeast Kingdom batholith in Vermont show wide ranges in elemental abundances and ratios consistent with major crustal contributions during their evolution. The batholith consists of metaluminous quartz gabbro, diorite and quartz monzodiorite, peraluminous granodiorite and granite, and strongly peraluminous leucogranite. Contents of major elements vary systematically with increasingSiO40) and have small negative Eu anomalies. The strongly peraluminous Willoughby leucogranite has unique trace-element abundances and ratios relative to the rest of the batholith, including low contents of Hf, Zr, Sr, and Ba, low values of K/Rb (80-164), Th/Ta (<9), Rb/Cs (7-40), K/Cs (0.1-0.5), Ce/Pb (0.5-4), high values of Rb/Sr (1-18) low to moderate REE contents and light-REE enriched patterns (with small negative Eu anomalies). Flat REE patterns (with large negative Eu anomalies) are found in a small, hydrothermally-altered area characterized by high abundances of Sn (up to 26 ppm), Rb (up to 670 ppm), Li (up to 310 ppm), Ta (up to 13.1 ppm), and U (up to 10 ppm). There is no single mixing trend, fractional crystallization assemblage, or assimilationscheme that accounts for all trace elementvariations from quartz gabbro to granite in the Northeast Kingdom batholith. The plutons originated by mixing mantle-derived components and crustal melts generated at different levels in the heterogeneous lithosphere in a continental collisional environment. Hybrid rocks in the batholith evolved by fractional crystallization and assimilation of country rocks (<50% by mass), and some of the leucogranitic rocks were subsequently disturbed by a mild hydrothermal event that resulted in the deposition of small amounts of sulfide minerals. ?? 1992 Springer-Verlag.

Chitosan hydrogel beads impregnated with hexadecylamine for improved reactive blue 4 adsorption.

PubMed

Vakili, Mohammadtaghi; Rafatullah, Mohd; Ibrahim, Mahamad Hakimi; Abdullah, Ahmad Zuhairi; Salamatinia, Babak; Gholami, Zahra

2016-02-10

Adsorption performance of chitosan (CS) hydrogel beads was investigated after impregnation of CS with hexadecylamine (HDA) as a cationic surfactant, for the elimination of reactive blue 4 (RB4) from wastewater. The CS/HDA beads formed with 3.8% HDA were the most effective adsorbent. The adsorption capacity was increased by 1.43 times from 317 mg/g (CS) to 454 mg/g (CS/HDA). The RB4 removal increased with decrease in the pH of dye solution from 4 to 9. The isotherm data obtained from RB4 adsorption on CS and CS/HDA are adequately described by Freundlich model (R(2)=0.946 and 0.934, χ(2)=22.414 and 64.761). The kinetic study revealed that the pseudo-second-order rate model (R(2)=0.996 and 0.997) was in better agreement with the experimental data. The negative values of ΔG° (-2.28 and -6.30 kJ/mol) and ΔH° (-172.18 and -101.62 kJ/mol) for CS beads and HDA modified CS beads, respectively; suggested a spontaneous and exothermic process for RB4 adsorption. Copyright © 2015 Elsevier Ltd. All rights reserved.

Impact of Ficoll density gradient centrifugation on major and trace element concentrations in erythrocytes and blood plasma.

PubMed

Lu, Ying; Ahmed, Sultan; Harari, Florencia; Vahter, Marie

2015-01-01

Ficoll density gradient centrifugation is widely used to separate cellular components of human blood. We evaluated the suitability to use erythrocytes and blood plasma obtained from Ficoll centrifugation for assessment of elemental concentrations. We determined 22 elements (from Li to U) in erythrocytes and blood plasma separated by direct or Ficoll density gradient centrifugation, using inductively coupled plasma mass spectrometry. Compared with erythrocytes and blood plasma separated by direct centrifugation, those separated by Ficoll had highly elevated iodine and Ba concentration, due to the contamination from the Ficoll-Paque medium, and about twice as high concentrations of Sr and Mo in erythrocytes. On the other hand, the concentrations of Ca in erythrocytes and plasma were markedly reduced by the Ficoll separation, to some extent also Li, Co, Cu, and U. The reduced concentrations were probably due to EDTA, a chelator present in the Ficoll medium. Arsenic concentrations seemed to be lowered by Ficoll, probably in a species-specific manner. The concentrations of Mg, P, S, K, Fe, Zn, Se, Rb, and Cs were not affected in the erythrocytes, but decreased in plasma. Concentrations of Mn, Cd, and Pb were not affected in erythrocytes, but in plasma affected by EDTA and/or pre-analytical contamination. Ficoll separation changed the concentrations of Li, Ca, Co, Cu, As, Mo, I, Ba, and U in erythrocytes and blood plasma, Sr in erythrocytes, and Mg, P, S, K, Fe, Zn, Se, Rb and Cs in blood plasma, to an extent that will invalidate evaluation of deficiencies or excess intakes. Copyright © 2014 Elsevier GmbH. All rights reserved.

Pegmatite/wallrock interactions, Black Hills, South Dakota: Progressive boron metasomatism adjacent to the Tip Top pegmatite

NASA Astrophysics Data System (ADS)

Shearer, C. K.; Papike, J. J.; Simon, S. B.; Laul, J. C.; Christian, R. P.

1984-12-01

Interaction between country rock and fluids derived from the Tip Top pegmatite has resulted in a series of boron enriched assemblages. Between unaltered quartz-mica schist to the pegmatite contact is a succession of four mineral assemblages: (1) Quartz-Biotite-Potassium Feldspar assemblage (Q-B-K), which consists essentially of the original metamorphic silicate assemblage plus anomalously high amounts of modal tourmaline (2) Quartz-Biotite-Tourmaline assemblage (Q-B-T) (3) Tourmaline-Quartz-Muscovite assemblage (T-Q-M) (4) Tourmaline-Quartz assemblage (T-Q). Alkali elements (Cs, Rb, K, Li), SiO 2, and Ba show a decrease from the Q-B-K assemblage to the T-Q assemblage. A1 2O 3, Ga, B, total Fe and Zn increase moderately from the Q-B-K assemblage to the T-Q assemblage. The mineral chemistries also change considerably. The Mg/(Mg + Fe 2+) ratios in biotites range from 0.54 to 0.50 in samples from the Q-B-K assemblage to 0.39 in the (Q-B-T) assemblage. The range in tourmaline end-member components from the Q-B-K assemblage to the T-Q assemblage is as follows: Q-B-K: Dravite .63 Schorl .23 Elbaite .05 Buergerite .09 T-Q: Dravite .23 Schorl .37 Elbaite .17 Buergerite .23. Observed variations in mineral assemblage and whole rock chemistry within the alteration zone appear to a first approximation to be a function of μB2O3 (boron metasomatism) and μK2O (alkali leaching). The breakdown of feldspar and biotite may be approximated by reactions: 2HCl + 2(K, Na)AlSi 3O 8 /ai 2(K, Na)Cl + Al 2SiO 5 + 5SiO 2 + H 2O and 2 Annite + SiO 2 + 5Al 2SiO 5 + 2NaCl + 6H 3BO 3 /ai 2 Tourmaline + 2KCl + 7H 2O. The alteration zone may represent either a single episode (B-, Cs-, Li-, Rb-enriched fluid) or multiple episodes (B, Zn, Mn fluid and Cs, Li, Rb fluid) of pegmatite fluid-schist interactions. In both situations, B in the aqueous fluid from the pegmatite reacts with the schist breaking down sheet silicate "traps" for Cs, Rb, Li, and K and forming tourmaline-rich assemblages.

Pegmatite/wallrock interactions, Black Hills, South Dakota: Progressive boron metasomatism adjacent to the Tip Top pegmatite

USGS Publications Warehouse

Shearer, C.K.; Papike, J.J.; Simon, S.B.; Laul, J.C.; Christian, R.P.

1984-01-01

Interaction between country rock and fluids derived from the Tip Top pegmatite has resulted in a series of boron enriched assemblages. Between unaltered quartz-mica schist to the pegmatite contact is a succession of four mineral assemblages: 1. (1) Quartz-Biotite-Potassium Feldspar assemblage (Q-B-K), which consists essentially of the original metamorphic silicate assemblage plus anomalously high amounts of modal tourmaline 2. (2) Quartz-Biotite-Tourmaline assemblage (Q-B-T) 3. (3) Tourmaline-Quartz-Muscovite assemblage (T-Q-M) 4. (4) Tourmaline-Quartz assemblage (T-Q). Alkali elements (Cs, Rb, K, Li), SiO2, and Ba show a decrease from the Q-B-K assemblage to the T-Q assemblage. A12O3, Ga, B, total Fe and Zn increase moderately from the Q-B-K assemblage to the T-Q assemblage. The mineral chemistries also change considerably. The Mg/(Mg + Fe2+) ratios in biotites range from 0.54 to 0.50 in samples from the Q-B-K assemblage to 0.39 in the (Q-B-T) assemblage. The range in tourmaline end-member components from the Q-B-K assemblage to the T-Q assemblage is as follows: Q-B-K: Dravite.63 Schorl.23 Elbaite.05 Buergerite.09 T-Q: Dravite.23 Schorl.37 Elbaite.17 Buergerite.23. Observed variations in mineral assemblage and whole rock chemistry within the alteration zone appear to a first approximation to be a function of ??B2O3 (boron metasomatism) and ??K2O (alkali leaching). The breakdown of feldspar and biotite may be approximated by reactions: 2HCl + 2(K, Na)AlSi3O8 /ai 2(K, Na)Cl + Al2SiO5 + 5SiO2 + H2O and 2 Annite + SiO2 + 5Al2SiO5 + 2NaCl + 6H3BO3 /ai 2 Tourmaline + 2KCl + 7H2O. The alteration zone may represent either a single episode (B-, Cs-, Li-, Rb-enriched fluid) or multiple episodes (B, Zn, Mn fluid and Cs, Li, Rb fluid) of pegmatite fluid-schist interactions. In both situations, B in the aqueous fluid from the pegmatite reacts with the schist breaking down sheet silicate "traps" for Cs, Rb, Li, and K and forming tourmaline-rich assemblages. ?? 1984.

Dual species entanglement of Rb and Cs qubits with Rydberg blockade for crosstalk free qubit measurements

NASA Astrophysics Data System (ADS)

Baker, Kevin; Yu, Zhaoning; Ebert, Matthew; Sun, Yuan; Saffman, Mark

2016-05-01

One of the outstanding challenges facing neutral atom qubit approaches to quantum computation is suppression of crosstalk between proximal qubits due to scattered light that is generated during optical pumping and measurement operations. We have recently proposed a dual species approach to solving this challenge whereby computational qubits encoded in Cs atoms are entangled with Rb atoms via an interspecies Rydberg interaction. The quantum state of a Cs atom can then be readout by measuring the state of a Rb atom. The difference in resonant wavelengths of the two species effectively suppresses crosstalk. We will present progress towards experimental demonstration of dual species entanglement using Rb and Cs atoms cotrapped in a single beam optical trap. Work supported by the ARL CDQI.

Iron cycling at corroding carbon steel surfaces.

PubMed

Lee, Jason S; McBeth, Joyce M; Ray, Richard I; Little, Brenda J; Emerson, David

2013-01-01

Surfaces of carbon steel (CS) exposed to mixed cultures of iron-oxidizing bacteria (FeOB) and dissimilatory iron-reducing bacteria (FeRB) in seawater media under aerobic conditions were rougher than surfaces of CS exposed to pure cultures of either type of microorganism. The roughened surface, demonstrated by profilometry, is an indication of loss of metal from the surface. In the presence of CS, aerobically grown FeOB produced tight, twisted helical stalks encrusted with iron oxides. When CS was exposed anaerobically in the presence of FeRB, some surface oxides were removed. However, when the same FeOB and FeRB were grown together in an aerobic medium, FeOB stalks were less encrusted with iron oxides and appeared less tightly coiled. These observations suggest that iron oxides on the stalks were reduced and solubilized by the FeRB. Roughened surfaces of CS and denuded stalks were replicated with culture combinations of different species of FeOB and FeRB under three experimental conditions. Measurements of electrochemical polarization resistance established different rates of corrosion of CS in aerobic and anaerobic media, but could not differentiate rate differences between sterile controls and inoculated exposures for a given bulk concentration of dissolved oxygen. Similarly, total iron in the electrolyte could not be used to differentiate treatments. The experiments demonstrate the potential for iron cycling (oxidation and reduction) on corroding CS in aerobic seawater media.

Iron cycling at corroding carbon steel surfaces

PubMed Central

Lee, Jason S.; McBeth, Joyce M.; Ray, Richard I.; Little, Brenda J.; Emerson, David

2013-01-01

Surfaces of carbon steel (CS) exposed to mixed cultures of iron-oxidizing bacteria (FeOB) and dissimilatory iron-reducing bacteria (FeRB) in seawater media under aerobic conditions were rougher than surfaces of CS exposed to pure cultures of either type of microorganism. The roughened surface, demonstrated by profilometry, is an indication of loss of metal from the surface. In the presence of CS, aerobically grown FeOB produced tight, twisted helical stalks encrusted with iron oxides. When CS was exposed anaerobically in the presence of FeRB, some surface oxides were removed. However, when the same FeOB and FeRB were grown together in an aerobic medium, FeOB stalks were less encrusted with iron oxides and appeared less tightly coiled. These observations suggest that iron oxides on the stalks were reduced and solubilized by the FeRB. Roughened surfaces of CS and denuded stalks were replicated with three culture combinations of different species of FeOB and FeRB under three experimental conditions. Measurements of electrochemical polarization resistance established different rates of corrosion of CS in aerobic and anaerobic media, but could not differentiate rate differences between sterile controls and inoculated exposures for a given bulk concentration of dissolved oxygen. Similarly, total iron in the electrolyte could not be used to differentiate treatments. The experiments demonstrate the potential for iron cycling (oxidation and reduction) on corroding CS in aerobic seawater media. PMID:24093730

Chloride, bromide and iodide scintillators with europium

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

Zhuravleva, Mariya; Yang, Kan

A halide scintillator material is disclosed where the halide may comprise chloride, bromide or iodide. The material is single-crystalline and has a composition of the general formula ABX.sub.3 where A is an alkali, B is an alkali earth and X is a halide which general composition was investigated. In particular, crystals of the formula ACa.sub.1-yEu.sub.yI.sub.3 where A=K, Rb and Cs were formed as well as crystals of the formula CsA.sub.1-yEu.sub.yX.sub.3 (where A=Ca, Sr, Ba, or a combination thereof and X=Cl, Br or I or a combination thereof) with divalent Europium doping where 0.ltoreq.y.ltoreq.1, and more particularly Eu doping has beenmore » studied at one to ten mol %. The disclosed scintillator materials are suitable for making scintillation detectors used in applications such as medical imaging and homeland security.« less

Constituent elements and their distribution in the radioactive Cs-bearing silicate glass microparticles released from Fukushima nuclear plant.

PubMed

Kogure, Toshihiro; Yamaguchi, Noriko; Segawa, Hiroyo; Mukai, Hiroki; Motai, Satoko; Akiyama-Hasegawa, Kotone; Mitome, Masanori; Hara, Toru; Yaita, Tsuyoshi

2016-10-01

Microparticles of radioactive cesium (Cs)-bearing silicate glass emitted from the Fukushima Daiichi nuclear power plant were investigated mainly using state-of-the-art energy-dispersive X-ray spectroscopy in scanning transmission electron microscopes. Precise elemental maps of the particles were obtained using double silicon drift detectors with a large collection angle of X-rays, and qualitative elemental analysis was performed using high-resolution X-ray spectroscopy with a microcalorimetry detector. Beside the substantial elements (O, Si, Cl, K, Fe, Zn, Rb, Sn and Cs) as previously reported, Mn and Ba were also common, though their amounts were small. The atomic ratios of the substantial elements were not the same but varied among individual particles. Fe and Zn were relatively homogeneously distributed, whereas the concentration of alkali ions varied radially. Generally, Cs was rich and K and Rb were poor outward of the particles but the degree of such radial dependence was considerably different among the particles. A concentration of Sn on the particle surface was observed. High-resolution imaging indicated the formation of SnO 2 (cassiterite) nanocrystals on the surface. Synthesis of the bulk glass with a similar composition to the microparticles was attempted by quenching the silicate melt from ∼1600°C. However, homogeneous silicate glass like that of the microparticles could not be obtained due to the segregation of nano-spherules rich in Fe and Zn, suggesting that the microparticles were formed in a very specific condition in the nuclear reactor. © The Author 2016. Published by Oxford University Press on behalf of The Japanese Society of Microscopy. All rights reserved.For permissions, please e-mail: journals.permissions@oup.com.

Isotopic signature and nano-texture of cesium-rich micro-particles: Release of uranium and fission products from the Fukushima Daiichi Nuclear Power Plant.

PubMed

Imoto, Junpei; Ochiai, Asumi; Furuki, Genki; Suetake, Mizuki; Ikehara, Ryohei; Horie, Kenji; Takehara, Mami; Yamasaki, Shinya; Nanba, Kenji; Ohnuki, Toshihiko; Law, Gareth T W; Grambow, Bernd; Ewing, Rodney C; Utsunomiya, Satoshi

2017-07-14

Highly radioactive cesium-rich microparticles (CsMPs) released from the Fukushima Daiichi Nuclear Power Plant (FDNPP) provide nano-scale chemical fingerprints of the 2011 tragedy. U, Cs, Ba, Rb, K, and Ca isotopic ratios were determined on three CsMPs (3.79-780 Bq) collected within ~10 km from the FDNPP to determine the CsMPs' origin and mechanism of formation. Apart from crystalline Fe-pollucite, CsFeSi 2 O 6  · nH 2 O, CsMPs are comprised mainly of Zn-Fe-oxide nanoparticles in a SiO 2 glass matrix (up to ~30 wt% of Cs and ~1 wt% of U mainly associated with Zn-Fe-oxide). The 235 U/ 238 U values in two CsMPs: 0.030 (±0.005) and 0.029 (±0.003), are consistent with that of enriched nuclear fuel. The values are higher than the average burnup estimated by the ORIGEN code and lower than non-irradiated fuel, suggesting non-uniform volatilization of U from melted fuels with different levels of burnup, followed by sorption onto Zn-Fe-oxides. The nano-scale texture and isotopic analyses provide a partial record of the chemical reactions that occurred in the fuel during meltdown. Also, the CsMPs were an important medium of transport for the released radionuclides in a respirable form.

Pressure-Induced Amorphization of Small Pore Zeolites—the Role of Cation-H2O Topology and Anti-glass Formation

PubMed Central

Chan Hwang, Gil; Joo Shin, Tae; Blom, Douglas A.; Vogt, Thomas; Lee, Yongjae

2015-01-01

Systematic studies of pressure-induced amorphization of natrolites (PIA) containing monovalent extra-framework cations (EFC) Li+, Na+, K+, Rb+, Cs+ allow us to assess the role of two different EFC-H2O configurations within the pores of a zeolite: one arrangement has H2O molecules (NATI) and the other the EFC (NATII) in closer proximity to the aluminosilicate framework. We show that NATI materials have a lower onset pressure of PIA than the NATII materials containing Rb and Cs as EFC. The onset pressure of amorphization (PA) of NATII materials increases linearly with the size of the EFC, whereas their initial bulk moduli (P1 phase) decrease linearly. Only Cs- and Rb-NAT reveal a phase separation into a dense form (P2 phase) under pressure. High-Angle Annular Dark Field Scanning Transmission Electron Microscopy (HAADF-STEM) imaging shows that after recovery from pressures near 25 and 20 GPa long-range ordered Rb-Rb and Cs-Cs correlations continue to be present over length scales up to 100 nm while short-range ordering of the aluminosilicate framework is significantly reduced—this opens a new way to form anti-glass structures. PMID:26455345

Pressure-Induced Amorphization of Small Pore Zeolites-the Role of Cation-H2O Topology and Anti-glass Formation.

PubMed

Chan Hwang, Gil; Joo Shin, Tae; Blom, Douglas A; Vogt, Thomas; Lee, Yongjae

2015-10-12

Systematic studies of pressure-induced amorphization of natrolites (PIA) containing monovalent extra-framework cations (EFC) Li(+), Na(+), K(+), Rb(+), Cs(+) allow us to assess the role of two different EFC-H2O configurations within the pores of a zeolite: one arrangement has H2O molecules (NATI) and the other the EFC (NATII) in closer proximity to the aluminosilicate framework. We show that NATI materials have a lower onset pressure of PIA than the NATII materials containing Rb and Cs as EFC. The onset pressure of amorphization (PA) of NATII materials increases linearly with the size of the EFC, whereas their initial bulk moduli (P1 phase) decrease linearly. Only Cs- and Rb-NAT reveal a phase separation into a dense form (P2 phase) under pressure. High-Angle Annular Dark Field Scanning Transmission Electron Microscopy (HAADF-STEM) imaging shows that after recovery from pressures near 25 and 20 GPa long-range ordered Rb-Rb and Cs-Cs correlations continue to be present over length scales up to 100 nm while short-range ordering of the aluminosilicate framework is significantly reduced-this opens a new way to form anti-glass structures.

Crystal Structure and Thermoelectric Properties of β-Pyrochlore-Type Alkali Iron Tungsten Oxides with Cage-Like Structure

NASA Astrophysics Data System (ADS)

Mizuta, Kohei; Ohtaki, Michitaka

2016-03-01

We report the electrical and thermal properties of β-pyrochlore (defect pyrochlore) oxides AFe0.33W1.67O6 ( A = K, Rb, Cs) with a crystal structure having a small cation surrounded by oversized cage-like framework. The thermal conductivity, κ, of CsFe0.33W1.67O6 and RbFe0.33W1.67O6 showed extremely low values as oxides (below 1.0 W/mK) similar to those of ATaWO6 ( A = K, Rb, Cs) which we have already reported. These low κ values are ascribed to a "rattling" motion of the A cations, evidenced by their crystal structure refinement and the Raman spectra. Their electrical conductivity, σ, was in the order of 10-3 S/cm, and the Seebeck coefficient, S, was -500 to -600 μV/K. The electrical conductivity of AFe0.33W1.67O6 ( A = Rb, Cs) was much higher than those of ATaWO6 ( A = Rb, Cs), suggesting that an appropriate selection of the framework composition enables us to have better thermoelectric performance.

Photoassociation of cold (RbCs)2 tetramers in the ground electronic state

NASA Astrophysics Data System (ADS)

Gacesa, Marko; Côté, Robin

2017-04-01

We theoretically investigate prospects for photoassociative formation of cold (RbCs)2 tetramers from a pair of ultracold RbCs molecules. The long-range region of the potential energy surface (PES) of the lowest electronic state of (RbCs)2 can be affected by orienting both RbCs molecules by an external electric field. In fact, we find a long-range barrier that supports long-range shelf states for relative angles between the dimers' internuclear axes smaller than about 20°. We show that these shelf states can be populated by spontaneous decay from the first excited electronic state which can be efficiently populated by photoassociation from the scattering continuum at ultracold temperatures. The vibrationally excited ground-state tetramer molecules formed this way have sufficiently long lifetimes to allow experimental detection. Moreover, for the relative angles between the dimers close to 20°, the proposed approach may result in production of deeply bound tetramers. Partially supported by the NASA Postdoctoral Program at the NASA Ames Research Center, administered by USRA and the MURI US Army Research Office Grant No. W911NF-14-1-0378 (MG), and by the PIF program of the National Science Foundation Grant No. PHY-141556.

Influence of Rb/Cs Cation-Exchange on Inorganic Sn Halide Perovskites: From Chemical Structure to Physical Properties.

PubMed

Jung, Young-Kwang; Lee, Ji-Hwan; Walsh, Aron; Soon, Aloysius

2017-04-11

CsSnI 3 is a potential lead-free inorganic perovskite for solar energy applications due to its nontoxicity and attractive optoelectronic properties. Despite these advantages, photovoltaic cells using CsSnI 3 have not been successful to date, in part due to low stability. We demonstrate how gradual substitution of Rb for Cs influences the structural, thermodynamic, and electronic properties on the basis of first-principles density functional theory calculations. By examining the effect of the Rb:Cs ratio, we reveal a correlation between octahedral distortion and band gap, including spin-orbit coupling. We further highlight the cation-induced variation of the ionization potential (work function) and the importance of surface termination for tin-based halide perovskites for engineering high-performance solar cells.

An adiabatic spectroscopic investigation of the CsRb system in ground and numerous excited states

NASA Astrophysics Data System (ADS)

Souissi, Hanen; Jellali, Soulef; Maha, Chaieb; Habli, Héla; Oujia, Brahim; Gadéa, Florent Xavier

2017-10-01

Via ab-initio approximations, we investigate the electronic and structural features of the CsRb molecule. Adiabatic potential energy curves of 261,3Σ+, 181,3Π and 61,3Δ electronic states with their derived spectroscopic constants as well as vibrational levels spacing have been carried out and well explained. Our approach is founded on an Effective Core Potential (ECP) describing the valence electrons of the system. Using a large Gaussian basis set, the full valence Configuration Interaction can be applied easily on the two-effective valence electrons of the CsRb system. Furthermore, a detailed analysis of the electric dipolar properties has been made through the investigation of both permanent and transition dipole moments (PDM and TDM). It is significant that the ionic character connected with electron transfer that is linked to Cs+ Rb- state has been clearly illustrated in the adiabatic permanent dipole moment.

Hyperfine frequencies of {sup 87}Rb and {sup 133}Cs atoms in Xe gas

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

McGuyer, B. H.; Xia, T.; Jau, Y.-Y.

2011-09-15

The microwave resonant frequencies of ground-state {sup 87}Rb and {sup 133}Cs atoms in Xe buffer gas are shown to have a relatively large nonlinear dependence on the Xe pressure, presumably because of RbXe or CsXe van der Waals molecules. The nonlinear shifts for Xe are opposite in sign to the previously measured shifts for Ar and Kr, even though all three gases have negative linear shifts. The Xe data show striking discrepancies with the previous theory for nonlinear shifts. Most of this discrepancy is eliminated by accounting for the spin-rotation interaction, {gamma}N{center_dot}S, in addition to the hyperfine-shift interaction, {delta} Amore » I{center_dot}S, in the molecules. To the limit of our experimental accuracy, the shifts of {sup 87}Rb and {sup 133}Cs in He, Ne, and N{sub 2} were linear with pressure.« less

Trace element partitioning between coexisting biotite and muscovite from metamorphic rocks, western Labrador: Structural, compositional and thermal controls

NASA Astrophysics Data System (ADS)

Yang, Panseok; Rivers, Toby

2000-04-01

Coexisting biotite and muscovite in ten metapelitic and quartzofeldspathic rocks from western Labrador have been analyzed by electron microprobe for major and minor elements and by a laser ablation microprobe coupled to ICP-MS (LAM-ICP-MS) for selected trace elements - Li, Sc, V, Cr, Mn, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Cs, Ba, REE, Hf and Ta. The samples have experienced a single prograde Grenvillian metamorphism ranging from 490 to 680°C and from 7 to 12 kbar. The trace element compositions of coexisting micas in the metamorphic rocks are used to assess the effects of crystal structure, major element composition and temperature on the partitioning of each element between biotite and muscovite. Overall, trace element distributions are systematic across the range of metamorphic grade and bulk composition, suggesting that chemical equilibrium was approached. Most distribution coefficients (biotite/muscovite) show good agreement with published data. However, distribution coefficients for Co and Sr are significantly different from previous determinations, probably because of contamination associated with older data obtained by bulk analysis techniques. The sequence of distribution coefficients is governed mainly by the ionic radii and charges of substituting cations compared to the optimum ionic radius of each crystallographic site in the micas. In particular, distribution coefficients exhibit the sequence Cr 3+ (0.615 Å) > V 3+ (0.64 Å) > Sc 3+ (0.745 Å) in VI-sites, and Ba 2+ (1.61 Å) > Sr 2+ (1.44 Å) and Cs + (1.88 Å) > K + (1.64 Å) > Rb + (1.72 Å) > Na + (1.39 Å) in XII-sites. The distributions of Li, Sc, Sr and Ba appear to be thermally sensitive but are also controlled by major element compositions of micas. V and Zr partitioning is dependent on T and may be used to cross-check thermometry calculations where the latter suffer from retrograde re-equilibration and/or high concentrations of Fe 3+. The ranges and dependence of distribution coefficients on major element compositions provide important constraints on the values that can be used in geochemical modeling.

Development of the chromatographic partitioning of cesium and strontium utilizing two macroporous silica-based calix[4]arene-crown and amide impregnated polymeric composites: PREC partitioning process.

PubMed

Zhang, Anyun; Kuraoka, Etsushu; Kumagai, Mikio

2007-07-20

To partition effectively Cs(I) and Sr(II), two harmful heat emitting nuclides, from a highly active liquid waste by extraction chromatography, two kinds of macroporous silica-based polymeric materials, Calix[4]arene-R14/SiO(2)-P and TODGA/SiO(2)-P, were synthesized. Two chelating agents, 1,3-[(2,4-diethyl-heptylethoxy)oxy]-2,4-crown-6-calix[4]arene (Calix[4]arene-R14), an excellent supramolecular compound having molecular recognition ability for Cs(I), and N,N,N',N'-tetraoctyl-3-oxapentane-1,5-diamide (TODGA) were impregnated and immobilized into the pores of SiO(2)-P particles support by a vacuum sucking technique. The loading and elution of 11 typical simulated fission and non-fission products from 4.0M or 2.0M HNO(3) were performed at 298K. It was found that in the first column packed with the Calix[4]arene-R14/SiO(2)-P, all of the simulated elements were separated effectively into two groups: (1) Na(I), K(I), Sr(II), Fe(III), Ba(II), Ru(III), Pd(II), Zr(IV), and Mo(VI) (noted as Sr-group); (2) Cs(I)-Rb(I) (Cs-group) by eluting with 4.0M HNO(3) and distilled water, respectively. The harmful element Cs(I) flowed into the second group along with Rb(I) because of their close sorption and elution properties towards Calix[4]arene-R14/SiO(2)-P, while Sr(II) showed no sorption and flowed into Sr-containing group. In the second column packed with TODGA/SiO(2)-P, the Sr-group was separated into (1) Ba(II), Ru(III), Na(I), K(I), Fe(III), and Mo(VI) (non-sorption group); (2) Sr(II); (3) Pd(II); and (4) Zr(IV) by eluting with 2.0M HNO(3), 0.01M HNO(3), 0.05M DTPA-pH 2.5, and 0.5M H(2)C(2)O(4), respectively. Sr(II) adsorbed towards TODGA/SiO(2)-P flowed into the second group and showed the excellent separation efficiency from others. Based on the elution behavior of the tested elements, an advanced PREC (Partitioning and Recovery of two heat generators from an acidic HLW (high activity liquid waste) by Extraction Chromatography) process was proposed.

Production of complex rubidium and cesium hydrogen sulfate‒phosphates

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

Komornikov, V. A., E-mail: v.a.kom@mail.ru; Grebenev, V. V.; Makarova, I. P.

2016-07-15

The solubility in the CsH{sub 2}PO{sub 4}‒CsHSO{sub 4}‒H{sub 2}O system at different temperatures (25, 50, and 75°C) is studied and the phase equilibria in the Rb{sub 3}H(SO{sub 4}){sub 2}‒RbH{sub 2}PO{sub 4}‒H{sub 2}O system under isothermal conditions (at 25°C) are analyzed. The temperature and concentration conditions for forming Rb{sub 2}(HSO{sub 4})(H{sub 2}PO{sub 4}), Rb{sub 4}(HSO{sub 4}){sub 3}(H{sub 2}PO{sub 4}), Cs{sub 4}(HSO{sub 4}){sub 3}(H{sub 2}PO{sub 4}), Cs{sub 3}(HSO{sub 4}){sub 2}(H{sub 2}PO{sub 4}), Cs{sub 2}(HSO{sub 4})(H{sub 2}PO{sub 4}), and Cs{sub 6}H(HSO{sub 4}){sub 3}(H{sub 2}PO{sub 4}){sub 4} compounds (the latter has been obtained for the first time) are determined. The conditions for growing largemore » single crystals of complex acid rubidium and cesium salts are found.« less

Cs-Ba separation using N 2O as a reactant gas in a Multiple Collector-Inductively Coupled Plasma Mass Spectrometer collision-reaction cell: Application to the measurements of Cs isotopes in spent nuclear fuel samples

NASA Astrophysics Data System (ADS)

Granet, M.; Nonell, A.; Favre, G.; Chartier, F.; Isnard, H.; Moureau, J.; Caussignac, C.; Tran, B.

2008-11-01

In the general frameworks of the nuclear fuel cycle and environmental research field, the Cs isotopic composition must be known with high precision and accuracy. The direct determination of Cs isotopes by mass spectrometry techniques is generally hampered by the presence of Ba isobaric interferences however. Here we present a new method which takes advantage of the collision-reaction cell based Multiple Collector Inductively Coupled Plasma Mass Spectrometry (MC-ICPMS) and allows to analyse Cs isotopes in the presence of Ba without prior separation step. The addition of N 2O gas in the cell leads to an antagonistic behavior of Cs + and Ba + as the latter reacts with the gas to form BaO + and BaOH + products whereas Cs + remains unreactive. The efficiency of the method was demonstrated for an UOx sample by comparing the results obtained (1) from the measurements of pure Cs fractions and (2) from Fission Products fractions containing more than 30 ionisable elements in addition to Cs, Ba, and where U and Pu were previously removed by using ion exchange resin. An excellent agreement is achieved between each set of experiments with an external reproducibility always better than 0.5% (RSD, k = 2). This study confirms the strong potential of collision-reaction cell to measure Cs isotopes in presence of interfering Ba, precluding therefore former systematic chemical separations.

The Natural Enrichment of Stable Cesium in Weathered Micaceous Materials and Its Implications for 137Cs Sorption.

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

Elliott, W. Crawford; Kahn, Bernd; Rosson, Robert

2011-11-14

In this exploratory project, we are testing two interrelated hypotheses about the sorption of Cs within weathered micaceous materials in subsurface regolith materials from the Savannah River Site (SRS) located on the Atlantic Coastal Plain: 1) that stable cesium has become significantly enriched relative to potassium in subsurface micaceous particles as a result of chemical weathering processes; and 2) that the Cs so present is sufficient to be a major factor determining the ability of the subsurface materials to take up and hold 137Cs. To test these hypotheses, we collected by hand augur soil samples corresponding to soils representative atmore » the SRS: upland regolith (Fuquay series); soils formed on Tobacco Road Sandstone; and, soils formed on Quaternary Alluvium. From our data, the quantification of the amounts of stable cesium concentrated in various sites within 2:1 phyllosilicates by natural processes is highly relevant toward understanding the future sorption of 137Cs by the mica, illite, vermiculite, and hydroxyl interstratified vermiculite (HIV) phases present in the subsurface at and in proximity to SRS. Studying sorption and fixation of Cs in these micaceous phases interlayers potentially leads to increased knowledge to the extent that stable Cs resists exchange with ion exchange cations (Mg, NH4, or even alkyl ammonium compounds) and to the extent that Cs can become fixed over the long term. Such knowledge will help in the development of 137Cs remediation strategies for the long-term, which is a critical aspect of the SBR goals. We characterized the mineralogy, K-Ar ages of the soil and soil clay fractions (before and after acid treatment), and alkali element chemistry (K, Rb, Cs) of the clay fractions of soils collected from these three different types of soils. The clay fractions of the Fuquay soils are composed of kaolinite, and hydroxy interstratified vermiculite (HIV). Kaolinite, HIV, quartz, gibbsite and illite are found in the quaternary soils. Leach experiments using 10% nitric acid and 50% nitric acid were performed on 62 mesh fractions to show the amounts of Cs and Rb relative to K (Cs/K, Rb/K) that are exchangeable in these soils compared to Coastal Plain micas and upper continental crust. The Cs/K and Rb/K of the leachates are considerably higher relative to both upper continental crust and relative to weathered micas found in Georgia Coast Plain sediments. The K-Ar ages of the clay fractions of five different SRS soil series were ca. 320 Ma. After leaching with nitric acid, the ages of the soil clay fractions were approximately the same as the unleached soil clays. Based on the similarity of these ages to the ages of Coastal Plain micas, the K and Ar remaining after treatment is believed to be enclosed in a relect mica in the HIV phases in the soils. The HIV is likely a mica-HIV intergrade. Based on these data, stable cesium has become significantly enriched relative to potassium in subsurface micaceous particles as a result of chemical weathering processes in the SRS Fuquay soils studied thus far. Our data permit the interpretation describing the sorption of Cs and Rb in an apex site or in a hard to reach hard-to-exchange sorption site during pedogenesis. In terms of testing the second hypothesis, our work is ongoing and we report some preliminary data on Cs-137 and Rb-85 exchange experiments on select SRS Fuquay soils (-2 mm). Our isotopic equilibration experiments using Cs and Rb isotopes in separate exchange experiments show only small amounts of Cs and Rb in the original sample is exchangeable isotopically for a period of a few weeks in acidified conditions. The isotope exchange experiments provide support for our interpretation that pedogenically accumulated Cs (and Rb) occupy sites that are unavailable to exchange or exchange slowly in acid conditions corresponding to present conditions in SRS soils. In more basic solutions, greater exchange isotopic exchange is noted and suggests an expansion of interlayer sites thereby permitting more isotopic exchange of Cs and Rb.« less

Postsynthesis Phase Transformation for CsPbBr3/Rb4PbBr6 Core/shell Nanocrystals with Exceptional Photostability.

PubMed

Wang, Bo; Zhang, Congyang; Huang, Shouqiang; Li, Zhichun; Kong, Long; Jin, Ling; Wang, Junhui; Wu, Kaifeng; Li, Liang

2018-06-15

Lead halide perovskite nanocrystals (NCs) as promising optoelectronic materials are intensively researched. However, the instability is one of the biggest challenges needed to overcome before fulfill their practical applications. To improve their stability, we present a postsynthetic controlled phase transformation of CsPbBr3 toward CsPbBr3/Rb4PbBr6 core/shell structure triggered by rubidium oleate treatment. The resulted core/shell NCs show exceptional photostability both in solution and on-chip. The solution of CsPbBr3/Rb4PbBr6 NCs can remain over 90% of the initial emission photoluminescence quantum yields (PLQY) after 42 h of intense light-emitting diodes illumination (450 nm, 175 mW/cm2), which is even better than the conventional CdSe/CdS quantum dots whose emission drop to 50% after 18 h under the same condition. We believe that the exceptional photostability should be resulted from the protection of the robust Rb4PbBr6 shell on CsPbBr3 NCs.

Determination of 30 elements in coal and fly ash by thermal and epithermal neutron-activation analysis

USGS Publications Warehouse

Rowe, J.J.; Steinnes, E.

1977-01-01

Thirty elements are determined in coal and fly ash by instrumental neutron-activation analysis using both thermal and epithermal irradiation. Gamma-ray spectra were recorded 7 and 20 days after the irradiations. The procedure is applicable to the routine analysis of coals and fly ash. Epithermal irradiation was found preferable for the determination of Ni, Zn, As, Se, Br, Rb, Sr, Mo, Sb, Cs, Ba, Sm, Tb, Hf, Ta, W, Th and U, whereas thermal irradiation was best for Sc, Cr, Fe, Co, La, Ce, Nd, Eu, Yb and Lu. Results for SRM 1632 (coal) and SRM 1633 (fly ash) agree with those of other investigators. ?? 1977.

Role of Acentric Displacements on the Crystal Structure and Second-Harmonic Generating Properties of RbPbCO3F and CsPbCO3F

PubMed Central

2015-01-01

Two lead fluorocarbonates, RbPbCO3F and CsPbCO3F, were synthesized and characterized. The materials were synthesized through solvothermal and conventional solid-state techniques. RbPbCO3F and CsPbCO3F were structurally characterized by single-crystal X-ray diffraction and exhibit three-dimensional (3D) crystal structures consisting of corner-shared PbO6F2 polyhedra. For RbPbCO3F, infrared and ultraviolet–visible spectroscopy and thermogravimetric and differential thermal analysis measurements were performed. RbPbCO3F is a new noncentrosymmetric material and crystallizes in the achiral and nonpolar space group P6̅m2 (crystal class 6̅m2). Powder second-harmonic generation (SHG) measurements on RbPbCO3F and CsPbCO3F using 1064 nm radiation revealed an SHG efficiency of approximately 250 and 300 × α-SiO2, respectively. Charge constants d33 of approximately 72 and 94 pm/V were obtained for RbPbCO3F and CsPbCO3F, respectively, through converse piezoelectric measurements. Electronic structure calculations indicate that the nonlinear optical response originates from the distorted PbO6F2 polyhedra, because of the even–odd parity mixing of the O 2p states with the nearly spherically symmetric 6s electrons of Pb2+. The degree of inversion symmetry breaking is quantified using a mode-polarization vector analysis and is correlated with cation size mismatch, from which it is possible to deduce the acentric properties of 3D alkali-metal fluorocarbonates. PMID:24867361

The role of the seagrass Posidonia oceanica in the cycling of trace elements

NASA Astrophysics Data System (ADS)

Sanz-Lázaro, C.; Malea, P.; Apostolaki, E. T.; Kalantzi, I.; Marín, A.; Karakassis, I.

2012-03-01

The aim of this work was to study the role of the seagrass Posidonia oceanica on the cycling of a wide set of trace elements (Ag, As, Ba, Bi, Cd, Co, Cr, Cs, Cu, Fe, Ga, Li, Mn, Ni, Pb, Rb, Sr, Tl, V and Zn). We measured the concentration of these trace elements in the different compartments of P. oceanica (leaves, rhizomes, roots and epibiota) in a non-polluted seagrass meadow representative of the Mediterranean and calculated the annual budget from a mass balance. We provide novel data on accumulation dynamics of many trace elements in P. oceanica compartments and demonstrate that trace element accumulation patterns are mainly determined by plant compartment rather than by temporal variability. Epibiota was the compartment which showed the greatest concentrations for most trace elements. Thus, they constitute a key compartment when estimating trace element transfer to higher trophic levels by P. oceanica. For most trace elements, translocation seemed to be low and acropetal. Zn, Cd, Sr and Rb were the trace elements that showed the highest release rate through decomposition of plant detritus, while Cs, Tl and Bi the lowest. P. oceanica acts as a sink of potentially toxic trace elements (Ni, Cr, As and Ag), which can be sequestered, decreasing their bioavailability. P. oceanica may have a relevant role in the cycling of trace elements in the Mediterranean.

The role of the seagrass Posidonia oceanica in the cycling of trace elements

NASA Astrophysics Data System (ADS)

Sanz-Lázaro, C.; Malea, P.; Apostolaki, E. T.; Kalantzi, I.; Marín, A.; Karakassis, I.

2012-07-01

The aim of this study was to investigate the role of the seagrass Posidonia oceanica on the cycling of a wide set of trace elements (Ag, As, Ba, Bi, Cd, Co, Cr, Cs, Cu, Fe, Ga, Li, Mn, Ni, Pb, Rb, Sr, Tl, V and Zn). We measured the concentration of these trace elements in different compartments of P. oceanica (leaves, rhizomes, roots and epiphytes) in a non-polluted seagrass meadow representative of the Mediterranean and calculated the annual budget from a mass balance. We provide novel data on accumulation dynamics of many trace elements in P. oceanica compartments and demonstrate that trace element accumulation patterns are mainly determined by plant compartment rather than by temporal variability. Epiphytes were the compartment, which showed the greatest concentrations for most trace elements. Thus, they constitute a key compartment when estimating trace element transfer to higher trophic levels by P. oceanica. Trace element translocation in P. oceanica seemed to be low and acropetal in most cases. Zn, Cd, Sr and Rb were the trace elements that showed the highest release rate through decomposition of plant detritus, while Cs, Tl and Bi showed the lowest. P. oceanica acts as a sink of potentially toxic trace elements (Ni, Cr, As and Ag), which can be sequestered, decreasing their bioavailability. P. oceanica may have a relevant role in the cycling of trace elements in the Mediterranean.

Marine geochemical cycles of the alkali elements and boron: the role of sediments

NASA Astrophysics Data System (ADS)

James, Rachael H.; Palmer, Martin R.

2000-09-01

We have analysed the concentrations of Li, K, Rb, Cs, and B, and the isotopic ratios of Li and B of a suite of pore fluids recovered from ODP Sites 1037 (Leg 169; Escanaba Trough) and 1034 (Leg 169S; Saanich Inlet). In addition, we have analysed dissolved K, Rb, and Cs concentrations for estuarine mixing of the Ganges-Brahmaputra river system. Together, these data sets have been used to assess the role of sediments in the marine geochemical cycles of the alkali elements and boron. Uptake onto clay minerals during estuarine mixing removes 20-30% of the riverine input of dissolved Cs and Rb to the oceans. Prior to this study, the only other recognised sink of Rb and Cs was uptake during low-temperature alteration of the oceanic crust. Even with this additional sink there is an excess of inputs over outputs in their modern oceanic mass balance. Pore fluid data show that Li and Rb are transferred into marine sediments during early diagenesis. However, modeling of the Li isotope systematics of the pore fluids from Site 1037 shows that seawater Li taken up during marine sedimentation can be readily returned to solution in the presence of less hydrated cations, such as NH 4+. This process also appears to result in high concentrations of pore fluid Cs (relative to local seawater) due to expulsion of adsorbed Cs from cation exchange sites. Flux calculations based on pore fluid data for a series of ODP sites indicate that early diagenesis of clay sediments removes around 8% of the modern riverine input of dissolved Li. Although NH 4+-rich fluids do result in a flux of Cs to the oceans, on the global scale this input only augments the modern riverine Cs flux by ˜3%. Nevertheless, this may have implications for the fate of radioactive Cs in the natural environment and waste repositories.

Phengite-hosted LILE enrichment in eclogite and related rocks: Implications for fluid-mediated mass transfer in subduction zones and arc magma genesis

USGS Publications Warehouse

Sorensen, Sorena S.; Grossman, J.N.; Perfit, M.R.

1997-01-01

Geochemical differences between island arc basalts (LAB) and ocean-floor basalts (mid-ocean ridge basalts; MORB) suggest that the large-ion lithophile elements (LILE) K, Ba, Rb and Cs are probably mobilized in subduction zone fluids and melts. This study documents LILE enrichment of eclogite, amphibolite, and epidote ?? garnet blueschist tectonic blocks and related rocks from melanges of two subduction complexes. The samples are from six localities of the Franciscan Complex, California, and related terranes of Oregon and Baja California, and from the Samana Metamorphic Complex, Samana Peninsula, Dominican Republic. Most Franciscan blocks are MORB-like in their contents of rare earth elements (REE) and high field strength elements (HFSE); in contrast, most Samana blocks show an LAB signature of these elements. The whole-rock K2O contents of both groups range from 1 to 3 wt %; K, Ba, Rb, and Cs are all strongly intercorrelated. Many blocks display K/Ba similar to melasomatized transition zones and rinds at their outer margins. Some transition zones and rinds are enriched in LILE compared with host blocks; others are relatively depleted in these elements. Some LILE-rich blocks contain 'early' coarse-grained muscovite that is aligned in the foliation defined by coarse-grained omphacite or amphibole grains. Others display 'late' muscovite in veins and as a partial replacement of garnet; many contain both textural types. The muscovite is phengite that contains ???3??25-3??55 Si per 11 oxygens, and ???0??25-0??50 Mgper 11 oxygens. Lower-Si phengite has a significant paragonite component: Na per 11 oxygens ranges to ???0??12. Ba contents of phengite range to over 1 wt % (0??027 per 11 oxygens). Ba in phengite does not covary strongly with either Na or K. Ba contents of phengite increase from some blocks to their transition zones or rinds, or from blocks to their veins. Averaged KlBa ratios for phengite and host samples define an array which describes other subsamples of the block and other analyzed blocks. Phengite carries essentially all of the LILE in otherwise mafic eclogite, amphibolite, and garnet blueschist blocks that are enriched in these elements compared with MORE. It evidently tracks a distinctive type of LILE metasomatism that attends both high-T and retrograde subduction zone metamorphism. An obvious source for the LILE is a fluid in equilibrium with metasedimentary rocks. High-grade semipelitic schists from subduction complexes and subductable sediment display LILE values that resemble those seen in the most LILE-rich blocks. Modeling of Ba and Ti suggests that 1-40 wt % of phengite added to MORB can produce their observed LILE enrichment. Thus, the release of LILE from such rocks to fluids or melts in very high-T and -P parts of subduction zones probably depends critically on the stability and solubility relations of phengite, which is thought to be stable at pressures as high as 95-110 kbar at T= 750-1050??C.

Spatial Variations and Sources of Trace Elements in Recent Snow from Glaciers at the Tibetan Plateau

NASA Astrophysics Data System (ADS)

Huang, J.; Li, Y.; Li, Z.; Cozzi, G.; Turetta, C.; Barbante, C.; Xiong, L.

2017-12-01

Various trace element (TEs) could be long-range transported through the atmosphere and deposited onto the snow surface. Recently, with the development of economy of China and the surrounding countries, TEs such as Pb, Cd, Mo and Sb in several glaciers from the Tibetan Plateau (TP) have been gradually affected by anthropogenic activities. This study presents the acid leached concentrations of TEs (e.g., Al, As, Ba, Co, Cr, Cs, Cu, Fe, Li, Mn, Mo, Pb, Rb, Sb, Sr, Ti, Tl, U, V) and dust content sampled from Qiumianleike (QMLK), Meikuang (MK), Yuzhufeng (YZF), Xiaodongkemadi (XDKMD), Gurenhekou (GRHK) glaciers on the TP from April to May of 2013. The different concentrations of TEs in the surface snow and snow pit samples over the five glaciers show that TEs were influenced both by surrounding environment of glaciers and seasonal variations of atmospheric impurity loading. Comparison of TEs concentrations with data of other sites, elevated concentrations of As, Cu, Mo, Pb and Sb were observed in glaciers of TP, showing significant atmospheric TEs pollution. Enrichment factor(EF) analysis indicates that Rb, V, U, Cr, Ba, Cs, Li, As, Co, Mn, Tl, Sr and Cu mainly originated from crustal dust, while anthropogenic inputs such as nonferrous metals melting, coal combustion and traffic emission made an important contribution to the Mo, Pb and Sb. Evidences from air mass back trajectories show the air masses arrived at QMLK mostly came from the Taklimakan desert, the TEs from the Taklimakan desert and the western TP could be transported to the MK and YZF glaciers . The air masses derived from the western TP and the southwestern TP affected the environment of the XDKMD and GRHK glaciers. Futhermore, the air masses passed through some big cities with developed industry and large population such as Urumqi, Bishkek, Dushanbe and some countries such as Pakistan and India could also bring pollutants to the studied glaciers.

Chloride, bromide and iodide scintillators with europium doping

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

Zhuravleva, Mariya; Yang, Kan

A halide scintillator material is disclosed where the halide may comprise chloride, bromide or iodide. The material is single-crystalline and has a composition of the general formula ABX.sub.3 where A is an alkali, B is an alkali earth and X is a halide which general composition was investigated. In particular, crystals of the formula ACa.sub.1-yEu.sub.yI.sub.3 where A=K, Rb and Cs were formed as well as crystals of the formula CsA.sub.1-yEu.sub.yX.sub.3 (where A=Ca, Sr, Ba, or a combination thereof and X=Cl, Br or I or a combination thereof) with divalent Europium doping where 0.ltoreq.y.ltoreq.1, and more particularly Eu doping has beenmore » studied at one to ten mol %. The disclosed scintillator materials are suitable for making scintillation detectors used in applications such as medical imaging and homeland security.« less

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

McCall, Kyle M.; Stoumpos, Constantinos C.; Kostina, Svetlana S.

The optical and electronic properties of Bridgman grown single crystals of the wide-bandgap semiconducting defect halide perovskites A3M2I9 (A = Cs, Rb; M = Bi, Sb) have been investigated. Intense Raman scattering was observed at room temperature for each compound, indicating high polarizability and strong electron–phonon coupling. Both low-temperature and room-temperature photoluminescence (PL) were measured for each compound. Cs3Sb2I9 and Rb3Sb2I9 have broad PL emission bands between 1.75 and 2.05 eV with peaks at 1.96 and 1.92 eV, respectively. The Cs3Bi2I9 PL spectra showed broad emission consisting of several overlapping bands in the 1.65–2.2 eV range. Evidence of strong electron–phononmore » coupling comparable to that of the alkali halides was observed in phonon broadening of the PL emission. Effective phonon energies obtained from temperature-dependent PL measurements were in agreement with the Raman peak energies. A model is proposed whereby electron–phonon interactions in Cs3Sb2I9, Rb3Sb2I9, and Cs3Bi2I9 induce small polarons, resulting in trapping of excitons by the lattice. The recombination of these self-trapped excitons is responsible for the broad PL emission. Rb3Bi2I9, Rb3Sb2I9, and Cs3Bi2I9 exhibit high resistivity and photoconductivity response under laser photoexcitation, indicating that these compounds possess potential as semiconductor hard radiation detector materials.« less

Temperature and composition phase diagram in the iron-based ladder compounds Ba 1 - x Cs x Fe 2 Se 3

DOE PAGES

Hawai, Takafumi; Nambu, Yusuke; Ohgushi, Kenya; ...

2015-05-28

We investigated the iron-based ladder compounds (Ba,Cs)Fe₂Se₃. Their parent compounds BaFe₂Se₃ and CsFe₂Se₃ have different space groups, formal valences of Fe, and magnetic structures. Electrical resistivity, specific heat, magnetic susceptibility, x-ray diffraction, and powder neutron diffraction measurements were conducted to obtain a temperature and composition phase diagram of this system. Block magnetism observed in BaFe₂Se₃ is drastically suppressed with Cs doping. In contrast, stripe magnetism observed in CsFe₂Se₃ is not so fragile against Ba doping. A new type of magnetic structure appears in intermediate compositions, which is similar to stripe magnetism of CsFe₂Se₃, but interladder spin configuration is different. Intermediatemore » compounds show insulating behavior, nevertheless a finite T-linear contribution in specific heat was obtained at low temperatures.« less

A novel procedure for Rubidium separation and its isotope measurements on geological samples by MC-ICP-MS

NASA Astrophysics Data System (ADS)

Ma, J.; Zhang, Z.; Wei, G.; Zhang, L.

2017-12-01

A method including a novel column Rb separation procedure and high-precision Rb isotope measurement in geological materials by using multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) in standard-sample-bracketing (SSB) mode has been developed. Sr-Spec resin was employed, in which the distribution coefficients for Rb, K, Ba and Sr are different in nitric acid, to sequentially separate them from the matrix. The dissolved samples were loaded on the column in 3 M HNO3, the main matrix such as Al, Ca, Fe, Mg, Mn and Na were removed by rinsing with 4.5 mL HNO3, Rb and K were then sequentially eluted by 3 M HNO3 in different volumes. After that, Ba was eluted by 8 M HNO3, and Sr was finally eluted by Milli-Q water. This enable us to collect the pure Rb, K, Ba and Sr one by one with recovery close to 100% for their isotopic compositions measurement on MC-ICP-MS. We here focus on Rb isotope measurement. The measurement using MC-ICP-MS yielded an internal precision for δ87Rb of < ± 0.03‰ (2SE), and the external precision was generally better than ± 0.06‰ (2SD) based on the long-term results of the Rb standard solutions NIST SRM 984. A series of geological rock standards, were analyzed using this method, and the results indicate significant Rb isotope differences in different geologic materials. This will provide a powerful tool to investigate Rb isotope fractionation during geological processes.Based on this method, Rb isotope compositions from a basaltic weathering profile were carried out. The data show the lighter Rb (85Rb) isotope is preferentially leached from the weathering profile and remains heavy Rb isotope (87Rb) in the weathered residues during the incipient weathering stage. From the moderate to advanced weathering stage, the significant variations of Rb isotope were observed and multiple factors, such as leaching, adsorption, desorption, and precipitation, should play important role in fractionating Rb isotope.

Comparison of structure, morphology, and leach characteristics of multi-phase ceramics produced via melt processing and hot isostatic pressing

NASA Astrophysics Data System (ADS)

Dandeneau, Christopher S.; Hong, Tao; Brinkman, Kyle S.; Vance, Eric R.; Amoroso, Jake W.

2018-04-01

Melt processing of multi-phase ceramic waste forms offers potential advantages over traditional solid-state synthesis methods given both the prevalence of melters currently in use and the ability to reduce the possibility of airborne radionuclide contamination. In this work, multi-phase ceramics with a targeted hollandite composition of Ba1.0Cs0.3Cr1.0Al0.3Fe1.0Ti5.7O16 were fabricated by melt processing at 1675 °C and hot isostatic pressing (HIP) at 1250 and 1300 °C. X-ray diffraction analysis (XRD) confirmed hollandite as the major phase in all specimens. Zirconolite/pyrochlore peaks and weaker perovskite reflections were observed after melt processing, while HIP samples displayed prominent perovskite peaks and low-intensity zirconolite reflections. Melt processing produced specimens with large (>50 μm) well-defined hollandite grains, while HIP yielded samples with a more fine-grained morphology. Elemental analysis showed "islands" rich in Cs and Ti across the surface of the 1300 °C HIP sample, suggesting partial melting and partitioning of Cs into multiple phases. Photoemission data revealed multiple Cs 3d spin-orbit pairs for the HIP samples, with the lower binding energy doublets likely corresponding to Cs located in more leachable phases. Among all specimens examined, the melt-processed sample exhibited the lowest fractional release rates for Rb and Cs. However, the retention of Sr and Mo was greater in the HIP specimens.

Radioactive Cs capture in the early solar system

PubMed Central

Hidaka, Hiroshi; Yoneda, Shigekazu

2013-01-01

Barium isotopic compositions of primitive materials in the solar system are generally affected by s- and r-process nucleosynthetic components that hide the contribution of the isotopic excess of 135Ba formed by decay of radioactive 135Cs. However, the Ba isotopic composition of the chemical separates from chondrules in the Sayama CM2 chondrite shows an excess of 135Ba isotopic abundance up to (0.33 ± 0.06)%, which is independent of the isotopic components from s- and r-process nucleosyntheses. The isotopic excesses of 135Ba correlate with the elemental abundance of Ba relative to Cs, providing chemical and isotopic evidence for the existence of the presently extinct radionuclide 135Cs (t1/2 = 2.3 million years) in the early solar system. The estimated abundance of 135Cs/133Cs = (6.8 ± 1.9) × 10−4 is more than double that expected from the uniform production model of the short-lived radioisotopes, suggesting remobilization of Cs including 135Cs in the chondrules of the meteorite parent body. PMID:23435551

Geochemistry and mineralogy of late Quaternary loess in the upper Mississippi River valley, USA: Provenance and correlation with Laurentide Ice Sheet history

USGS Publications Warehouse

Muhs, Daniel; Bettis, E. Arthur; Skipp, Gary L.

2018-01-01

The midcontinent of North America contains some of the thickest and most extensive last-glacial loess deposits in the world, known as Peoria Loess. Peoria Loess of the upper Mississippi River valley region is thought to have had temporally varying glaciogenic sources resulting from inputs of sediment to the Mississippi River from different lobes of the Laurentide Ice Sheet. Here, we explore a new method of determining loess provenance using K/Rb and K/Ba values (in K-feldspars and micas) in loess from a number of different regions in North America. Results indicate that K/Rb and K/Ba values can distinguish loess originating from diverse geologic terrains in North America. Further, different loess bodies that are known to have had the same source sediments (using other criteria) have similar K/Rb and K/Ba values. We also studied three thick loess sections in the upper Mississippi River valley region. At each site, the primary composition of the loess changed over the course of the last glacial period, and K/Rb and K/Ba values parallel changes in carbonate mineral content and clay mineralogy. We thus confirm conclusions of earlier investigators that loess composition changed as a result of the shifting dominance of different lobes of the Laurentide Ice Sheet and the changing course of the Mississippi River. We conclude that K/Rb and K/Ba values are effective, robust, and rapid indicators of loess provenance that can be applied to many regions of the world.

Evaluation of simple geochemical indicators of aeolian sand provenance: Late Quaternary dune fields of North America revisited

USGS Publications Warehouse

Muhs, Daniel

2017-01-01

Dune fields of Quaternary age occupy large areas of the world's arid and semiarid regions. Despite this, there has been surprisingly little work done on understanding dune sediment provenance, in part because many techniques are time-consuming, prone to operator error, experimental, highly specialized, expensive, or require sophisticated instrumentation. Provenance of dune sand using K/Rb and K/Ba values in K-feldspar in aeolian sands of the arid and semiarid regions of North America is tested here. Results indicate that K/Rb and K/Ba can distinguish different river sands that are sediment sources for dunes and dune fields themselves have distinctive K/Rb and K/Ba compositions. Over the Basin and Range and Great Plains regions of North America, the hypothesized sediment sources of dune fields are reviewed and assessed using K/Rb and K/Ba values in dune sands and in hypothesized source sediments. In some cases, the origins of dunes assessed in this manner are consistent with previous studies and in others, dune fields are found to have a more complex origin than previously thought. Use of K/Rb and K/Ba for provenance studies is a robust method that is inexpensive, rapid, and highly reproducible. It exploits one of the most common minerals found in dune sand, K-feldspar. The method avoids the problem of using simple concentrations of key elements that may be subject to interpretative bias due to changes in mineralogical maturity of Quaternary dune fields that occur over time.

Geochemistry and mineralogy of late Quaternary loess in the upper Mississippi River valley, USA: Provenance and correlation with Laurentide Ice Sheet history

NASA Astrophysics Data System (ADS)

Muhs, Daniel R.; Bettis, E. Arthur; Skipp, Gary L.

2018-05-01

The midcontinent of North America contains some of the thickest and most extensive last-glacial loess deposits in the world, known as Peoria Loess. Peoria Loess of the upper Mississippi River valley region is thought to have had temporally varying glaciogenic sources resulting from inputs of sediment to the Mississippi River from different lobes of the Laurentide Ice Sheet. Here, we explore a new method of determining loess provenance using K/Rb and K/Ba values (in K-feldspars and micas) in loess from a number of different regions in North America. Results indicate that K/Rb and K/Ba values can distinguish loess originating from diverse geologic terrains in North America. Further, different loess bodies that are known to have had the same source sediments (using other criteria) have similar K/Rb and K/Ba values. We also studied three thick loess sections in the upper Mississippi River valley region. At each site, the primary composition of the loess changed over the course of the last glacial period, and K/Rb and K/Ba values parallel changes in carbonate mineral content and clay mineralogy. We thus confirm conclusions of earlier investigators that loess composition changed as a result of the shifting dominance of different lobes of the Laurentide Ice Sheet and the changing course of the Mississippi River. We conclude that K/Rb and K/Ba values are effective, robust, and rapid indicators of loess provenance that can be applied to many regions of the world.

Interplay of Cation Ordering and Ferroelectricity in Perovskite Tin Iodides: Designing a Polar Halide Perovskite for Photovoltaic Applications

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

Gou, Gaoyang; Young, Joshua; Liu, Xian

2016-09-28

Owing to its ideal semiconducting band gap and good carrier transport properties, the fully inorganic perovskite CsSnI 3 has been proposed as a visible-light absorber for photovoltaic (PV) applications. However, compared to the organic inorganic lead halide perovskite CH 3NH 3PbI 3, CsSnI 3 solar cells display very low energy conversion efficiency. In this work, we propose a potential route to improve the PV properties of CsSnI 3. Using first-principles calculations, we examine the crystal structures and electronic properties of CsSnI 3, including its structural polymorphs. Next, we purposefully order Cs and Rb cations on the A site to createmore » the double perovskite (CsRb)Sn 2I 6. We find that a stable ferroelectric polarization arises from the nontrivial coupling between polar displacements and octahedral rotations of the SnI 6 network. These ferroelectric double perovskites are predicted to have energy band gaps and carrier effective masses similar to those of CsSnI 3. More importantly, unlike nonpolar CsSnI 3, the electric polarization present in ferroelectric (CsRb)Sn 2I 6 can effectively separate the photoexcited carriers, leading to novel ferroelectric PV materials with,potentially enhanced energy conversion efficiency.« less

Na, K, Rb, and Cs Exchange in Heulandite Single-Crystals: X-Ray Structure Refinements at 100 K

NASA Astrophysics Data System (ADS)

Yang, Ping; Armbruster, Thomas

1996-04-01

The crystal structures of Na-, K-, Rb-, and Cs-exchanged varieties of the zeolite heulandite with the simplified compositionM+9Al9Si27O72·nH2O were studied by single-crystal X-ray diffraction at 100 K. The structure refinements of Na-, K-, and Rb-exchanged heulandite were performed in space groupC2/mwith resultantRvalues of 3.8, 3.0, and 4.9%, respectively. Cs-exchanged heulandite was refined in space groupC[formula], yielding anRvalue of 3.4%. X-ray single-crystal data of the Cs-exchanged variety indicated that many reflections of typeh k lwere not equivalent toh -k las expected for monoclinic symmetry. With increasing radius of the incorporated channel cations, thebaxis increases from 17.93 to 18.09 Å leading to a slight widening of the channels. The number of H2O molecules also decreases with increasing cation radius due to space limitations. Three general cation positions (II-1,C3, andB4) were found in the four exchanged heulandite samples. For Rb- and Cs-exchanged crystals, the additional cation siteA2 occurs. In Cs-exchanged heulandite symmetry lowering is due to partial Si, Al ordering in the framework accompanied with a more asymmetric arrangement of channel Cs. Only if heavy elements in the channels are present the symmetry information of the framework is enforced, thus partial Si, Al ordering can be resolved.

Cation displacements and the structures of the superconducting pyrochlore osmates AOs2O6 ( A=K , Rb, and Cs)

NASA Astrophysics Data System (ADS)

Galati, Rosa; Simon, Charles; Henry, Paul F.; Weller, Mark T.

2008-03-01

Variable temperature, 2K

Lithium and boron in late-orogenic granites - Isotopic fingerprints for the source of crustal melts?

NASA Astrophysics Data System (ADS)

Romer, Rolf L.; Meixner, Anette; Förster, Hans-Jürgen

2014-04-01

Geochemically diverse late- and post-Variscan granites of the Erzgebirge-Vogtland, the Saxon Granulite Massif, and Thuringia (Germany) formed by anatectic melting of Palaeozoic sedimentary successions and associated mafic to felsic volcanic rocks. The compositional diversity of the least evolved of these granites is largely inherited from the protoliths. We present Li and B-isotopic data of these granites and compare them with the isotopic composition of their protoliths, to investigate whether (i) there exist systematic differences in the Li and B-isotopic composition among different granite types and (ii) Li and B-isotopic compositions provide information on the granite sources complementary to information from the isotopic composition of Sr, Nd, and Pb and the trace-element signatures. Low-F biotite and two-mica granite types have flat upper continental crust (UCC)-normalized trace-element pattern with variable enrichments in Li, Rb, Cs, Sn, and W and depletions in Sr, Ba, and Eu. These signatures are least pronounced for the Niederbobritzsch biotite granite, which has the largest contribution of mafic material, and most pronounced for the two-mica granites. The granites show a relatively narrow range of δ7Li values (-3.0 to -0.5) and a broad range of δ11B values (-13.4 to +20.1). The δ11B values are lower in rocks with distinctly higher contents of Li, Rb, Cs, and Sn. The high δ11B of the Niederbobritzsch granite may be explained by the melting of former altered oceanic crust in its source. Relative to UCC, intermediate-F to high-F low-P granites show strong depletions in Sr, Ba, Eu as well as Zr and Hf, strong enrichments in Li, Rb, and Cs as well as Nb, Sn, Ta, and W, and REE pattern with stronger enrichments for HREE than for LREE. These granites show narrow ranges of δ7Li (-2.0 to +1.6) and δ11B values (-14.7 to -9.1), reflecting the smaller variability of the Li and B-isotopic composition in their source lithologies. The anomalously high δ7Li value (14.7) of one granite sample (Burgberg), which is similar to δ7Li values of its wall rocks (up to 14.5), may indicate late-magmatic fluid-rock interaction with external, wall rock-derived fluids. Because of the small compositional range of most source lithologies, the Li and B-isotopic variation in the granites is also small indicating that the isotopic composition of Li and B does not represent a particularly sensitive source tracer, with the exception of source lithologies characterized by extreme δ7Li or δ11B values.

The hydration structure of the heavy-alkalines Rb+ and Cs+ through molecular dynamics and X-ray absorption spectroscopy: surface clusters and eccentricity.

PubMed

Caralampio, Daniel Z; Martínez, José M; Pappalardo, Rafael R; Marcos, Enrique Sánchez

2017-11-01

Physicochemical properties of the two heaviest stable alkaline cations, Rb + and Cs + , in water have been examined from classical molecular dynamics (MD) simulations. Alkaline cation-water intermolecular potentials have been built from ab initio interaction energies of [M(H 2 O) n ] + clusters. Unlike in the case of other monatomic metal cations, the sampling needed the inclusion of surface clusters to properly describe the interactions. The first coordination shell is found at an average M-O distance of 2.87 Å and 3.12 Å for Rb + and Cs + , respectively, with coordination numbers of 8 and 10. Structural, dynamical and energetic properties are discussed on the basis of the delicate compromise among the ion-water and water-water interactions which contribute almost on the same foot to the definition of the solvent structure around the ions. A significant asymmetry is detected in the Rb + and Cs + first hydration shell. Reorientational times of first-shell water molecules for Cs + support a clear structure-breaking nature for this cation, whereas the Rb + values do not differ from pure water behavior. Experimental EXAFS and XANES spectra have been compared to simulated ones, obtained by means of application of the FEFF code to a set of statistically significant structures taken from the MD simulations. Due to the presence of multi-excitations in the absorption spectra, theoretical-experimental agreement for the EXAFS spectra is reached when the multi-excitations are removed from the experimental spectra.

Testing Room-Temperature Ionic Liquid Solutions for Depot Repair of Aluminum Coatings

DTIC Science & Technology

2011-05-01

Ne 3 Na Mg IIIB IVB VB VIB VIIB ------ VIIIB ------ IB IIB Al Si P S Cl Ar 4 K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr 5 Rb Sr Y Zr Nb Mo Tc...Ru Rh Pd Ag Cd In Sn Sb Te I Xe 6 Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn 7 Fr Ra Ac Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu Th Pa U Np...Electroplating Bath Lid Arrangement ;:::::::::::=== Thermometer Purge gas vent Anode lead Cathode lead (Extractable from the lid) Purge feed gas

Cation ordering and effect of biaxial strain in double perovskite CsRbCaZnCl 6

DOE PAGES

Pilania, G.; Uberuaga, B. P.

2015-03-19

Here, we investigate the electronic structure, energetics of cation ordering, and effect of biaxial strain on double perovskite CsRbCaZnCl 6 using first-principles calculations based on density functional theory. The two constituents (i.e., CsCaCl 3 and RbZnCl 3) forming the double perovskite exhibit a stark contrast. While CsCaCl 3 is known to exist in a cubic perovskite structure and does not show any epitaxial strain induced phase transitions within an experimentally accessible range of compressive strains, RbZnCl 3 is thermodynamically unstable in the perovskite phase and exhibits ultra-sensitive response at small epitaxial strains if constrained in the perovskite phase. We showmore » that combining the two compositions in a double perovskite structure not only improves overall stability but also the strain-polarization coupling of the material. Our calculations predict a ground state with P4/nmm space group for the double perovskite, where A-site cations (i.e., Cs and Rb) are layer-ordered and B-site cations (i.e., Ca and Zn) prefer a rocksalt type ordering. The electronic structure and bandgap in this system are shown to be quite sensitive to the B-site cation ordering and is minimally affected by the ordering of A-site cations. We find that at experimentally accessible compressive strains CsRbCaZnCl 6 can be phase transformed from its paraelectric ground state to an antiferroelectric state, where Zn atoms contribute predominantly to the polarization. Furthermore, both energy difference and activation barrier for a transformation between this antiferroelectric state and the corresponding ferroelectric configuration are predicted to be small. As a result, the computational approach presented here opens a new pathway towards a rational design of novel double perovskites with improved strain response and functionalities.« less

Na, Rb and Cs partitioning between metal, silicate and sulfide: Implications for volatile depletion in terrestrial planets

NASA Astrophysics Data System (ADS)

Boujibar, A.; Fei, Y.; Du, Z.; Righter, K.; Bullock, E. S.

2017-12-01

Inner Solar System materials are known for their depletion in volatile elements, including the moderately volatile alkalis: Na, K, Rb, and Cs. The origin of this depletion is still uncertain, as several processes could have been involved, during the nebular condensation or planetary accretion. Volatile depletion is commonly estimated through comparison of alkali concentrations relatively to those of chondrites, assuming they remain in planetary mantles during core segregation. However, experimental studies show that substantial K can partition into metals that are enriched in sulfur and oxygen. Several models have also suggested that sulfides may have played an important role during episodes of sulfide segregation from a crystallizing magma ocean (sulfide matte) or accretion of S-rich planetary embryos. For Mercury, a sulfide layer could be present between core and mantle, due to immiscibility between Si-rich and S-rich metals. Therefore, here we investigate whether alkali elements (Na, Cs and Rb) could be partly sequestered in planetary cores during their differentiation. We conducted experiments at high pressure and temperature (1 to 5 GPa and up to 1900 °C) to determine partition coefficients of Na, Rb and Cs between metal and silicate. Our results show that pressure, temperature, sulfur and oxygen in metals enhance the partitioning of Na, Rb and Cs into metals, as previously found for K. For all three investigated alkalis (Na, Rb and Cs), we found a maximum partition coefficient of 1 between sulfides containing 13 wt% O and silicate melt. Therefore, S-rich cores or sulfide layers formed due to immiscibility in Fe-S-O systems could have acted as important geochemical reservoirs for alkali elements. Using our experimental data and different assumptions on initial bulk abundances, we evaluate volatile depletion in terrestrial planets, by comparing resulting mantle alkali concentrations after core segregation, with actual concentrations in the Earth's mantle.

Syntheses, structural variants and characterization of AInM′S{sub 4} (A=alkali metals, Tl; M′ = Ge, Sn) compounds; facile ion-exchange reactions of layered NaInSnS{sub 4} and KInSnS{sub 4} compounds

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

Yohannan, Jinu P.; Vidyasagar, Kanamaluru, E-mail: kvsagar@iitm.ac.in

Ten AInM′S{sub 4} (A=alkali metals, Tl; M′= Ge, Sn) compounds with diverse structure types have been synthesized and characterized by single crystal and powder X-ray diffraction and a variety of spectroscopic methods. They are wide band gap semiconductors. KInGeS{sub 4}(1-β), RbInGeS{sub 4}(2), CsInGeS{sub 4}(3-β), TlInGeS{sub 4}(4-β), RbInSnS{sub 4}(8-β) and CsInSnS{sub 4}(9) compounds with three-dimensional BaGa{sub 2}S{sub 4} structure and CsInGeS{sub 4}(3-α) and TlInGeS{sub 4}(4-α) compounds with a layered TlInSiS{sub 4} structure have tetrahedral [InM′S{sub 4}]{sup −} frameworks. On the other hand, LiInSnS{sub 4}(5) with spinel structure and NaInSnS{sub 4}(6), KInSnS{sub 4}(7), RbInSnS{sub 4}(8-α) and TlInSnS{sub 4}(10) compounds with layered structuremore » have octahedral [InM′S{sub 4}]{sup −} frameworks. NaInSnS{sub 4}(6) and KInSnS{sub 4}(7) compounds undergo facile topotactic ion-exchange, at room temperature, with various mono-, di- and tri-valent cations in aqueous medium to give rise to metastable layered phases. - Graphical abstract: NaInSnS{sub 4} and KInSnS{sub 4} compounds undergo, in aqueous medium at room temperature, facile topotactic ion-exchange with mono, di and trivalent cations. Display Omitted - Highlights: • Ten AInM′S{sub 4} compounds with diverse structure types were synthesized. • They are wide band gap semiconductors. • NaInSnS{sub 4} and KInSnS{sub 4} compounds undergo facile topotactic ion-exchange at room temperature.« less

High-resolution laser spectroscopy of hot Cs and Rb vapor confined in a thin optical cell

NASA Astrophysics Data System (ADS)

Todorov, P.; Krasteva, A.; Vartanyan, T.; Todorov, G.; Sarkisyan, D.; Cartaleva, S.

2018-03-01

We propose a novel use of an optical cell of micrometer thickness filled with Cs vapor in view of studying the collisions between two different alkali atoms of strongly different densities. We demonstrate narrow and good-contrast sub-Doppler resonances at the Rb D2 line for a mean-free-path of the Cs atoms comparable to the optical cell longitudinal dimension; the resonances are completely destroyed when the mean-free-path of the Cs atoms is more than two orders of magnitude shorter than the longitudinal dimension of the thin cell.

Permeation of internal and external monovalent cations through the catfish cone photoreceptor cGMP-gated channel

PubMed Central

1995-01-01

The permeation of monovalent cations through the cGMP-gated channel of catfish cone outer segments was examined by measuring permeability and conductance ratios under biionic conditions. For monovalent cations presented on the cytoplasmic side of the channel, the permeability ratios with respect to extracellular Na followed the sequence NH4 > K > Li > Rb = Na > Cs while the conductance ratios at +50 mV followed the sequence Na approximately NH4 > K > Rb > Li = Cs. These patterns are broadly similar to the amphibian rod channel. The symmetry of the channel was tested by presenting the test ion on the extracellular side and using Na as the common reference ion on the cytoplasmic side. Under these biionic conditions, the permeability ratios with respect to Na at the intracellular side followed the sequence NH4 > Li > K > Na > Rb > Cs while the conductance ratios at +50 mV followed the sequence NH4 > K approximately Na > Rb > Li > Cs. Thus, the channel is asymmetric with respect to external and internal cations. Under symmetrical 120 mM ionic conditions, the single-channel conductance at +50 mV ranged from 58 pS in NH4 to 15 pS for Cs and was in the order NH4 > Na > K > Rb > Cs. Unexpectedly, the single-channel current-voltage relation showed sufficient outward rectification to account for the rectification observed in multichannel patches without invoking voltage dependence in gating. The concentration dependence of the reversal potential for K showed that chloride was impermeant. Anomalous mole fraction behavior was not observed, nor, over a limited concentration range, were multiple dissociation constants. An Eyring rate theory model with a single binding site was sufficient to explain these observations. PMID:8786344

Solid-state NMR study of various mono- and divalent cation forms of the natural zeolite natrolite.

PubMed

Park, Min Bum; Vicente, Aurélie; Fernandez, Christian; Hong, Suk Bong

2013-05-28

Here we present the one-dimensional (29)Si and (27)Al MAS NMR and two-dimensional (27)Al MQMAS and DQF-STMAS NMR spectra of the monovalent (Na(+), K(+), Rb(+), Cs(+) and NH4(+)) and divalent (Ca(2+), Sr(2+) and Ba(2+)) cation forms of the natural zeolite natrolite (framework type NAT) with complete Si-Al ordering over the crystallographically distinct tetrahedral sites and with the same hydration state (hydrated, partially dehydrated or fully dehydrated). In the case of monovalent cation-exchanged natrolites, the differences in their crystal symmetry evidenced by (29)Si MAS NMR were found to be in good agreement with those determined by crystallographic analyses. However, (27)Al DQF-STMAS NMR spectroscopy shows the presence of two distinct Al sites in dehydrated K-NAT, Rb-NAT and NH4-NAT, suggesting that their actual crystal symmetry is lower than the reported one (i.e., orthorhombic Fdd2). The MAS NMR results also show that the space group of hydrated Ca-NAT is lower than that (monoclinic F1d1) of hydrated scolecite, the natural calcium counterpart of natrolite, which is also the case with hydrated Sr-NAT and Ba-NAT. We believe that the unexpected diversity in the crystal symmetry of natrolite caused by exchange of various mono- and divalent ions, as well as by dehydration, may be inherently due to the high framework flexibility of this natural zeolite.

The performance of moss, grass, and 1- and 2-year old spruce needles as bioindicators of contamination: a comparative study at the scale of the Czech Republic.

PubMed

Suchara, Ivan; Sucharova, Julie; Hola, Marie; Reimann, Clemens; Boyd, Rognvald; Filzmoser, Peter; Englmaier, Peter

2011-05-01

Moss (Pleurozium schreberi), grass (Avenella flexuosa), and 1- and 2-year old spruce (Picea abies) needles were collected over the territory of the Czech Republic at an average sample density of 1 site per 290km(2). The samples were analysed for 39 elements (Ag, Al, As, Ba, Be, Bi, Ca, Cd, Ce, Co, Cr, Cs, Cu, Fe, Ga, Hg, K, La, Li, Mg, Mn, Mo, Na, Nd, Ni, Pb, Pr, Rb, S, Sb, Se, Sn, Sr, Th, Tl, U, V, Y and Zn) using ICP-MS and ICP-AES techniques (the major nutrients Ca, K, Mg and Na were not analysed in moss). Moss showed by far the highest element concentrations for most elements. Exceptions were Ba (spruce), Mn (spruce), Mo (grass), Ni (spruce), Rb (grass) and S (grass). Regional distribution maps and spatial trend analysis were used to study the suitability of the four materials as bioindicators of anthropogenic contamination. The highly industrialised areas in the north-west and the far east of the country and several more local contamination sources were indicated in the distribution maps of one or several sample materials. At the scale of the whole country moss was the best indicator of known contamination sources. However, on a more local scale, it appeared that spruce needles were especially well suited for detection of urban contamination. Copyright © 2010 Elsevier B.V. All rights reserved.

Temperature and composition phase diagram in the iron-based ladder compounds Ba1-xCsxFe2Se3

NASA Astrophysics Data System (ADS)

Hawai, Takafumi; Nambu, Yusuke; Ohgushi, Kenya; Du, Fei; Hirata, Yasuyuki; Avdeev, Maxim; Uwatoko, Yoshiya; Sekine, Yurina; Fukazawa, Hiroshi; Ma, Jie; Chi, Songxue; Ueda, Yutaka; Yoshizawa, Hideki; Sato, Taku J.

2015-05-01

We investigated the iron-based ladder compounds (Ba,Cs ) Fe2Se3 . Their parent compounds BaFe2Se3 and CsFe2Se3 have different space groups, formal valences of Fe, and magnetic structures. Electrical resistivity, specific heat, magnetic susceptibility, x-ray diffraction, and powder neutron diffraction measurements were conducted to obtain a temperature and composition phase diagram of this system. Block magnetism observed in BaFe2Se3 is drastically suppressed with Cs doping. In contrast, stripe magnetism observed in CsFe2Se3 is not so fragile against Ba doping. A new type of magnetic structure appears in intermediate compositions, which is similar to stripe magnetism of CsFe2Se3 , but interladder spin configuration is different. Intermediate compounds show insulating behavior, nevertheless a finite T -linear contribution in specific heat was obtained at low temperatures.

The peculiar geochemical signatures of São Miguel (Azores) lavas: Metasomatised or recycled mantle sources?

NASA Astrophysics Data System (ADS)

Beier, Christoph; Stracke, Andreas; Haase, Karsten M.

2007-07-01

The island of São Miguel, Azores consists of four large volcanic systems that exhibit a large systematic intra-island Sr-Nd-Pb-Hf isotope and trace element variability. The westernmost Sete Cidades volcano has moderately enriched Sr-Nd-Pb-Hf isotope ratios. In contrast, lavas from the easternmost Nordeste volcano have unusually high Sr and Pb and low Nd and Hf isotope ratios suggesting a long-term evolution with high Rb/Sr, U/Pb, Th/Pb, Th/U and low Sm/Nd and Lu/Hf parent-daughter ratios. They have trace element concentrations similar to those of the HIMU islands, with the exception of notably higher alkali element (Cs, Rb, K, Ba) and Th concentrations. The time-integrated parent-daughter element evolution of both the Sete Cidades and Nordeste source matches the incompatibility sequence commonly observed during mantle melting and consequently suggests that the mantle source enrichment is caused by a basaltic melt, either as a metasomatic agent or as recycled oceanic crust. Our calculations show that a metasomatic model involving a small degree basaltic melt is able to explain the isotopic enrichment but, invariably, produces far too enriched trace element signatures. We therefore favour a simple recycling model. The trace element and isotopic signatures of the Sete Cidades lavas are consistent with the presence of ancient recycled oceanic crust that has experienced some Pb loss during sub-arc alteration. The coherent correlation of the parent-daughter ratios (e.g. Rb/Sr, Th/U, U/Pb) and incompatible element ratios (e.g. Nb/Zr, Ba/Rb, La/Nb) with the isotope ratios in lavas from the entire island suggest that the Sete Cidades and Nordeste source share a similar genetic origin. The more enriched trace element and isotopic variations of Nordeste can be reproduced by recycled oceanic crust in the Nordeste source that contains small amounts of evolved lavas (˜ 1-2%), possibly from a subducted seamount. The rare occurrence of enriched source signatures comparable to Nordeste may be taken as circumstantial evidence that stirring processes in the Earth's mantle are not able to homogenise material within the size of seamounts over timescales of mantle recycling.

The band systems of alkali vapors

NASA Technical Reports Server (NTRS)

Weizel, W.; Kulp, M.

1988-01-01

A number of band edges of the molecules, Na2, K2, NaK, NaCs, LiK, LiRb, LiCs, and NaRb are arranged in edge schemes. The vibrational quanta of the base terms and the upper terms can be approximately determined. Viewpoints are produced for interpreting electron terms. The terms Na2 are interpreted as terms of a photo-electron.

Lifetime of vibrational levels from Fourier grid calculations: RbCs example.

PubMed

Londoño, B E; Mahecha, J; Luc-Koenig, E; Crubellier, A

2011-11-14

We present systematic calculations of the lifetimes of vibrational levels of excited Rb(5s)Cs(6p(1/2)) 0(+) electronic states. We show that a precise description of the variation with the internuclear distance of the transition dipole moment between electronic states is essential. It is also crucial to account precisely for the spin-orbit coupling between the Rb(5s)Cs(6p) A (1)Σ(+) and b (3)Π states. We describe the general trends of the probability of formation of stable molecules in the Rb(5s)Cs(6s) X (1)Σ(+) and a (3)Σ(+) electronic states, through radiative decay from the 0(+)v' levels, together with the branching ratios for the obtention of singlet or triplet molecules, stable with respect to dissociation. Furthermore, this analysis allows us to demonstrate the efficiency of the Mapped Fourier Grid Hamiltonian Representation method (MFGHR) to determine rigorously the energy variation, throughout the continuous part of the spectrum, of the density of an observable connecting bound vibrational levels and continuum states. The resolution in energy can be adapted to the studied problem through a judicious choice of the grid parameters.

Phase Behavior of Complex Superprotonic Solid Acids

NASA Astrophysics Data System (ADS)

Panithipongwut, Chatr

Superprotonic phase transitions and thermal behaviors of three complex solid acid systems are presented, namely Rb3H(SO4) 2-RbHSO4 system, Rb3H(SeO4)2-Cs 3H(SeO4)2 solid solution system, and Cs6 (H2SO4)3(H1.5PO4) 4. These material systems present a rich set of phase transition characteristics that set them apart from other, simpler solid acids. A.C. impedance spectroscopy, high-temperature X-ray powder diffraction, and thermal analysis, as well as other characterization techniques, were employed to investigate the phase behavior of these systems. Rb3H(SO4)2 is an atypical member of the M3H(XO4)2 class of compounds (M = alkali metal or NH4+ and X = S or Se) in that a transition to a high-conductivity state involves disproportionation into two phases rather than a simple polymorphic transition [1]. In the present work, investigations of the Rb3H(SO4)2-RbHSO4 system have revealed the disproportionation products to be Rb2SO 4 and the previously unknown compound Rb5H3(SO 4)4. The new compound becomes stable at a temperature between 25 and 140 °C and is isostructural to a recently reported trigonal phase with space group P3m of Cs5H 3(SO4)4 [2]. At 185 °C the compound undergoes an apparently polymorphic transformation with a heat of transition of 23.8 kJ/mol and a slight additional increase in conductivity. The compounds Rb3H(SeO4)2 and Cs 3H(SeO4)2, though not isomorphous at ambient temperatures, are quintessential examples of superprotonic materials. Both adopt monoclinic structures at ambient temperatures and ultimately transform to a trigonal (R3m) superprotonic structure at slightly elevated temperatures, 178 and 183 °C, respectively. The compounds are completely miscible above the superprotonic transition and show extensive solubility below it. Beyond a careful determination of the phase boundaries, we find a remarkable 40-fold increase in the superprotonic conductivity in intermediate compositions rich in Rb as compared to either end-member. The compound Cs6(H2SO4)3(H 1.5PO4)4 is unusual amongst solid acid compounds in that it has a complex cubic structure at ambient temperature and apparently transforms to a simpler cubic structure of the CsCl-type (isostructural with CsH2PO4) at its transition temperature of 100-120 °C [3]. Here it is found that, depending on the level of humidification, the superprotonic transition of this material is superimposed with a decomposition reaction, which involves both exsolution of (liquid) acid and loss of H2O. This reaction can be suppressed by application of sufficiently high humidity, in which case Cs6(H2SO4)3(H 1.5PO4)4 undergoes a true superprotonic transition. It is proposed that, under conditions of low humidity, the decomposition/dehydration reaction transforms the compound to Cs6(H2-0.5xSO 4)3(H1.5PO4)4-x, also of the CsCl structure type at the temperatures of interest, but with a smaller unit cell. With increasing temperature, the decomposition/dehydration proceeds to greater and greater extent and unit cell of the solid phase decreases. This is identified to be the source of the apparent negative thermal expansion behavior. References: [1] L.A. Cowan, R.M. Morcos, N. Hatada, A. Navrotsky, S.M. Haile, Solid State Ionics 179 (2008) (9-10) 305. [2] M. Sakashita, H. Fujihisa, K.I. Suzuki, S. Hayashi, K. Honda, Solid State Ionics 178 (2007) (21-22) 1262. [3] C.R.I. Chisholm, Superprotonic Phase Transitions in Solid Acids: Parameters affecting the presence and stability of superprotonic transitions in the MHnXO4 family of compounds (X=S, Se, P, As; M=Li, Na, K, NH4, Rb, Cs), Materials Science, California Institute of Technology, Pasadena, California (2003).

Ion selective electrode for cesium based on 5-(4'-nitrophenylazo)25,27-bis(2-propyloxy)26,28-dihydroxycalix[4]arene.

PubMed

Ramanjaneyulu, P S; Singh, Parminder; Sayi, Y S; Chawla, H M; Ramakumar, K L

2010-03-15

A polyvinylchloride (PVC) based liquid membrane ion selective electrode (ISE) for cesium was fabricated with 5-(4'-nitrophenylazo)25,27-bis(2-propyloxy)26,28-dihydroxycalix[4]arene as ionophore. Different membrane constituents were investigated to realise optimum performance of the ISE developed. Of the four plasticizers and two ion additives studied, the best response was observed with membrane having 2-nitro phenyl octyl ether (oNPOE) as plasticizer and potassium tetrakis (perchloro phenyl) borate (KTpClPB) as ion additive. Linear response over concentration range of 10(-5)-10(-1)M CsCl was obtained. The Nernstian slope of the response was 56 mV per decade for Cs with a response time less than 20s. Matched potential method has been applied to find out the selectivity for Cs over several ions like Rb(+), K(+), Na(+), NH(4)(+), Sr(2+), Ba(2+), Ca(2+), Mg(2+), Cu(2+), Pb(2+), Zn(2+), Ni(2+) and Ce(3+). The response of ISE for Cs(+) was fairly constant over the pH range of 3-11. The lifetime of the electrode is 9 months which is the longest life for any membrane-based Cs-ISE so far developed. The concentration of cesium in two simulated high level active waste streams was determined and results agreed well with those obtained independently employing atomic absorption spectrometry. (c) 2009 Elsevier B.V. All rights reserved.

Ba 0.4 Rb 0.6 Mn 2 As 2 : A prototype half-metallic ferromagnet

DOE PAGES

Pandey, Abhishek; Johnston, D. C.

2015-11-02

Half-metallic ferromagnetism (FM) in single-crystal Ba 0.39(1)Rb 0.61(1)Mn 2As 2 below its Curie temperature T C = 103(2) K is reported. The magnetization M versus applied magnetic field H isotherm data at 1.8 K show complete polarization of the itinerant doped-hole magnetic moments that are introduced by substituting Rb for Ba. Here, the material exhibits extremely soft FM, with unobservably small remanent magnetization and coercive field. Surprisingly, and contrary to typical itinerant FMs, the M(H) data follow the Arrott-plot paradigm that is based on a mean-field theory of local-moment FMs. The in-plane electrical resistivity data are fitted well by anmore » activated-T 2 expression for T ≤ T C, whereas the data sharply deviate from this model for T > T C. Hence the activated-T 2 resistivity model is an excellent diagnostic for determining the onset of half-metallic FM in this compound, which in turn demonstrates the presence of a strong correlation between the electronic transport and magnetic properties of the material. Together with previous data on 40% hole-doped Ba 0.6K 0.4Mn 2As 2, these measurements establish 61%-doped Ba 0.39Rb 0.61Mn 2As 2 as a prototype for a class of half-metallic ferromagnets in which all the itinerant carriers in the material are ferromagnetic.« less

Atomic masses of {sup 6}Li,{sup 23}Na,{sup 39,41}K,{sup 85,87}Rb, and {sup 133}Cs

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

Mount, Brianna J.; Redshaw, Matthew; Myers, Edmund G.

2010-10-15

The atomic masses of the alkali-metal isotopes {sup 6}Li,{sup 23}Na,{sup 39,41}K,{sup 85,87}Rb, and {sup 133}Cs have been obtained from measurements of cyclotron frequency ratios of pairs of ions simultaneously trapped in a Penning trap. The results, with one standard deviation uncertainty, are: M({sup 6}Li)=6.015 122 887 4(16)u,M({sup 23}Na)=22.989769 282 8(26)u,M({sup 39}K)=38.963 706 485 6(52)u,M({sup 41}K)=40.961 825 257 4(48)u,M({sup 85}Rb)=84.911 789739(9)u,M({sup 87}Rb)=86.909 180 535(10)u, and M({sup 133}Cs)=132.905 451 963(13)u. Our mass of {sup 6}Li yields an improved neutron separation energy for {sup 7}Li of 7251.1014(45) keV.

Ionic conductivity and mixed-ion effect in mixed alkali metaphosphate glasses.

PubMed

Tsuchida, Jefferson Esquina; Ferri, Fabio Aparecido; Pizani, Paulo Sergio; Martins Rodrigues, Ana Candida; Kundu, Swarup; Schneider, José Fabián; Zanotto, Edgar Dutra

2017-03-01

In this work, mixed alkali metaphosphate glasses based on K-Na, Rb-Na, Rb-Li, Cs-Na and Cs-Li combinations were studied by differential scanning calorimetry (DSC), complex impedance spectroscopy, and Raman spectroscopy. DSC analyses show that both the glass transition (T g ) and melting temperatures (T m ) exhibit a clear mixed-ion effect. The ionic conductivity shows a strong mixed-ion effect and decreases by more than six orders of magnitude at room temperature for Rb-Na or Cs-Li alkali pairs. This study confirms that the mixed-ion effect may be explained as a natural consequence of random ion mixing because ion transport is favoured between well-matched energy sites and is impeded due to the structural mismatch between neighbouring sites for dissimilar ions.

Ion-neutral chemistry at ultralow energies:Dynamics of reactive collisions between laser-cooled Ca+ or Ba+ ions and Rb atoms in an ion-atom hybrid trap

NASA Astrophysics Data System (ADS)

Dulieu, O.; Hall, F. H. J.; Eberle, P.; Hegi, G.; Raoult, M.; Aymar, M.; Willitsch, S.

2013-05-01

Cold chemical reactions between laser-cooled Ca+ or Ba+ ions and Rb atoms were studied in an ion-atom hybrid trap. Reaction rate constants were determined in the collision energy range Ecoll /kB = 20 mK-20 K. Product branching ratios were studied using resonant-excitation mass spectrometry. The dynamics of the reactive processes including the radiative formation of CaRb+ and BaRb+ molecular ions has been analyzed using accurate potential energy curves and quantum-scattering calculations for the radiative channels. It is shown that the energy dependence of the reaction rates is governed by long-range interactions, while its magnitude is determined by short-range non-adiabatic and radiative couplings. The quantum character of the collisions is predicted to manifest itself in the occurrence of narrow shape resonances at well-defined collision energies. The present results highlight both universal and system-specific phenomena in cold ion-neutral collisions. This work was supported by the Swiss National Science Foundation and the COST Action ''Ion Traps for Tomorrow's Applications''.

Comparison of structure, morphology, and leach characteristics of multi-phase ceramics produced via melt processing and hot isostatic pressing

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

Dandeneau, Christopher S.; Hong, Tao; Brinkman, Kyle S.

Melt processing of multi-phase ceramic waste forms offers potential advantages over traditional solid-state synthesis methods given both the prevalence of melters currently in use and the ability to reduce the possibility of airborne radionuclide contamination. In this work, multi-phase ceramics with a targeted hollandite composition of Ba 1.0Cs 0.3Cr 1.0Al 0.3Fe 1.0Ti 5.7O 16 were fabricated by melt processing at 1675 °C and hot isostatic pressing (HIP) at 1250 and 1300 °C. X-ray diffraction analysis (XRD) confirmed hollandite as the major phase in all specimens. Zirconolite/pyrochlore peaks and weaker perovskite reflections were observed after melt processing, while HIP samples displayedmore » prominent perovskite peaks and low-intensity zirconolite reflections. Melt processing produced specimens with large (>50 μm) well-defined hollandite grains, while HIP yielded samples with a more fine-grained morphology. Elemental analysis showed “islands” rich in Cs and Ti across the surface of the 1300 °C HIP sample, suggesting partial melting and partitioning of Cs into multiple phases. Photoemission data revealed multiple Cs 3d spin-orbit pairs for the HIP samples, with the lower binding energy doublets likely corresponding to Cs located in more leachable phases. Among all specimens examined, the melt-processed sample exhibited the lowest fractional release rates for Rb and Cs. However, the retention of Sr and Mo was greater in the HIP specimens.« less

Comparison of structure, morphology, and leach characteristics of multi-phase ceramics produced via melt processing and hot isostatic pressing

DOE PAGES

Dandeneau, Christopher S.; Hong, Tao; Brinkman, Kyle S.; ...

2018-02-08

Melt processing of multi-phase ceramic waste forms offers potential advantages over traditional solid-state synthesis methods given both the prevalence of melters currently in use and the ability to reduce the possibility of airborne radionuclide contamination. In this work, multi-phase ceramics with a targeted hollandite composition of Ba 1.0Cs 0.3Cr 1.0Al 0.3Fe 1.0Ti 5.7O 16 were fabricated by melt processing at 1675 °C and hot isostatic pressing (HIP) at 1250 and 1300 °C. X-ray diffraction analysis (XRD) confirmed hollandite as the major phase in all specimens. Zirconolite/pyrochlore peaks and weaker perovskite reflections were observed after melt processing, while HIP samples displayedmore » prominent perovskite peaks and low-intensity zirconolite reflections. Melt processing produced specimens with large (>50 μm) well-defined hollandite grains, while HIP yielded samples with a more fine-grained morphology. Elemental analysis showed “islands” rich in Cs and Ti across the surface of the 1300 °C HIP sample, suggesting partial melting and partitioning of Cs into multiple phases. Photoemission data revealed multiple Cs 3d spin-orbit pairs for the HIP samples, with the lower binding energy doublets likely corresponding to Cs located in more leachable phases. Among all specimens examined, the melt-processed sample exhibited the lowest fractional release rates for Rb and Cs. However, the retention of Sr and Mo was greater in the HIP specimens.« less

Syntheses, structures, and physical properties of CsRE(2)Ag(3)Te(5) (RE = Pr, Nd, Sm, Gd-Er) and RbR(2)Ag(3)Te(5) (RE = Sm, Gd-Dy).

PubMed

Meng, Chang-Yu; Chen, Hong; Wang, Peng

2014-07-07

A new series of quaternary CsRE2Ag3Te5 (RE = Pr, Nd, Sm, Gd-Er) and RbRE2Ag3Te5 (RE = Sm, Gd-Dy), which have been synthesized from the elemental mixtures in ACl flux (A = Rb, Cs) and crystallized in the orthorhombic space group Cmcm, with a = 4.620(2)-4.504(2) Å, b = 16.232(8)-16.027(8) Å, c = 18.84(1)-18.32(2) and Z = 4, are isostructural to RbSm2Ag3Se5. These isostructural ARE2Ag3Te5 feature a three-dimensional tunnel framework constructed by ionically bound RETe6 octahedron and covalently bound AgTe4 tetrahedron in which tunnels are filled by A. Typical semiconducting behavior is revealed by the electrical conductivity, Seebeck coefficient, optical band gap measurement, and the theoretical calculations. The undoped sintered polycrystalline pellets of CsRE2Ag3Te5 (containing 1.1-1.7% CsCl impurity) show very low electrical conductivity (σr.t. = 0.5-2.4 S/cm), very low thermal conductivity (kr,t = 0.66-0.53 W/(m·K)), and moderate Seebeck coefficient (160-200 μV/K at 700 K).

Cask weeping mitigation

DOEpatents

Krumhansl, James L.; Brady, Patrick V.; Teter, David M.; McConnell, Paul

2007-09-18

A method (and concomitant kit) for treating a surface to reduce subsequent .sup.137Cs nuclide desorption comprising contacting the surface with a first cation-containing solution, the cation being one or more of Cs.sup.+, Rb.sup.+, Ag.sup.+, Tl.sup.+, K.sup.+, and NH.sub.4.sup.+, and contacting the surface with a second cation-containing solution, the cation being one or more of Cs.sup.+, Rb.sup.+, Ag.sup.+, Tl.sup.+, K.sup.+, and NH.sub.4.sup.+, thereby reducing amounts of radioactive cesium embedded in clays found on the surface.

Index of REMR Technology and Listing of REMR Research Publications

DTIC Science & Technology

1990-10-01

Stitch drilling, CS-MR-1.7 1.15 Underwater, RB-6-5 Vibraspray S-80, RB-2-3 Vehicle mounted breaker, CS-MR- 1.4 Concrete Stain Water jet blasting, CS-MR...Development of Nondestructive Testing AD A191 312 Systems for In Situ Evaluation of Con- crete Structures, by Henry T. Thornton, Jr. and A. Michel...Evaluation of Bird Pest Problems at AD A191 173 U.S. Army Corps of Engineers Civil Works Projects, by Anthony J. Krzysik. 23 REMR Index REMR-EM-3 Oct

Tracking Radionuclide Fractionation in the First Atomic Explosion Using Stable Elements

DOE PAGES

Bonamici, Chloë E.; Hervig, Richard L.; Kinman, William S.

2017-08-25

Compositional analysis of postdetonation fallout is a tool for forensic identification of nuclear devices. However, the relationship between device composition and fallout composition is difficult to interpret because of the complex combination of physical mixing, nuclear reactions, and chemical fractionations that occur in the chaotic nuclear fireball. By using a combination of in situ microanalytical techniques (electron microprobe analysis and secondary ion mass spectrometry), we show that some heavy stable elements (Rb, Sr, Zr, Ba, Cs, Ba, La, Ce, Nd, Sm, Dy, Lu, U, Th) in glassy fallout from the first nuclear test, Trinity, are reliable chemical proxies for radionuclidesmore » generated during the explosion. Stable-element proxies show that radionuclides from the Trinity device were chemically, but not isotopically, fractionated by condensation. Moreover, stable-element proxies delineate chemical fractionation trends that can be used to connect present-day fallout composition to past fireball composition. Stable-element proxies therefore offer a novel approach for elucidating the phenomenology of the nuclear fireball as it relates to the formation of debris and the fixation of device materials within debris.« less

Tracking Radionuclide Fractionation in the First Atomic Explosion Using Stable Elements

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

Bonamici, Chloë E.; Hervig, Richard L.; Kinman, William S.

Compositional analysis of postdetonation fallout is a tool for forensic identification of nuclear devices. However, the relationship between device composition and fallout composition is difficult to interpret because of the complex combination of physical mixing, nuclear reactions, and chemical fractionations that occur in the chaotic nuclear fireball. By using a combination of in situ microanalytical techniques (electron microprobe analysis and secondary ion mass spectrometry), we show that some heavy stable elements (Rb, Sr, Zr, Ba, Cs, Ba, La, Ce, Nd, Sm, Dy, Lu, U, Th) in glassy fallout from the first nuclear test, Trinity, are reliable chemical proxies for radionuclidesmore » generated during the explosion. Stable-element proxies show that radionuclides from the Trinity device were chemically, but not isotopically, fractionated by condensation. Moreover, stable-element proxies delineate chemical fractionation trends that can be used to connect present-day fallout composition to past fireball composition. Stable-element proxies therefore offer a novel approach for elucidating the phenomenology of the nuclear fireball as it relates to the formation of debris and the fixation of device materials within debris.« less

Tracking Radionuclide Fractionation in the First Atomic Explosion Using Stable Elements.

PubMed

Bonamici, Chloë E; Hervig, Richard L; Kinman, William S

2017-09-19

Compositional analysis of postdetonation fallout is a tool for forensic identification of nuclear devices. However, the relationship between device composition and fallout composition is difficult to interpret because of the complex combination of physical mixing, nuclear reactions, and chemical fractionations that occur in the chaotic nuclear fireball. Using a combination of in situ microanalytical techniques (electron microprobe analysis and secondary ion mass spectrometry), we show that some heavy stable elements (Rb, Sr, Zr, Ba, Cs, Ba, La, Ce, Nd, Sm, Dy, Lu, U, Th) in glassy fallout from the first nuclear test, Trinity, are reliable chemical proxies for radionuclides generated during the explosion. Stable-element proxies show that radionuclides from the Trinity device were chemically, but not isotopically, fractionated by condensation. Furthermore, stable-element proxies delineate chemical fractionation trends that can be used to connect present-day fallout composition to past fireball composition. Stable-element proxies therefore offer a novel approach for elucidating the phenomenology of the nuclear fireball as it relates to the formation of debris and the fixation of device materials within debris.

Alkali metals levels in the human brain tissue: Anatomical region differences and age-related changes.

PubMed

Ramos, Patrícia; Santos, Agostinho; Pinto, Edgar; Pinto, Nair Rosas; Mendes, Ricardo; Magalhães, Teresa; Almeida, Agostinho

2016-12-01

The link between trace elements imbalances (both "toxic" and "essential") in the human brain and neurodegenerative disease has been subject of extensive research. More recently, some studies have highlighted the potential role of the homeostasis deregulation of alkali metals in specific brain regions as key factor in the pathogenesis of neurodegenerative diseases such as multiple sclerosis and Alzheimer's disease. Using flame atomic emission spectrometry and inductively coupled plasma-mass spectrometry after microwave-assisted acid digestion of the samples, alkali metals (Na, K, Li, Rb and Cs) were determined in 14 different areas of the human brain (frontal cortex, superior and middle temporal gyri, caudate nucleus, putamen, globus pallidus, cingulated gyrus, hippocampus, inferior parietal lobule, visual cortex of the occipital lobe, midbrain, pons, medulla and cerebellum) of adult individuals (n=42; 71±12, range: 50-101 years old) with no known history and evidence of neurodegenerative, neurological or psychiatric disorder. Potassium was found as the most abundant alkali metal, followed by Na, Rb, Cs and Li. Lithium, K and Cs distribution showed to be quite heterogeneous. On the contrary, Rb and Na appeared quite homogeneously distributed within the human brain tissue. The lowest levels of Na, K, Rb and Li were found in the brainstem (midbrain, medulla and pons) and cerebellum, while the lowest levels of Cs were found in the frontal cortex. The highest levels of K (mean±sd; range 15.5±2.5; 8.9-21.8mg/g) Rb (17.2±6.1; 3.9-32.4μg/g and Cs (83.4±48.6; 17.3-220.5ng/g) were found in putamen. The highest levels of Na and Li were found in the frontal cortex (11.6±2.4; 6.6-17.1mg/g) and caudate nucleus (7.6±4.6 2.2-21.3ng/g), respectively. Although K, Cs and Li levels appear to remain largely unchanged with age, some age-related changes were observed for Na and Rb levels in particular brain regions (namely in the hippocampus). Copyright © 2016 Elsevier GmbH. All rights reserved.

Concentration of stable elements in food products

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

Montford, M.A.; Shank, K.E.; Hendricks, C.

1980-01-01

Food samples were taken from commercial markets and analyzed for stable element content. The concentrations of most stable elements (Ag, Al, As, Au, Ba, Br, Ca, Ce, Cl, Co, Cr, Cs, Cu, Fe, Hf, I, K, La, Mg, Mn, Mo, Na, Rb, Sb, Sc, Se, Sr, Ta, Th, Ti, V, Zn, Zr) were determined using multiple-element neutron activation analysis, while the concentrations of other elements (Cd, Hg, Ni, Pb) were determined using atomic absorption. The relevance of the concentrations found are noted in relation to other literature values. An earlier study was extended to include the determination of the concentrationmore » of stable elements in home-grown products in the vicinity of the Oak Ridge National Laboratory. Comparisons between the commercial and local food-stuff values are discussed.« less

Spectroscopic and structural studies of a new para-iodo-N-benzyl amide of salinomycin

NASA Astrophysics Data System (ADS)

Antoszczak, Michał; Janczak, Jan; Rutkowski, Jacek; Brzezinski, Bogumił; Huczyński, Adam

2017-11-01

A new para-iodo-N-benzyl amide of salinomycin was synthesized and characterized by NMR, FT-IR, DFT, single crystal X-ray diffraction and theoretical methods. The results obtained for the crystal, in solution and in gas phase provided evidence of pseudo-cyclic structure of this compound stabilized by intramolecular hydrogen bonds. It was shown that the compound studied forms stable 1:1 complexes with monovalent (Li+, Na+, K+, Rb+ and Cs+) and divalent (Mg2+, Ca2+, Sr2+ and Ba2+) cations demonstrating that the chemical modification of salinomycin carboxyl group considerably changes the ionophoretic properties of this antibiotic. For the first time, the ESI MS fragmentations of the complex of para-iodo-N-benzyl amide of salinomycin with Na+ are also discussed in details.

Ternary oxide nanostructures and methods of making same

DOEpatents

Wong, Stanislaus S [Stony Brook, NY; Park, Tae-Jin [Port Jefferson, NY

2009-09-08

A single crystalline ternary nanostructure having the formula A.sub.xB.sub.yO.sub.z, wherein x ranges from 0.25 to 24, and y ranges from 1.5 to 40, and wherein A and B are independently selected from the group consisting of Ag, Al, As, Au, B, Ba, Br, Ca, Cd, Ce, Cl, Cm, Co, Cr, Cs, Cu, Dy, Er, Eu, F, Fe, Ga, Gd, Ge, Hf, Ho, I, In, Ir, K, La, Li, Lu, Mg, Mn, Mo, Na, Nb, Nd, Ni, Os, P, Pb, Pd, Pr, Pt, Rb, Re, Rh, Ru, S, Sb, Sc, Se, Si, Sm, Sn, Sr, Ta, Tb, Tc, Te, Ti, Tl, Tm, U, V, W, Y, Yb, and Zn, wherein the nanostructure is at least 95% free of defects and/or dislocations.

Four new chalcohalides, NaBa{sub 2}SnS{sub 4}Cl, KBa{sub 2}SnS{sub 4}Cl, KBa{sub 2}SnS{sub 4}Br and CsBa{sub 2}SnS{sub 4}Cl: Syntheses, crystal structures and optical properties

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

Li, Chao; Feng, Kai; Tu, Heng

Four new chalcohalides, namely NaBa{sub 2}SnS{sub 4}Cl, KBa{sub 2}SnS{sub 4}Cl, KBa{sub 2}SnS{sub 4}Br, and CsBa{sub 2}SnS{sub 4}Cl, have been synthesized by the conventional high temperature solid-state reactions. They crystallize in three different space groups: space group I4/mcm for NaBa{sub 2}SnS{sub 4}Cl and KBa{sub 2}SnS{sub 4}Cl, Pnma for KBa{sub 2}SnS{sub 4}Br, and P2{sub 1}/c for CsBa{sub 2}SnS{sub 4}Cl. In all four compounds, the X{sup −} halide anions are only connected to six alkali metal or Ba cations, and the Sn atoms are only tetrahedrally enjoined to four S atoms. However, the M–X–Ba pseudo layers and the SnS{sub 4} tetrahedra are arrangedmore » in different ways in the three structural types, which demonstrates the interesting effect of ionic radii on the crystal structures. UV–vis–NIR spectroscopy measurements indicate that NaBa{sub 2}SnS{sub 4}Cl, KBa{sub 2}SnS{sub 4}Cl, KBa{sub 2}SnS{sub 4}Br, and CsBa{sub 2}SnS{sub 4}Cl have band gaps of 2.28, 2.30, 1.95, and 2.06 eV, respectively. - Graphical abstract: A new series of chalcohalides, NaBa{sub 2}SnS{sub 4}Cl, KBa{sub 2}SnS{sub 4}Cl, KBa{sub 2}SnS{sub 4}Br and CsBa{sub 2}SnS{sub 4}Cl have been obtained. They present three different space groups: NaBa{sub 2}SnS{sub 4}Cl and KBa{sub 2}SnS{sub 4}Cl in space group I4/mcm, KBa{sub 2}SnS{sub 4}Br in Pnma and CsBa{sub 2}SnS{sub 4}Cl in space group P2{sub 1}/c. UV–vis–NIR spectroscopy measurements indicate that NaBa{sub 2}SnS{sub 4}Cl, KBa{sub 2}SnS{sub 4}Cl, KBa{sub 2}SnS{sub 4}Br and CsBa{sub 2}SnS{sub 4}Cl have band gaps of 2.28, 2.30 1.95, and 2.06 eV, respectively. - Highlights: • Four new chalcohalides, NaBa{sub 2}SnS{sub 4}Cl, KBa{sub 2}SnS{sub 4}Cl, KBa{sub 2}SnS{sub 4}Br and CsBa{sub 2}SnS{sub 4}Cl were obtained. • They adopt three different structures owing to different ionic radii and elemental electronegativity. • NaBa{sub 2}SnS{sub 4}Cl, KBa{sub 2}SnS{sub 4}Cl, KBa{sub 2}SnS{sub 4}Br and CsBa{sub 2}SnS{sub 4}Cl have band gaps of 2.28, 2.30 1.95, and 2.06 eV, respectively.« less

Structural diversities induced by cation sizes in a series of fluorogermanophosphates: A2[GeF2(HPO4)2] (A = Na, K, Rb, NH4, and Cs).

PubMed

Chen, Zhang-Gai; Huang, Xia; Zhuang, Rong-Chuan; Zhang, Yu; Liu, Xin; Shi, Tao; Wang, Shuai-Hua; Wu, Shao-Fan; Mi, Jin-Xiao; Huang, Ya-Xi

2017-09-12

Germanophosphates, in comparison with other metal phosphates, have been less studied but potentially exhibit more diverse structural chemistry with wide applications. Herein we applied a hydro-/solvo-fluorothermal route to make use of both the "tailor effect" of fluoride for the formation of low dimensional anionic clusters and the presence of alkali cations of different sizes to align the anionic clusters to control the overall crystal symmetries of germanophosphates. The synergetic effects of fluoride and alkali cations led to structural changes from chain-like structures to layered structures in a series of five novel fluorogermanophosphates: A 2 [GeF 2 (HPO 4 ) 2 ] (A = Na, K, Rb, NH 4 , and Cs, denoted as Na, K, Rb, NH4, and Cs). Although these fluorogermanophosphates have stoichiometrically equivalent formulas, they feature different anionic clusters, diverse structural dimensionalities, and contrasting crystal symmetries. Chain-like structures were observed for the compounds with the smaller sized alkali ions (Na + , K + , and Rb + ), whereas layered structures were found for those containing the larger sized cations ((NH 4 ) + and Cs + ). Specifically, monoclinic space groups were observed for the Na, K, Rb, and NH4 compounds, whereas a tetragonal space group P4/mbm was found for the Cs compound. These compounds provide new insights into the effects of cation sizes on the anionic clusters built from GeO 4 F 2 octahedra and HPO 4 tetrahedra as well as their influences on the overall structural symmetries in germanophosphates. Further characterization including IR spectroscopy and thermal analyses for all five compounds is also presented.

Selective reflection of laser radiation from submicron layers of Rb and Cs atomic vapors: Applications in atomic spectroscopy

NASA Astrophysics Data System (ADS)

Klinger, E.; Sargsyan, A.; Leroy, C.; Sarkisyan, D.

2017-10-01

We studied selective reflection (SR) of laser radiation from a window of a nanocell with thickness L λ 1,2/2 filled with Rb and Cs atoms, where λ 1 = 780 nm and λ 2 = 852 nm are the wavelengths resonant with the D 2 laser lines for Rb and Cs, respectively. It is demonstrated that the negative derivative of the SR signal profile for L > λ/2 changes to the positive one for L < λ/2. It is shown that the real-time formation of the SR signal profile derivative (SRD) with the spectral width 30-40 MHz and located at the atomic transition is, in particular, a convenient frequency marker of D 2 transitions in Rb and Cs. The amplitudes of SRD signals are proportional to the atomic transition probabilities. A comparison with the known saturated absorption (SA) method demonstrated a number of advantages, such as the absence of cross-over resonances in the SRD spectrum, the simplicity of realization, a low required power, etc. An SRD frequency marker also operates in the presence of the Ne buffer gas at a pressure of 6 Torr, which allowed us to determine the Ne-Rb collisional broadening, whereas the SA method is already inapplicable at buffer gas pressures above 0.1 Torr. The realization simplicity makes the SRD method a convenient tool for atomic spectroscopy. Our theoretical model well describes the SRD signal.

Penetration of alkali atoms throughout a graphene membrane: theoretical modeling

NASA Astrophysics Data System (ADS)

Boukhvalov, D. W.; Virojanadara, C.

2012-02-01

Theoretical studies of penetration of various alkali atoms (Li, Na, Rb, Cs) throughout a graphene membrane grown on a silicon carbide substrate are reported and compared with recent experimental results. Results of first principles modeling demonstrate a rather low (about 0.8 eV) energy barrier for the formation of temporary defects in the carbon layer required for the penetration of Li at a high concentration of adatoms, a higher (about 2 eV) barrier for Na, and barriers above 4 eV for Rb and Cs. Experiments prove migration of lithium adatoms from the graphene surface to the buffer layer and SiC substrate at room temperature, sodium at 100 °C and impenetrability of the graphene membrane for Rb and Cs. Differences between epitaxial and free-standing graphene for the penetration of alkali ions are also discussed.

Penetration of alkali atoms throughout a graphene membrane: theoretical modeling.

PubMed

Boukhvalov, D W; Virojanadara, C

2012-03-07

Theoretical studies of penetration of various alkali atoms (Li, Na, Rb, Cs) throughout a graphene membrane grown on a silicon carbide substrate are reported and compared with recent experimental results. Results of first principles modeling demonstrate a rather low (about 0.8 eV) energy barrier for the formation of temporary defects in the carbon layer required for the penetration of Li at a high concentration of adatoms, a higher (about 2 eV) barrier for Na, and barriers above 4 eV for Rb and Cs. Experiments prove migration of lithium adatoms from the graphene surface to the buffer layer and SiC substrate at room temperature, sodium at 100 °C and impenetrability of the graphene membrane for Rb and Cs. Differences between epitaxial and free-standing graphene for the penetration of alkali ions are also discussed.

Elimination of reactive blue 4 from aqueous solutions using 3-aminopropyl triethoxysilane modified chitosan beads.

PubMed

Vakili, Mohammadtaghi; Rafatullah, Mohd; Salamatinia, Babak; Ibrahim, Mahamad Hakimi; Abdullah, Ahmad Zuhairi

2015-11-05

The adsorption behavior of chitosan (CS) beads modified with 3-aminopropyl triethoxysilane (APTES) for the removal of reactive blue 4 (RB4) in batch studies has been investigated. The effects of modification conditions, such as the APTES concentration, temperature and reaction time on RB4 removal, were studied. The adsorbent prepared at a concentration of 2 wt% APTES for 8h at 50 °C was the most effective one for RB4 adsorption. The adsorption capacity of modified CS beads (433.77 mg/g) was 1.37 times higher than that of unmodified CS beads (317.23 mg/g). The isotherm data are adequately described by a Freundlich model, and the kinetic study revealed that the pseudo-second-order rate model was in better agreement with the experimental data. The negative values of the thermodynamic parameters, including ΔG° (-2.28 and -4.70 kJ/mol at 30 ± 2 °C), ΔH° (-172.18 and -43.82 kJ/mol) and ΔS° (-560.71 and -129.08 J/mol K) for CS beads and APTES modified beads, respectively, suggest that RB4 adsorption is a spontaneous and exothermic process. Copyright © 2015 Elsevier Ltd. All rights reserved.

Trace element behavior in hydrothermal experiments: Implications for fluid processes at shallow depths in subduction zones

NASA Astrophysics Data System (ADS)

You, C.-F.; Castillo, P. R.; Gieskes, J. M.; Chan, L. H.; Spivack, A. J.

1996-05-01

Chemical evaluation of fluids affected during progressive water-sediment interactions provides critical information regarding the role of slab dehydration and/or crustal recycling in subduction zones. To place some constraints on geochemical processes during sediment subduction, reactions between décollement sediments and synthetic NaCl-CaCl 2 solutions at 25-350°C and 800 bar were monitored in laboratory hydrothermal experiments using an autoclave apparatus. This is the first attempt in a single set of experiments to investigate the relative mobilities of many subduction zone volatiles and trace elements but, because of difficulties in conducting hydrothermal experiments on sediments at high P-T conditions, the experiments could only be designed for a shallow (˜ 10 km) depth. The experimental results demonstrate mobilization of volatiles (B and NH 4) and incompatible elements (As, Be, Cs, Li, Pb, Rb) in hydrothermal fluids at relatively low temperatures (˜ 300°C). In addition, a limited fractionation of light from heavy rare earth elements (REEs) occurs under hydrothermal conditions. On the other hand, the high field strength elements (HFSEs) Cr, Hf, Nb, Ta, Ti, and Zr are not mobile in the reacted fluids. The observed behavior of volatiles and trace elements in hydrothermal fluids is similar to the observed enrichment in As, B, Cs, Li, Pb, Rb, and light REEs and depletion in HFSEs in arc magmas relative to magmas derived directly from the upper mantle. Thus, our work suggests a link between relative mobilities of trace elements in hydrothermal fluids and deep arc magma generation in subduction zones. The experimental results are highly consistent with the proposal that the addition of subduction zone hydrous fluids to the subarc mantle, which has been depleted by previous melting events, can produce the unique characteristics of arc magmas. Moreover, the results suggest that deeply subducted sediments may no longer have the composition necessary to generate the other distinct characteristics, such as the B-δ 11 B and B- 10Be systematics, of arc lavas. Finally, the mobilization of B, Cs, Pb, and light REEs relative to heavy REEs in the hydrothermal fluids fractionate the ratios of B/Be, B/Nb, Cs/Rb, Pb/Ce, La/Ba and LREE/HREE, which behave conservatively during normal magmatic processes. These results demonstrate that the composition of slab-derived fluids has great implications for the recycling of elements; not only in arc magmas but also in mantle plumes.

Expression and permeation properties of the K(+) channel Kir7.1 in the retinal pigment epithelium.

PubMed

Shimura, M; Yuan, Y; Chang, J T; Zhang, S; Campochiaro, P A; Zack, D J; Hughes, B A

2001-03-01

Bovine Kir7.1 clones were obtained from a retinal pigment epithelium (RPE)-subtracted cDNA library. Human RPE cDNA library screening resulted in clones encoding full-length human Kir7.1. Northern blot analysis indicated that bovine Kir7.1 is highly expressed in the RPE. Human Kir7.1 channels were expressed in Xenopus oocytes and studied using the two-electrode voltage-clamp technique. The macroscopic Kir7.1 conductance exhibited mild inward rectification and an inverse dependence on extracellular K+ concentration ([K+]o). The selectivity sequence based on permeability ratios was K+ (1.0) approximately Rb+ (0.89) > Cs+ (0.013) > Na+ (0.003) approximately Li+ (0.001) and the sequence based on conductance ratios was Rb+ (9.5) > K+ (1.0) > Na+ (0.458) > Cs+ (0.331) > Li+ (0.139). Non-stationary noise analysis of Rb+ currents in cell-attached patches yielded a unitary conductance for Kir7.1 of approximately 2 pS. In whole-cell recordings from freshly isolated bovine RPE cells, the predominant current was a mild inwardly rectifying K+ current that exhibited an inverse dependence of conductance on [K+]o. The selectivity sequence based on permeability ratios was K+ (1.0) approximately Rb+ (0.89) > Cs+ (0.021) > Na+ (0.003) approximately Li+ (0.002) and the sequence based on conductance ratios was Rb+ (8.9) > K+ (1.0) > Na+ (0.59) > Cs+ (0.23) > Li+ (0.08). In cell-attached recordings with Rb+ in the pipette, inwardly rectifying currents were observed in nine of 12 patches of RPE apical membrane but in only one of 13 basolateral membrane patches. Non-stationary noise analysis of Rb+ currents in cell-attached apical membrane patches yielded a unitary conductance for RPE Kir of approximately 2 pS. On the basis of this molecular and electrophysiological evidence, we conclude that Kir7.1 channel subunits comprise the K+ conductance of the RPE apical membrane.

Facile synthesis and structure characterization of hexagonal tungsten bronzes crystals

NASA Astrophysics Data System (ADS)

Lee, Jiann-Shing; Liu, Hao-Chuan; Peng, Gao-De; Tseng, Yawteng

2017-05-01

A facile molten-salt route was used to synthesize hexagonal Cs0.33WO3, Rb0.33WO3 and K0.30WO3 crystals. The three isostructural compounds were successfully prepared from the reaction of MxWO3 powders (M = Cs, Rb, K) in the CsCl/NaCl, RbCl/NaCl and KCl/NaCl fluxes, respectively. The structure determination and refinement, based on single-crystal X-ray diffraction data, are in agreement with previous works, possessing space group P63/mcm. The a and c parameters vary non-linearly with increasing radii of the M+ cations (rM) that is coordinated to twelve oxygen atoms. Both the volumes of unit-cell and WO6 octahedra vary linearly with rM, which become smaller from Cs0.33WO3 to K0.30WO3. The distortion of WO6 octahedra as well as isotropic displacement parameters increases from Cs0.33WO3 to K0.30WO3. The geometry of the WO6 octahedron becomes more regular with increasing rM. These structural trends arise from the effective size of the M+ cation.

Modifier cation effects on 29Si nuclear shielding anisotropies in silicate glasses

NASA Astrophysics Data System (ADS)

Baltisberger, Jay H.; Florian, Pierre; Keeler, Eric G.; Phyo, Pyae A.; Sanders, Kevin J.; Grandinetti, Philip J.

2016-07-01

We have examined variations in the 29Si nuclear shielding tensor parameters of SiO4 tetrahedra in a series of seven alkali and alkaline earth silicate glass compositions, Cs2O · 4.81 SiO2, Rb2O · 3.96 SiO2, Rb2O · 2.25 SiO2, K2O · 4.48 SiO2, Na2O · 4.74 SiO2, BaO · 2.64 SiO2, and SrO · 2.36 SiO2, using natural abundance 29Si two-dimensional magic-angle flipping (MAF) experiments. Our analyses of these 2D spectra reveal a linear dependence of the 29Si nuclear shielding anisotropy of Q(3) sites on the Si-non-bridging oxygen bond length, which in turn depends on the cation potential and coordination of modifier cations to the non-bridging oxygen. We also demonstrate how a combination of Cu2+ as a paramagnetic dopant combined with echo train acquisition can reduce the total experiment time of 29Si 2D NMR measurements by two orders of magnitude, enabling higher throughput 2D NMR studies of glass structure.

Modifier cation effects on (29)Si nuclear shielding anisotropies in silicate glasses.

PubMed

Baltisberger, Jay H; Florian, Pierre; Keeler, Eric G; Phyo, Pyae A; Sanders, Kevin J; Grandinetti, Philip J

2016-07-01

We have examined variations in the (29)Si nuclear shielding tensor parameters of SiO4 tetrahedra in a series of seven alkali and alkaline earth silicate glass compositions, Cs2O·4.81 SiO2, Rb2O·3.96 SiO2, Rb2O·2.25 SiO2, K2O·4.48 SiO2, Na2O·4.74 SiO2, BaO·2.64 SiO2, and SrO·2.36 SiO2, using natural abundance (29)Si two-dimensional magic-angle flipping (MAF) experiments. Our analyses of these 2D spectra reveal a linear dependence of the (29)Si nuclear shielding anisotropy of Q((3)) sites on the Si-non-bridging oxygen bond length, which in turn depends on the cation potential and coordination of modifier cations to the non-bridging oxygen. We also demonstrate how a combination of Cu(2+) as a paramagnetic dopant combined with echo train acquisition can reduce the total experiment time of (29)Si 2D NMR measurements by two orders of magnitude, enabling higher throughput 2D NMR studies of glass structure. Copyright © 2016 Elsevier Inc. All rights reserved.

Physical and antimicrobial properties of starch-carboxy methyl cellulose film containing rosemary essential oils encapsulated in chitosan nanogel.

PubMed

Mohsenabadi, Nafiseh; Rajaei, Ahmad; Tabatabaei, Meisam; Mohsenifar, Afshin

2018-06-01

This study was set to prepare a new active film by using a biodegradable bio-based source, i.e., corn starch. To achieve that, benzoic acid (BA) and chitosan (CS) were covalently bound and CS-BA nanogel was then obtained using self-assembly method. Subsequently, rosemary essential oil (REO) was encapsulated in CS-BA nanogel. Finally, REO in both free and encapsulated forms were incorporated in starch-carboxy methyl cellulose (CMC) films and their physical, mechanical and antimicrobial properties were studied. The films incorporating CS-BA nanogel had a higher water vapor permeability compared with the films containing REO. Moreover, film containing 0.2% CS-BA nanogel had the highest transparency and tensile strength. The REO and nanogel alone had inhibitory effects against Staphylococcus aureus (S. aureus) and by encapsulation, the inhibitory effect of REO was increased. By encapsulating REO in nanogel, both immediately (REO) and gradual (Nanogel) antimicrobial effect against S. aureus in the starch-CMC suspensions were obtained. Copyright © 2018 Elsevier B.V. All rights reserved.

Dopamine-induced changes in neural network patterns supporting aversive conditioning.

PubMed

Diaconescu, Andreea Oliviana; Menon, Mahesh; Jensen, Jimmy; Kapur, Shitij; McIntosh, Anthony Randal

2010-02-08

The aim of the present paper is to assess the effects of altered dopamine (DA) transmission on the functional connectivity among brain regions mediating aversive conditioning in humans. To this aim, we analyzed a previous published data set from a double-blind design combined with functional magnetic resonance imaging (fMRI) recordings in which healthy volunteers were randomly assigned to one of three drug groups: amphetamine (an indirect DA agonist), haloperidol (DA D2 receptor antagonist), and placebo. Participants were exposed to an aversive classical conditioning paradigm using cutaneous electrical stimulation as the unconditioned stimulus (US), and visual cues as the conditioned stimuli (CS) where one colour (CS+) was followed by the US in 33% of the trials and another colour (CS-) had no consequences. All participants reported awareness of stimulus contingencies. Group analysis of fMRI data revealed that the left ventral striatum (VS) and amygdala activated in response to the CS+ in all the three groups. Because of their activation patterns and documented involvement in aversive conditioning, both regions were used as seeds in the functional connectivity analysis. To constrain the functional networks obtained to relate to the conditioned response, we also correlated seed activity with the Galvanic Skin Response (GSR). In the placebo group, the right ventral tegmental area/substantia nigra (VTA/SN), bilateral caudate, right parahippocampal gyrus, left inferior parietal lobule (IPL), bilateral postcentral gyrus, bilateral middle frontal (BA 46), orbitofrontal, and ventromedial prefrontal cortices (PFC, BA 10/11) correlated with the VS and amygdala seeds in response to the CS+ compared to the CS-. Enhancing dopamine transmission via amphetamine was associated with reduced task differences and significant functional connectivity for both CS+ and CS- conditions between the left VS seed and regions modulated by DA, such as the left VTA/SN, right caudate, left amygdala, left middle frontal gyrus (BA 46), and bilateral ventromedial PFC (BA 10). Blocking dopamine transmission via haloperidol was associated with significant functional connectivity across an alternate network of regions including the left amygdala seed and the right insula, the left ACC (BA 24/32), bilateral IPL (BA 40), precuneus (BA 7), post-central gyrus, middle frontal gyrus (BA 46), and supplementary motor area (SMA, BA 6) to the CS+ versus the CS-. These data provide insight into the distinct effects of DA agents on the functional connectivity between striatal, limbic, and prefrontal areas. Copyright 2009 Elsevier B.V. All rights reserved.

(Ag{sub 2}TeS{sub 3}){sub 2} {small_bullet} A{sub 2}S{sub 6} (A = Rb, Cs) : layers of silver thiotellurite intergrown with alkali-metal polysulfides.

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

Nguyen, S. L.; Jang, J. I.; Ketterson, J. B.

2010-09-22

The layered compounds RbAg{sub 2}TeS{sub 6} and CsAg{sub 2}TeS{sub 6} crystallize in the noncentrosymmetric space group P6{sub 3}cm, with a = 19.15 {angstrom}, c = 14.64 {angstrom}, and V = 4648 {angstrom}{sup 3} and a = 19.41 {angstrom}, c = 14.84 {angstrom}, and V = 4839 {angstrom}{sup 3}, respectively. The structures are composed of neutral [Ag{sub 2}TeS{sub 3}] layers alternating with charge-balanced salt layers containing polysulfide chains of [S{sub 6}]{sup 2-} and alkali-metal ions. RbAg{sub 2}TeS{sub 6} and CsAg{sub 2}TeS{sub 6} are air- and water-stable, wide-band-gap semiconductors (E{sub g} {approx} 2.0 eV) exhibiting nonlinear-optical second-harmonic generation.

Study of activation cross sections of deuteron induced reactions on barium. Production of 131Cs, 133Ba

NASA Astrophysics Data System (ADS)

Tárkányi, F.; Hermanne, A.; Ditrói, F.; Takács, S.; Szücs, Z.; Brezovcsik, K.

2018-01-01

In the frame of a systematic study of deuteron induced activation processes on middle mass elements, excitation functions of the natBa(d,x) 135,133,132La, 135m,133m,133mg,131mgBa, 136mg,134mg,132,129Cs reactions were measured up to 50 MeV for the first time. Cross sections were measured with the activation method using a stacked foil irradiation technique followed by HPGe γ-ray spectrometry. A comparison with the results of the nuclear model TALYS code (reported in the TENDL-2015 library) was done. The potential use of the deuteron induced reactions on Ba for applications (131Cs and 131Ba production) is discussed.

Composition of island arcs and continental growth.

NASA Technical Reports Server (NTRS)

Jakes, P.; White, A. J. R.

1971-01-01

Island arc volcanism has contributed and is still contributing to continental growth, but the composition of island arcs differs from that of the upper continental crust in its lower abundance of Si, K, Rb, Ba, Sr and light rare earth elements. In their advanced stage of evolution, island arcs contain more than 80% of tholeiitic and 15% of ?island arc' calc-alkaline rocks with varied SiO2 contents. The larger proportion of tholeiitic rocks is in the lower crustal levels. The high stratigraphical levels of the island arcs are composed of tholeiitic plus calc-alkaline and/or high potash (shoshonitic) associations with higher abundances of K, Rb, Sr, and Ba. Stratification of the island arc crust is accentuated by another type of calc-alkaline volcanism (Andean type) originating at a late stage of arc evolution, probably by partial melting at the base of the crust. This causes enrichment of the upper crust in K, Rb, Ba and REE and accounts for upper crustal abundances of these elements as well as of SiO2.

Metallic elements and metalloids in Boletus luridus, B. magnificus and B. tomentipes mushrooms from polymetallic soils from SW China.

PubMed

Falandysz, Jerzy; Zhang, Ji; Wiejak, Anna; Barałkiewicz, Danuta; Hanć, Anetta

2017-08-01

Yunnan Province in China is known for its high biodiversity of mushrooms and a diverse geochemistry of soil bedrock and polymetallic soils, but our knowledge of mineral compositions of mushrooms from Yunnan is scarce. The metallic trace elements, Ag, Ba, Co, Cd, Cs, Cu, Cr, Hg, Li, Mn, Ni, Pb, Rb, Sr, V, Tl, U and Zn, and the metalloids, As and Sb, have been investigated using validated methods with a dynamic reactive cell by mass spectroscopy - inductive coupled plasma and cold vapour - atomic absorption spectroscopy on three popular species of Boletus mushrooms from Southwestern China. The trace mineral profiles in caps and stipes of B. luridus (24 individuals), B. magnificus (29 individuals) and B. tomentipes (38 individuals) have been evaluated. The interspecific differences in the content of several trace elements could be attributed to known differences in the geochemistry of soils in Yunnan, but for copper a difference was observed within species. The mean values of concentrations in composite samples of caps for B. luridus, B. magnificus and B. tomentipes from three to four locations were at the ranges (mgkg -1 dry biomass): Ag (1.3-3.7), As (0.79-53), Ba (4.0-12), Co (0.68-1.2), Cd (0.79-2.2), Cs (0.67-55), Cu (37-77), Cr (5.0-7.6), Hg (2.1-5.4), Li (0.15-0.61), Mn (13-28), Ni (0.86-4.6), Pb (0.59-1.8), Rb (90-120), Sb (0.014-0.088), Sr (0.63-1.6), V (1.4-2.2), Tl (0.017-0.054), U (0.029-0.065) and Zn (130-180). Caps of Boletus mushrooms were richer in Ag, Cu, Hg and Zn than stipes, while other elements were distributed roughly equally between both morphological parts. B. luridus, B. magnificus and B. tomentipes grew in certain sites in Yunnan contained Ag, As, Ba, Cr, Hg, Ni, Sr or V at elevated concentration. A specific geochemistry of the soils type (latosols, lateritic red earths, and red and yellow earths in the Circum-Pacific Mercuriferous Belt of Southwestern China) can explain occurrence of some minerals at greater or elevated amount in mushrooms in Yunnan, while number of available research and data on mineral composition of mushrooms due to geochemical anomalies of soil parent material is so far little. Copyright © 2017 Elsevier Inc. All rights reserved.

Bond-length distributions for ions bonded to oxygen: alkali and alkaline-earth metals.

PubMed

Gagné, Olivier Charles; Hawthorne, Frank Christopher

2016-08-01

Bond-length distributions have been examined for 55 configurations of alkali-metal ions and 29 configurations of alkaline-earth-metal ions bonded to oxygen, for 4859 coordination polyhedra and 38 594 bond distances (alkali metals), and for 3038 coordination polyhedra and 24 487 bond distances (alkaline-earth metals). Bond lengths generally show a positively skewed Gaussian distribution that originates from the variation in Born repulsion and Coulomb attraction as a function of interatomic distance. The skewness and kurtosis of these distributions generally decrease with increasing coordination number of the central cation, a result of decreasing Born repulsion with increasing coordination number. We confirm the following minimum coordination numbers: ([3])Li(+), ([3])Na(+), ([4])K(+), ([4])Rb(+), ([6])Cs(+), ([3])Be(2+), ([4])Mg(2+), ([6])Ca(2+), ([6])Sr(2+) and ([6])Ba(2+), but note that some reported examples are the result of extensive dynamic and/or positional short-range disorder and are not ordered arrangements. Some distributions of bond lengths are distinctly multi-modal. This is commonly due to the occurrence of large numbers of structure refinements of a particular structure type in which a particular cation is always present, leading to an over-representation of a specific range of bond lengths. Outliers in the distributions of mean bond lengths are often associated with anomalous values of atomic displacement of the constituent cations and/or anions. For a sample of ([6])Na(+), the ratio Ueq(Na)/Ueq(bonded anions) is partially correlated with 〈([6])Na(+)-O(2-)〉 (R(2) = 0.57), suggesting that the mean bond length is correlated with vibrational/displacement characteristics of the constituent ions for a fixed coordination number. Mean bond lengths also show a weak correlation with bond-length distortion from the mean value in general, although some coordination numbers show the widest variation in mean bond length for zero distortion, e.g. Li(+) in [4]- and [6]-coordination, Na(+) in [4]- and [6]-coordination. For alkali-metal and alkaline-earth-metal ions, there is a positive correlation between cation coordination number and the grand mean incident bond-valence sum at the central cation, the values varying from 0.84 v.u. for ([5])K(+) to 1.06 v.u. for ([8])Li(+), and from 1.76 v.u. for ([7])Ba(2+) to 2.10 v.u. for ([12])Sr(2+). Bond-valence arguments suggest coordination numbers higher than [12] for K(+), Rb(+), Cs(+) and Ba(2+).

High sensitivity in-situ analysis of light lithophile (Li, Be, B) and alkali (Rb, Cs) elements by laser ablation magnetic sector ICP-MS: application to back arc basin magmatism

NASA Astrophysics Data System (ADS)

Kent, A. J.; Ungerer, C. A.

2003-12-01

Light lithophile (B, Be, Li) and alkali elements (Rb, Cs) provide many constraints on the origin and evolution of primitive magmatic rocks. However these elements are often present at low abundances, requiring large sample volumes, and may be strongly effected by alteration or sample contamination. We have developed a technique for rapid, in-situ, analysis of B, Be, Li, Rb and Cs abundances in glasses, glass inclusions and minerals using laser ablation microsampling and analysis by magnetic sector ICP-MS. By coupling the high sensitivity, dynamic range and low backgrounds of the ICP-MS with the speed and minimal sample preparation requirements of laser ablation, we can analyze these elements with detection limits that rival many solution-based techniques in ~60 s and using << 200 ng of material. Analyses are conducted using a NewWave DUV 193 nm ArF Excimer laser system, with He carrier gas. Samples were ablated at energies of 10-12 mJ/cm2 with pulse rates between 2-5 hz, and by either translating a 50 μ m laser spot over the surface at a rate of 5 μ m/s or by maintaining a stationary 50-70 μ m spot. Ablated material was analyzed with a VG Axiom single collector ICP-MS using a high-sensitivity sampler cone. All peaks were checked at high mass resolving power for molecular interferences, and analyses were conducted at low resolving power to maximize transmission. Careful monitoring of backgrounds was required for low-abundance measurements. Calculated detection limits are 1-2 ppb (Cs, Be), 5-10 ppb (Li) and 15-20 ppb (B, Rb). Surface contamination was removed with a pre-analysis ablation pass, and the small size of the laser spot allowed us to avoid altered and devitrified areas. Analysis of standard glasses showed excellent agreement with accepted values and repeat analyses suggest external errors are typically < 5-10%. Glasses from the Lau Basin show strong enrichments in B, Rb and Cs that correlate with a slab-fluid signature. B, Be Rb and Cs contents are very low in MORB-like samples from the north of the basin but are enriched in evolved lavas from propagating ridge tips.

Chemical characterization of gas- and oil-bearing shales by instrumental neutron activation analysis

USGS Publications Warehouse

Frost, J.K.; Koszykowski, R.F.; Klemm, R.C.

1982-01-01

The concentration of As, Ba, Ca, Co, Cr, Cs, Dy, Eu, Fe, Ga, Hf, K, La, Lu, Mn, Mo, Na, Ni, Rb, Sb, Sc, Se, Sm, Sr, Ta, Tb, Th, U, Yb, and Zn were determined by instrumental neutron activation analysis in block shale samples of the New Albany Group (Devonian-Mississippian) in the in the Illinois Basin. Uranium content of the samples was as high as 75 ppm and interfered in the determination of samarium, molybdenum, barium and cerium. In the determination of selenium a correction was made for interference from tantalum. U, As, Co, Mo, Ni and Sb as well as Cu, V and pyritic sulphur which were determined by other methods, were found to correlate positively with the organic carbon content of the samples. ?? 1982 Akade??miai Kiado??.

Characterization of ancient glass excavated in Enez (Ancient Ainos) Turkey by combined Instrumental Neutron Activation Analysis and Fourier Transform Infrared spectrometry techniques

NASA Astrophysics Data System (ADS)

Akyuz, Sevim; Akyuz, Tanil; Mukhamedshina, Nuranya M.; Mirsagatova, A. Adiba; Basaran, Sait; Cakan, Banu

2012-05-01

Ancient glass fragments excavated in the archaeological district Enez (Ancient Ainos)-Turkey were investigated by combined Instrumental Neutron Activation Analysis (INAA) and Fourier Transform Infrared (FTIR) spectrometry techniques. Multi-elemental contents of 15 glass fragments that belong to Hellenistic, Roman, Byzantine, and Ottoman Periods, were determined by INAA. The concentrations of twenty six elements (Na, K, Ca, Sc, Cr, Mn, Fe, Co, Cu, Zn, As, Rb, Sr, Sb, Cs, Ba, Ce, Sm, Eu, Tb, Yb, Lu, Hf, Ta, Au and Th), which might be present in the samples as flux, stabilizers, colorants or opacifiers, and impurities, were examined. Chemometric treatment of the INAA data was performed and principle component analysis revealed presence of 3 distinct groups. The thermal history of the glass samples was determined by FTIR spectrometry.

Observation of New Neutron-rich Isotopes among Fission Fragments from In-flight Fission of 345 MeV/nucleon 238U: Search for New Isotopes Conducted Concurrently with Decay Measurement Campaigns

NASA Astrophysics Data System (ADS)

Shimizu, Yohei; Kubo, Toshiyuki; Fukuda, Naoki; Inabe, Naohito; Kameda, Daisuke; Sato, Hiromi; Suzuki, Hiroshi; Takeda, Hiroyuki; Yoshida, Koichi; Lorusso, Giuseppe; Watanabe, Hiroshi; Simpson, Gary S.; Jungclaus, Andrea; Baba, Hidetada; Browne, Frank; Doornenbal, Pieter; Gey, Guillaunme; Isobe, Tadaaki; Li, Zhihuan; Nishimura, Shunji; Söderström, Pär-Anders; Sumikama, Toshiyuki; Taprogge, Jan; Vajta, Zsolt; Wu, Jin; Xu, Zhengyu; Odahara, Atsuko; Yagi, Ayumi; Nishibata, Hiroki; Lozeva, Radomira; Moon, Changbum; Jung, HyoSoon

2018-01-01

The search for new isotopes using the in-flight fission of a 238U beam has been conducted concurrently with decay measurements, during the so-called EURICA campaigns, at the RIKEN Nishina Center RI Beam Factory. Fission fragments were analyzed and identified in flight using the BigRIPS separator. We have identified the following 36 new neutron-rich isotopes: 104Rb, 113Zr, 116Nb, 118,119Mo, 121,122Tc, 125Ru, 127,128Rh, 129,130,131Pd, 132Ag, 134Cd, 136,137In, 139,140Sn, 141,142Sb, 144,145Te, 146,147I, 149,150Xe, 149,150,151Cs, 153,154Ba, and 154,155,156,157La.

Certification of biological candidates reference materials by neutron activation analysis

NASA Astrophysics Data System (ADS)

Kabanov, Denis V.; Nesterova, Yulia V.; Merkulov, Viktor G.

2018-03-01

The paper gives the results of interlaboratory certification of new biological candidate reference materials by neutron activation analysis recommended by the Institute of Nuclear Chemistry and Technology (Warsaw, Poland). The correctness and accuracy of the applied method was statistically estimated for the determination of trace elements in candidate reference materials. The procedure of irradiation in the reactor thermal fuel assembly without formation of fast neutrons was carried out. It excluded formation of interfering isotopes leading to false results. The concentration of more than 20 elements (e.g., Ba, Br, Ca, Co, Ce, Cr, Cs, Eu, Fe, Hf, La, Lu, Rb, Sb, Sc, Ta, Th, Tb, Yb, U, Zn) in candidate references of tobacco leaves and bottom sediment compared to certified reference materials were determined. It was shown that the average error of the applied method did not exceed 10%.

Crystallographic site swapping of La3+ ion in BaA'LaTeO6 (A' = Na, K, Rb) double perovskite type compounds: diffraction and photoluminescence evidence for the site swapping.

PubMed

Phatak, R; Gupta, S K; Krishnan, K; Sali, S K; Godbole, S V; Das, A

2014-02-28

Double perovskite type compounds of the formula BaA'LaTeO6 (A' = Na, K, Rb) were synthesized by solid state route and their crystal structures were determined by Rietveld analysis using powder X-ray diffraction and neutron diffraction data. Na compound crystallizes in the monoclinic system with P2₁/n space group whereas, K and Rb compounds crystallize in Fm3m space group. All the three compounds show rock salt type ordering at B site. Crystal structure analysis shows that La ion occupies A site in Na compound whereas, it occupies B site in K and Rb compounds according to the general formula of AA'BB'O6 for a double perovskite type compound. Effect of this crystallographic site swapping of the La ion was also observed in the photoluminescence study by doping Eu(3+) in La(3+) site. The large decrease in the intensity of the electric dipole ((5)D0-(7)F2) transition in the Rb compound compared to the Na compound indicates that Eu(3+) ion resides in the centrosymmetric octahedral environment in the Rb compound.

Effect of the cation size on the framework structures of magnesium tungstate, A4Mg(WO4)3 (A = Na, K), R2Mg2(WO4)3 (R = Rb, Cs).

PubMed

Han, Shujuan; Wang, Ying; Jing, Qun; Wu, Hongping; Pan, Shilie; Yang, Zhihua

2015-03-28

A series of alkali metal magnesium tungstates, A4Mg(WO4)3 (A = Na, K), R2Mg2(WO4)3 (R = Rb, Cs), were synthesized from a high temperature solution, and their structures were determined by single-crystal X-ray diffraction. Interestingly, Na4Mg(WO4)3 crystallizes in the monoclinic space group C2/c, while K4Mg(WO4)3 having an identical stoichiometry with Na4Mg(WO4)3, exhibits a different framework structure belonging to triclinic symmetry with the space group P1[combining macron]. Isostructural Rb2Mg2(WO4)3 and Cs2Mg2(WO4)3 crystallize in the space group P213 of cubic symmetry and reveal a three dimensional framework composed of isolated WO4 tetrahedra, MgO6 octahedra and RO12 (R = Rb, Cs) polyhedra. The effect of the alkali metal cation size on the framework structures of magnesium tungstate has been discussed in detail. In addition, the infrared spectra, as well as the UV-Vis-NIR diffuse reflectance spectroscopy data, are reported. The first-principles theoretical studies are also carried out to aid the understanding of electronic structures and linear optical properties.

Adjusting the introduction of cations (MA, Cs or Rb) to obtain highly efficient and stable perovskite solar cells based on (FAPbI3)0.9(FAPbBr3)0.1.

PubMed

Liu, Guozhen; Zheng, Haiying; Zhu, Liangzheng; Alsaedi, Ahmed; Hayat, Tasawar; Pan, Xu; Mo, Li'e; Dai, Songyuan

2018-05-29

Although power conversion efficiency (PCE) of perovskite solar cells (PSCs) has increased to 22.7%, the instability when exposed to moisture and heat hindered their further practical development. In this study, to gain highly efficient and stable perovskite component, MA, Cs and Rb cations are respectively introduced into the (FAPbI3)0.9(FAPbBr3)0.1 film which is rarely used due to the poor photovoltaic performance. The effects of different contents of MA, Cs or Rb cations on the performance of (FAPbI3)0.9(FAPbBr3)0.1 films and devices are systematically studied. The results show that the devices with Cs cation exhibit markedly improved photovoltaic performance and stability, attributing to the obviously enhanced quality of films and their intrinsic stability. The (FAPbI3)0.9(FAPbBr3)0.1 devices with 10% Cs obtain a PCE as high as 19.94%. More importantly, the unsealed devices retain about 80% and 90% of the initial PCE at 85 °C after 260 h and under 45±5% relative humidity (RH) after 1440 h, respectively, which are more brilliant than that with 15% MA and 5% Rb under the same condition. It indicates that a highly efficient and stable perovskite component has been achieved and the PSCs based on this component will expect to promote the further development. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Linear-to-λ-Shape P-O-P Bond Transmutation in Polyphosphates with Infinite (PO3)∞ Chain.

PubMed

Wang, Ying; Li, Lin; Han, Shujuan; Lei, Bing-Hua; Abudoureheman, Maierhaba; Yang, Zhihua; Pan, Shilie

2017-09-05

A new metal polyphosphate, α-CsBa 2 (PO 3 ) 5 , exhibiting the first example of a linear P-O-P bond angle in a one-dimensional (PO 3 ) ∞ chain has been reported. Interestingly, α → β phase transition occurs in CsBa 2 (PO 3 ) 5 along with the P-O-P bonds varying from linear to λ-shape, suggesting that α-CsBa 2 (PO 3 ) 5 with unfavorable linear P-O-P bonds is more stable at ambient temperature.

Geochemistry and mineralogy of fly-ash from the Mae Moh lignite deposit, Thailand

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

Hart, B.R.; Powell, M.A.; Fyfe, W.S.

The concentration of 21 elements in fly ash from three boilers (75 MW, 150 MW, and 300 MW) at the EGAT power plant, Mae Moh, Thailand, were determined by INAA. The concentration of 10 major elements was determined by XRF. As, Co, Cr, Ni, Mo, and Sb generally increase in concentration going from bottom ash (BA) through the sequence of electrostatic precipitator ashes (ESPA) and reach maxima of As (352 ppm), Co (45 ppm), Cr (105 ppm), Mo (32 ppm), Ni (106 ppm), and Sb (15 ppm) in the ESPA. Ce, Cs, Fe, Hf, La, Sc, Ta, Tb, and Ybmore » did not exhibit concentration trends or are variable except in the case of one boiler, which showed an increase going from BA to ESPA. Only Br decreased in composition going from BA to ESPA. Rb, Sm, U, and Th showed marked variation in trends. The major elements identified by EDS were Al, Si, S, K, Ca, Fe, and Ba, with minor amounts of Mg, Na, Ti, Mn, and Sr. Al, Si, K, and Ca occur together and are present in most of the fly-ash particles. Ba was found as a major component with Ca, Al, and Si. Fe and Ca are usually associated with sulfur. Some small spheres (< 5 {mu}m) are comprised almost entirely of Fe (probably as oxide). Symplectite textures are noted in high-Fe phases. All elements except Br are significantly enriched in the fly ash relative to the coal, which contains 35% ash. Particle chemistry is consistent with the major mineral phases identified by XRD, which include: quartz, magnetite, mullite, gehlenite, anorthite, hematite, anhydrite, and clinopyroxene.« less

Characterizing suspended sediments from the Piracicaba River Basin by means of k0-INAA

NASA Astrophysics Data System (ADS)

França, E. J.; Fernandes, E. A. N.; Cavalca, I. P. O.; Fonseca, F. Y.; Camilli, L.; Rodrigues, V. S.; Bardini Junior, C.; Ferreira, J. R.; Bacchi, M. A.

2010-10-01

The inorganic chemical characterization of suspended sediments is of utmost relevance for the knowledge of the dynamics and movement of chemical elements in the aquatic and wet ecosystems. Despite the complexity of the effective design for studying this ecological compartment, this work has tested a procedure for analyzing suspended sediments by instrumental neutron activation analysis, k0 method ( k0-INAA). The chemical elements As, Ba, Br, Ca, Ce, Co, Cr, Cs, Eu, Fe, Hf, Hg, K, La, Mo, Na, Ni, Rb, Sb, Sc, Se, Sm, Sr, Ta, Tb, Th, Yb and Zn were quantified in the suspended sediment compartment by means of k0-INAA. When compared with World Average for rivers, high mass fractions of Fe (222,900 mg/kg), Ba (4990 mg/kg), Zn (1350 mg/kg), Cr (646 mg/kg), Co (74.5 mg/kg), Br (113 mg/kg) and Mo (31.9 mg/kg) were quantified in suspended sediments from the Piracicaba River, the Piracicamirim Stream and the Marins Stream. Results of the principal component analysis for standardized chemical element mass fractions indicated an intricate correlation among chemical elements evaluated, as a response of the contribution of natural and anthropogenic sources of chemical elements for ecosystems.

Planetary Astronomy

NASA Technical Reports Server (NTRS)

Stern, S. Alan

1998-01-01

This 1-year project was an augmentation grant to my NASA Planetary Astronomy grant. With the awarded funding, we accomplished the following tasks: (1) Conducted two NVK imaging runs in conjunction with the ILAW (International Lunar Atmosphere Week) Observing Campaigns in 1995 and 1997. In the first run, we obtained repeated imaging sequences of lunar Na D-line emission to better quantify the temporal variations detected in earlier runs. In the second run we obtained extremely high resolution (R=960.000) Na line profiles using the 4m AAT in Australia. These data are being analyzed under our new 3-year Planetary Astronomy grant. (2) Reduced, analyzed, and published our March 1995 spectroscopic dataset to detect (or set stringent upper limits on) Rb. Cs, Mg. Al. Fe, Ba, Ba. OH, and several other species. These results were reported in a talk at the LPSC and in two papers: (1) A Spectroscopic Survey of Metallic Abundances in the Lunar Atmosphere. and (2) A Search for Magnesium in the Lunar Atmosphere. Both reprints are attached. Wrote up an extensive, invited Reviews of Geophysics review article on advances in the study of the lunar atmosphere. This 70-page article, which is expected to appear in print in 1999, is also attached.

A theoretical study of the structure and thermochemical properties of alkali metal fluoroplumbates MPbF3.

PubMed

Boltalin, A I; Korenev, Yu M; Sipachev, V A

2007-07-19

Molecular constants of MPbF3 (M=Li, Na, K, Rb, and Cs) were calculated theoretically at the MP2(full) and B3LYP levels with the SDD (Pb, K, Rb, and Cs) and cc-aug-pVQZ (F, Li, and Na) basis sets to determine the thermochemical characteristics of the substances. Satisfactory agreement with experiment was obtained, including the unexpected nonmonotonic dependence of substance dissociation energies on the alkali metal atomic number. The bond lengths of the theoretical CsPbF3 model were substantially elongated compared with experimental estimates, likely because of errors in both theoretical calculations and electron diffraction data processing.

Radionuclide transfer to reptiles.

PubMed

Wood, Michael D; Beresford, Nicholas A; Semenov, Dmitry V; Yankovich, Tamara L; Copplestone, David

2010-11-01

Reptiles are an important, and often protected, component of many ecosystems but have rarely been fully considered within ecological risk assessments (ERA) due to a paucity of data on contaminant uptake and effects. This paper presents a meta-analysis of literature-derived environmental media (soil and water) to whole-body concentration ratios (CRs) for predicting the transfer of 35 elements (Am, As, B, Ba, Ca, Cd, Ce, Cm, Co, Cr, Cs, Cu, Fe, Hg, K, La, Mg, Mn, Mo, Na, Ni, Pb, Po, Pu, Ra, Rb, Sb, Se, Sr, Th, U, V, Y, Zn, Zr) to reptiles in freshwater ecosystems and 15 elements (Am, C, Cs, Cu, K, Mn, Ni, Pb, Po, Pu, Sr, Tc, Th, U, Zn) to reptiles in terrestrial ecosystems. These reptile CRs are compared with CRs for other vertebrate groups. Tissue distribution data are also presented along with data on the fractional mass of bone, kidney, liver and muscle in reptiles. Although the data were originally collected for use in radiation dose assessments, many of the CR data presented in this paper will also be useful for chemical ERA and for the assessments of dietary transfer in humans for whom reptiles constitute an important component of the diet, such as in Australian aboriginal communities.

Electron Impact Ionization Cross Sections in Rb and Cs.

NASA Astrophysics Data System (ADS)

Reddish, T. J.; Lukomski, M.; Sutton, S.; Kedzierski, W.; McConkey, J. W.; Bartschat, K.; Bartlett, P. L.; Stelbovics, A. T.; Bray, I.

2006-05-01

We present a new atom trapping technique for determining absolute, total ionisation cross sections (TICS) out of an excited atom. The novel feature of this method is in utilizing Doppler cooling of neutral atoms to determine ionisation cross sections. This fluorescence-monitoring experiment, which is a variant of the `trap loss' technique, has enabled us to obtain the experimental electron impact ionisation cross sections out of the Cs 6^2P3/2 excited state between 7 - 400 eV. New CCC, R-Matrix with Pseudo-States (RMPS), and Born approximation single ionisation cross sections (SICS) are also presented for both the ground and excited states of Cs and Rb, and compared with the available experimental data. The comparison of the results reveals the importance of the autoionisation and multiple ionisation contributions to the TICS. The autoionisation contribution appears to be substantial for ionisation out of the Cs 6^2P and Rb 5^2P excited states; ˜ 3-4 larger than the direct ionisation contribution predicted by CCC at ˜ 30-50 eV. This surprising result shows the importance of multi-electron processes in determining the ionisation cross sections of heavy alkali atoms.

Hydrothermal crystal growth of ABe 2BO 3F 2 (A=K, Rb, Cs, Tl) NLO crystals

NASA Astrophysics Data System (ADS)

McMillen, Colin D.; Kolis, Joseph W.

2008-04-01

Crystals of a family of compounds, ABe 2BO 3F 2 (ABBF, A=K, Rb, Cs, Tl), have been grown hydrothermally. Each of these materials was studied using the powder SHG technique and exhibited promising NLO behavior. Seeded crystal growth was demonstrated and the growth conditions were optimized by modifying the temperature, thermal gradient and mineralizer concentration. RbBe 2BO 3F 2 crystals possessed a particularly good combination of SHG intensity, favorable crystal habit and fast growth rates. High quality crystals suitable for advanced deep-UV NLO studies were grown at rates of 0.11 mm/day on (0 0 1) and 0.12 mm/day perpendicular to (0 0 1).

Phosphate glass useful in high energy lasers

DOEpatents

Hayden, Y.T.; Guesto-Barnak, D.

1992-12-22

Disclosed is a low-or no-silica, low- or no-alkali phosphate glass useful as a laser amplifier in a multiple pass, high energy laser system having a high thermal conductivity, K[sub 90 C] >0.85 W/mK, a low coefficient of thermal expansion, [alpha][sub 20-300 C] <80[times]10[sup [minus]7]/C, low emission cross section, [sigma]<2.5[times]10[sup [minus]20] cm[sup 2], and a high fluorescence lifetime, [tau]>325 [mu]secs at 3 wt. % Nd doping, consisting essentially of (on an oxide composition basis): (Mole %) P[sub 2]O[sub 5], (52-72); Al[sub 2]O[sub 3], (0-<20); B[sub 2]O[sub 3], (>0-25); ZnO, (0-31); Li[sub 2]O, (0-5); K[sub 2]O, (0-5); Na[sub 2]O, (0-5); Cs[sub 2]O, (0-5); Rb[sub 2]O, (0-5); MgO, (>0-<30); CaO, (0-20); BaO, (0-20); SrO, (0-<20); Sb[sub 2]O[sub 3], (0-<1); As[sub 2]O[sub 3], (0-<1); Nb[sub 2]O[sub 5], (0-<1); Ln[sub 2]O[sub 3], (up to 6.5); PbO, (0-<5); and SiO[sub 2], (0-3); wherein Ln[sub 2]O[sub 3] is the sum of lanthanide oxides; [Sigma]R[sub 2]O is <5, R being Li, Na, K, Cs, and Rb; the sum of Al[sub 2]O[sub 3] and MgO is <24 unless [Sigma]R[sub 2]O is 0, then the sum of Al[sub 2]O[sub 3] and MgO is <42; and the ratio of MgO to B[sub 2]O[sub 3] is 0.48-4.20. 7 figs.

Mechano-electrical transduction currents in isolated vestibular hair cells of the chick.

PubMed

Ohmori, H

1985-02-01

Properties of a mechano-electrical transduction channel were studied in enzymatically dissociated chick vestibular hair cells by using a whole-cell recording variation of the patch voltage-clamp technique. The apical hair bundle was stimulated by a glass rod which moved along a one-dimensional axis when stimulated by either a triangular or a trapezoidal command voltage. The motion of the glass rod was monitored optically using a photodiode. In response to triangular stimuli, the hair cell generated a current of triangular wave form with occasional step-like spiky or zigzag-appearing events. Control experiments confirmed that the current was generated only when the hair bundle was displaced towards the tallest stereocilium. The mechano-sensitive current was blocked by streptomycin and by neomycin. The blockage by streptomycin was clearly voltage dependent: the reduction of the current became larger with hyperpolarization of the membrane. This suggests that the positively charged antibiotic molecules plug the mechanically gated channels. From the evidence presented in 3 and 4 above, the mechano-sensitive current recorded here was identified as the mechano-electrical transduction (m-e.t.) current. The permeability of the m-e.t. channel to various monovalent cations was determined from reversal potential measurements. Since a CsCl-EGTA intracellular medium was used, all the permeabilities were calculated relative to PCs. The sequence of permeabilities was Li greater than Na greater than or equal to K greater than or equal to Rb greater than Cs greater than choline greater than TMA greater than TEA. External Ca ions were indispensable for the recording of transduction current and Sr ions could replace Ca ions without loss of the transduction activity. The minimum [Ca]o for stable generation of the m-e.t. current was 20 microM in Cs saline. The addition of 50-200 microM-Ca to the isotonic Ba saline could maintain the m-e.t. current. The m-e.t. current was observed in isotonic Ca and in Sr salines. Isotonic Ba, Mg and Mn salines were enriched with 1-2 mM-Ca in order to generate the m-e.t. current. The permeabilities of the divalent cations relative to Cs were calculated from the reversal potentials, and the sequence of permeabilities among divalent cations was Ca greater than Sr greater than Ba greater than Mn greater than Mg. Step-like m-e.t. currents were observed in Cs saline. The smallest step amplitude with clear resolution had a conductance of 49.7 +/- 4.5 pS (mean +/- S.D., n = 7 cells). This is likely to be an elementary m-e.t. channel conductance.(ABSTRACT TRUNCATED AT 400 WORDS)

Syntheses and characterization of one-dimensional alkali metal antimony(III) thiostannates(IV), A{sub 2}Sb{sub 2}Sn{sub 3}S{sub 10} (A=K, Rb, Cs)

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

Yohannan, Jinu P.; Vidyasagar, Kanamaluru, E-mail: kvsagar@iitm.ac.in

2015-01-15

Three new isostructural quaternary antimony(III) thiostannates(IV), A{sub 2}Sb{sub 2}Sn{sub 3}S{sub 10} (A=K, Rb, Cs) have been synthesized by using alkali metal thiosulfate flux and structurally characterized by X-ray diffraction. Their structures contain A{sup +} ions around the [Sb{sub 2}Sn{sub 3}S{sub 10}]{sup 2−} chains, which are built from SbS{sub 3} pyramids, SnS{sub 6} octahedra and SnS{sub 4} tetrahedra. Raman and Mössbauer spectroscopic measurements corroborate the oxidation states and coordination environments of Sb(III) and Sn(IV). All three compounds are wide band gap semiconductors. Potassium compound undergoes partial exchange with strontium, cadmium and lead ions. - Graphical abstract: Syntheses, crystal structure, spectroscopic andmore » partial ion-exchange studies of new one-dimensional alkali metal antimony(III) thiostannates(IV), A{sub 2}Sb{sub 2}Sn{sub 3}S{sub 10} (A=K, Rb, Cs) are described. - Highlights: • Syntheses of new alkali metal antimony(III) thiostannates(IV), A{sub 2}Sb{sub 2}Sn{sub 3}S{sub 10} (A=K, Rb, Cs). • Wide band gap semiconductors with one-dimensional structure. • Topotactic partial exchange of K{sup +} ions of K{sub 2}Sb{sub 2}Sn{sub 3}S{sub 10} with Sr{sup 2+}, Cd{sup 2+} and Pb{sup 2+} ions.« less

Variable dimensionality and framework found in a series of quaternary zinc selenites, A{sub 2}Zn{sub 3}(SeO{sub 3}){sub 4}·xH{sub 2}O (A = Na, Rb, and Cs; 0≤x≤1) and Cs{sub 2}Zn{sub 2}(SeO{sub 3}){sub 3}·2H{sub 2}O

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

Lü, Minfeng; Jo, Hongil; Oh, Seung-Jin

Five new alkali metal zinc selenites, A{sub 2}Zn{sub 3}(SeO{sub 3}){sub 4}·xH{sub 2}O (A = Na, Rb, and Cs; 0≤x≤1) and Cs{sub 2}Zn{sub 2}(SeO{sub 3}){sub 3}·2H{sub 2}O have been synthesized by heating a mixture of ZnO, SeO{sub 2} and A{sub 2}CO{sub 3} (A = Na, Rb, and Cs), and characterized by X-ray diffraction (XRD) and spectroscopic analyses techniques. All of the reported materials revealed a rich structural chemistry with different frameworks and connection modes of Zn{sup 2+}. While Rb{sub 2}Zn{sub 3}(SeO{sub 3}){sub 4} and Cs{sub 2}Zn{sub 3}(SeO{sub 3}){sub 4}·H{sub 2}O revealed three-dimensional frameworks consisting of isolated ZnO{sub 4} tetrahedra and SeO{submore » 3} polyhedra, Na{sub 2}Zn{sub 3}(SeO{sub 3}){sub 4}, Cs{sub 2}Zn{sub 3}(SeO{sub 3}){sub 4}, and Cs{sub 2}Zn{sub 2}(SeO{sub 3}){sub 3}·2H{sub 2}O contained two-dimensional [Zn{sub 3}(SeO{sub 3}){sub 4}]{sup 2-} layers. Specifically, whereas isolated ZnO{sub 4} tetrahedra and SeO{sub 3} polyhedra are arranged into two-dimensional [Zn{sub 3}(SeO{sub 3}){sub 4}]{sup 2-} layers in two cesium compounds, circular [Zn{sub 3}O{sub 10}]{sup 14-} chains and SeO{sub 3} linkers are formed in two-dimensional [Zn{sub 3}(SeO{sub 3}){sub 4}]{sup 2-} layers in Na{sub 2}Zn{sub 3}(SeO{sub 3}){sub 4}. Close structural examinations suggest that the size of alkali metal is significant in determining the framework geometry as well as connection modes of transition metal cations. - Graphical abstract: Variable dimensions and frameworks were found in a series of quaternary zinc selenites, A{sub 2}Zn{sub 3}(SeO{sub 3}){sub 4} (A = Na, Rb and Cs). - Highlights: • Five novel quaternary zinc selenites are synthesized. • All the selenites with different structures contain polarizable d{sup 10} and lone pair cations. • The size of alkali metal cations is significant in determining the framework geometry.« less

Ternary alkali-metal and transition metal or metalloid acetylides as alkali-metal intercalation electrodes for batteries

DOEpatents

Nemeth, Karoly; Srajer, George; Harkay, Katherine C; Terdik, Joseph Z

2015-02-10

Novel intercalation electrode materials including ternary acetylides of chemical formula: A.sub.nMC.sub.2 where A is alkali or alkaline-earth element; M is transition metal or metalloid element; C.sub.2 is reference to the acetylide ion; n is an integer that is 0, 1, 2, 3 or 4 when A is alkali element and 0, 1, or 2 when A is alkaline-earth element. The alkali elements are Lithium (Li), Sodium (Na), Potassium (K), Rubidium (Rb), Cesium (Cs) and Francium (Fr). The alkaline-earth elements are Berilium (Be), Magnesium (Mg), Calcium (Ca), Strontium (Sr), Barium (Ba), and Radium (Ra). M is a transition metal that is any element in groups 3 through 12 inclusive on the Periodic Table of Elements (elements 21 (Sc) to element 30 (Zn)). In another exemplary embodiment, M is a metalloid element.

Air Pollution Study in the Republic of Moldova Using Moss Biomonitoring Technique.

PubMed

Zinicovscaia, Inga; Hramco, Constantin; Duliu, Octavian G; Vergel, Konstantin; Culicov, Otilia A; Frontasyeva, Marina V; Duca, Gheorghe

2017-02-01

Moss biomonitoring using the species Hypnum cupressiforme (Hedw.) and Pleurocarpous sp was applied to study air pollution in the Republic of Moldova. A total of 41 elements (Na, Mg, Al, Cl, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Br, Rb, Sr, Zr, Cd, Sb, Cs, Ba, La, Ce, Nd, Sm, Eu, Gd, Tb, Tm, Yb, Hf, Ta, W, Pb, Th, and U) were determined by instrumental epithermal neutron activation analysis and atomic absorption spectrometry. Principal component analysis was used to identify and characterize different pollution sources. Geographical distribution maps were prepared to point out the regions most affected by air pollution and relate this to potential sources of contamination. Median values of the elements studied were compared with data from the European moss biomonitoring program. The cities of Chisinau and Balti were determined to experience particular environmental stress.

Spin Polarization of Rb and Cs n p P2 3/2 (n =5 , 6) Atoms by Circularly Polarized Photoexcitation of a Transient Diatomic Molecule

NASA Astrophysics Data System (ADS)

Mironov, A. E.; Hewitt, J. D.; Eden, J. G.

2017-03-01

We report the selective population of Rb or Cs n p P2 3/2 (n =5 , 6; F =4 , 5) hyperfine states by the photodissociation of a transient, alkali-rare gas diatomic molecule. Circularly polarized (σ-), amplified spontaneous emission (ASE) on the D2 line of Rb or Cs (780.0 and 852.1 nm, respectively) is generated when Rb-Xe or Cs-Xe ground state collision pairs are photoexcited by a σ+-polarized optical field having a wavelength within the D2 blue satellite continuum, associated with the B Σ2 1/2 +←X Σ2 1/2 + (free←free ) transition of the diatomic molecule. The degree of spin polarization of Cs (6 p P3/2 2 ), specifically, is found to be dependent on the interatomic distance (R ) at which the excited complex is born, a result attributed to the structure of the B Σ2 1/2 + state. For Cs-Xe atomic pairs, tuning the wavelength of the optical field from 843 to 848 nm varies the degree of circular polarization of the ASE from 63% to almost unity because of the perturbation, in the 5 ≤R ≤6 Å interval, of the Σ2 1/2 + potential by a d σ molecular orbital associated with a higher Λ 2 electronic state. Monitoring only the Cs 6 p P3/2 2 spin polarization reveals a previously unobserved interaction of CsXe (B Σ2 1/2 + ) with the lowest vibrational levels of a Λ 2 state derived from Cs (5 d )+Xe . By inserting a molecular intermediate into the alkali atom excitation mechanism, these experiments realize electronic spin polarization through populating no more than two n p P2 3/2 hyperfine states, and demonstrate a sensitive spectroscopic probe of R -dependent state-state interactions and their impact on interatomic potentials.

Highly efficient red-emitting BaMgBO3F:Eu3+,R+ (R: Li, Na, K, Rb) phosphor for near-UV excitation synthesized via glass precursor solid-state reaction

NASA Astrophysics Data System (ADS)

Shinozaki, Kenji; Akai, Tomoko

2017-09-01

Eu3+-doped fluoroborate crystals of BaMgBO3F were synthesized by a solid-state reaction using a glassy precursor material, and their photoluminescence (PL) was investigated. To compensate for the incorporation of Eu3+ into Ba2+ sites, samples codoped with alkali ions (Li+, Na+, K+, Rb+) were also prepared. The Eu3+-doped sample showed red PL with a quantum yield (QY) of 65% caused by near-UV excitation (λ = 393 nm), and PL intensity and QY increased with the codoping of Eu3+ and alkali ions. It was found that the Eu3+,Li+-codoped sample showed the highest PL intensity and a QY of 83%.

Cs-135 - Ba-135: A new cosmochronometric constraint on the origin of the Earth and the astrophysical site of the origin of the solar system

NASA Technical Reports Server (NTRS)

Harper, C. L.; Wiesmann, H.; Nyquist, L. E.

1991-01-01

It is argued that if Cs-135 was indeed present in the early solar system at the level inferred from evidence presented here, then two major conclusions follow. (1) A supernova contributed newly synthesized r-process matter into the protosolar reservoir within approx. 5 Ma of the Cs/Ba fractionation recorded in LEW 86010; (2) The strong Cs depletion in the bulk Earth reservoir (Cs-133/Ba-135 approx. 0.1) took place very early in solar system history. If this volatile loss was pre-accretionary, then the accretionary chronology of the Earth is not constrained. However, if it is a consequence of accretion, then the very tight time constraint of approx. less than 5 Ma (rel. to LEW 86010) is obtained for accretion of most of the Earth's mass.

Cs-135 - Ba-135: A new cosmochronometric constraint on the origin of the Earth and the astrophysical site of the origin of the solar system

NASA Astrophysics Data System (ADS)

Harper, C. L.; Wiesmann, H.; Nyquist, L. E.

It is argued that if Cs-135 was indeed present in the early solar system at the level inferred from evidence presented here, then two major conclusions follow. (1) A supernova contributed newly synthesized r-process matter into the protosolar reservoir within approx. 5 Ma of the Cs/Ba fractionation recorded in LEW 86010; (2) The strong Cs depletion in the bulk Earth reservoir (Cs-133/Ba-135 approx. 0.1) took place very early in solar system history. If this volatile loss was pre-accretionary, then the accretionary chronology of the Earth is not constrained. However, if it is a consequence of accretion, then the very tight time constraint of approx. less than 5 Ma (rel. to LEW 86010) is obtained for accretion of most of the Earth's mass.

Energy Scaling of Cold Atom-Atom-Ion Three-Body Recombination

NASA Astrophysics Data System (ADS)

Krükow, Artjom; Mohammadi, Amir; Härter, Arne; Denschlag, Johannes Hecker; Pérez-Ríos, Jesús; Greene, Chris H.

2016-05-01

We study three-body recombination of Ba++Rb +Rb in the mK regime where a single 138Ba+ ion in a Paul trap is immersed into a cloud of ultracold 87Rb atoms. We measure the energy dependence of the three-body rate coefficient k3 and compare the results to the theoretical prediction, k3∝Ecol-3 /4, where Ecol is the collision energy. We find agreement if we assume that the nonthermal ion energy distribution is determined by at least two different micromotion induced energy scales. Furthermore, using classical trajectory calculations we predict how the median binding energy of the formed molecules scales with the collision energy. Our studies give new insights into the kinetics of an ion immersed in an ultracold atom cloud and yield important prospects for atom-ion experiments targeting the s -wave regime.

Detection of uranium and chemical state analysis of individual radioactive microparticles emitted from the Fukushima nuclear accident using multiple synchrotron radiation X-ray analyses.

PubMed

Abe, Yoshinari; Iizawa, Yushin; Terada, Yasuko; Adachi, Kouji; Igarashi, Yasuhito; Nakai, Izumi

2014-09-02

Synchrotron radiation (SR) X-ray microbeam analyses revealed the detailed chemical nature of radioactive aerosol microparticles emitted during the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident, resulting in better understanding of what occurred in the plant during the early stages of the accident. Three spherical microparticles (∼2 μm, diameter) containing radioactive Cs were found in aerosol samples collected on March 14th and 15th, 2011, in Tsukuba, 172 km southwest of the FDNPP. SR-μ-X-ray fluorescence analysis detected the following 10 heavy elements in all three particles: Fe, Zn, Rb, Zr, Mo, Sn, Sb, Te, Cs, and Ba. In addition, U was found for the first time in two of the particles, further confirmed by U L-edge X-ray absorption near-edge structure (XANES) spectra, implying that U fuel and its fission products were contained in these particles along with radioactive Cs. These results strongly suggest that the FDNPP was damaged sufficiently to emit U fuel and fission products outside the containment vessel as aerosol particles. SR-μ-XANES spectra of Fe, Zn, Mo, and Sn K-edges for the individual particles revealed that they were present at high oxidation states, i.e., Fe(3+), Zn(2+), Mo(6+), and Sn(4+) in the glass matrix, confirmed by SR-μ-X-ray diffraction analysis. These radioactive materials in a glassy state may remain in the environment longer than those emitted as water-soluble radioactive Cs aerosol particles.

The Barium Site in a Potassium Channel by X-Ray Crystallography

PubMed Central

Jiang, Youxing; MacKinnon, Roderick

2000-01-01

X-ray diffraction data were collected from frozen crystals (100°K) of the KcsA K+ channel equilibrated with solutions containing barium chloride. Difference electron density maps (Fbarium − Fnative, 5.0 Å resolution) show that Ba2+ resides at a single location within the selectivity filter. The Ba2+ blocking site corresponds to the internal aspect (adjacent to the central cavity) of the “inner ion” position where an alkali metal cation is found in the absence of the blocking Ba2+ ion. The location of Ba2+ with respect to Rb+ ions in the pore is in good agreement with the findings on the functional interaction of Ba2+ with K+ (and Rb+) in Ca2+-activated K+ channels (Neyton, J., and C. Miller. 1988. J. Gen. Physiol. 92:549–567). Taken together, these structural and functional data imply that at physiological ion concentrations a third ion may interact with two ions in the selectivity filter, perhaps by entering from one side and displacing an ion on the opposite side. PMID:10694255

Resonance lines and energy levels of Cs III, Ba IV, and La V

NASA Technical Reports Server (NTRS)

Epstein, G. L.; Reader, J.

1976-01-01

Spectra of Cs III, Ba IV, and La V were photographed in a low-voltage sliding spark on a 10.7 m normal-incidence vacuum spectrograph. These ions are isoelectronic with neutral iodine and display a halogen-like energy level structure. Detailed isoelectronic comparisons, level transition diagrams, and tabular data on the transitions of the ions and percentage compositions of Cs III configurations are presented.

Geochronology and petrogenesis of the Early Cretaceous A-type granite from the Feie'shan W-Sn deposit in the eastern Guangdong Province, SE China: Implications for W-Sn mineralization and geodynamic setting

NASA Astrophysics Data System (ADS)

Liu, Peng; Mao, Jingwen; Santosh, M.; Bao, Zhian; Zeng, Xiaojian; Jia, Lihui

2018-02-01

The Feie'shan greisen-type W-Sn deposit in the eastern Guangdong Province forms part of the Southeastern Coastal Metallogenic Belt (SCMB) in South China. Here we present zircon LA-ICP-MS U-Pb geochronology of the biotite granite which shows a weighted mean 206Pb/238U age of 134.7 ± 2.0 Ma, consistent with the zircon U-Pb, biotite 40Ar-39Ar and molybdenite Re-Os ages in the previous study. The biotite granite is peraluminous and belongs to high-K calc-alkaline type. It is characterized by high SiO2, K2O, F, K2O + Na2O and FeOt/(FeOt + MgO), and low CaO, MgO, TiO2 and P2O5 contents, enrichment in Rb, Cs, Th and U, and depletion in Ba, Sr, Zr, Ti and P, with flat REE patterns and distinctly negative Eu anomalies, showing an A2-type affinity. The rocks also display extremely low Ba, Sr and Ti concentrations and high Rb/Sr, Rb/Ba and low CaO/(Na2O + K2O) ratios, indicating high degree of fractionation. Zircon grains from the granite have low Eu/Eu* and Ce4 +/Ce3 + ratios, suggesting low oxygen fugacity. The highly fractionated and reduced features imply that the Feie'shan mineralization is genetically related to the biotite granite. The εNd(t) values and zircon εHf(t) values of the biotite granite range from - 2.96 to - 1.95 and - 5.69 to 0.62, with two-stage Nd and Hf model ages (TDM2) of 1083 to 1164 Ma and 1150 to 1552 Ma, indicating that they were derived from magma hybridization between anatectic granitic and mantle-derived mafic magmas. In combination with previous studies, we propose a geodynamic model for the 145―135 Ma W-Sn mineral system and related magmatism in the southwestern domain of the SCMB. After ca. 145 Ma, the subduction orientation of the Izanagi plate changed from oblique to parallel with respect to the continental margin resulting in large-scale lithosphere extension and thinning, which led to the upwelling of asthenosphere. The ascending mantle-derived mafic magmas provided not only supplied the heat for crustal remelting but also added juvenile mantle-derived melts resulting in the formation of mafic dikes, and I- or A-type granitic intrusions related to the W-Sn ore mineral systems.

Phase Transition, Conformational Exchange, and Nonlinear Optical Third Harmonic Generation of A CsP 2 Se 8 ( A = K, Rb, Cs)

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

Haynes, Alyssa S.; Banerjee, Abhishek; Saouma, Felix O.

2016-04-12

The soluble molecular selenophosphate salts ACsP(2)Se(8) (A = K, Rb, Cs) crystallize in the orthorhombic space group Ccce with a = 14.982(3) A, b = 24.579(5) A, and c = 13.065(3) A for the Cs salt and a = 14.782(3) A, b = 23.954(5) A, and c = 13.044(3) A for the K analogue. ACsP2Se8 is composed of the molecular 6-membered ring, [P2Se8](2-), in the twist conformation charge balanced by alkali metals. The band gaps of these compounds are 2.44 +/- 0.2 eV for Cs2P2Se8, 2.41 +/- 0.2 eV for RbCsP2Se8, and 2.36 +/- 0.2 eV for KCsP2Se8. The amorphousmore » versions of these materials can be made by water quenching the melt and have band gaps for all ACsP(2)Se(8) of 2.12 +/- 0.2 eV. Raman spectroscopic studies exhibit active modes of PSe4 and Se Se in the compound. Solution P-31 NMR studies shed light into the interesting conformational fluxionality of the [P2Se8](2-) anion, including a conformation that has not been previously observed. Thermal analysis reveals ACsP(2)Se(8) exhibits a phase transition, which we investigate by in situ synchrotron powder X-ray diffraction. Third harmonic generation (THG) nonlinear optical measurements determined the THG coefficient, chi(3), for amorphous and crystalline Cs2P2Se8 of 1.8 +/- 0.2 X 105 pm(2)/V-2 and 2.4 +/- 0.1 X 105 pm2/V2, respectively.« less

Petrogenesis of the mafic microgranular enclaves (MMEs) and their host granodiorites from the Zijinshan intrusion along the Middle-Lower Yangtze River Valley: Implications for geodynamic setting and mineralization

NASA Astrophysics Data System (ADS)

Liu, Peng; Mao, Jingwen; Yao, Wei; Wang, Xiaoxia; Jia, Lihui; Yang, Hanwen

2017-09-01

The Zijinshan intrusion is located to the south of the Tongling ore cluster of the Middle-Lower Yangtze River Valley metallogenic belt (YRB) and even south to the Yangxing-Changzhou Fault (YCF), which separates the YRB and the Jiangnan Massif. It is an I-type high-K calc-alkaline granodiorite with abundant MMEs. Zircon LA-MC-ICP-MS U-Pb ages of 144.0 ± 1.0 Ma and 142.5 ± 1.0 Ma for the host granodiorite and MMEs indicate coeval formation. Biotites from the host granodiorites and MMEs have similar composition, with low FeOt/(FeOt + MgO) values of 0.60-0.65 and 0.60-0.65, and high MgO contents of 10.51-11.70 wt.% and 10.89-12.37 wt.%, respectively. All the biotite samples are between the NNO and the MH buffers. The host granodiorites are metaluminous (A/CNK = 0.94-0.95), enriched in Cs, Rb, U and Pb, depleted in Ba, Sr, Nb, Zr, P, and Ti, with moderate negative Eu anomalies of 0.80-0.87, (87Sr/86Sr)i of 0.70874 to 0.70887, εNd(t) of - 5.63 to - 5.36 and εHf(t) of - 8.68 to - 2.76. The MMEs have lower SiO2 and higher K2O, and they are also enriched in Cs, Rb, U, Ta and Pb, and depleted in Ba, Sr, Nb, Zr, P and Ti, with (87Sr/86Sr)i of 0.70889 to 0.70927, εNd(t) of - 5.52 to - 5.20 and εHf(t) of - 6.46 to - 3.59. All these characteristics demonstrate that partial melting of both the lower crust and an enriched lithospheric mantle metasomatized by subducted slab fluid and their subsequent mixing led to the origin of the I-type granodiorite magmas of the Zijinshan intrusion, which took place in the geodynamic context of the subduction of the Izanagi plate. Combined with the field investigations, we suggest that the Zijinshan intrusion has potential for porphyry Cu-Au mineralization and the Cu-Au metallogenic belt of the YRB may have extended to the south of the YCF.

Chemistry of Tertiary sediments in the surroundings of the Ries impact structure and moldavite formation revisited

NASA Astrophysics Data System (ADS)

Žák, Karel; Skála, Roman; Řanda, Zdeněk; Mizera, Jiří; Heissig, Kurt; Ackerman, Lukáš; Ďurišová, Jana; Jonášová, Šárka; Kameník, Jan; Magna, Tomáš

2016-04-01

Moldavites, tektites of the Central European strewn field, have been traditionally linked with the Ries impact structure in Germany. They are supposed to be derived mainly from the near-surface sediments of the Upper Freshwater Molasse of Miocene age that probably covered the target area before the impact. Comparison of the chemical composition of moldavites with that of inferred source materials requires recalculation of the composition of sediments to their water-, organic carbon- and carbon dioxide-free residuum. This recalculation reflects the fact that these compounds were lost almost completely from the target materials during their transformation to moldavites. Strong depletions in concentrations of many elements in moldavites relative to the source sediments (e.g., Mo, Cu, Ag, Sb, As, Fe) contrast with enrichments of several elements in moldavites (e.g., Cs, Ba, K, Rb). These discrepancies can be generally solved using two different approaches, either by involvement of a component of specific chemical composition, or by considering elemental fractionation during tektite formation. The proposed conceptual model of moldavite formation combines both approaches and is based on several steps: (i) the parent mixture (Upper Freshwater Molasse sediments as the dominant source) contained also a minor admixture of organic matter and soils; (ii) the most energetic part of the ejected matter was converted to vapor (plasma) and another part produced melt directly upon decompression; (iii) following further adiabatic decompression, the expanding vapor phase disintegrated the melt into small melt droplets and some elements were partially lost from the melt because of their volatility, or because of the volatility of their compounds, such as carbonyls of Fe and other transition metals (e.g., Ni, Co, Mo, Cr, and Cu); (iv) large positively charged ions such as Cs+, Ba2+, K+, Rb+ from the plasma portion were enriched in the late-stage condensation spherules or condensed directly onto negatively charged melt droplets; (v) simultaneously, the melt droplets coalesced into larger tektite bodies. Steps (iii)-(v) may have overlapped in time. The still melted moldavite bodies reaching their final size were reshaped by further melt flow. This melt flow was related to moldavite rotation and escape (bubbling off) of the last portion of gaseous volatiles during their flight in a low-pressure region above the dense layer of the atmosphere.

Cesium iodide alloys

DOEpatents

Kim, H.E.; Moorhead, A.J.

1992-12-15

A transparent, strong CsI alloy is described having additions of monovalent iodides. Although the preferred iodide is AgI, RbI and CuI additions also contribute to an improved polycrystalline CsI alloy with outstanding multispectral infrared transmittance properties. 6 figs.

The determination of potential energy curve and dipole moment of the (5)0{sup +} electronic state of {sup 85}Rb{sup 133}Cs molecule by high resolution photoassociation spectroscopy

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

Yuan, Jinpeng; Zhao, Yanting, E-mail: zhaoyt@sxu.edu.cn; Ji, Zhonghua

2015-12-14

We present the formation of ultracold {sup 85}Rb{sup 133}Cs molecules in the (5)0{sup +} electronic state by photoassociation and their detection via resonance-enhanced two-photon ionization. Up to v = 47 vibrational levels including the lowest v = 0 vibrational and lowest J = 0 levels are identified with rotationally resolved high resolution photoassociation spectra. Precise Dunham coefficients are determined for the (5)0{sup +} state with high accuracy, then the Rydberg-Klein-Rees potential energy curve is derived. The electric dipole moments with respect to the vibrational numbers of the (5)0{sup +} electronic state of {sup 85}Rb{sup 133}Cs molecule are also measured inmore » the range between 1.9 and 4.8 D. These comprehensive studies on previously unobserved rovibrational levels of the (5)0{sup +} state are helpful to understand the molecular structure and discover suitable transition pathways for transferring ultracold atoms to deeply bound rovibrational levels of the electronic ground state.« less

Increasing stripe-type fluctuations in A Fe2As2 (A =K , Rb, Cs) superconductors probed by 75As NMR spectroscopy

NASA Astrophysics Data System (ADS)

Zhang, Z. T.; Dmytriieva, D.; Molatta, S.; Wosnitza, J.; Khim, S.; Gass, S.; Wolter, A. U. B.; Wurmehl, S.; Grafe, H.-J.; Kühne, H.

2018-03-01

We report 75As nuclear magnetic resonance measurements on single crystals of RbFe2As2 and CsFe2As2 . Taking previously reported results for KFe2As2 into account, we find that the anisotropic electronic correlations evolve towards a magnetic instability in the A Fe2As2 series (with A =K , Rb, Cs). Upon isovalent substitution with larger alkali-metal ions, a drastic enhancement of the anisotropic nuclear spin-lattice relaxation rate and decreasing Knight shift reveal the formation of pronounced spin fluctuations with stripe-type modulation. Furthermore, a decreasing power-law exponent of the nuclear spin-lattice relaxation rate (1/T1)H ∥a b, probing the in-plane spin fluctuations, evidences an emergent deviation from Fermi-liquid behavior. All these findings clearly indicate that the expansion of the lattice in the A Fe2As2 series tunes the electronic correlations towards a quantum critical point at the transition to a yet unobserved ordered phase.

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

Joseph, Kitheri; Stennett, Martin C.; Hyatt, Neil C.

Bulk properties such as glass transition temperature, density and thermal expansion of iron phosphate glass compositions, with replacement of Cs by Ba, are investigated as a surrogate for the transmutation of 137Cs to 137Ba, relevant to the immobilisation of Cs in glass. These studies are required to establish the appropriate incorporation rate of 137Cs in iron phosphate glass. Density and glass transition temperature increases with the addition of BaO indicating the shrinkage and reticulation of the iron phosphate glass network. The average thermal expansion coefficient reduces from 19.8 × 10-6 K-1 to 13.4 × 10-6 K-1, when 25 wt. %more » of Cs2O was replaced by 25 wt. % of BaO in caesium loaded iron phosphate glass. In addition to the above bulk properties, the role of Ba as a network modifier in the structure of iron phosphate glass is examined using various spectroscopic techniques. The FeII content and average coordination number of iron in the glass network was estimated using Mössbauer spectroscopy. The FeII content in the un-doped iron phosphate glass and barium doped iron phosphate glasses was 20, 21 and 22 ± 1% respectively and the average Fe coordination varied from 5.3 ± 0.2 to 5.7 ± 0.2 with increasing Ba content. The atomic scale structure was further probed by Fe K-edge X-ray absorption spectroscopy. The average coordination number provided by extended X-ray absorption fine structure spectroscopy and X-ray absorption near edge structure was in good agreement with that given by the Mössbauer data.« less

Iron phosphate glasses: Bulk properties and atomic scale structure

NASA Astrophysics Data System (ADS)

Joseph, Kitheri; Stennett, Martin C.; Hyatt, Neil C.; Asuvathraman, R.; Dube, Charu L.; Gandy, Amy S.; Govindan Kutty, K. V.; Jolley, Kenny; Vasudeva Rao, P. R.; Smith, Roger

2017-10-01

Bulk properties such as glass transition temperature, density and thermal expansion of iron phosphate glass compositions, with replacement of Cs by Ba, are investigated as a surrogate for the transmutation of 137Cs to 137Ba, relevant to the immobilisation of Cs in glass. These studies are required to establish the appropriate incorporation rate of 137Cs in iron phosphate glass. Density and glass transition temperature increases with the addition of BaO indicating the shrinkage and reticulation of the iron phosphate glass network. The average thermal expansion coefficient reduces from 19.8 × 10-6 K-1 to 13.4 × 10-6 K-1, when 25 wt. % of Cs2O was replaced by 25 wt. % of BaO in caesium loaded iron phosphate glass. In addition to the above bulk properties, the role of Ba as a network modifier in the structure of iron phosphate glass is examined using various spectroscopic techniques. The FeII content and average coordination number of iron in the glass network was estimated using Mössbauer spectroscopy. The FeII content in the un-doped iron phosphate glass and barium doped iron phosphate glasses was 20, 21 and 22 ± 1% respectively and the average Fe coordination varied from 5.3 ± 0.2 to 5.7 ± 0.2 with increasing Ba content. The atomic scale structure was further probed by Fe K-edge X-ray absorption spectroscopy. The average coordination number provided by extended X-ray absorption fine structure spectroscopy and X-ray absorption near edge structure was in good agreement with that given by the Mössbauer data.

Preferential Eu Site Occupation and Its Consequences in the Ternary Luminescent Halides AB 2 I 5 : Eu 2 + ( A = Li – Cs ; B = Sr , Ba)

DOE PAGES

Fang, C.  M.; Biswas, Koushik

2015-07-22

Several rare-earth-doped, heavy-metal halides have recently been identified as potential next-generation luminescent materials with high efficiency at low cost. AB 2I 5:Eu 2+ (A=Li–Cs; B=Sr, Ba) is one such family of halides. Its members, such as CsBa 2I 5:Eu 2+ and KSr 2I 5:Eu 2+, are currently being investigated as high-performance scintillators with improved sensitivity, light yield, and energy resolution less than 3% at 662 keV. Within the AB 2I 5 family, our first-principles-based calculations reveal two remarkably different trends in Eu site occupation. The substitutional Eu ions occupy both eightfold-coordinated B1(VIII) and the sevenfold-coordinated B2(VII) sites in the Sr-containingmore » compounds. However, in the Ba-containing crystals, Eu ions strongly prefer the B2(VII)sites. This random versus preferential distribution of Eu affects their electronic properties. The calculations also suggest that in the Ba-containing compounds one can expect the formation of Eu-rich domains. These results provide atomistic insight into recent experimental observations about the concentration and temperature effects in Eu-doped CsBa 2I 5. We discuss the implications of our results with respect to luminescent properties and applications. We also hypothesize Sr, Ba-mixed quaternary iodides ABa VIIISr VIII 5:Eu as scintillators having enhanced homogeneity and electronic properties.« less

Metals detected by ICP/MS in wound tissue of war injuries without fragments in Gaza

PubMed Central

2010-01-01

Background The amount and identity of metals incorporated into "weapons without fragments" remain undisclosed to health personnel. This poses a long-term risk of assumption and contributes to additional hazards for victims because of increased difficulties with clinical management. We assessed if there was evidence that metals are embedded in "wounds without fragments" of victims of the Israeli military operations in Gaza in 2006 and 2009. Methods Biopsies of "wounds without fragments" from clinically classified injuries, amputation (A), charred (C), burns (B), multiple piercing wounds by White Phosphorus (WP) (M), were analyzed by ICP/MS for content in 32 metals. Results Toxic and carcinogenic metals were detected in folds over control tissues in wound tissues from all injuries: in A and C wounds (Al, Ti, Cu, Sr, Ba, Co, Hg, V, Cs and Sn), in M wounds (Al, Ti, Cu, Sr, Ba, Co and Hg) and in B wounds (Co, Hg, Cs, and Sn); Pb and U in wounds of all classes; B, As, Mn, Rb, Cd, Cr, Zn in wounds of all classes, but M; Ni was in wounds of class A. Kind and amounts of metals correlate with clinical classification of injuries, exposing a specific metal signature, similar for 2006 and 2009 samples. Conclusions The presence of toxic and carcinogenic metals in wound tissue is indicative of the presence in weapon inducing the injury. Metal contamination of wounds carries unknown long term risks for survivors, and can imply effects on populations from environmental contamination. We discuss remediation strategies, and believe that these data suggest the need for epidemiological and environmental surveys. PMID:20579349

Refractivity of Molten Nitrates and Chlorides: Binary Mixtures Containing Cesium Ions

NASA Astrophysics Data System (ADS)

Uchiyama, Yohji; Karawacki, Ernest

1981-05-01

By using an interferometric technique, the refractive index of some molten salt mixtures containing Cs+ ions was measured with high accuracy: (Li-Cs)NO3, (Na-Cs)NO3, (Ag-Cs)NO3, (Li-Cs)Cl, and also pure RbCl. The isotherms of molar refractivity show a small negative deviation from additivity in the (Li-Cs)NO3 and (Li-Cs)Cl systems and a positive deviation in the (Ag-Cs)NO3 mixture. A tentative attempt was made to relate the excess molar refractivities with the absorption bands of the ions.

Impact and Timing of Bilateral Adrenalectomy for Refractory ACTH-Dependent Cushing’s Syndrome

PubMed Central

Morris, Lilah F.; Harris, Rachel S.; Milton, Denái R.; Waguespack, Steven G.; Habra, Mouhammed A.; Jimenez, Camilo; Vassilopoulou-Sellin, Rena; Lee, Jeffrey E.; Perrier, Nancy D.; Grubbs, Elizabeth G.

2014-01-01

Introduction In patients with refractory ACTH-dependent Cushing’s syndrome (CS), we evaluated steroidogenesis inhibition (SI) and bilateral adrenalectomy (BA) to predict which patients might benefit most from each treatment modality. Methods Clinical data from patients treated 1970-2012 were retrospectively reviewed by treatment group (SI or SI+BA). Validated severity scales were used to calculate metabolic (M) score (hypokalemia, hyperglycemia, hypertension, proximal muscle weakness) and adverse events (AE) score (thrombosis, fracture, infection). Results 65 patients (16 pituitary, 49 ectopic) were treated with SI+BA (n=21,32%) or SI alone (n=44,68%). Presenting M scores and source of ACTH excess (ectopic vs. pituitary) were similar. Both groups improved metabolically after treatment. 39% of AEs in the SI+BA group occurred within 12 months of presentation. 24(55%) SI patients died (median survival 24.0 months); steroid excess contributed to 71%. Six SI+BA patients died (29%), including all 3 patients with recurrent CS after BA. Minor perioperative complications occurred in 7 patients (33%). Conclusions Post-treatment M and AE scores improved for all patients and 70% of AEs occurred in SI+BA patients within 12 months of presentation, emphasizing the importance of early surgical intervention. These data argue for the safety and efficacy of early BA in selected patients with uncontrollable CS. PMID:24383115

A new oxytelluride: Perovskite and CsCl intergrowth in Ba 3Yb 2O 5Te

DOE PAGES

Whalen, J. B.; Besara, T.; Vasquez, R.; ...

2013-04-27

The new oxytelluride Ba 3Yb 2O 5Te was obtained from an alkaline earth flux. Ba3Yb2O5Te crystallizes in the tetragonal space group P4/ mmm (#123), with a=4.3615(3) Å and c=11.7596(11) angstrom, Z=1. The structure combines two distinct building blocks, a Ba 2Yb 2O 5 perovskite-like double layer with square bipyramidal coordination of the ytterbium ions, and a CsCl-type BaTe layer. Short range magnetic order is apparent at below 5 K, with the magnetic behavior above this temperature dominated by crystal field effects. The structure may be considered as an analog to the Ruddlesden-Popper phases, where the NaCl-type layer has been replacedmore » by the CsCl-type layer. Finally, the two-dimensional magnetic behavior is expected based on the highly anisotropic nature of the structure.« less

Minor and potentially toxic trace elements in milk and blood serum of dairy donkeys.

PubMed

Fantuz, F; Ferraro, S; Todini, L; Piloni, R; Mariani, P; Malissiova, E; Salimei, E

2015-08-01

The aim of this trial was to study the concentration of Ti, V, As, Rb, Sr, Mo, Cd, Cs, and Pb in donkey milk and blood serum. One hundred twelve individual milk and blood serum samples were collected from 16 lactating donkeys (Martina-Franca-derived population; 6 to 12 yr old; 3 to 7 parities; average live weight 205.4kg; 32 to 58 d after foaling at the beginning of the trial) during a 3-mo-long experiment. The samples were analyzed for the aforementioned elements by inductively coupled plasma-mass spectrometry. Feedstuff and drinking water were also analyzed for the investigated elements. Data were processed by ANOVA for repeated measures. Average milk concentrations (±SD) of Ti, Rb, Sr, Mo, Cs, and Pb were 77.3 (±7.7), 339.1 (±82.1), 881.7 (±270.4), 4.5 (±1.6), 0.49 (±0.09), and 3.2 (±2.7) μg/L, respectively. More than 80% of samples were below the limit of detection for V, As, and Cd in milk and for Cd, and Pb in blood serum. The lower bound calculated for milk V, As, and Cd was 0.03μg/L for the 3 elements, the upper bound was calculated at 0.23, 0.10, and 0.31μg/L and the maximum value was observed at 0.54, 0.15, and 0.51μg/L, respectively. The average milk concentrations of Ti, Rb, Sr, Mo, and Cs were 600, 458, 346, 16, and 294%, respectively, than those of blood serum. Yet, Cs concentrations were in the same order of magnitude in milk and serum. Moderate to strong positive and significant correlation coefficients were observed between milk and blood serum concentrations for Ti, Rb, Sr, and Cs. The effect of the stage of lactation was significant for all the investigated elements in milk and blood serum, but most of the elements showed only small changes or inconsistent trends, and only the concentrations of Rb and Sr showed decreasing trends both in milk and blood serum. The relationship between milk and blood serum element concentrations indicates that the mammary gland plays a role in determining the milk concentrations of Mo, Ti, Rb, Sr, Mo, and Cs. In the current experimental conditions, in agreement with the low levels in drinking water and feedstuff, donkey milk concentration of potentially toxic elements was very low and did not raise health concerns for human consumption. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Biomonitoring of 33 Elements in Blood and Urine Samples from Coastal Populations in Sanmen County of Zhejiang Province.

PubMed

Zhang, Su-jing; Luo, Ru-xin; Ma, Dong; Zhuo, Xian-yi

2016-04-01

To determine the normal reference values of 33 elements, Ag, Al, As, Au, B, Ba, Be, Ca, Cd, Co, Cr, Cs, Cu, Fe, Ga, Hg, Li, Mg, Mn, Mo, Ni, Pb, Rb, Sb, Se, Sr, Th, Ti, Tl, U, V, Zn and Zr, in the blood and urine samples from the general population in Sanmen County of Zhejiang province, a typical coastal area of eastern China. The 33 elements in 272 blood and 300 urine samples were determined by inductively coupled plasma-mass spectrometry (ICP-MS). The normality test of data was conducted using SPSS 17.0 Statistics. The data was compared with other reports. The normal reference values of the 33 elements in the blood and urine samples from the general population in Sanmen County were obtained, which of some elements were found to be similar with other reports, such as Co, Cu, Mn and Sr, while As, Cd, Hg and Pb were generally found to be higher than those previously reported. There was a wide variation between the reports from different countries in blood Ba. The normal reference values of the 33 elements in the blood and urine samples from the general population in Sanmen County are established, and successfully applied to two poisoning cases.

Unusual centrosymmetric structure of [M(18-crown-6)](+) (M = Rb, Cs and NH4) complexes stabilized in an environment of hexachloridoantimonate(V) anions.

PubMed

Ponomarova, Vira V; Rusanova, Julia A; Rusanov, Eduard B; Domasevitch, Konstantin V

2015-10-01

In (1,4,7,10,13,16-hexaoxacyclooctadecane)rubidium hexachloridoantimonate(V), [Rb(C12H24O6)][SbCl6], (1), and its isomorphous caesium {(1,4,7,10,13,16-hexaoxacyclooctadecane)caesium hexachloridoantimonate(V), [Cs(C12H24O6)][SbCl6]}, (2), and ammonium {ammonium hexachloridoantimonate(V)-1,4,7,10,13,16-hexaoxacyclooctadecane (1/1), (NH4)[SbCl6]·C12H24O6}, (3), analogues, the hexachloridoantimonate(V) anions and 18-crown-6 molecules reside across -3 axes passing through the Sb atoms and the centroids of the 18-crown-6 groups, both of which coincide with centres of inversion. The Rb(+) [in (1)], Cs(+) [in (2)] and NH4(+) [in (3)] cations are situated inside the cavity of the 18-crown-6 ring; they are situated on -3 axes and are equally disordered about centres of inversion, deviating from the centroid of the 18-crown-6 molecule by 0.4808 (13), 0.9344 (7) and 0.515 (8) Å, respectively. Interaction of the ammonium cation and the 18-crown-6 group is supported by three equivalent hydrogen bonds [N...O = 2.928 (3) Å and N-H...O = 162°]. The centrosymmetric structure of [Cs(18-crown-6)](+), with the large Cs(+) cation approaching the centre of the ligand cavity, is unprecedented and accompanied by unusually short Cs-O bonds [2.939 (2) and 3.091 (2) Å]. For all three compounds, the [M(18-crown-6)](+) cations and [SbCl6](-) anions afford linear stacks along the c axis, with the cationic complexes embedded between pairs of inversion-related anions.

gA-driven shapes of electron spectra of forbidden β decays in the nuclear shell model

NASA Astrophysics Data System (ADS)

Kostensalo, Joel; Suhonen, Jouni

2017-08-01

The evolution of the shape of the electron spectra of 16 forbidden β- decays as a function of gA was studied using the nuclear shell model in appropriate single-particle model spaces with established, well-tested nuclear Hamiltonians. The β spectra of 94Nb(6+) →94Mo(4+) and 98Tc(6+) →98Ru(4+) were found to depend strongly on gA, which makes them excellent candidates for the determination of the effective value of gA with the spectrum-shape method (SSM). A strong gA dependence is also seen in the spectrum of 96Zr(0+) →96Nb(6+) . This decay could be used for determining the quenching of gA in sixth-forbidden decays in the future, when the measurement of the spectrum becomes experimentally feasible. The calculated shell-model electron spectra of the ground-state-to-ground-state decays of 87Rb, 99Tc, and 137Cs and the decay of 137Cs to the isomeric 11 /2- state in 137Ba were found to be in excellent agreement with the spectra previously calculated using the microscopic quasiparticle-phonon model. This is further evidence of the robust nature of the SSM observed in the previous studies.

Rich structural chemistry in new alkali metal yttrium tellurites: three-dimensional frameworks of NaYTe4O10, KY(TeO3)2, RbY(TeO3)2, and a novel variant of hexagonal tungsten bronze, CsYTe3O8.

PubMed

Kim, Youngkwon; Lee, Dong Woo; Ok, Kang Min

2015-01-05

Pure polycrystalline phases and single crystals of four new quaternary alkali metal yttrium tellurites, NaYTe4O10, KY(TeO3)2, RbY(TeO3)2, and CsYTe3O8, have been prepared by solid-state and hydrothermal reactions using A2CO3 (A = Na, K, Rb, and Cs), Y(NO3)3·6H2O, Y2O3, and TeO2 as starting reagents. X-ray diffraction analyses suggest that NaYTe4O10 exhibits a highly symmetric three-dimensional (3D) framework consisting of YO8 square antiprisms and chains of TeO4 polyhedra. Within the framework, six- (6-) and eight-membered ring (8-MR) channels are observed. KY(TeO3)2 and RbY(TeO3)2 are isostructural to each other and reveal another 3D framework with structures containing YO6 octahedra and TeO3 trigonal pyramids with 4-MR and 12-MR channels. CsYTe3O8 shows a hexagonal tungsten bronze (HTB)-like topology composed of hexagonal tungsten oxide-like layers of TeO4 polyhedra and YO6 octahedral linkers with 3-MR and 6-MR channels. Thermal analyses, elemental analyses, and spectroscopic characterizations, such as UV-vis diffuse reflectance and infrared spectra, are presented, as are local dipole moment calculations for the constituent asymmetric polyhedra TeO3 and TeO4.

Spectroelectrochemistry of EuCl 3 in Four Molten Salt Eutectics; 3 LiCl−NaCl, 3 LiCl−2 KCl, LiCl−RbCl, and 3 LiCl−2 CsCl; at 873 K

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

Schroll, Cynthia A.; Chatterjee, Sayandev; Levitskaia, Tatiana

Key electrochemical properties affecting pyroprocessing of nuclear fuel were examined in four eutectic melts using using Eu3+/2+ as a representative probe. We report the electrochemical and spectroelectrochemical behavior of EuCl3 in four molten salt eutectics (3 LiCl – NaCl, 3 LiCl – 2 KCl, LiCl – RbCl and 3 LiCl – 2 CsCl) at 873 K. Cyclic voltammetry was used to determine the redox potential for Eu3+/2+ and the applied potentials for spectroelectrochemistry. Single step chronoabsorptometry and thin-layer spectroelectrochemistry were used to obtain the number of electrons transferred, redox potentials and diffusion coefficients for Eu3+ in each eutectic melt. Themore » redox potentials determined by thin-layer spectroelectrochemistry were extremely close to those obtained using cyclic voltammetry. The redox potential for Eu3+/2+ was most positive in the 3 LiCl - NaCl melt, showed a negative shift in the 3 LiCl - 2 KCl melt, and was the most negative in the LiCl - RbCl and 3 LiCl - 2 CsCl eutectics. The diffusion coefficient for Eu3+ followed this same trend; it was the largest in the 3 LiCl - NaCl melt and the smallest in the LiCl - RbCl and 3 LiCl - 2 CsCl melts. The basic one-electron reversible electron transfer for Eu3+/2+ was not changed by melt composition.« less

Bronchoarterial ratio in never-smokers adults: Implications for bronchial dilation definition.

PubMed

Diaz, Alejandro A; Young, Thomas P; Maselli, Diego J; Martinez, Carlos H; Maclean, Erick S; Yen, Andrew; Dass, Chandra; Simpson, Scott A; Lynch, David A; Kinney, Gregory L; Hokanson, John E; Washko, George R; San José Estépar, Raul

2017-01-01

Bronchiectasis manifests as recurrent respiratory infections and reduced lung function. Airway dilation, which is measured as the ratio of the diameters of the bronchial lumen (B) and adjacent pulmonary artery (A), is a defining radiological feature of bronchiectasis. A challenge to equating the bronchoarterial (BA) ratio to disease severity is that the diameters of airway and vessel in health are not established. We sought to explore the variability of BA ratio in never-smokers without pulmonary disease and its associations with lung function. Objective measurements of the BA ratio on volumetric computed tomography (CT) scans and pulmonary function data were collected in 106 never-smokers. The BA ratio was measured in the right upper lobe apical bronchus (RB1) and the right lower lobe basal posterior bronchus. The association between the BA ratio and forced expiratory volume in 1 s (FEV 1 ) was assessed using regression analysis. The BA ratio was 0.79 ± 0.16 and was smaller in more peripheral RB1 bronchi (P < 0.0001). The BA ratio was >1, a typical threshold for bronchiectasis, in 10 (8.5%) subjects. Subjects with a BA ratio >1 versus ≤1 had smaller artery diameters (P < 0.0001) but not significantly larger bronchial lumens. After adjusting for age, gender, race and height, the BA ratio was directly related to FEV 1 (P = 0.0007). In never-smokers, the BA ratio varies by airway generation and is associated with lung function. A BA ratio >1 is driven by small arteries. Using artery diameter as reference to define bronchial dilation seems inappropriate. © 2016 Asian Pacific Society of Respirology.

Interactions and low-energy collisions between an alkali ion and an alkali atom of a different nucleus

NASA Astrophysics Data System (ADS)

Rakshit, Arpita; Ghanmi, Chedli; Berriche, Hamid; Deb, Bimalendu

2016-05-01

We study theoretically interaction potentials and low-energy collisions between different alkali atoms and alkali ions. Specifically, we consider systems such as X + {{{Y}}}+, where X({{{Y}}}+) is either Li(Cs+) or Cs(Li+), Na(Cs+) or Cs(Na+) and Li(Rb+) or Rb(Li+). We calculate the molecular potentials of the ground and first two excited states of these three systems using a pseudopotential method and compare our results with those obtained by others. We derive ground-state scattering wave functions and analyze the cold collisional properties of these systems for a wide range of energies. We find that, in order to get convergent results for the total scattering cross sections for energies of the order 1 K, one needs to take into account at least 60 partial waves. The low-energy scattering properties calculated in this paper may serve as a precursor for experimental exploration of quantum collisions between an alkali atom and an alkali ion of a different nucleus.

Binary Alkali-Metal Silicon Clathrates by Spark Plasma Sintering: Preparation and Characterization

PubMed Central

Veremchuk, Igor; Beekman, Matt; Antonyshyn, Iryna; Schnelle, Walter; Baitinger, Michael; Nolas, George S.; Grin, Yuri

2016-01-01

The binary intermetallic clathrates K8-xSi46 (x = 0.4; 1.2), Rb6.2Si46, Rb11.5Si136 and Cs7.8Si136 were prepared from M4Si4 (M = K, Rb, Cs) precursors by spark-plasma route (SPS) and structurally characterized by Rietveld refinement of PXRD data. The clathrate-II phase Rb11.5Si136 was synthesized for the first time. Partial crystallographic site occupancy of the alkali metals, particularly for the smaller Si20 dodecahedra, was found in all compounds. SPS preparation of Na24Si136 with different SPS current polarities and tooling were performed in order to investigate the role of the electric field on clathrate formation. The electrical and thermal transport properties of K7.6Si46 and K6.8Si46 in the temperature range 4–700 K were investigated. Our findings demonstrate that SPS is a novel tool for the synthesis of intermetallic clathrate phases that are not easily accessible by conventional synthesis techniques. PMID:28773710

Heavier alkali-metal monosulfides (KS, RbS, CsS, and FrS) and their cations.

PubMed

Lee, Edmond P F; Wright, Timothy G

2005-10-08

The heavier alkali-metal monosulfides (KS, RbS, CsS, and FrS) have been studied by high-level ab initio calculations. The RCCSD(T) method has been employed, combined with large flexible valence basis sets. All-electron basis sets are used for potassium and sulfur, with effective core potentials being used for the other metals, describing the core electrons. Potential-energy curves are calculated for the lowest two neutral and cationic states: all neutral monosulfide species have a (2)Pi ground state, in contrast with the alkali-metal monoxide species, which undergo a change in the electronic ground state from (2)Pi to (2)Sigma(+) as the group is descended. In the cases of KS, RbS, and CsS, spin-orbit curves are also calculated. We also calculate potential-energy curves for the lowest (3)Sigma(-) and (3)Pi states of the cations. From the potential-energy curves, spectroscopic constants are derived, and for KS the spectroscopic results are compared to experimental spectroscopic values. Ionization energies, dissociation energies, and heats of formation are also calculated; for KS, we explore the effects of relativity and basis set extrapolation on these values.

Rydberg-Ritz analysis and quantum defects for Rb and Cs atoms on helium nanodroplets

NASA Astrophysics Data System (ADS)

Lackner, Florian; Krois, Günter; Ernst, Wolfgang E.

2013-08-01

A Rydberg-Ritz approach is used for the interpretation of Rb-He? and Cs-He? Rydberg states and Rydberg series. Variations of the quantum defects within a Rydberg series give insight into the interaction between the alkali atom's valence electron and the superfluid helium droplet. A screening of the valence electron from the alkali atom core by the helium droplet is observed for high Rydberg states. For states with lower principal quantum number, the effect decreases and the quantum defects are found to lie closer to free atom values, indicating an increased probability for the electron to be found inside the alkali atom core. An investigation of the spin-orbit splitting of the Cs-He? nP(2Π) components reveals that the splitting of the lowest 2Π states is more atom-like [Hund's case (c) coupling] than at higher n states [Hund's case (a) coupling]. In addition, we report a detailed study of the droplet size dependence of Ak-He? Rydberg series on the example of the Rb-He? D(Δ) series. Higher Rydberg states of this series are strongly redshifted, which is also related to the screening effect.

Effect of Rb2O and Cs2O on Inclusion Removal in 321 Stainless Steels Using Novel Basic Tundish Fluxes

NASA Astrophysics Data System (ADS)

Choi, Kyunsuk; Kang, Youngjo; Sohn, Il

2016-06-01

Inclusion removal and modification of the 321 stainless steel using Rb2O- and Cs2O-containing novel basic tundish flux has been investigated. The average inclusion diameter was significantly lowered after reaction of the liquid metal with the flux after 45 minutes in an induction furnace set at 1823 K (1550 °C) under an Ar atmosphere. The number of inclusions was also decreased with increased reaction time and the majority of the inherent TiN inclusions were removed after reaction with the proposed novel basic tundish flux. Spinel inclusions were also observed after the reaction, which was due to the reaction of the MgO crucible and the CaO-Al2O3-SiO2-MgO-` x'wt pct R2O flux system at fixed CaO/(Al2O3 + SiO2) of 1.45. The Rb2O and Cs2O seemed to have allowed significant removal of the TiN inclusions due to its ion compensation effect and the supplement of free oxygen ions, while increasing the viscosity of the slag to retain the absorbed inclusions.

Excitation functions for (d,x) reactions on (133)Cs up to Ed=40MeV.

PubMed

Tárkányi, F; Ditrói, F; Takács, S; Hermanne, A; Baba, M; Ignatyuk, A V

2016-04-01

In the frame of a systematic study of excitation functions of deuteron induced reactions the excitation functions of the (133)Cs(d,x)(133m,133mg,131mg)Ba,(134,)(132)Cs and (12)(9m)Xe nuclear reactions were measured up to 40MeV deuteron energies by using the stacked foil irradiation technique and γ-ray spectroscopy of activated samples. The results were compared with calculations performed with the theoretical nuclear reaction codes ALICE-IPPE-D, EMPIRE II-D and TALYS calculation listed in the TENDL-2014 library. A moderate agreement was obtained. Based on the integral yields deduced from our measured cross sections, production of (131)Cs via the (133)Cs(d,4n)(131)Ba→(131)Cs reaction and (133)Ba via (133)Cs(d,2n) reactions is discussed in comparison with other charged particle production routes. Copyright © 2016 Elsevier Ltd. All rights reserved.

The polarization and the fundamental sensitivity of 39K (133Cs)-85Rb-4He hybrid optical pumping spin exchange relaxation free atomic magnetometers.

PubMed

Liu, Jian-Hua; Jing, Dong-Yang; Wang, Liang-Liang; Li, Yang; Quan, Wei; Fang, Jian-Cheng; Liu, Wu-Ming

2017-07-28

The hybrid optical pumping spin exchange relaxation free (SERF) atomic magnetometers can realize ultrahigh sensitivity measurement of magnetic field and inertia. We have studied the 85 Rb polarization of two types of hybrid optical pumping SERF magnetometers based on 39 K- 85 Rb- 4 He and 133 Cs- 85 Rb- 4 He respectively. Then we found that 85 Rb polarization varies with the number density of buffer gas 4 He and quench gas N 2 , pumping rate of pump beam and cell temperature respectively, which will provide an experimental guide for the design of the magnetometer. We obtain a general formula on the fundamental sensitivity of the hybrid optical pumping SERF magnetometer due to shot-noise. The formula describes that the fundamental sensitivity of the magnetometer varies with the number density of buffer gas and quench gas, the pumping rate of pump beam, external magnetic field, cell effective radius, measurement volume, cell temperature and measurement time. We obtain a highest fundamental sensitivity of 1.5073 aT/Hz 1/2 (1 aT = 10 -18 T) with 39 K- 85 Rb- 4 He magnetometer between above two types of magnetometers when 85 Rb polarization is 0.1116. We estimate the fundamental sensitivity limit of the hybrid optical pumping SERF magnetometer to be superior to 1.8359 × 10 -2 aT/Hz 1/2 , which is higher than the shot-noise-limited sensitivity of 1 aT/Hz 1/2 of K SERF atomic magnetometer.

Specific cesium transport via the Escherichia coli Kup (TrkD) K+ uptake system.

PubMed Central

Bossemeyer, D; Schlösser, A; Bakker, E P

1989-01-01

Escherichia coli cells which contain a functional Kup (formerly TrkD) system took up Cs+ with a moderate rate and affinity. Kup is a separate K+ uptake system with relatively little discrimination in the transport of the cations K+, Rb+, and Cs+. Regardless of the presence or absence of Kup, K+-replete cells took up Cs+ primarily by a very low affinity mode, proportional to the ratio of the Cs+ and K+ concentrations in the medium. PMID:2649491

Major and trace elements in organically or conventionally produced milk.

PubMed

Hermansen, John E; Badsberg, Jens H; Kristensen, Troels; Gundersen, Vagn

2005-08-01

A total of 480 samples of milk from 10 organically and 10 conventionally producing dairy farms in Denmark and covering 8 sampling periods over 1 year (triplicate samplings) were analysed for 45 trace elements and 6 major elements by high-resolution inductively coupled plasma mass spectrometry and inductively coupled plasma atomic emission spectrometry. Sampling, sample preparation, and analysis of the samples were performed under carefully controlled contamination-free conditions. The dairy cattle breeds were Danish-Holstein or Jersey. Sources of variance were quantified, and differences between production systems and breeds were tested. The major source of variation for most elements was week of sampling. Concentrations of Al, Cu, Fe, Mo, Rb, Se, and Zn were within published ranges. Concentrations of As, Cd, Cr, Mn and Pb were lower, and concentrations of Co and Sr were higher than published ranges. Compared with Holsteins, Jerseys produced milk with higher concentrations of Ba, Ca, Cu, Fe, Mg, Mn, Mo, P, Rh, and Zn and with a lower concentration of Bi. The organically produced milk, compared with conventionally produced milk, contained a significantly higher concentration of Mo (48 v. 37 ng/g) and a lower concentration of Ba (43 v. 62 ng/g), Eu (4 v. 7 ng/g), Mn (16 v. 20 ng/g) and Zn (4400 v. 5150 ng/g respectively). The investigation yielded typical concentrations for the following trace elements in milk, for which no or very few data are available: Ba, Bi, Ce, Cs, Eu, Ga, Gd, In, La, Nb, Nd, Pd, Pr, Rh, Sb, Sm, Tb, Te, Th, Ti, Tl, U, V, Y, and Zr.

New insights into trace elements deposition in the snow packs at remote alpine glaciers in the northern Tibetan Plateau, China.

PubMed

Dong, Zhiwen; Kang, Shichang; Qin, Xiang; Li, Xiaofei; Qin, Dahe; Ren, Jiawen

2015-10-01

Trace element pollution resulting from anthropogenic emissions is evident throughout most of the atmosphere and has the potential to create environmental and health risks. In this study we investigated trace element deposition in the snowpacks at two different locations in the northern Tibetan Plateau, including the Laohugou (LHG) and the Tanggula (TGL) glacier basins, and its related atmospheric pollution information in these glacier areas, mainly focusing on 18 trace elements (Li, Be, V, Cr, Co, Ni, Cu, Zn, Ga, Rb, Nb, Mo, Cd, Sb, Cs, Ba, Tl, and Pb). The results clearly demonstrate that pronounced increases of both concentrations and crustal enrichment factors (EFs) are observed in the snowpack at the TGL glacier basin compared to that of the LHG glacier basin, with the highest EFs for Sb and Zn in the TGL basin, whereas with the highest EFs for Sb and Cd in the LHG basin. Compared with other studies in the Tibetan Plateau and surrounding regions, trace element concentration showed gradually decreasing trend from Himalayan regions (southern Tibetan Plateau) to the TGL basin (central Tibetan Plateau), and to the LHG basin (northern Tibetan Plateau), which probably implied the significant influence of atmospheric trace element transport from south Asia to the central Tibetan Plateau. Moreover, EF calculations at two sites showed that most of the heavy metals (e.g., Cu, Zn, Mo, Cd, Sb, and Pb) were from anthropogenic sources and some other elements (e.g., Li, Rb, and Ba) were mainly originated from crustal sources. MODIS atmospheric optical depth (AOD) fields derived using the Deep Blue algorithm and CALIOP/CALIPSO transect showed significant influence of atmospheric pollutant transport from south Asia to the Tibetan Plateau, which probably caused the increased concentrations and EFs of trace element deposition in the snowpack on the TGL glacier basin. Copyright © 2015 Elsevier B.V. All rights reserved.

Superconductivity in Hydrides Doped with Main Group Elements Under Pressure

NASA Astrophysics Data System (ADS)

Shamp, Andrew; Zurek, Eva

2017-01-01

A priori crystal structure prediction techniques have been used to explore the phase diagrams of hydrides of main group elements under pressure. A number of novel phases with the chemical formulas MHn, n > 1 and M = Li, Na, K, Rb, Cs; MHn, n > 2 and M= Mg, Ca, Sr, Ba; HnI with n > 1 and PH, PH2, PH3 have been predicted to be stable at pressures achievable in diamond anvil cells. The hydrogenic lattices within these phases display a number of structural motifs including H2δ- , H-, H-3 , as well as one-dimensional and three-dimensional extended structures. A wide range of superconducting critical temperatures, Tcs, are predicted for these hydrides. The mechanism of metallization and the propensity for superconductivity are dependent upon the structural motifs present in these phases, and in particular on their hydrogenic sublattices. Phases that are thermodynamically unstable, but dynamically stable, are accessible experimentally. The observed trends provide insight on how to design hydrides that are superconducting at high temperatures.

Ion exchange selectivity for cross-linked polyacrylic acid

NASA Technical Reports Server (NTRS)

May, C. E.; Philipp, W. H.

1983-01-01

The ion separation factors for 21 common metal ions with cross-linked polyacrylic acid were determined as a function of pH and the percent of the cross-linked polyacrylic acid neutralized. The calcium ion was used as a reference. At a pH of 5 the decreasing order of affinity of the ions for the cross-linked polyacrylic acid was found to be: Hg++, Fe+++, Pb++, Cr+++, Cu++, Cd++, Al+++, Ag+, Zn++, Ni++, Mn++, Co++, Ca++, Sr++, Ba++, Mg++, K+, Rb+, Cs+, Na+, and Li+. Members of a chemical family exhibited similar selectivities. The Hg++ ion appeared to be about a million times more strongly bound than the alkali metal ions. The relative binding of most of the metal ions varied with pH; the very tightly and very weakly bound ions showed the largest variations with pH. The calcium ion-hydrogen ion equilibrium was perturbed very little by the presence of the other ions. The separation factors and selectivity coefficients are discussed in terms of equilibrium and thermodynamic significance.

Multielement analysis of Canadian wines by inductively coupled plasma mass spectrometry (ICP-MS) and multivariate statistics.

PubMed

Taylor, Vivien F; Longerich, Henry P; Greenough, John D

2003-02-12

Trace element fingerprints were deciphered for wines from Canada's two major wine-producing regions, the Okanagan Valley and the Niagara Peninsula, for the purpose of examining differences in wine element composition with region of origin and identifying elements important to determining provenance. Analysis by ICP-MS allowed simultaneous determination of 34 trace elements in wine (Li, Be, Mg, Al, P, Cl, Ca, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Br, Rb, Sr, Mo, Ag, Cd, Sb, I, Cs, Ba, La, Ce, Tl, Pb, Bi, Th, and U) at low levels of detection, and patterns in trace element concentrations were deciphered by multivariate statistical analysis. The two regions were discriminated with 100% accuracy using 10 of these elements. Differences in soil chemistry between the Niagara and Okanagan vineyards were evident, without a good correlation between soil and wine composition. The element Sr was found to be a good indicator of provenance and has been reported in fingerprinting studies of other regions.

Surface structure in simple liquid metals: An orbital-free first-principles study

NASA Astrophysics Data System (ADS)

González, D. J.; González, L. E.; Stott, M. J.

2006-07-01

Molecular dynamics simulations of the liquid-vapor interfaces in simple sp-bonded liquid metals have been performed using first-principles methods. Results are presented for liquid Li, Na, K, Rb, Cs, Mg, Ba, Al, Tl, and Si at thermodynamic conditions near their respective triple points, for samples of 2000 particles in a slab geometry. The longitudinal ionic density profiles exhibit a pronounced stratification extending several atomic diameters into the bulk, which is a feature already experimentally observed in liquid K, Ga, In, Sn, and Hg. The wavelength of the ionic oscillations shows a good scaling with the radii of the associated Wigner-Seitz spheres. The structural rearrangements at the interface are analyzed in terms of the transverse pair correlation function, the coordination number, and the bond-angle distribution between nearest neighbors. The valence electronic density profile also shows (weaker) oscillations whose phase, with respect to those of the ionic profile, changes from opposite phase in the alkalis to almost in-phase for Si.

Consistent van der Waals Radii for the Whole Main Group

PubMed Central

Mantina, Manjeera; Chamberlin, Adam C.; Valero, Rosendo; Cramer, Christopher J.; Truhlar, Donald G.

2013-01-01

Atomic radii are not precisely defined but are nevertheless widely used parameters in modeling and understanding molecular structure and interactions. The van der Waals radii determined by Bondi from molecular crystals and noble gas crystals are the most widely used values, but Bondi recommended radius values for only 28 of the 44 main-group elements in the periodic table. In the present article we present atomic radii for the other 16; these new radii were determined in a way designed to be compatible with Bondi’s scale. The method chosen is a set of two-parameter correlations of Bondi’s radii with repulsive-wall distances calculated by relativistic coupled-cluster electronic structure calculations. The newly determined radii (in Å) are Be, 1.53; B, 1.92; Al, 1.84; Ca, 2.31; Ge, 2.11; Rb, 3.03; Sr, 2.50; Sb, 2.06; Cs, 3.43; Ba, 2.68; Bi, 2.07; Po, 1.97; At, 2.02; Rn, 2.20; Fr, 3.48; and Ra, 2.83. PMID:19382751

Consistent van der Waals radii for the whole main group.

PubMed

Mantina, Manjeera; Chamberlin, Adam C; Valero, Rosendo; Cramer, Christopher J; Truhlar, Donald G

2009-05-14

Atomic radii are not precisely defined but are nevertheless widely used parameters in modeling and understanding molecular structure and interactions. The van der Waals radii determined by Bondi from molecular crystals and data for gases are the most widely used values, but Bondi recommended radius values for only 28 of the 44 main-group elements in the periodic table. In the present Article, we present atomic radii for the other 16; these new radii were determined in a way designed to be compatible with Bondi's scale. The method chosen is a set of two-parameter correlations of Bondi's radii with repulsive-wall distances calculated by relativistic coupled-cluster electronic structure calculations. The newly determined radii (in A) are Be, 1.53; B, 1.92; Al, 1.84; Ca, 2.31; Ge, 2.11; Rb, 3.03; Sr, 2.49; Sb, 2.06; Cs, 3.43; Ba, 2.68; Bi, 2.07; Po, 1.97; At, 2.02; Rn, 2.20; Fr, 3.48; and Ra, 2.83.

Origin Of Pyroxenites From San Jorge And Santa Isabel (Solomon Islands).

NASA Astrophysics Data System (ADS)

Berly, T.

2001-12-01

The Solomon Islands are a NW to SE-trending double chain of islands, the older basement of which was formed by SW-directed subduction of the Pacific Plate beneath the Indo-Australian Plate, between the Eocene and Early Miocene. At 10 Ma, the Ontong Java Plateau (OJP) collided with the Solomon arc, and in response to this collision, a polarity reversal of subduction occurred; NE-directed subduction beneath the Solomon arc began. Consequent to this collision, thin fault slices of peridotites, pyroxenites, gabbros, and basalts, some of which are demonstrably obducted OJP, are now exposed in SE Santa Isabel and neighbouring San Jorge. The pyroxenites are associated with harzburgites, dunites and sometimes incorporated into serpentine massifs (NW San Jorge). These fresh, coarse-grained rocks contain variable proportions of orthopyroxene (70

Selenium and 17 other largely essential and toxic metals in muscle and organ meats of Red Deer (Cervus elaphus)--consequences to human health.

PubMed

Jarzyńska, Grażyna; Falandysz, Jerzy

2011-07-01

Concentrations, composition and interrelationships of selenium and metallic elements (Ag, Ba, Cd, Co, Cr, Cs, Cu, Ga, Mn, Mo, Pb, Rb, Sb, Sr, Tl, V and Zn) have been examined in muscle and organ meats of Red Deer hunted in Poland. The analytical data obtained were also discussed in terms of Se supplementation and deficit to Deer as well as the benefits and risk to humans associated with the essential and toxic metals intake resulting from consumption of Deer meat and products. These elements were determined in 20 adult animals of both sexes that were obtained in the 2000/2001 hunting season from Warmia and Mazury in the north-eastern part of Poland. The whole kidneys contained Ba, Cd, Cr, Ga, Pb, Se, Sr and Tl at statistically greater concentrations than liver or muscle tissue from the same animal. Liver showed statistically greater concentrations of Ag, Co, Cu, Mn and Mo than kidneys or muscle tissue, and muscle tissue was richer in Zn, when compared to the kidneys or liver. Cs and Rb were similarly distributed between all three tissue types, while V was less abundant in liver than kidneys or muscle tissue. There were significant associations between some metallic elements retained in Red Deer demonstrated by Principal Component Analysis (PCA) of the data set. In organ and muscle meats (kidneys, liver and muscle tissue considered together) the first principal component (PC1) was strongly influenced by positively correlated variables describing Se, Ba and Cd and negatively correlated variables describing Ag, Co, Cs, Mn, Pb, Tl and V; PC2, respectively, by Cu, Mn and Mo (+) and Zn (-); PC3 by Ga (+) and PC4 by Sb (+). Selenium occurred in muscle tissue, liver and kidneys at median concentrations of 0.13, 0.19 and 4.0mg/g dry weight, respectively. These values can be defined as marginally deficient (< 0.6mg Se/kg liver dw) or satisfactory (≤ 3.0mg Se/kg kidneys dw) for the amount required to maintain the Deer's body condition and health, depending on the criterion for supplementation used. In terms of human nutritional needs, a relatively high selenium content of kidneys can be beneficial. The muscle meat, liver and kidneys of Red Deer can be considered as a very good source of essential Co, Cr, Cu, Mo, Mn, Se and Zn in the human diet. Lead is generally considered as toxic, and the concentrations found in Red Deer (via the food chain intake) were well below the European Union tolerance limit. Pb from the lead bullets can always create food hygienic problem, if not well recognized during sanitary inspection, and this was noted for one muscle meat sample in this study (5% surveyed). There is no tolerance limit of Cd in game animal meats. The median values of Cd noted in fresh muscle tissue, liver and whole kidneys were 0.07, 0.18, and 3.3mg/kg wet weight, respectively. Cd exists as a chemical element present at trace levels in plants and mushrooms in Deer's food chain in background (uncontaminated) areas. When these are consumed by the Deer, the amount of Cd sequestered with metallothioneins and retained in the organ and muscle meat in this study is low enough to be considered safe for human consumption. Copyright © 2011 Elsevier Ltd. All rights reserved.

Transfer of volatiles and metals from mafic to felsic magmas in composite magma chambers: An experimental study

NASA Astrophysics Data System (ADS)

Guo, Haihao; Audétat, Andreas

2017-02-01

In order to determine the behavior of metals and volatiles during intrusion of mafic magma into the base of silicic, upper crustal magma chambers, fluid-rock partition coefficients (Dfluid/rock) of Li, B, Na, S, Cl, K, Mn, Fe, Rb, Sr, Ba, Ce, Cu, Zn, Ag, Cd, Mo, As, Se, Sb, Te, W, Tl, Pb and Bi were determined experimentally at 2 kbar and 850 °C close to the solidus of mafic magma. In a first step, volatile-bearing mafic glasses were prepared by melting a natural basaltic trachyandesite in the presence of volatile-bearing fluids at 1200 °C/10 kbar in piston cylinder presses. The hydrous glasses were then equilibrated in subsequent experiments at 850 °C/2 kbar in cold-seal pressure vessels, which caused 80-90% of the melt to crystallize. After 0.5-2.0 days of equilibration, the exsolved fluid was trapped by means of in-situ fracturing in the form of synthetic fluid inclusions in quartz. Both the mafic rock residue and the fluid inclusions were subsequently analyzed by laser-ablation ICP-MS for major and trace elements. Reverse experiments were conducted by equilibrating metal-bearing aqueous solutions with rock powder and then trapping the fluid. In two additional experiments, information on relative element mobilities were obtained by reacting fluids that exsolved from crystallizing mafic magma with overlying silicic melts. The combined results suggest that under the studied conditions S, Cl, Cu, Se, Br, Cd and Te are most volatile (Dfluid/rock >10), followed by Li, B, Zn, As, Ag, Sb, Cs, W, Tl, Pb and Bi (Dfluid/rock = 1-10). Less volatile are Na, Mg, K, Ca, Mn, Fe, Rb, Sr, Mo and Rb (Dfluid/rock 0.1-1), and the least fluid-mobile elements are Al, Si, Ti, Zr, Ba and Ce (Dfluid/rock <0.1). This trend is broadly consistent with relative element volatilities determined on natural high-temperature fumarole gases, although some differences exist. Based on the volatility data and measured mineral-melt and sulfide-melt partition coefficients, volatile fluxing in felsic natural samples may be identified by Cu, Se, Te and Cd-enrichment in magmatic sulfides, and by As, Se, Cd and Bi-enrichment in magmatic apatite.

Multi-quantum excitation in optically pumped alkali atom: rare gas mixtures

NASA Astrophysics Data System (ADS)

Galbally-Kinney, K. L.; Rawlins, W. T.; Davis, S. J.

2014-03-01

Diode-pumped alkali laser (DPAL) technology offers a means of achieving high-energy gas laser output through optical pumping of the D-lines of Cs, Rb, and K. The exciplex effect, based on weak attractive forces between alkali atoms and polarizable rare gas atoms (Ar, Kr, Xe), provides an alternative approach via broadband excitation of exciplex precursors (XPAL). In XPAL configurations, we have observed multi-quantum excitation within the alkali manifolds which result in infrared emission lines between 1 and 4 μm. The observed excited states include the 42FJ states of both Cs and Rb, which are well above the two-photon energy of the excitation laser in each case. We have observed fluorescence from multi-quantum states for excitation wavelengths throughout the exciplex absorption bands of Cs-Ar, Cs-Kr, and Cs-Xe. The intensity scaling is roughly first-order or less in both pump power and alkali concentration, suggesting a collisional energy pooling excitation mechanism. Collisional up-pumping appears to present a parasitic loss term for optically pumped atomic systems at high intensities, however there may also be excitation of other lasing transitions at infrared wavelengths.

The effect of age and gender on 38 chemical element contents in human iliac crest investigated by instrumental neutron activation analysis.

PubMed

Zaichick, Sofia; Zaichick, Vladimir

2010-01-01

To understand the role of major, minor, and trace elements in the etiology of bone diseases including osteoporosis, it is necessary to determine the normal levels and age-related changes of bone chemical elements. The effect of age and gender on 38 chemical element contents in intact iliac crest of 84 apparently healthy 15-55 years old women (n=38) and men (n=46) was investigated by neutron activation analysis. Mean values (M+/-SEM) for mass fraction (on dry weight basis) of Ca, Cl, Co, Fe, K, Mg, Mn, Na, P, Rb, Sr, and Zn for both female and male taken together were Ca - 169+/-3g/kg, Cl - 1490+/-43 mg/kg, Co - 0.0073+/-0.0024 mg/kg, Fe - 177+/-24 mg/kg, K - 1820+/-79 mg/kg, Mg - 1840+/-48 mg/kg, Mn - 0.316+/-0.013 mg/kg, Na - 4970+/-87 mg/kg, P - 79.7+/-1.5 g/kg, Rb - 1.89+/-0.22 mg/kg, Sr - 312+/-15 mg/kg, and Zn - 65.9+/-3.4 mg/kg, respectively. The upper limit of mean contents of Cs, Eu, Hg, Sb, Sc, and Se were Cs < or = 0.09 mg/kg, Eu < or = 0.005 mg/kg, Hg < or = 0.005 mg/kg, Sb < or = 0.004 mg/kg, Sc < or = 0.001 mg/kg, and Se < or = 0.1mg/kg, respectively. In all bone samples the contents of Ag, As, Au, Ba, Br, Cd, Ce, Cr, Gd, Hf, La, Lu, Nd, Sm, Ta, Tb, Th, U, Yb, and Zr were under detection limits. The Ca, Mg, and P contents decrease with age, regardless of gender. Higher Ca, Mg, P, and Sr mass fractions as well as lower Fe content are typical of female iliac crest as compared to those in male bone. Copyright 2009 Elsevier GmbH. All rights reserved.

Radiation Doses to Members of the U.S. Population from Ubiquitous Radionuclides in the Body: Part 1, Autopsy and In Vivo Data

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

Watson, David J.; Strom, Daniel J.

This paper is part one of a three-part series investigating annual effective doses to residents of the United States from intakes of ubiquitous radionuclides, including radionuclides occurring naturally, radionuclides whose concentrations are technologically enhanced, and anthropogenic radionuclides. This series of papers explicitly excludes intakes from inhaling 222Rn, 220Rn, and their short-lived decay products; it also excludes intakes of radionuclides in occupational and medical settings. The goal of part one of this work was to review, summarize, and characterize all published and some unpublished data for U.S. residents on ubiquitous radionuclide concentrations in tissues and organs. Forty-five papers and reports weremore » obtained and their data reviewed, and three data sets were obtained via private communication. The 45 radionuclides of interest are the 238U series (14 nuclides), the actinium series (headed by 235U; 11 nuclides), and the 232Th series (11 nuclides); primordial radionuclides 87Rb and 40 K; cosmogenic and fallout radionuclides 14C and 3H; and purely anthropogenic radionuclides 137Cs-137mBa, 129I, and 90Sr-90Y. Measurements judged to be relevant were available for only 15 of these radionuclides: 238U, 235U, 234U, 232Th, 230Th, 228Th, 228Ra, 226Ra, 210Pb, 210Po, 137Cs, 87Rb, 40K, 14C, and 3H. Recent and relevant measurements were not available for 129I and 90Sr-90Y. A total of 11,714 radionuclide concentration measurements were found in one or more tissues or organs from 14 States. Data on age, sex, geographic locations, height, and weight of subjects were available only sporadically. Too often authors did not provide meaningful values of uncertainty of measurements so that variability in data sets is confounded with measurement uncertainty. The following papers detail how these shortcomings are overcome to achieve the goals of the three-part series.« less

The sedimentological changes caused by human impact at the artificial channel of Medjerda-River (Coastal zone of Medjerda, Tunisia)

NASA Astrophysics Data System (ADS)

Benmoussa, Thouraya; Amrouni, Oula; Dezileau, Laurent; Mahé, Gil; Abdeljaouad, Saâdi

2018-04-01

Recent sedimentary and morphological changes at the new mouth of Medjerda-River (Gulf of Tunis) are investigated using a multiproxy approach of sediment cores complited by 210Pbex and 137Cs method dating. The subject of the study is to focus on surveying the sedimentary evolution of Medjerda-Raoued Delta caused by the human intervention in the management of the main tributaries of the Medjerda-River (artificial channel of Henchir Tobias). Sediment cores (CEM-1 and CEM-3) were subjected to both multiproxy approaches (Grain size, geochemical analysis and dating radiometric 210Pbex and 137Cs). The sedimentological analysis of the new deltaic deposits shows a progradation sequence with the silt and clay deposits on the historic sandy substratum. The mean grain size evolution on the old beach profile shows a decreasing trend from backshore (CEM-3) to nearshore (CEM-1). The geochemical results show varying concentrations of chemical elements such as Fe, K, Rb, Nb, Cr, Ti, Ba, Ca, Sr, Zr, V, and potentially toxic metal trace elements such as Pb, Zn and the As. The Principal component Analysis (PCA) applied in the geochemical elements evolution confirms the marine origin of the sand deposits in the basic layers of the two cores. The chronological method (210Pbex and 137Cs) affirms that the first fluvial deposits were set up only after 1950. The sedimentological and geochemical result confirm the actual unless of coarser fluvial supplies under the human activities leading the negative coastal sediment balance and the shoreline retreat as well.

The luminal K+ channel of the thick ascending limb of Henle's loop.

PubMed

Bleich, M; Schlatter, E; Greger, R

1990-01-01

In vitro perfused rat thick ascending limbs of Henle's loop (TAL) were used (n = 260) to analyse the conductance properties of the luminal membrane applying the patch-clamp technique. Medullary (mTAL) and cortical (cTAL) tubule segments were dissected and perfused in vitro. The free end of the tubule was held and immobilized at one edge by a holding pipette kept under continuous suction. A micropositioner was used to insert a patch pipette into the lumen, and a gigaohm seal with the luminal membrane was achieved in 455 instances out of considerably more trials. In approximately 20% of all gigaohm seals recordings of single ionic channels were obtained. We have identified only one single type of K+ channel in these cell-attached and cell-excised recordings. In the cell-attached configuration with KCl or NaCl in the pipette, the channel had a conductance of 60 +/- 6 pS (n = 24) and 31 +/- 7 pS (n = 4) respectively. In cell-free patches with KCl either in the patch pipette or in the bath and with a Ringer-type solution (NaCl) on the opposite side the conductance was 72 +/- 4 pS (n = 37) at a clamp voltage of 0 mV. The permeability was 0.33 +/- 0.02 . 10(-12) cm3/s. The selectivity sequence of this channel was: K+ = Rb+ = NH4+ = Cs+ greater than Li+ much greater than Na+ = 0; the conductance sequence was K+ much greater than Li+ much greater than Rb+ = Cs+ = NH4+ = Na+ = 0. In excised patches Rb+, Cs+ and NH4+ when present in the bath at 145 mmol/l all inhibited K+ currents out of the pipette. The channel kinetics were described by one open (9.5 +/- 1.5 ms, n = 18) and by two closed (1.4 +/- 0.1 and 14 +/- 2 ms) time constants. The open probability of this channel was increased by depolarization. The channel open probability was reduced voltage dependently by Ba2+ (half maximal inhibition at 0 mV: 0.07 mmol/l) from the cytosolic side. Verapamil, diltiazem, quinine and quinidine inhibited at approximately 1 mumol/l -0.1 mmol/l from either side. Similarly, the amino cations lidocaine, tetraethylammonium and choline inhibited at 10-100 mmol/l. The channel was downregulated in its open probability by cytosolic Ca2+ activities greater than 10(-7) mol/l and by adenosine triphosphate greater than or equal to 10(-4) mol/l. The open probability was downregulated by decreasing cytosolic pH (2-fold by a decrease in pH by less than or equal to 0.2 units).(ABSTRACT TRUNCATED AT 400 WORDS)

Involvement of PSMD10, CDK4, and Tumor Suppressors in Development of Intrahepatic Cholangiocarcinoma of Syrian Golden Hamsters Induced by Clonorchis sinensis and N-Nitrosodimethylamine

PubMed Central

Uddin, Md. Hafiz; Choi, Min-Ho; Kim, Woo Ho; Jang, Ja-June; Hong, Sung-Tae

2015-01-01

Background Clonorchis sinensis is a group-I bio-carcinogen for cholangiocarcinoma (CCA). Although the epidemiological evidence links clonorchiasis and CCA, the underlying molecular mechanism involved in this process is poorly understood. In the present study, we investigated expression of oncogenes and tumor suppressors, including PSMD10, CDK4, p53 and RB in C. sinensis induced hamster CCA model. Methods Different histochemical/immunohistochemical techniques were performed to detect CCA in 4 groups of hamsters: uninfected control (Ctrl.), infected with C. sinensis (Cs), ingested N-nitrosodimethylamine (NDMA), and both Cs infected and NDMA introduced (Cs+NDMA). The liver tissues from all groups were analyzed for gene/protein expressions by quantitative PCR (qPCR) and western blotting. Principal Findings CCA was observed in all hamsters of Cs+NDMA group with well, moderate, and poorly differentiated types measured in 21.8% ± 1.5%, 13.3% ± 1.3%, and 10.8% ± 1.3% of total tissue section areas respectively. All CCA differentiations progressed in a time dependent manner, starting from the 8th week of infection. CCA stroma was characterized with increased collagen type I, mucin, and proliferative cell nuclear antigen (PCNA). The qPCR analysis showed PSMD10, CDK4 and p16INK4 were over-expressed, whereas p53 was under-expressed in the Cs+NDMA group. We observed no change in RB1 at mRNA level but found significant down-regulation of RB protein. The apoptosis related genes, BAX and caspase 9 were found downregulated in the CCA tissue. Gene/protein expressions were matched well with the pathological changes of different groups except the NDMA group. Though the hamsters in the NDMA group showed no marked pathological lesions, we observed over-expression of Akt/PKB and p53 genes proposing molecular interplay in this group which might be related to the CCA initiation in this animal model. Conclusions/Significance The present findings suggest that oncogenes, PSMD10 and CDK4, and tumor suppressors, p53 and RB, are involved in the carcinogenesis process of C. sinensis induced CCA in hamsters. PMID:26313366

Production of highly-enriched 134Ba for a reference material for isotope dilution mass spectrometry measurements

DOE PAGES

Horkley, J. J.; Carney, K. P.; Gantz, E. M.; ...

2015-03-17

Isotope dilution mass spectrometry (IDMS) is an analytical technique capable of providing accurate and precise quantitation of trace isotope abundance and assay providing measurement uncertainties below 1 %. To achieve these low uncertainties, the IDMS method ideally utilizes chemically pure “spike” solutions that consist of a single highly enriched isotope that is well-characterized relating to the abundance of companion isotopes and concentration in solution. To address a current demand for accurate 137Cs/137Ba ratio measurements for “age” determination of radioactive 137Cs sources, Idaho National Laboratory (INL) is producing enriched 134Ba isotopes that are tobe used for IDMS spikes to accurately determinemore » 137Ba accumulation from the decay of 137Cs. The final objective of this work it to provide a homogenous set of reference materials that the National Institute of Standards and Technology can certify as standard reference materials used for IDMS. The process that was developed at INL for the separation and isolation of Ba isotopes, chemical purification of the isotopes in solution, and the encapsulation of the materials will be described.« less

Biomonitoring of 30 trace elements in urine of children and adults by ICP-MS.

PubMed

Heitland, Peter; Köster, Helmut D

2006-03-01

The paper provides physicians and clinical chemists with statistical data (concentration ranges, geometric mean values, selected percentiles, etc.) about 30 urinary trace elements in order to determine whether people have trace element deficiencies or have been exposed to higher elemental concentrations. Morning urine samples of 72 children and 87 adults from two geographical areas of Germany were collected and the elements Li, Be, V, Cr, Mn, Ni, Co, Cu, Zn, Ga, As, Se, Rb, Sr, Mo, Rh, Pd, Ag, Cd, In, Sn, Sb, Cs, Ba, Pt, Au, Pb, Tl, Bi and U were determined by inductively coupled plasma mass spectrometry (ICP-MS) with a new octopole based collision/reaction cell. The urine samples were analysed directly after a simple 1/5 (V/V) dilution with deionised water and nitric acid. Information on exposure conditions of all human subjects were collected by questionnaire-based interviews. The described concentration data down to the ng/l range are very useful for the formulation of reference values. For some elements either new data are described (e.g., for V, Ga, In, Bi, Rh, Mn) or differences to earlier studies were found (e.g., for Be, As). For other elements (e.g., Sb, Se, Mo, Ba, Cu, Zn, Li) our results are in good correlation with previous studies and also complemented with urinary trace element concentrations for children.

Precise Measurements of the Masses of Cs, Rb and Na A New Route to the Fine Structure Constant

NASA Astrophysics Data System (ADS)

Rainville, Simon; Bradley, Michael P.; Porto, James V.; Thompson, James K.; Pritchard, David E.

2001-01-01

We report new values for the atomic masses of the alkali 133Cs, 87Rb, 85Rb, and 23Na with uncertainties ≤ 0.2 ppb. These results, obtained using Penning trap single ion mass spectrometry, are typically two orders of magnitude more accurate than previously measured values. Combined with values of h/m atom from atom interferometry measurements and accurate wavelength measurements for different atoms, these values will lead to new ppb-level determinations of the molar Planck constant N A h and the fine structure constant α. This route to α is based on simple physics. It can potentially achieve the several ppb level of accuracy needed to test the QED determination of α extracted from measurements of the electron g factor. We also demonstrate an electronic cooling technique that cools our detector and ion below the 4 K ambient temperature. This technique improves by about a factor of three our ability to measure the ion's axial motion.

Affinity capillary electrophoresis and density functional theory study of noncovalent interactions of cyclic peptide [Gly6 ]-antamanide with small cations.

PubMed

Pangavhane, Sachin; Böhm, Stanislav; Makrlík, Emanuel; Ruzza, Paolo; Kašička, Václav

2017-08-01

ACE and density functional theory were employed to study the noncovalent interactions of cyclic decapeptide glycine-6-antamanide ([Gly 6 ]AA), synthetic derivative of native antamanide (AA) peptide from the deadly poisonous fungus Amanita phalloides, with small cations (Li + , Rb + , Cs + , NH 4 + , and Ca 2+ ) in methanol. The strength of these interactions was quantified by the apparent stability constants of the appropriate complexes determined by ACE. The stability constants were calculated using the nonlinear regression analysis of the dependence of the effective electrophoretic mobility of [Gly 6 ]AA on the concentration of the above ions in the BGE (methanolic solution of 20 mM chloroacetic acid, 10 mM Tris, pH MeOH 7.8, containing 0-70 mM concentrations of the above ions added in the form of chlorides). Prior to stability constant calculation, the effective mobilities measured at actual temperature inside the capillary and at variable ionic strength of the BGEs were corrected to the values corresponding to the reference temperature of 25°C and to the constant ionic strength of 10 mM. From the above ions, Rb + and Cs + cations interacted weakly with [Gly 6 ]AA but no interactions of [Gly 6 ]AA with univalent Li + and NH 4 + ions and divalent Ca 2+ ion were observed. The apparent stability constants of [Gly 6 ]AA-Rb + and [Gly 6 ]AA-Cs + complexes were found to be equal to 13 ± 4 and 22 ± 3 L/mol, respectively. The structural characteristics of these complexes, such as position of the Rb + and Cs + ions in the cavity of the [Gly 6 ]AA molecule and the interatomic distances within these complexes, were obtained by the density functional theory calculations. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Cation-Dependent Gold Recovery with α-Cyclodextrin Facilitated by Second-Sphere Coordination.

PubMed

Liu, Zhichang; Samanta, Avik; Lei, Juying; Sun, Junling; Wang, Yuping; Stoddart, J Fraser

2016-09-14

Herein, we report an alkali metal cation-dependent approach to gold recovery, facilitated by second-sphere coordination with eco-friendly α-cyclodextrin (α-CD). Upon mixing eight salts composed of Na(+), K(+), Rb(+), or Cs(+) cations and [AuX4](-) (X = Cl/Br) anions with α-, β-, or γ-CD in water, co-precipitates form selectively from the three (out of 24) aqueous solutions containing α-CD with KAuBr4, RbAuBr4, and CsAuBr4, from which the combination of α-CD and KAuBr4 affords the highest yield. Single-crystal X-ray analyses reveal that in 20 of the 24 adducts CD and [AuX4](-) anions form 2:1 sandwich-type second-sphere adducts driven partially by [C-H···X-Au] interactions between [AuX4](-) anions and the primary faces of two neighboring CDs. In the adduct formed between α-CD and KAuBr4, a [K(OH2)6](+) cation is encapsulated inside the cavity between the secondary faces of two α-CDs, leading to highly efficient precipitation owing to the formation of a cation/anion alternating ion wire residing inside a continuous α-CD nanotube. By contrast, in the other 19 adducts, the cations are coordinated by OH groups and glucopyranosyl ring O atoms in CDs. The strong coordination of Rb(+) and Cs(+) cations by these ligands, in conjunction with the stereoelectronically favorable binding of [AuBr4](-) anions with two α-CDs, facilitates the co-precipitation of the two adducts formed between α-CD with RbAuBr4 and CsAuBr4. In order to develop an efficient process for green gold recovery, the co-precipitation yield of α-CD and KAuBr4 has been optimized regarding both the temperature and the molar ratio of α-CD to KAuBr4.

Trace element geochemistry (Li, Ba, Sr, and Rb) using Curiosity's ChemCam: early results for Gale crater from Bradbury Landing Site to Rocknest

USGS Publications Warehouse

Ollila, Ann M.; Newsom, Horton E.; Clark, Benton; Wiens, Roger C.; Cousin, Agnes; Blank, Jen G.; Mangold, Nicolas; Sautter, Violaine; Maurice, Sylvestre; Clegg, Samuel M.; Gasnault, Olivier; Forni, Olivier; Tokar, Robert; Lewin, Eric; Dyar, M. Darby; Lasue, Jeremie; Anderson, Ryan; McLennan, Scott M.; Bridges, John; Vaniman, Dave; Lanza, Nina; Fabre, Cecile; Melikechi, Noureddine; Perett, Glynis M.; Campbell, John L.; King, Penelope L.; Barraclough, Bruce; Delapp, Dorothea; Johnstone, Stephen; Meslin, Pierre-Yves; Rosen-Gooding, Anya; Williams, Josh

2014-01-01

The ChemCam instrument package on the Mars rover, Curiosity, provides new capabilities to probe the abundances of certain trace elements in the rocks and soils on Mars using the laser-induced breakdown spectroscopy technique. We focus on detecting and quantifying Li, Ba, Rb, and Sr in targets analyzed during the first 100 sols, from Bradbury Landing Site to Rocknest. Univariate peak area models and multivariate partial least squares models are presented. Li, detected for the first time directly on Mars, is generally low (100 ppm and >1000 ppm, respectively. These analysis locations tend to have high Si and alkali abundances, consistent with a feldspar composition. Together, these trace element observations provide possible evidence of magma differentiation and aqueous alteration.

High temperature redox reactions with uranium: Synthesis and characterization of Cs(UO{sub 2})Cl(SeO{sub 3}), Rb{sub 2}(UO{sub 2}){sub 3}O{sub 2}(SeO{sub 3}){sub 2}, and RbNa{sub 5}U{sub 2}(SO{sub 4}){sub 7}

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

Babo, Jean-Marie; Department of Civil and Environmental Engineering and Earth Sciences and Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556; Albrecht-Schmitt, Thomas E., E-mail: talbrechtschmitt@gmail.com

2013-10-15

Cs(UO{sub 2})Cl(SeO{sub 3}) (1), Rb{sub 2}(UO{sub 2}){sub 3}O{sub 2}(SeO{sub 3}){sub 3} (2), and RbNa{sub 5}U{sub 2}(SO{sub 4}){sub 7} (3) single crystals were synthesized using CsCl, RbCl, and a CuCl/NaCl eutectic mixture as fluxes, respectively. Their lattice parameters and space groups are as follows: P2{sub 1}/n (a=6.548(1) Å, b=11.052(2) Å, c=10.666(2) Å and β=93.897(3)°), P1{sup ¯} (a=7.051(2) Å, b=7.198(2) Å, c=8.314(2) Å, α=107.897(3)°, β=102.687(3)° and γ=100.564(3)°) and C2/c (a=17.862(4) Å, b=6.931(1) Å, c=20.133(4) Å and β=109.737(6)°. The small anionic building units found in these compounds are SeO{sub 3}{sup 2−} and SO{sub 4}{sup 2−} tetrahedra, oxide, and chloride. The crystal structure ofmore » the first compound is composed of [(UO{sub 2}){sub 2}Cl{sub 2}(SeO{sub 3}){sub 2}]{sup 2−} chains separated by Cs{sup +} cations. The structure of (2) is constructed from [(UO{sub 2}){sub 3}O{sub 11}]{sup 16−} chains further connected through selenite units into layers stacked perpendicularly to the [0 1 0] direction, with Rb{sup +} cations intercalating between them. The structure of compound (3) is made of uranyl sulfate layers formed by edge and vertex connections between dimeric [U{sub 2}O{sub 16}] and [SO{sub 4}] polyhedra. These layers contain unusual sulfate–metal connectivity as well as large voids. - Graphical abstract: A new family of uranyl selenites and sulfates has been prepared by high-temperature redox reactions. This compounds display new bonding motifs. Display Omitted - Highlights: • Low-dimensional Uranyl Oxoanion compounds. • Conversion of U(IV) to U(VI) at high temperatures. • Dimensional reduction by both halides and stereochemically active lone-pairs.« less

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

Linaburg, Matthew R.; McClure, Eric T.; Majher, Jackson D.

The structures of the lead halide perovskites CsPbCl3 and CsPbBr3 have been determined from X-ray powder diffraction data to be orthorhombic with Pnma space group symmetry. Their structures are distorted from the cubic structure of their hybrid analogs, CH3NH3PbX3 (X = Cl, Br), by tilts of the octahedra (Glazer tilt system a–b+a–). Substitution of the smaller Rb+ for Cs+ increases the octahedral tilting distortion and eventually destabilizes the perovskite structure altogether. To understand this behavior, bond valence parameters appropriate for use in chloride and bromide perovskites have been determined for Cs+, Rb+, and Pb2+. As the tolerance factor decreases, themore » band gap increases, by 0.15 eV in Cs1–xRbxPbCl3 and 0.20 eV in Cs1–xRbxPbBr3, upon going from x = 0 to x = 0.6. The band gap shows a linear dependence on tolerance factor, particularly for the Cs1–xRbxPbBr3 system. Comparison with the cubic perovskites CH3NH3PbCl3 and CH3NH3PbBr3 shows that the band gaps of the methylammonium perovskites are anomalously large for APbX3 perovskites with a cubic structure. This comparison suggests that the local symmetry of CH3NH3PbCl3 and CH3NH3PbBr3 deviate significantly from the cubic symmetry of the average structure.« less

Ferromagnetic Peierls insulator state in A Mg4Mn6O15(A =K ,Rb ,Cs )

NASA Astrophysics Data System (ADS)

Yamaguchi, T.; Sugimoto, K.; Ohta, Y.; Tanaka, Y.; Sato, H.

2018-04-01

Using the density-functional-theory-based electronic structure calculations, we study the electronic state of recently discovered mixed-valent manganese oxides A Mg4Mn6O15(A =K ,Rb ,Cs ) , which are fully spin-polarized ferromagnetic insulators with a cubic crystal structure. We show that the system may be described as a three-dimensional arrangement of the one-dimensional chains of a 2 p orbital of O and a 3 d orbital of Mn running along the three axes of the cubic lattice. We thereby argue that in the ground state the chains are fully spin polarized due to the double-exchange mechanism and are distorted by the Peierls mechanism to make the system insulating.

Optical properties from time-dependent current-density-functional theory: the case of the alkali metals Na, K, Rb, and Cs

NASA Astrophysics Data System (ADS)

Ferradás, R.; Berger, J. A.; Romaniello, Pina

2018-06-01

We present the optical conductivity as well as the electron-energy loss spectra of the alkali metals Na, K, Rb, and Cs calculated within time-dependent current-density functional theory. Our ab initio formulation describes from first principles both the Drude-tail and the interband absorption of these metals as well as the most dominant relativistic effects. We show that by using a recently derived current functional [Berger, Phys. Rev. Lett. 115, 137402 (2015)] we obtain an overall good agreement with experiment at a computational cost that is equivalent to the random-phase approximation. We also highlight the importance of the choice of the exchange-correlation potential of the ground state.

Matrix-isolation and comparative far-IR investigation of free linear [Cl3]- and a series of alkali trichlorides.

PubMed

Redeker, F A; Beckers, H; Riedel, S

2017-11-30

Here we discuss the reaction products of laser ablated alkali chlorides and elemental chlorine. Salt ablation using this technique combined with matrix-isolation spectroscopy allows for the formation and characterization of novel anionic species. The laser ablation of solid MCl with M = Cs, Rb, and K in the presence of Cl 2 produced free [Cl 3 ] - ions which were isolated in solid noble-gas matrices. For M = Cs, Rb, K, and Na, the ion pairs M + [Cl 3 ] - are the main reaction products. Trends in the formation and bonding of these trichloride anions will be discussed. In contrast to the trifluoride analogues, the isolated ion pairs M + [Cl 3 ] - feature a systematic distortion due to metal coordination.

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

Schafer, Marion; Bobev, Svilen

This paper presents results from our exploratory work in the systems K-Cd-Ge, Rb-Cd-Ge, and Cs-Cd-Ge, which yielded the novel type-I clathrates with refined compositions K 8Cd 3.77(7)Ge 42.23, Rb 8Cd 3.65(7)Ge 42.35, and Cs 7.80(1)Cd 3.65(6)Ge 42.35. The three compounds represent rare examples of clathrates of germanium with the alkali metals, where a d 10 element substitutes a group 14 element. The three structures, established by single-crystal X-ray diffraction, indicate that the framework-building Ge atoms are randomly substituted by Cd atoms on only one of the three possible crystallographic sites. Furthermore, this and several other details of the crystal chemistrymore » are elaborated.« less

Strain-Driven Approach to Quantum Criticality in AFe 2As 2 with A=K, Rb, and Cs

DOE PAGES

Eilers, Felix; Grube, Kai; Zocco, Diego A.; ...

2016-06-08

The iron-based superconductors AFe 2As 2 with A = K, Rb, Cs exhibit large Sommerfeld coefficients approaching those of heavy-fermion systems. We have investigated the magnetostriction and thermal expansion of this series to shed light on this unusual behavior. Quantum oscillations of the magnetostriction allow identifying the band-specific quasiparticle masses which by far exceed the band-structure derived masses. The divergence of the Grüneisen ratio derived from thermal expansion indicates that with increasing volume along the series a quantum critical point is approached. In conclusion, the critical fluctuations responsible for the enhancement of the quasiparticle masses appear to weaken the superconductingmore » state.« less

Variation of rock-forming metals in sub-annual increments of modern Greenland snow

USGS Publications Warehouse

Hinkley, T.K.

1992-01-01

Modern snowpack from central south Greenland was sampled in sub-seasonal increments and analysed for a suite of major, minor and trace rock-forming metals (K, Rb, Cs, Ca, Sr, Ba). There is a sharp seasonal concentration maximum for all six metals that comes in summer, later than mid-June. Metal concentrations in all other parts of the year's snowpack are up to 10 or more times smaller. The concentration maximum is preceded by low values in autumn-winter, very low values in early-mid-spring, and moderate-to-high values in late spring early summer; this pattern is seen consistently in three separate time stratigraphic intervals representing the same seasonal periods, spanning the time interval 1981-1984. The absolute concentration values of the snow strata representing the low-concentration portion of the year, autumn-winter-spring, may vary substantially from year to year, by a factor of two, or more. The finding that all rock-forming metals are at a sharp concentration maximum in late summer contrasts with the interpretations of several other studies in high-latitude northern regions. Those studies have reported a broad maximum of continental dust-associated metals in late winter and spring. However samples of the other studies have mostly come from regions farther to the north, and the analyses have emphasized industrial pollutant metals rather than the matched rock-forming suite of the present study. The metals measured were chosen to give information about the origin and identity of the rock and soil dusts, and sea salts, present as impurities in the snow. Metal ratios indicate that the dusts in the snowpacks are of continental origin and from ferromagnesian rocks. Source rock types for dusts in central south Greenland snow contrast with the felsic rock dusts of the Sierra Nevada, CA, annual snowpacks, and with the very felsic rock dusts in large south central Alaskan mountain glaciers. Samples in which masses of sea salt are much larger than those of rock dusts may be identified by small changes in metal ratios caused by moderate increases of K and Ca from marine sources, nearly unaccompanied by the minor and trace metals Rb, Cs and Ba, that are very rare in the oceans. A sampling frequency, such as that of the present study, that divides a year's accumulation into 8-10 subsamples is sufficient to reveal details of the time pattern of variation in proportions and concentrations of metals that give information about atmospheric deposition of important types of earth materials.Modern snowpack from central south Greenland was sampled in sub-seasonal increments and analyzed for a suite of major, minor and trace rock-forming metals (K, Rb, Cs, Ca, Sr, Ba). There is a sharp seasonal concentration maximum for all six metals that comes in summer, later than mid-June. Metal concentrations in all other parts of the year's snowpack are up to 10 or more times smaller. The concentration maximum is preceded by low values in autumn-winter, very low values in early-mid-spring, and moderate-to-high values in late spring-early summer; this pattern is seen consistently in three separate time stratigraphic intervals representing the same seasonal periods, spanning the time interval 1981-1984. The absolute concentration values of the snow strata representing the low-concentration portion of the year, autumn-winter-spring, may vary substantially from year to year, by a factor of two, or more. The finding that all rock-forming metals are at a sharp concentration maximum in late summer contrasts with the interpretations of several other studies in high-latitude northern regions. Those studies have reported a broad maximum of continental dust-associated metals in late winter and spring. However, samples of the other studies have mostly come from regions farther to the north, and the analyses have emphasized industrial pollutant metals rather than the matched rock-forming suite of the present study. The metals measured were chosen to give informati

Cooling of trapped ions by resonant charge exchange

NASA Astrophysics Data System (ADS)

Dutta, Sourav; Rangwala, S. A.

2018-04-01

The two most widely used ion cooling methods are laser cooling and sympathetic cooling by elastic collisions (ECs). Here, we demonstrate another method of cooling ions that is based on resonant charge exchange (RCE) between the trapped ion and the ultracold parent atom. Specifically, trapped C s+ ions are cooled by collisions with cotrapped, ultracold Cs atoms and, separately, by collisions with cotrapped, ultracold Rb atoms. We observe that the cooling of C s+ ions by Cs atoms is more efficient than the cooling of C s+ ions by Rb atoms. This signals the presence of a cooling mechanism apart from the elastic ion-atom collision channel for the Cs-C s+ case, which is cooling by RCE. The efficiency of cooling by RCE is experimentally determined and the per-collision cooling is found to be two orders of magnitude higher than cooling by EC. The result provides the experimental basis for future studies on charge transport by electron hopping in atom-ion hybrid systems.

Rb-Sr Isotopic Systematics of Alkali-Rich Fragments in the Yamato-74442 LL-Chondritic Breccia

NASA Technical Reports Server (NTRS)

Yokoyama, T.; Misawa, K.; Okano, O.; Shih, C.-Y.; Nyquist, L. E.; Simo, J. I.; Tappa, M. J.; Yoneda, S.

2012-01-01

Alkali-rich igneous fragments were identified in the brecciated LL-chondrites, Kr henberg (LL5)], Bhola (LL3-6) and Yamato (Y)-74442 (LL4), and show characteristic fractionation patterns of alkaline elements. The K-Rb-Cs-rich fragments in Kr henberg, Bhola, and Y-74442 are very similar in mineralogy and petrography (olivine + pyroxene + glass), suggesting that they could have come from related precursor materials. We have undertaken Rb-Sr isotopic studies on alkali-rich fragments in Y-74442 to precisely determine their crystallization ages and the isotopic signatures of their precursor material(s).

Synthesis and characterization of new fluoride-containing manganese vanadates A{sub 2}Mn{sub 2}V{sub 2}O{sub 7}F{sub 2} (A=Rb, Cs) and Mn{sub 2}VO{sub 4}F

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

Sanjeewa, Liurukara D.; McGuire, Michael A.; Smith Pellizzeri, Tiffany M.

2016-09-15

Large single crystals of A{sub 2}Mn{sub 2}V{sub 2}O{sub 7}F{sub 2} (A=Rb, Cs) and Mn{sub 2}VO{sub 4}F were grown using a high-temperature (~600 °C) hydrothermal technique. Single crystal X-ray diffraction and powder X-ray diffraction were utilized to characterize the structures, which both possess MnO{sub 4}F{sub 2} building blocks. The A{sub 2}Mn{sub 2}V{sub 2}O{sub 7}F{sub 2} series crystallizes as a new structure type in space group Pbcn (No. 60), Z=4 (Rb{sub 2}Mn{sub 2}V{sub 2}O{sub 7}F{sub 2}: a=7.4389(17) Å, b=11.574(3) Å, c=10.914(2) Å; Cs{sub 2}Mn{sub 2}V{sub 2}O{sub 7}F{sub 2}: a=7.5615(15) Å, b=11.745(2) Å, c=11.127(2) Å). The structure is composed of zigzag chains ofmore » edge-sharing MnO{sub 4}F{sub 2} units running along the a-axis, and interconnected through V{sub 2}O{sub 7} pyrovanadate groups. Temperature dependent magnetic susceptibility measurements on this interesting one-dimensional structural feature based on Mn{sup 2+} indicated that Cs{sub 2}Mn{sub 2}V{sub 2}O{sub 7}F{sub 2} is antiferromagnetic with a Neél temperature, T{sub N}=~3 K and a Weiss constant, θ, of −11.7(1) K. Raman and infrared spectra were also analyzed to identify the fundamental V–O vibrational modes in Cs{sub 2}Mn{sub 2}V{sub 2}O{sub 7}F{sub 2}. Mn{sub 2}(VO{sub 4})F crystalizes in the monoclinic space group of C2/c (no. 15), Z=8 with unit cell parameters of a=13.559(2) Å, b=6.8036(7) Å, c=10.1408(13) Å and β=116.16(3)°. The structure is associated with those of triplite and wagnerite. Dynamic fluorine disorder gives rise to complex alternating chains of five-and six-coordinate Mn{sup 2+}. These interpenetrating chains are additionally connected through isolated VO{sub 4} tetrahedra to form the condensed structure. - Graphical abstract: New vanadate fluorides A{sub 2}Mn{sub 2}V{sub 2}O{sub 7}F{sub 2} (A=Rb, Cs) and Mn{sub 2}(VO{sub 4})F have been synthesized hydrothermally. Upon cooling, the one-dimensional Mn(II) substructure results in antiferromagnetic ordering. Display Omitted - Highlights: • Single crystals of A{sub 2}Mn{sub 2}V{sub 2}O{sub 7}F{sub 2}, (A=Rb, Cs) and Mn{sub 2}VO{sub 4}F were grown hydrothermally. • The use of fluoride mineralizers in the synthesis led to the formation of new compounds without OH{sup −} groups. • The structure of A{sub 2}Mn{sub 2}V{sub 2}O{sub 7}F{sub 2} features zigzag chains of MnO{sub 4}F{sub 2} units. • Cs{sub 2}Mn{sub 2}V{sub 2}O{sub 7}F{sub 2} exhibits antiferromagnetic ordering with a Neel temperature of ~3 K. • Mn{sub 2}VO{sub 4}F possesses a condensed framework structure with disordered fluorine atoms.« less

Crown Ether Complexes of Alkali-Metal Chlorides from SO2.

PubMed

Reuter, Kirsten; Rudel, Stefan S; Buchner, Magnus R; Kraus, Florian; von Hänisch, Carsten

2017-07-18

The structures of alkali-metal chloride SO 2 solvates (Li-Cs) in conjunction with 12-crown-4 or 1,2-disila-12-crown-4 show strong discrepancies, despite the structural similarity of the ligands. Both types of crown ethers form 1:1 complexes with LiCl to give [Li(1,2-disila-12-crown-4)(SO 2 Cl)] (1) and [Li(12-crown-4)Cl]⋅4 SO 2 (2). However, 1,2-disila-12-crown-4 proved unable to coordinate cations too large for the cavity diameter, for example, by the formation of sandwich-type complexes. As a result, 12-crown-4 reacts exclusively with the heavier alkali-metal chlorides NaCl, KCl and RbCl. Compounds [Na(12-crown-4) 2 ]Cl⋅4 SO 2 (3) and [M(12-crown-4) 2 (SO 2 )]Cl⋅4 SO 2 (4: M=K; 5: M=Rb) all showed S-coordination to the chloride ions through four SO 2 molecules. Compounds 4 and 5 additionally exhibit the first crystallographically confirmed non-bridging O,O'-coordination mode of SO 2 . Unexpectedly, the disila-crown ether supports the dissolution of RbCl and CsCl in the solvent and gives the homoleptic SO 2 -solvated alkali-metal chlorides [MCl⋅3 SO 2 ] (6: M=Rb; 7: M=Cs), which incorporate bridging μ-O,O'-coordinating moieties and the unprecedented side-on O,O'-coordination mode. All compounds were characterised by single-crystal X-ray diffraction. The crown ether complexes were additionally studied by using NMR spectroscopy, and the presence of SO 2 at ambient temperature was revealed by IR spectroscopy of the neat compounds. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Crystal structure of the new A2SnTa6X18 (A = K, Rb, Cs; X = Cl, Br) cluster compounds

NASA Astrophysics Data System (ADS)

Lemoine, P.; Wilmet, M.; Malaman, B.; Paofai, S.; Dumait, N.; Cordier, S.

2018-01-01

The crystal structure of the new cluster compounds A2SnTa6X18 (with A = K, Rb, Cs, and X = Cl, Br) was determined by using single-crystal and powder X-ray diffraction, and 119Sn Mössbauer spectroscopy. Those compounds crystallize in the Cs2EuNb6Br18-type structure of space group R 3 ̅. This type of structure is built up on discrete edge-bridged [M6Xi12Xa6]4- cluster units arranged according to a pseudo face-centered cubic stacking, where the octahedral and tetrahedral vacancies are fully occupied by divalent tin cations and monovalent alkaline cations, respectively. The tin cations influence on the halogen matrix and the electronic effects on the cluster units in the Cs2EuNb6Br18-type structure are discussed by comparison with isotype compounds. From those analyses, the ionic radius of Sn2+ in coordination number VI is estimated to be 1.14(1) Å. Finally, K2SnTa6Br18 might be considered as a new example of compound containing a quite bare stannous ion (5 s2 configuration).

Provenance of fine-grained sediments in the inner shelf of the Korea Strait (South Sea), Korea

NASA Astrophysics Data System (ADS)

Um, In kwon; Choi, Man Sik; Bae, Sung Ho; Song, Yunho; Kong, Gee Soo

2017-12-01

Major metals (Al, Fe, Mg, and Ti), trace metals (Li, Cs, Sc, and Rb), and rare earth elements (REEs) in the fine-grained sediments (< 15 μm) of the central South Sea mud (CSSM) were analyzed to determine the sediment provenance. The spatial distribution of the analyzed elements showed a clear separation between the western (W-CSSM) and eastern (E-CSSM) regions of the CSSM. Concentrations of Fe, Ti, Mg, Sc, and REEs were higher in the WCSSM, whereas concentrations of Al, Cs, Li, and Rb were higher in the E-CSSM. Unlike the ratios of trace metals ((Cs+Sc)/Li and Rb/Li), REEs could not be used to track the provenance of fine-grained sediments because of a grain size effect. The mixing relationships of the provenance indicators showed that the fine-grained sediments of the CSSM comprise a mixture of the sediments discharged from the Seomjin River (SRS) and sediments eroded and transported from the Heuksan mud belt (HMBS) area by the Korean Coastal Current. Sediments originating from the HMB were deposited mostly in the W-CSSM, whereas those from the Seomjin River were deposited mostly in the E-CSSM. This study indicated that sediments from Chinese rivers as well as the Geum River are important even in the inner shelf of the South Sea of Korea.

Provenance of Fine-grained Sediments in the Inner Shelf of the Korea Strait (South Sea), Korea

NASA Astrophysics Data System (ADS)

Um, In kwon; Choi, Man Sik; Bae, Sung Ho; Song, Yunho; Kong, Gee Soo

2018-03-01

Major metals (Al, Fe, Mg, and Ti), trace metals (Li, Cs, Sc, and Rb), and rare earth elements (REEs) in the fine-grained sediments (< 15 μm) of the central South Sea mud (CSSM) were analyzed to determine the sediment provenance. The spatial distribution of the analyzed elements showed a clear separation between the western (W-CSSM) and eastern (E-CSSM) regions of the CSSM. Concentrations of Fe, Ti, Mg, Sc, and REEs were higher in the WCSSM, whereas concentrations of Al, Cs, Li, and Rb were higher in the E-CSSM. Unlike the ratios of trace metals ((Cs+Sc)/Li and Rb/Li), REEs could not be used to track the provenance of fine-grained sediments because of a grain size effect. The mixing relationships of the provenance indicators showed that the fine-grained sediments of the CSSM comprise a mixture of the sediments discharged from the Seomjin River (SRS) and sediments eroded and transported from the Heuksan mud belt (HMBS) area by the Korean Coastal Current. Sediments originating from the HMB were deposited mostly in the W-CSSM, whereas those from the Seomjin River were deposited mostly in the E-CSSM. This study indicated that sediments from Chinese rivers as well as the Geum River are important even in the inner shelf of the South Sea of Korea.

Jahn-Teller distortion of Mn3+-occupied octahedra in red beryl from Utah indicated by optical spectroscopy

NASA Astrophysics Data System (ADS)

Fridrichová, Jana; Bačík, Peter; Ertl, Andreas; Wildner, Manfred; Dekan, Július; Miglierini, Marcel

2018-01-01

Red beryl from Utah is chemically homogeneous and contains only Fe < 0.163, Mn < 0.018, and Mg < 0.016 apfu. Channel sites contain only up to Cs 0.011, K 0.009, Rb 0.004, and Na 0.004 apfu. This suggests only very slight tetrahedral (Cs,K,Rb)Li□-1Be-1 substitution, octahedral Na(Fe2+,Mg)□-1Al-1 substitution can be excluded. Fe and Mn are trivalent as documented by Mössbauer spectroscopy and optical absorption spectroscopy. Red beryl optimized formula is ∼[(Cs,Rb,K)0.02□0.98]Σ1.00□1.00(Al1.79Fe3+0.16Mn3+0.02Ti4+0.02Mg0.01)Σ2.00Be3(Si6O18). Location of Mn3+ was estimated to the octahedral Al3+ site, other choices are improbable due to the bond-length requirements. No Mn3+-induced Jahn-Teller structural distortion was detected due to site symmetry restrictions and small Mn3+ content. However, optical spectroscopy shows broad band at ∼7190 cm-1 assigned to the excited level of the spin-allowed pseudo-tetragonal split E ground state of elongated six-fold Mn3+ coordination. Crystal field calculations indicate that the local Mn3+ environment complies well with crystal chemical expectations for Jahn-Teller distorted Mn3+O6 octahedra.

Geochemical aspects of some Japanese lavas.

NASA Technical Reports Server (NTRS)

Philpotts, J. A.; Martin, W.; Schnetzler, C. C.

1971-01-01

K, Rb, Sr, Ba and rare-earth concentrations in some Japanese lavas have been determined by mass-spectrometric stable-isotope dilution. The samples fall into three rare-earth groups corresponding to tholeiitic, high alumina and alkali basalts. Japanese tholeiites have trace element characteristics similar to those of oceanic ridge tholeiites except for distinctly higher relative concentrations of Ba. Japanese lavas may result from various degrees of partial fusion of amphibole eclogite.

A strategy for optical properties investigation in ABe2BO3F2 (A=K, Rb, Cs) using finite field methods

NASA Astrophysics Data System (ADS)

Mushahali, Hahaer; Mu, Baoxia; Wang, Qian; Mamat, Mamatrishat; Cao, Haibin; Yang, Guang; Jing, Qun

2018-07-01

The finite-field methods can be used to intuitively learn about the optical response and find out the atomic contributions to the birefringence and SHG tensors. In this paper, the linear and second-order nonlinear optical properties of ABe2BO3F2 family (A = K, Rb, Cs) compounds are investigated using the finite-field methods within different exchange-correlation functionals. The results show that the obtained birefringence and SHG tensors are in good agreement with the experimental values. The atomic contribution to the total birefringence was further investigated using the variation of the atomic charges, and the Born effective charges. The results show that the boron-oxygen groups give main contribution to the anisotropic birefringence.

Non-noble metal vanadium phosphites with broad absorption for photocatalytic hydrogen evolution

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

Song, Jun-Ling, E-mail: s070054@e.ntu.edu.sg; State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002; Zhang, Jian-Han

2016-05-15

We reported the synthesis and crystal structures of alkali metal and alkali-earth metal phosphite, namely, CsV{sub 2}(H{sub 3}O)(HPO{sub 3}){sub 4} (1), and Ba{sub 3}V{sub 2}(HPO{sub 3}){sub 6} (2). Both compounds were prepared by hydrothermal reactions and feature unique new structures. They both exhibit 3D complicated frameworks based on VO{sub 6} octahedra which are connected by HPO{sub 3} tetrahedra via corner-sharing. Alkali or alkali earth metal cations are filled in the different channels of the frameworks. Topological analysis shows that the framework of CsV{sub 2}(H{sub 3}O) (HPO{sub 3}){sub 4} (1) is a new 3,3,3,4,5-connected network with the Schläfli symbol of {4.6"2}{submore » 2}{4"2.6"6.8"2}{6"3}{6"5.8}. The investigations of X-ray photoelectron spectroscopy (XPS) and magnetic measurement on CsV{sub 2}(H{sub 3}O)(HPO{sub 3}){sub 4} suggest a +3 oxidation state of the vanadium ions in compound 1. Photocatalytic performance was evaluated by photocatalytic H{sub 2} evolution and degradation of methylene blue, which shows that both compounds exhibit activity under visible-light irradiation. IR spectrum, UV–vis-NIR spectrum and thermogravimetric analysis (TGA) of compounds were also investigated. - Graphical abstract: Metal vanadium phosphites with broad absorption for photocatalytic hydrogen evolution and the degradation of methylene blue aqueous solution. - Highlights: • Two new vanadium phosphites, CsV{sub 2}(H{sub 3}O)(HPO{sub 3}){sub 4} and Ba{sub 3}V{sub 2}(HPO{sub 3}){sub 6}, are reported. • CsV{sub 2}(H{sub 3}O)(HPO{sub 3}){sub 4} and Ba{sub 3}V{sub 2}(HPO{sub 3}){sub 6} feature complicated 3D framework structures with different channels. • CsV{sub 2}(H{sub 3}O)(HPO{sub 3}){sub 4} and Ba{sub 3}V{sub 2}(HPO{sub 3}){sub 6} exhibit strong and broad absorptions in the visible and Near IR region. • Photocatalytic properties of CsV{sub 2}(H{sub 3}O)(HPO{sub 3}){sub 4} and Ba{sub 3}V{sub 2}(HPO{sub 3}){sub 6} are investigated. • The magnetic measurement of CsV{sub 2}(H{sub 3}O)(HPO{sub 3}){sub 4} was performed in the temperature range of 2–300 K.« less

Two superconducting transitions in single-crystal La 2 - x Ba x CuO 4

DOE PAGES

Tee, X. Y.; Ito, T.; Ushiyama, T.; ...

2017-02-27

Here, we use spatially-resolved transport techniques to investigate the superconducting properties of single crystals La 2-xBa xCuO 4. We also found a superconducting transition temperature T cs associated with the ab-plane surface region which is considerably higher than the bulk T c. This effect is pronounced in the region of charge carrier doping x with strong spin-charge stripe correlations, reaching T cs = 36 K or 1.64T c.

Network Meta-Analysis Comparing the Efficacy of Therapeutic Treatments for Bronchiolitis in Children.

PubMed

Guo, Caili; Sun, Xiaomin; Wang, Xiaowen; Guo, Qing; Chen, Dan

2018-01-01

This study aims to compare placebo (PBO) and 7 therapeutic regimens-namely, bronchodilator agents (BAs), hypertonic saline (HS), BA ± HS, corticosteroids (CS), epinephrine (EP), EP ± CS, and EP ± HS-to determine the optimal bronchiolitis treatment. We plotted networks using the curative outcome of several studies and specified the relations among the experiments by using mean difference, standardized mean difference, and corresponding 95% credible interval. The surface under the cumulative ranking curve (SUCRA) was used to separately rank each therapy on clinical severity score (CSS) and length of hospital stay (LHS). This network meta-analysis included 40 articles from 1995 to 2016 concerning the treatment of bronchiolitis in children. All 7 therapeutic regimens displayed no significant difference to PBO with regard to CSS in our study. Among the 7 therapies, BA performed better than CS. As for LHS, EP and EP ± HS had an advantage over PBO. Moreover, EP and EP ± HS were also more efficient than BA. The SUCRA results showed that EP ± CS is most effective, and EP ± HS is second most effective with regard to CSS. With regard to LHS, EP ± HS ranked first, EP ± CS ranked second, and EP ranked third. We recommend EP ± CS and EP ± HS as the first choice for bronchiolitis treatment in children because of their outstanding performance with regard to CSS and LHS. © 2017 American Society for Parenteral and Enteral Nutrition.

Context-Dependent Encoding of Fear and Extinction Memories in a Large-Scale Network Model of the Basal Amygdala

PubMed Central

Vlachos, Ioannis; Herry, Cyril; Lüthi, Andreas; Aertsen, Ad; Kumar, Arvind

2011-01-01

The basal nucleus of the amygdala (BA) is involved in the formation of context-dependent conditioned fear and extinction memories. To understand the underlying neural mechanisms we developed a large-scale neuron network model of the BA, composed of excitatory and inhibitory leaky-integrate-and-fire neurons. Excitatory BA neurons received conditioned stimulus (CS)-related input from the adjacent lateral nucleus (LA) and contextual input from the hippocampus or medial prefrontal cortex (mPFC). We implemented a plasticity mechanism according to which CS and contextual synapses were potentiated if CS and contextual inputs temporally coincided on the afferents of the excitatory neurons. Our simulations revealed a differential recruitment of two distinct subpopulations of BA neurons during conditioning and extinction, mimicking the activation of experimentally observed cell populations. We propose that these two subgroups encode contextual specificity of fear and extinction memories, respectively. Mutual competition between them, mediated by feedback inhibition and driven by contextual inputs, regulates the activity in the central amygdala (CEA) thereby controlling amygdala output and fear behavior. The model makes multiple testable predictions that may advance our understanding of fear and extinction memories. PMID:21437238

LPTF frequency synthesis chain: Results and improvement for the near future

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

Touahri, D.; Zondy, J.J.; Acef, O.

1994-12-31

We have measured the frequency of the He-Ne/12 laser starting from the Cs referenced CO{sub 2}/OsO{sub 4} laboratory standard. As the laser diode stabilized on the two-photon transition in Rb seems to be a suitable reference for spectroscopic studies. (H, He ... ) and a promising standard, we are modifying our chain in order to measure frequencies around 780 nm and specially the Rb one.

Preparation of hair for measurement of elements by inductively coupled plasma-mass spectrometry (ICP-MS).

PubMed

Puchyr, R F; Bass, D A; Gajewski, R; Calvin, M; Marquardt, W; Urek, K; Druyan, M E; Quig, D

1998-06-01

The preparation of hair for the determination of elements is a critical component of the analysis procedure. Open-beaker, closed-vessel microwave, and flowthrough microwave digestion are methods that have been used for sample preparation and are discussed. A new digestion method for use with inductively coupled plasma-mass spectrometry (ICP-MS) has been developed. The method uses 0.2 g of hair and 3 mL of concentrated nitric acid in an atmospheric pressure-low-temperature microwave digestion (APLTMD) system. This preparation method is useful in handling a large numbers of samples per day and may be adapted to hair sample weights ranging from 0.08 to 0.3 g. After digestion, samples are analyzed by ICP-MS to determine the concentration of Li, Be, B, Na, Mg, Al, P, S, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ge, As, Se, Rb, Sr, Zr, Mo, Pd, Ag, Cd, Sn, Sb, I, Cs, Ba, Pt, Au, Hg, Tl, Pb, Bi, Th, and U. Benefits of the APLTMD include reduced contamination and sample handling, and increased precision, reliability, and sample throughput.

Chemical analyses of hot springs, pools, geysers, and surface waters from Yellowstone National Park, Wyoming, and vicinity, 1974-1975

USGS Publications Warehouse

Ball, James W.; Nordstrom, D. Kirk; Jenne, Everett A.; Vivit, Davison V.

1998-01-01

This report presents all analytical determinations for samples collected from Yellowstone National Park and vicinity during 1974 and 1975. Water temperature, pH, Eh, and dissolved O2 were determined on-site. Total alkalinity and F were determined on the day of sample collection. Flame atomic-absorption spectrometry was used to determine concentrations of Li, Na, K, Ca, and Mg. Ultraviolet/visible spectrophotometry was used to determine concentrations of Fe(II), Fe(III), As(III), and As(V). Direct-current plasma-optical-emission spectrometry was used to determine the concentrations of B, Ba, Cd, Cs, Cu, Mn, Ni, Pb, Rb, Sr, and Zn. Two samples collected from Yellowstone Park in June 1974 were used as reference samples for testing the plasma analytical method. Results of these tests demonstrate acceptable precision for all detectable elements. Charge imbalance calculations revealed a small number of samples that may have been subject to measurement errors in pH or alkalinity. These data represent some of the most complete analyses of Yellowstone waters available.

Behaviour of elements in soils developed from nephelinites at Mount Etinde (Cameroon): Impact of hydrothermal versus weathering processes

NASA Astrophysics Data System (ADS)

Etame, J.; Gerard, M.; Bilong, P.; Suh, C. E.

2009-05-01

The progressive weathering of 0.65 Ma nephelinites from Mount Etinde (South Western Cameroon) in a humid tropical setting has resulted in the formation of a 150 cm thick weathering crust. The soil profiles consist of three horizons: Ah/Bw/C. A major differentiation of the chemical and mineralogical parameters is related to the complexity of the saprolites, some of which were hydrothermally altered. Bulk geochemical and microgeochemical analyses were performed on selected minerals from the different horizons of two reference profiles, of which one (E 4) was developed from unaltered nephelinite (nephelinite U) while the other (BO 1) formed from hydrothermally altered nephelinite (nephelinite H). The results show that the primary minerals (clinopyroxene, nepheline, leucite, haüyne, titanomagnetite, perovskite, apatite and sphene) experienced differential weathering rates with primary minerals rich in rare earth elements (titanomagnetite, perovskite, apatite and sphene) surviving in the saprolite and the Bw horizons. The weathering of the primary minerals is reflected in the leaching of alkaline and alkaline-earth elements, except for Ba and Rb in the hydrothermalised nephelinite soil. The order of mobility is influenced by hydrothermal processes: Na > K > Rb > Ca > Cs > Sr in nephelinite U soil , Na > K > Sr > Ca > Mg in nephelinite H soil; Rb/Sr and Sr/Mg can be used as indicators of the kinetic of the weathering on nephelinite U and on nephelinite H. Barium enrichment is related to variable concentrations in the nephelinites, to the formation of crandallites and the leaching of surface horizons. The content of metallic elements is higher in nephelinite H soil than in the nephelinite U soil. Results show that hydrothermal alteration leads to an enrichment of light (La, Ce, Nd) and intermediate (Sm, Eu, Dy) rare earth elements. The enrichment in Cr and Pb in the surface horizons is discussed in relation to organic matter activity, the dissolution of magnetites, and the impact of hydrothermal processes as well as atmospheric pollution in the case of lead.

Variability of As and other fluid-mobile trace elements (FME) in Mariana forearc serpentinites and entrained crustal rocks

NASA Astrophysics Data System (ADS)

Johnston, R.; Ryan, J. G.

2017-12-01

In the Mariana subduction system, active serpentinite mud volcanoes are associated with the subduction of the Pacific plate beneath the Philippine Sea plate in a non-accretionary convergent plate margin. We are examining the systematics of As and other fluid-mobile trace elements (FME: Cs, Rb, Pb, B, Li) in serpentinized ultramafic clasts and serpentinite muds recovered during IODP Expedition 366 and previous ODP Legs (125, 195) to constrain the role of slab-derived fluids and the P-T° conditions at which fluids are mobilized. Arsenic concentrations in Exp. 366 serpentinites range from 0.08-2 ppm, while Cs varies from 0.001-0.9 ppm, Rb from 0.05-20 ppm and Pb varies from 0.02-10 ppm. The two different seamount summit sites examined (Yinazao: 55 km distance to trench; Asut Tesoru: 72 km to trench) (Hulme, 2010) show marked mobile element abundance differences, with Yinazao serpentinites showing lower As, Cs and Rb, and higher Pb contents than those from Asut Tesoru. Serpentinite mud samples from each seamount are on average higher in FME abundances than are associated serpentinized clasts, though their ranges overlap. Entrained mafic clasts are as high or higher in FME than the serpentinites, perhaps pointing to greater affinities for many of these elements during fluid-rock exchange. Asut Tesoru serpentinites are similar in As, Cs, and Rb abundances to those from S. Chamorro and Conical Seamounts (Savov et al 2005;2007), which also reflect greater distances to trench (78 and 86 km, respectively)(Hulme, 2010). The patterns of serpentinite FME abundances from seamount to seamount mimic to a great degree the dichotomy in cation abundances observed in their associated porefluids, where B and K are markedly lower, and Sr and Ca are markedly higher in Yinazao summit fluids than at the summits of Asut Tesoru, S. Chamorro, or Conical. These abrupt changes in serpentinite and fluid compositions likely reflect the initiation of carbonate and clay breakdown reactions on the downgoing plate in the earliest stages of subduction metamorphism.

Energy and radiative properties of the (3 )1Π and (5 )+1Σ states of RbCs: Experiment and theory

NASA Astrophysics Data System (ADS)

Alps, K.; Kruzins, A.; Nikolayeva, O.; Tamanis, M.; Ferber, R.; Pazyuk, E. A.; Stolyarov, A. V.

2017-08-01

We combined high-resolution Fourier-transform spectroscopy and large-scale electronic structure calculation to study energy and radiative properties of the high-lying (3 )1Π and (5 )+1Σ states of the RbCs molecule. The laser-induced (5 )+1Σ,(4 )+1Σ,(3 )1Π→A (2 )+1Σ˜ b (1 )3Π fluorescence (LIF) spectra were recorded by the Bruker IFS-125(HR) spectrometer in the frequency range ν ∈[5500 ,10 000 ] cm-1 with the instrumental resolution of 0.03 cm-1. The rotational assignment of the observed LIF progressions, which exhibit irregular vibrational-rotational spacing due to strong spin-orbit interaction between A +1Σ and b 3Π states was based on the coincidences between observed and calculated energy differences. The required rovibronic term values of the strongly perturbed A ˜b complex have been calculated by a coupled-channels approach for both 85Rb133Cs and 87Rb133Cs isotopologs with accuracy of about 0.01 cm-1, as demonstrated in A. Kruzins et al. [J. Chem. Phys. 141, 184309 (2014), 10.1063/1.4901327]. The experimental energies of the upper (3 )1Π and (5 )+1Σ states were involved in a direct-potential-fit analysis performed in the framework of inverted perturbation approach. Quasirelativistic ab initio calculations of the spin-allowed (3 )1Π,(5 )+1Σ→ (1-4)+1Σ,(1-3)1Π transition dipole moments were performed. Radiative lifetimes and vibronic branching ratios of radiative transitions from the (3 )1Π and (5 )+1Σ states were evaluated. To elucidate the origin of the Λ -doubling effect in the (3 )1Π state, the angular coupling (3 )1Π -(1-5)+1Σ electronic matrix elements were calculated and applied for the relevant q -factors estimate. The intensity distributions simulated for the particular (5 )+1Σ ;(3 )1Π→A ˜b LIF progressions have been found to be remarkably close to their experimental counterparts.

Hydrothermal syntheses, structures, and properties of the new uranyl selenites Ag(2)(UO(2))(SeO(3))(2), M[(UO(2))(HSeO(3))(SeO(3))] (M = K, Rb, Cs, Tl), and Pb(UO(2))(SeO(3))(2).

PubMed

Almond, Philip M; Albrecht-Schmitt, Thomas E

2002-03-11

The transition metal, alkali metal, and main group uranyl selenites, Ag(2)(UO(2))(SeO(3))(2) (1), K[(UO(2))(HSeO(3))(SeO(3))] (2), Rb[(UO(2))(HSeO(3))(SeO(3))] (3), Cs[(UO(2))(HSeO(3))(SeO(3))] (4), Tl[(UO(2))(HSeO(3))(SeO(3))] (5), and Pb(UO(2))(SeO(3))(2) (6), have been prepared from the hydrothermal reactions of AgNO(3), KCl, RbCl, CsCl, TlCl, or Pb(NO(3))(2) with UO(3) and SeO(2) at 180 degrees C for 3 d. The structures of 1-5 contain similar [(UO(2))(SeO(3))(2)](2-) sheets constructed from pentagonal bipyramidal UO(7) units that are joined by bridging SeO(3)(2-) anions. In 1, the selenite oxo ligands that are not utilized within the layers coordinate the Ag(+) cations to create a three-dimensional network structure. In 2-5, half of the selenite ligands are monoprotonated to yield a layer composition of [(UO(2))(HSeO(3))(SeO(3))](1-), and coordination of the K(+), Rb(+), Cs(+), and Tl(+) cations occurs through long ionic contacts. The structure of 6 contains a uranyl selenite layered substructure that differs substantially from those in 1-5 because the selenite anions adopt both bridging and chelating binding modes to the uranyl centers. Furthermore, the Pb(2+) cations form strong covalent bonds with these anions creating a three-dimensional framework. These cations occur as distorted square pyramidal PbO(5) units with stereochemically active lone pairs of electrons. These polyhedra align along the c-axis to create a polar structure. Second-harmonic generation (SHG) measurements revealed a response of 5x alpha-quartz for 6. The diffuse reflectance spectrum of 6 shows optical transitions at 330 and 440 nm. The trailing off of the 440 nm transition to longer wavelengths is responsible for the orange coloration of 6.

Mapping the Mariana Seismogenic Zone Through the Measurement of Geochemical Tracers in Serpentinite Seamounts

NASA Astrophysics Data System (ADS)

Hulme, S. M.; Wheat, C. G.; Mottl, M. J.; Fryer, P.

2003-12-01

The Mariana forearc contains tens of seamounts up to 2 km high and 20-50 km in diameter. These seamounts were formed by serpentinite mud volcanism, sometimes in combination with uplift of serpentinized forearc mantle blocks, in which fluids driven off of the subducting slab infiltrated the overlying mantle and serpentinized the harzburgite and dunite rocks creating a density imbalance within the mantle. The resulting fluid-rock matrix flows along faults and exposes mantle-sourced serpentinite muds, blueschist facies metamorphosed mafic clasts, and slab-sourced fluids at the seafloor. The protrusion of these materials allows direct observation of active subduction zone components that are elsewhere buried beneath kilometers of rock and sediment. A multi-disciplinary survey of the Mariana Forearc was conducted in the spring of 2003 to study the biogeochemical properties of this mud volcanism. Seven different seamounts were sampled using shipboard and subsea coring techniques employing RV Thomas G. Thompson and ROV Jason II, respectively. Pore waters were extracted from these sediment cores and analyzed for several chemical constituents at sea. The measured values were consistent with preliminary work from 1997. Systematic trends in chemical composition of these high pH fluids (up to 12.3) are observed with distance from the trench (proxy for the depth to slab). These trends include low alkalinity and high Ca near the trench (e.g., Blue Moon Seamount; 0.26 mmol alkalinity/kg and 55 mmol Ca/kg), and high alkalinity and low Ca further from the trench (e.g., Big Blue Seamount; 69 mmol alkalinity/kg and 0.14 mmol Ca/kg) consistent with carbonate dissolution at the top of the plate between depths of 17 km and 22 km. Here we report results from trace element analyses that similarly show trends across the forearc region. For example, fluids upwelling at Baby Blue Seamount have; 58 μ mol Sr/kg, 31 μ mol Li/kg, 1.4 μ mol Rb/kg, 10 nmol Cs/kg, 0.2 μ mol Ba/kg, 0.1 μ mol Mo/kg, 0.6 nmol U/kg, and 5 nmol Y/kg. In contrast, fluids from Big Blue Seamount, only 23 km away, have; 10 μ mol Sr/kg, 0.7 μ mol Li/kg, 6 μ mol Rb/kg, 0.2 μ mol Cs/kg, 60 nmol Ba/kg, 0.1 μ mol Mo/kg, 0.2 μ mol U/kg, and 0.1 nmol Y/kg.Trace element analyses for a host of chemical species and for each of the sampled seamounts offer insight into the conditions and interactions currently occurring within the Mariana seismogenic zone.

Transmutation effects on long-term Cs retention in phyllosilicate minerals from first principles.

PubMed

Sassi, Michel; Okumura, Masahiko; Machida, Masahiko; Rosso, Kevin M

2017-10-11

The accidental release and incorporation of radiocesium into soil minerals represents a massive environmental, technical and social challenge. Accurately forecasting the evolving distribution and fate of long- and medium-lived isotopes such as 137 Cs and 134 Cs over decadal time scales is essential. The cesium cation has long been modeled as a strongly and selectively sorbed species into clay mineral interlayers; however, because of the time scales involved by the radioisotopes half-lives, the effects of radioactive decay on Cs retention have been unknown. We report density functional theory (DFT) simulations of transmutation effects of radiocesium on long-term Cs retention in phlogopite. The calculations show that the progressive appearance of daughter product Ba 2+ is accompanied by a proportional increase in thermodynamic driving force to preferentially discharge remaining Cs, both radioactive and stable, back into aqueous solution. Based on thermodynamic analysis, the findings indicate that radiocesium transmutation provides a mean to weaken the binding of Cs in phyllosilicate minerals, therefore potentially involving a premature re-release of Cs back into the environment. In the case where radiogenic Ba 2+ ions accumulate in the mineral, collateral effects would ultimately be an increase in the overall interlayer binding energy and a lower resorption capacity.

Petrogenesis and tectonic implications of the Yadong leucogranites, southern Himalaya

NASA Astrophysics Data System (ADS)

Gou, Zhengbin; Zhang, Zeming; Dong, Xin; Xiang, Hua; Ding, Huixia; Tian, Zuolin; Lei, Hengcong

2016-07-01

The leucogranites in the Higher Himalayan Sequence (HHS) provide a probe to elucidate the crustal melting of continental collisional orogen. An integrated geochemical and geochronological study of the Yadong leucogranites, southern Himalaya, shows that these rocks have relatively high SiO2 contents of 69.77 to 75.32 wt.% and alumina saturation index (A/CNK) of 1.09-1.40, typical of peraluminous granites. They show moderately fractionated REE patterns with negative Eu anomalies, and are characterized by enriched LILE (Rb and Cs) and depleted HFSE (Zr, Hf, Nb and Ta). LA-ICP-MS U-Pb zircon dating of ten samples yields crystallization ages ranging from 21.0 to 11.7 Ma. The zircons have variable εHf(t) values of - 26.3 to - 3.5 and corresponding Hf two-stage model ages of 2.77-1.33 Ga. The present study reveals that the muscovite-biotite leucogranites (2ML) have higher TiO2, MgO, CaO, Sr, Ba and Zr contents, lower Rb/Sr ratios than the tourmaline-muscovite leucogranites (TML). Zircon and monazite saturation thermometry results show that the melt temperatures (681-784 °C) of the 2ML are 20-80 °C higher than those (663-705 °C) of the TML. Combining with previous results, we propose that the TML were derived from the muscovite-dehydration melting, whereas the 2ML dominantly resulted from the biotite-dehydration melting during the prograde metamorphism of the pelitic and felsic granulites of the HHS. Therefore, the Himalayan leucogranites were probably formed during the subduction of the Indian crust following the India and Asia collision.

Mixing Enthalpies of TbBr3-MBr Liquid Mixtures

NASA Astrophysics Data System (ADS)

Rycerz, L.; Gaune-Escard, M.

2001-12-01

The molar enthalpies of mixing, Δmix Hm in the binary liquid systems TbBr3-MBr (M = Li, Na, K, Rb, Cs) have been m easured with a Calvet-type high-tem perature microcalorimeter over the entire composition range with an accuracy of about 6 %. Mixing of the two liquid components was achieved by using the "break-off am poule" technique. All the investigated systems show negative enthalpies of mixing with a minim um value of approxim ately -1.25, - 8 .3 , -17.0, - 2 0 . 0 and -22.5 kJ mol -1, for M = Li, Na, K, Rb and Cs, respectively. The mixing enthalpy in the TbBr3- LiBr system is positive in the TbBr3-rich region. For all the systems, the enthalpy minimum occurs at mole fraction xTbBr3 ≈ 0.3 - 0.4. The molar enthalpies of form ation Δ formHm (3MBr, TbBr3, 1) for M = Li, Na, K, Rb and Cs at 1113 K (arising from the reaction 3M Br(1) +TbBr3(1) = (3MBr, TbBr3) (1)) are found to be -4 .8 , -31.3, -63.3, -70.3 and -8 1 .2 kJ mol-1 , respectively. The leastsquares coefficients A, B, C, D and E in the equation λ (kJ mol-1) = A + B x + C x2 + Dx3 + Ex4, where A is an interaction param eter and x = xTbBr , are also reported.

Adimensional theory of shielding in ultracold collisions of dipolar rotors

NASA Astrophysics Data System (ADS)

González-Martínez, Maykel L.; Bohn, John L.; Quéméner, Goulven

2017-09-01

We investigate the electric field shielding of ultracold collisions of dipolar rotors, initially in their first rotational excited state, using an adimensional approach. We establish a map of good and bad candidates for efficient evaporative cooling based on this shielding mechanism, by presenting the ratio of elastic over quenching processes as a function of a rescaled rotational constant B ˜=B /sE3 and a rescaled electric field F ˜=d F /B . B ,d ,F ,andsE 3 are respectively the rotational constant, the full electric dipole moment of the molecules, the applied electric field, and a characteristic dipole-dipole energy. We identify two groups of bi-alkali-metal dipolar molecules. The first group, including RbCs, NaK, KCs, LiK, NaRb, LiRb, NaCs, and LiCs, is favorable with a ratio over 1000 at collision energies equal to (or even higher than) their characteristic dipolar energy. The second group, including LiNa and KRb, is not favorable. More generally, for molecules well described by Hund's case b, our adimensional study provides the conditions of efficient evaporative cooling. The range of appropriate rescaled rotational constant and rescaled field is approximately B ˜≥108 and 3.25 ≤F ˜≤3.8 , with a maximum ratio reached for F ˜≃3.4 for a given B ˜. We also discuss the importance of the electronic van der Waals interaction on the adimensional character of our study.

Slab and Sediment Melting during Subduction Initiation: Mantle Plagiogranites from the Oman Ophiolite

NASA Astrophysics Data System (ADS)

Rollinson, H. R.

2014-12-01

Granitoid dykes up to several hundred metres wide and 2 km long are found in depleted harzburgites in the mantle section of the Oman ophiolite. They vary in composition from tonalite to potassic granite and are generally more potassic than the crustal plagiogranites found within the sheeted dyke complex higher up within the ophiolite stratigraphy. Some granites are strongly peraluminous and contain garnet and andalusite. They are geochemically variable, some with REE that are relatively unfractionated ((La/Yb)n= 3.5-6.0, flat middle to heavy REE, steep light REE) to those which are highly fractionated ((La/Yb)n= 28-220). On primitive-mantle normalised plots some have very high concentrations of fluid-mobile elements - Cs, Rb, Th, U and Pb. Few have significant Ta-Nb anomalies. On the Ca-Fe-Mg-Ti discrimination diagram of Patino Douce (J. Petrol., 1999) whole-rock compositions define a spectrum between felsic-pelite derived melts and amphibolite-derived melts. There is a chemical similarity between the least REE fractionated plagiogranites (generally tonalites and granodiorites) and melts of an amphibolitic parent. This is supported by the occurrence of mafic xenoliths in some dykes, the presence of hornblende and highly calcic cores (up to An85) in some plagioclase grains. Trace element modelling using Oman Geotimes lavas as the starting composition indicates that melting took place in the garnet stability field, although enrichment in the melt in Cs, Rb, Ba and Pb suggests that there was another component present in addition to the mafic parent. Other plagiogranites (trondhjemites and granites) have a strongly peraluminous chemistry and mineralogy and geochemical similarities with the Himalayan leucogranites implying that they were derived from a sedimentary protolith. These mantle plagiogranites are more prevalent in the northern outcrops of the ophiolite. The volume of granitoid melt and the depth of melting preclude their derivation from the sole of the ophiolite, rather they were derived during subduction by the partial melting of the slab and associated sediment and emplaced into the overlying mantle wedge. Current subduction-initiation models for supra-subduction ophiolites should integrate this process into their thinking.

Partial melting under conditions of filter pressing: field and geochemical evidence from the migmatites of NE Minnesota

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

Sheehan, T.J.; Bauer, R.L.; Nabelek, P.I.

1985-01-01

Amphibolite-grade Archean migmatites in the southern Vermilion Granitic Complex with well-defined paleosome-melanosome and melanosome-leucosome boundaries and with exceptionally wide melanosomes (on the order of centimeters) were studied to elucidate granite-forming processes during high-grade metamorphism. Metagreywacke paleosomes containing 50% plag, 28% qtz, 20% biot and minor hbld, and apat, have (Ce/Yb)/sub N/ = 13.5 to 21 with 650-960 ppm Ba, 42-110 ppm Rb, and 982-1159 ppm Sr. Melanosomes containing 45% plag, 35% biot, 20% hbld and minor qtz and apat, have (Ce/Yb)/sub N/ = 6.8 to 9.3 and have 950-1750 ppm Ba, 41-194 ppm Rb, and 1020-1926 ppm Sr. Leucosomes containingmore » 82% plag, 13% qtz, 5% biot and minor hbld and apat, have overall depleted REE patterns with positive Eu anomalies and 460-750 ppm Ba, 41-43 ppm Rb, and 1876-2106 ppm Sr, suggesting cumulate plagioclase. Mass balance calculations preclude formation of the melanosome from mixing the paleosomes and leucosomes. However, major and trace element modeling suggest that the leucosome formed by in situ partial melting followed by fractional crystallization and filter pressing which resulted in the removal of the residual liquid. Model REE patterns for the melt drive off by this process are REE enriched with a negative Eu anomaly. Such patterns which have been found in some low Sr granites are difficult to produce by simple belting models. Partial melting under conditions of tectonic stress may thus provide an explanation for such granites.« less

Alkali trace elements in Gale crater, Mars, with ChemCam: Calibration update and geological implications

NASA Astrophysics Data System (ADS)

Payré, V.; Fabre, C.; Cousin, A.; Sautter, V.; Wiens, R. C.; Forni, O.; Gasnault, O.; Mangold, N.; Meslin, P.-Y.; Lasue, J.; Ollila, A.; Rapin, W.; Maurice, S.; Nachon, M.; Le Deit, L.; Lanza, N.; Clegg, S.

2017-03-01

The Chemistry Camera (ChemCam) instrument onboard Curiosity can detect minor and trace elements such as lithium, strontium, rubidium, and barium. Their abundances can provide some insights about Mars' magmatic history and sedimentary processes. We focus on developing new quantitative models for these elements by using a new laboratory database (more than 400 samples) that displays diverse compositions that are more relevant for Gale crater than the previous ChemCam database. These models are based on univariate calibration curves. For each element, the best model is selected depending on the results obtained by using the ChemCam calibration targets onboard Curiosity. New quantifications of Li, Sr, Rb, and Ba in Gale samples have been obtained for the first 1000 Martian days. Comparing these data in alkaline and magnesian rocks with the felsic and mafic clasts from the Martian meteorite NWA7533—from approximately the same geologic period—we observe a similar behavior: Sr, Rb, and Ba are more concentrated in soluble- and incompatible-element-rich mineral phases (Si, Al, and alkali-rich). Correlations between these trace elements and potassium in materials analyzed by ChemCam reveal a strong affinity with K-bearing phases such as feldspars, K-phyllosilicates, and potentially micas in igneous and sedimentary rocks. However, lithium is found in comparable abundances in alkali-rich and magnesium-rich Gale rocks. This very soluble element can be associated with both alkali and Mg-Fe phases such as pyroxene and feldspar. These observations of Li, Sr, Rb, and Ba mineralogical associations highlight their substitution with potassium and their incompatibility in magmatic melts.

Synthesis and crystal structure of two new uranyl oxychloro-vanadate layered compounds: M7(UO 2) 8(VO 4) 2O 8Cl with M=Rb, Cs

NASA Astrophysics Data System (ADS)

Duribreux, I.; Saadi, M.; Obbade, S.; Dion, C.; Abraham, F.

2003-05-01

Two new alkali uranyl oxychloro vanadates M7(UO 2) 8(VO 4) 2O 8Cl with M=Rb, Cs, have been synthesized by solid-state reactions and their structures determined from single-crystal X-ray diffraction data. They crystallize in the orthorhombic system with space groups Pmcn and Pmmn, respectively. The a and b unit cell parameters are almost identical in both compounds while the c parameter in the Rb compound is doubled: Rb— a=21.427(5) Å, b=11.814(3) Å, c=14.203(3) Å, V=3595.1(1) Å 3, Z=4, ρmes=5.93(2) g/cm 3, ρcal=5.82(1) g/cm 3; Cs— a=21.458(3) Å, b=11.773(2) Å, c=7.495(1) Å, V=1893.6(5) Å 3, Z=2, ρmes=6.09(2) g/cm 3, ρcal=6.11(1) g/cm 3. A full-matrix least-squares refinement yielded R1=0.0221, w R2=0.0562 for 2675 independent reflections and R1=0.0386, w R2=0.1042 for 2446 independent reflections, for the Rb and Cs compounds, respectively. Data were collected with Mo( Kα) radiation and a charge coupled device (CCD) detector of a Bruker diffractometer. Both structures are characterized by [(UO 2) 8(VO 4) 2O 8Cl] n7 n- layers parallel to the (001) plane. The layers are built up from VO 4 tetrahedra, UO 7 and UO 6Cl pentagonal bipyramids, and UO 6 distorded octahedra. The UO 7 and UO 6Cl pentagonal bipyramids are associated by sharing opposite equatorial edges to form infinite chains (UO 5-UO 4Cl-UO 5) n parallel to the a axis. These chains are linked together by VO 4 tetrahedra, UO 6 octahedra, UO 7 corner sharing and UO 6Cl, Cl sharing. Both structures differ simply by the symmetry of the layers. The unit cell contains one centrosymmetric layer in the Cs compound, whereas in the two-layer unit cell of the Rb compound, two non-centrosymmetric consecutive layers are related by an inversion center. The layers appear to be held together by the alkali ions. The mobility of the M+ ions within the interlayer space in M7(UO 2) 8(VO 4) 2O 8Cl and carnotite analog compounds is compared.

Determining pre-eruptive compositions of late Paleozoic magma from kaolinized volcanic ashes: Analysis of glass inclusions in quartz microphenocrysts from tonsteins

NASA Astrophysics Data System (ADS)

Webster, James D.; Congdon, Roger D.; Lyons, Paul C.

1995-02-01

Glass inclusions in quartz microphenocrysts were analyzed for major and minor elements by electron microprobe and H, Li, Be, B, Rb, Sr, Y, Nb, Mo, Sn, Cs, Ce, Th, and U by ion microprobe. The phenocrysts and inclusions occur as fresh relicts in about eleven strongly kaolinized, air-fall volcanic ash units (tonsteins) that outcrop in five states located in the central Appalachian basin; the ashes were erupted during the Pennsylvanian. Even though the whole-rock tonstein samples are extremely altered, the glass trapped in quartz microphenocrysts preserves pre-eruptive melt compositions, and, consequently, the inclusions are useful for determining compositions of source magmas and identifying geochemical trends indicative of magmatic evolution. Interpretation of inclusion compositions indicates the strongly altered tonsteins were derived from potassium-enriched, metaluminous to mildly peraluminous magma(s). The tonsteins can be divided into two groups on the basis of trapped melt compositions: older tonsteins that have inclusions with high Sr and normative quartz contents and comparatively low concentrations of U, Th, Rb, Y, Cs, Nb, F, and Cl (±Be) and younger tonsteins whose inclusions contain low Sr and normative quartz and high concentrations of U, Th, Rb, Y, Cs, Nb, F, and Cl (±Be). In general, as concentrations of Sr decreased, the magmatic abundances of Rb, Y, Cs, Nb, U, Th, Cl, and F (±Be) increased. The associated magma or magmas were highly evolved, volatile enriched, and contained Rb, Nb, and Y abundances characteristic of continental within-plate granites; compositions ranged from high-silica rhyolite to topaz rhyolite. Pre-eruptive volatile abundances in the source magma(s) were generally high but also highly variable. Chlorine contents of melt(s) ranged from 0.02-0.23 wt%, and F ranged from 0.01-0.7 wt%. Concentrations of H 2O in melt(s) ranged from 1.6-6.5 wt%. The high pre-eruptive H 2O contents are consistent with large eruptive volumes indicating the precursor rhyolites, which weathered to tonsteins, were a result of plinian eruptions. Even though pre-eruptive water concentrations exhibit no recognizable trends with any elements studied, magmatic evolution appears to have been a strong function of F and H 2O in melt(s); the thermal stabilities of quartz and feldspar were controlled by F and H 2O activities at pressures of approximately 0.5-1 kbar.

Subalkaline andesite from Valu Fa Ridge, a back-arc spreading center in southern Lau Basin: petrogenesis, comparative chemistry, and tectonic implications

USGS Publications Warehouse

Vallier, T.L.; Jenner, G.A.; Frey, F.A.; Gill, J.B.; Davis, A.S.; Volpe, A.M.; Hawkins, J.W.; Morris, J.D.; Cawood, Peter A.; Morton, J.L.; Scholl, D. W.; Rautenschlein, M.; White, W.M.; Williams, Ross W.; Stevenson, A.J.; White, L.D.

1991-01-01

Tholeiitic andesite was dredged from two sites on Valu Fa Ridge (VFR), a back-arc spreading center in Lau Basin. Valu Fa Ridge, at least 200 km long, is located 40-50 km west of the active Tofua Volcanic Arc (TVA) axis and lies about 150 km above the subducted oceanic plate. One or more magma chambers, traced discontinuously for about 100 km along the ridge axis, lie 3-4 km beneath the ridge. The mostly aphyric and glassy lavas had high volatile contents, as shown by the abundance and large sizes of vesicles. An extensive fractionation history is inferred from the high SiO2 contents and FeO* MgO ratios. Chemical data show that the VFR lavas have both volcanic arc and back-arc basin affinities. The volcanic arc characteristics are: (1) relatively high abundances of most alkali and alkaline earth elements; (2) low abundances of high field strength elements Nb and Ta; (3) high U/Th ratios; (4) similar radiogenic isotope ratios in VFR and TVA lavas, in particular the enrichment of 87Sr 86Sr relative to 206Pb 204Pb; (5) high 238U 230Th, 230Th 232Th, and 226Ra 230Th activity ratios; and (6) high ratios of Rb/Cs, Ba/Nb, and Ba/La. Other chemical characteristics suggest that the VFR lavas are related to MORB-type back-arc basin lavas. For example, VFR lavas have (1) lower 87Sr 86Sr ratios and higher 143Nd 144Nd ratios than most lavas from the TVA, except samples from Ata Island, and are similar to many Lau Basin lavas; (2) lower Sr/REE, Rb/Zr, and Ba/Zr ratios than in arc lavas; and (3) higher Ti, Fe, and V, and higher Ti/V ratios than arc lavas generally and TVA lavas specifically. Most characteristics of VFR lavas can be explained by mixing depleted mantle with either small amounts of sediment and fluids from the subducting slab and/or an older fragment of volcanic arc lithosphere. The eruption of subalkaline andesite with some arc affinities along a back-arc spreading ridge is not unique. Collision of the Louisville and Tonga ridges probably activated back-arc extension that ultimately led to the creation and growth of Valu Fa Ridge. Some ophiolitic fragments in circum-Pacific and circum-Tethyan allochthonous terranes, presently interpreted to have originated in volcanic arcs, may instead be fragments of lithosphere that formed during early stages of seafloor spreading in a back-arc basin. ?? 1991.

The Rb problem in massive AGB stars.

NASA Astrophysics Data System (ADS)

Pérez-Mesa, V.; García-Hernández, D. A.; Zamora, O.; Plez, B.; Manchado, A.; Karakas, A. I.; Lugaro, M.

2017-03-01

The asymptotic giant branch (AGB) is formed by low- and intermediate-mass stars (0.8 M_{⊙} < M < 8 M_{⊙}) in their last nuclear-burning phase, when they develop thermal pulses (TP) and suffer extreme mass loss. AGB stars are the main contributor to the enrichment of the interstellar medium (ISM) and thus to the chemical evolution of galaxies. In particular, the more massive AGB stars (M > 4 M_{⊙}) are expected to produce light (e.g., Li, N) and heavy neutron-rich s-process elements (such as Rb, Zr, Ba, Y, etc.), which are not formed in lower mass AGB stars and Supernova explosions. Classical chemical analyses using hydrostatic atmospheres revealed strong Rb overabundances and high [Rb/Zr] ratios in massive AGB stars of our Galaxy and the Magellanic Clouds (MC), confirming for the first time that the ^{22}Ne neutron source dominates the production of s-process elements in these stars. The extremely high Rb abundances and [Rb/Zr] ratios observed in the most massive stars (specially in the low-metallicity MC stars) uncovered a Rb problem; such extreme Rb and [Rb/Zr] values are not predicted by the s-process AGB models, suggesting fundamental problems in our present understanding of their atmospheres. We present more realistic dynamical model atmospheres that consider a gaseous circumstellar envelope with a radial wind and we re-derive the Rb (and Zr) abundances in massive Galactic AGB stars. The new Rb abundances and [Rb/Zr] ratios derived with these dynamical models significantly resolve the problem of the mismatch between the observations and the theoretical predictions of the more massive AGB stars.

Prevalence of hepatitis B virus subgenotypes and basal core promoter, precore variants in patients with acute hepatitis B in central Vietnam.

PubMed

Hayashi, Kazuhiko; Katano, Yoshiaki; Chuong, Tran Xuan; Takeda, Yasushi; Ishigami, Masatoshi; Itoh, Akihiro; Hirooka, Yoshiki; Nakano, Isao; Huy, Tran Van; Minh, Nguyen Ngoc; Diem, Tran thi Minh; An, Dong thi Hoai; Phiet, Pham Hoang; Goto, Hidemi

2009-01-01

Hepatitis B virus (HBV) has been classified into 8 genotypes that have different geographic distributions. The clinical outcomes of acute hepatitis are dependent on genotype. The aim of this study was to investigate the distribution of HBV subgenotypes and basal core promoter (BCP)/precore (PC) regions in acute hepatitis patients in Central Vietnam to clarify the distributions and the clinical and virological differences. 27 patients with acute hepatitis B were studied. HBV subgenotypes and BCP/PC variants were determined by direct sequencing of the preS, BCP/PC regions, respectively. HBV subgenotypes B4/Ba (n = 22) and C1/Cs (n = 5) were detected. Of the 27 patients, 3 developed fulminant hepatic failure, and all were infected with B4/Ba. Three patients had a BCP mutation, and 10 patients had a PC mutation in subgenotype B4/Ba. Three patients with C1/Cs had a BCP mutation. Two of 3 patients who progressed to fulminant hepatic failure had T1762, A1764, and A1896 simultaneously. None of the patients with acute, self-limited hepatitis carried these triple mutations. The prevalent HBV subgenotypes in patients with acute hepatitis B in Central Vietnam were B4/Ba and C1/Cs. BCP/PC variants have an association with the development of fulminant hepatic failure in subgenotype B4/Ba. Copyright 2009 S. Karger AG, Basel.

Simple-to-Complex Transformation in Liquid Rubidium.

PubMed

Gorelli, Federico A; De Panfilis, Simone; Bryk, Taras; Ulivi, Lorenzo; Garbarino, Gaston; Parisiades, Paraskevas; Santoro, Mario

2018-05-18

We investigated the atomic structure of liquid Rb along an isothermal path at 573 K, up to 23 GPa, by X-ray diffraction measurements. By raising the pressure, we observed a liquid-liquid transformation from a simple metallic liquid to a complex one. The transition occurs at 7.5 ± 1 GPa which is slightly above the first maximum of the T-P melting line. This transformation is traced back to the density-induced hybridization of highest electronic orbitals leading to the accumulation of valence electrons between Rb atoms and to the formation of interstitial atomic shells, a behavior that Rb shares with Cs and is likely to be common to all alkali metals.

Determination of low (137)Cs concentration in seawater using ammonium 12-molybdophosphate adsorption and chemical separation method.

PubMed

Park, J H; Chang, B U; Kim, Y J; Seo, J S; Choi, S W; Yun, J Y

2008-12-01

A new method has been developed for analyzing (137)Cs in a small volume of seawater. Ammonium 12-molybdophosphate (AMP) was used two times during pretreatment procedure. The first step was to adsorb (137)Cs in seawater samples into AMP in order to reduce sample volume, and the second was to remove (87)Rb, interference nuclide for beta counting. The AMP adsorbing (137)Cs was dissolved by sodium hydroxide solution, and then (137)Cs was finally formed to be cesium chloroplatinate precipitate by adding 10% hexachloroplatinic acid. The beta rays emitted from (137)Cs were measured with a low background gas-proportional alpha/beta counter. This method was applied to several seawater samples taken in the East Sea of Korea. Compared to the routinely used gamma-spectrometry method, this new AMP method was reliable and suitable for analyzing (137)Cs in deep seawater.

Cubic-to-tetragonal structural phase transition in Rb{sub 1{minus}x}Cs{sub x}CaF{sub 3} solid solutions: Thermal expansion and EPR studies

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

Lahoz, F.; Villacampa, B.; Alcala, R.

1997-04-01

The influence of crystal mixing on the structural phase transitions in Rb{sub 1{minus}x}Cs{sub x}CaF{sub 3} (0{lt}x{lt}1) fluoroperovskite crystals has been studied by thermal expansion and EPR measurements of Ni{sup 2+} and Ni{sup 3+} paramagnetic probes. A cubic-to-tetragonal phase transition has been detected in crystals with x=0, 0.1, 0.21, 0.27, and 0.35. The critical temperature and the tetragonal distortion decrease as x increases. No transition was observed for x{ge}0.44. This transition shows a weak first-order component in the x=0 and 0.1 samples, which is progressively smeared out for x{gt}0.1, indicating a spatial distribution of the critical temperature in those crystals withmore » high ionic substitution rate. In RbCaF{sub 3}, another structural phase transition was observed at 20 K with a thermal hysteresis between 20 and 40 K. This transition has not been found in any of the mixed crystals.« less

Inclusion behavior of Cs, Sr, and Ba impurities in LiCl crystal formed by layer-melt crystallization: Combined first-principles calculation and experimental study

NASA Astrophysics Data System (ADS)

Choi, Jung-Hoon; Cho, Yung-Zun; Lee, Tae-Kyo; Eun, Hee-Chul; Kim, Jun-Hong; Kim, In-Tae; Park, Geun-Il; Kang, Jeung-Ku

2013-05-01

The pyroprocessing which uses a dry method to recycle spent oxide fuel generates a waste LiCl salt containing radioactive elements. To reuse LiCl salt, the radioactive impurities has to be separated by the purification process such as layer-melt crystallization. To enhance impurity separation efficiency, it is important to understand the inclusion mechanism of impurities within the LiCl crystal. Herein, we report the inclusion properties of impurities in LiCl crystals. First of all, the substitution enthalpies of Cs+, Sr2+, and Ba2+ impurities with 0-6 at% in LiCl crystal were evaluated via first-principles calculations. Also, the molten LiCl containing 1 mol of Cs+, Sr2+, and Ba2+ impurities was crystallized through the experimental layer-melt crystallization method. These substitution enthalpy and experiment clarify that a high substitution enthalpy should result in the high separation efficiency for an impurity. Furthermore, we find that the electron density map gives a clue to the mechanism for inclusion of impurities into LiCl crystal.

Theoretical investigation of the structural, elastic, electronic and optical properties of the ternary indium sulfide layered structures AInS2 (A = K, Rb and Cs)

NASA Astrophysics Data System (ADS)

Bouchenafa, M.; Sidoumou, M.; Halit, M.; Benmakhlouf, A.; Bouhemadou, A.; Maabed, S.; Bentabet, A.; Bin-Omran, S.

2018-02-01

Ab initio calculations were performed to investigate the structural, elastic, electronic and optical properties of the ternary layered systems AInS2 (A = K, Rb and Cs). The calculated structural parameters are in good agreement with the existing experimental data. Analysis of the electronic band structure shows that the three studied materials are direct band-gap semiconductors. Density of states, charge transfers and charge density distribution maps were computed and analyzed. Numerical estimations of the elastic moduli and their related properties for single-crystal and polycrystalline aggregates were predicted. The optical properties were calculated for incident radiation polarized along the [100], [010] and [001] crystallographic directions. The studied materials exhibit a noticeable anisotropic behaviour in the elastic and optical properties, which is expected due to the symmetry and the layered nature of these compounds.

Phase transition studied by 7Li nuclear magnetic resonance in LiXSO4 (X = K, Rb, Cs and NH4) single crystals

NASA Astrophysics Data System (ADS)

Lim, Ae Ran; Choh, Sung Ho; Jeong, Se-Young

2000-11-01

The temperature dependences of 7Li nuclear magnetic resonance in LiXSO4 (X = K, Rb, Cs, and NH4) single crystals grown by the slow evaporation method have been investigated by employing a Bruker FT NMR spectrometer. From the experimental data, the nuclear quadrupole constant, the asymmetry parameter and the principal axes of the EFG tensor were determined, and the results were compared with the crystal structure. The temperature dependences of the quadrupole parameters were explained with a single torsional mode of the Li-O bond by the Bayer theory. All the LiO4 tetrahedra in four different crystals showed torsional motion about the X-axis of the EFG tensor. Based on these results, the differences in atomic weight of X in the LiXSO4 single crystals are responsible for the differences in the torsional angular frequencies.

Binding energies of the ground triplet state a{sup 3}Σ{sub u}{sup +} of Rb{sub 2} and Cs{sub 2} in terms of the generalized Le Roy–Bernstein near-dissociation expansion

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

Sovkov, V. B.; Ivanov, V. S.

Formulae of Le Roy–Bernstein near-dissociation theory are derived in a general isotope–invariant form, applicable to any term in the rotational expansion of a diatomic ro-vibrational term value. It is proposed to use the generalized Le Roy–Bernstein expansion to describe the binding energies (ro-vibrational term values) of the ground triplet state a{sup 3}Σ{sub u}{sup +} of alkali metal dimers. The parameters of this description are determined for Rb{sub 2} and Cs{sub 2} molecules. This approach gives a recipe to calculate the whole variety of the binding energies with characteristic accuracies from ∼1 × 10{sup −3} to 1 × 10{sup −2} cm{supmore » −1} using a relatively simple algebraic equation.« less

γ -soft Ba 146 and the role of nonaxial shapes at N ≈ 90

DOE PAGES

Mitchell, A. J.; Lister, C. J.; McCutchan, E. A.; ...

2016-01-12

Low-spin states in the neutron-rich, N = 90 nuclide 146Ba were populated following β decay of 146Cs , with the goal of clarifying the development of deformation in barium isotopes through delineation of their nonyrast structures. Fission fragments of 146Cs were extracted from a 1.7-Ci 252Cf source and mass selected using the CAlifornium Rare Ion Breeder Upgrade (CARIBU) facility. Low-energy ions were deposited at the center of a box of thin β detectors, surrounded by a highly efficient high-purity Ge array. The new 146Ba decay scheme now contains 31 excited levels extending up to ~2.5 MeV excitation energy, double whatmore » was previously known. These data are compared to predictions from the interacting boson approximation (IBA) model. It appears that the abrupt shape change found at N = 90 in Sm and Gd is much more gradual in Ba and Ce, due to an enhanced role of the γ degree of freedom.« less

Alkali element constraints on Earth-Moon relations

NASA Technical Reports Server (NTRS)

Norman, M. D.; Drake, M. J.; Jones, J. H.

1994-01-01

Given their range of volatilities, alkali elements are potential tracers of temperature-dependent processes during planetary accretion and formation of the Earth-Moon system. Under the giant impact hypothesis, no direct connection between the composition of the Moon and the Earth is required, and proto-lunar material does not necessarily experience high temperatures. Models calling for multiple collisions with smaller planetesimals derive proto-lunar materials mainly from the Earth's mantle and explicitly invoke vaporization, shock melting and volatility-related fractionation. Na/K, K/Rb, and Rb/Cs should all increase in response to thermal volatization, so theories which derive the Moon substantially from Earth's mantle predict these ratios will be higher in the Moon than in the primitive mantle of the Earth. Despite the overall depletion of volatile elements in the Moon, its Na/K and K/Rb are equal to or less than those of Earth. A new model presented here for the composition of Earth's continental crust, a major repository of the alkali elements, suggests the Rb/Cs of the Moon is also less than that of Earth. Fractionation of the alkali elements between Earth and Moon are in the opposite sense to predictions based on the relative volatilities of these elements, if the Moon formed by high-T processing of Earth's mantle. Earth, rather than the Moon, appears to carry a signature of volatility-related fractionation in the alkali elements. This may reflect an early episode of intense heating on Earth with the Moon's alkali budget accreting from cooler material.

Synthesis and characterization of new fluoride-containing manganese vanadates A2Mn2V2O7F2 (A=Rb, Cs) and Mn2VO4F

NASA Astrophysics Data System (ADS)

Sanjeewa, Liurukara D.; McGuire, Michael A.; Smith Pellizzeri, Tiffany M.; McMillen, Colin D.; Ovidiu Garlea, V.; Willett, Daniel; Chumanov, George; Kolis, Joseph W.

2016-09-01

Large single crystals of A2Mn2V2O7F2 (A=Rb, Cs) and Mn2VO4F were grown using a high-temperature (~600 °C) hydrothermal technique. Single crystal X-ray diffraction and powder X-ray diffraction were utilized to characterize the structures, which both possess MnO4F2 building blocks. The A2Mn2V2O7F2 series crystallizes as a new structure type in space group Pbcn (No. 60), Z=4 (Rb2Mn2V2O7F2: a=7.4389(17) Å, b=11.574(3) Å, c=10.914(2) Å; Cs2Mn2V2O7F2: a=7.5615(15) Å, b=11.745(2) Å, c=11.127(2) Å). The structure is composed of zigzag chains of edge-sharing MnO4F2 units running along the a-axis, and interconnected through V2O7 pyrovanadate groups. Temperature dependent magnetic susceptibility measurements on this interesting one-dimensional structural feature based on Mn2+ indicated that Cs2Mn2V2O7F2 is antiferromagnetic with a Neél temperature, TN=~3 K and a Weiss constant, θ, of -11.7(1) K. Raman and infrared spectra were also analyzed to identify the fundamental V-O vibrational modes in Cs2Mn2V2O7F2. Mn2(VO4)F crystalizes in the monoclinic space group of C2/c (no. 15), Z=8 with unit cell parameters of a=13.559(2) Å, b=6.8036(7) Å, c=10.1408(13) Å and β=116.16(3)°. The structure is associated with those of triplite and wagnerite. Dynamic fluorine disorder gives rise to complex alternating chains of five-and six-coordinate Mn2+. These interpenetrating chains are additionally connected through isolated VO4 tetrahedra to form the condensed structure.

Synthesis and characterization of new fluoride-containing manganese vanadates A 2Mn 2V 2O 7F 2 (A=Rb, Cs) and Mn 2VO 4F

DOE PAGES

Sanjeewa, Liurukara D.; McGuire, Michael A.; Smith Pellizzeri, Tiffany M.; ...

2016-05-10

In large single crystals of A 2Mn 2V 2O 7F 2 (A=Rb, Cs) and Mn 2VO 4F were grown using a high-temperature (~600 °C) hydrothermal technique. We utilized single crystal X-ray diffraction and powder X-ray diffraction in order to characterize the structures, which both possess MnO 4F 2 building blocks. The A 2Mn 2V 2O 7F 2 series crystallizes as a new structure type in space group Pbcn (No. 60), Z=4 (Rb 2Mn 2V 2O 7F 2: a=7.4389(17) Å, b=11.574(3) Å, c=10.914(2) Å; Cs 2Mn 2V 2O 7F 2: a=7.5615(15) Å, b=11.745(2) Å, c=11.127(2) Å). The structure is composed ofmore » zigzag chains of edge-sharing MnO 4F 2 units running along the a-axis, and interconnected through V 2O 7 pyrovanadate groups. Temperature dependent magnetic susceptibility measurements on this interesting one-dimensional structural feature based on Mn 2+ indicated that Cs 2Mn 2V 2O 7F 2 is antiferromagnetic with a Neél temperature, TN=~3 K and a Weiss constant, θ, of -11.7(1) K. Raman and infrared spectra were also analyzed to identify the fundamental V–O vibrational modes in Cs 2Mn 2V 2O 7F 2. Mn 2(VO 4)F crystalizes in the monoclinic space group of C2/c (no. 15), Z=8 with unit cell parameters of a=13.559(2) Å, b=6.8036(7) Å, c=10.1408(13) Å and β=116.16(3)°. The structure is associated with those of triplite and wagnerite. Dynamic fluorine disorder gives rise to complex alternating chains of five-and six-coordinate Mn 2+. Our interpenetrating chains are additionally connected through isolated VO 4 tetrahedra to form the condensed structure.« less

Preliminary measurements of 135Cs with AMS

NASA Astrophysics Data System (ADS)

Yin, Xinyi; He, Ming; Dong, Kejun; Dou, Liang; Lan, Xiaoxi; Pang, Fangfang; Wu, Shaoyong; Jiang, Shan

2015-10-01

135Cs is an interesting nuclide in many research fields, especially in environmental study. Preliminary measurements of the long-lived 135Cs with accelerator mass spectrometry (AMS) have been developed with the HI-13 tandem AMS facility at China Institute of Atomic Energy (CIAE). In order to improve ion extracting current and depressing background interference, experiments were carried out on different ions of Cs extracted from different samples. It was found that Cs- extracted from CsNO3 can be used for AMS measurement of 135Cs. According to the preliminary results, the background level can be obtained with blanks was 135Ba/Cs ∼ 8.8 × 10-12 with the CIAE-AMS system.

Discrimination of fine-grained sediment provenance using geochemical elements on the inner shelf of the Korean Strait (South Sea), Korea

NASA Astrophysics Data System (ADS)

Um, I. K.; Choi, M. S.

2017-12-01

The central South Sea mud (CSSM) is located between the Heuksan mud belt (HMB) in the Yellow Sea and Korea Strait shelf mud (KSSM) in the East Sea and developed along the eastward transport pathway in the South Sea. Major elements (Al, Fe, Mg, and Ti), trace elements (Li, Cs, Sc, and Rb), and rare earth elements (REEs) in the fine-grained sediments (<15 μm) of thirty-two surface sediment samples on the CSSM were analyzed to determine the fine-grained sediment provenance. The spatial distribution of the analyzed elements showed a clear separation of the western (W-CSSM) and eastern (E-CSSM) regions of the CSSM. Concentrations of Fe, Ti, Mg, Sc, and REEs were higher in the W-CSSM, whereas concentrations of Al, Cs, Li, and Rb were higher in the E-CSSM. The ratios of trace metals ((Cs+Sc)/Li and Rb/Li) can be successfully used as a provenance indicator in the study area but REEs compositions could not be used to track the provenance of fine-grained sediments because of a grain size effect. The mixing relationships of the provenance indicators showed that the fine-grained sediments of the CSSM comprise a mixture of the sediments discharged from the Seomjin River (SRS) and sediments eroded and transported from the Heuksan mud belt (HMBS) area by the Korean coastal current. Sediments originating from the HMB were deposited mostly in the W-CSSM, whereas those from the Seomjin River were deposited mostly in the E-CSSM

Synthesis and structure of R{sub 2}[UO{sub 2}(NO{sub 3}){sub 2}(NCS){sub 2}] (R = Rb or Cs)

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

Serezhkin, V. N., E-mail: lserezh@samsu.ru; Peresypkina, E. V.; Grigor’eva, V. A.

2015-01-15

Crystals Rb{sub 2}[UO{sub 2}(NO{sub 3}){sub 2}(NCS){sub 2}] (I) and Cs{sub 2}[UO{sub 2}(NO{sub 3}){sub 2}(NCS){sub 2}] (II) have been synthesized and studied by IR spectroscopy and X-ray diffraction. Crystals I are monoclinic, with the following parameters: a = 12.2118(5) Å, b = 10.2545(3) Å, c = 11.8754(4) Å, β = 110.287(1)°, sp. gr. C2/c, Z = 4, and R = 0.0523. Crystals II are orthorhombic, with a = 13.7309(3) Å, b = 10.5749(2) Å, c = 10.1891(2) Å, sp. gr. Pnma, Z = 4, and R = 0.0411. The basic structural units of crystals I and II are one-core complexes [UO{submore » 2}(NO{sub 3}){sub 2}(NCS){sub 2}]{sup 2−}, which belong to the crystallochemical group cis-AB{sub 2}{sup 01}M{sub 2}{sup 1} (A = UO{sub 2}{sup 2+}, B{sup 01} = NO{sub 3}{sup −}, M{sup 1} = NCS{sup −}), which are combined into a framework via electrostatic interactions with ions of alkaline metals R (R = Rb or Cs). The structural features of crystals I and II, which condition the formation of [UO{sub 2}(NO{sub 3}){sub 2}(NCS){sub 2}]{sup 2−} complexes with a cis rather than a trans position of isothiocyanate ions in the coordination sphere of uranyl ions, are discussed.« less

Alkali trace elements in Gale crater, Mars, with ChemCam: Calibration update and geological implications

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

Payre, Valerie; Fabre, Cecile; Cousin, Agnes

The Chemistry Camera (ChemCam) instrument onboard Curiosity can detect minor and trace elements such as lithium, strontium, rubidium, and barium. Their abundances can provide some insights about Mars' magmatic history and sedimentary processes. We focus on developing new quantitative models for these elements by using a new laboratory database (more than 400 samples) that displays diverse compositions that are more relevant for Gale crater than the previous ChemCam database. These models are based on univariate calibration curves. For each element, the best model is selected depending on the results obtained by using the ChemCam calibration targets onboard Curiosity. New quantificationsmore » of Li, Sr, Rb, and Ba in Gale samples have been obtained for the first 1000 Martian days. Comparing these data in alkaline and magnesian rocks with the felsic and mafic clasts from the Martian meteorite NWA7533—from approximately the same geologic period—we observe a similar behavior: Sr, Rb, and Ba are more concentrated in soluble- and incompatible-element-rich mineral phases (Si, Al, and alkali-rich). Correlations between these trace elements and potassium in materials analyzed by ChemCam reveal a strong affinity with K-bearing phases such as feldspars, K-phyllosilicates, and potentially micas in igneous and sedimentary rocks. However, lithium is found in comparable abundances in alkali-rich and magnesium-rich Gale rocks. This very soluble element can be associated with both alkali and Mg-Fe phases such as pyroxene and feldspar. Here, these observations of Li, Sr, Rb, and Ba mineralogical associations highlight their substitution with potassium and their incompatibility in magmatic melts.« less

The isotopic and chemical evolution of Mount St. Helens

USGS Publications Warehouse

Halliday, A.N.; Fallick, A.E.; Dickin, A.P.; Mackenzie, A.B.; Stephens, W.E.; Hildreth, W.

1983-01-01

Isotopic and major and trace element analysis of nine samples of eruptive products spanning the history of the Mt. St. Helens volcano suggest three different episodes; (1) 40,000-2500 years ago: eruptions of dacite with ??{lunate}Nd = +5, ??{lunate}Sr = -10, variable ??18O, 206Pb/204Pb ??? 18.76, Ca/Sr ??? 60, Rb/Ba ??? 0.1, La/Yb ??? 18, (2) 2500-1000 years ago: eruptions of basalt, andesite and dacite with ??{lunate}Nd = +4 to +8, ??{lunate}Sr = -7 to -22, variable ??18O (thought to represent melting of differing mantle-crust reservoirs), 206Pb/204Pb = 18.81-18.87, variable Ca/Sr, Rb/Ba, La/Yb and high Zr, (3) 1000 years ago to present day: eruptions of andesite and dacite with ??{lunate}Nd = +6, ??{lunate}Sr = -13, ??18O ???6???, variable 206Pb/204Pb, Ca/Sr ??? 77, Rb/Ba = 0.1, La/Yb ??? 11. None of the products exhibit Eu anomalies and all are LREE enriched. There is a strong correlation between 87Sr/86Sr and differentiation indices. These data are interpreted in terms of a mantle heat source melting young crust bearing zircon and garnet, but not feldspar, followed by intrusion of this crustal reservoir by mantle-derived magma which caused further crustal melting and contaminated the crustal magma system with mafic components. Since 1000 years ago all the eruptions have been from the same reservoir which has displayed a much more gradual re-equilibration of Pb isotopic compositions than other components suggesting that Pb is being transported via a fluid phase. The Nd and Sr isotopic compositions lie along the mantle array and suggest that the mantle underneath Mt. St. Helens is not as depleted as MORB sources. There is no indication of seawater involvement in the source region. ?? 1983.

Alkali trace elements in Gale crater, Mars, with ChemCam: Calibration update and geological implications

DOE PAGES

Payre, Valerie; Fabre, Cecile; Cousin, Agnes; ...

2017-03-20

The Chemistry Camera (ChemCam) instrument onboard Curiosity can detect minor and trace elements such as lithium, strontium, rubidium, and barium. Their abundances can provide some insights about Mars' magmatic history and sedimentary processes. We focus on developing new quantitative models for these elements by using a new laboratory database (more than 400 samples) that displays diverse compositions that are more relevant for Gale crater than the previous ChemCam database. These models are based on univariate calibration curves. For each element, the best model is selected depending on the results obtained by using the ChemCam calibration targets onboard Curiosity. New quantificationsmore » of Li, Sr, Rb, and Ba in Gale samples have been obtained for the first 1000 Martian days. Comparing these data in alkaline and magnesian rocks with the felsic and mafic clasts from the Martian meteorite NWA7533—from approximately the same geologic period—we observe a similar behavior: Sr, Rb, and Ba are more concentrated in soluble- and incompatible-element-rich mineral phases (Si, Al, and alkali-rich). Correlations between these trace elements and potassium in materials analyzed by ChemCam reveal a strong affinity with K-bearing phases such as feldspars, K-phyllosilicates, and potentially micas in igneous and sedimentary rocks. However, lithium is found in comparable abundances in alkali-rich and magnesium-rich Gale rocks. This very soluble element can be associated with both alkali and Mg-Fe phases such as pyroxene and feldspar. Here, these observations of Li, Sr, Rb, and Ba mineralogical associations highlight their substitution with potassium and their incompatibility in magmatic melts.« less

Mixed-metal uranium(VI) iodates: hydrothermal syntheses, structures, and reactivity of Rb[UO(2)(CrO(4))(IO(3))(H(2)O)], A(2)[UO(2)(CrO(4))(IO(3))(2)] (A = K, Rb, Cs), and K(2)[UO(2)(MoO(4))(IO(3))(2)].

PubMed

Sykora, Richard E; McDaniel, Steven M; Wells, Daniel M; Albrecht-Schmitt, Thomas E

2002-10-07

The reactions of the molecular transition metal iodates A[CrO(3)(IO(3))] (A = K, Rb, Cs) with UO(3) under mild hydrothermal conditions provide access to four new, one-dimensional, uranyl chromatoiodates, Rb[UO(2)(CrO(4))(IO(3))(H(2)O)] (1) and A(2)[UO(2)(CrO(4))(IO(3))(2)] (A = K (2), Rb (3), Cs (4)). Under basic conditions, MoO(3), UO(3), and KIO(4) can be reacted to form K(2)[UO(2)(MoO(4))(IO(3))(2)] (5), which is isostructural with 2 and 3. The structure of 1 consists of one-dimensional[UO(2)(CrO(4))(IO(3))(H(2)O)](-) ribbons that contain uranyl moieties bound by bridging chromate and iodate anions as well as a terminal water molecule to create [UO(7)] pentagonal bipyramidal environments around the U(VI) centers. These ribbons are separated from one another by Rb(+) cations. When the iodate content is increased in the hydrothermal reactions, the terminal water molecule is replaced by a monodentate iodate anion to yield 2-4. These ribbons can be further modified by replacing tetrahedral chromate anions with MoO(4)(2)(-) anions to yield isostructural, one-dimensional [UO(2)(MoO(4))(IO(3))(2)](2)(-) ribbons. Crystallographic data: 1, triclinic, space group P(-)1, a = 7.3133(5) A, b = 8.0561(6) A, c = 8.4870(6) A, alpha = 88.740(1) degrees, beta = 87.075(1) degrees, gamma = 71.672(1) degrees, Z = 2; 2, monoclinic, space group P2(1)/c, a = 11.1337(5) A, b = 7.2884(4) A, c = 15.5661(7) A, beta = 107.977(1) degrees, Z = 4; 3, monoclinic, space group P2(1)/c, a = 11.3463(6) A, b = 7.3263(4) A, c = 15.9332(8) A, beta = 108.173(1) degrees, Z = 4; 4, monoclinic, space group P2(1)/n, a = 7.3929(5) A, b = 8.1346(6) A, c = 22.126(2) A, beta = 90.647(1) degrees, Z = 4; 5, monoclinic, space group P2(1)/c, a = 11.3717(6) A, b = 7.2903(4) A, c = 15.7122(8) A, beta = 108.167(1) degrees, Z = 4.

Estimation of cesium ion exchange distribution coefficients for concentrated electrolytic solutions when using crystalline silicotitanates

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

Zheng, Z.; Gu, D.; Anthony, R.G.

1995-06-01

Polzer et al.`s method combined with Bromley`s method for estimating activity coefficients and a Langmuir isotherm for cesium in a simple simulated waste solution containing 5.1 M NaNO{sub 3} and 0.6 M NaOH was used to estimate distribution coefficients for cesium in a complex simulated waste solution characteristic of the radioactive tank wastes at Hanford and other US Department of energy sites. The ion exchange material was a hydrous sodium crystalline silicotitanate, labeled TAM-5, which is being developed by Texas A and M University, Sandia National Laboratories, and UOP Associates. Cesium distribution coefficients collected by Bray et al. on amore » NCAW simulated waste solution were predicted with deviations of less than 25% for solutions containing 1 M, 3 M, and 5 M Na{sup +} and Na:Cs ratios of 10{sup 3}--10{sup 8}. The deviations were less than 5% for the solutions with 1 M Na{sup +}. Cesium distribution coefficients were also predicted and compared with values measured by Egan et al. for TAM-5 and for a storage tank supernate and a newly generated waste solution. Excellent results were obtained for the newly generated waste simulated solution, which did not contain potassium or rubidium.The predictions for the other simulated waste solution were significantly greater than the measured values, because of the presence of large concentrations of potassium or rubidium. The effect of competitive ion exchange between Cs, Rb, and K was not included in the theory. However, the effect of competitive ion exchange between Cs, Rb, and K was not included in the theory. However, the effect of competitive exchange of Cs, Rb, and K appears to be greater for the Oak Ridge simulated waste solution than for the NCAW waste.« less

Method for ultra-trace cesium isotope ratio measurements from environmental samples using thermal ionization mass spectrometry

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

Snow, Mathew S.; Snyder, Darin C.; Mann, Nick R.

2015-05-01

135Cs/ 137Cs isotope ratios can provide the age, origin and history of environmental Cs contamination. Relatively high precision 135Cs/ 137Cs isotope ratio measurements from samples containing femtogram quantities of 137Cs are needed to accurately track contamination resuspension and redistribution following environmental 137Cs releases; however, mass spectrometric analyses of environmental samples are limited by the large quantities of ionization inhibitors and isobaric interferences which are present at relatively high concentrations in the environment. We report a new approach for Cs purification from environmental samples. An initial ammonium molybdophosphate-polyacrylonitrile (AMP-PAN) column provides a robust method for extracting Cs under a wide varietymore » of sample matrices and mass loads. Cation exchange separations using a second AMP-PAN column result in more than two orders of magnitude greater Cs/Rb separation factors than commercially available strong cation exchangers. Coupling an AMP-PAN cation exchanging step to a microcation column (AG50W resin) enables consistent 2-4% (2σ) measurement errors for samples containing 3-6,000 fg 137Cs, representing the highest precision 135Cs/ 137Cs ratio measurements currently reported for soil samples at the femtogram level.« less

The response of shoot accumulation of trace elements in Chinese cabbage to microclimate modification.

PubMed

Moreno, D A; Villora, M G; Hernández, J; Castilla, N; Romer, L

2001-01-01

In three consecutive years of field experiments (1994-96), three different environmental conditions for the growth of Chinese cabbage (Brassica pekinensis (Lour) Rupr. cv. Nagaoka 50) were established by using two cover treatments (T1 and T2) and a control uncovered cultivation (T0). The T1 [50 microm polyethylene cover; 20 degrees C air temperature; 61.9% relative moisture; 207 Wm(-2) irradiance] and T2 [a 17 gm(-2) non-woven fleece; 18 degrees C; 63.4%; 205 Wm(-2) gave rise to differences in environmental conditions with respect to T0 [14 degrees C; 57.5%; 237 Wm(-2)]. We analysed chloride (Cl), barium (Ba). rubidium (Rb) and tin (Sn) in the whole tops of experimental plants. Chloride removal was high for Brassica pekinensis but considerably lower for Rb, giving intermediate values for Ba and Sn. The influence of environmental factors under T1 increased trace-element removal and enhanced the usefulness for phytoremedation.

Trace element concentrations in livers of polar bears from two populations in Northern and Western Alaska.

PubMed

Kannan, Kurunthachalam; Agusa, Tetsuro; Evans, Thomas J; Tanabe, Shinsuke

2007-10-01

Concentrations of 20 trace elements (V, Cr, Mn, Co, Cu, Zn, Rb, Sr, Mo, Ag, Cd, In, Sn, Sb, Cs, Ba, Hg, Tl, Pb, and Bi) were measured in livers of polar bears (Ursus maritimus) collected from Northern and Western Alaska from 1993 to 2002 to examine differences in the profiles of trace metals between the Beaufort Sea (Northern Alaska) and the Chukchi Sea (Western Alaska) subpopulations in Alaska. Among the trace elements analyzed, concentrations of Cu (50-290 microg/g, dry wt) in polar bear livers were in the higher range of values that have been reported for marine mammals. Concentrations of Hg in polar bears varied widely, from 3.5 to 99 microg/g dry wt, and the mean concentrations in polar bears were comparable to concentrations reported previously for several other species of marine mammals. Mean concentrations of Pb and Cd were 0.67 and 1.0 microg/g dry wt, respectively; these concentrations were lower than levels reported elsewhere for polar bears from Greenland and Canada. Age- and gender-related variations in the concentrations of trace elements in our polar bears were minimal. Concentrations of Hg decreased slowly in samples collected during 1993-2002, whereas Cd and Pb concentrations were found to be stable or slowly increasing, in the livers of Alaskan polar bears. Concentrations of Ag, Bi, Ba, Cu, and Sn were significantly higher in the Chukchi Sea subpopulation than in the Beaufort Sea subpopulation. Concentrations of Hg were significantly higher in the Beaufort Sea subpopulation than in the Chukchi Sea subpopulation. Differences in the profiles and concentrations of Hg, Ag, Bi, Ba, Cu, and Sn suggest that the sources of exposure to these trace elements between Western and Northern Alaskan polar bears are different, in agreement with findings reported earlier for several organic contaminants.

Candidate waste forms for immobilisation of waste chloride salt from pyroprocessing of spent nuclear fuel

NASA Astrophysics Data System (ADS)

Vance, E. R.; Davis, J.; Olufson, K.; Chironi, I.; Karatchevtseva, I.; Farnan, I.

2012-01-01

Sodalite/glass bodies prepared by hot isostatic pressing (HIPing) at ˜850 °C/100 MPa are candidates for immobilising fission product-bearing waste KCl-LiCl pyroprocessing salts. To study the capacity of sodalite to structurally incorporate such pyroprocessing salts, K, Li, Cs, Sr, Ba and La were individually targeted for substitution in a Na site in sodalite (Na vacancies targeted as charge compensators for alkaline and rare earths) and studied by X-ray diffraction and scanning electron microscopy after sintering in the range of 800-1000 °C. K and Li appeared to enter the sodalite, but Cs, Sr and Ba formed aluminosilicate phases and La formed an oxyapatite phase. However these non-sodalite phases have reasonable resistance to water leaching. Pure chlorapatite gives superior leach resistance to sodalite, and alkalis, alkaline and rare earth ions are generally known to enter chlorapatite, but attempts to incorporate simulated waste salt formulations into HIPed chlorapatite-based preparations or to substitute Cs alone into the structure of Ca-based chlorapatite were not successful on the basis of scanning electron microscopy. The materials exhibited severe water leachability, mainly in regard to Cs release. Attempts to substitute Cs into Ba- and Sr-based chlorapatites also did not look encouraging. Consequently the use of apatite alone to retain fission product-bearing waste pyroprocessing salts from electrolytic nuclear fuel reprocessing is problematical, but chlorapatite glass-ceramics may be feasible, albeit with reduced waste loadings. Spodiosite, Ca 2(PO 4)Cl, does not appear to be suitable for incorporation of Cl-bearing waste containing fission products.

GIS-based prediction of stream chemistry using landscape composition, wet areas, and hydrological flow pathways

NASA Astrophysics Data System (ADS)

Tiwari, Tejshree; Lidman, Fredrik; Laudon, Hjalmar; Lidberg, William; Ågren, Anneli M.

2017-01-01

Landscape morphology exerts strong, scale-dependent controls on stream hydrology and biogeochemistry in heterogeneous catchments. We applied three descriptors of landscape structure at different spatial scales based on new geographic information system tools to predict variability in stream concentrations for a wide range of solutes (Al, Ba, Be, Ca, Fe, K, Mg, Na, S, Si, Sr, Sc, Co, Cr, Ni, Cu, As, Se, Rb, Y, Cd, Sb, Cs, La, Pb, Th, U, DOC, and Cl) using a linear regression analysis. Results showed that less reactive elements, which can be expected to behave more conservatively in the landscape (e.g., Na, K, Ca, Mg, Cl, and Si), generally were best predicted from the broader-scale description of landscape composition (areal coverage of peat, tills, and sorted sediments). These results highlight the importance of mineral weathering as a source of some elements, which was best captured by landscape-scale descriptors of catchment structure. By contrast, more nonconservative elements (e.g., DOC, Al, Cd, Cs, Co, Th, Y, and U), were best predicted by defining wet areas and/or flow path lengths of different patches in the landscape. This change in the predictive models reflect the importance of peat deposits, such as organic-rich riparian zones and mire ecosystems, which are favorable environments for biogeochemical reactions of more nonconservative elements. As such, using this understanding of landscape influences on stream chemistry can provide improved mitigation strategies and management plans that specifically target source areas, so as to minimize mobilization of undesired elements into streams.

Using elemental profiles and stable isotopes to trace the origin of green coffee beans on the global market.

PubMed

Santato, Alessandro; Bertoldi, Daniela; Perini, Matteo; Camin, Federica; Larcher, Roberto

2012-09-01

A broad elemental profile incorporating 54 elements (Li, Be, B, Na, Mg, Al, P, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Se, Rb, Sr, Y, Mo, Pd, Ag, Cd, Sn, Sb, Te, Cs, Ba, La, Ce, Pr, Nd, Sm, Eu, Gd, Dy, Er, Tm, Yb, Re, Ir, Pt, Au, Hg, Tl, Pb, Bi and U) in combination with δ(2) H, δ(13) C, δ(15) N and δ(18) O was used to characterise the composition of 62 green arabica (Coffea arabica) and robusta (Coffea canephora) coffee beans grown in South and Central America, Africa and Asia, the four most internationally renowned areas of production. The δ(2) H, Mg, Fe, Co and Ni content made it possible to correctly assign 95% of green coffee beans to the appropriate variety. Canonical discriminant analysis, performed using δ(13) C, δ(15) N, δ(18) O, Li, Mg, P, K, Mn, Co, Cu, Se, Y, Mo, Cd, La and Ce correctly traced the origin of 98% of coffee beans. Copyright © 2012 John Wiley & Sons, Ltd.

Elemental ratios and enrichment factors in aerosols from the US-GEOTRACES North Atlantic transects

NASA Astrophysics Data System (ADS)

Shelley, Rachel U.; Morton, Peter L.; Landing, William M.

2015-06-01

The North Atlantic receives the highest aerosol (dust) input of all the oceanic basins. Dust deposition provides essential bioactive elements, as well as pollution-derived elements, to the surface ocean. The arid regions of North Africa are the predominant source of dust to the North Atlantic Ocean. In this study, we describe the elemental composition (Li, Na, Mg, Al, P, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Rb, Sr, Cd, Sn, Sb, Cs, Ba, La, Ce, Nd, Pb, Th, U) of the bulk aerosol from samples collected during the US-GEOTRACES North Atlantic Zonal Transect (2010/11) in order to highlight the differences between a Saharan dust end-member and the reported elemental composition of the upper continental crust (UCC), and the implications this has for identifying trace element enrichment in aerosols across the North Atlantic basin. As aerosol titanium (Ti) is less soluble than aerosol aluminum (Al), it is a more conservative tracer for lithogenic aerosols and trace element-to-Ti ratios. However, the presence of Ti-rich fine aerosols can confound the interpretation of elemental enrichments, making Al a more robust tracer of aerosol lithogenic material in this region.

Accumulation of Hg and other heavy metals in the Javan mongoose (Herpestes javanicus) captured on Amamioshima Island, Japan.

PubMed

Horai, Sawako; Minagawa, Mikiko; Ozaki, Hirokazu; Watanabe, Izumi; Takeda, Yasuo; Yamada, Katsushi; Ando, Tetsuo; Akiba, Suminori; Abe, Shintaro; Kuno, Katsuji

2006-10-01

Concentrations of 22 elements (Mg, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Rb, Sr, Mo, Ag, Cd, Sb, Cs, Ba, Tl, total Hg (T-Hg), Pb) and organic Hg (O-Hg) were examined in the liver, kidney and brain of the Javan mongoose (Herpestes javanicus) and in liver of the Amami rabbit (Pentalagus furnessi) from Amamioshima Island in Japan. Relatively high levels of T-Hg levels (from 1.75 to 55.5 microg g-1 wet wt.) were found in the Javan mongoose. As for a comparison of hepatic T-Hg concentrations between the two areas, there was no significant difference between the Javan mongoose in Amamioshima and those in the Okinawa islands. In addition, T-Hg levels in the livers of the Amami rabbit were the same as in the livers of other herbivorous mammals. Taken together, it suggested that T-Hg accumulation in the livers of the Javan mongoose was not affected by the environment but by a specific physiological mechanism. The comparison of Hg and other heavy metal accumulations between terrestrial mammals (13 species, 61 individuals) including the Javan mongoose and marine mammals (18 species, 508 individuals) were also discussed.

Heavy metal and trace elements in riparian vegetation and macrophytes associated with lacustrine systems in Northern Patagonia Andean Range.

PubMed

Juárez, Andrea; Arribére, María A; Arcagni, Marina; Williams, Natalia; Rizzo, Andrea; Ribeiro Guevara, Sergio

2016-09-01

Vegetation associated with lacustrine systems in Northern Patagonia was studied for heavy metal and trace element contents, regarding their elemental contribution to these aquatic ecosystems. The research focused on native species and exotic vascular plant Salix spp. potential for absorbing heavy metals and trace elements. The native species studied were riparian Amomyrtus luma, Austrocedrus chilensis, Chusquea culeou, Desfontainia fulgens, Escallonia rubra, Gaultheria mucronata, Lomatia hirsuta, Luma apiculata, Maytenus boaria, Myrceugenia exsucca, Nothofagus antarctica, Nothofagus dombeyi, Schinus patagonicus, and Weinmannia trichosperma, and macrophytes Hydrocotyle chamaemorus, Isöetes chubutiana, Galium sp., Myriophyllum quitense, Nitella sp. (algae), Potamogeton linguatus, Ranunculus sp., and Schoenoplectus californicus. Fresh leaves were analyzed as well as leaves decomposing within the aquatic bodies, collected from lakes Futalaufquen and Rivadavia (Los Alerces National Park), and lakes Moreno and Nahuel Huapi (Nahuel Huapi National Park). The elements studied were heavy metals Ag, As, Cd, Hg, and U, major elements Ca, K, and Fe, and trace elements Ba, Br, Co, Cr, Cs, Hf, Na, Rb, Se, Sr, and Zn. Geochemical tracers La and Sm were also determined to evaluate contamination of the biological tissues by geological particulate (sediment, soil, dust) and to implement concentration corrections.

Enhanced electrokinetic properties and antimicrobial activities of biodegradable chitosan/organo-bentonite composites.

PubMed

Cabuk, Mehmet; Alan, Yusuf; Unal, H Ibrahim

2017-04-01

In this study, chitosan (CS), Na + -bentonite (Na + -BNT) and chitosan/organo-bentonite (CS/O-BNT) biodegradable composites having three different compositions were investigated. Electrokinetic measurements were examined in aqueous medium by taking the effects pH, electrolytes (NaCl and BaCl 2 ), surfactants (CTAB and SDS), and temperature into account. It was noticed that the initial ζ-potential of Na + -BNT shifted from negative (ζ=-35mV) to positive region (ζ=+13mV) with increasing polycationic CS content in the composite structure as aimed. Divalent 2:1 electrolyte (BaCl 2 ) caused to shift the ζ-potentials of all the dispersions to more positive regions. While the most negative effect on ζ-potential of the composites was reached with SDS, which reduced the value of ζ-potential to -39mV for CS(1)/O-BNT composite, the most positive effect was monitored with CTAB (ζ=+40mV) for CS(3)/O-BNT composite. Further, the composites were tested against various bacterial (Gram-positive and Gram-negative) and fungal microorganisms at various concentrations and results obtained were compared with the reference antibiotics and fungicide. According to inhibition zone values accomplished, antibacterial and antifungal activities of the CS/O-BNT composites are increased with increasing CS content as proportional with their positive ζ-potential values. Copyright © 2017 Elsevier Ltd. All rights reserved.

Magnetoencephalography with a Cs-based high-sensitivity compact atomic magnetometer

NASA Astrophysics Data System (ADS)

Sheng, Jingwei; Wan, Shuangai; Sun, Yifan; Dou, Rongshe; Guo, Yuhao; Wei, Kequan; He, Kaiyan; Qin, Jie; Gao, Jia-Hong

2017-09-01

In recent years, substantial progress has been made in developing a new generation of magnetoencephalography (MEG) with a spin-exchange relaxation free (SERF)-based atomic magnetometer (AM). An AM employs alkali atoms to detect weak magnetic fields. A compact AM array with high sensitivity is crucial to the design; however, most proposed compact AMs are potassium (K)- or rubidium (Rb)-based with single beam configurations. In the present study, a pump-probe two beam configuration with a Cesium (Cs)-based AM (Cs-AM) is introduced to detect human neuronal magnetic fields. The length of the vapor cell is 4 mm, which can fully satisfy the need of designing a compact sensor array. Compared with state-of-the-art compact AMs, our new Cs-AM has two advantages. First, it can be operated in a SERF regime, requiring much lower heating temperature, which benefits the sensor with a closer distance to scalp due to ease of thermal insulation and less electric heating noise interference. Second, the two-beam configuration in the design can achieve higher sensitivity. It is free of magnetic modulation, which is necessary in one-beam AMs; however, such modulation may cause other interference in multi-channel circumstances. In the frequency band between 10 Hz and 30 Hz, the noise level of the proposed Cs-AM is approximately 10 f T/Hz1/2, which is comparable with state-of-the-art K- or Rb-based compact AMs. The performance of the Cs-AM was verified by measuring human auditory evoked fields (AEFs) in reference to commercial superconducting quantum interference device (SQUID) channels. By using a Cs-AM, we observed a clear peak in AEFs around 100 ms (M100) with a much larger amplitude compared with that of a SQUID, and the temporal profiles of the two devices were in good agreement. The results indicate the possibility of using the compact Cs-AM for MEG recordings, and the current Cs-AM has the potential to be designed for multi-sensor arrays and gradiometers for future neuroscience studies.

Inclusion property of Cs, Sr, and Ba impurities in LiCl crystal formed by layer-melt crystallization

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

Choi, Jung-Hoon; Cho, Yung-Zun; Lee, Tae-Kyo

Pyroprocessing is one of the promising technologies enabling the recycling of spent nuclear fuels from a commercial light water reactor (LWR). In general, pyroprocessing uses dry molten salts as electrolytes. In particular, LiCl waste salt after pyroprocessing contains highly radioactive I/II group fission products mainly composed of Cs, Sr, and Ba impurities. Therefore, it is beneficial to reuse LiCl salt in the pyroprocessing as an electrolyte for economic and environmental issues. Herein, to understand the inclusion property of impurities within LiCl crystal, the physical properties such as lattice parameter change, bulk modulus, and substitution enthalpy of a LiCl crystal havingmore » 0-6 at% Cs{sup +} or Ba{sup 2+} impurities under existence of 1 at% Sr{sup 2+} impurity were calculated via the first-principles density functional theory. The substitution enthalpy of LiCl crystals having 1 at% Sr{sup 2+} showed slightly decreased value than those without Sr{sup 2+} impurity. Therefore, through the substitution enthalpy calculation, it is expected that impurities will be incorporated within LiCl crystal as co-existed form rather than as a single component form. (authors)« less

Excited-state absorption in Er: BaY2F8 and Cs3Er2Br9 and comparison with Er: LiYF4

NASA Astrophysics Data System (ADS)

Pollnau, M.; Lüthy, W.; Weber, H. P.; Krämer, K.; Güdel, H. U.; McFarlane, R. A.

1996-04-01

The influence of Excited-State Absorption (ESA) on the green laser transition and the overlap of Ground-State Absorption (GSA) and ESA for 970 nm upconversion pumping in erbium is investigated in Er3+ : BaY2F8 and Cs3Er2Br9. Results are compared to Er3+ : LiYF4. In Er3+: BaY2F8, a good overlap between GSA and ESA is found at 969 nm in one polarization direction. The emission cross section at 550 nm is a factor of two smaller than in LiYF4. In Cs3Er2Br9, the smaller Stark splitting of the levels shifts the wavelengths of the green emission and ESA from4 I 1 3/2 off resonance. It enhances, however, ground-state reabsorption. The emission cross section at 550 nm is comparable to LiYF4. Upconversion leads to significant green fluorescence from2 H 9/2. A significant population of the4 I 11/2 level and ESA at 970 nm are not present under 800 nm pumping.

Assessment of magmatic vs. metasomatic processes in rare-metal granites: A case study of the Cínovec/Zinnwald Sn-W-Li deposit, Central Europe

NASA Astrophysics Data System (ADS)

Breiter, Karel; Ďurišová, Jana; Hrstka, Tomáš; Korbelová, Zuzana; Hložková Vaňková, Michaela; Vašinová Galiová, Michaela; Kanický, Viktor; Rambousek, Petr; Knésl, Ilja; Dobeš, Petr; Dosbaba, Marek

2017-11-01

The Cínovec rare-metal granite in the eastern segment of the Krušné Hory/Erzgebirge (Czech Republic/Germany) formed in the final stage of the magmatic evolution of the late Variscan volcano-plutonic system known as the Teplice caldera. The granite is slightly peraluminous; enriched in F, Li, Rb, Cs, Nb, Ta, Sn, W, Sc and U; and poor in P, Mg, Ti, Sr and Ba. The uppermost part of the granite cupola hosts a greisen-type Sn-W-Li deposit. Borehole CS-1 permits to study vertical evolution of the pluton to a depth of 1597 m. A combination of textural and chemical methods was applied to whole-rock and mineral samples to identify the extent of magmatic and metasomatic processes during the differentiation of the pluton and formation of the deposit. As indicated by textural and chemical data, the Cínovec pluton consists of two cogenetic intrusive bodies: a relatively homogeneous biotite granite at depths greater than 735 m, and a strongly differentiated zinnwaldite granite above this level. The pronounced differentiation of the zinnwaldite granite magma resulted in further increases in F, Li, Rb, Nb and Ta. A high degree of magmatic fractionation is documented by decreases in the K/Rb ratio from 25 to 15 and in the Zr/Hf ratio from 10 to 5. The increasing influence of the fluid is highlighted by a decrease in the Y/Ho ratio from 29 to 17. The following genetic scenario is proposed: the intrusion of the zinnwaldite granite magma reached subvolcanic conditions and a hem of fine-grained porphyritic granite crystallized along the upper contact. Separation of the first portion of fluid from the oversaturated melt promoted explosive degassing and the origin of breccia pipes. Subsequently, the zinnwaldite granite magma crystallized simultaneously from the upper contact and the footwall inwards. The residual melt between the two crystallizing fronts became enriched in water and volatiles to reach second saturation ("second boiling"). Segregated fluids escaped upwards, causing hydrofracturing of the overlying granite, while the water-poor residuum crystallized in situ in the form of mica-free granite. F- and Li-rich fluids invoked greisenization and created quartz-zinnwaldite veins. Alkalis liberated from feldspars destroyed during the greisenization induced local albitization in the uppermost part of the cupola and K-feldspathisation in its deeper part. The distribution of Sn and W was controlled by fluid processes, while Nb and Ta mainly crystallized from the melt. The results from Cínovec are universally applicable to shallow-intruded rare-metal granites regardless of A- or S-types of the primary magma.

Phase-Pure and Multiphase Ceramic Waste Forms: Microstructure Evolution and Cesium Immobilization

NASA Astrophysics Data System (ADS)

Tumurugoti, Priyatham

Efforts of this thesis are directed towards developing ceramic waste forms as a potential replacement for the conventional glass waste forms for the safe immobilization and disposal of nuclear wastes from the legacy weapons programs as well as commercial power production. The body of this work consists of two equal parts with first focused on multiphase waste form containing hollandite as major phase and the later, on single-phase hollandites for Cs incorporation. Part I: Multiphase waste forms:. Hollandite-rich multiphase waste form compositions processed by melt-solidification and spark plasma sintering (SPS) were characterized, compared, and validated for nuclear waste incorporation. Phase identification by X-ray diffraction (XRD) and electron back-scattered diffraction (EBSD) confirm hollandite as the major phase present in these samples along with perovskite, pyrochlore and zirconolite. Distribution of select elements observed by wavelength dispersive spectroscopy (WDS) maps indicate that Cs forms a secondary phase during SPS processing, which is considered undesirable. On the other hand Cs partitioned into hollandite phase in melt-processed samples. Further analysis of hollandite structure in melt-processed composition, by selected area electron diffraction (SAED), reveals ordered arrangement of tunnel ions (Ba/Cs) and vacancies, suggesting efficient Cs incorporation into the lattice. Following the microstructural analysis, the crystallization behavior of the multiphase composition during melt-processing was studied. The phase assemblage and evolution of hollandite, zirconolite, pyrochlore, and perovskite type structures during melt processing were studied using thermal analysis, in-situ XRD, and scanning electron microscopy (SEM). Samples prepared by melting followed by annealing and quenching were analyzed to determine and measure the progression of the phase assemblage. Samples were melted at 1500°C and heat-treated at crystallization temperatures of 1285°C and 1325°C corresponding to exothermic events identified from differential scanning calorimetry (DSC) measurements. Results indicate that the selected multiphase composition partially melts at 1500°C with hollandite coexisting as crystalline phase. Perovskite and zirconolite phases crystallized from the residual melt at temperatures below 1350°C. Depending on their respective thermal histories, different quenched samples were found to have different phase assemblages including phases such as perovskite, zirconolite and TiO2. Part II: Single phase waste forms. Hollandites with compositions Ba1.15-xCs2xCr 2.3Ti5.7O16 have been identified as promising lattices to host Cs. Series of compositions with 0 ≤ x ≤ 1.15 were prepared by sol-gel synthesis, characterized, and analyzed for Cs retention properties. Phase-pure hollandites adopting monoclinic symmetry (I2/m) were observed to form in the compositional range 0 ≤ x ≤ 0.4. Structural models for the compositions: x = 0, 0.15, and 0.25, were developed from Rietveld analysis of powder XRD and neutron diffraction data. Refined anisotropic displacement parameters (beta ij) for Ba and Cs ions in the hollandite tunnels indicate local disorder of Ba/Cs along the tunnel direction. In addition, weak super lattice reflections have also been observed in XRD patterns. Our data suggests the presence of supercell structures with ordered tunnel cations for the phase-pure hollandites studied. Finally, the performance of phase-pure hollandites have been evaluated qualitatively by chemical durability testing and ion-irradiation experiments. Elemental analysis of the leachants after 7-day leach tests show that Cs and Cr were extracted from the lattice together. No direct correlation between structural parameters or Cs content was observed. The simulated light-ion (He2+) and heavy-ion (Kr3+) irradiation experiments reveal that all the hollandite compositions studied undergo amorphization during alpha-decay events, and the extent of it increases with the Cs content. In summary, the present work validates melt-processing as an effective method to prepare multiphase waste forms with the desired phase assemblage. Ba1.15-xCs2xCr2.3Ti5.7O16 hollandite has been identified as an effective ceramic host for Cs immobilization and appropriate structural models for hollandites with different Cs levels have been developed. The structural information may be used to study or simulate the lattice-environment interaction.

Structural and dynamical trends in alkali-metal silanides characterized by neutron-scattering methods

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

Tang, Wan Si; Dimitrievska, Mirjana; Chotard, Jean -Noel

Structural, vibrational, and dynamical properties of the mono- and mixed-alkali silanides (MSiH 3, where M = K, Rb, Cs, K 0.5Rb 0.5, K 0.5Cs 0.5, and Rb 0.5Cs 0.5) were investigated by various neutron experiments, including neutron powder diffraction (NPD), neutron vibrational spectroscopy (NVS), neutron-scattering fixed-window scans (FWSs), and quasielastic neutron scattering (QENS) measurements. Structural characterization showed that the mixed compounds exhibit disordered (α) and ordered (β) phases for temperatures above and below about 200–250 K, respectively, in agreement with their monoalkali correspondents. Vibrational and dynamical properties are strongly influenced by the cation environment; in particular, there is a redmore » shift in the band energies of the librational and bending modes with increasing lattice size as a result of changes in the bond lengths and force constants. Additionally, slightly broader spectral features are observed in the case of the mixed compounds, indicating the presence of structural disorder caused by the random distribution of the alkali-metal cations within the lattice. FWS measurements upon heating showed that there is a large increase in reorientational mobility as the systems go through the order–disorder (β–α) phase transition, and measurements upon cooling of the α-phase revealed the known strong hysteresis for reversion back to the β-phase. Interestingly, at a given temperature, among the different alkali silanide compounds, the relative reorientational mobilities of the SiH 3 – anions in the α- and β-phases tended to decrease and increase, respectively, with increasing alkali-metal mass. Lastly, this dynamical result might provide some insights concerning the enthalpy–entropy compensation effect previously observed for these potentially promising hydrogen storage materials.« less

Determination of trace elements in epiphytic lichens from Bandar Baru Bangi, Selangor using INAA method

NASA Astrophysics Data System (ADS)

Khairudin, Nurshafiq Ezam; Siong, Khoo Kok; Siong, Wee Boon

2014-02-01

Lichens have been used as effective biomonitors of atmospheric pollutants as they can take up nutrients and pollutants directly from the atmosphere. In this study, trace element contents in epiphytic lichens were determined using INAA method. Samples were collected from 7 sampling locations around Bandar Baru Bangi, Selangor. The elements detected were As (1.73+0.85 mg/kg), Ce (3.65+1.91 mg/kg), Co (0.29+0.12 mg/kg), Cr (5.92+3.54 mg/kg), Cs (0.92+0.25 mg/kg), Eu (0.03+0.02 mg/kg), Fe (1280+760 mg/kg), Hf (0.37+0.18 mg/kg), La (1.52+0.89 mg/kg), Rb (27.7+4.8 mg/kg), Sc (0.33+0.19 mg/kg), Sm (0.28+0.16 mg/kg), Th (1.21+0.62 mg/kg) and Zn (116+27 mg/kg). Comparisons were then made between the elemental concentrations obtained and the baseline data from literature. Results showed that most of the elements were within the concentration range of the baseline data. Enrichment factors (EF) of the trace element in lichens showed that most of the elements were within the range of the baseline data except for As which was found to be slightly enriched (EF: 13.2 - 28.5). Regression analysis indicated significant correlation (p<0.05) with Sc for most of the elements which signifies crustal input except for Cs and Rb. The poor correlations of Cs and Rb with Sc may be due to the mobility of these elements. In summary, trace element data obtained using INAA were very useful and demonstrated that lichens were suitable biomonitors for identifying potential trace element pollutants in ambient air around the sampling area.

Distributions of Li+, Na+ K+, Rb+, and Cs+ tracer ions in erythrocytes at 38 degrees C in relation to entry rates of these ions into cells at 0 degree C.

PubMed

Salminen, S; Ekman, A; Rastas, J

2000-01-01

Forces that are able to transport Na+ and K+ into two compartments were investigated. A modified Nernst-Planck equation for coupled flows of electric current, water, and ions was integrated. The result shows that if alkali ions in the ion channel of the cell membrane are separated by their electric-current-induced inward flows against an electro-osmotic outward flow of water, the logarithms of the stationary cell/medium distributions of these ions should be proportional to the inverse of their diffusion mobilities. The relationship was tested in human erythrocytes. From inward and outward movements of tracer alkali ions, calculations were made to obtain their stationary distributions at infinite time. The cell/medium distributions determined in this way at 38 degrees C are Li+ = 0.59, 22Na+ = 0.044, 42K+ = 10.0, 86Rb+ = 11.9, and 137Cs+ = 3.07. The entry rates of ions into the cell at 0 degrees C are understood to represent their diffusion mobilities in the pump channel. The entry rates are Li+ = 1.44, 2Na+ = 1, 42K+ = 2.22, 86Rb+ = 2.39, and 137Cs+ = 1.72 relative to that of 22Na+. There is an expected negative correlation between the logarithms of the stationary cell/ medium distributions at 38 degrees C and the inverse of the entry rates into the cell at 0 degrees C for the five ions. It is suggested that the proposed physical forces cause the separation of alkali ions in the channel of Na,K-ATPase.

Structural and dynamical trends in alkali-metal silanides characterized by neutron-scattering methods

DOE PAGES

Tang, Wan Si; Dimitrievska, Mirjana; Chotard, Jean -Noel; ...

2016-09-02

Structural, vibrational, and dynamical properties of the mono- and mixed-alkali silanides (MSiH 3, where M = K, Rb, Cs, K 0.5Rb 0.5, K 0.5Cs 0.5, and Rb 0.5Cs 0.5) were investigated by various neutron experiments, including neutron powder diffraction (NPD), neutron vibrational spectroscopy (NVS), neutron-scattering fixed-window scans (FWSs), and quasielastic neutron scattering (QENS) measurements. Structural characterization showed that the mixed compounds exhibit disordered (α) and ordered (β) phases for temperatures above and below about 200–250 K, respectively, in agreement with their monoalkali correspondents. Vibrational and dynamical properties are strongly influenced by the cation environment; in particular, there is a redmore » shift in the band energies of the librational and bending modes with increasing lattice size as a result of changes in the bond lengths and force constants. Additionally, slightly broader spectral features are observed in the case of the mixed compounds, indicating the presence of structural disorder caused by the random distribution of the alkali-metal cations within the lattice. FWS measurements upon heating showed that there is a large increase in reorientational mobility as the systems go through the order–disorder (β–α) phase transition, and measurements upon cooling of the α-phase revealed the known strong hysteresis for reversion back to the β-phase. Interestingly, at a given temperature, among the different alkali silanide compounds, the relative reorientational mobilities of the SiH 3 – anions in the α- and β-phases tended to decrease and increase, respectively, with increasing alkali-metal mass. Lastly, this dynamical result might provide some insights concerning the enthalpy–entropy compensation effect previously observed for these potentially promising hydrogen storage materials.« less

Spatial Disorientation: Past, Present, and Future

DTIC Science & Technology

2014-03-27

NJ: Pearson Education, Inc. 10. Stanton, N.A., Booth, R.T., and Stammers , R.B., 1992, “Alarms in human supervisory control: a human factors...perspective,” International Journal of Computer Integrated Manufacturing, 5(2), 81-93. 11. Dismukes, R.K., Berman, B.A., and Loukopoulos, L.D., 2007 , The

Trace element abundances in major minerals of Late Permian coals from southwestern Guizhou province, China

USGS Publications Warehouse

Zhang, Jiahua; Ren, D.; Zheng, C.; Zeng, R.; Chou, C.-L.; Liu, J.

2002-01-01

Fourteen samples of minerals were separated by handpicking from Late Permian coals in southwestern Guizhou province, China. These 14 minerals were nodular pyrite, massive recrystallized pyrite, pyrite deposited from low-temperature hydrothermal fluid and from ground water; clay minerals; and calcite deposited from low-temperature hydrothermal fluid and from ground water. The mineralogy, elemental composition, and distribution of 33 elements in these samples were studied by optical microscopy, scanning electron microscope equipped with energy-dispersive X-ray spectrometer (SEM-EDX), X-ray diffraction (XRD), cold-vapor atomic absorption spectrometry (CV-AAS), atomic fluorescence spectrometry (AFS), inductively coupled-plasma mass spectrometry (ICP-MS), and ion-selective electrode (ISE). The results show that various minerals in coal contain variable amounts of trace elements. Clay minerals have high concentrations of Ba, Be, Cs, F, Ga, Nb, Rb, Th, U, and Zr. Quartz has little contribution to the concentration of trace elements in bulk coal. Arsenic, Mn, and Sr are in high concentrations in calcite. Pyrite has high concentrations of As, Cd, Hg, Mo, Sb, Se, Tl, and Zn. Different genetic types of calcite in coal can accumulate different trace elements; for example Ba, Co, Cr, Hg, Ni, Rb, Sn, Sr, and Zn are in higher concentrations in calcite deposited from low-temperature hydrothermal fluid than in that deposited from ground water. Furthermore, the concentrations of some trace elements are quite variable in pyrite; different genetic types of pyrites (Py-A, B, C, D) have different concentrations of trace elements, and the concentrations of trace elements are also different in pyrite of low-temperature hydrothermal origin collected from different locations. The study shows that elemental concentration is rather uniform in a pyrite vein. There are many micron and submicron mosaic pyrites in a pyrite vein, which is enriched in some trace elements, such as As and Mo. The content of trace element in pyrite vein depends upon the content of mosaic pyrite and of trace elements in it. Many environmentally sensitive trace elements are mainly contained in the minerals in coal, and hence the physical coal cleaning techniques can remove minerals from coal and decrease the emissions of potentially hazardous trace elements. ?? 2002 Elsevier Science B.V. All rights reserved.

Optical polarizer material

DOEpatents

Ebbers, C.A.

1999-08-31

Several crystals have been identified which can be grown using standard single crystals growth techniques and which have a high birefringence. The identified crystals include Li.sub.2 CO.sub.3, LiNaCO.sub.3, LiKCO.sub.3, LiRbCO.sub.3 and LiCsCO.sub.3. The condition of high birefringence leads to their application as optical polarizer materials. In one embodiment of the invention, the crystal has the chemical formula LiK.sub.(1-w-x-y) Na.sub.(1-w-x-z) Rb.sub.(1-w-y-z) Cs.sub.(1-x-y-z) CO.sub.3, where w+x+y+z=1. In another embodiment, the crystalline material may be selected from a an alkali metal carbonate and a double salt of alkali metal carbonates, where the polarizer has a Wollaston configuration, a Glan-Thompson configuration or a Glan-Taylor configuration. A method of making an LiNaCO.sub.3 optical polarizer is described. A similar method is shown for making an LiKCO.sub.3 optical polarizer.

The spectroscopic (FT-IR, FT-Raman and 1H, 13C NMR) and theoretical studies of cinnamic acid and alkali metal cinnamates

NASA Astrophysics Data System (ADS)

Kalinowska, Monika; Świsłocka, Renata; Lewandowski, Włodzimierz

2007-05-01

The effect of alkali metals (Li → Na → K → Rb → Cs) on the electronic structure of cinnamic acid (phenylacrylic acid) was studied. In this research many miscellaneous analytical methods, which complement one another, were used: infrared (FT-IR), Raman (FT-Raman), nuclear magnetic resonance ( 1H, 13C NMR) and quantum mechanical calculations. The spectroscopic studies lead to conclusions concerning the distribution of the electronic charge in molecule, the delocalization energy of π-electrons and the reactivity of metal complexes. The change of metal along with the series: Li → Na → K → Rb → Cs caused: (1) the change of electronic charge distribution in cinnamate anion what is seen via the occurrence of the systematic shifts of several bands in the experimental and theoretical IR and Raman spectra of cinnamates, (2) systematic chemical shifts for protons 1H and 13C nuclei.

Investigation of pump-to-seed beam matching on output features of Rb and Cs vapor laser amplifiers

NASA Astrophysics Data System (ADS)

Shen, Binglin; Huang, Jinghua; Xu, Xingqi; Xia, Chunsheng; Pan, Bailiang

2018-05-01

Taking into account the beam radii of pump light and seed laser along the entire length of the cell and their intensities in the cross section, a physical model with ordinary differential equation methods for alkali vapor amplifiers is established. Applied to the reported optically pumped Rb and diode-pumped Cs vapor amplifiers, the model shows good agreement between the calculated and measured dependence of amplified power on the seed power. A larger width of the spontaneous emission region as compared to the widths of pump absorption and laser emission regions, which will result in very high energy losses, is observed in the cell. Influence of pump and seed beam waists on output performance is calculated, showing that the pump and seed beam should match each other not only in shape but also in size, thus an optimal combination of beam radii is very important for efficient operation of alkali vapor amplifiers.

A2TiF 5· nH 2O ( A=K, Rb, or Cs; n=0 or 1): Synthesis, structure, characterization, and calculations of three new uni-dimensional titanium fluorides

NASA Astrophysics Data System (ADS)

Jo, Vinna; Woo Lee, Dong; Koo, Hyun-Joo; Ok, Kang Min

2011-04-01

Three new uni-dimensional alkali metal titanium fluoride materials, A2TiF 5· nH 2O ( A=K, Rb, or Cs; n=0 or 1) have been synthesized by hydrothermal reactions. The structures of A2TiF 5· nH 2O have been determined by single-crystal X-ray diffraction. The Ti 4+ cations have been reduced to Ti 3+ during the synthesis reactions. All three A2TiF 5· nH 2O materials contain novel 1-D chain structures that are composed of the slightly distorted Ti 3+F 6 corner-sharing octahedra attributable to the Jahn-Teller distortion. The coordination environment of the alkali metal cations plays an important role to determine the degree of turning in the chain structures. Complete structural analyses, Infrared and UV-vis diffuse reflectance spectra, and thermal analyses are presented, as are electronic structure calculations.

Optical polarizer material

DOEpatents

Ebbers, Christopher A.

1999-01-01

Several crystals have been identified which can be grown using standard single crystals growth techniques and which have a high birefringence. The identified crystals include Li.sub.2 CO.sub.3, LiNaCO.sub.3, LiKCO.sub.3, LiRbCO.sub.3 and LiCsCO.sub.3. The condition of high birefringence leads to their application as optical polarizer materials. In one embodiment of the invention, the crystal has the chemical formula LiK.sub.(1-w-x-y) Na.sub.(1-w-x-z) Rb.sub.(1-w-y-z) Cs.sub.(1-x-y-z) CO.sub.3, where w+x+y+z=1. In another embodiment, the crystalline material may be selected from a an alkali metal carbonate and a double salt of alkali metal carbonates, where the polarizer has a Wollaston configuration, a Glan-Thompson configuration or a Glan-Taylor configuration. A method of making an LiNaCO.sub.3 optical polarizer is described. A similar method is shown for making an LiKCO.sub.3 optical polarizer.

First-principles study of Cs/Rb co-doped FAPbI3 stability and degradation in the presence of water and oxygen

NASA Astrophysics Data System (ADS)

Guo, Yao; Li, Chengbo; Xue, Yuanbin; Geng, Cuihuan; Tian, Dayong

2018-02-01

The poor stability of organometallic halide perovskite in humid environments is one of the biggest challenges for its commercialization in light harvesting and electroluminescent displays. Understanding the atomic detail of the perovskite/water (oxygen) interface is a critical way to explore the practicability of perovskite. In this work, we report a density functional study of water and oxygen adsorption on the Cs/Rb incorporated FAPbI3 (001) surface. The role played by water and oxygen molecules has been extensively studied in the initial degradation processes, where the strong interactions between adsorbates and perovskite surfaces are confirmed. Our results show that the dopant-terminated surface was relatively more stable than PbI2-termination one. The effects of doping on the optoelectronic properties were slight at low concentrations. The calculations showed that the molecule tend to adsorb on the I-top site of the Cs-terminated surface and the Pb-top site of the PbI2 (Cs)-terminated surface. The vdW contribution on the bonding between bare surface and molecule can be observed. The degradation-induced optical absorption decrease in the visible region could be found. Water and oxygen molecule destroy the perovskite surface structures and subsequently reduce its conversion efficiency. These findings contribute molecular-level insight into the initial stage of perovskite degradation, which should be helpful to inspire new interfacial modifications to improve the stability of corresponding perovskite materials under wet conditions.

Gating current studies reveal both intra- and extracellular cation modulation of K+ channel deactivation

PubMed Central

Wang, Zhuren; Zhang, Xue; Fedida, David

1999-01-01

The presence of permeant ions can modulate the rate of gating charge return in wild-type human heart K+ (hKv1.5) channels. Here we employ gating current measurements in a non-conducting mutant, W472F, of the hKv1.5 channel to investigate how different cations can modulate charge return and whether the actions can be specifically localized at the internal as well as the external mouth of the channel pore. Intracellular cations were effective at accelerating charge return in the sequence Cs+ > Rb+ > K+ > Na+ > NMG+. Extracellular cations accelerated charge return with the selectivity sequence Cs+ > Rb+ > Na+ = NMG+. Intracellular and extracellular cation actions were of relatively low affinity. The Kd for preventing slowing of the time constant of the off-gating current decay (τoff) was 20.2 mM for intracellular Cs+ (Csi+) and 358 mM for extracellular Cs+ (Cso+). Both intracellular and extracellular cations can regulate the rate of charge return during deactivation of hKv1.5, but intracellular cations are more effective. We suggest that ion crystal radius is an important determinant of this action, with larger ions preventing slowing more effectively. Important parallels exist with cation-dependent modulation of slow inactivation of ionic currents in this channel. However, further experiments are required to understand the exact relationship between acceleration of charge return and the slowing of inactivation of ionic currents by cations. PMID:10050001

Optimization of radioactive sources to achieve the highest precision in three-phase flow meters using Jaya algorithm.

PubMed

Roshani, G H; Karami, A; Khazaei, A; Olfateh, A; Nazemi, E; Omidi, M

2018-05-17

Gamma ray source has very important role in precision of multi-phase flow metering. In this study, different combination of gamma ray sources (( 133 Ba- 137 Cs), ( 133 Ba- 60 Co), ( 241 Am- 137 Cs), ( 241 Am- 60 Co), ( 133 Ba- 241 Am) and ( 60 Co- 137 Cs)) were investigated in order to optimize the three-phase flow meter. Three phases were water, oil and gas and the regime was considered annular. The required data was numerically generated using MCNP-X code which is a Monte-Carlo code. Indeed, the present study devotes to forecast the volume fractions in the annular three-phase flow, based on a multi energy metering system including various radiation sources and also one NaI detector, using a hybrid model of artificial neural network and Jaya Optimization algorithm. Since the summation of volume fractions is constant, a constraint modeling problem exists, meaning that the hybrid model must forecast only two volume fractions. Six hybrid models associated with the number of used radiation sources are designed. The models are employed to forecast the gas and water volume fractions. The next step is to train the hybrid models based on numerically obtained data. The results show that, the best forecast results are obtained for the gas and water volume fractions of the system including the ( 241 Am- 137 Cs) as the radiation source. Copyright © 2018 Elsevier Ltd. All rights reserved.

β decay studies of n-rich Cs isotopes with the ISOLDE Decay Station

NASA Astrophysics Data System (ADS)

Lică, R.; Benzoni, G.; Morales, A. I.; Borge, M. J. G.; Fraile, L. M.; Mach, H.; Madurga, M.; Sotty, C.; Vedia, V.; De Witte, H.; Benito, J.; Berry, T.; Blasi, N.; Bracco, A.; Camera, F.; Ceruti, S.; Charviakova, V.; Cieplicka-Oryńczak, N.; Costache, C.; Crespi, F. C. L.; Creswell, J.; Fernández-Martínez, G.; Fynbo, H.; Greenlees, P.; Homm, I.; Huyse, M.; Jolie, J.; Karayonchev, V.; Köster, U.; Konki, J.; Kröll, T.; Kurcewicz, J.; Kurtukian-Nieto, T.; Lazarus, I.; Leoni, S.; Lund, M.; Marginean, N.; Marginean, R.; Mihai, C.; Mihai, R.; Negret, A.; Orduz, A.; Patyk, Z.; Pascu, S.; Pucknell, V.; Rahkila, P.; Regis, J. M.; Rotaru, F.; Saed-Sami, N.; Sánchez-Tembleque, V.; Stanoiu, M.; Tengblad, O.; Thuerauf, M.; Turturica, A.; Van Duppen, P.; Warr, N.

2017-05-01

Neutron-rich Ba isotopes are expected to exhibit octupolar correlations, reaching their maximum in isotopes around mass A = 146. The odd-A neutron-rich members of this isotopic chain show typical patterns related to non-axially symmetric shapes, which are however less marked compared to even-A ones, pointing to a major contribution from vibrations. In the present paper we present results from a recent study focused on 148-150Cs β-decay performed at the ISOLDE Decay Station equipped with fast-timing detectors. A detailed analysis of the measured decay half-lives and decay scheme of 149Ba is presented, giving a first insight in the structure of this neutron-rich nucleus.

Adsorption of radionuclides on the monolayer MoS2

NASA Astrophysics Data System (ADS)

Zhao, Qiang; Zhang, Zheng; Ouyang, Xiaoping

2018-04-01

How to remove radionuclides from radioactive wastewater has long been a difficult problem, especially in nuclear accidents. In this paper, the adsorption of radionuclides Cs, Sr, and Ba on the monolayer MoS2 was investigated by using the first principles calculation method. Through the calculation of adsorption energy and Hirshfeld charge of the radionuclides on the monolayer MoS2 at six adsorption sites, the results show that all of the radionuclides chemisorbed on the monolayer MoS2, and the adsorption strength of these three kinds of radionuclides on the monolayer MoS2 is Ba > Sr > Cs. This work might shed some light on the treatment of the radioactive wastewater.

From {sub {infinity}}{sup 1}[(UO{sub 2}){sub 2}O(MoO{sub 4}){sub 4}]{sup 6-} to {sub {infinity}}{sup 1}[(UO{sub 2}){sub 2}(MoO{sub 4}){sub 3}(MoO{sub 5})]{sup 6-} infinite chains in A{sub 6}U{sub 2}Mo{sub 4}O{sub 21} (A=Na, K, Rb, Cs) compounds: Synthesis and crystal structure of Cs{sub 6}[(UO{sub 2}){sub 2}(MoO{sub 4}){sub 3}(MoO{sub 5})

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

Yagoubi, S.; Groupe de Radiochimie, Institut de Physique Nucleaire d'Orsay, Universite Paris-Sud XI, 91406 Orsay Cedex; Obbade, S., E-mail: said.obbade@phelma.grenoble-inp.f

2011-05-15

A new caesium uranyl molybdate belonging to the M{sub 6}U{sub 2}Mo{sub 4}O{sub 21} family has been synthesized by solid-state reaction and its structure determined from single-crystal X-ray diffraction data. Contrary to the other alkali uranyl molybdates of this family (A=Na, K, Rb) where molybdenum atoms adopt only tetrahedral coordination and which can be formulated A{sub 6}[(UO{sub 2}){sub 2}O(MoO{sub 4}){sub 4}], the caesium compound Cs{sub 6}U{sub 2}Mo{sub 4}O{sub 21} should be written Cs{sub 6}[(UO{sub 2}){sub 2}(MoO{sub 4}){sub 3}(MoO{sub 5})] with molybdenum atoms in tetrahedral and square pyramidal environments. Cs{sub 6}[(UO{sub 2}){sub 2}(MoO{sub 4}){sub 3}(MoO{sub 5})] crystallizes in the triclinic symmetry withmore » space group P1-bar and a=10.4275(14) A, b=15.075(2) A, c=17.806(2) A, {alpha}=70.72(1){sup o}, {beta}=80.38(1){sup o} and {gamma}=86.39(1){sup o}, V=2604.7(6) A{sup 3}, Z=4, {rho}{sub mes}=5.02(2) g/cm{sup 3} and {rho}{sub cal}=5.08(3) g/cm{sup 3}. A full-matrix least-squares refinement on the basis of F{sup 2} yielded R{sub 1}=0.0464 and wR{sub 2}=0.0950 for 596 parameters with 6964 independent reflections with I{>=}2{sigma}(I) collected on a BRUKER AXS diffractometer with Mo(K{alpha}) radiation and a CCD detector. The crystal structure of Cs compound is characterized by {sub {infinity}}{sup 1}[(UO{sub 2}){sub 2}(MoO{sub 4}){sub 3}(MoO{sub 5})]{sup 6-} parallels chains built from U{sub 2}O{sub 13} dimeric units, MoO{sub 4} tetrahedra and MoO{sub 5} square pyramids, whereas, Na, K and Rb compounds are characterized by {sub {infinity}}{sup 1}[(UO{sub 2}){sub 2}O(MoO{sub 4}){sub 4}]{sup 6-} parallel chains formulated simply of U{sub 2}O{sub 13} units and MoO{sub 4} tetrahedra. Infrared spectroscopy measurements using powdered samples synthesized by solid-state reaction, confirm the structural results. The thermal stability and the electrical conductivity are also studied. The four compounds decompose at low temperature (between 540 and 610 {sup o}C). -- Graphical abstract: The staking of {sub {infinity}}{sup 1}[(UO{sub 2}){sub 2}(MoO{sub 4}){sub 3}(MoO{sub 5})]{sup 6-} infinite uranyl molybdate ribbons in the Cs{sub 6}[(UO{sub 2}){sub 2}(MoO{sub 4}){sub 3}(MoO{sub 5})] structure. Display Omitted Highlights: {yields} Cs{sub 6}U{sub 2}Mo{sub 4}O{sub 2} a new compound with bidimensional crystal structure, characterized by infinite uranyl molybdate chains. {yields} Crystal structure similar to these of the compounds containing Na, K, Rb. {yields} Molybdenum atoms surrounded by five oxygen atoms to form an original and strongly distorted MoO{sub 5} environment. {yields} The chains arrangement illustrates the key role of the alkaline ionic radius, in the crystal structure distortion for Cs compound.« less

Extended Fourier-transform spectroscopy studies and deperturbation analysis of the spin-orbit coupled A{sup 1}Σ{sup +} and b{sup 3}Π states in RbCs

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

Kruzins, A.; Alps, K.; Docenko, O.

2014-11-14

The article presents a study of the strongly spin-orbit coupled singlet A{sup 1}Σ{sup +} and triplet b{sup 3}Π states of the RbCs molecule, which provide an efficient optical path to transfer ultracold molecules to their rovibrational ground state. Fourier-transform A{sup 1}Σ{sup +} − b{sup 3}Π → X{sup 1}Σ{sup +} and (4){sup 1}Σ{sup +} → A{sup 1}Σ{sup +} − b{sup 3}Π laser-induced fluorescence (LIF) spectra were recorded for the natural mixture of the {sup 85}Rb{sup 133}Cs and {sup 87}Rb{sup 133}Cs isotopologues produced in a heat pipe oven. Overall 8730 rovibronic term values of A{sup 1}Σ{sup +} and b{sup 3}Π states weremore » determined with an uncertainty of 0.01 cm{sup −1} in the energy range [9012, 14087] cm{sup −1}, covering rotational quantum numbers J ∈ [6, 324]. An energy-based deperturbation analysis performed in the framework of the four A{sup 1}Σ{sup +} − b{sup 3}Π{sub Ω=0,1,2} coupled-channels approach reproduces 97% of the experimental term values of both isotopologues with a standard deviation of 0.0036 cm{sup −1}. The reliability of the deperturbed mass-invariant potentials and spin-orbit coupling functions of the interacting A{sup 1}Σ{sup +} and b{sup 3}Π states is additionally proved by a good reproduction of the A − b → X and (4){sup 1}Σ{sup +} → A − b relative intensity distributions. The achieved accuracy of the A − b complex description allowed us to use the latter to assign the observed (5){sup 1}Σ{sup +} → A − b and (3){sup 1}Π → A − b transitions. As is demonstrated, LIF to the A − b complex becomes as informative as to the ground X{sup 1}Σ{sup +} state, which is confirmed by comparing the results of (4){sup 1}Σ{sup +} state analysis based on (4){sup 1}Σ{sup +} → A − b LIF with the data from V. Zuters et al. [Phys. Rev. A 87, 022504 (2013)] based on (4){sup 1}Σ{sup +} → X LIF.« less

Charge breeding results and future prospects with electron cyclotron resonance ion source and electron beam ion source (invited)

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

Vondrasek, R.; Levand, A.; Pardo, R.

2012-02-15

The Californium Rare Ion Breeder Upgrade (CARIBU) of the Argonne National Laboratory ATLAS facility will provide low-energy and reaccelerated neutron-rich radioactive beams for the nuclear physics program. A 70 mCi {sup 252}Cf source produces fission fragments which are thermalized and collected by a helium gas catcher into a low-energy particle beam with a charge of 1+ or 2+. An electron cyclotron resonance (ECR) ion source functions as a charge breeder in order to raise the ion charge sufficiently for acceleration in the ATLAS linac. The final CARIBU configuration will utilize a 1 Ci {sup 252}Cf source to produce radioactive beamsmore » with intensities up to 10{sup 6} ions/s for use in the ATLAS facility. The ECR charge breeder has been tested with stable beam injection and has achieved charge breeding efficiencies of 3.6% for {sup 23}Na{sup 8+}, 15.6% for {sup 84}Kr{sup 17+}, and 13.7% for {sup 85}Rb{sup 19+} with typical breeding times of 10 ms/charge state. For the first radioactive beams, a charge breeding efficiency of 11.7% has been achieved for {sup 143}Cs{sup 27+} and 14.7% for {sup 143}Ba{sup 27+}. The project has been commissioned with a radioactive beam of {sup 143}Ba{sup 27+} accelerated to 6.1 MeV/u. In order to take advantage of its lower residual contamination, an EBIS charge breeder will replace the ECR charge breeder in the next two years. The advantages and disadvantages of the two techniques are compared taking into account the requirements of the next generation radioactive beam facilities.« less

Determination of major elements by wavelength-dispersive X-ray fluorescence spectrometry and trace elements by inductively coupled plasma mass spectrometry in igneous rocks from the same fused sample (110 mg)

NASA Astrophysics Data System (ADS)

Amosova, Alena A.; Panteeva, Svetlana V.; Chubarov, Victor M.; Finkelshtein, Alexandr L.

2016-08-01

The fusion technique is proposed for simultaneous determination of 35 elements from the same sample. Only 110 mg of rock sample was used to obtain fused glasses for quantitative determination of 10 major elements by wavelength dispersive X-ray fluorescence analysis, 16 rare earth elements and some other trace elements by inductively coupled plasma mass spectrometry analysis. Fusion was performed with 1.1 g of lithium metaborate and LiBr solution as the releasing agent in platinum crucible in electric furnace at 1100 °C. The certified reference materials of ultramafic, mafic, intermediate and felsic igneous rocks have been applied to obtain the calibration curves for rock-forming oxides (Na2O, MgO, Al2O3, SiO2, P2O5, K2O, CaO, TiO2, MnO, Fe2O3) and some trace elements (Ba, Sr, Zr) determination by X-ray fluorescence analysis. The repeatability does not exceed the allowable standard deviation for a wide range of concentrations. In the most cases the relative standard deviation was less than 5%. Obtained glasses were utilized for the further determination of rare earth (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) and some other (Ba, Sr, Zr, Rb, Cs, Y, Nb, Hf, Ta, Th and U) trace elements by inductively coupled plasma mass spectrometry analysis with the same certified reference materials employed. The results could mostly be accepted as satisfactory. The proposed procedure essentially reduces the expenses in comparison with separate sample preparation for inductively coupled plasma mass spectrometry and X-ray fluorescence analysis.

Uniformity and diversity in the composition of mineralizing fluids from hydrothermal vents on the southern Juan de Fuca Ridge.

USGS Publications Warehouse

Philpotts, J.A.; Aruscavage, P. J.; Von Damm, Karen L.

1987-01-01

Abundances of Li, Na, K, Rb, Ca, Sr, Ba, Mn, Fe, Zn, and Si have been determined in fluid samples from 7 vents located in three areas on the southern Juan de Fuca Ridge. The hydrothermal component estimated from the Mg contents of the samples ranges from 7% to 76%. Concentrations of Fe and Si, among other elements, in acid-stabilized solutions appear to be generally representative of the parental hydrothermal fluids, but some Zn determinations and most Ba values appear to be too low.-from Authors

New Tests for Variations of the Fine Structure Constant

NASA Technical Reports Server (NTRS)

Prestage, John D.

1995-01-01

We describe a new test for possible variations of the fine structure constant, by comparisons of rates between clocks based on hyperfine transitions in alkali atomos with different atomic number Z. H- maser, Cs and Hg+ clocks have a different dependence on ia relativistic contributions of order (Z. Recent H-maser vs Hg+ clock comparison data improves laboratory limits on a time variation by 100-fold to giveFuture laser cooled clocks (Be+, Rb, Cs, Hg+, etc.), when compared, will yield the most senstive of all tests for.

Direct evidence for a pressure-induced nodal superconducting gap in the Ba0.65Rb0.35Fe2As2 superconductor

PubMed Central

Guguchia, Z.; Amato, A.; Kang, J.; Luetkens, H.; Biswas, P. K.; Prando, G.; von Rohr, F.; Bukowski, Z.; Shengelaya, A.; Keller, H.; Morenzoni, E.; Fernandes, Rafael M.; Khasanov, R.

2015-01-01

The superconducting gap structure in iron-based high-temperature superconductors (Fe-HTSs) is non-universal. In contrast to other unconventional superconductors, in the Fe-HTSs both d-wave and extended s-wave pairing symmetries are close in energy. Probing the proximity between these very different superconducting states and identifying experimental parameters that can tune them is of central interest. Here we report high-pressure muon spin rotation experiments on the temperature-dependent magnetic penetration depth in the optimally doped nodeless s-wave Fe-HTS Ba0.65Rb0.35Fe2As2. Upon pressure, a strong decrease of the penetration depth in the zero-temperature limit is observed, while the superconducting transition temperature remains nearly constant. More importantly, the low-temperature behaviour of the inverse-squared magnetic penetration depth, which is a direct measure of the superfluid density, changes qualitatively from an exponential saturation at zero pressure to a linear-in-temperature behaviour at higher pressures, indicating that hydrostatic pressure promotes the appearance of nodes in the superconducting gap. PMID:26548650

Direct evidence for a pressure-induced nodal superconducting gap in the Ba 0.65Rb 0.35Fe 2As 2 superconductor

DOE PAGES

Guguchia, Z.; Amato, A.; Kang, J.; ...

2015-11-09

The superconducting gap structure in iron-based high-temperature superconductors (Fe-HTSs) is non-universal. Contrasting with other unconventional superconductors, in the Fe-HTSs both d-wave and extended s-wave pairing symmetries are close in energy. Probing the proximity between these very different superconducting states and identifying experimental parameters that can tune them is of central interest. Here we report high-pressure muon spin rotation experiments on the temperature-dependent magnetic penetration depth in the optimally doped nodeless s-wave Fe-HTS Ba 0.65Rb 0.35Fe 2As 2. Upon pressure, a strong decrease of the penetration depth in the zero-temperature limit is observed, while the superconducting transition temperature remains nearly constant.more » More importantly, the low-temperature behaviour of the inverse-squared magnetic penetration depth, which is a direct measure of the superfluid density, changes qualitatively from an exponential saturation at zero pressure to a linear-in-temperature behaviour at higher pressures, indicating that hydrostatic pressure promotes the appearance of nodes in the superconducting gap.« less

Collisional Cooling of Light Ions by Cotrapped Heavy Atoms.

PubMed

Dutta, Sourav; Sawant, Rahul; Rangwala, S A

2017-03-17

We experimentally demonstrate cooling of trapped ions by collisions with cotrapped, higher-mass neutral atoms. It is shown that the lighter ^{39}K^{+} ions, created by ionizing ^{39}K atoms in a magneto-optical trap (MOT), when trapped in an ion trap and subsequently allowed to cool by collisions with ultracold, heavier ^{85}Rb atoms in a MOT, exhibit a longer trap lifetime than without the localized ^{85}Rb MOT atoms. A similar cooling of trapped ^{85}Rb^{+} ions by ultracold ^{133}Cs atoms in a MOT is also demonstrated in a different experimental configuration to validate this mechanism of ion cooling by localized and centered ultracold neutral atoms. Our results suggest that the cooling of ions by localized cold atoms holds for any mass ratio, thereby enabling studies on a wider class of atom-ion systems irrespective of their masses.

Role of an inward rectifier K+ current and of hyperpolarization in human myoblast fusion

PubMed Central

Liu, J-H; Bijlenga, P; Fischer-Lougheed, J; Occhiodoro, T; Kaelin, A; Bader, C R; Bernheim, L

1998-01-01

The role of K+ channels and membrane potential in myoblast fusion was evaluated by examining resting membrane potential and timing of expression of K+ currents at three stages of differentiation of human myogenic cells: undifferentiated myoblasts, fusion-competent myoblasts (FCMBs), and freshly formed myotubes. Two K+ currents contribute to a hyperpolarization of myoblasts prior to fusion: IK(NI), a non-inactivating delayed rectifier, and IK(IR), an inward rectifier. IK(NI) density is low in undifferentiated myoblasts, increases in FCMBs and declines in myotubes. On the other hand, IK(IR) is expressed in 28 % of the FCMBs and in all myotubes. IK(IR) is reversibly blocked by Ba2+ or Cs+. Cells expressing IK(IR) have resting membrane potentials of −65 mV. A block by Ba2+ or Cs+ induces a depolarization to a voltage determined by IK(NI) (−32 mV). Cs+ and Ba2+ ions reduce myoblast fusion. It is hypothesized that the IK(IR)-mediated hyperpolarization allows FCMBs to recruit Na+, K+ and T-type Ca2+ channels which are present in these cells and would otherwise be inactivated. FCMBs, rendered thereby capable of firing action potentials, could amplify depolarizing signals and may accelerate fusion. PMID:9705997

Soft-hard acid-base interactions: probing coordination preferences of sulfur an selenium in mixed chalcophosphates in the family APbPS{sub 4-x}Se{sub x} (A = K, Rb, cs; x = 0-4).

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

Rothenberger, A.; Morris, C.; Wang, H. H.

2009-01-01

The synthesis and structures of the three new compounds, KPbPS{sub 1.84}Se{sub 2.16} (1), RbPbPS{sub 1.56}Se{sub 2.43} (2), and CsPbPS{sub 3.46}Se{sub 0.54} (3), are reported. The solid state structures of 1-3 consist of two-dimensional layers of [PbP(S/Se){sub 4}] separated by alkali metal ions. The structure of 1 was solved in the orthorhombic space group Pna2{sub 1}. Compounds 2 and 3 possess the CsSmGeS{sub 4} structure type, crystallizing in the orthorhombic space group P2{sub 1}2{sub 1}2{sub 1}. All compounds were refined as racemic twins. All chalcogen sites around the tetrahedrally coordinated P atoms show mixed S/Se occupancy; however, there is a preferencemore » for Se binding to Pb ions and S binding to alkali ions. A {sup 31}P magic angle spinning NMR study on 1 suggests that, in mixed seleno-/thiophosphates, all of the anions [PS{sub x}Se{sub 4-x}]{sup 3-} (x = 0, 1, 2, 3, 4) are present. The different amount of sulfur and selenium present in KPbPS{sub 1.84}Se{sub 2.16} (1), RbPbPS{sub 1.56}Se{sub 2.43} (2), and CsPbPS{sub 3.46}Se{sub 0.54} (3) is reflected in the solid state absorption spectra from which bandgaps of 2.2 eV were determined for 1 and 2, and a blue-shift to 2.5 eV was observed because of the higher sulfur-content in 3. Thermogravimetric analysis experiments indicated that, upon heating, compound 1 decomposes forming PbSe and sulfur together with other unidentified products. A Raman spectrum of compound 1 showed more bands than are usually observed in seleno- or thiophosphate salts and is another indicator of the mixed seleno-/thiophosphate anions found in 1.« less

Relative contribution of AtHAK5 and AtAKT1 to K+ uptake in the high-affinity range of concentrations.

PubMed

Rubio, Francisco; Nieves-Cordones, Manuel; Alemán, Fernando; Martínez, Vicente

2008-12-01

The relative contribution of the high-affinity K(+) transporter AtHAK5 and the inward rectifier K(+) channel AtAKT1 to K(+) uptake in the high-affinity range of concentrations was studied in Arabidopsis thaliana ecotype Columbia (Col-0). The results obtained with wild-type lines, with T-DNA insertion in both genes and specific uptake inhibitors, show that AtHAK5 and AtAKT1 mediate the NH4+-sensitive and the Ba(2+)-sensitive components of uptake, respectively, and that they are the two major contributors to uptake in the high-affinity range of Rb(+) concentrations. Using Rb(+) as a K(+) analogue, it was shown that AtHAK5 mediates absorption at lower Rb(+) concentrations than AtAKT1 and depletes external Rb(+) to values around 1 muM. Factors such as the presence of K(+) or NH4+ during plant growth determine the relative contribution of each system. The presence of NH4+ in the growth solution inhibits the induction of AtHAK5 by K(+) starvation. In K(+)-starved plants grown without NH4+, both systems are operative, but when NH4+ is present in the growth solution, AtAKT1 is probably the only system mediating Rb(+) absorption, and the capacity of the roots to deplete Rb(+) is reduced.

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

Karayigit, A.I.; Bulut, Y.; Karayigit, G.

A total of 48 samples, feed coals (FCs), fly ashes (FAs) and bottom ashes (BAs), which were systematically collected once a week over an eight-week period from boiler units, B1-4 with 660 MW and B5-6 with 330 MW capacity from Soma power plant, have been evaluated for major and trace elements (Al, Ca, Fe, K, Mg, Mn, Na, Ti, S, As, B, Ba, Be, Bi, Cd, Co, Cr, Cu, Cs, Ga, Ge, Hf, Hg, Li, Mo, Nb, Ni, P, Pb, Rb, Sb, Sc, Se, Sn, Sr, Ta, Th, Tl, U, V, Y, Zn, Zr, and REEs) to get information onmore » behavior during coal combustion. This study indicates that some elements such as Hg, Bi, Cd, As, Pb, Ge, Tl, Sn, Zn, Sb, B show enrichments in FAs relative to the BAs in both group boiler units. In addition to these, Cs, Lu, Tm, and Ga in Units B1-4 and S in Units B5-6 also have enrichments in FAs. Elements showing enrichments in BAs in both group boiler units are Ta, Mn, Nb. In addition to these, Se, Ca, Mg, Na, Fe in Units B1-4 and Cu in Units B5-6 also have enrichments in BAs. The remaining elements investigated in this study have no clear segregation between FAs and BAs. Mass balance calculations with the two methods show that some elements, S, Ta, Hg, Se, Zn, Na, Ca in Units B1-4, and Hg, S, Ta, Se, P in Units B5-6, have volatile behavior during coal combustion in the Soma power plant. This study also implies that some elements, Sb and Tb in Units B1-4 and Sb in Units B5-6, have relatively high retention effects in the combustion residues from the Soma power plant.« less

Geochemical evidence for a complex origin for the Kelso dunes, Mojave National Preserve, California USA

USGS Publications Warehouse

Muhs, Daniel; Lancaster, Nicholas; Skipp, Gary L.

2017-01-01

The Kelso Dune field in southern California is intriguing because although it is of limited areal extent (~ 100 km2), it has a wide variety of dune forms and contains many active dunes (~ 40 km2), which is unusual in the Mojave Desert. Studies over the past eight decades have concluded that the dunes are derived primarily from a single source, Mojave River alluvium, under a dominant, westerly-to-northwesterly wind regime. The majority of these studies did not, however, present data to support the Mojave River as the only source. We conducted mineralogical and geochemical studies of most of the 14 geomorphically defined dune groups of the Kelso Dune field as well as potential sand sources, alluvial sediments from the surrounding mountain ranges. Results indicate that sands in the nine western dune groups have K/Rb and K/Ba (primarily from K-feldspar) compositions that are indistinguishable from Mojave River alluvium (westerly/northwesterly winds) and Budweiser Wash alluvium (southwesterly winds), permitting an interpretation of two sources. In contrast, sands from the five eastern dune groups have K/Rb and K/Ba values that indicate significant inputs from alluvial fan deposits of the Providence Mountains. This requires either rare winds from the east or southeast or, more likely, aeolian reworking of distal Providence Mountain fan sediments by winds from the west, at a rate greater than input from the Mojave River or other western sources. The results indicate that even a small dune field can have a complex origin, either from seasonally varying winds or complex alluvial-fan-dune interaction. Application of K/Rb and K/Ba in K-feldspar as a provenance indicator could be used in many of the world's ergs or sand seas, where dune origins are still not well understood or are controversial. Four examples are given from Africa and the Middle East where such an approach could yield useful new information about dune sand provenance.

A complex origin for the Kelso Dunes, Mojave National Preserve, California, USA: A case study using a simple geochemical method with global applications

NASA Astrophysics Data System (ADS)

Muhs, Daniel R.; Lancaster, Nicholas; Skipp, Gary L.

2017-01-01

The Kelso Dune field in southern California is intriguing because although it is of limited areal extent ( 100 km2), it has a wide variety of dune forms and contains many active dunes ( 40 km2), which is unusual in the Mojave Desert. Studies over the past eight decades have concluded that the dunes are derived primarily from a single source, Mojave River alluvium, under a dominant, westerly-to-northwesterly wind regime. The majority of these studies did not, however, present data to support the Mojave River as the only source. We conducted mineralogical and geochemical studies of most of the 14 geomorphically defined dune groups of the Kelso Dune field as well as potential sand sources, alluvial sediments from the surrounding mountain ranges. Results indicate that sands in the nine western dune groups have K/Rb and K/Ba (primarily from K-feldspar) compositions that are indistinguishable from Mojave River alluvium (westerly/northwesterly winds) and Budweiser Wash alluvium (southwesterly winds), permitting an interpretation of two sources. In contrast, sands from the five eastern dune groups have K/Rb and K/Ba values that indicate significant inputs from alluvial fan deposits of the Providence Mountains. This requires either rare winds from the east or southeast or, more likely, aeolian reworking of distal Providence Mountain fan sediments by winds from the west, at a rate greater than input from the Mojave River or other western sources. The results indicate that even a small dune field can have a complex origin, either from seasonally varying winds or complex alluvial-fan-dune interaction. Application of K/Rb and K/Ba in K-feldspar as a provenance indicator could be used in many of the world's ergs or sand seas, where dune origins are still not well understood or are controversial. Four examples are given from Africa and the Middle East where such an approach could yield useful new information about dune sand provenance.

Geochemical Evidence for Mantle Enrichment and Lower Crustal Assimilation in Orogenic Volcanics from Monte Arcuentu, Southern Sardinia: Implications for Geodynamics and Evolution of the Western Mediterranean

NASA Astrophysics Data System (ADS)

Vero, S.; Kempton, P. D.; Downes, H.

2016-12-01

Miocene (ca. 18Ma) subduction-related basalts and basaltic andesites from Monte Arcuentu (MA), southern Sardinia, show a remarkable correlation between SiO2 and 87Sr/86Sr (up to 0.711) that contrasts with most other orogenic volcanics worldwide. MgO ranges from 13.4 - 2.4 wt%, yet the rocks form a baseline trend at low SiO2 (51-56 wt%) from which other arcs diverge toward high SiO2. In contrast, MA exhibits a steep trend that extends toward the field of lithosphere-derived, lamproites from central Italy. New high-precision Pb and Hf isotope data help to constrain the petrogenesis of these rocks. The most primitive MA rocks (MgO > 8.5wt%) were derived from a mantle wedge metasomatized by melts derived from terrigenous sediment, likely derived from Archean terranes of N Africa. This metasomatized source had high 87Sr/86Sr (O.705-0.709) and 7/4Pb (15.65 - 15.67) with low ɛHf (-1 to +8) and ɛNd (+1 to -6), but does not account for the full range of isotopic compositions observed. More evolved rocks (MgO < 8.5 wt%) have higher 87Sr/86Sr (0.711) and 7/4Pb (15.68), lower ɛHf (-8) and ɛNd (-9). However, one group of evolved rocks with low Rb/Ba trends toward low 6/4Pb whereas another group with high Rb/Ba extends to high 6/4Pb. Mixing calculations suggest that evolved rocks with low Rb/Ba - low 6/4Pb interacted with Hercynian-type lower crust. High Rb/Ba - high 6/4Pb rocks may have interacted with lithospheric mantle similar to that sampled by Italian lamproites, but upper crustal contamination cannot be ruled out. Partial melting of these normally refractory lithologies was facilitated by the rapid extension, and subsequent mantle upwelling, that occurred as Sardinia rifted and rotated away from the European plate during the Miocene (32-15 Ma). High rates of melt accumulation and high melt fractions ponded near the MOHO, creating a "hot zone", enabling mafic crustal melting. Fractional crystallization under these PT conditions involved olivine + cpx with little or no plag, such that differentiation proceeded without significant increase in SiO2. High rates of extension may also have facilitated rapid ascent of magmas to the surface with minimal interaction with mid- to upper crust. The MA rocks provide insights into lower crustal assimilation process that may be obscured by upper crustal AFC processes in other suites.

First-Principles Prediction of New Electrides with Nontrivial Band Topology Based on One-Dimensional Building Blocks

NASA Astrophysics Data System (ADS)

Park, Changwon; Kim, Sung Wng; Yoon, Mina

2018-01-01

We introduce a new class of electrides with nontrivial band topology by coupling materials database searches and first-principles-calculations-based analysis. Cs3O and Ba3N are for the first time identified as a new class of electrides, consisting of one-dimensional (1D) nanorod building blocks. Their crystal structures mimic β -TiCl3 with the position of anions and cations exchanged. Unlike the weakly coupled nanorods of β -TiCl3 , Cs3O and Ba3N retain 1D anionic electrons along the hollow interrod sites; additionally, a strong interrod interaction in C3O and Ba3N induces band inversion in a 2D superatomic triangular lattice, resulting in Dirac-node lines. The new class of electrides can serve as a prototype for new electrides with a large cavity space that can be utilized for various applications such as gas storage, ion transport, and metal intercalation.

Pan-African alkali granites and syenites of Kerala as imprints of taphrogenic magmatism in the South Indian shield

NASA Technical Reports Server (NTRS)

Santosh, M.; Drury, S. A.; Iyer, S. S.

1988-01-01

Granite and syenite plutons with alkaline affinities ranging in age from 550 to 750 Ma sporadically puncture the Precambrian granulites of the Kerala region. All the bodies are small (20 to 60 sq km), E-W to NW-SE elongated elliptical intrusives with sharp contacts and lie on or close to major late Proterozoic lineaments. Geochemical plots of A-F-M and An-Ab-Or relations show an apparent alkali enrichment trend on the former, but the plutons define relatively distinct fields on the latter. Most of the plutons are adamellitic to granitic by chemistry. The variations of SiO2 with log sub 10 K2O/MgO (1) brings out the distinct alkaline nature of the plutons. Some of the granites are extremely potassic, like the Peralimala pluton, which shows up to 11.8 percent K2O. On a SiO2-Al2O3-Na2O+K2O (mol percent) plot, the plutons vary from peraluminous to peralkaline, but none are nepheline normative. Low MgO, low to moderate CaO and high Fe2O3/FeO values are other common characteristics. Among trace elements, depletion of Ba, Sr and Rb with high K/Ba and K/Rb values are typical. Overall, the plutons show a trend of decreasing K/Rb ratio with increasing K content. Individual plutons show more clearly defined trends similar to those from granitic masses characterized by plagioclase fractionation.

Effect of Wood Aging on Wine Mineral Composition and 87Sr/86Sr Isotopic Ratio.

PubMed

Kaya, Ayse D; Bruno de Sousa, Raúl; Curvelo-Garcia, António S; Ricardo-da-Silva, Jorge M; Catarino, Sofia

2017-06-14

The evolution of mineral composition and wine strontium isotopic ratio 87 Sr/ 86 Sr (Sr IR) during wood aging were investigated. A red wine was aged in stainless steel tanks with French oak staves (Quercus sessiliflora Salisb.), with three industrial scale replicates. Sampling was carried out after 30, 60, and 90 days of aging, and the wines were evaluated in terms of general analysis, phenolic composition, total polysaccharides, multielement composition, and Sr IR. Li, Be, Mg, Al, Sc, Ti, V, Mn, Co, Ni, Cu, Zn, Ga, Ge, As, Rb, Sr, Y, Zr, Mo, Sb, Cs, Ba, Pr, Nd, Sm, Eu, Dy, Ho, Er, Yb, Lu, Tl, and Pb elements and 87 Sr/ 86 Sr were determined by quadrupole inductively coupled plasma mass spectrometry (Q-ICP-MS) and Na, K, Ca, and Fe by flame atomic absorption spectrometry (FAAS). Two-way ANOVA was applied to assess wood aging and time effect on Sr IR and mineral composition. Wood aging resulted in significantly higher concentrations of Mg, V, Co, Ni, and Sr. At the end of the aging period, wine exhibited statistically identical Sr IR compared to control. Study suggests that wood aging does not affect 87 Sr/ 86 Sr, not precluding the use of this parameter for wine traceability purposes.

Multivariate class modeling techniques applied to multielement analysis for the verification of the geographical origin of chili pepper.

PubMed

Naccarato, Attilio; Furia, Emilia; Sindona, Giovanni; Tagarelli, Antonio

2016-09-01

Four class-modeling techniques (soft independent modeling of class analogy (SIMCA), unequal dispersed classes (UNEQ), potential functions (PF), and multivariate range modeling (MRM)) were applied to multielement distribution to build chemometric models able to authenticate chili pepper samples grown in Calabria respect to those grown outside of Calabria. The multivariate techniques were applied by considering both all the variables (32 elements, Al, As, Ba, Ca, Cd, Ce, Co, Cr, Cs, Cu, Dy, Fe, Ga, La, Li, Mg, Mn, Na, Nd, Ni, Pb, Pr, Rb, Sc, Se, Sr, Tl, Tm, V, Y, Yb, Zn) and variables selected by means of stepwise linear discriminant analysis (S-LDA). In the first case, satisfactory and comparable results in terms of CV efficiency are obtained with the use of SIMCA and MRM (82.3 and 83.2% respectively), whereas MRM performs better than SIMCA in terms of forced model efficiency (96.5%). The selection of variables by S-LDA permitted to build models characterized, in general, by a higher efficiency. MRM provided again the best results for CV efficiency (87.7% with an effective balance of sensitivity and specificity) as well as forced model efficiency (96.5%). Copyright © 2016 Elsevier Ltd. All rights reserved.

Determination of the Extent of Trace Metals Pollution in Soils, Sediments and Human Hair at e-Waste Recycling Site in Ghana.

PubMed

Tokumaru, Takashi; Ozaki, Hirokazu; Onwona-Agyeman, Siaw; Ofosu-Anim, John; Watanabe, Izumi

2017-10-01

The concentrations of trace elements (Mg, Al, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, As, Se, Rb, Sr, Y, Mo, Cd, In, Sn, Sb, Cs, Ba, Tl, Pb, and Bi) in soils, sediment, human hair, and foodstuff collected around the electronic waste (e-waste) recycling sites in Accra, Ghana were detected using inductively coupled plasma-mass spectrometry (ICP-MS). High levels of Cu, Zn, Mo, Cd, In, Sn, Sb, and Pb were observed in soils collected from the e-waste recycling sites. Four sequential extraction procedures were used to evaluate the mobility and bioavailability of metals (Cu, Zn, Cd, Sb, and Pb). Especially, the results showed that Cd and Zn in soils were mostly recovered in exchangeable fraction (respectively 58.9 and 62.8%). Sediment collected from around the site had enrichment of Zn, Sn, Sb, Mo, In, Pb, and Bi. The concentrations of Cu, Mo, Cd, Sb, and Pb in human hair were significantly higher than those collected from the control site (p < 0.01). Additionally, hierarchical cluster analysis reviewed that these elements were derived from e-waste activities. The results of Pb isotopic ratios in the samples indicate that Pb in human hair possibly originated from contaminated soils, fish, and foodstuff.

Biogeochemical characteristics of Rosa canina grown in hydrothermally contaminated soils of the Gümüşhane Province, Northeast Turkey.

PubMed

Vural, Alaaddin

2015-08-01

Kırkpavli alteration area (Gümüşhane, Northeast Turkey) is contaminated by heavy metals such as Cd, Pb, As, Cu and Zn. The quantity of accumulation of heavy metal trace elements and macroelements in 32 leaves of Rosa canina of the Kırkpavli alteration area has been studied within the scope of geochemical studies. Element contents of samples were assessed using various parameters including descriptive statistics, factor analysis, correlation coefficients and bioaccumulation factor. Concentrations were detected in the acceptable range for Mo, Cu, Pb, Ni, As, Cd, Sb, P, Ti, Na, Se and Sn. Concentrations of Co, Mn, Ba and Hg were detected close to the acceptable values, whereas Zn, Fe, Sr, V, Ca, Cr, Mg, B, Al, K, W, Sc, Cs and Rb concentrations were detected above the acceptable values. Principal component analysis was used to identify the elements that have a close relationship with each other and/or similar origins. It has been concluded that Zn, Cu, As and Mo content of the plant were related to hydrothermal alteration process and they behaved together, whereas Mn and Fe were especially products of weathering conditions, also behaved together. In terms of macroelements, Ca, Mg and Na had similar behaviour, while P and K had the same correlation.

The structural diversity of ABS{sub 3} compounds with d{sup 0} electronic configuration for the B-cation

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

Brehm, John A., E-mail: brehmj@sas.upenn.edu; Bennett, Joseph W.; Schoenberg, Michael Rutenberg

2014-06-14

We use first-principles density functional theory within the local density approximation to ascertain the ground state structure of real and theoretical compounds with the formula ABS{sub 3} (A = K, Rb, Cs, Ca, Sr, Ba, Tl, Sn, Pb, and Bi; and B = Sc, Y, Ti, Zr, V, and Nb) under the constraint that B must have a d{sup 0} electronic configuration. Our findings indicate that none of these AB combinations prefer a perovskite ground state with corner-sharing BS{sub 6} octahedra, but that they prefer phases with either edge- or face-sharing motifs. Further, a simple two-dimensional structure field map createdmore » from A and B ionic radii provides a neat demarcation between combinations preferring face-sharing versus edge-sharing phases for most of these combinations. We then show that by modifying the common Goldschmidt tolerance factor with a multiplicative term based on the electronegativity difference between A and S, the demarcation between predicted edge-sharing and face-sharing ground state phases is enhanced. We also demonstrate that, by calculating the free energy contribution of phonons, some of these compounds may assume multiple phases as synthesis temperatures are altered, or as ambient temperatures rise or fall.« less

The solubility and activity coefficient of oxygen in salt solutions and brines

NASA Astrophysics Data System (ADS)

Clegg, Simon L.; Brimblecombe, Peter

1990-12-01

Molal oxygen activity coefficients ( γO2) in aqueous salt solutions from 0-100°C have been calculated from O 2 solubility data and established Henry's law constants. Pitzer specific interaction model parameters λO2c, λO2a and ζO2ca have been determined for the following ions: H +, NH +4 Li +, Na +, Rb +, Cs +, Mg 2+, Ca 2+, Ba 2+, Al 3+, OH -, Cl -, Br -, I -, NO -3, SO 2-3, SO 2-4, HCO 3-, CO 32- and PO 3-4. Results confirm that the effect of individual ions on In ( γO2) is additive. Model calculations of γO2 in seawater agree with experimentally derived values at normal salinities to within 0.2% at 298 K and 0.65% at 273 K. Additional data for brines of seawater composition enable the model to be used to represent γO2 empirically to a salinity of 255 S%. The model has thus far only been parameterised from measurements for single salt solutions. Comparisons with experimental data for brines suggest that additional model parameters, obtained from ternary solution data, will be required for accurate representation of γO2 in mixed salt solutions above about 5 mol kg -1 total ion concentration.

Piezo1 forms mechanosensitive ion channels in the human MCF-7 breast cancer cell line

NASA Astrophysics Data System (ADS)

Li, Chouyang; Rezania, Simin; Kammerer, Sarah; Sokolowski, Armin; Devaney, Trevor; Gorischek, Astrid; Jahn, Stephan; Hackl, Hubert; Groschner, Klaus; Windpassinger, Christian; Malle, Ernst; Bauernhofer, Thomas; Schreibmayer, Wolfgang

2015-02-01

Mechanical interaction between cells - specifically distortion of tensional homeostasis-emerged as an important aspect of breast cancer genesis and progression. We investigated the biophysical characteristics of mechanosensitive ion channels (MSCs) in the malignant MCF-7 breast cancer cell line. MSCs turned out to be the most abundant ion channel species and could be activated by negative pressure at the outer side of the cell membrane in a saturable manner. Assessing single channel conductance (GΛ) for different monovalent cations revealed an increase in the succession: Li+ < Na+ < K+ ~Rb+ ~ Cs+. Divalent cations permeated also with the order: Ca2+ < Ba2+. Comparison of biophysical properties enabled us to identify MSCs in MCF-7 as ion channels formed by the Piezo1 protein. Using patch clamp technique no functional MSCs were observed in the benign MCF-10A mammary epithelial cell line. Blocking of MSCs by GsMTx-4 resulted in decreased motility of MCF-7, but not of MCF-10A cells, underscoring a possible role of Piezo1 in invasion and metastatic propagation. The role of Piezo1 in biology and progression of breast cancer is further substantiated by markedly reduced overall survival in patients with increased Piezo1 mRNA levels in the primary tumor.

Ab initio study of the neutral and anionic alkali and alkaline earth hydroxides: Electronic structure and prospects for sympathetic cooling of OH−

PubMed Central

2017-01-01

We have performed a systematic ab initio study on alkali and alkaline earth hydroxide neutral (MOH) and anionic (MOH−) species where M = Li, Na, K, Rb, Cs or Be, Mg, Ca, Sr, Ba. The CCSD(T) method with extended basis sets and Dirac-Fock relativistic effective core potentials for the heavier atoms has been used to study their equilibrium geometries, interaction energies, electron affinities, electric dipole moment, and potential energy surfaces. All neutral and anionic species exhibit a linear shape with the exception of BeOH, BeOH−, and MgOH−, for which the equilibrium structure is found to be bent. Our analysis shows that the alkaline earth hydroxide anions are valence-bound whereas the alkali hydroxide anions are dipole bound. In the context of sympathetic cooling of OH− by collision with ultracold alkali and alkaline earth atoms, we investigate the 2D MOH− potential energy surfaces and the associative detachment reaction M + OH→− MOH + e−, which is the only energetically allowed reactive channel in the cold regime. We discuss the implication for the sympathetic cooling of OH− and conclude that Li and K are the best candidates for an ultracold buffer gas. PMID:28527437

Biomonitoring of 37 trace elements in blood samples from inhabitants of northern Germany by ICP-MS.

PubMed

Heitland, Peter; Köster, Helmut D

2006-01-01

The trace elements Ag, As, Au, B, Ba, Be, Bi, Cd, Ce, Co, Cs, Cu, Ga, Hf, Hg, In, La, Mn, Mo, Ni, Pb, Pd, Rb, Rh, Ru, Sb, Se, Sn, Sr, Te, Th, Tl, U, V, W, Y and Zr were determined in 130 human blood samples from occupationally non-exposed volunteers living in the greater area of Bremen in northern Germany. The blood samples were collected in lithium heparin monovettes developed for trace metal determination and were analysed by inductively coupled plasma mass spectrometry (ICP-MS) with an octopole-based collision/reaction cell. For sample introduction into the ICP, the blood samples were diluted 1/10 (V/V) with a 0.1% Triton-X-100 and 0.5% (V/V) ammonia solution. The method validation of our developed routine method is described for all 37 elements and results about internal and external quality assurance are discussed. Information on exposure conditions of all human subjects were collected by questionnaire-based interviews, including smoking habits, seafood consumption and the type of dental alloys in the teeth. Mean values, geometric mean values, ranges and selected percentiles of all elemental concentrations in human blood are presented, which helps toxicologists and clinical chemists planning research about exposition to metals and health effects caused by exposition to metals.

Transfer parameters for ICRP's Reference Animals and Plants in a terrestrial Mediterranean ecosystem.

PubMed

Guillén, J; Beresford, N A; Baeza, A; Izquierdo, M; Wood, M D; Salas, A; Muñoz-Serrano, A; Corrales-Vázquez, J M; Muñoz-Muñoz, J G

2018-06-01

A system for the radiological protection of the environment (or wildlife) based on Reference Animals and Plants (RAPs) has been suggested by the International Commission on Radiological Protection (ICRP). To assess whole-body activity concentrations for RAPs and the resultant internal dose rates, transfer parameters are required. However, transfer values specifically for the taxonomic families defined for the RAPs are often sparse and furthermore can be extremely site dependent. There is also a considerable geographical bias within available transfer data, with few data for Mediterranean ecosystems. In the present work, stable element concentrations (I, Li, Be, B, Na, Mg, Al, P, S, K. Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Rb, Sr, Mo, Ag, Cd, Cs, Ba, Tl, Pb and U) in terrestrial RAPs, and the corresponding whole-body concentration ratios, CR wo , were determined in two different Mediterranean ecosystems: a Pinewood and a Dehesa (grassland with disperse tree cover). The RAPs considered in the Pinewood ecosystem were Pine Tree and Wild Grass; whereas in the Dehesa ecosystem those considered were Deer, Rat, Earthworm, Bee, Frog, Duck and Wild Grass. The CR wo values estimated from these data are compared to those reported in international compilations and databases. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Neutron activation analysis of some building materials

NASA Astrophysics Data System (ADS)

Salagean, M. N.; Pantelica, A. I.; Georgescu, I. I.; Muntean, M. I.

1999-01-01

Concentrations of As, Au, Ba, Br, Ca, Ce, Co, Cr, Cs, Eu, Fe, Hf, K, La, Lu, Mo, Na, Nd, Rb, Sb, Sc, Sr, Ta, Tb, Th, U. Yb, W and Zn in seven Romanian building materials were determined by the Instrumental Neutron Activation Analysis (INAA) method using the VVR-S Reactor of NIPNE- Bucharest. Raw matarials used in cement obtaining ≈ 75% of limestone and ≈ 25% of clay, cement samples from three different factories, furnace slag, phosphogypsum, and a type of brick have been analyzed. The brick was compacted from furnace slay, fly coal ash, phosphogypsum, lime and cement. The U, Th and K concentrations determined in the brick are in agreement with the natural radioactivity measurements of226Ra,232Th and40K. These specific activities were found about twice and 1.5 higher than the accepted levels in the case of226Ra and232Th, as well as40K, respectively. By consequence, the investigated brick is considered a radioactive waste. The rather high content of Co, Cr, K, Th, and Zh in the brick is especially due to the slag and fly ash, the main componets. The presence of U, Th and K in slag is mainly correlated with the limestone and dolomite as fluxes in matallurgy.

Trace element geochemistry of Archean volcanic rocks

NASA Technical Reports Server (NTRS)

Jahn, B.-M.; Shih, C.-Y.; Murthy, V. R.

1974-01-01

The K, Rb, Sr, Ba and rare-earth-element contents of some Archean volcanic rocks from the Vermilion greenstone belt, northeast Minnesota, were determined by the isotopic dilution method. The characteristics of trace element abundances, supported by the field occurrences and major element chemistry, suggest that these volcanic rocks were formed in an ancient island arc system.

Primary charge separation between P* and B A: Electron-transfer pathways in native and mutant GM203L bacterial reaction centers

NASA Astrophysics Data System (ADS)

Yakovlev, Andrey G.; Jones, Michael R.; Potter, Jane A.; Fyfe, Paul K.; Vasilieva, Lyudmila G.; Shkuropatov, Anatoli Ya.; Shuvalov, Vladimir A.

2005-12-01

Coherent components in the dynamics of decay of stimulated emission from the primary electron donor excited state P*, and of population of the product charge-separated states P+BA- and P+HA-, were studied in GM203L mutant reaction centers (RCs) of Rhodobacter (Rb.) sphaeroides by measuring oscillations in the kinetics of absorbance changes at 940 nm (P* stimulated emission region), 1020 nm ( BA- absorption region) and 760 nm (H A bleaching region). Absorbance changes were induced by excitation of P (870 nm) with 18 fs pulses at 90 K. In the GM203L mutant, replacement of Gly M203 by Leu results in exclusion of the crystallographically defined water molecule (HOH55) located close to the oxygen of the 13 1-keto carbonyl group of B A and to His M202, which provides the axial ligand to the Mg of the P B bacteriochlorophyll. The results of femtosecond measurements were compared with those obtained with Rb. sphaeroides R-26 RCs containing an intact water HOH55. The main consequences of the GM203L mutation were found to be as follows: (i) a low-frequency oscillation at 32 cm -1, which is characteristic of the HOH55-containing RCs, disappears from the kinetics of absorbance changes at 1020 and 760 nm in the mutant RC; (ii) electron transfer from P* to B A in the wild type RC was characterized by two time constants of 1.1 ps (80%) and 4.3 ps (20%), but in the GM203L mutant was characterized by a single time constant of 4.3 ps, demonstrating a slowing of primary charge separation. The previously postulated rotation of water HOH55 with a fundamental frequency of 32 cm -1, triggered by electron transfer from P* to B A, was confirmed by observation of an isotopic shift of the 32 cm -1 oscillation in the kinetics of P+BA- population in deuterated, pheophytin-modified RCs of Rb. sphaeroides R-26, by a factor of 1.6. These data are discussed in terms of the influence of water HOH55 on the energetics of the P∗→P+BA- reaction, and protein dynamic events that occur on the time scale of this reaction.

Electrochemistry of Europium(III) Chloride in 3 LiCl – NaCl, 3 LiCl – 2 KCl, LiCl – RbCl, and 3 LiCl – 2 CsCl Eutectics at Various Temperatures

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

Schroll, Cynthia A.; Chatterjee, Sayandev; Levitskaia, Tatiana G.

Here we report the effect of changing the eutectic melt composition on the electrochemical properties of europium(III) chloride under pyroprocessing conditions. The number of electrons transferred, redox potentials and diffusion coefficients were determined using various electrochemical and spectroelectrochemical techniques in four different eutectic mixtures (3 LiCl - NaCl, 3 LiCl - 2 KCl, 3 LiCl - RbCl, and 3 LiCl - 2 CsCl) while varying the temperature of the melt. It was determined that Eu3+ undergoes a one electron reduction to Eu2+ in each melt at all temperatures evaluated. Within all the melts a positive shift in the redox potentialmore » as well as an increase in the diffusion coefficient for Eu3+ was observed as the temperature increased. Also observed was a positive shift in the redox potential and increase in the diffusion coefficient for Eu3+ as the weighted average of the cationic radii for the melt decreased.« less

Superconducting critical fields of alkali and alkaline-earth intercalates of MoS2

NASA Technical Reports Server (NTRS)

Woollam, J. A.; Somoano, R. B.

1976-01-01

Results are reported for measurements of the critical-field anisotropy and temperature dependence of group-VIB semiconductor MoS2 intercalated with the alkali and alkaline-earth metals Na, K, Rb, Cs, and Sr. The temperature dependences are compared with present theories on the relation between critical field and transition temperature in the clean and dirty limits over the reduced-temperature range from 1 to 0.1. The critical-field anisotropy data are compared with predictions based on coupled-layers and thin-film ('independent-layers') models. It is found that the critical-field boundaries are steep in all cases, that the fields are greater than theoretical predictions at low temperatures, and that an unusual positive curvature in the temperature dependence appears which may be related to the high anisotropy of the layer structure. The results show that materials with the largest ionic intercalate atom diameters and hexagonal structures (K, Rb, and Cs compounds) have the highest critical temperatures, critical fields, and critical-boundary slopes; the critical fields of these materials are observed to exceed the paramagnetic limiting fields.

Spectroscopic study of carbaryl sorption on smectite from aqueous suspension.

PubMed

de Oliveira, Maurilio Fernandes; Johnston, Cliff T; Premachandra, G S; Teppen, Brian J; Li, Hui; Laird, David A; Zhu, Dongqiang; Boyd, Stephen A

2005-12-01

Sorption of carbaryl (1-naphthyl-N-methyl-carbamate) from aqueous suspension to smectite was studied using Fourier transform infrared (FTIR), high-performance liquid chromatography (HPLC) (for batch sorption), and quantum chemical methods. The amount of carbaryl sorbed was strongly dependent on the surface-charge density of the smectite with more sorption occurring on the two "low" surface-charge density smectites (SHCa-1 and SWy-2) compared to that of the high surface-charge SAz-1 smectite. In addition, the amount of carbaryl sorbed was strongly dependent on the nature of the exchangeable cation and followed the order of Ba approximately Cs approximately Ca > Mg approximately K > Na approximately Li for SWy-2. A similartrend was found for hectorite (SHCa-1) of Cs > Ba > Ca > K approximately Mg > Na approximately Li. Using the shift of the carbonyl stretching band as an indicator of the strength of interaction between carbaryl and the exchangeable cation, the observed order was Mg > Ca > Ba approximately K > Na > Cs. The position of the carbonyl stretching band shifted to lower wavenumbers with increasing ionic potential of the exchangeable cation. Density functional theory predicted a cation-induced lengthening of the C=O bond, resulting from the carbonyl group interacting directly with the exchangeable cation in support of the spectroscopic observations. Further evidence was provided by a concomitant shift in the opposite direction by several vibrational bands in the 1355-1375 cm(-1) region assigned to stretching bands of the carbamate N-Ccarbonyl and Oether-Ccarbonyl bonds. These data indicate that carbaryl sorption is due, in part, to site-specific interactions between the carbamate functional group and exchangeable cations, as evidenced by the FTIR data. However, these data suggest that hydrophobic interactions also contribute to the overall amount of carbaryl sorbed. For example, the FTIR data indicated thatthe weakest interaction occurred when Cs+ was the exchangeable cation. In contrast, the highest amount of carbaryl sorption was observed on Cs-exchanged smectite. Of all the cations studied, Cs has the lowest enthalpy of hydration. It is suggested that this low hydration energy provides the carbaryl with greater access to the hydrophobic regions of the siloxane surface.

Petrogenesis of Western Cascades Silicic Volcanics Near Sweet Home, Oregon

NASA Astrophysics Data System (ADS)

Cook, G. W.; White, C. M.

2002-12-01

Silicic lavas in the Menagerie Wilderness east of Sweet Home, Oregon are Oligocene to Miocene in age and range in composition from dacite (low K) to trachydacite (high K) and rhyolite (medium K). Three distinct silicic centers have been distinguished through a combination of field observation, chemistry and petrography. Phenocryst assemblages in rocks of the centers are plagioclase-hornblende-magnetite (Rooster Rock rhyolite), plagioclase-quartz-magnetite (Soda Fork rhyolite) and quartz-plagioclase-biotite-hornblende-magnetite (Moose Mt. rhyolite). The silicic volcanics in the study area are similar in terms of mineral content and overall chemical composition. Despite this, chemical evidence suggests that the three centers are petrologically unrelated. REE variations and least squares modeling of major element compositions are consistent with fractionation of plagioclase and hornblende. The rhyolites have moderate Eu anomalies and have flat MREE and HREE signatures. Least squares models and bivariate plots of major and trace elements also suggest fractionation of the aforementioned phases for both the andesite to dacite, and dacite to rhyolite steps. Comparisons with similar silicic centers show the Menagerie rocks share affinities with High Cascades rocks thought to have been derived through fractional crystallization (Crater Lake and South Sister). Plots of ratios of incompatible trace elements were utilized to determine if assimilation played some role alongside fractional crystallization in differentiation. Plots of Ba/La vs. Ba, Rb/Zr vs. Rb and Rb/Th vs. Rb show systematic positive increases in the ratios between a plausible parent magma (icelandite) and the rhyolites. These increases are not easily explained by fractional crystallization but can be modeled by assimilation of silicic crust. Overall, it seems likely that the three centers evolved independently through similar petrogenetic processes from an andesitic parent. The most plausible petrogenetic scenario involves some combination of fractional crystallization and assimilation of partial melts of silicic crust.

Sorption--desorption studies on granite. I. Initial studies of strontium, technetium, cesium, barium, cerium, europium, uranium, plutonium, and americium

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

Erdal, B.R.; Aguilar, R.D.; Bayhurst, B.P.

Distribution ratios were determined for sorption--desorption of radioactive tracers between the Climax Stock granite (quartz monzonite porphyry) obtained at Nevada Test Site and a water prepared to be resonably representative of the natural composition of water in equilibrium with the Climax Stock granite. The measurements were performed at 22 and 70{sup 0}C under atmospheric oxygen conditions. Elements given in order of increasing distribution coefficient at ambient temperature are: U(VI), Sr, Tc(VII), Ba, Ce(III), Cs, Eu(III), Pu, and Am. At 70{sup 0}C the order is: Tc(VII), Sr, Ce(III), Eu(III), Ba, Cs, Pu, and Am. The effects of surface area and mineralogymore » on sorption were also investigated.« less

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

Roederer, Ian U., E-mail: iur@umich.edu

The heaviest metals found in stars in most ultra-faint dwarf (UFD) galaxies in the Milky Way halo are generally underabundant by an order of magnitude or more when compared with stars in the halo field. Among the heavy elements produced by n -capture reactions, only Sr and Ba can be detected in red giant stars in most UFD galaxies. This limited chemical information is unable to identify the nucleosynthesis process(es) responsible for producing the heavy elements in UFD galaxies. Similar [Sr/Ba] and [Ba/Fe] ratios are found in three bright halo field stars, BD−18°5550, CS 22185–007, and CS 22891–200. Previous studiesmore » of high-quality spectra of these stars report detections of additional n -capture elements, including Eu. The [Eu/Ba] ratios in these stars span +0.41 to +0.86. These ratios and others among elements in the rare Earth domain indicate an r -process origin. These stars have some of the lowest levels of r -process enhancement known, with [Eu/H] spanning −3.95 to −3.32, and they may be considered nearby proxies for faint stars in UFD galaxies. Direct confirmation, however, must await future observations of additional heavy elements in stars in the UFD galaxies themselves.« less

High-pressure electrical resistivity studies for Ba1-xCsxFe2Se3

NASA Astrophysics Data System (ADS)

Kawashima, C.; Soeda, H.; Takahashi, H.; Hawai, T.; Nambu, Y.; Sato, T. J.; Hirata, Y.; Ohgushi, K.

2017-10-01

High-pressure electrical resistance measurements were performed for iron-based ladder material Ba1-xCsxFe2Se3 (x = 0.25 and 0.65) using a diamond anvil cell (DAC). Recent high-pressure study revealed that iron-based ladder material BaFe2S3 exhibits an insulator-metal transition and superconductivity, and this discovery would provide important insight for understanding the mechanism of iron-based superconductors. Therefore, it is intriguing to investigate the high-pressure properties for the iron-based ladder material Ba1-xCsxFe2Se3 system. The parent compounds BaFe2Se3 and CsFe2Se3 show insulating and magnetic ordering features. For Ba1-xCsxFe2Se3 system, no magnetic ordering is observed for x = 0.25 and minimum charge gap was estimated for x = 0.65. The insulator-metal transitions are observed in both materials.

High-pressure electrical resistivity studies for Ba1-xCsxFe2Se3

NASA Astrophysics Data System (ADS)

Kawashima, C.; Soeda, H.; Takahashi, H.; Hawai, T.; Nambu, Y.; Sato, T. J.; Hirata, Y.; Ohgushi, K.

2017-10-01

High-pressure electrical resistance measurements were performed for iron-based ladder material Ba1-xCsxFe2Se3 (x = 0.25 and 0.65) using a diamond anvil cell (DAC). Recent high-pressure study revealed that iron-based ladder material BaFe2S3 exhibits an insulator- metal transition and superconductivity, and this discovery would provide important insight for understanding the mechanism of iron-based superconductors. Therefore, it is intriguing to investigate the high-pressure properties for the iron-based ladder material Ba1-xCsxFe2Se3 system. The parent compounds BaFe2Se3 and CsFe2Se3 show insulating and magnetic ordering features. For Ba1-xCsxFe2Se3 system, no magnetic ordering is observed for x = 0.25 and minimum charge gap was estimated for x = 0.65. The insulator-metal transitions are observed in both materials.

Copolymer Networks From Oligo(ε-caprolactone) and n-Butyl Acrylate Enable a Reversible Bidirectional Shape-Memory Effect at Human Body Temperature.

PubMed

Saatchi, Mersa; Behl, Marc; Nöchel, Ulrich; Lendlein, Andreas

2015-05-01

Exploiting the tremendous potential of the recently discovered reversible bidirectional shape-memory effect (rbSME) for biomedical applications requires switching temperatures in the physiological range. The recent strategy is based on the reduction of the melting temperature range (ΔT m ) of the actuating oligo(ε-caprolactone) (OCL) domains in copolymer networks from OCL and n-butyl acrylate (BA), where the reversible effect can be adjusted to the human body temperature. In addition, it is investigated whether an rbSME in the temperature range close or even above Tm,offset (end of the melting transition) can be obtained. Two series of networks having mixtures of OCLs reveal broad ΔTm s from 2 °C to 50 °C and from -10 °C to 37 °C, respectively. In cyclic, thermomechanical experiments the rbSME can be tailored to display pronounced actuation in a temperature interval between 20 °C and 37 °C. In this way, the application spectrum of the rbSME can be extended to biomedical applications. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

All-Solid-State Mechanochemical Synthesis and Post-Synthetic Transformation of Inorganic Perovskite-type Halides.

PubMed

Pal, Provas; Saha, Sujoy; Banik, Ananya; Sarkar, Arka; Biswas, Kanishka

2018-02-06

All-inorganic and hybrid perovskite type halides are generally synthesized by solution-based methods, with the help of long chain organic capping ligands, complex organometallic precursors, and high boiling organic solvents. Herein, a room temperature, solvent-free, general, and scalable all-solid-state mechanochemical synthesis is demonstrated for different inorganic perovskite type halides, with versatile structural connectivity in three (3D), two (2D), and zero (0D) dimensions. 3D CsPbBr 3 , 2D CsPb 2 Br 5 , 0D Cs 4 PbBr 6 , 3D CsPbCl 3 , 2D CsPb 2 Cl 5 , 0D Cs 4 PbCl 6 , 3D CsPbI 3 , and 3D RbPbI 3 have all been synthesized by this method. The all-solid-state synthesis is materialized through an inorganic retrosynthetic approach, which directs the decision on the solid-state precursors (e.g., CsX and PbX 2 (X=Cl/Br/I) with desired stoichiometric ratios. Moreover, post-synthetic structural transformations from 3D to 2D and 0D perovskite halides were performed by the same mechanochemical synthetic approach at room temperature. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Elemental marking of arthropod pests in agricultural systems: single and multigenerational marking

Treesearch

Jane Leslie Hayes

1991-01-01

Use of elemental markers to study movement of arthropod pests of field crops is reviewed. Trace elements, rubidium (Rb) and cesium (Cs), have provided a nondisruptive method of marking natural adult populations via developmental stage consumption of treated host plants. Multigenerational marking occurs with the transfer of elemental markers from marked adults to...

An exploratory study of recycled sputtering and CsF2- current enhancement for AMS

NASA Astrophysics Data System (ADS)

Zhao, X.-L.; Charles, C. R. J.; Cornett, R. J.; Kieser, W. E.; MacDonald, C.; Kazi, Z.; St-Jean, N.

2016-01-01

The analysis of 135Cs/Cs ratios at levels below 10-12 by accelerator mass spectrometry (AMS) would preferably use commonly available negative ion injection systems. The sputter ion sources in these injectors should ideally produce currents of Cs- or Cs-containing molecular anions approaching μA levels from targets containing mg quantities of Cs. However, since Cs is the most electro-positive stable element in nature with a low electron affinity, the generation of large negative atomic, or molecular beams containing Cs, has been very challenging. In addition, the reduction of the interferences from the 135Ba isobar and the primary 133Cs+ beam used for sputtering are also necessary. The measurement of a wide range of the isotope ratios also requires the ion source memory of previous samples be minimized. This paper describes some progresses towards a potential solution of all these problems by recycled sputtering using fluorinating targets of PbF2 with mg CsF mixed in. The problems encountered indicate that considerable further studies and some redesign of the present ion sources will be desirable.

Identification of goat milk powder by manufacturer using multiple chemical parameters.

PubMed

McLeod, Rebecca J; Prosser, Colin G; Wakefield, Joshua W

2016-02-01

Concentrations of multiple elements and ratios of stable isotopes of carbon and nitrogen were measured and combined to create a chemical fingerprint of production batches of goat whole milk powder (WMP) produced by different manufacturers. Our objectives were to determine whether or not differences exist in the chemical fingerprint among samples of goat WMP produced at different sites, and assess temporal changes in the chemical fingerprint in product manufactured at one site. In total, 58 samples of goat WMP were analyzed by inductively coupled plasma-mass spectrometry as well as isotope ratio mass spectrometry and a suite of 13 elements (Li, Na, Mg, K, Ca, Mn, Cu, Zn, Rb, Sr, Mo, Cs, and Ba), δ(13)C, and δ(15)N selected to create the chemical fingerprint. Differences in the chemical fingerprint of samples between sites and over time were assessed using principal components analysis and canonical analysis of principal coordinates. Differences in the chemical fingerprints of samples between production sites provided a classification success rate (leave-one-out classification) of 98.1%, providing a basis for using the approach to test the authenticity of product manufactured at a site. Within one site, the chemical fingerprint of samples produced at the beginning of the production season differed from those produced in the middle and late season, driven predominantly by lower concentrations of Na, Mg, K, Mn, and Rb, and higher concentrations of Ba and Cu. This observed temporal variability highlights the importance of obtaining samples from throughout the season to ensure a representative chemical fingerprint is obtained for goat WMP from a single manufacturing site. The reconstitution and spray drying of samples from one manufacturer by the other manufacturer enabled the relative influence of the manufacturing process on the chemical fingerprint to be examined. It was found that such reprocessing altered the chemical fingerprint, although the degree of alteration varied among samples and individual elements. The findings of this study support the use of trace elements and stable isotope ratios to test the authenticity of goat WMP, which can likely be applied to other dairy goat products. This approach could be used test to the factory of origin (and potentially batch of origin) of products in the supply chain, thus providing the ability to audit the supply chain and monitor for fraudulent activity. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Selectivity of bis(calix[4]diquinone) ionophores towards metal ions in solvent dimethylsulfoxide: a molecular mechanics and molecular dynamics study.

PubMed

Felix, Vitor; Drew, Michael G B; Webber, Philip R A; Beer, Paul D

2006-01-28

Molecular modelling studies have been carried out on two bis(calix[4]diquinone) ionophores, each created from two (calix[4]diquinone)arenes bridged at their bottom rims via alkyl chains (CH(2))(n), 1: n = 3, 2; n = 4, in order to understand the reported selectivity of these ligands towards different sized metal ions such as Na(+), K(+), Rb(+), and Cs(+) in dmso solution. Conformational analyses have been carried out which show that in the lowest energy conformations of the two macrocycles, the individual calix[4]diquinones exhibit a combination of partial cone, 1,3-alternate and cone conformations. The interactions of these alkali metals with the macrocycles have been studied in the gas phase and in a periodic box of solvent dmso by molecular mechanics and molecular dynamics calculations. Molecular mechanics calculations have been carried out on the mode of entry of the ions into the macrocycles and suggest that this is likely to occur from the side of the central cavity, rather than through the main axis of the calix[4]diquinones. There are energy barriers of ca. 19 kcal mol(-1) for this entry path in the gas phase, but in solution no energy barrier is found. Molecular dynamics simulations show that in both 1 and 2, though particularly in the latter macrocycle, one or two solvent molecules are bonded to the metal throughout the course of the simulation, often to the exclusion of one or more of the ether oxygen atoms. By contrast the carbonyl oxygen atoms remain bonded to the metal atoms throughout with bond lengths that remain significantly less than those to the ether oxygen atoms. Free energy perturbation studies have been carried out in dmso and indicate that for 1, the selectivity follows the order Rb(+) approximately K(+) > Cs(+) > Na(+), which is partially in agreement with the experimental results. The energy differences are small and indeed the ratio between stability constants found for Cs(+) and K(+) complexes is only 0.60, showing that has only a slight preference for K(+). For the larger receptor , which is better suited to metal complexation, the binding affinity follows the pattern Cs(+) > Rb(+) > K(+) > Na(+), with energy differences of 5.75, 2.61, 2.78 kcal mol(-1) which is perfectly consistent with experimental results.

Volatilization, transport and sublimation of metallic and non-metallic elements in high temperature gases at Merapi Volcano, Indonesia

USGS Publications Warehouse

Symonds, R.B.; Rose, William I.; Reed, M.H.; Lichte, F.E.; Finnegan, David L.

1987-01-01

Condensates, silica tube sublimates and incrustations were sampled from 500-800??C fumaroles and lava samples were collected at Merapi Volcano, Indonesia in Jan.-Feb., 1984. With respect to the magma, Merapi gases are enriched by factors greater than 105 in Se, Re, Bi and Cd; 104-105 in Au, Br, In, Pb and W; 103-104 in Mo, Cl, Cs, S, Sn and Ag; 102-103 in As, Zn, F and Rb; and 1-102 in Cu, K, Na, Sb, Ni, Ga, V, Fe, Mn and Li. The fumaroles are transporting more than 106 grams/day ( g d) of S, Cl and F; 104-106 g/d of Al, Br, Zn, Fe, K and Mg; 103-104 g d of Pb, As, Mo, Mn, V, W and Sr; and less than 103 g d of Ni, Cu, Cr, Ga, Sb, Bi, Cd, Li, Co and U. With decreasing temperature (800-500??C) there were five sublimate zones found in silica tubes: 1) cristobalite and magnetite (first deposition of Si, Fe and Al); 2) K-Ca sulfate, acmite, halite, sylvite and pyrite (maximum deposition of Cl, Na, K, Si, S, Fe, Mo, Br, Al, Rb, Cs, Mn, W, P, Ca, Re, Ag, Au and Co); 3) aphthitalite (K-Na sulfate), sphalerite, galena and Cs-K. sulfate (maximum deposition of Zn, Bi, Cd, Se and In; higher deposition of Pb and Sn); 4) Pb-K chloride and Na-K-Fe sulfate (maximum deposition of Pb, Sn and Cu); and 5) Zn, Cu and K-Pb sulfates (maximum deposition of Pb, Sn, Ti, As and Sb). The incrustations surrounding the fumaroles are also chemically zoned. Bi, Cd, Pb, W, Mo, Zn, Cu, K, Na, V, Fe and Mn are concentrated most in or very close to the vent as expected with cooling, atmospheric contamination and dispersion. The highly volatile elements Br, Cl, As and Sb are transported primarily away from high temperature vents. Ba, Si, P, Al, Ca and Cr are derived from wall rock reactions. Incomplete degassing of shallow magma at 915??C is the origin of most of the elements in the Merapi volcanic gas, although it is partly contaminated by particles or wall rock reactions. The metals are transported predominantly as chloride species. As the gas cools in the fumarolic environment, it becomes saturated with sublimate phases that fractionate from the gas in the order of their equilibrium saturation temperatures. Devolatilization of a cooling batholith could transport enough acids and metals to a hydrothermal system to play a significant role in forming an ore deposit. However, sublimation from a high temperature, high velocity carrier gas is not efficient enough to form a large ore deposit. Re, Se, Cd and Bi could be used as supporting evidence for magmatic fluid transport in an ore deposit. ?? 1987.

Assessment of trace metal levels in size-resolved particulate matter in the area of Leipzig

NASA Astrophysics Data System (ADS)

Fomba, Khanneh Wadinga; van Pinxteren, Dominik; Müller, Konrad; Spindler, Gerald; Herrmann, Hartmut

2018-03-01

Size-resolved trace metal concentrations at four sites in Leipzig (Germany) and its surrounding were assessed between the winter of 2013 and the summer of 2015. The measurements were performed in parallel at; traffic dominated (Leipzig - Mitte, LMI), traffic and residential dominated (Eisenbahnstrasse, EIB), urban background (TROPOS, TRO) and regional background (Melpitz, MEL) sites. In total, 19 trace metals, i.e. K, Ca, Ti, Mn, Fe, Cu, Zn, As, Se, Ba, V, Pb, Ni, Cr, Sr, Sn, Sb, Co and Rb were analysed using total reflection x-ray fluorescence (TXRF). The major metals were Fe, K and Ca with concentrations ranging between; 31-440 ng/m3, 42-153 ng/m3 and 24-322 ng/m3, respectively, while the trace metals with the lowest concentrations were Co, Rb and Se with concentrations of; < 0.3 ng/m3, <0.5 ng/m3 and 0.5-0.7 ng/m3, respectively. PM10 trace metal concentrations during easterly air mass inflow especially at the background sites were in average 70% higher in the winter and 30% higher in the summer in comparison to westerly air mass inflow. Traffic at LMI contributed to about 75% of Cr, Ba, Cu, Sb, Sn, Ca, Co, Mn, Fe and Ti concentrations while regional activities contributed to more than 70% of K, Rb, Pb, Se, As and V concentrations. Traffic dominated trace metals were often observed in the coarse mode while the regional background dominated trace metals were often observed in the fine mode. Trace metal sources were related to crustal matter and road dust re-suspension for metals such as Ca, Fe, Co, Sr, and Ti, brake and tire wear (Cu, Sb, Ba, Fe, Zn, Pb), biomass burning (K, Rb), oil and coal combustion (V, Zn, As, Pb). Crustal matter contributed 5-12% in winter and 8-19% in summer of the PM10 mass. Using Cu and Zn as markers for brake and tire wear, respectively, the estimated brake and tire wear contributions to the PM10 mass were 0.1-0.8% and 1.7-2.9%, respectively. The higher contributions were observed at the traffic sites while the lower contributions were observed at the regional background site. In total, non-exhaust emissions could account for about 10-22% of the PM10 mass in the summer and about 7-15% of the PM10 mass in the winter.

Atomic Clocks and Variations of the FIne Structure Constant

NASA Technical Reports Server (NTRS)

Prestage, John D.; Tjoelker, Robert L.; Maleki, Lute

1995-01-01

We describe a new test for possible variations of the fine structure constant alpha by comparisons of rates between clocks based on hyperfine transitions in alkali atoms with different atomic number Z. H-maser, Cs, and Hg(+) clocks have a different dependence on alpha via relativistic contributions of order (Z-alpha)(sup 2). Recent H-maser vs Hg(+) clock comparison data improve laboratory limits on a time variation by 100-fold to give dot-alpha less than or equal to 3.7 x 10(exp -14)/yr. Future laser cooled clocks (Be(+), Rb, Cs, Hg(+), etc.), when compared, will yield the most sensitive of all tests for dot-alpha/alpha.

Alkali metal and ammonium fluoro(trifluoroacetato)metallates M'[ M''3(μ3-F)(CF3COO)6(CF3COOH)3], where M' = Li, Na, K, NH4, Rb, or Cs and M'' = Ni or Co. Synthesis and crystal structures

NASA Astrophysics Data System (ADS)

Tereshchenko, D. S.; Morozov, I. V.; Boltalin, A. I.; Karpova, E. V.; Glazunova, T. Yu.; Troyanov, S. I.

2013-01-01

A series of fluoro(trifluoroacetato)metallates were synthesized by crystallization from solutions in trifluoroacetic acid containing nickel(II) or cobalt(II) nitrate hydrates and alkali metal or ammonium fluorides: Li[Ni3(μ3-F)(CF3COO)6(CF3COOH)3](CF3COOH)3 ( I), M'[Ni3(μ3-F)(CF3COO)6(CF3COOH)3] ( M' = Na ( II), NH4 ( IV), Rb ( V), and Cs ( VI)), NH4[Co3(μ3-F) (CF3COO)6(CF3COOH)3] ( III), and Cs[Ni3(μ3-F)(CF3COO)6(CF3COOH)3](CF3COOH)0.5 ( VII). The crystal structures of these compounds were determined by single-crystal X-ray diffraction. All structures contain triangular trinuclear complex anions [ M 3″(μ3-F)(CF3COO)6(CF3COOH)3]- ( M″ = Ni, Co) structurally similar to trinuclear 3d metal oxo carboxylate complexes. The three-coordinated F atom is located at the center of the triangle formed by Ni(II) or Co(II) atoms. The metal atoms are linked in pairs by six bridging trifluoroacetate groups located above and below the plane of the [ M″3 F] triangle. The oxygen atoms of the axial CF3COOH molecules complete the coordination environment of M″ atoms to an octahedron.

An accurate potential model for the a3Σu+ state of the alkali dimers Na2, K2, Rb2, and Cs2

NASA Astrophysics Data System (ADS)

Lau, Jascha A.; Toennies, J. Peter; Tang, K. T.

2016-11-01

A modified semi-empirical Tang-Toennies potential model is used to describe the a3Σu+ potentials of the alkali dimers. These potentials are currently of interest in connection with the laser manipulation of the ultracold alkali gases. The fully analytical model is based on three experimental parameters, the well depth De, well location Re, and the harmonic vibrational frequency ωe of which the latter is only slightly optimized within the range of the literature values. Comparison with the latest spectroscopic data shows good agreement for Na2, K2, Rb2, and Cs2, comparable to that found with published potential models with up to 55 parameters. The differences between the reduced potential of Li2 and the conformal reduced potentials of the heavier dimers are analyzed together with why the model describes Li2 less accurately. The new model potential provides a test of the principle of corresponding states and an excellent first order approximation for further optimization to improve the fits to the spectroscopic data and describe the scattering lengths and Feshbach resonances at ultra-low temperatures.

Superconductivity in the 2-Dimensional Homologous Series AMm Bi3 Q5+m (m=1, 2) (A=Rb, Cs; M=Pb, Sn; Q=Se, Te).

PubMed

Malliakas, Christos D; Chung, Duck Young; Claus, Helmut; Kanatzidis, Mercouri G

2018-05-17

Superconductivity in the two-dimensional AM m Bi 3 Q 5+m family of semimetals is reported. The AMBi 3 Te 6 (m=1) and AM 2 Bi 3 Te 7 (m=2) members of the homologous series with A=Rb, Cs and M=Pb, Sn undergo a bulk superconducting transition ranging from 2.7 to 1.4 K depending on the composition. The estimated superconducting volume fraction is about 90 %. Superconducting phase diagrams as a function of chemical pressure are constructed for the solid solution products of each member of the homologous series, AMBi 3-x Sb x Te 6-y Se y and AM 2 Bi 3-x Sb x Te 7-y Se y (0≤x≤3 or 0≤y≤2). The structural flexibility of the ternary AM m M' 3 Te 5+m semiconducting homology to form isostructural analogues with a variety of metals, M=Pb, Sn; M'=Bi, Sb, gives access to a large number of electronic configurations and superconductivity due to chemical pressure effects. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Gamma ray induced decomposition of double nitrates of lanthanum and cerium with some mono and bivalent cations in solid state

NASA Astrophysics Data System (ADS)

Kulkarni, S. P.; Garg, A. N.

Gamma ray induced decomposition of two series of double nitrates; 2M INO 3⋯Ln(NO 3) 3⋯ x H 2O (where MI = NH+4, Na+, K+, Rb+, Cs+; LnIII = La3+, Ce3+ and x = 2 or 4) and 3M II(NO 3) 2·2Ln III(NO 3) 3⋯24H 2O (where MII = Mg2+, Co2+, Zn2+; LnIII = La3+, Ce3+) has been studied in solid state over a wide absorbed dose range at room temperature. G(NO -2) values have been found to depend on the absorbed dose and the nature of cation in both the series of double salts. Radiation sensitivity of lanthanum double nitrates with monovalent cations at an absorbed dose of 158 kGy follows the order NH +4 < Rb + ≅ Cs + < Na + < K + and those of cerium NH +4 < Rb +

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

Tumurugoti, P.; Clark, B.M.; Edwards, D.J.

Hollandite-rich multiphase waste form compositions processed by melt-solidification and spark plasma sintering (SPS) were characterized, compared, and validated for nuclear waste incorporation. Phase identification by x-ray diffraction (XRD) and electron back-scattered diffraction (EBSD) confirmed hollandite as the major phase present in these samples along with perovskite, pyrochlore and zirconolite. Distribution of selected elements observed by wavelength dispersive spectroscopy (WDS) maps indicated that Cs formed a secondary phase during SPS processing, which was considered undesirable. On the other hand, Cs partitioned into the hollandite phase in melt-processed samples. Further analysis of hollandite structure in melt-processed composition by selected area electron diffractionmore » (SAED) revealed ordered arrangement of tunnel ions (Ba/Cs) and vacancies, suggesting efficient Cs incorporation into the lattice.« less

Trace element transport in western Siberian rivers across a permafrost gradient

NASA Astrophysics Data System (ADS)

Pokrovsky, Oleg S.; Manasypov, Rinat M.; Loiko, Sergey V.; Krickov, Ivan A.; Kopysov, Sergey G.; Kolesnichenko, Larisa G.; Vorobyev, Sergey N.; Kirpotin, Sergey N.

2016-03-01

Towards a better understanding of trace element (TE) transport in permafrost-affected Earth surface environments, we sampled ˜ 60 large and small rivers (< 100 to ≤ 150 000 km2 watershed area) of the Western Siberian Lowland (WSL) during spring flood and summer and winter baseflow across a 1500 km latitudinal gradient covering continuous, discontinuous, sporadic and permafrost-free zones. Analysis of ˜ 40 major and TEs in the dissolved (< 0.45 µm) fraction allowed establishing main environmental factors controlling the transport of metals and TEs in rivers of this environmentally important region. No statistically significant effect of the basin size on most TE concentrations was evidenced. Two groups of elements were distinguished: (1) elements that show the same trend throughout the year and (2) elements that show seasonal differences. The first group included elements decreasing northward during all seasons (Sr, Mo, U, As, Sb) marking the underground water influence of river feeding. The elements of the second group exhibited variable behavior in the course of the year. A northward increase during spring period was mostly pronounced for Fe, Al, Co, Zn and Ba and may stem from a combination of enhanced leaching from the topsoil and vegetation and bottom waters of the lakes (spring overturn). A springtime northward decrease was observed for Ni, Cu, Zr and Rb. The increase in element concentration northward was observed for Ti, Ga, Zr and Th only in winter, whereas Fe, Al, rare earth elements (REEs), Pb, Zr, and Hf increased northward in both spring and winter, which could be linked to leaching from peat and transport in the form of Fe-rich colloids. A southward increase in summer was strongly visible for Fe, Ni, Ba, Rb and V, probably due to peat/moss release (Ni, Ba, Rb) or groundwater feeding (Fe, V). Finally, B, Li, Cr, V, Mn, Zn, Cd, and Cs did not show any distinct trend from S to N. The order of landscape component impact on TE concentration in rivers was lakes > bogs > forest. The lakes decreased export of Mn and Co in summer and Ni, Cu, and Rb in spring, presumably due to biotic processes. The lakes enriched the rivers in insoluble lithogenic elements in summer and winter, likely due to TE mobilization from unfrozen mineral sediments. The rank of environmental factors on TE concentration in western Siberian rivers was latitude (three permafrost zones) > season > watershed size. The effect of the latitude was minimal in spring for most TEs but highly visible for Sr, Mo, Sb and U. The main factors controlling the shift of river feeding from surface and subsurface flow to deep underground flow in the permafrost-bearing zone were the depth of the active (unfrozen) seasonal layer and its position in organic or mineral horizons of the soil profile. In the permafrost-free zone, the relative role of carbonate mineral-bearing base rock feeding versus bog water feeding determined the pattern of TE concentration and fluxes in rivers of various sizes as a function of season. Comparison of obtained TE fluxes in WSL rivers with those of other subarctic rivers demonstrated reasonable agreement for most TEs; the lithology of base rocks was the major factor controlling the magnitude of TE fluxes. Climate change in western Siberia and permafrost boundary migration will essentially affect the elements controlled by underground water feeding (DIC, alkaline earth elements (Ca, Sr), oxyanions (Mo, Sb, As) and U). The thickening of the active layer may increase the export of trivalent and tetravalent hydrolysates in the form of organo-ferric colloids. Plant litter-originated divalent metals present as organic complexes may be retained via adsorption on mineral horizon. However, due to various counterbalanced processes controlling element source and sinks in plant-peat-mineral soil-river systems, the overall impact of the permafrost thaw on TE export from the land to the ocean may be smaller than that foreseen with merely active layer thickening and permafrost boundary shift.

Development of High Efficiency Four-Terminal Perovskite-Silicon Tandems

NASA Astrophysics Data System (ADS)

Duong, The Duc

This thesis is concerned with the development of high efficiency four-terminal perovskite-silicon tandem solar cells with the potential to reduce the cost of solar energy. The work focuses on perovskite top cells and can be divided into three main parts: developing low parasitic absorption and efficient semi-transparent perovskite cells, doping perovskite materials with rubidium, and optimizing perovskite material's bandgap with quadruple-cation and mixed-halide. A further section investigates the light stability of optimized bandgap perovskite cells. In a four-terminal mechanically stacked tandem, the perovskite top cell requires two transparent contacts at both the front and rear sides. Through detailed optical and electrical power loss analysis of the tandem efficiency due to non-ideal properties of the two transparent contacts, optimal contact parameters in term of sheet resistance and transparency are identified. Indium doped tin oxide by sputtering is used for both two transparent contacts and their deposition parameters are optimized separately. The semi-transparent perovskite cell using MAPbI3 has an efficiency of more than 12% with less than 12% parasitic absorption and up to 80% transparency in the long wavelength region. Using a textured foil as anti-reflection coating, an outstanding average transparency of 84% in the long wavelength is obtained. The low parasitic absorption allows an opaque version of the semi-transparent perovskite cell to operate efficiently in a filterless spectrum splitting perovskite-silicon tandem configuration. To further enhance the performance of perovskite cells, it is essential to improve the quality of perovskite films. This can be achieved with mixed-perovskite FAPbI3/MAPbBr3. However, mixed-perovskite films normally contain small a small amount of a non-perovskite phase, which is detrimental for the cell performance. Rb-doping is found to eliminate the formation of the non-perovskite phase and enhance the crystallinity of the films. Rb-doping is studied under different excess PbI2 concentrations and the optimal condition is found to be 5% Rb-doping and 15% excess PbI2 concentration. The addition of more than 10% Rb results in the formation of an unwanted Rb-rich phase due to the significant lattice mismatch between Rb and FA/MA cations. An efficiency of 18.8% is achieved for the champion cell as compared to 16% with control cells. Importantly, Rb-doping improves the light, moisture and thermal stability of perovskite cells. The optimal bandgap of the perovskite top cell in perovskite-silicon tandems is between 1.7 eV and 1.8 eV. A quadruple-cation Rb/Cs/FA/MA mixed-halide I/Br perovskite composition is explored to obtain high quality perovskite films with a bandgap of 1.73 eV. The ratio between Cs/FA/MA cations is critical to the morphology, crystal orientation and electronic properties of perovskite films. Furthermore, 5% Rb-doping enhances the crystallinity and suppresses defect migration in the films. Semi-transparent cells with efficiencies up to 16% and negligible hysteresis are achieved using this material. With excellent transparency and optimal bandgap of the semi-transparent perovskite cell, a record four-terminal mechanically stacked perovskite-silicon tandem efficiency of 26.4% is achieved.

Data evaluation of trace elements determined in Nigerian coal using cluster procedures.

PubMed

Ewa, I O B

2004-05-01

Large data-sets of elements determined by instrumental neutron activation analysis (INAA) require meaningful interpretation in order to determine the pattern of their existence in host matrices. This could be achieved using cluster procedures. Element abundances (Al, As, Ba, Br, Ca, Ce, Cs, Dy, Eu, Fe, Ga, Gd, Hf, K, La, Lu, Mg, Mn, Na, O, Rb, Sb, Sc, Sm, Sr, Ta, Tb, Th, Ti, U, V, Yb, Zn and Zr) of prepared and run-of-mine coals from eight principal mines (Onyeama, Ogbete, Enugu, Gombe, Asaba-Ugwashi, Okaba, Afikpo and Lafia ) in Nigeria were determined by INAA. Quality control of the measurements was assured by the re-determination of a standard reference material, NIST 1632a. These data-sets were then tested for multi-variate statistics using METHOD = SINGLE in the cluster procedure. The computer-assisted package SAS was used to generate the dendrograms while the algorithm used was stored Euclidean distances. The results showed a recognition pattern, useful for the interpretation of coalification histories and the prediction of fuel ranking for Nigerian coals. High segregation of coal fly ash was observed, while metallurgical coal grouped together with high-ranking coals of Okaba, Enugu and Obi (Lafia). Further work revealed some of these coals as having high gross calorific value (7908 kcal kg(-1) for Enugu coal; 7200 kcal kg(-1) for Okaba) and low sulphur thereby making them efficient fuel materials.

Simultaneous flow of water and solutes through geological membranes-I. Experimental investigation

USGS Publications Warehouse

Kharaka, Y.K.; Berry, F.A.P.

1973-01-01

The relative retardation by geological membranes of cations and anions generally present in subsurface waters was investigated using a high pressure and high temperature 'filtration cell'. The solutions were forced through different clays and a disaggregated shale subjected to compaction pressures up to 9500 psi and to temperatures from 20 to 70??C. The overall efficiences measured increased with increase of exchange capacity of the material used and with decrease in concentration of the input solution. The efficiency of a given membrane increased with increasing compaction pressure but decreased slightly at higher temperatures for solutions of the same ionic concentration. The results further show that geological membranes are specific for different dissolved species. The retardation sequences varied depending on the material used and on experimental conditions. The sequences for monovalent and divalent cations at laboratory temperatures were generally as follows: Li < Na < NH3 < K < Rb < Cs Mg < Ca < Sr < Ba. The sequences for anions at room temperature were variable, but at 70??C, the sequence was: HCO3 < I < B < SO4 < Cl < Br. Monovalent cations contrary to some field data were generally retarded with respect to divalent cations. The differences in the filtration ratios among the divalent cations were smaller than those between the monovalent cations. The passage rate of B, HCO3, I and NH3 was greatly increased at 70??C. ?? 1973.

Elemental analysis of granite by instrumental neutron activation analysis (INAA) and X-ray fluorescence analysis (XRF).

PubMed

El-Taher, A

2012-01-01

The instrumental neutron activation analysis technique (INAA) was used for qualitative and quantitative analysis of granite samples collected from four locations in the Aswan area in South Egypt. The samples were prepared together with their standards and simultaneously irradiated in a neutron flux of 7×10(11)n/cm(2)s in the TRIGA Mainz research reactor. Gamma-ray spectra from an hyper-pure germanium detector were analyzed. The present study provides the basic data of elemental concentrations of granite rocks. The following elements have been determined Na, Mg, K, Fe, Mn, Sc, Cr, Ti, Co, Zn, Ga, Rb, Zr, Nb, Sn, Ba, Cs, La, Ce, Nd, Sm, Eu, Yb, Lu, Hf, Ta, Th and U. The X-ray fluorescence (XRF) was used for comparison and to detect elements, which can be detected only by XRF such as F, S, Cl, Co, Cu, Mo, Ni, Pb, Se and V. The data presented here are our contribution to understanding the elemental composition of the granite rocks. Because there are no existing databases for the elemental analysis of granite, our results are a start to establishing a database for the Egyptian granite. It is hoped that the data presented here will be useful to those dealing with geochemistry, granite chemistry and related fields. Copyright © 2011 Elsevier Ltd. All rights reserved.

Rugged, portable tungsten coil atomic emission spectrometer.

PubMed

Gu, Jiyan; Oliveira, Silvana R; Donati, George L; Gomes Neto, José Anchieta; Jones, Bradley T

2011-04-01

Tungsten coil atomic emission spectrometry is an ideal technique for field applications because of its simplicity, low cost, low power requirement, and independence from cooling systems. A new, portable, compact design is reported here. The tungsten coil is extracted from an inexpensive 24 V, 250 W commercial light bulb. The coil is housed in a small, aluminum cell. The emission signal exits from a small aperture in the cell, while the bulk of the blackbody emission from the tungsten coil is blocked. The resulting spectra exhibit extremely low background signals. The atomization cell, a single lens, and a hand-held charge coupled device (CCD) spectrometer are fixed on a 1 × 6 × 30 cm ceramic base. The resulting system is robust and easily transported. A programmable, miniature 400 W solid-state constant current power supply controls the temperature of the coil. Fifteen elements are determined with the system (Ba, Cs, Li, Rb, Cr, Sr, Eu, Yb, Mn, Fe, Cu, Mg, V, Al, and Ga). The precision ranges from 4.3% to 8.4% relative standard deviation for repetitive measurements of the same solution. Detection limits are in the 0.04 to 1500 μg/L range. Accuracy is tested using standard reference materials for polluted water, peach leaves, and tomato leaves. For those elements present above the detection limit, recoveries range from 72% to 147%.

Determination of Trace Elements in Edible Nuts in the Beijing Market by ICP-M.

PubMed

Yin, Liang Liang; Tian, Qing; Shao, Xian Zhang; Kong, Xiang Yin; Ji, Yan Qin

2015-06-01

Nuts have received increased attention from the public in recent years as important sources of some essential elements, and information on the levels of elements in edible nuts is useful to consumers. Determination of the elemental distributions in nuts is not only necessary in evaluating the total dietary intake of the essential elements, but also useful in detecting heavy metal contamination in food. The aim of this study was to determine the mineral contents in edible nuts, and to assess the food safety of nuts in the Beijing market. Levels of Li, Cr, Mn, Co, Cu, Zn, As, Se, Rb, Sr, Mo, Cd, Cs, Ba, Pb, Th, and U in 11 types of edible nuts and seeds (macadamia nuts, lotus nuts, pistachios, sunflower seeds, pine nuts, almonds, walnuts, chestnuts, hazelnuts, cashews, and ginkgo nuts) as well as raisins were determined by inductively coupled plasma mass spectrometry (ICP-MS). The accuracy of the method was validated using standard reference materials GBW10014 (cabbage) and GBW10016 (tea). Our results provide useful information for evaluating the levels of trace elements in edible nuts in the Beijing market, will be helpful for improving food safety, and will aid in better protecting consumer interests. Copyright © 2015 The Editorial Board of Biomedical and Environmental Sciences. Published by China CDC. All rights reserved.

Geochemistry of Cretaceous granites from Mianning in the Panxi region, Sichuan Province, southwestern China: Implications for their generation

NASA Astrophysics Data System (ADS)

Xu, Cheng; Huang, Zhilong; Qi, Liang; Fu, Pingqing; Liu, Congqiang; Li, Endong; Guan, Tao

2007-03-01

The Cretaceous granites of Mianning, located in the northern Panxi region, were emplaced after collision of the Tibetan Plateau and Yangtze Block. These granites have very high K 2O + Na 2O, Ga, Zr, Nb, Y, REE (except Eu), and very low MgO, CaO, P 2O 5, and Sr contents relative to M-, I- or S-type granites. Based on the chemical discrimination criteria of Whalen et al . [Whalen, J.B., Currie, K.L., Chappell, B.W., 1987. A-type granites: geochemical characteristics, distribution and petrogenesis. Contributions to Mineralogy and Petrology 95, 407-419], most of them are A-type granites. Moreover, the granites plot in the range of post-collision granites and belong to the A2 type. Elevated initial Sr isotopic ratios (>0.72) suggest their derivation dominantly from a crustal source. These features are consistent with granite formation in a post-orogenic setting, such as after subduction or collision between of the Tibetan Plateau and Yangtze Block. In addition, the granites are characterized by low abundances of Ba, Sr, P, Ti, and Eu, positive correlation between Ba and Eu anomalies, and negative correlation between Rb and K/Rb. Plots of Rb vs. Sr suggest that fractional crystallization affected the final compositions of these granites after melting from a dominantly crustal source. From the late Proterozoic to late Mesozoic, the crustal composition, compared to that of the mantle, appears to have increased in the Panxi region. While the mantle component played an important part in the generation of Cretaceous granites in southeastern China, its influence was relatively minor in the Panxi region. Thus, there was a significant difference in mantle evolution between southeastern China and the Panxi region, which led to different metallogenic processes.

Drift pumice in the Central Indian Ocean Basin: Geochemical evidence

NASA Astrophysics Data System (ADS)

Pattan, J. N.; Mudholkar, A. V.; Jai Sankar, S.; Ilangovan, D.

2008-03-01

Abundant white to light grey-coloured pumice without ferromanganese oxide coating occurs within the Quaternary sediments of the Central Indian Ocean Basin (CIOB). Two distinct groups of pumice are identified from their geochemical composition, which allow one to define two different origins linked to two separate eruptions. One group of pumice is a dacitic type characterized by high Fe, Ti, Mg, Al and Ca with comparatively low contents of Si, rare-earth elements (∑REE, 69 ppm), Rb, Sr, U, Th, Ba, V, Nb, Sc, Mo and Co, which strongly suggest an origin from the 1883 Krakatau eruption. The other group is rhyolitic and is characterized by low contents of Fe, Ti, Mg and Ca and high Si, ∑REE content (121 ppm), Rb, Sr, U, Th, Ba, V, Nb, Mo, Co, and Sc and correlates well with the composition of the Youngest Toba Tuff (YTT) eruption of ˜74 ka from Northern Sumatra and is being reported for the first time. Therefore, correlation of the pumice to the 1883 Krakatau and YTT eruptions indicates that the pumice drifted to the CIOB and eventually sank when it became waterlogged. However, physical properties such as density, specific gravity, porosity and degree of saturation required for sinking of pumice for both 1883 Krakatau and YTT are almost similar.

Origin and evolution of the Nakhla meteorite inferred from the Sm-Nd and U-Pb systematics and REE, Ba, Sr, Rb and K abundances

NASA Technical Reports Server (NTRS)

Nakamura, N.; Unruh, D. M.; Tatsumoto, M.; Hutchison, R.

1982-01-01

Analyses of whole rock and mineral separates from the Nakhla meteorite are carried out by means of Sm-Nd and U-Tn-Pb systematics and by determining their REE, Ba, Sr, Rb, and K concentrations. Results show that the Sm-Nd age of the meteorite is 1.26 + or - 0.7 b.y., while the high initial epsilon(Nd) value of +16 suggests that Nakhla was derived from a light REE-depleted, old planetary mantle source. A three-stage Sm-Nd evolution model is developed and used in combination with LIL element data and estimated partition coefficients in order to test partial melting and fractional crystallization models and to estimate LIL abundances in a possible Nakhla source. The calculations indicate that partial melting of the source followed by extensive fractional crystallization of the partial melt could account for the REE abundances in the Nakhla constituent minerals. It is concluded that the significantly younger age of Nakhla than the youngest lunar rock, the young differentiation age inferred from U-Th-Pb data, and the estimated LIL abundances suggest that this meteorite may have been derived from a relatively large, well-differentiated planetary body such as Mars.

Calculated high-pressure structural properties, lattice dynamics and quasi particle band structures of perovskite fluorides KZnF3, CsCaF3 and BaLiF3

NASA Astrophysics Data System (ADS)

Vaitheeswaran, G.; Kanchana, V.; Zhang, Xinxin; Ma, Yanming; Svane, A.; Christensen, N. E.

2016-08-01

A detailed study of the high-pressure structural properties, lattice dynamics and band structures of perovskite structured fluorides KZnF3, CsCaF3 and BaLiF3 has been carried out by means of density functional theory. The calculated structural properties including elastic constants and equation of state agree well with available experimental information. The phonon dispersion curves are in good agreement with available experimental inelastic neutron scattering data. The electronic structures of these fluorides have been calculated using the quasi particle self-consistent GW approximation. The GW calculations reveal that all the fluorides studied are wide band gap insulators, and the band gaps are significantly larger than those obtained by the standard local density approximation, thus emphasizing the importance of quasi particle corrections in perovskite fluorides.

Calculated high-pressure structural properties, lattice dynamics and quasi particle band structures of perovskite fluorides KZnF3, CsCaF3 and BaLiF3.

PubMed

Vaitheeswaran, G; Kanchana, V; Zhang, Xinxin; Ma, Yanming; Svane, A; Christensen, N E

2016-08-10

A detailed study of the high-pressure structural properties, lattice dynamics and band structures of perovskite structured fluorides KZnF3, CsCaF3 and BaLiF3 has been carried out by means of density functional theory. The calculated structural properties including elastic constants and equation of state agree well with available experimental information. The phonon dispersion curves are in good agreement with available experimental inelastic neutron scattering data. The electronic structures of these fluorides have been calculated using the quasi particle self-consistent [Formula: see text] approximation. The [Formula: see text] calculations reveal that all the fluorides studied are wide band gap insulators, and the band gaps are significantly larger than those obtained by the standard local density approximation, thus emphasizing the importance of quasi particle corrections in perovskite fluorides.

Evolution of deformation in neutron-rich Ba isotopes up to A =150

NASA Astrophysics Data System (ADS)

Licǎ, R.; Benzoni, G.; Rodríguez, T. R.; Borge, M. J. G.; Fraile, L. M.; Mach, H.; Morales, A. I.; Madurga, M.; Sotty, C. O.; Vedia, V.; De Witte, H.; Benito, J.; Bernard, R. N.; Berry, T.; Bracco, A.; Camera, F.; Ceruti, S.; Charviakova, V.; Cieplicka-Oryńczak, N.; Costache, C.; Crespi, F. C. L.; Creswell, J.; Fernandez-Martínez, G.; Fynbo, H.; Greenlees, P. T.; Homm, I.; Huyse, M.; Jolie, J.; Karayonchev, V.; Köster, U.; Konki, J.; Kröll, T.; Kurcewicz, J.; Kurtukian-Nieto, T.; Lazarus, I.; Lund, M. V.; Mǎrginean, N.; Mǎrginean, R.; Mihai, C.; Mihai, R. E.; Negret, A.; Orduz, A.; Patyk, Z.; Pascu, S.; Pucknell, V.; Rahkila, P.; Rapisarda, E.; Regis, J. M.; Robledo, L. M.; Rotaru, F.; Saed-Samii, N.; Sánchez-Tembleque, V.; Stanoiu, M.; Tengblad, O.; Thuerauf, M.; Turturica, A.; Van Duppen, P.; Warr, N.; IDS Collaboration

2018-02-01

The occurrence of octupolar shapes in the Ba isotopic chain was recently established experimentally up to N =90 . To further extend the systematics, the evolution of shapes in the most neutron-rich members of the Z =56 isotopic chain accessible at present, Ba,150148, has been studied via β decay at the ISOLDE Decay Station. This paper reports on the first measurement of the positive- and negative-parity low-spin excited states of 150Ba and presents an extension of the β -decay scheme of 148Cs. Employing the fast timing technique, half-lives for the 21+ level in both nuclei have been determined, resulting in T1 /2=1.51 (1 ) ns for 148Ba and T1 /2=3.4 (2 ) ns for 150Ba. The systematics of low-spin states, together with the experimental determination of the B (E 2 :2+→0+) transition probabilities, indicate an increasing collectivity in Ba-150148, towards prolate deformed shapes. The experimental data are compared to symmetry conserving configuration mixing (SCCM) calculations, confirming an evolution of increasingly quadrupole deformed shapes with a definite octupolar character.

Heavy ion irradiations on synthetic hollandite-type materials: Ba1.0Cs0.3A2.3Ti5.7O16 (A=Cr, Fe, Al)

NASA Astrophysics Data System (ADS)

Tang, Ming; Tumurugoti, Priyatham; Clark, Braeden; Sundaram, S. K.; Amoroso, Jake; Marra, James; Sun, Cheng; Lu, Ping; Wang, Yongqiang; Jiang, Ying.-Bing.

2016-07-01

The hollandite supergroup of minerals has received considerable attention as a nuclear waste form for immobilization of Cs. The radiation stability of synthetic hollandite-type compounds described generally as Ba1.0Cs0.3A2.3Ti5.7O16 (A=Cr, Fe, Al) were evaluated by heavy ion (Kr) irradiations on polycrystalline single phase materials and multiphase materials incorporating the hollandite phases. Ion irradiation damage effects on these samples were examined using grazing incidence X-ray diffraction (GIXRD) and transmission electron microscopy (TEM). Single phase compounds possess tetragonal structure with space group I4/m. GIXRD and TEM observations revealed that 600 keV Kr irradiation-induced amorphization on single phase hollandites compounds occurred at a fluence between 2.5×1014 Kr/cm2 and 5×1014 Kr/cm2. The critical amorphization fluence of single phase hollandite compounds obtained by in situ 1 MeV Kr ion irradiation was around 3.25×1014 Kr/cm2. The hollandite phase exhibited similar amorphization susceptibility under Kr ion irradiation when incorporated into a multiphase system.

Preliminary Reports, Memoranda and Technical Notes of the Materials Research Council Summer Conference, La Jolla, California

DTIC Science & Technology

1986-07-01

also known. 27 For Li, Na, K, Rb, and Cs plus C02, one observes 28,29 species like -N [M+ , C021, [ M+ , (C02 )2"] and, ultimately, the metal oxalate ...many opportunities for significant research on hydrothermal processes, e.g., the preparation of clean oxide powders for ceramic uses. We believe the high

Preparation of Chitosan Coated Magnetic Hydroxyapatite Nanoparticles and Application for Adsorption of Reactive Blue 19 and Ni2+ Ions

PubMed Central

Nguyen, Van Cuong; Pho, Quoc Hue

2014-01-01

An adsorbent called chitosan coated magnetic hydroxyapatite nanoparticles (CS-MHAP) was prepared with the purpose of improvement for the removal of Ni2+ ions and textile dye by coprecipitation. Structure and properties of CS-MHAP were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and vibrating sample magnetometer (VSM). Weight percent of chitosan was investigated by thermal gravimetric analysis (TGA). The prepared CS-MHAP presents a significant improvement on the removal efficiency of Ni2+ ions and reactive blue 19 dye (RB19) in comparison with chitosan and magnetic hydroxyapatite nanoparticles. Moreover, the adsorption capacities were affected by several parameters such as contact time, initial concentration, adsorbent dosage, and initial pH. Interestingly, the prepared adsorbent could be easily recycled from an aqueous solution by an external magnet and reused for adsorption with high removal efficiency. PMID:24592158

Luminescence of the elpasolite series MI2MIIMCl6 (MI=Cs, Rb; MII=Li, Na; M=Lu, Y, Sc, In) doped with europium using synchrotron radiation excitation

NASA Astrophysics Data System (ADS)

Tanner, Peter A.; Duan, Chang-Kui; Jia, Guohua; Cheng, Bing-Ming

2012-04-01

The excitation and emission spectra of a series of cubic hexachloroelpasolites doped with europium have been investigated using synchrotron radiation at 10 K. Besides the Eu3+ emission from 5DJ (J=0-3) multiplets, emission from 5H3 is also observed for Cs2NaIn0.995Eu0.005Cl6, since the gap to the next lowest level is spanned by seven phonons. The excitation spectra of samples indicate impurities due to oxygen and divalent europium. Broad band emission from Eu2+ is reported from the crystalline samples grown in vacuum by the Bridgman process, with the maximum wavelength shifting to the red with increasing lattice parameter for the series Cs2NaMCl6:Eu2+ (M=Lu, Y, Eu).

Structural and magnetic properties of spark plasma sintered Co-Mg-Zn substituted Ba-Sr hexagonal ferrite magnets

NASA Astrophysics Data System (ADS)

Harikrishnan, V.; Vizhi, R. Ezhil; Rajan Babu, D.; Saravanan, P.

2018-02-01

The effect of conventional and spark plasma sintering processes on the structural and magnetic properties of Ba0.5Sr0.5Fe12-2xCox(MgZn)x/2O19 (x = 0.2, 0.4 and 0.6) was investigated in this study. XRD patterns of both conventionally sintered (CS) and spark plasma sintered (SPS) samples with x = 0.2 and 0.4 showed the crystallization of Ba0.5Sr0.5Fe12O19-phase with space group of P63/mmc. However, in the case of SPS sample with x = 0.4, a secondary peak of α-Fe2O3 was observed. SEM analysis on the SPS samples revealed dense morphology with low porosity; while the CS samples showed the presence of aggregated particles with spherical shapes. Maximum values of saturation magnetization, MS (58 emu/g) and coercivity, HC (3.5 kOe) were obtained for the CS samples with x = 0.4; while their SPS counterparts revealed increased MS (65 emu/g) and HC (3.9 kOe) values. The observed magnetization reversal behaviour for both sintering conditions were not smooth in the case of x = 0.2, which indicated the existence of two-phase behavior. The temperature dependent magnetization studies for x = 0.2 and 0.4 were performed in order to analyze the variation in Curie temperature against Co-Mg-Zn substitution and the obtained results are discussed on the basis of crystallization of hexaferrite-phase.

Tracing subduction zone fluid-rock interactions using trace element and Mg-Sr-Nd isotopes

NASA Astrophysics Data System (ADS)

Wang, Shui-Jiong; Teng, Fang-Zhen; Li, Shu-Guang; Zhang, Li-Fei; Du, Jin-Xue; He, Yong-Sheng; Niu, Yaoling

2017-10-01

Slab-derived fluids play a key role in mass transfer and elemental/isotopic exchanges in subduction zones. The exhumation of deeply subducted crust is achieved via a subduction channel where fluids from various sources are abundant, and thus the chemical/isotopic compositions of these rocks could have been modified by subduction-zone fluid-rock interactions. Here, we investigate the Mg isotopic systematics of eclogites from southwestern Tianshan, in conjunction with major/trace element and Sr-Nd isotopes, to characterize the source and nature of fluids and to decipher how fluid-rock interactions in subduction channel might influence the Mg isotopic systematics of exhumed eclogites. The eclogites have high LILEs (especially Ba) and Pb, high initial 87Sr/86Sr (up to 0.7117; higher than that of coeval seawater), and varying Ni and Co (mostly lower than those of oceanic basalts), suggesting that these eclogites have interacted with metamorphic fluids mainly released from subducted sediments, with minor contributions from altered oceanic crust or altered abyssal peridotites. The positive correlation between 87Sr/86Sr and Pb* (an index of Pb enrichment; Pb* = 2*PbN/[CeN + PrN]), and the decoupling relationships and bidirectional patterns in 87Sr/86Sr-Rb/Sr, Pb*-Rb/Sr and Pb*-Ba/Pb spaces imply the presence of two compositionally different components for the fluids: one enriched in LILEs, and the other enriched in Pb and 87Sr/86Sr. The systematically heavier Mg isotopic compositions (δ26Mg = - 0.37 to + 0.26) relative to oceanic basalts (- 0.25 ± 0.07) and the roughly negative correlation of δ26Mg with MgO for the southwestern Tianshan eclogites, cannot be explained by inheritance of Mg isotopic signatures from ancient seafloor alteration or prograde metamorphism. Instead, the signatures are most likely produced by fluid-rock interactions during the exhumation of eclogites. The high Rb/Sr and Ba/Pb but low Pb* eclogites generally have high bulk-rock δ26Mg values, whereas high Pb* and 87Sr/86Sr eclogites have mantle-like δ26Mg values, suggesting that the two fluid components have diverse influences on the Mg isotopic systematics of these eclogites. The LILE-rich fluid component, possibly derived from mica-group minerals, contains a considerable amount of isotopically heavy Mg that has shifted the δ26Mg of the eclogites towards higher values. By contrast, the 87Sr/86Sr- and Pb-rich fluid component, most likely released from epidote-group minerals in metasediments, has little Mg so as not to modify the Mg isotopic composition of the eclogites. In addition, the influence of talc-derived fluid might be evident in a very few eclogites that have low Rb/Sr and Ba/Pb but slightly heavier Mg isotopic compositions. These findings represent an important step toward a broad understanding of the Mg isotope geochemistry in subduction zones, and contributing to understanding why island arc basalts have averagely heavier Mg isotopic compositions than the normal mantle.

Nuclear Data Sheets for A = 142

NASA Astrophysics Data System (ADS)

Johnson, T. D.; Symochko, D.; Fadil, M.; Tuli, J. K.

2011-08-01

The 2000 Nuclear Data Sheets for A=142 by J. K. Tuli, with literature cutoff date of February 4, 2000, has been revised. The evaluated experimental data are presented for 16 known nuclides of mass 142 (Ba, Ce, Cs, Dy, Eu, Gd, Ho, I, La, Nd, Pm, Pr, Sm, Tb, Te, Xe). Comparing to the previous evaluation (2000Tu01) significant changes were done to the level schemes of Gd, Cs, Ce and Nd. For all nuclides, the more recent Q values have been added.

Nuclear Data Sheets for A-142

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

Johnson, T.D.; Johnson,T.D.; Symochko,D.

The 2000 Nuclear Data Sheets for A = 142 by J. K. Tuli, with literature cutoff date of February 4, 2000, has been revised. The evaluated experimental data are presented for 16 known nuclides of mass 142 (Ba, Ce, Cs, Dy, Eu, Gd, Ho, I, La, Nd, Pm, Pr, Sm, Tb, Te, Xe). Comparing to the previous evaluation (2000Tu01) significant changes were done to the level schemes of Gd, Cs, Ce and Nd. For all nuclides, the more recent Q values have been added.

Surface area of montmorillonite from the dynamic sorption of nitrogen and carbon dioxide

USGS Publications Warehouse

Thomas, Josephus; Bohor, Bruce F.

1968-01-01

Surface area determinations were made on a montmorillonite with various cations emplaced on the exchangeable sites, utilizing nitrogen and carbon dioxide as adsorbates at 77°K and 195°K, respectively, in a dynamic system. From the fraction of a Mississippi montmorillonite less than about 1 μ in size, samples were prepared by replacing the original exchangeable cations with Li+, Na+, K+, Rb+, Cs+, Mg++, Ca++, Ba++, and NH4+, forming a series of homoionic montmorillonite species.Surface areas from 3-point B.E.T. plots (half-hour adsorption points), with nitrogen as the adsorbate, ranged from 61 m2/g for Li-montmorillonite to 138 m2/g for Cs-montmorillonite, thus reflecting a certain degree of nitrogen penetration between layers. Complete penetration should theoretically result in a surface area of over 300 m2/g for this clay with a nitrogen monolayer between each pair of platelets. The experimental data indicate that the extent of penetration is time-dependent and is also a function of the interlayer forces as governed by the size and charge of the replaceable cation. This finding negates the generally accepted concept that nitrogen at 77°K does not penetrate the layers and provides a measure only of the external surface of expandable clay minerals.A further measure of the variation of interlayer forces is provided by the adsorption of carbon dioxide at 195°K. Surface area values ranged from 99 m2/g for Li-montmorillonite to 315 m2/g for Csmontmorillonite. Although the carbon dioxide molecule is larger than the nitrogen molecule, its greater penetration apparently is a result of its being kinetically more energetic (with a larger diffusion coefficient) at its higher adsorption temperature. Similar differences have been found with both adsorbates in the study of microporous substances, such as coal, where activated diffusion is of considerable significance.

Ionic selectivity of native ATP-activated (P2X) receptor channels in dissociated neurones from rat parasympathetic ganglia

PubMed Central

Liu, Dong-Mei; Adams, David J

2001-01-01

The relative permeability of the native P2X receptor channel to monovalent and divalent inorganic and organic cations was determined from reversal potential measurements of ATP-evoked currents in parasympathetic neurones dissociated from rat submandibular ganglia using the dialysed whole-cell patch clamp technique. The P2X receptor-channel exhibited weak selectivity among the alkali metals with a selectivity sequence of Na+ > Li+ > Cs+ > Rb+ > K+, and permeability ratios relative to Cs+ (PX/PCs) ranging from 1.11 to 0.86. The selectivity for the divalent alkaline earth cations was also weak with the sequence Ca2+ > Sr2+ > Ba2+ > Mn2+ > Mg2+. ATP-evoked currents were strongly inhibited when the extracellular divalent cation concentration was increased. The calculated permeability ratios of different ammonium cations are higher than those of the alkali metal cations. The permeability sequence obtained for the saturated organic cations is inversely correlated with the size of the cation. The unsaturated organic cations have a higher permeability than that predicted by molecular size. Acidification to pH 6.2 increased the ATP-induced current amplitude twofold, whereas alkalization to 8.2 and 9.2 markedly reduced current amplitude. Cell dialysis with either anti-P2X2 and/or anti-P2X4 but not anti-P2X1 antibodies attenuated the ATP-evoked current amplitude. Taken together, these data are consistent with homomeric and/or heteromeric P2X2 and P2X4 receptor subtypes expressed in rat submandibular neurones. The permeability ratios for the series of monovalent organic cations, with the exception of unsaturated cations, were approximately related to the ionic size. The relative permeabilities of the monovalent inoganic and organic cations tested are similar to those reported previously for cloned rat P2X2 receptors expressed in mammalian cells. PMID:11454961

First-principles study of paraelectric and ferroelectric CsH2PO4 including dispersion forces: Stability and related vibrational, dielectric, and elastic properties

NASA Astrophysics Data System (ADS)

Van Troeye, Benoit; van Setten, Michiel Jan; Giantomassi, Matteo; Torrent, Marc; Rignanese, Gian-Marco; Gonze, Xavier

2017-01-01

Using density functional theory (DFT) and density functional perturbation theory (DFPT), we investigate the stability and response functions of CsH2PO4 , a ferroelectric material at low temperature. This material cannot be described properly by the usual (semi)local approximations within DFT. The long-range e--e- correlation needs to be properly taken into account, using, for instance, Grimme's DFT-D methods, as investigated in this work. We find that DFT-D3(BJ) performs the best for the members of the dihydrogenated alkali phosphate family (KH2PO4 , RbH2PO4 , CsH2PO4 ), leading to experimental lattice parameters reproduced with an average deviation of 0.5%. With these DFT-D methods, the structural, dielectric, vibrational, and mechanical properties of CsH2PO4 are globally in excellent agreement with the available experiments (<2 % MAPE for Raman-active phonons). Our study suggests the possible existence of a new low-temperature phase of CsH2PO4 , not yet reported experimentally. Finally, we report the implementation of DFT-D contributions to elastic constants within DFPT.

Genesis of post-collisional calc-alkaline and alkaline granitoids in Qiman Tagh, East Kunlun, China

NASA Astrophysics Data System (ADS)

Yu, Miao; Feng, Chengyou; Zhao, Yiming; Li, Daxin

2015-12-01

The post-collisional magmatism of Qiman Tagh is characterized by the intrusion of voluminous intermediate to felsic granitoids, including syenogranite, monzogranite, granodiorite, tonalite and diorite. The granitoids can be divided into two magmatic suites: Calc-alkaline (CA) and alkaline (Alk), which were emplaced from ~ 236 Ma to ~ 204 Ma. The CA suite contains metaluminous granodiorites and monzogranites. Typical Qiman Tagh CA granodiorites show moderately fractionated REE patterns ((La/Yb)N = 4.35-25.11) with significant negative Eu anomalies (Eu/Eu* = 0.54-1.34), and the primitive mantle-normalized spidergrams show strong depletion of Nb and Sr. The Qiman Tagh CA monzogranites show similar fractionated REE patterns ((La/Yb)N = 2.70-13.5) with less prominent negative Eu anomalies, and the chondrite-normalized spidergrams show strongly depleted Ba, Nb and Sr. The Alk suite, including syenogranite, is highly potassic (K2O/Na2O = 1.09-3.56) and peraluminous (A/CNK = 0.91-1.06). Compared to typical Qiman Tagh CA granodiorites, the Qiman Tagh Alk granitoids can be distinguished by their higher Rb, Nb, Ga/Al, FeO*/MgO, Y/Sr and Rb/Sr, as well as their lower Mg#, MgO, CaO, Al2O3, Sr, Co, V, Eu/Eu*, Ba/Nb, La/Nb, Ba/La and Ce/Nb. The Qiman Tagh CA rocks were most likely to be derived from the partial melting of garnet-amphibolite-facies rocks in the lower crust, leaving behind anhydrous granulite-facies rocks with plagioclase and garnet in the residue. The Alk rocks may have formed by the continued partial melting of granulite-facies rocks at elevated temperatures (> 830 °C).

Elemental Characteristics of Australian Sedimentary Opals and their Implications for Opal Formation and Gemstone Fingerprinting

NASA Astrophysics Data System (ADS)

Dutkiewicz, A.; Landgrebe, T. C.; Rey, P. F.

2011-12-01

Opal consists of amorphous SiO2.nH2O comprising a network of silica spheres, which in precious opal are of similar size and form an ordered network allowing light to diffract into an array of colors. Common opal, which is often associated with precious opal, lacks this play of color as it is composed of silica spheres of variable sizes. Australia supplies over 95% of the world's precious opal. The opal is almost exclusively located within Cretaceous sedimentary rocks of the Great Artesian Basin, which experienced a major phase of uplift in the Late Cretaceous with subsequent erosion removing a package of sedimentary rock up to 3 km in thickness. Intense weathering resulted in extensive silicification at relatively shallow levels within the Tertiary regolith. However, despite a billion dollar industry and a well-constrained geological history of the basin, the formation of sedimentary opal and its uniqueness to the Australian continent are still very poorly understood. In this study we have used laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) on precious and common opal from key opal mining areas in order to constrain the possible sources of silica fluids involved in opal genesis and to assess whether any major or trace elements could be used to determine the provenance of opal with respect to a particular mining area. A total of 123 spots, each comprising 59 elements, including rare earth elements were analyzed. Globally, volcanic and sedimentary opals can be distinguished on the basis of Ba and Ca concentrations. Although the opals from the Great Artesian Basin are all sedimentary, some show Ba concentrations consistent with volcanic opals suggesting that silica fluids from which they formed were derived from a volcanic province. The most likely source is the Cretaceous volcanic-plutonic province of central Queensland, which supplied vast amounts of volcanogenic material into the Great Artesian Basin. The weathering of feldspars from the volcaniclastic rocks would have provided ample silica-rich fluids for the formation of opal as well as kaolinite, which is abundant within the opal host rocks. Multivariate feature-selection analysis (using a signal-to-noise criterion) of elemental concentrations in opal bands from different locations indicates that the mining region from which the opals originate can best be discriminated using a combination of K, Se and Hf. The best independent provenance discriminators are K, Rb, Ba, Cs and Hf. Precious and common opal can be discriminated using a combination of Th, Hf and Cs with the best independent discriminators being Th, Bi and La. Overall, Th is the best element by which to discriminate between precious and common opals as these are characterized by relatively low and relatively high concentrations of Th, respectively. In general, major and trace element concentrations are significantly higher in common opals than in precious ones. Precious opal color is very difficult to discriminate based on elemental concentrations as it depends on the size and ordering of spheres. However, brown common opal can be distinguished from grey common opal based on concentrations of Pb, Ba and Fe. Opal fingerprinting is therefore possible using just a small number of elements.

Comparative study of A-site order in the lead-free bismuth titanates M{sub 1/2}Bi{sub 1/2}TiO{sub 3} (M=Li, Na, K, Rb, Cs, Ag, Tl) from first-principles

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

Gröting, Melanie, E-mail: groeting@mm.tu-darmstadt.de; Albe, Karsten, E-mail: albe@mm.tu-darmstadt.de

2014-05-01

We investigate the possibility of enhancing chemical order in the relaxor ferroelectric Na{sub 1/2}Bi{sub 1/2}TiO{sub 3} upon substitution of Na{sup +} by other monovalent cations M{sup +} using total energy calculations based on density functional theory. All chemically available monovalent cations M{sup +}, which are Li, Na, Ag, K, Tl, Rb and Cs, are considered and an analysis of the structurally relaxed structures in terms of symmetry-adapted distortion modes is given in order to quantify the chemically induced structural distortions. We demonstrate that the replacement of Na{sup +} by other monovalent cations can hardly alter the tendency of chemical ordermore » with respect to Na{sub 1/2}Bi{sub 1/2}TiO{sub 3}. Only Tl{sub 1/2}Bi{sub 1/2}TiO{sub 3} and Ag{sub 1/2}Bi{sub 1/2}TiO{sub 3} show enhanced tendency for chemical ordering. Both heavy metals behave similar to the light alkali metals in terms of structural relaxations and relative stabilities of the ordered configurations. Although a comparison of the Goldschmidt factors of components (M TiO{sub 3}){sup −} reveals for Tl a value above the upper stability limit for perovskites, the additional lone-pair effect of Tl{sup +} stabilizes the ordered structure. - Graphical abstract: Amplitudes of chemically induced distortion modes in different ordered perovskites M{sub 1/2}Bi{sub 1/2}TiO{sub 3} and visualisation of atomic displacements associated with distortion mode X{sup +}{sub 1} in the 001-ordered compounds Li{sub 1/2}Bi{sub 1/2}TiO{sub 3} and Cs{sub 1/2}Bi{sub 1/2}TiO{sub 3}. Due to a substantial size mismatch between bismuth (green) and caesium (dark blue), incorporation of the latter leads to enhanced displacements of oxygen atoms (red) and suppresses displacements of titanium (silver) as compared to lithium (light blue) or other smaller monovalent cations. - Highlights: • Lead-free A-site mixed bismuth titanates M{sub 1/2}Bi{sub 1/2}TiO{sub 3} are studied by first-principles calculations. • Investigation of chemical ordering tendency for M=Li, Na, K, Rb, Cs, Ag, and Tl. • Group theoretical analysis of different ordered structures. • Ag and Tl compounds are the most promising candidates for study of chemical order dependent ferroelectric properties.« less

Ultramafic clasts from the South Chamorro serpentine mud volcano reveal a polyphase serpentinization history of the Mariana forearc mantle

NASA Astrophysics Data System (ADS)

Kahl, Wolf-Achim; Jöns, Niels; Bach, Wolfgang; Klein, Frieder; Alt, Jeffrey C.

2015-06-01

Serpentine seamounts located on the outer half of the pervasively fractured Mariana forearc provide an excellent window into the forearc devolatilization processes, which can strongly influence the cycling of volatiles and trace elements in subduction zones. Serpentinized ultramafic clasts recovered from an active mud volcano in the Mariana forearc reveal microstructures, mineral assemblages and compositions that are indicative of a complex polyphase alteration history. Petrologic phase relations and oxygen isotopes suggest that ultramafic clasts were serpentinized at temperatures below 200 °C. Several successive serpentinization events represented by different vein generations with distinct trace element contents can be recognized. Measured in situ Rb/Cs ratios are fairly uniform ranging between 1 and 10, which is consistent with Cs mobilization from sediments at lower temperatures and lends further credence to the low-temperature conditions proposed in models of the thermal structure in forearc settings. Late veins show lower fluid mobile element (FME) concentrations than early veins, suggesting a decreasing influence of fluid discharge from the subducting slab on the composition of the serpentinizing fluids. The continuous microfabric and mineral chemical evolution observed in the ultramafic clasts may have implications as to the origin and nature of the serpentinizing fluids. We hypothesize that opal and smectite dehydration produce quartz-saturated fluids with high FME contents and Rb/Cs between 1 and 4 that cause the early pervasive serpentinization. The partially serpentinized material may then be eroded from the basal plane of the suprasubduction mantle wedge. Serpentinization continued but the interacting fluids did not carry a pronounced sedimentary signature, either because FMEs were no longer released from the slab, or due to an en route loss of FMEs. Late chrysotile veins that document the increased access of fluids in a now fluid-dominated regime are characterized by reduced trace element contents with a slightly increased Rb/Cs ratio near 10. This lack of sediment-dominated geochemical signatures consistently displayed in all late serpentinization stages may indicate that the sediment-derived fluids have been completely reset (i.e. the FME excesses were removed) by continued water-rock reaction within the subduction channel. The final stage of buoyant rise of matrix and clasts in the conduits is characterized by brucite-dominated alteration of the clasts from the clast rim inward (independent of the intra-clast fabric relations), which corresponds to re-equilibration with alkaline, low-silica activity fluids in the rising mud.

Prospective Analyses of Hormone Levels, Alcohol Intake, and Body Fat Distribution in Relation to Breast Cancer Risk

DTIC Science & Technology

1998-07-01

for reproducibility and validity (40,41). More extensive dietary questionnaires were included in the 1984, 1986, and 1990 follow-up; over 80 nutritional ...DJH, RB, FES); Departments of Epidemiology (SEH, WCW, JEM, GAC, DJH, DS) Environmental Health (FES), Nutrition (WCW), and Biostatistics (DS), Harvard...McDermott A, Rosner BA. Regression calibration methods for correcting measurement-error bias in nutritional epidemiology. Am J Clin Nutr 1997; 65

Trace elements in primitive meteorites—VII Antarctic unequilibrated ordinary chondrites

NASA Astrophysics Data System (ADS)

Wang, Ming-Sheng; Lipschutz, Michael E.

2007-02-01

We report RNAA results for Co, Au, Sb, Ga, Rb, Cs, Se, Ag, Te, Zn, In, Bi, Tl and Cd (in increasing order of metamorphic mobility) in 22 Antarctic unequilibrated ordinary chondrites (UOC). This brings to 38 the number of UOC for which data for highly volatile elements are known. For elements of lesser mobility (Co to Se, omitting Cs) overall variability in UOC are low, relative standard deviations (one sigma) being no more than a factor of two. For Ag, Te and Zn, relative standard deviations are 2-4×, while for Cs and the four most volatile elements, the variabilities are 8-110×. Elemental abundances do not vary with chemical type (H, L and LL) nor with UOC subtype (3.0-3.9). Contents of all elements reach levels up to, even exceeding, cosmic and all but Cd and the two alkalis, seem unaffected by post-accretionary processes. Contents of highly volatile elements are consistent with the idea that source regions producing contemporary falls and older Antarctic UOC differed in thermal histories. The presence or absence of carbide magnetite assemblages (CMA) generally accords with high or low Cd contents, respectively. This relationship accords with the prior suggestion that CMA formed by alteration of Fe-Ni metal by C-O-H-containing fluids at temperatures <700 K, generated by thermal metamorphism in parent body interiors. The absence of CMA in most UOC (and OC), may indicate that they were subsequently destroyed as metamorphic intensity increased. The high, often supercosmic, Rb and Cs levels in UOC may result from their high solubility in liquid water signalling their redistribution by C-O-H-containing fluid while in the liquid water field. Because of its uniquely high mobility, Cd could have been enriched by the C-O-H fluids and should have been lost from parent regions during later, higher temperature anhydrous metamorphism at temperatures in the 500-600 °C range.

Levels of eight trace elements in edible mushrooms from a rural area.

PubMed

Svoboda, Lubomír; Chrastný, Vladislav

2008-01-01

Eight trace elements were determined using ICP-MS in 78 fruiting body samples of 22 edible mushroom species. The mushrooms were collected from four sites in a rural area, unpolluted by human activity. Median values (dry matter) were as follows: Arsenic (As) 1.45 mg kg(-1), barium (Ba) 1.41 mg kg(-1), cobalt (Co) 0.28 mg kg(-1), copper (Cu) 47.0 mg kg(-1), rubidium (Rb) 130 mg kg(-1), silver (Ag) 2.95 mg kg(-1), thallium (Tl) 0.02 mg kg(-1) and vanadium (V) 0.25 mg kg(-1). Higher trace element accumulation was observed in samples of Macrolepiota procera, Macrolepiota rhacodes, Lycoperdon perlatum, Lycoperdon gigantea and Xerocomus chrysenteron for As and Cu, and in samples of Cantharellus cibarius and of genera Boletus and Suillus for Rb.

Luna 16 - Some Li, K, Rb, Sr, Ba, rare-earth, Zr, and Hf concentrations.

NASA Technical Reports Server (NTRS)

Philpotts, J. A.; Schnetzler, C. C.; Schuhmann, S.; Thomas , H. H.; Bottino, M. L.

1972-01-01

Concentrations of Li, K, Rb, Sr, Na, rare-earths, Zr and Hf have been determined for some Luna 16 core materials by mass-spectrometric isotope-dilution. Two regolith fines samples from different depths in the core, and four rock-chips, including both igneous rocks and breccias, have similar trace-element concentrations. The Luna 16 materials have general lunar trace-element characteristics but differ from other returned lunar samples in a manner that suggests the presence of excess feldspar. Unless the Luna 16 igneous rocks are fused soils, they appear to represent either partial plagioclase cumulates or the least differentiated igneous material yet returned from the moon. The similarity in trace-element concentrations of the igneous rocks and the fines would then suggest largely local derivation of the Luna 16 regolith.

The Determination of Soil-plant Transfer Coefficients of Cesium-137 and Other Elements by γ-Ray Measurement and PIXE Analysis, for use in the Remediation of Fukushima

NASA Astrophysics Data System (ADS)

Ishii, K.; Fujita, A.; Toyama, S.; Terakawa, A.; Matsuyama, S.; Arai, H.; Osada, N.; Takyu, S.; Matsuyama, T.; Koshio, S.; Watanabe, K.; Ito, S.; Kasahara, K.

Edible wild plants growing in the area around the Fukushima Daiichi nuclear power plant remain contaminated. It is important to identify plants with low levels of contamination for the restoration of agriculture in the area. We collected specimens of 10 wild plant species growing in Iitate village which is one of the most highly contaminated areas and also sampled the soil beneath each plant. We measured the specific activity of 137Cs and the concentrations of Na, Mg, Al, Si, P, S, K, Ca, Fe, Zn, Rb and Sr in these samples using a germanium detector and PIXE analysis, respectively. We compared the soil-plant transfer coefficient of 137Cs with those of each element and determined their correlation with 137Cs. It was found that a low Sr transfer coefficient could be used to determine the plants with a low 137Cs transfer coefficient. We suggest that PIXE analysis is a useful analysis technique for agricultural remediation projects in highly contaminated areas around the Fukushima Daiichi nuclear power plant.

Relativistic Corrections to the Properties of the Alkali Fluorides

NASA Technical Reports Server (NTRS)

Dyall, Kenneth G.; Partridge, Harry

1993-01-01

Relativistic corrections to the bond lengths, dissociation energies and harmonic frequencies of KF, RbF and CsF have been obtained at the self-consistent field level by dissociating to ions. The relativistic corrections to the bond lengths, harmonic frequencies and dissociation energies to the ions are very small, due to the ionic nature of these molecules and the similarity of the relativistic and nonrelativistic ionic radii.

Origin discrimination of defatted pork via trace elements profiling, stable isotope ratios analysis, and multivariate statistical techniques.

PubMed

Park, Yu Min; Lee, Cheong Mi; Hong, Joon Ho; Jamila, Nargis; Khan, Naeem; Jung, Jong-Hyun; Jung, Young-Chul; Kim, Kyong Su

2018-09-01

This study verified the origin of 346 defatted Korean and non-Korean pork samples via trace elements profiling, and C and N stable isotope ratios analysis. The analyzed elements were 6 Li, 7 Li, 10 B, 11 B, 51 V , 50 Cr, 52 Cr, 53 Cr, 55 Mn, 58 Ni, 60 Ni, 59 Co, 63 Cu, 65 Cu, 64 Zn, 66 Zn, 69 Ga, 71 Ga, 75 As, 82 Se, 84 Sr, 86 Sr, 87 Sr, 88 Sr, 85 Rb, 94 Mo, 95 Mo, 97 Mo, 107 Ag, 109 Ag, 110 Cd, 111 Cd, 113 Cd, 112 Cd, 114 Cd, 116 Cd, 133 Cs, 206 Pb, 207 Pb, and 208 Pb. Content (mg/kg) of 51 V (0.012), 50 Cr (0.882), 75 As (0.017), 85 Rb (57.7), and 87 Sr (46.3) were high in Korean pork samples whereas 6 Li, 7 Li, 59 Co, 55 Mn, 58 Ni, 84 Sr, 86 Sr, 88 Sr, 111 Cd, and 133 Cs were found higher in non-Korean samples. The results of discriminant analysis showed that the trace elements content and stable isotope ratios were significant for the discrimination of geographical origins with a perfect discrimination rate of 100%. Copyright © 2018 Elsevier Ltd. All rights reserved.

Determination of Halide Concentrations at the Interface of Zwitterionic Micelles by Chemical Trapping: Influence of the Orientation of the Dipole and the Nature of the Cation.

PubMed

Cuccovia; Romsted; Chaimovich

1999-12-01

The interfacial concentrations of Cl(-) and Br(-) in aqueous zwitterionic micelles were determined by chemical trapping by analyzing product yields from spontaneous dediazoniation of micelle-bound 2,6-dimethyl-4-hexadecylbenzenediazonium ion. Interfacial concentrations of Cl(-) and Br(-) in 3-(N-hexadecyl-N, N-dimethylammonio) propane sulfonate, HPS, micelles were higher than in bulk solutions prepared with Li(+), Na(+), Rb(+), Cs(+), tetramethylammonium (TMA(+)), Mg(+2), and Ca(+2) salts. In contrast, the interfacial concentrations of Cl(-) and Br(-) were generally lower than in bulk solution in hexadecylphosphoryl choline, HDPC, micelles for all salts except Mg(+2) and Ca(+2). In both HPS and HDPC micelles the interfacial concentration of Br(-) was higher than that of Cl(-), showing that binding is anion selective. The cation had a large effect on the interfacial concentration of halide ions with HDPC micelles decreasing in the order Ca(2+) > Mg(2+) > Li(+) > Na(+) > K(+) > Cs(+) > Rb(+) > TMA(+). These results are the first direct and extensive determination of local halide ion concentration at the surface of zwitterionic micelles, and they demonstrate that chemical trapping methodology will work in membranes at physiologically relevant salt concentrations. Copyright 1999 Academic Press.

Formation of Metal-Adducted Analyte Ions by Flame-Induced Atmospheric Pressure Chemical Ionization Mass Spectrometry.

PubMed

Cheng, Sy-Chyi; Wang, Chin-Hsiung; Shiea, Jentaie

2016-05-17

A flame-induced atmospheric pressure chemical ionization (FAPCI) source, consisting of a miniflame, nebulizer, and heated tube, was developed to ionize analytes. The ionization was performed by reacting analytes with a charged species generated in a flame. A stainless steel needle deposited with saturated alkali chloride solution was introduced into the mini oxyacetylene flame to generate alkali ions, which were reacted with analytes (M) generated in a heated nebulizer. The alkali-adducted 18-crown-6 ether ions, including (M + Li)(+), (M + Na)(+), (M + K)(+), (M + Rb)(+), and (M + Cs)(+), were successfully detected on the FAPCI mass spectra when the corresponding alkali chloride solutions were separately introduced to the flame. When an alkali chloride mixture was introduced, all alkali-adducted analyte ions were simultaneously detected. Their intensity order was as follows: (M + Cs)(+) > (M + Rb)(+) > (M + K)(+) > (M + Na)(+) > (M + Li)(+), and this trend agreed with the lattice energies of alkali chlorides. Besides alkali ions, other transition metal ions such as Ni(+), Cu(+), and Ag(+) were generated in a flame for analyte ionization. Other than metal ions, the reactive species generated in the fossil fuel flame could also be used to ionize analytes, which formed protonated analyte ions (M + H)(+) in positive ion mode and deprotonated analyte ions (M - H)(-) in negative ion mode.

Syntheses and characterization of phosphonates and diphosphonates of molybdenum, A4[(MoO3)5(O3PR)2]·xH2O, A2[Mo2O5(O3PR)2] and A2[Mo2O5(O3P-R-PO3)] (A = K, Rb, Cs, Tl, NH4).

PubMed

Elias Jesu Packiam, D; Vidyasagar, Kanamaluru

2017-11-28

Twenty new molybdenum phosphonates and diphosphonates have been synthesized and structurally characterized by single crystal and powder X-ray diffraction, CHN analyses, spectroscopic and thermal studies. Four of them are molecular phenyl- and benzyl-phosphonates containing discrete [(MoO 3 ) 5 (O 3 PR) 2 ] 4- (R = Ph or CH 2 Ph) cyclic anions. The sixteen non-molecular compounds are layered isostructural phenylphosphonates, A 2 [Mo 2 O 5 (O 3 PPh) 2 ] (A = NH 4 , Tl, Rb, Cs) and K 1.5 (H 3 O) 0.5 [Mo 2 O 5 (O 3 PPh) 2 ] and the corresponding diphosphonate compounds with pillared anionic layers, A 2 [Mo 2 O 5 (O 3 P(CH 2 ) 3 PO 3 )], A 2 [Mo 2 O 5 (O 3 P(CH 2 ) 4 PO 3 )] and A 2 [Mo 2 O 5 (O 3 P(C 6 H 4 )PO 3 )]. The A + ions reside in the interlayer region as well as in the cavities within the anionic layers.

Rietveld refinement of the crystal structures of Rb2 XSi5O12 (X = Ni, Mn).

PubMed

Bell, Anthony M T; Henderson, C Michael B

2016-02-01

The synthetic leucite silicate framework mineral analogues Rb2 XSi5O12 {X = Ni [dirubidium nickel(II) penta-silicate] and Mn [dirubidium manganese(II) penta-silicate]} have been prepared by high-temperature solid-state synthesis. The results of Rietveld refinements, using X-ray powder diffraction data collected using Cu Kα X-rays, show that the title compounds crystallize in the space group Pbca and adopt the cation-ordered structure of Cs2CdSi5O12 and other leucites. The structures consist of tetra-hedral SiO4 and XO4 units sharing corners to form a partially substituted silicate framework. Extraframework Rb(+) cations sit in channels in the framework. All atoms occupy the 8c general position for this space group. In these refined structures, silicon and X atoms are ordered onto separate tetra-hedrally coordinated sites (T-sites). However, the Ni displacement parameter and the Ni-O bond lengths suggest that for the X = Ni sample, there may actually be some T-site cation disorder.

Rietveld refinement of the crystal structures of Rb2 XSi5O12 (X = Ni, Mn)

PubMed Central

Bell, Anthony M. T.; Henderson, C. Michael B.

2016-01-01

The synthetic leucite silicate framework mineral analogues Rb2 XSi5O12 {X = Ni [dirubidium nickel(II) penta­silicate] and Mn [dirubidium manganese(II) penta­silicate]} have been prepared by high-temperature solid-state synthesis. The results of Rietveld refinements, using X-ray powder diffraction data collected using Cu Kα X-rays, show that the title compounds crystallize in the space group Pbca and adopt the cation-ordered structure of Cs2CdSi5O12 and other leucites. The structures consist of tetra­hedral SiO4 and XO4 units sharing corners to form a partially substituted silicate framework. Extraframework Rb+ cations sit in channels in the framework. All atoms occupy the 8c general position for this space group. In these refined structures, silicon and X atoms are ordered onto separate tetra­hedrally coordinated sites (T-sites). However, the Ni displacement parameter and the Ni—O bond lengths suggest that for the X = Ni sample, there may actually be some T-site cation disorder. PMID:26958399

Divalent Metal-Ion Complexes with Dipeptide Ligands Having Phe and His Side-Chain Anchors: Effects of Sequence, Metal Ion, and Anchor.

PubMed

Dunbar, Robert C; Berden, Giel; Martens, Jonathan K; Oomens, Jos

2015-09-24

Conformational preferences have been surveyed for divalent metal cation complexes with the dipeptide ligands AlaPhe, PheAla, GlyHis, and HisGly. Density functional theory results for a full set of complexes are presented, and previous experimental infrared spectra, supplemented by a number of newly recorded spectra obtained with infrared multiple photon dissociation spectroscopy, provide experimental verification of the preferred conformations in most cases. The overall structural features of these complexes are shown, and attention is given to comparisons involving peptide sequence, nature of the metal ion, and nature of the side-chain anchor. A regular progression is observed as a function of binding strength, whereby the weakly binding metal ions (Ba(2+) to Ca(2+)) transition from carboxylate zwitterion (ZW) binding to charge-solvated (CS) binding, while the stronger binding metal ions (Ca(2+) to Mg(2+) to Ni(2+)) transition from CS binding to metal-ion-backbone binding (Iminol) by direct metal-nitrogen bonds to the deprotonated amide nitrogens. Two new sequence-dependent reversals are found between ZW and CS binding modes, such that Ba(2+) and Ca(2+) prefer ZW binding in the GlyHis case but prefer CS binding in the HisGly case. The overall binding strength for a given metal ion is not strongly dependent on the sequence, but the histidine peptides are significantly more strongly bound (by 50-100 kJ mol(-1)) than the phenylalanine peptides.

Mineralogical and geochemical characterization of weathering profiles developed on mylonites in the Fodjomekwet-Fotouni section of the Cameroon Shear Zone (CSZ), West Cameroon

NASA Astrophysics Data System (ADS)

Tematio, P.; Tchaptchet, W. T.; Nguetnkam, J. P.; Mbog, M. B.; Yongue Fouateu, R.

2017-07-01

The mineralogical and geochemical investigation of mylonitic weathering profiles in Fodjomekwet-Fotouni was done to better trace the occurrence of minerals and chemical elements in this area. Four representative soil profiles were identified in two geomorphological units (upland and lowland) differentiating three weathering products (organo-mineral, mineral and weathered materials). Weathering of these mylonites led to some minerals association such as vermiculite, kaolinite, goethite, smectite, halloysite, phlogopite and gibbsite. The minerals in a decreasing order of abundance are: quartz (24.2%-54.8%); kaolinite (8.4%-36.0%); phlogopite (5.5%-21.9%); goethite (7.8%-16.1%); vermiculite (6.7%-15.7%); smectite (10.2%-11.9%); gibbsite (9.0%-11.8%) and halloysite (5.6%-11.5%) respectively. Patterns of chemical elements allow highlighting three behaviors (enriched elements, depleted elements and elements with complex behavior), depending on the landscape position of the profiles. In the upland weathering products, K, Cr and REEs are enriched; Ca, Mg, Na, Mn, Rb, S and Sr are depleted while Si, Al, Fe, Ti, Ba, Co, Cu, Ga, Mo, Nb, Ni, Pb, Sc, V, Y, Zn and Zr portray a complex behavior. Contrarily, the lowland weathering profiles enriched elements are Fe, Ti, Co, Cr, Cu, V, Zr, Pr, Sm, Tb, Dy, Er and Yb; while depleted elements are Ca, Mg, K, Na, Mn, Ba, Ga, S, Sr, Y, Zn, La, Ce and Nd; and Si, Al, Mo, Nb, Ni, Pb, Rb, Sc evidenced complex behaviors. In all the studied weathering products, the REEs fractionation was also noticeable with a landscape-position dependency, showing light REEs (LREEs) enrichment in the upland areas and heavy REEs (HREEs) in lowland areas. SiO2, Al2O3 and Fe2O3 are positively correlated with most of the traces and REEs (Co, Cu, Nb, Ni, Mo, Pb, Sc, V, Zn, Zr, La, Ce, Sm, Tb, Dy, Er, Yb), pointing to the fact that they may be incorporated into newly formed clay minerals and oxides. Ba, Cr, Ga, Rb, S, Sr, Y, Pr and Nd behave like alkalis and alkaline earths, and are thus highly mobile during weathering.

The role of neutron star mergers in the chemical evolution of the Galactic halo

NASA Astrophysics Data System (ADS)

Cescutti, G.; Romano, D.; Matteucci, F.; Chiappini, C.; Hirschi, R.

2015-05-01

Context. The dominant astrophysical production site of the r-process elements has not yet been unambiguously identified. The suggested main r-process sites are core-collapse supernovae and merging neutron stars. Aims: We explore the problem of the production site of Eu. We also use the information present in the observed spread in the Eu abundances in the early Galaxy, and not only its average trend. Moreover, we extend our investigations to other heavy elements (Ba, Sr, Rb, Zr) to provide additional constraints on our results. Methods: We adopt a stochastic chemical evolution model that takes inhomogeneous mixing into account. The adopted yields of Eu from merging neutron stars and from core-collapse supernovae are those that are able to explain the average [Eu/Fe]-[Fe/H] trend observed for solar neighbourhood stars, the solar abundance of Eu, and the present-day abundance gradient of Eu along the Galactic disc in the framework of a well-tested homogeneous model for the chemical evolution of the Milky Way. Rb, Sr, Zr, and Ba are produced by both the s- and r-processes. The r-process yields were obtained by scaling the Eu yields described above according to the abundance ratios observed in r-process rich stars. The s-process contribution by spinstars is the same as in our previous papers. Results: Neutron star binaries that merge in less than 10 Myr or neutron star mergers combined with a source of r-process generated by massive stars can explain the spread of [Eu/Fe] in the Galactic halo. The combination of r-process production by neutron star mergers and s-process production by spinstars is able to reproduce the available observational data for Sr, Zr, and Ba. We also show the first predictions for Rb in the Galactic halo. Conclusions: We confirm previous results that either neutron star mergers on a very short timescale or both neutron star mergers and at least a fraction of Type II supernovae have contributed to the synthesis of Eu in the Galaxy. The r-process production of Sr, Zr, and Ba by neutron star mergers - complemented by an s-process production by spinstars - provide results that are compatible with our previous findings based on other r-process sites. We critically discuss the weak and strong points of both neutron star merging and supernova scenarios for producing Eu and eventually suggest that the best solution is probably a mixed one in which both sources produce Eu. In fact, this scenario reproduces the scatter observed in all the studied elements better. Warning, no authors found for 2015A&A...577A.131.

Sources of land-derived runoff to a coral reef-fringed embayment identified using geochemical tracers in nearshore sediment traps

USGS Publications Warehouse

Takesue, Renee K.; Bothner, Michael H.; Reynolds, Richard L.

2009-01-01

Geochemical tracers, including Ba, Co, Th, 7Be, 137Cs and 210Pb, and magnetic properties were used to characterize terrestrial runoff collected in nearshore time-series sediment traps in Hanalei Bay, Kauai, during flood and dry conditions in summer 2006, and to fingerprint possible runoff sources in the lower watershed. In combination, the tracers indicate that runoff during a flood in August could have come from cultivated taro fields bordering the lower reach of the river. Land-based runoff associated with summer floods may have a greater impact on coral reef communities in Hanalei Bay than in winter because sediment persists for several months. During dry periods, sediment carried by the Hanalei River appears to have been mobilized primarily by undercutting of low 7Be, low 137Cs riverbanks composed of soil weathered from tholeiitic basalt with low Ba and Co concentrations. Following a moderate rainfall event in September, high 7Be sediment carried by the Hanalei River was probably mobilized by overland flow in the upper watershed. Ba-desorption in low-salinity coastal water limited its use to a qualitative runoff tracer in nearshore sediment. 210Pb had limited usefulness as a terrestrial tracer in the nearshore due to a large dissolved oceanic source and scavenging onto resuspended bottom sediment. 210Pb-scavenging does, however, illustrate the role resuspension could play in the accumulation of particle-reactive contaminants in nearshore sediment. Co and 137Cs were not affected by desorption or geochemical scavenging and showed the greatest potential as quantitative sediment provenance indicators in material collected in nearshore sediment traps.

Compton scattering studies and electronic properties of BaTiO3

NASA Astrophysics Data System (ADS)

Meena, Seema Kumari; Bapna, Komal; Heda, N. L.; Ahuja, B. L.

2018-04-01

We present the experimental momentum density of BaTiO3 measured using 20 Ci 137Cs Compton spectrometer. The experimental Compton profile (CP) has been compared with the linear combination of atomic orbitals (LCAO) based theoretical profiles for various exchange-correlation potentials. It is found that LCAO-B3PW based CP gives a better agreement with experiment than other theoretical profiles. We have also deduced the energy bands and density of states (DOS) for BaTiO3 using LCAO-B3PW scheme. The energy bands and DOS suggest an indirect band gap in the system arising due to O-2p states of valence band and Ti-3d states of conduction band. Peculiar electronic response of this system is found to be mainly due to hybridized states of Ba-5p/5s and O-2p orbitals.

Chemical data and statistical interpretations for rocks and ores from the Ranger uranium mine, Northern Territory, Australia

USGS Publications Warehouse

Nash, J. Thomas; Frishman, David

1983-01-01

Analytical results for 61 elements in 370 samples from the Ranger Mine area are reported. Most of the rocks come from drill core in the Ranger No. 1 and Ranger No. 3 deposits, but 20 samples are from unmineralized drill core more than 1 km from ore. Statistical tests show that the elements Mg, Fe, F, Be, Co, Li, Ni, Pb, Sc, Th, Ti, V, CI, As, Br, Au, Ce, Dy, La Sc, Eu, Tb, Yb, and Tb have positive association with uranium, and Si, Ca, Na, K, Sr, Ba, Ce, and Cs have negative association. For most lithologic subsets Mg, Fe, Li, Cr, Ni, Pb, V, Y, Sm, Sc, Eu, and Yb are significantly enriched in ore-bearing rocks, whereas Ca, Na, K, Sr, Ba, Mn, Ce, and Cs are significantly depleted. These results are consistent with petrographic observations on altered rocks. Lithogeochemistry can aid exploration, but for these rocks requires methods that are expensive and not amenable to routine use.

Process for the production of .sup.18 F-2-deoxy-2-fluoro-D-glucose

DOEpatents

Elmaleh, David R.; Levy, Shlomo; Shiue, Chyng-Yann; Wolf, Alfred P.

1986-01-01

Process for the production of 2-deoxy-2-fluoro-D-glucose and the corresponding .sup.18 F-compound in which methyl 4,6-O-benzylidine-3-O-methyl-2-O-trifluoromethanesulfonyl-.beta.-D-mannopy ranoside is reacted with a triflating reagent, the resulting compound reacted with CsHF.sub.2, RbF or the corresponding .sup.18 F-compounds, and thereafter the alkyl groups removed by hydrolysis.

Alloying n-Butylamine into CsPbBr3 to Give a Two-Dimensional Bilayered Perovskite Ferroelectric Material.

PubMed

Wu, Zhenyue; Ji, Chengmin; Li, Lina; Kong, Jintao; Sun, Zhihua; Zhao, Sangen; Wang, Sasa; Hong, Maochun; Luo, Junhua

2018-05-11

Cesium-lead halide perovskites (e.g. CsPbBr 3 ) have gained attention because of their rich physical properties, but their bulk ferroelectricity remains unexplored. Herein, by alloying flexible organic cations into the cubic CsPbBr 3 , we design the first cesium-based two-dimensional (2D) perovskite ferroelectric material with both inorganic alkali metal and organic cations, (C 4 H 9 NH 3 ) 2 CsPb 2 Br 7 (1). Strikingly, 1 shows a high Curie temperature (T c =412 K) above that of BaTiO 3 (ca. 393 K) and notable spontaneous polarization (ca. 4.2 μC cm -2 ), triggered by not only the ordering of organic cations but also atomic displacement of inorganic Cs + ions. To our knowledge, such a 2D bilayered Cs + -based metal-halide perovskite ferroelectric material with inorganic and organic cations is unprecedented. 1 also shows photoelectric semiconducting behavior with large "on/off" ratios of photoconductivity (>10 3 ). © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Development and evaluation of geochemical methods for the sourcing of archaeological maize

USGS Publications Warehouse

Benson, L.V.; Taylor, Howard E.; Peterson, K.A.; Shattuck, B.D.; Ramotnik, C.A.; Stein, J.R.

2008-01-01

Strontium (Sr)-isotope values on bone from deer mice pairs from 12 field sites in the Chaco Canyon area, New Mexico, were compared with isotope values of synthetic soil waters from the same fields. The data indicate that mice obtain Sr from near-surface sources and that soil samples collected at depths ranging from 25 to 95 cm contain Sr that is more accessible to the deep roots of maize; thus, synthetic soil solutions provide better data for the sourcing of archaeological maize. However, the Sr-isotope composition of mice may be more valuable in sourcing archaeological remains of animals such as rabbit, turkey, and deer. In a separate study, five Native American maize (Zea mays L. ssp. mays) accessions grown out at New Mexico State University Agricultural Science Center, Farmington, New Mexico were used to determine if soil-water metal pairs partition systematically into cobs and kernels. The sampled maize included landraces from three Native American groups (Acoma, Hopi, Zuni) that still occupy the Four Corners area. Two cobs each were picked from 10 plants of each landrace. Partitioning of the Ba/Mn, Ba/Sr, Ca/Sr, and K/Rb metal pairs from the soil water to the cob appears to behave in a systematic fashion. In addition, 51 rare earth element (REE) pairs also appear to systematically partition from the soil water into cobs; however, the ratios of the REE dissolved in the soil waters are relatively invariant; therefore, the distribution coefficients that describe the partitioning of REE from the soil water to the cob may not apply to archeological cobs grown under chemically heterogeneous conditions. Partitioning of Ba/Rb, Ba/Sr, Mg/P, and Mn/P metal pairs from the soil water to kernels also behaves in a systematic fashion. Given that modern Native American landraces were grown under optimal environmental conditions that may not have been duplicated by prehistoric Native Americans, the distribution coefficients obtained in this study should be used with caution. ?? 2007 Elsevier Ltd. All rights reserved.

Fluid inclusion, geochemical, Rb-Sr and Sm-Nd isotope studies on tungsten mineralized Degana and Balda granites of the Aravalli craton, NW India

NASA Astrophysics Data System (ADS)

Vijay Anand, Sundarrajan; Pandian, M. S.; Balakrishnan, S.; Sivasubramaniam, R.

2018-06-01

Granitic plutons occurring within and to the west of the Delhi Fold Belt in the Aravalli craton, northwestern India are the result of widespread felsic magmatism during Neoproterozoic, some of which are associated with greisen and skarn tungsten deposits. In this paper, we present the result of our study on fluid inclusions, geochemistry and geochronology of two such tungsten mineralized granite plutons at Degana and Balda, and interpret the nature of ore fluid, and petrogenesis and age of these mineralized granites. Fluid inclusion study reveals coexistence of moderate and hyper-saline aqueous fluid inclusions along with aqueous-carbonic inclusions, suggesting their origin due to liquid immiscibility during fluid-rock interaction. Geochemically, the granites are peraluminous, Rb enriched, Sr and Ba depleted and highly differentiated. The Rb-Sr isotopic systematics yielded 795± 11 Ma for Balda granite and 827± 8 Ma for Degana granite. We show that major phase of widespread granitoid magmatism and mineralization during the Neoproterozoic (840-790 Ma) in NW India is coeval with breakup of the Rodinia supercontinent and infer a causal relationship between them.

Assessment of atmospheric deposition of heavy metals and other elements in Belgrade using the moss biomonitoring technique and neutron activation analysis.

PubMed

Anicić, Mira; Frontasyeva, Marina V; Tomasević, Milica; Popović, Aleksandar

2007-06-01

This study aimed at assessing atmospheric deposition of heavy metals and other elements using the moss genera Brachythecium sp. (B. rutabulum and B. salebrosum) and Eurhynchium sp. (E. hians and E. striatum) collected in autumn 2004 in the urban area of Belgrade. The concentrations of 36 elements (Na, Mg, Al, Cl, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Zn, As, Se, Br, Rb, Sr, Mo, Sb, I, Cs, Ba, La, Ce, Sm, Tb, Dy, Hf, Ta, W, Hg, Th, U) were determined in moss and local topsoil samples by instrumental neutron activation analysis. The concentration of elements in moss positively correlated to those obtained for topsoil. High enrichment factors for As, Zn, Mo, Br, Sb, Se, Hg and Cl, calculated to continental crust composition, gave an evidence for anthropogenic impact on urban area, mainly due to intensive vehicular traffic and fossil fuel combustion. The concentration of elements in moss, characteristic for fossil fuel combustion, obtained in this study were substantially lower than in the previous investigation (2000) conducted in the area of Belgrade. The level of concentrations for V, Cr, Ni, and As in moss from this study correlated to those measured for neighboring countries, and were several times higher than the base-level data from low polluted areas. The level of accumulated elements in both investigated moss genera were similar and all studied species could be combined for biomonitoring purposes in urban areas.

A provenance study of iron archaeological artefacts by Inductively Coupled Plasma-Mass Spectrometry multi-elemental analysis

NASA Astrophysics Data System (ADS)

Desaulty, Anne-Marie; Mariet, Clarisse; Dillmann, Philippe; Joron, Jean Louis; Fluzin, Philippe

2008-11-01

Raw materials and wastes (i.e. ore, slag and laitier) from ironmaking archaeological sites have been analyzed in order to understand the behavior of the trace elements in the ancient ironmaking processes and to find the significant-most elements to characterize an iron making region. The ICP-MS (Inductively Coupled Plasma Mass Spectrometry) appears to be an excellent technique for this type of studies. The comparison between the ICP-MS results obtained with the Standard Addition method and the INAA (Instrumental Neutron Activation Analyses) results proved that Sc, Co, (Ni), Rb, Cs, Ba, La, Ce, Sm, Eu, Yb, Hf, Th, U contents in the ores, slag and laitiers, and Co and Ni contents in the cast iron can be successfully determined by ICP-MS after wet acid digestion (low detection limits, good sensitivity and precision). By using significant trace element pairs (Yb/Ce, Ce/Th, La/Sc, U/Th, Nb/Y) present in the ores, laitiers and slag, it is possible to discriminate different French ironmaking regions as the Pays de Bray, Lorraine and Pays d'Ouche. These results open the way to further studies on the provenance of iron objects. The comparison between the ICP-MS results obtained with the Standard Calibration Curves method and the INAA results shows that matrices rich in iron, affect the ICP-MS analyses by suppressing the analytes signal. Further studies are necessary to improve understanding matrix effects.

Microwave-assisted Extraction of Rare Earth Elements from Petroleum Refining Catalysts and Ambient Fine Aerosols Prior to Inductively Coupled Plasma - Mass Spectrometry

NASA Technical Reports Server (NTRS)

Mittlefehldt, David W.; Kulkarni, Pranav; Chellam, Shankar

2006-01-01

In the absence of a certified reference material, a robust microwave-assisted acid digestion procedure followed by inductively coupled plasma - mass spectrometry (ICP-MS) was developed to quantify rare earth elements (REEs) in fluidized-bed catalytic cracking (FCC) catalysts and atmospheric fine particulate matter (PM2.5). High temperature (200 C), high pressure (200 psig), acid digestion (HNO3, HF, and H3BO3) with 20 minute dwell time effectively solubilized REEs from six fresh catalysts, a spent catalyst, and PM2.5. This method was also employed to measure 27 non-REEs including Na, Mg, Al, Si, K, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, As, Se, Rb, Sr, Zr, Mo, Cd, Cs, Ba, Pb, and U. Complete extraction of several REEs (Y, La, Ce, Pr, Nd, Tb, Dy, and Er) required HF indicating that they were closely associated with the aluminosilicate structure of the zeolite FCC catalysts. Internal standardization using 115In quantitatively corrected non-spectral interferences in the catalyst digestate matrix. Inter-laboratory comparison using ICP-optical emission spectroscopy (ICP-OES) and instrumental neutron activation analysis (INAA) demonstrated the applicability of the newly developed analytical method for accurate analysis of REEs in FCC catalysts. The method developed for FCC catalysts was also successfully implemented to measure trace to ultra-trace concentrations of La, Ce, Pr, Nd, Sm, Gd, Eu, and Dy in ambient PM2.5 in an industrial area of Houston, TX.

Lack of transgene and glyphosate effects on yield, and mineral and amino acid content of glyphosate-resistant soybean.

PubMed

Duke, Stephen O; Rimando, Agnes M; Reddy, Krishna N; Cizdziel, James V; Bellaloui, Nacer; Shaw, David R; Williams, Martin M; Maul, Jude E

2018-05-01

There has been controversy as to whether the glyphosate resistance gene and/or glyphosate applied to glyphosate-resistant (GR) soybean affect the content of cationic minerals (especially Mg, Mn and Fe), yield and amino acid content of GR soybean. A two-year field study (2013 and 2014) examined these questions at sites in Mississippi, USA. There were no effects of glyphosate, the GR transgene or field crop history (for a field with both no history of glyphosate use versus one with a long history of glyphosate use) on grain yield. Furthermore, these factors had no consistent effects on measured mineral (Al, As, Ba, Cd, Ca, Co, Cr, Cs, Cu, Fe, Ga, K, Li, Mg, Mn, Ni, Pb, Rb, Se, Sr, Tl, U, V, Zn) content of leaves or harvested seed. Effects on minerals were small and inconsistent between years, treatments and mineral, and appeared to be random false positives. No notable effects on free or protein amino acids of the seed were measured, although glyphosate and its degradation product, aminomethylphosphonic acid (AMPA), were found in the seed in concentrations consistent with previous studies. Neither glyphosate nor the GR transgene affect the content of the minerals measured in leaves and seed, harvested seed amino acid composition, or yield of GR soybean. Furthermore, soils with a legacy of GR crops have no effects on these parameters in soybean. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Hydration of cations: a key to understanding of specific cation effects on aggregation behaviors of PEO-PPO-PEO triblock copolymers.

PubMed

Lutter, Jacob C; Wu, Tsung-yu; Zhang, Yanjie

2013-09-05

This work reports results from the interactions of a series of monovalent and divalent cations with a triblock copolymer, poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) (PEO-PPO-PEO). Phase transition temperatures of the polymer in the presence of chloride salts with six monovalent and eight divalent cations were measured using an automated melting point apparatus. The polymer undergoes a two-step phase transition, consisting of micellization of the polymer followed by aggregation of the micelles, in the presence of all the salts studied herein. The results suggest that hydration of cations plays a key role in determining the interactions between the cations and the polymer. The modulation of the phase transition temperature of the polymer by cations can be explained as a balance between three interactions: direct binding of cations to the oxygen in the polymer chains, cations sharing one water molecule with the polymer in their hydration layer, and cations interacting with the polymer via two water molecules. Monovalent cations Na(+), K(+), Rb(+), and Cs(+) do not bind to the polymer, while Li(+) and NH4(+) and all the divalent cations investigated including Mg(2+), Ca(2+), Sr(2+), Ba(2+), Co(2+), Ni(2+), Cu(2+), and Cd(2+) bind to the polymer. The effects of the cations correlate well with their hydration thermodynamic properties. Mechanisms for cation-polymer interactions are discussed.

Estimation of discrimination errors in the technique for determining the geographic origin of onions by mineral composition: interlaboratory study.

PubMed

Ariyama, Kaoru; Kadokura, Masashi; Suzuki, Tadanao

2008-01-01

Techniques to determine the geographic origin of foods have been developed for various agricultural and fishery products, and they have used various principles. Some of these techniques are already in use for checking the authenticity of the labeling. Many are based on multielement analysis and chemometrics. We have developed such a technique to determine the geographic origin of onions (Allium cepa L.). This technique, which determines whether an onion is from outside Japan, is designed for onions labeled as having a geographic origin of Hokkaido, Hyogo, or Saga, the main onion production areas in Japan. However, estimations of discrimination errors for this technique have not been fully conducted; they have been limited to those for discrimination models and do not include analytical errors. Interlaboratory studies were conducted to estimate the analytical errors of the technique. Four collaborators each determined 11 elements (Na, Mg, P, Mn, Zn, Rb, Sr, Mo, Cd, Cs, and Ba) in 4 test materials of fresh and dried onions. Discrimination errors in this technique were estimated by summing (1) individual differences within lots, (2) variations between lots from the same production area, and (3) analytical errors. The discrimination errors for onions from Hokkaido, Hyogo, and Saga were estimated to be 2.3, 9.5, and 8.0%, respectively. Those for onions from abroad in determinations targeting Hokkaido, Hyogo, and Saga were estimated to be 28.2, 21.6, and 21.9%, respectively.

Spectrophotometric and electrochemical study for metal ion binding of azocalix[4]arene bearing p-ethylester group

NASA Astrophysics Data System (ADS)

Kim, Tae Hyun

2017-05-01

The complexation behavior of diazophenylcalix[4]arene bearing para-ethylester group (p-EAC) for alkali, alkaline earth, various heavy and transition metal ions (Li+, Na+, K+, Rb+, Cs+, Mg2 +, Ca2 +, Sr2 +, Ba2 +, Cr3 +, Fe2 +, Co2 +, Ni2 +, Cu2 +, Zn2 +, Pb2 +) was investigated by spectrophotometric and electrochemical methods in CH3CN. p-EAC exhibits decreased absorbance at 353 nm in the presence of Cr3 +, Fe2 +, Pb2 +, and Cu2 +. The spectra of p-EAC showed bathochromic shift in absorption maximum on the addition of Cr3 +, Fe2 +, or Pb2 + with decreasing order of absorbance (Cr3 + > Fe2 + > Pb2 +), and on the other hand, hypsochromic shift on the addition of Cu2 +. This leads to the selective coloration from light green to orange and colorless for Cr3 + and Cu2 + that can be detected by the naked eye, respectively. In electrochemistry experiments, p-EAC also showed two different types of voltammetric changes toward Cr3 +, Fe2 +, or Pb2 +, and toward Cu2 +, whereas no significant changes occurred in the presence of the other metal ions. Nonlinear fitting curve procedure was used to determine a logarithmic value of 5.20, 4.92, 3.54 and 4.80 for the stability constants of the complex of p-EAC with Cr3 +, Fe2 +, Pb2 +, and Cu2 +, respectively.

Selective oxidation of alkanes and/or alkenes to valuable oxygenates

DOEpatents

Lin, Manhua; Pillai, Krishnan S.

2011-02-15

A catalyst, its method of preparation and its use for producing at least one of methacrolein and methacrylic acid, for example, by subjecting isobutane or isobutylene or a mixture thereof to a vapor phase catalytic oxidation in the presence of air or oxygen. In the case where isobutane alone is subjected to a vapor phase catalytic oxidation in the presence of air or oxygen, the product is at least one of isobutylene, methacrolein and methacrylic acid. The catalyst comprises a compound having the formula A.sub.aB.sub.bX.sub.xY.sub.yZ.sub.zO.sub.o wherein A is one or more elements selected from the group of Mo, W and Zr, B is one or more elements selected from the group of Bi, Sb, Se, and Te, X is one or more elements selected from the group of Al, Bi, Ca, Ce, Co, Fe, Ga, Mg, Ni, Nb, Sn, W and Zn, Y is one or more elements selected from the group of Ag, Au, B, Cr, Cs, Cu, K, La, Li, Mg, Mn, Na, Nb, Ni, P, Pb, Rb, Re, Ru, Sn, Te, Ti, V and Zr, and Z is one or more element from the X or Y groups or from the following: As, Ba, Pd, Pt, Sr, or mixtures thereof, and wherein a=1, 0.05

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

Baljinnyam, N.; Frontasyeva, M. V.; Ostrovnaya, T. M.

Asian medicinal herbs Chrysanthemum (Spiraea aquilegifolia Pall.) and Red Sandalwood (Pterocarpus Santalinus) are widely used in folk and Ayurvedic medicine for healing and preventing some diseases. The modern medical science has proved that the Chrysanthemum (Spiraea aquilegifolia Pall.) possesses the following functions: reducing blood press, dispelling cancer cell, coronary artery's expanding and bacteriostating and Red Sandalwood (Pterocarpus Santalinus) is recommended against headache, toothache, skin diseases, vomiting and sometimes it is taken for treatment of diabetes. Species of Chrysanthemums were collected in the north-eastern and central Mongolia, and the Red Sandalwood powder was imported from India. Samples of Chrysanthemums (branches, flowersmore » and leaves)(0.5 g) and red sandalwood powder (0.5 g) were subjected to the multi-element instrumental neutron activation analysis using epithermal neutrons (ENAA) at the IBR-2 reactor, Frank Laboratory of Neutron Physics (FLNP) JINR, Dubna. A total of 41 elements (Na, Mg, Al, Cl, K, Ca, Sc, V, Cr, Mn, Fe, Co, Ni, Zn, As, Se, Br, Rb, Sr, Zr, Mo, Cd, Cs, Ba, La, Hf, Ta, W, Sb, Au, Hg, Ce, Nd, Sm, Eu, Tb, Dy, Yb, Th, U, Lu) were determined. For the first time such a large group of elements was determined in the herbal plants used in Mongolia. The quality control of the analytical results was provided by using certified reference material Bowen Cabbage. The results obtained are compared to the ''Reference plant? data (B. Markert, 1992) and interpreted in terms of excess of such elements as Se, Cr, Ca, Fe, Ni, Mo, and rare earth elements.« less

Radiopaque Strontium Fluoroapatite Glass-Ceramics.

PubMed

Höland, Wolfram; Schweiger, Marcel; Dittmer, Marc; Ritzberger, Christian

2015-01-01

The controlled precipitation of strontium fluoroapatite crystals was studied in four base glass compositions derived from the SiO2-Al2O3-Y2O3-SrO-Na2O-K2O/Rb2O/Cs2O-P2O5-F system. The crystal phase formation of these glasses and the main properties of the glass-ceramics, such as thermal and optical properties and radiopacity were compared with a fifth, a reference glass-ceramic. The reference glass-ceramic was characterized as Ca-fluoroapatite glass-ceramic. The four strontium fluoroapatite glass-ceramics showed the following crystal phases: (a) Sr5(PO4)3F - leucite, KAlSi2O6, (b) Sr5(PO4)3F - leucite, KAlSi2O6, and nano-sized NaSrPO4, (c) Sr5(PO4)3F - pollucite, CsAlSi2O6, and nano-sized NaSrPO4, and (d) Sr5(PO4)3F - Rb-leucite, RbAlSi2O6, and nano-sized NaSrPO4. The proof of crystal phase formation was possible by X-ray diffraction. The microstructures, which were studied using scanning electron microscopy, demonstrated a uniform distribution of the crystals in the glass matrix. The Sr-fluoroapatites were precipitated based on an internal crystallization process, and the crystals demonstrated a needle-like morphology. The study of the crystal growth of needle-like Sr-fluoroapatites gave a clear evidence of an Ostwald ripening mechanism. The formation of leucite, pollucite, and Rb-leucite was based on a surface crystallization mechanism. Therefore, a twofold crystallization mechanism was successfully applied to develop these types of glass-ceramics. The main focus of this study was the controlled development of glass-ceramics exhibiting high radiopacity in comparison to the reference glass-ceramic. This goal could be achieved with all four glass-ceramics with the preferred development of the Sr-fluoroapatite - pollucite-type glass-ceramic. In addition to this main development, it was possible to control the thermal properties. Especially the Rb-leucite containing glass-ceramic showed the highest coefficient of thermal expansion (CTE). These glass-ceramics allow optical properties, especially the translucency and color, to be tailored to the needs of biomaterials for dental applications. The authors conclude that it is possible to use twofold crystallization processes to develop glass-ceramic biomaterials featuring different properties, such as specific radiopacity values, CTEs, and optical characteristics.

Radiopaque Strontium Fluoroapatite Glass-Ceramics

PubMed Central

Höland, Wolfram; Schweiger, Marcel; Dittmer, Marc; Ritzberger, Christian

2015-01-01

The controlled precipitation of strontium fluoroapatite crystals was studied in four base glass compositions derived from the SiO2–Al2O3–Y2O3–SrO–Na2O–K2O/Rb2O/Cs2O–P2O5–F system. The crystal phase formation of these glasses and the main properties of the glass-ceramics, such as thermal and optical properties and radiopacity were compared with a fifth, a reference glass-ceramic. The reference glass-ceramic was characterized as Ca-fluoroapatite glass-ceramic. The four strontium fluoroapatite glass-ceramics showed the following crystal phases: (a) Sr5(PO4)3F – leucite, KAlSi2O6, (b) Sr5(PO4)3F – leucite, KAlSi2O6, and nano-sized NaSrPO4, (c) Sr5(PO4)3F – pollucite, CsAlSi2O6, and nano-sized NaSrPO4, and (d) Sr5(PO4)3F – Rb-leucite, RbAlSi2O6, and nano-sized NaSrPO4. The proof of crystal phase formation was possible by X-ray diffraction. The microstructures, which were studied using scanning electron microscopy, demonstrated a uniform distribution of the crystals in the glass matrix. The Sr-fluoroapatites were precipitated based on an internal crystallization process, and the crystals demonstrated a needle-like morphology. The study of the crystal growth of needle-like Sr-fluoroapatites gave a clear evidence of an Ostwald ripening mechanism. The formation of leucite, pollucite, and Rb-leucite was based on a surface crystallization mechanism. Therefore, a twofold crystallization mechanism was successfully applied to develop these types of glass-ceramics. The main focus of this study was the controlled development of glass-ceramics exhibiting high radiopacity in comparison to the reference glass-ceramic. This goal could be achieved with all four glass-ceramics with the preferred development of the Sr-fluoroapatite – pollucite-type glass-ceramic. In addition to this main development, it was possible to control the thermal properties. Especially the Rb-leucite containing glass-ceramic showed the highest coefficient of thermal expansion (CTE). These glass-ceramics allow optical properties, especially the translucency and color, to be tailored to the needs of biomaterials for dental applications. The authors conclude that it is possible to use twofold crystallization processes to develop glass-ceramic biomaterials featuring different properties, such as specific radiopacity values, CTEs, and optical characteristics. PMID:26528470

Water Quality Data from Two Agricultural Drainage Basins in Northwestern Indiana and Northeastern Illinois: I. Lagrangian and Synoptic Data, 1999-2002

DTIC Science & Technology

2004-01-01

of 370 °C with sulfuric acid , potassium sulfate and mercury (II). Therefore, in this report, Kjeldahl nitrogen refers to ammonium ions plus organic... sulfuric acid to a fixed point endpoint according to the techniques of Kramer (1982) using a Gran’s titration calculation. Standard reference water...Name Al Aluminum H Hydrogen Rb Rubidium As Arsenic HCO 3 Bicarbonate Re Rhenium B Boron Hg Mercury S Sulfur Ba Barium Ho Holmium SO 4

Nonlinearity, resonance, charging, and motion at the atomic scale studied with scanning tunneling microscopes

NASA Astrophysics Data System (ADS)

Tu, Xiuwen

2008-10-01

Several novel phenomena at the single-atom and single-molecule level occurring on the surfaces of single crystals were studied with home-built low temperature scanning tunneling microscopes. The results revealed intriguing properties of single atoms and single molecules, including nonlinearity, resonance, charging, and motion. First, negative differential resistance (NDR) was observed in the dI/dV spectra for single copper-phthalocyanine (CuPc) molecules adsorbed on one- and two-layer sodium bromide (NaBr), but not for single CuPc molecules adsorbed on three-layer NaBr, all grown on a NiAl(110) surface. This transition from NDR to the absence of NDR was explained as the result of competing effects in the double-barrier tunnel junction (DBTJ) and was reproduced in a calculation based on a resonant-tunneling model. Second, the nonlinearity of the STM junction due to a single manganese (Mn) atom or MnCO molecule adsorbed on a NiAl(110) surface was used to rectify microwave irradiation. The resulting rectification current was shown to be sensitive to the spin-splitting of the electronic states of the Mn atom and to the vibrations of the MnCO molecule. Next, the ordering of cesium (Cs) atoms adsorbed on a Au(111) surface and a NiAl(110) surface was imaged in real space. Because of charge transfer to the substrates, Cs adatoms were positively charged on both surfaces. Even at 12 K, Cs adatoms were able to move and adjust according to coverage. On Au(111), the Cs first layer had a quasi-hexagonal lattice and islands of the second Cs layer did not appear until the first was completed. On NiAl(110), a locally disordered Cs first layer was observed before a locally ordered layer appeared at higher coverages. The cation-pi interactions were then studied at the single molecular level. We were able to form cation-pi complexes such as Cs···DSB, Cs···DSB···Cs, Rb···DSB, and Rb···ZnEtiol controllably by manipulation with the STM tip. We could also separate these complexes controllably by voltage pulses. STM imaging and spectroscopy revealed precise information about the atomic and electronic structure of these cation-pi complexes. Finally, electron transport through single atoms and molecules in a double-barrier tunnel junction (DBTJ) was examined. Charge bistability was observed for single ZnEtioI molecules adsorbed in several different conformations on ultrathin aluminum oxide. A sudden decrease in local apparent barrier height (LABH) was observed at the onset of an adsorbate electronic orbital for single ZnEtioI molecules and Cs atoms supported by the ultrathin aluminum oxide. The resonant-tunneling model, which was proposed to explain the transition from NDR to the absence of NDR, was found useful in explaining the sudden decrease in LABH, too. NDR, bipolar tunneling, and vibronic states were also observed and discussed in the context of DBTJ.

The ionic selectivity and calcium dependence of the light-sensitive pathway in toad rods.

PubMed Central

Hodgkin, A L; McNaughton, P A; Nunn, B J

1985-01-01

A new method is described for determining the effects of rapid changes in ionic concentration on the light-sensitive currents of rod outer segments. Replacing Na with another monovalent cation caused a rapid change in current followed by an exponential decline of time constant 0.5-2 s. From the magnitude of the initial rapid change in current we conclude that Li, Na, and K and Rb ions pass readily through the light-sensitive channel in the presence of 1 mM-Ca, whereas Cs crosses with difficulty and choline, tetramethylammonium and tetraethylammonium not at all. The effect of reducing Ca in the external medium indicates that the residual inward current recorded for a few seconds when Na is replaced by an impermeant ion is carried largely by Ca ions. With 1 microM-Ca in the external medium the relative ability of monovalent cations to carry light-sensitive current is Li:Na:K:Rb:Cs = 1.4:1:0.8:0.6:0.15. The same order applied in the physiological region but the values are less certain. Large transient inward currents are seen if external Ca is raised form 1 microM to 5 mM or more; these currents which are maximal in an isotonic Ca solution are presumably carried by Ca. The effect of monovalent cations on the number of open light-sensitive channels was tested by adding the cation to a solution containing 55 mM-Na. Na ions open light-sensitive channels with a delay, probably by promoting Na-Ca exchange; K and Rb close channels by inhibiting exchange; Li and Cs seem inert in the exchange mechanism. The rate at which inward current declines in low [Na]o or high [Ca]o is accelerated by weak background lights and slowed by 3-isobutyl-1-methylxanthine (IBMX), which inhibits the hydrolysis of cGMP. On returning to Ringer solution after a period in low [Na]o the current recovers with a delay of about 1 s which decreases as the Ca concentration of the low [Na]o medium is reduced. We conclude that intracellular Ca has a strong effect on the number of open light-sensitive channels. None the less, several observations are inconsistent with channel closure being dependent simply on combination with internal Ca. PMID:2580087

Nonparametric Trajectory Analysis of CMAPS Data

EPA Science Inventory

As part of the Cleveland Multiple Air Pollutant Study (CMAPS), 30-minute average concentrations of the elemental composition of PM2.5 were made at two sites during the months of August 2009 and February 2010. The elements measured were: Al, As, Ba, Be, Ca, Cd, Ce, Co, Cr, Cs, Cu...

Characterisation of CS Aerosol used in Mask Test Facilities

DTIC Science & Technology

2010-04-01

ultrafine particles ? Inhalation Toxicology, 1995. 7: p. 111–124. 15. Peters, A., et al., Respiratory effects are associated with the number of... ultrafine particles . American Journal of Respiratory and Critical Care Medicine, 1997. 155: p. 1376–1383. 16. Jamriska, M., L. Morawska, and B.A. Clark

Alkali metal intercalates of molybdenum disulfide.

NASA Technical Reports Server (NTRS)

Somoano, R. B.; Hadek, V.; Rembaum, A.

1973-01-01

Study of some of the physicochemical properties of compounds obtained by subjecting natural molybdenite and single crystals of molybdenum disulfide grown by chemical vapor transport to intercalation with the alkali group of metals (Li, Na, K, Rb, and Cs) by means of the liquid ammonia technique. Reported data and results include: (1) the intercalation of the entire alkali metal group, (2) stoichiometries and X-ray data on all of the compounds, and (3) superconductivity data for all the intercalation compounds.

Physics and chemistry of MoS2 intercalation compounds

NASA Technical Reports Server (NTRS)

Woollam, J. A.; Somoano, R. B.

1977-01-01

An investigation is made of the physics and chemistry of MoS2 intercalation compounds. These compounds may be separated into two groups according to their stoichiometry, structure and superconducting properties. The first group consists of Na, Ca, and Sr intercalates, and the second group consists of K, Rb, and Cs intercalates. Particular attention is given to the structure of the electronic energy band and to the normal state and superconducting properties of these compounds.

Emergent odd-parity multipoles and magnetoelectric effects on a diamond structure: Implication for the 5 d transition metal oxides A OsO4 (A =K ,Rb, and Cs)

NASA Astrophysics Data System (ADS)

Hayami, Satoru; Kusunose, Hiroaki; Motome, Yukitoshi

2018-01-01

We report our theoretical predictions on the linear magnetoelectric (ME) effects originating from odd-parity multipoles associated with spontaneous spin and orbital ordering on a diamond structure. We derive a two-orbital model for d electrons in eg orbitals by including the effective spin-orbit coupling which arises from the mixing between eg and t2 g orbitals. We show that the model acquires a net antisymmetric spin-orbit coupling once staggered spin and orbital orders occur spontaneously. The staggered orders are accompanied by odd-parity multipoles: magnetic monopole, quadrupoles, and toroidal dipoles. We classify the types of the odd-parity multipoles according to the symmetry of the spin and orbital orders. Furthermore, by computing the ME tensor using the linear response theory, we show that the staggered orders induce a variety of the linear ME responses. We elaborate all possible ME responses for each staggered order, which are useful to identify the order parameter and to detect the odd-parity multipoles by measuring the ME effects. We also elucidate the effect of lowering symmetry by a tetragonal distortion, which leads to richer ME responses. The implications of our results are discussed for the 5 d transition metal oxides, A OsO4 (A =K,Rb, and Cs) , in which the order parameters are not fully identified.

Compositions of supersaturated solutions for enhanced growth of {alpha}-NiSO{sub 4} . 6H{sub 2}O, Me{sub 2}Ni(SO{sub 4}){sub 2} . 6H{sub 2}O, MeH{sub 2}PO{sub 4} [Me = Li, Na, K, Rb, Cs, NH{sub 4}], and K(H{sub x}D{sub 1-x}){sub 2}PO{sub 4} single crystals

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

Soboleva, L. V., E-mail: afkonst@ns.crys.ras.ru

2008-05-15

The possibility of determining the optimal compositions and temperatures of supersaturated solutions for enhanced growth of single crystals of congruently and incongruently dissolving solid phases from the solubility diagrams of ternary systems is shown, and this approach is justified. The NiSO{sub 4}-H{sub 2}SO{sub 4}-H{sub 2}O, Me{sub 2}SO{sub 4}-NiSO{sub 4}-H{sub 2}O, and Me{sub 2}O-P{sub 2}O{sub 5}-H{sub 2}O(D{sub 2}O) systems have been used to determine the optimal compositions and temperatures of supersaturated solutions for growth of {alpha}-NiSO{sub 4} . 6H{sub 2}O, Me{sub 2}Ni(SO{sub 4}){sub 2} . 6H{sub 2}O, MeH{sub 2}PO{sub 4} [Me = Li, Na, K, Rb, Cs, NH{sub 4}], and Kmore » (H{sub x} D{sub 1-x}){sub 2}PO{sub 4} (D is deuterium) single crystals.« less

The 2√{3}×2√{3}R30 surface reconstruction of alkali/Si(1 1 1):B semiconducting surfaces

NASA Astrophysics Data System (ADS)

Tournier-Colletta, C.; Chaput, L.; Tejeda, A.; Cardenas, L. A.; Kierren, B.; Malterre, D.; Fagot-Revurat, Y.; Fèvre, P. Le; Bertran, F.; Taleb-Ibrahimi, A.

2013-02-01

The surface structure of alkali doped Si(1 1 1):B ultra-thin films has been studied by low-energy electron diffraction (LEED), X-ray photoemission spectroscopy (XPS) and scanning tunneling microscopy (STM). A comparative study of K/Si(1 1 1)-3 × 1 and K/Si(1 1 1):B-2√{3}×2√{3}R30 interfaces allowed us to determine the saturation coverage to be 0.5 monolayer in the later case. The 2√{3}-surface reconstruction is shown to be a common property of pure K, Rb, Cs materials and K0.4Rb0.6 alloys but progressively disappears if Rb is replaced by Ca. Taking into account the existence of two distinct boron sites in the ratio 1/3 as seen from B-1s core levels spectra, LAPW-DFT calculations have been carried out in order to optimize the atomic structure. As a result, alkali adatoms are shown to form trimers leading to a large modulation of the Sisbnd B bonds accompanied by an inhomogeneous doping of the dangling bonds in agreement with voltage dependent STM images.

Anisotropic diffusion at the field scale in a 4-year multi-tracer diffusion and retention experiment - I: Insights from the experimental data

NASA Astrophysics Data System (ADS)

Gimmi, Thomas; Leupin, Olivier X.; Eikenberg, Jost; Glaus, Martin A.; Van Loon, Luc R.; Waber, H. Niklaus; Wersin, Paul; Wang, Hao A. O.; Grolimund, Daniel; Borca, Camelia N.; Dewonck, Sarah; Wittebroodt, Charles

2014-01-01

Claystones are considered worldwide as barrier materials for nuclear waste repositories. In the Mont Terri underground research laboratory (URL), a nearly 4-year diffusion and retention (DR) experiment has been performed in Opalinus Clay. It aimed at (1) obtaining data at larger space and time scales than in laboratory experiments and (2) under relevant in situ conditions with respect to pore water chemistry and mechanical stress, (3) quantifying the anisotropy of in situ diffusion, and (4) exploring possible effects of a borehole-disturbed zone. The experiment included two tracer injection intervals in a borehole perpendicular to bedding, through which traced artificial pore water (APW) was circulated, and a pressure monitoring interval. The APW was spiked with neutral tracers (HTO, HDO, H2O-18), anions (Br, I, SeO4), and cations (Na-22, Ba-133, Sr-85, Cs-137, Co-60, Eu-152, stable Cs, and stable Eu). Most tracers were added at the beginning, some were added at a later stage. The hydraulic pressure in the injection intervals was adjusted according to the measured value in the pressure monitoring interval to ensure transport by diffusion only. Concentration time-series in the APW within the borehole intervals were obtained, as well as 2D concentration distributions in the rock at the end of the experiment after overcoring and subsampling which resulted in ∼250 samples and ∼1300 analyses. As expected, HTO diffused the furthest into the rock, followed by the anions (Br, I, SeO4) and by the cationic sorbing tracers (Na-22, Ba-133, Cs, Cs-137, Co-60, Eu-152). The diffusion of SeO4 was slower than that of Br or I, approximately proportional to the ratio of their diffusion coefficients in water. Ba-133 diffused only into ∼0.1 m during the ∼4 a. Stable Cs, added at a higher concentration than Cs-137, diffused further into the rock than Cs-137, consistent with a non-linear sorption behavior. The rock properties (e.g., water contents) were rather homogeneous at the centimeter scale, with no evidence of a borehole-disturbed zone. In situ anisotropy ratios for diffusion, derived for the first time directly from field data, are larger for HTO and Na-22 (∼5) than for anions (∼3-4 for Br and I). The lower ionic strength of the pore water at this location (∼0.22 M) as compared to locations of earlier experiments in the Mont Terri URL (∼0.39 M) had no notable effect on the anion accessible pore fraction for Cl, Br, and I: the value of 0.55 is within the range of earlier data. Detailed transport simulations involving different codes will be presented in a companion paper.

Cloning and functional characterization of the high-affinity K+ transporter HAK1 of pepper.

PubMed

Martínez-Cordero, M Angeles; Martínez, Vicente; Rubio, Francisco

2004-10-01

High-affinity K+ uptake in plants plays a crucial role in K+ nutrition and different systems have been postulated to contribute to the high-affinity K+ uptake. The results presented here with pepper (Capsicum annum) demonstrate that a HAK1-type transporter greatly contributes to the high-affinity K+ uptake observed in roots. Pepper plants starved of K+ for 3 d showed high-affinity K+ uptake (Km of 6 microM K+) that was very sensitive to NH and their roots expressed a high-affinity K+ transporter, CaHAK1, which clusters in group I of the KT/HAK/KUP family of transporters. When expressed in yeast ( Saccharomyces cerevisiae ), CaHAK1 mediated high-affinity K+ and Rb+ uptake with Km values of 3.3 and 1.9 microM, respectively. Rb+ uptake was competitively inhibited by micromolar concentrations of NH and Cs+, and by millimolar concentrations of Na+.

The chemical signatures of progressive dehydration stages in subducted serpentinites

NASA Astrophysics Data System (ADS)

Pettke, T.; Spandler, C.; Kodolanyi, J.; Scambelluri, M.

2009-04-01

Fluids mediate chemical cycling in subduction zones. Nonetheless, the chemistry of serpentinite-dehydration fluids from down-going slabs and their chemical effects on ascent are only very poorly constrained. We report new data on discontinuous dehydration reactions, including the measurement of individual fluid inclusions in prograde minerals from natural occurrences, and one case study tracing the infiltration of serpentinite-derived fluid in mafic eclogite. Together, these studies demonstrate that serpentinite-derived fluids are commonly dilute, but that there may be selected trace element abundances (and ratios ?) that characterize such fluid provenance. Brucite dehydration represents the first relevant liberation of crystal-bound water from serpentinites formed on the ocean floor (ocean floor mantle hydration chemistry is addressed in Kodolanyi et al., this session). Discordant olivine-Ti-clinohumite-antigorite-clinopyroxene-magnetite veins in ca. 2.3 GPa antigorite serpentinites of the Erro Tobbio in the Ligurian Alps, Italy, formed from aqueous, dilute fluids containing Li, Sr, Ba, Rb, Pb as determined on texturally-early fluid inclusions in olivine. This prograde olivine preserves high Ni (1500 - 3000 µg/g) and is identified most readily by elevated Li (1-20 µg/g), B (1-20 µg/g) and Mn contents. Aqueous fluid inclusions in some clinopyroxene (Cpx) of the same veins host variably (sometimes highly) saline fluid inclusions, interpreted to represent the "spent" fluid after formation of hydrous vein minerals (chlorite, antigorite). Vein bulk-rock trace-element concentrations show enrichment in Ti, Ba, Nb, Li, HREE and Cu relative to the wall rocks, accompanied by depletion in Cr. This mostly reflects the mineral transformations (sources / sinks) occurring at this stage of serpentinite dehydration. Antigorite-breakdown is arguably the most prominent water release from down-going slabs. Olivine-orthopyroxene-chlorite rocks at Cerro del Almirez (Spain), recording this dehydration event, contain olivine-hosted polyphase inclusions interpreted to represent fluid inclusions trapped during antigorite breakdown. Preliminary compositional data show enrichments in B, Cs, Pb, Li, Sr, Rb, K, Ba (decreasing order) and depletions in Ca, Ti, La relative to primitive mantle, closely corresponding to the incompatible element pattern of typical island arc lavas. Transfer of such fluids to the melting source of island arc magmas may be critical to developing their distinctive trace element signatures. Omphacite-rich (± garnet, rutile, talc and zircon) veins cutting eclogite (Fe-Ti gabbro protolith, Monviso, W Italian Alps) record serpentinite-derived fluid pathways though the subducted slab at ca. 70 km depth. Although these veins largely formed by local eclogite-derived fluids, they also preserve discrete generations of vein minerals enriched in Mg, Cr, Ni, B, As and Sb, and zircon with elevated Epsilon(Hf) compared to host-rock eclogite zircon. These chemical and isotopic characteristics suggest external fluid input, from serpentinite dehydration. Moreover, distinctive oscillatory or irregular Cr zonations observed in omphacite, garnet and rutile from the veins are interpreted to record episodic fracturing and fluid infiltration over >10 m along transient brittle fractures at high pressures. Our current data suggest that dehydration fluid pervades the rock at the site of liberation, and that episodic fluid escape from the dehydration site may be effectively channelized. This supports growing evidence for highly focused reactive fluid flow through slabs. Robust constraints on the chemical composition and nature of dehydration fluids from serpentinites and how they evolve during ascent may greatly aid in recognizing such features from outcrop to thin-section scales, in turn providing us with more comprehensive sample material to advance our understanding on fluid-mediated cycling in subduction zones. Reference Kodolanyi et al., this session

Tourmaline orbicules in peraluminous monzogranites of Argentina: A study case of fluid-rock interaction between leucogranite and country-rock metasediments

NASA Astrophysics Data System (ADS)

Lira, Raúl; Poklepovic, María F.

2017-12-01

Tourmaline orbicules hosted in peraluminous granites are documented worldwide. Seven occurrences were identified in Argentina. Petrography, mineral chemistry, whole-rock geochemistry mass balance and microthermometric studies were performed in orbicules formed at the cupola of a peraluminous A-type leucogranite (Los Riojanos pluton), as well as complementary investigation was achieved in other orbicules of similar geological setting. Mass balance computations in zoned orbicules consistently confirmed immobility of Si both in core and halo, immobility of K and little loss of Al during halo reactions. Elements gained and lost in the schorl-rich core are Fe, Al, Mg, Ti, Ba, Sr, Y and Zr, and Na, K, Rb and Nb, respectively; in the halo, K, Ba, Sr, Y, Zr and locally CaO, were gained, and Fe, Mg, Na, Al, Rb and Nb were lost. The schorl-rich core is enriched in LREE relative to the leucogranite host. A temperature-salinity plot from fluid inclusion data delineates a magmatic-meteoric mixing trend of diluting salinity with descending temperature. Computed δDH20 values from Los Riojanos orbicule schorl suggest magmatic and magmatic-meteoric mixed origins. In Los Riojanos, mass balance constraints suggest that Fe, Mg, Ba, Sr and metallic traces like Zn and V (±Pb) were most likely derived from country-rock schists and gneisses through fluid-rock exchange reactions. A late magmatic-, volatile-rich- fluid exsolution scenario for the formation of orbicules is envisaged. Schorl crystallization was likely delayed to the latest stages of leucogranite consolidation, not only favored by the high diffusivity of B2O3 preferentially partitioned into the exsolved aqueous-rich fluid, but also likely limited to the low availability of Fe and Mg from the scarce granitic biotite, and to the high F- content of the melt. The spatial confination of orbicules to the contact zone granite-metasediments suggests that orbicules were not formed until exsolved fluids reached the boundary with the biotite-rich country-rock.

A first-principles based study of ns2 containing ternary iodides and their possibility of scintillation

NASA Astrophysics Data System (ADS)

Kang, Byungkyun; Fang, C. M.; Biswas, Koushik

2016-10-01

A recently investigated scintillator material CsBa2I5 showed promising properties when activated with ns2 ions In+, Tl+ or the lanthanide Eu2+. This sparked our interest in an analogous group of materials, e.g. InBa2I5 or TlBa2I5 where the ns2 ion is part of the crystal framework, replacing the alkali ion. Many of these compounds of the type AB2X5 (X  =  halogen) have been previously synthesized and have interesting stereochemical activity. Using density functional calculations we have studied the stable monoclinic phase of the aforementioned ns2 containing iodides. One objective is to explore them as scintillators where the ns2 ions, now appearing as part of the crystal, play a central role. Compared to CsBa2I5, their reduced fundamental band gap and possibility of higher light yield may be attributed to an induced degree of covalency in the ns2-I bonds. The valence and conduction band edges have discernible contributions from the ns2 ions’ s and p orbitals which is crucial in carrier localization. The antibonding Ga or In s sates near valence edge may be a favored site for a hole trap, as against a {{V}k} center. Additional differences among the ns2 compounds lead to qualitatively different self-trapped excitons that may fundamentally affect luminescence. The possibility of fast electron capture at the ns2 sites and the prospect of self-activated scintillation via ns2-p  →  {{V}k} or ns2-p  →  ns2-s transitions may draw interest in related applications.

Origin of increased terrigenous supply to the NE South American continental margin during Heinrich Stadial 1 and the Younger Dryas

NASA Astrophysics Data System (ADS)

Zhang, Yancheng; Chiessi, Cristiano M.; Mulitza, Stefan; Zabel, Matthias; Trindade, Ricardo I. F.; Hollanda, Maria Helena B. M.; Dantas, Elton L.; Govin, Aline; Tiedemann, Ralf; Wefer, Gerold

2015-12-01

We investigate the redistribution of terrigenous materials in the northeastern (NE) South American continental margin during slowdown events of the Atlantic Meridional Overturning Circulation (AMOC). The compilation of stratigraphic data from 108 marine sediment cores collected across the western tropical Atlantic shows an extreme rise in sedimentation rates off the Parnaíba River mouth (about 2°S) during Heinrich Stadial 1 (HS1, 18-15 ka). Sediment core GeoB16206-1, raised offshore the Parnaíba River mouth, documents relatively constant 143Nd/144Nd values (expressed as εNd(0)) throughout the last 30 ka. Whereas the homogeneous εNd(0) data support the input of fluvial sediments by the Parnaíba River from the same source area directly onshore, the increases in Fe/Ca, Al/Si and Rb/Sr during HS1 indicate a marked intensification of fluvial erosion in the Parnaíba River drainage basin. In contrast, the εNd(0) values from sediment core GeoB16224-1 collected off French Guiana (about 7°N) suggest Amazon-sourced materials within the last 30 ka. We attribute the extremely high volume of terrigenous sediments deposited offshore the Parnaíba River mouth during HS1 to (i) an enhanced precipitation in the catchment region and (ii) a reduced North Brazil Current, which are both associated with a weakened AMOC.

High pressure far infrared spectroscopy of ionic solids

NASA Technical Reports Server (NTRS)

Lowndes, R. P.

1974-01-01

A high-pressure far-infrared cell operating at up to truly hydrostatic pressures of 8 kbar is described and used to determine the anharmonic self-energies associated with the transverse optic modes of ionic solids in which q approximately equals zero. The cell allows far-infrared studies in the spectral range below 120 reciprocal cm. The transverse optic modes were investigated to determine their mode Gruneisen constants and the pressure dependence of their inverse lifetimes in RbI, CsI, and TlCl.

Major and trace element concentrations in samples from 72275 and 72255. [chemical composition of lunar rocks

NASA Technical Reports Server (NTRS)

Haskin, L. A.; Blanchard, D. P.; Korotev, R.; Jacobs, J. W.; Brannon, J. A.; Herrmann, A. G.

1974-01-01

Analytical data have been obtained for Co, Sc, Hf, Zn, Cr, Ga, Rb, Cs, Ni, major elements, and rare earth elements in eight samples from boulder 1. The data for trace elements were obtained by radiochemical neutron activation analysis. Major elements, except Na and Mn, were obtained by atomic absorption spectral photometry. Values for Na and Mn were obtained by neutron activation analysis of the same powder that was later dissolved to provide the atomic absorption analyses.

Chemical studies of differentiated meteorites. I - Labile trace elements in Antarctic and non-Antarctic eucrites

NASA Technical Reports Server (NTRS)

Paul, Rick L.; Lipschutz, Michael E.

1990-01-01

Element contents of Ag, Au, Bi, Cd, Co, Cs, Ga, In, Rb, Sb, Se, Te, Tl, U, and Zn were analyzed, using RNAA, in 25 Antarctic and nine non-Antarctic eucrites to determine whether these two populations differ significantly in thermal history and derive from the same or different eucrite parent body. Data for these 15 elements indicate that basaltic Antarctic and non-Antarctic eucrite populations reflect the same genetic processes and, hence, come from the same parent asteroid.

Data on photoneutron reactions from various experiments for {sup 133}Cs, {sup 138}Ba and {sup 209}Bi nuclei

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

Varlamov, V. V., E-mail: Varlamov@depni.sinp.msu.ru; Ishkhanov, B. S.; Orlin, V. N.

2016-07-15

Basic methods for determining cross sections for photoneutron partial reactions are examined. They are obtained directly in experiments with quasimonoeneregetic annihilation photons or from the cross section for the (γ, xn) = (γ, 1n) + 2(γ, 2n) + 3(γ, 3n) +... neutron-yield reaction in experiments with bremsstrahlung photons by introducing corrections based on statistical nuclear-reaction theory. The difference in the conditions of these experiments, which leads to discrepancies between their results because of sizable systematic errors, is analyzed. Physical criteria are used to study the reliability of data on the photodisintegration of {sup 133}Cs, {sup 138}Ba, and {sup 209}Bi nuclei.more » The cross sections for partial and total reactions satisfying the reliability criteria are evaluated within the experimental–theoretical method (σ{sup eval}(γ, in) = F{sub i}{sup theor} × σ{sup expt}(γ, xn)) on the basis of the experimental cross sections σ{sup expt}(γ, xn) and the results of the calculations within the combined model of photonuclear reactions.« less

Spatial and temporal distribution of metals in suspended particulate matter of the Kali estuary, India

NASA Astrophysics Data System (ADS)

Suja, S.; Kessarkar, Pratima M.; Fernandes, Lina L.; Kurian, Siby; Tomer, Arti

2017-09-01

Major (Al, Fe, Mn, Ti, Mg) and trace (Cu, Zn, Pb, Cr, Ni, Co, Zr, Rb, Sr, Ba, Li, Be, Sc, V, Ga, Nb, Mo, Sn, Sb, Cs, Hf, Ta, Bi, Th, U) elements and particulate organic carbon (POC) concentrations in surface suspended particulate matter (SPM) of the Kali estuary, (central west coast of India) were studied during the pre-monsoon, monsoon and post monsoon seasons to infer estuarine processes, source of SPM and Geoaccumulation Index (Igeo) assigned pollutionIgeo levels. Distribution of SPM indicates the presence of the estuarine turbidity maximum (ETM) during all three seasons near the river mouth and a second ETM during the post monsoon time in the upstream associated with salinities gradient. The SPM during the monsoon is finer grained (avg. 53 μm), characterized by uniformly low normalized elemental concentration, whereas the post and pre monsoon are characterized by high normalized elemental concentration with coarser grain size (avg. 202 μm and 173 μm respectively) with highest ratios in the upstream estuary. The elemental composition and principal component analysis for the upstream estuary SPM support more contribution from the upstream catchment area rocks during the monsoon season; there is additional contribution from the downstream catchment area during the pre and post monsoon period due to the tidal effect. The Kali estuarine SPM has higher Al, Fe, Mn, Ti, Mg, Ni, Co, Ba, Li and V with respect to Average World River SPM (WRSPM). Igeo values for the SPM indicate Kali Estuary to be severely enriched with Mn and moderately enriched with Cu, Zn, Ni, Co, U and Mo in the upstream estuary during pre and post monsoon seasons. Seasonal changes in salinity gradient (reduced freshwater flow due to closing of the dam gates), reduced velocity at meandering region of the estuary and POC of 1.6-2.3% resulted in co-precipitation of trace elements that were further fortified by flocculation and coagulation throughout the water column resulting in metal trapping in the upstream region.

Geosphere-biosphere circulation of chemical elements in soil and plant systems from a 100 km transect from southern central Norway.

PubMed

Reimann, Clemens; Fabian, Karl; Flem, Belinda; Andersson, Malin; Filzmoser, Peter; Englmaier, Peter

2018-05-17

Geochemical element separation is studied in 14 different sample media collected at 41 sites along an approximately 100-km long transect north of Oslo. At each site, soil C and O horizons and 12 plant materials (birch/spruce/cowberry/blueberry leaves/needles and twigs, horsetail, braken fern, pine bark and terrestrial moss) were sampled. The observed concentrations of 29 elements (K, Ca, P, Mg, Mn, S, Fe, Zn, Na, B, Cu, Mo, Co, Al, Ba, Rb, Sr, Ti, Ni, Pb, Cs, Cd, Ce, Sn, La, Tl, Y, Hg, Ag) were used to investigate soil-plant relations, and to evaluate the element differentiation between different plants, or between foliage and twigs of the same plant. In relation to the soil C horizon, the O horizon is strongly enriched (O/C ratio > 5) in Ag, Hg, Cd, Sn, S and Pb. Other elements (B, K, Ca, P, S, Mn) show higher concentrations in the plants than in the substrate represented by the C horizon, and often even higher concentrations than in the soil O horizon. Elements like B, K, Ca, S, Mg, P, Ba, and Cu are well tuned to certain concentration levels in most of the plants. This is demonstrated by their lower interquartile variability in the plants than in the soil. Cross-plots of element concentration, variance, and ratios, supported by linear discrimination analysis, establish that different plants are marked by their individual element composition, which is separable from, and largely independent of the natural substrate variability across the Gjøvik transect. Element allocation to foliage or twigs of the same plants can also be separated and thus dominantly depend on metabolism, physiology, and structure linked to biological functions, and only to a lesser degree on the substrate and environmental background. The results underline the importance of understanding the biological mechanisms of plant-soil interaction in order to correctly quantify anthropogenic impact on soil and plant geochemistry. Copyright © 2018 Elsevier B.V. All rights reserved.

Barium isotope abundances in meteorites and their implications for early Solar System evolution

NASA Astrophysics Data System (ADS)

Bermingham, K. R.; Mezger, K.; Scherer, E. E.; Horan, M. F.; Carlson, R. W.; Upadhyay, D.; Magna, T.; Pack, A.

2016-02-01

Several nucleosynthetic processes contributed material to the Solar System, but the relative contributions of each process, the timing of their input into the solar nebula, and how well these components were homogenized in the solar nebula remain only partially constrained. The Ba isotope system is particularly useful in addressing these issues because Ba isotopes are synthesized via three nucleosynthetic processes (s-, r-, p-process). In this study, high precision Ba isotope analyses of 22 different whole rock chondrites and achondrites (carbonaceous chondrites, ordinary chondrites, enstatite chondrites, Martian meteorites, and eucrites) were performed to constrain the distribution of Ba isotopes on the regional scale in the Solar System. A melting method using aerodynamic levitation and CO2-laser heating was used to oxidize SiC, a primary carrier of Ba among presolar grains in carbonaceous chondrites. Destruction of these grains during the fusion process enabled the complete digestion of these samples. The Ba isotope data presented here are thus the first for which complete dissolution of the bulk meteorite samples was certain. Enstatite chondrites, ordinary chondrites, and all achondrites measured here possess Ba isotope compositions that are not resolved from the terrestrial composition. Barium isotope anomalies are evident in most of the carbonaceous chondrites analyzed, but the 135Ba anomalies are generally smaller than previously reported for similarly sized splits of CM2 meteorites. Variation in the size of the 135Ba anomaly is also apparent in fused samples from the same parent body (e.g., CM2 meteorites) and in different pieces from the same meteorite (e.g., Orgueil, CI). Here, we investigate the potential causes of variability in 135Ba, including the contribution of radiogenic 135Ba from the decay of 135Cs and incomplete homogenization of the presolar components on the <0.8 g sample scale.

Thermoelectric transport properties of BaBiTe{sub 3}-based materials

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

Zhou, Yiming; Zhao, Li-Dong, E-mail: zhaolidong@buaa.edu.cn

BaBiTe{sub 3}, a material with low thermal conductivity, is an inferior thermoelectric material due to the poor electrical properties originated from its narrow band gap. We choose two types of dopants, K and La, trying to optimize its electrical transport properties. The minority carriers, which harm the Seebeck coefficient in this system, are suppressed by La doping. With the increase of both electrical conductivity and Seebeck coefficient, the power factor of 3% La doped BaBiTe{sub 3} reaches 3.7 μW cm{sup −1} K{sup −2} which increased by 40% from undoped BaBiTe{sub 3}. Besides high power factor, the thermal conductivity is alsomore » reduced in it. Eventually, a high ZT value, 0.25 at 473 K, for n-type BaBiTe{sub 3} is achieved in 3% La doped BaBiTe{sub 3}. - Graphical abstract: BaBiTe{sub 3} possesses a low thermal conductivity. However, it is an inferior thermoelectric material due to the poor electrical properties originated from its narrow band gap. A high ZT value of 0.25 at 473 K for n-type BaBiTe{sub 3} can be achieved through optimizing electrical transport properties via La doping. - Highlights: • BaBiTe{sub 3} is an analogue of these promising thermoelectric materials: such as CsBi{sub 4}Te{sub 6} and K{sub 2}Bi{sub 8}Se{sub 13}, etc. • BaBiTe{sub 3} possesses a low thermal conductivity. • La is an effective dopant to enhance electrical transport properties. • A high ZT value of 0.25 at 473 K can be achieved in n-type La-doped BaBiTe{sub 3}.« less

Kir2.1 encodes the inward rectifier potassium channel in rat arterial smooth muscle cells

PubMed Central

Bradley, Karri K; Jaggar, Jonathan H; Bonev, Adrian D; Heppner, Thomas J; Flynn, Elaine RM; Nelson, Mark T; Horowitz, Burton

1999-01-01

The molecular nature of the strong inward rectifier K+ channel in vascular smooth muscle was explored by using isolated cell RT-PCR, cDNA cloning and expression techniques.RT-PCR of RNA from single smooth muscle cells of rat cerebral (basilar), coronary and mesenteric arteries revealed transcripts for Kir2.1. Transcripts for Kir2.2 and Kir2.3 were not found.Quantitative PCR analysis revealed significant differences in transcript levels of Kir2.1 between the different vascular preparations (n = 3; P < 0.05). A two-fold difference was detected between Kir2.1 mRNA and β-actin mRNA in coronary arteries when compared with relative levels measured in mesenteric and basilar preparations.Kir2.1 was cloned from rat mesenteric vascular smooth muscle cells and expressed in Xenopus oocytes. Currents were strongly inwardly rectifying and selective for K+.The effect of extracellular Ba2+, Ca2+, Mg2+ and Cs2+ ions on cloned Kir2.1 channels expressed in Xenopus oocytes was examined. Ba2+ and Cs+ block were steeply voltage dependent, whereas block by external Ca2+ and Mg2+ exhibited little voltage dependence. The apparent half-block constants and voltage dependences for Ba2+, Cs+, Ca2+ and Mg2+ were very similar for inward rectifier K+ currents from native cells and cloned Kir2.1 channels expressed in oocytes.Molecular studies demonstrate that Kir2.1 is the only member of the Kir2 channel subfamily present in vascular arterial smooth muscle cells. Expression of cloned Kir2.1 in Xenopus oocytes resulted in inward rectifier K+ currents that strongly resemble those that are observed in native vascular arterial smooth muscle cells. We conclude that Kir2.1 encodes for inward rectifier K+ channels in arterial smooth muscle. PMID:10066894

Interpreting stream sediment fingerprints against primary and secondary source signatures in agricultural catchments

NASA Astrophysics Data System (ADS)

Blake, Will H.; Haley, Steve; Smith, Hugh G.; Taylor, Alex; Goddard, Rupert; Lewin, Sean; Fraser, David

2013-04-01

Many sediment fingerprinting studies adopt a black box approach to source apportionment whereby the properties of downstream sediment are compared quantitatively to the geochemical fingerprints of potential catchment sources without consideration of potential signature development or modification during transit. Working within a source-pathway-receptor framework, this study aimed to undertake sediment source apportionment within 6 subcatchments of an agricultural river basin with specific attention to the potential role of contaminants (vehicle emissions and mine waste) in development of stream sediment signatures. Fallout radionuclide (FRN) and geochemical fingerprinting methods were adopted independently to establish source signatures for primary sediment sources of surface and subsurface soil materials under various land uses plus reworked mine and 'secondary' soil material deposited, in transit, along road networks. FRN data demonstrated expected variability between surface soil (137Cs = 14 ± 3 Bq kg-1; 210Pbxs = 40 ± 7 Bq kg-1) and channel bank materials (137Cs = 3 ± 1 Bq kg-1; 210Pbxs = 24 ± 5 Bq kg-1) but road transported soil material was considerably elevated in 210Pbxs (up to 673 ± 51 Bq kg-1) due to sediment interaction with pluvial surface water within the road network. Geochemical discrimination between surface and subsurface soil materials was dominated by alkaline earth and alkali metals e.g. Ba, Rb, Ca, K, Mg which are sensitive to weathering processes in soil. Magnetic susceptibility and heavy metals were important discriminators of road transported material which demonstrated transformation of the signatures of material transported via the road network. Numerical unmixing of stream sediment indicated that alongside channel bank erosion, road transported material was an important component in some systems in accord with FRN evidence. While mining spoil also ranked as a significant source in an affected catchment, perhaps related to legacy sediment, the potential role of dissolved metal leaching and subsequent sediment-water interaction within the channel on signature modification remained unclear. Consideration of sediment signature modification en route from primary source to stream elucidated important information regarding sediment transfer pathways and dynamics relevant to sediment management decisions. Further work on sediment-water interactions and potential for signature transformation in the channel environment is required.

Fission product release from fuel under LWR accident conditions

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

Osborne, M.F.; Lorenz, R.A.; Norwood, K.S.

Three tests have provided additional data on fission product release under LWR accident conditions in a temperature range (1400 to 2000/sup 0/C). In the release rate data are compared with curves from a recent NRC-sponsored review of available fission product release data. Although the iodine release in test HI-3 was inexplicably low, the other data points for Kr, I, and Cs fall reasonably close to the corresponding curve, thereby tending to verify the NRC review. The limited data for antimony and silver release fall below the curves. Results of spark source mass spectrometric analyses were in agreement with the gammamore » spectrometric results. Nonradioactive fission products such as Rb and Br appeared to behave like their chemical analogs Cs and I. Results suggest that Te, Ag, Sn, and Sb are released from the fuel in elemental form. Analysis of the cesium and iodine profiles in the thermal gradient tube indicates that iodine was deposited as CsT along with some other less volatile cesium compound. The cesium profiles and chemical reactivity indicate the presence of more than one cesium species.« less

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

Charkin, Dmitri O.; Black, Cameron; Downie, Lewis J.

Two new rare-earth – alkali – tellurium oxide halides were synthesized by a salt flux technique and characterized by single-crystal X-ray diffraction. The structures of the new compounds Cs{sub 7}Sm{sub 11}[TeO{sub 3}]{sub 12}Cl{sub 16} (I) and Rb{sub 7}Nd{sub 11}[TeO{sub 3}]{sub 12}Br{sub 16} (II) (both tetragonal, space group I4/mcm) correspond to the sequence of [MLn{sub 11}(TeO{sub 3}){sub 12}] and [M{sub 6}X{sub 16}] layers and bear very strong similarities to those of known selenite analogs. We discuss the trends in similarities and differences in compositions and structural details between the Se and Te compounds; more members of the family are predicted. -more » Graphical abstract: Two new rare-earth – alkali – tellurium oxide halides were predicted and synthesized. - Highlights: • Two new rare-earth – alkali – tellurium oxide halides were synthesized. • They adopt slab structure of rare earth-tellurium-oxygen and CsCl-like slabs. • The Br-based CsCl-like slabs have been observed first in this layered family.« less

Lorentz-symmetry test at Planck-scale suppression with nucleons in a spin-polarized 133Cs cold atom clock

NASA Astrophysics Data System (ADS)

Pihan-Le Bars, H.; Guerlin, C.; Lasseri, R.-D.; Ebran, J.-P.; Bailey, Q. G.; Bize, S.; Khan, E.; Wolf, P.

2017-04-01

We introduce an improved model that links the frequency shift of the 133Cs hyperfine Zeeman transitions |F =3 ,mF ⟩↔|F =4 ,mF ⟩ to the Lorentz-violating Standard Model extension (SME) coefficients of the proton and neutron. The new model uses Lorentz transformations developed to second order in boost and additionally takes the nuclear structure into account, beyond the simple Schmidt model used previously in Standard Model extension analyses, thereby providing access to both proton and neutron SME coefficients including the isotropic coefficient c˜T T. Using this new model in a second analysis of the data delivered by the FO2 dual Cs/Rb fountain at Paris Observatory and previously analyzed in [1], we improve by up to 13 orders of magnitude the present maximum sensitivities for laboratory tests [2] on the c˜Q, c˜T J, and c˜T T coefficients for the neutron and on the c˜Q coefficient for the proton, reaching respectively 10-20, 10-17, 10-13, and 10-15 GeV .

Pharmacological and gene regulation properties point to the SlHAK5 K+ transporter as a system for high-affinity Cs+ uptake in tomato plants.

PubMed

Ródenas, Reyes; Nieves-Cordones, Manuel; Rivero, Rosa M; Martinez, Vicente; Rubio, Francisco

2018-04-01

Potassium (K + ) and cesium (Cs + ) are chemically similar but while K + is an essential nutrient, Cs + can be toxic for living organisms, plants included. Two different situations could lead to problems derived from the presence of Cs + in agricultural systems: (1) presence of Cs + at high concentrations that could produce toxic effects on plants, (2) presence of micromolar concentrations of radiocesium, which can be accumulated in the plant and affect animal and human health through the food chain. While K + uptake has been well described in tomato plants, information on molecular mechanisms involved in Cs + accumulation in this species is absent. Here, we show that in tomato plants, high concentrations of Cs + produce deficiency of K + but do not induce high-affinity K + uptake or the gene encoding the high-affinity K + transporter SlHAK5. At these concentrations, Cs + uptake takes place through a Ca 2+ -sensitive pathway, probably a non-selective cation channel. At micromolar concentrations, Cs + is accumulated by a high-affinity uptake system upregulated in K + -starved plants. This high-affinity Cs + uptake shares features with high-affinity K + uptake. It is sensitive to NH 4 + and insensitive to Ba 2+ and Ca 2+ and its presence parallels the pattern of SlHAK5 expression. Moreover, blockers of reactive oxygen species and ethylene action repress SlHAK5 and negatively regulate both high-affinity K + and Cs + uptake. Thus, we propose that SlHAK5 contributes to Cs + uptake from micromolar concentrations in tomato plants and can constitute a pathway for radiocesium transfer from contaminated areas to the food chain. © 2017 Scandinavian Plant Physiology Society.

Barium from a mini r-process in supernovae

NASA Technical Reports Server (NTRS)

Heymann, D.

1983-01-01

McCulloch and Wasserburg (1978) have reported nonlinear isotopic anomalies in barium for two Ca-Al-rich inclusions of the Allende carbonaceous chondrite, known as EK-1-4-1 and C-1. In an attempt to account for these anomalies, it has been proposed that Ba from an r-process of nucleosynthesis, containing Ba-135 and Ba-137, was injected into the primeval color system but was not totally homogenized. Questions arise in connection with the relations of Xe isotopes in carbonaceous chondrites. This has prompted Heymann and Dziczkaniec (1979, 1980, 1981) to study the formation of r-Xe, r-Kr, and r-Te by the mini r-process which is thought to occur in the O, Ne-rich shells of Type II supernovae. Lee et al. (1979) have studied the formation of r-Ba, r-Nd, and r-Sm by the same process. Certain differences regarding the approaches used by Lee et al. and by Heymann and Dziczkaniec make it necessary to restudy the work of Lee et al. Attention is given to the survival probabilities of nuclear species of interest, taking into accounts the elements Cs, Ba, I, and Xe.

Physicochemical properties and the concentration of anions, major and trace elements in groundwater, treated drinking water and bottled drinking water in Najran area, KSA

NASA Astrophysics Data System (ADS)

Brima, Eid I.

2017-03-01

Basic information about major elements in bottled drinking water is provided on product labels. However, more information is needed about trace elements in bottled drinking water and other sources of drinking water to assess its quality and suitability for drinking. This is the first such study to be carried out in Najran city in the Kingdom of Saudi Arabia (KSA). A total of 48 water samples were collected from different sources comprising wells, stations for drinking water treatment and bottled drinking water (purchased from local supermarkets). The concentrations of 24 elements [aluminum (Al), arsenic (As), barium (Ba), calcium (Ca), cadmium (Cd), cobalt (Co), chromium (Cr), cesium (Cs), copper (Cu), iron (Fe), potassium (K), magnesium (Mg), manganese (Mn), molydenum (Mo), sodium (Na), nickel (Ni), lead (Pb), rubidium (Rb), selenium (Se), strontium (Sr), titanium (Ti), vanadium (V), uranium (U) and zinc (Zn)] were determined by inductively coupled plasma-mass spectrometry (ICP-MS). Anions (chlorine (Cl-), fluoride (F-), sulfate (SO4 2-) and nitrate (NO3 -) were determined by ion chromatography (IC). Electrical conductivity (EC), pH, total dissolved salts (TDS) and total hardness (TH) were also measured. All parameters of treated drinking water and bottled drinking water samples did not exceed the World Health Organization (WHO) 2008, US Environmental Protection Agency (USEPA 2009), Gulf Cooperation Council Standardization Organization (GSO) 2008 and Saudi Arabian Standards Organization (SASO) 1984 recommended guidelines. It is noteworthy that groundwater samples were not used for drinking purpose. This study is important to raise public knowledge about drinking water, and to promote public health.

Epithermal Neutron Activation Analysis of the Asian Herbal Plants

NASA Astrophysics Data System (ADS)

Baljinnyam, N.; Jugder, B.; Norov, N.; Frontasyeva, M. V.; Ostrovnaya, T. M.; Pavlov, S. S.

2011-06-01

Asian medicinal herbs Chrysanthemum (Spiraea aquilegifolia Pall.) and Red Sandalwood (Pterocarpus Santalinus) are widely used in folk and Ayurvedic medicine for healing and preventing some diseases. The modern medical science has proved that the Chrysanthemum (Spiraea aquilegifolia Pall.) possesses the following functions: reducing blood press, dispelling cancer cell, coronary artery's expanding and bacteriostating and Red Sandalwood (Pterocarpus Santalinus) is recommended against headache, toothache, skin diseases, vomiting and sometimes it is taken for treatment of diabetes. Species of Chrysanthemums were collected in the north-eastern and central Mongolia, and the Red Sandalwood powder was imported from India. Samples of Chrysanthemums (branches, flowers and leaves) (0.5 g) and red sandalwood powder (0.5 g) were subjected to the multi-element instrumental neutron activation analysis using epithermal neutrons (ENAA) at the IBR-2 reactor, Frank Laboratory of Neutron Physics (FLNP) JINR, Dubna. A total of 41 elements (Na, Mg, Al, Cl, K, Ca, Sc, V, Cr, Mn, Fe, Co, Ni, Zn, As, Se, Br, Rb, Sr, Zr, Mo, Cd, Cs, Ba, La, Hf, Ta, W, Sb, Au, Hg, Ce, Nd, Sm, Eu, Tb, Dy, Yb, Th, U, Lu) were determined. For the first time such a large group of elements was determined in the herbal plants used in Mongolia. The quality control of the analytical results was provided by using certified reference material Bowen Cabbage. The results obtained are compared to the "Reference plant» data (B. Markert, 1992) and interpreted in terms of excess of such elements as Se, Cr, Ca, Fe, Ni, Mo, and rare earth elements.

Trace elements in hazardous mineral fibres.

PubMed

Bloise, Andrea; Barca, Donatella; Gualtieri, Alessandro Francesco; Pollastri, Simone; Belluso, Elena

2016-09-01

Both occupational and environmental exposure to asbestos-mineral fibres can be associated with lung diseases. The pathogenic effects are related to the dimension, biopersistence and chemical composition of the fibres. In addition to the major mineral elements, mineral fibres contain trace elements and their content may play a role in fibre toxicity. To shed light on the role of trace elements in asbestos carcinogenesis, knowledge on their concentration in asbestos-mineral fibres is mandatory. It is possible that trace elements play a synergetic factor in the pathogenesis of diseases caused by the inhalation of mineral fibres. In this paper, the concentration levels of trace elements from three chrysotile samples, four amphibole asbestos samples (UICC amosite, UICC anthophyllite, UICC crocidolite and tremolite) and fibrous erionite from Jersey, Nevada (USA) were determined using inductively coupled plasma mass spectrometry (ICP-MS). For all samples, the following trace elements were measured: Li, Be, Sc, V, Cr, Mn, Co, Ni, Cu, Zn, As, Rb, Sr, Y, Sb, Cs, Ba, La, Pb, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Th, U. Their distribution in the various mineral species is thoroughly discussed. The obtained results indicate that the amount of trace metals such as Mn, Cr, Co, Ni, Cu and Zn is higher in anthophyllite and chrysotile samples, whereas the amount of rare earth elements (REE) is higher in erionite and tremolite samples. The results of this work can be useful to the pathologists and biochemists who use asbestos minerals and fibrous erionite in-vitro studies as positive cyto- and geno-toxic standard references. Copyright © 2016 Elsevier Ltd. All rights reserved.

Comparative uptake of trace elements in vines and olive trees over calcareous soils in western La Mancha

NASA Astrophysics Data System (ADS)

Ángel Amorós, José; Higueras, Pablo; Pérez-de-los-Reyes, Caridad; Jesús García, Francisco; Villaseñor, Begoña; Bravo, Sandra; Losilla, María Luisa; María Moreno, Marta

2014-05-01

Grapevine (Vitis vinifera L.) and olive-tree (Olea europea L.) are very important cultures in Castilla-La Mancha for its extension and contribution to the regional economy. This study was carried out in the municipality of Carrión de Calatrava (Ciudad Real) where the variability of soils of different geological origin, with different evolutions giving a great diversity of soils. The metabolism of trace elements in plants has been extensively studied although each soil-plant system must be investigated, especially since small variations in composition can lead to marked differences. It can be stated that the composition of the plant reflects the environment where it is cultivated and the products of the plant (leaves, fruits, juices, etc…) will be influenced by the composition of the soil. The main aim of the work was to compare the uptake of 24 trace elements in grapevine and olive-tree cultivated in the same soil. Samples from surface soils and plant material (leaf) have been analyzed by X-ray fluorescence, obtaining trace elements in mg/kg. It can be concluded that the leaves of grapevines in the studied plots have shown content in elements: -Similar to the olive-tree in case of: Co, Ga, Y, Ta, Th, U y Nd. -Over to the olive-tree in: Sc, V, Cr, Ni, Rb, Sr, Zr, Nb, Ba, La, Ce, Hf y W. -Below to the olive-tree in: Cu, Zn, Cs y Pb. Keywords: woody culture soils, mineral nutrition, X-ray fluorescence.

Drinking water quality in the Ethiopian section of the East African Rift Valley I--data and health aspects.

PubMed

Reimann, Clemens; Bjorvatn, Kjell; Frengstad, Bjørn; Melaku, Zenebe; Tekle-Haimanot, Redda; Siewers, Ulrich

2003-07-20

Drinking water samples were collected throughout the Ethiopian part of the Rift Valley, separated into water drawn from deep wells (deeper than 60 m), shallow wells (<60 m deep), hot springs (T>36 degrees C), springs (T<32 degrees C) and rivers. A total of 138 samples were analysed for 70 parameters (Ag, Al, As, B, Ba, Be, Bi, Br, Ca, Cd, Ce, Cl, Co, Cr, Cs, Cu, Dy, Er, Eu, F, Fe, Ga, Gd, Ge, Hf, Hg, Ho, I, In, K, La, Li, Lu, Mg, Mn, Mo, Na, Nb, Nd, Ni, NO(2), NO(3), Pb, Pr, Rb, Sb, Se, Si, Sm, Sn, SO(4), Sr, Ta, Tb, Te, Th, Ti, Tl, Tm, U, V, W, Y, Yb, Zn, Zr, temperature, pH, conductivity and alkalinity) with ion chromatography (anions), spectrometry (ICP-OES and ICP-MS, cations) and parameter-specific (e.g. titration) techniques. In terms of European water directives and WHO guidelines, 86% of all wells yield water that fails to pass the quality standards set for drinking water. The most problematic element is fluoride (F), for which 33% of all samples returned values above 1.5 mg/l and up to 11.6 mg/l. The incidence of dental and skeletal fluorosis is well documented in the Rift Valley. Another problematic element may be uranium (U)-47% of all wells yield water with concentrations above the newly suggested WHO maximum acceptable concentration (MAC) of 2 microg/l. Fortunately, only 7% of the collected samples are above the 10 microg/l EU-MAC for As in drinking water.

Sodium Fluxes through Nonselective Cation Channels in the Plasma Membrane of Protoplasts from Arabidopsis Roots1

PubMed Central

Demidchik, Vadim; Tester, Mark

2002-01-01

The aim of the present work was to characterize Na+ currents through nonselective cation channels (NSCCs) in protoplasts derived from root cells of Arabidopsis. The procedure of the protoplast isolation was modified to increase the stability of Arabidopsis root protoplasts in low external Ca2+ by digesting tissue in elevated Ca2+. Experiments in whole-cell and outside-out modes were carried out. We found that Na+ currents in Arabidopsis root protoplasts were mediated by cation channels that were insensitive to externally applied tetraethylammonium+ and verapamil, had no time-dependent activation (permanently opened or completely activated within 1–2 ms), were voltage independent, and were weakly selective for monovalent cations. The selectivity sequence was as follows: K+ (1.49) > NH4+ (1.24) > Rb+ (1.15) ≈ Cs+ (1.10) ≈ Na+ (1.00) > Li+ (0.73) > tetraethylammonium+ (0.47). Arabidopsis root NSCCs were blocked by H+ (pK ≈ 6.0), Ca2+ (K1/2 ≈ 0.1 mm), Ba2+, Zn2+, La3+, Gd3+, quinine, and the His modifier diethylpyrocarbonate. They were insensitive to most organic blockers (nifedipine, verapamil, flufenamate, and amiloride) and to the SH-group modifier p-chloromercuriphenyl sulfonic acid. Voltage-insensitive, Ca2+-sensitive single channels were also resolved. Properties of Arabidopsis root NSCCs are discussed and compared with characteristics of similar conductances studied previously in plants and animals. It is suggested that NSCCs present a distinct group of plant ion channels, mediating toxic Na+ influx to the cell and probably having other important roles in physiological processes of plants. PMID:11842142

The permeability of endplate channels to monovalent and divalent metal cations

PubMed Central

1980-01-01

The relative permeability of endplate channels to monovalent and divalent metal ions was determined from reversal potentials. Thallium is the most permeant ion with a permeability ratio relative to Na+ of 2.5. The selectivity among alkali metals is weak with a sequence, Cs+ greater than Rb+ greater than K+ greater than Na+ greater than Li+, and permeability ratios of 1.4, 1.3, 1.1, 1.0, and 0.9. The selectivity among divalent ions is also weak, with a sequence for alkaline earths of Mg++ greater than Ca++ greater than Ba++ greater than Sr++. The transition metal ions Mn++, Co++, Ni++, Zn++, and Cd++ are also permeant. Permeability ratios for divalent ions decreased as the concentration of divalent ion was increased in a manner consistent with the negative surface potential theory of Lewis (1979 J. Physiol. (Lond.). 286: 417--445). With 20 mM XCl2 and 85.5 mM glucosamine.HCl in the external solution, the apparent permeability ratios for the alkaline earth cations (X++) are in the range 0.18--0.25. Alkali metal ions see the endplate channel as a water-filled, neutral pore without high-field-strength sites inside. Their permeability sequence is the same as their aqueous mobility sequence. Divalent ions, however, have a permeability sequence almost opposite from their mobility sequence and must experience some interaction with groups in the channel. In addition, the concentrations of monovalent and divalent ions are increased near the channel mouth by a weak negative surface potential. PMID:6247423

Fluid and chemical fluxes along a buried-basement ridge in the eastern Juan de Fuca Ridge flank

NASA Astrophysics Data System (ADS)

Hulme, S.; Wheat, C. G.

2010-12-01

Hydrothermal fluid circulation within oceanic crust at low temperatures affects global biogeochemical cycles, with the volume of fluid circulation rivaling that of the world’s water flux to the oceans from rivers. Our work focuses on the best studied low temperature hydrothermal system on the eastern flank of the Juan de Fuca Ridge where a buried basement ridge 100 km from the active spreading axis has been sampled with a variety of mediums. We use data from deep sea drilling, gravity coring, and submersible operations from five sites along-strike of the buried ridge to better constrain the chemical and fluid fluxes along this transect. A transport (advection-diffusion) model is applied to the data, constraining the volumetric fluid flux per unit length within the oceanic crust from 0.05 and 0.2 m3 y-1 cm-1 and identifying conservative elements within this system. Using an average fluid flux, reactive fluxes are determined for non-conservative elements within basaltic crust for twenty-four chemical species. Conservative species include K, Cl, SO4, Ba, Sr, Cs, Mo, and Y. Only Ca and the rare earth elements Ce and Gd are produced by basaltic basement. The remaining chemical species Mg, Na, ammonium, Li, Rb, Mn, Fe, Co, Zn, Cd, U, La and Yb are all consumed within upper basaltic basement. Fluxes of potentially-bioavailable redox species ammonium, Fe, and Mn into the upper basaltic basement are 3 to 20 nmol y-1cm-2. Possible mechanisms of removal are suggested, placing constraints on microbial metabolic activity and biomineralization.

Physico-chemistry and geochemistry of Balengou clay deposit (West Cameroon) with inference to an argillic hydrothermal alteration

NASA Astrophysics Data System (ADS)

Tassongwa, Bernard; Eba, François; Njoya, Dayirou; Tchakounté, Jacqueline Numbem; Jeudong, Narcisse; Nkoumbou, Charles; Njopwouo, Daniel

2017-09-01

Field description and sampling along two pits, granulometry, Atterberg limits, mineralogical (XRD, FTIR, DSC & TGA) and geochemical analyses of the Balengou clays help to determine their characteristics and the genesis of the deposit. The mineralogical composition is comprised of halloysite-kaolinite, quartz, montmorillonite, hematite, anatase, feldspar, zircon, chromite, and apatite. Gibbsite and illite occur at the shallow and deep depth, respectively. Dikes of sand-poor clays contain also cristobalite and tridymite. Pairs of elements Rb-Ba, Rb-Sr, Nb-Ta, Ta-Zr, TiO2-Zr display good positive correlations (R2 > 0.85). REE patterns are highly fractionated (LaN up to 3312, LaN/YbN: 19-10) and are marked by deep Ce and Eu negative anomalies. Immobile element canonical ratios indicate that the protoliths were commendite/pantelerite, rhyolite and dacite, or their plutonic equivalents. Mineralogical and geochemical features lead to the suggestion that the clays derived from an advanced argillic hydrothermal alteration.

β-decay properties in the Cs decay chain

NASA Astrophysics Data System (ADS)

Benzoni, G.; Lică, R.; Borge, M. J. G.; Fraile, L. M.; IDS Collaboration

2018-02-01

The study of the decay of neutron-rich Cs isotopes has two main objectives: on one side β decay is a perfect tool to access the low-spin structures in the daughter Ba nuclei, where the evolution of octupole deformed shapes can be followed, while, on the other hand, the study of the gross properties of these decays, in terms of decay rates and branching to delayed-neutron emission, are fundamental inputs for the modelling of the r-process in the Rare-Earth Elements peak. Results obtained at CERN-ISOLDE are discussed within this framework and compared to existing data and predictions from state-of-the-art nuclear models.

Trace elements transport in western Siberia rivers across a permafrost gradient

NASA Astrophysics Data System (ADS)

Pokrovsky, O. S.; Manasypov, R. M.; Loiko, S.; Krickov, I. A.; Kopysov, S. G.; Kolesnichenko, L. G.; Vorobyev, S. N.; Kirpotin, S. N.

2015-11-01

Towards a better understanding of trace element transport in permafrost-affected Earth surface environments, we sampled ∼ 60 large and small rivers (< 100 to ≤ 150 000 km2 watershed area) of Western Siberia Lowland (WSL) during spring flood and summer and winter base-flow across a 1500 km latitudinal gradient covering continuous, discontinuous, sporadic and permafrost-free zones. Analysis of ∼ 40 major and trace elements in dissolved (< 0.45 μm) fraction allowed establishing main environmental factors controlling the transport of metals and trace elements in rivers of this environmentally important region. No statistically significant effect of the basin size on most TE concentration was evidenced. Three category of trace elements were distinguished according to their concentration - latitude pattern: (i) increasing northward in spring and winter (Fe, Al, Ga (only winter), Ti (only winter), REEs, Pb, Zr, Hf, Th (only winter)), linked to leaching from peat and/or redox processes and transport in the form of Fe-rich colloids, (ii) decreasing northward during all seasons (Sr, Mo, U, As, Sb) marking the underground water influence of river feeding and (iii) elements without distinct trend from S to N whose variations within each latitude range were higher than the difference between latitudinal ranges (B, Li, Ti (except summer), Cr, V, Mn, Zn, Cd, Cs, Hf, Th). In addition to these general features, specific, northward increase during spring period was mostly pronounced for Fe, Mn, Co, Zn and Ba and may stem from a combination of enhanced leaching from the topsoil and vegetation and bottom waters of the lakes (spring overturn). A spring time northward decrease was observed for Ni, Cu, Zr, Rb. The southward increase in summer was strongly visible for Fe, Ni, Ba, Rb and V, probably due to peat/moss release (Ni, Ba, Rb) or groundwater feeding (Fe, V). The Principal Component Analysis demonstrated two main factors potentially controlling the ensemble of TE concentration variation. The first factor, responsible for 16-20 % of overall variation, included trivalent and tetravalent hydrolysates, Cr, V, and DOC and presumably reflected the presence of organo-mineral colloids, as also confirmed by previous studies in Siberian rivers. The 2nd factor (8-14 % variation) was linked to the latitude of the watershed and acted on elements affected by the groundwater feeding (DIC, Sr, Mo, As, Sb, U), whose concentration decreased significantly northward during all seasons. Overall, the rank of environmental factors on TE concentration in western Siberian rivers was latitude (3 permafrost zones) > season > watershed size. The effect of the latitude was minimal in spring for most TE but highly visible for Sr, Mo, Sb and U. The main factors controlling the shift of river feeding from surface and subsurface flow to deep underground flow in the permafrost-bearing zone were the depth of the active (unfrozen) seasonal layer and its position in organic or mineral horizons of the soil profile. In the permafrost-free zone, the relative role of carbonate mineral-bearing base rock feeding vs. bog water feeding determined the pattern of trace element concentration and fluxes in rivers of various size as a function of season. Comparison of obtained TE fluxes in WSL rivers with those of other subarctic rivers demonstrated reasonable agreement for most trace elements; the lithology of base rocks was the major factor controlling the magnitude of TE fluxes. The climate change in western Siberia and permafrost boundary migration will affect essentially the elements controlled by underground water feeding (DIC, alkaline-earth elements (Ca, Sr), oxyanions (Mo, Sb, As) and U). The thickening of the active layer may increase the export of trivalent and tetravalent hydrolysates in the form of organo-ferric colloids. Plant litter-originated divalent metals present as organic complexes may be retained via adsorption on mineral horizon. However, due to various counterbalanced processes controlling element source and sinks in plants - peat - mineral soil - river systems, the overall impact of the permafrost thaw on TE export from the land to the ocean may be smaller than that foreseen by merely active layer thickening and permafrost boundary shift.

Chemical Trends in Solid Alkali Pertechnetates.

PubMed

Weaver, Jamie; Soderquist, Chuck Z; Washton, Nancy M; Lipton, Andrew S; Gassman, Paul L; Lukens, Wayne W; Kruger, Albert A; Wall, Nathalie A; McCloy, John S

2017-03-06

Insight into the solid-state chemistry of pure technetium-99 ( 99 Tc) oxides is required in the development of a robust immobilization and disposal system for nuclear waste stemming from the radiopharmaceutical industry, from the production of nuclear weapons, and from spent nuclear fuel. However, because of its radiotoxicity and the subsequent requirement of special facilities and handling procedures for research, only a few studies have been completed, many of which are over 20 years old. In this study, we report the synthesis of pure alkali pertechnetates (sodium, potassium, rubidium, and cesium) and analysis of these compounds by Raman spectroscopy, X-ray absorption spectroscopy (XANES and EXAFS), solid-state nuclear magnetic resonance (static and magic angle spinning), and neutron diffraction. The structures and spectral signatures of these compounds will aid in refining the understanding of 99 Tc incorporation into and release from nuclear waste glasses. NaTcO 4 shows aspects of the relatively higher electronegativity of the Na atom, resulting in large distortions of the pertechnetate tetrahedron and deshielding of the 99 Tc nucleus relative to the aqueous TcO 4 - . At the other extreme, the large Cs and Rb atoms interact only weakly with the pertechnetate, have closer to perfect tetrahedral symmetry at the Tc atom, and have very similar vibrational spectra, even though the crystal structure of CsTcO 4 is orthorhombic while that of RbTcO 4 is tetragonal. Further trends are observed in the cell volume and quadrupolar coupling constant.

Chemical Trends in Solid Alkali Pertechnetates

DOE PAGES

Weaver, Jamie; Soderquist, Chuck Z.; Washton, Nancy M.; ...

2017-02-21

Insight into the solid-state chemistry of pure technetium-99 ( 99Tc) oxides is required in the development of a robust immobilization and disposal system for nuclear waste stemming from the radiopharmaceutical industry, from the production of nuclear weapons, and from spent nuclear fuel. However, because of its radiotoxicity and the subsequent requirement of special facilities and handling procedures for research, only a few studies have been completed, many of which are over 20 years old. In this study, we report the synthesis of pure alkali pertechnetates (sodium, potassium, rubidium, and cesium) and analysis of these compounds by Raman spectroscopy, X-ray absorptionmore » spectroscopy (XANES and EXAFS), solid-state nuclear magnetic resonance (static and magic angle spinning), and neutron diffraction. The structures and spectral signatures of these compounds will aid in refining the understanding of 99Tc incorporation into and release from nuclear waste glasses. NaTcO 4 shows aspects of the relatively higher electronegativity of the Na atom, resulting in large distortions of the pertechnetate tetrahedron and deshielding of the 99Tc nucleus relative to the aqueous TcO 4 –. At the other extreme, the large Cs and Rb atoms interact only weakly with the pertechnetate, have closer to perfect tetrahedral symmetry at the Tc atom, and have very similar vibrational spectra, even though the crystal structure of CsTcO 4 is orthorhombic while that of RbTcO 4 is tetragonal. Further trends are observed in the cell volume and quadrupolar coupling constant.« less

Conformational effects on cationization of poly(ethylene glycol) by alkali metal ions in matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

NASA Astrophysics Data System (ADS)

Shimada, Kayori; Matsuyama, Shigetomo; Saito, Takeshi; Kinugasa, Shinichi; Nagahata, Ritsuko; Kawabata, Shin-Ichirou

2005-12-01

Conformational effects of polymer chains on matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) were studied by using an equimolar mixture of uniform poly(ethylene glycol)s (PEGs) and by molecular dynamics simulations. Uniform PEGs with degrees of polymerization n = 8-39 were separated from commercial PEG samples by preparative supercritical fluid chromatography. MALDI-TOFMS spectra of an equimolar mixture of the uniform PEGs in aqueous ethanol were measured by adding a mixture of 2,5-dihydroxybenzoic acid (as a matrix reagent) and five alkali metal chlorides (LiCl, NaCl, KCl, RbCl, and CsCl). After optimization of the matrix concentration and laser power, five types of adduct cationized by Li+, Na+, K+, Rb+, and Cs+ could be identified simultaneously in the same spectrum. In the lower molecular-mass region around 103, the spectral intensity increase rapidly with increasing molecular mass of PEG; this rapid increase in the spectral intensity started at a lower molecular mass for smaller adduct cations. Molecular dynamics simulations were used to calculated the affinity of PEG for the adduct cations. These experimental and simulated results showed that the observed spectral intensities in MALDI-TOFMS were markedly affected by the species of adduct cations and the degree of polymerization of the PEG, and that they were dependent on the stability of the PEG-cation complex.

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

Weaver, Jamie; Soderquist, Chuck Z.; Washton, Nancy M.

Insight into the solid-state chemistry of pure technetium-99 ( 99Tc) oxides is required in the development of a robust immobilization and disposal system for nuclear waste stemming from the radiopharmaceutical industry, from the production of nuclear weapons, and from spent nuclear fuel. However, because of its radiotoxicity and the subsequent requirement of special facilities and handling procedures for research, only a few studies have been completed, many of which are over 20 years old. In this study, we report the synthesis of pure alkali pertechnetates (sodium, potassium, rubidium, and cesium) and analysis of these compounds by Raman spectroscopy, X-ray absorptionmore » spectroscopy (XANES and EXAFS), solid-state nuclear magnetic resonance (static and magic angle spinning), and neutron diffraction. The structures and spectral signatures of these compounds will aid in refining the understanding of 99Tc incorporation into and release from nuclear waste glasses. NaTcO 4 shows aspects of the relatively higher electronegativity of the Na atom, resulting in large distortions of the pertechnetate tetrahedron and deshielding of the 99Tc nucleus relative to the aqueous TcO 4 –. At the other extreme, the large Cs and Rb atoms interact only weakly with the pertechnetate, have closer to perfect tetrahedral symmetry at the Tc atom, and have very similar vibrational spectra, even though the crystal structure of CsTcO 4 is orthorhombic while that of RbTcO 4 is tetragonal. Further trends are observed in the cell volume and quadrupolar coupling constant.« less

Sticky ions in biological systems.

PubMed Central

Collins, K D

1995-01-01

Aqueous gel sieving chromatography on Sephadex G-10 of the Group IA cations (Li+, Na+, K+, Rb+, Cs+) plus NH4+ as the Cl- salts, in combination with previous results for the halide anions (F-, Cl-, Br-, I-) as the Na+ salts [Washabaugh, M.W. & Collins, K.D. (1986) J. Biol. Chem. 261, 12477-12485], leads to the following conclusions. (i) The small monovalent ions (Li+, Na+, F-) flow through the gel with water molecules attached, whereas the large monovalent ions (K+, Rb+, Cs+, Cl-, Br-, I-) adsorb to the nonpolar surface of the gel, a process requiring partial dehydration of the ion and implying that these ions bind the immediately adjacent water molecules weakly. (ii) The transition from strong to weak hydration occurs at a radius of about 1.78 A for the monovalent anions, compared with a radius of about 1.06 A for the monovalent cations (using ionic radii), indicating that the anions are more strongly hydrated than the cations for a given charge density. (iii) The anions show larger deviations from ideal behavior (an elution position corresponding to the anhydrous molecular weight) than do the cations and dominate the chromatographic behavior of the neutral salts. These results are interpreted to mean that weakly hydrated ions (chaotropes) are "pushed" onto weakly hydrated surfaces by strong water-water interactions and that the transition from strong ionic hydration to weak ionic hydration occurs where the strength of ion-water interactions approximately equals the strength of water-water interactions in bulk solution. PMID:7539920

Effect of Guest Atom Composition on the Structural and Vibrational Properties of the Type II Clathrate-Based Materials AxSi136, AxGe136 and AxSn136 (A = Na, K, Rb, Cs; 0 ≤ x ≤ 24).

PubMed

Xue, Dong; Myles, Charles W; Higgins, Craig

2016-08-11

Type II clathrates are interesting due to their potential thermoelectric applications. Powdered X-ray diffraction (XRD) data and density functional calculations for Na x Si 136 found a lattice contraction as x increases for 0 < x < 8 and an expansion as x increases for x > 8. This is explained by XRD data that shows that as x increases, the Si 28 cages are filled first for x < 8 and the Si 20 cages are then filled for x > 8. Motivated by this work, here we report the results of first-principles calculations of the structural and vibrational properties of the Type II clathrate compounds A x Si 136 , A x Ge 136 , and A x Sn 136 . We present results for the variation of the lattice constants, bulk moduli, and other structural parameters with x. These are contrasted for the Si, Ge, and Sn compounds and for guests A = Na, K, Rb, and Cs. We also present calculated results of phonon dispersion relations for Na₄Si 136 , Na₄Ge 136 , and Na₄Sn 136 and we compare these for the three materials. Finally, we present calculated results for the elastic constants in Na x Si 136 , Na x Ge 136 , and Na x Sn 136 for x = 4 and 8. These are compared for the three hosts, as well as for the two compositions.

Toward chemical accuracy in the description of ion-water interactions through many-body representations. Alkali-water dimer potential energy surfaces

NASA Astrophysics Data System (ADS)

Riera, Marc; Mardirossian, Narbe; Bajaj, Pushp; Götz, Andreas W.; Paesani, Francesco

2017-10-01

This study presents the extension of the MB-nrg (Many-Body energy) theoretical/computational framework of transferable potential energy functions (PEFs) for molecular simulations of alkali metal ion-water systems. The MB-nrg PEFs are built upon the many-body expansion of the total energy and include the explicit treatment of one-body, two-body, and three-body interactions, with all higher-order contributions described by classical induction. This study focuses on the MB-nrg two-body terms describing the full-dimensional potential energy surfaces of the M+(H2O) dimers, where M+ = Li+, Na+, K+, Rb+, and Cs+. The MB-nrg PEFs are derived entirely from "first principles" calculations carried out at the explicitly correlated coupled-cluster level including single, double, and perturbative triple excitations [CCSD(T)-F12b] for Li+ and Na+ and at the CCSD(T) level for K+, Rb+, and Cs+. The accuracy of the MB-nrg PEFs is systematically assessed through an extensive analysis of interaction energies, structures, and harmonic frequencies for all five M+(H2O) dimers. In all cases, the MB-nrg PEFs are shown to be superior to both polarizable force fields and ab initio models based on density functional theory. As previously demonstrated for halide-water dimers, the MB-nrg PEFs achieve higher accuracy by correctly describing short-range quantum-mechanical effects associated with electron density overlap as well as long-range electrostatic many-body interactions.

Determining baseline element composition of lichens. I. Parmelia sulcata at Theodore Roosevelt national park, North Dakota

USGS Publications Warehouse

Gough, L.P.; Severson, R.C.; Jackson, L.L.

1988-01-01

Element-concentration baselines are given for Parmelia sulcata and associated soils. Parmelia chlorochroa was found sporadically and therefore only representative concentration ranges are reported for this species. Element data include (1) for lichens; Al, As, Ba, B, Ca, Cr, Cu, Fe, Hg, Mn, Ni, P, Sr, S, Ti, V, Y, and Zn; and (2) for soils: Al, Ba, Be, Ca, Cs, Cr, Cu, Fe, Hg, Mg, Mn, Ni, Nb, P, Pb, Sr, S, Ti, V, Y, and Zn. Very little (usually 7.2 km); thus, P sulcata is, in general, chemically similar throughout the park. This same uniformity was found for soil geochemistry. Numerous samples collected at close intervals would be required, therefore, to produce detailed element-concentration maps for P. sulcata and soils. No instances of elemental phytotoxic conditions were found; however, P. sulcata apparently possesses large concentrations of Ba, Cu, Fe, Pb, S, V, and possibly Zn.

A new series of oxycarbonate superconductors (Cu(0.5)C(0.5))(m)Ba(m+1)Ca(n-1)Cu(n)O2(m+n)+1

NASA Technical Reports Server (NTRS)

Takayama-Muromachi, E.; Kawashima, T.; Matsui, Y.

1995-01-01

We found a new series of oxycarbonate superconductors in the Ba-CaCu-C-O system under high pressure of 5 GPa. Their ideal formula is (Cu(0.5)C(0.5)(m)Ba(m+1)Ca(n-1)Cu(n)O2)((m+n)+1) ((Cu,C)-m(m+1)(n-1)n). Thus far, n = 3, 4 members of the m = 1 series, (Cu,C)-1223 and (Cu,C)-1234, have been prepared in bulk while n = 4, 5 members, (Cu,C)-2334 and (Cu,C)-2345, have been prepared for the m = 2 series. (Cu,C)-1223 shows superconductivity below 67 K while T(sub c)'s of other compounds are above 110 K. In particular, (Cu,C)-1234 has the highest T(sub c) of 117 K.

Cold-Atom Clocks on Earth and in Space

NASA Astrophysics Data System (ADS)

Lemonde, Pierre; Laurent, Philippe; Santarelli, Giorgio; Abgrall, Michel; Sortais, Yvan; Bize, Sebastien; Nicolas, Christophe; Zhang, Shougang; Clairon, Andre; Dimarcq, Noel; Petit, Pierre; Mann, Antony G.; Luiten, Andre N.; Chang, Sheng; Salomon, Christophe

We present recent progress on microwave clocks that make use of laser-cooled atoms. With an ultra-stable cryogenic sapphire oscillator as interrogation oscillator, a cesium fountain operates at the quantum projection noise limit. With 6 x10^5 detected atoms, the relative frequency stability is 4 x10^-14 &1/2circ, where τ is the integration time in seconds. This stability is comparable to that of hydrogen masers. At τ=2 x10^4s, the measured stability reaches 6 x10^-16. A 87Rb fountain has also been constructed and the 87Rb ground-state hyperfine energy has been compared to the Cs primary standard with a relative accuracy of 2.5 x10^-15. The 87Rb collisional shift is found to be at least 30 times below that of cesium. We also describe a transportable cesium fountain, which will be used for frequency comparisons with an accuracy of 10-15 or below. Finally, we present the details of a space mission for a cesium standard which has been selected by the European Space Agency (ESA) to fly on the International Space Station in 2003.

Transfer of a weakly bound electron in collisions of Rydberg atoms with neutral particles. II. Ion-pair formation and resonant quenching of the Rb(nl) and Ne(nl) States by Ca, Sr, and Ba atoms

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

Narits, A. A.; Mironchuk, E. S.; Lebedev, V. S., E-mail: vlebedev@sci.lebedev.ru

2013-10-15

Electron-transfer processes are studied in thermal collisions of Rydberg atoms with alkaline-earth Ca(4s{sup 2}), Sr(5s{sup 2}), and Ba(6s{sup 2}) atoms capable of forming negative ions with a weakly bound outermost p-electron. We consider the ion-pair formation and resonant quenching of highly excited atomic states caused by transitions between Rydberg covalent and ionic terms of a quasi-molecule produced in collisions of particles. The contributions of these reaction channels to the total depopulation cross section of Rydberg states of Rb(nl) and Ne(nl) atoms as functions of the principal quantum number n are compared for selectively excited nl-levels with l Much-Less-Than n andmore » for states with large orbital quantum numbers l = n - 1, n - 2. It is shown that the contribution from resonant quenching dominates at small values of n, and the ion-pair formation process begins to dominate with increasing n. The values and positions of the maxima of cross sections for both processes strongly depend on the electron affinity of an alkaline-earth atom and on the orbital angular momentum l of a highly excited atom. It is shown that in the case of Rydberg atoms in states with large l {approx} n - 1, the rate constants of ion-pair formation and collisional quenching are considerably lower than those for nl-levels with l Much-Less-Than n.« less

Trace and Ultra-trace Elements in the Deepest Part of the Vostok Ice Core, Antarctica: Geochemical Characterization of the Sub-glacial Lake Environment

NASA Astrophysics Data System (ADS)

Turetta, C.; Planchon, F.; Gabrielli, P.; Cozzi, G.; Cairns, W.; Barbaro, E.; Petit, J. R.; Bulat, S.; Boutron, C.; Barbante, C.

2016-12-01

We present in this study comprehensive data on the occurrence of 25 trace and ultra-trace elements in the deepest part of the Vostok ice core. The determination of Li, Na, Mg, Al, K, Ca, V, Cr, Mn, Fe, Co, Cu, Zn, As, Se, Rb, Sr, Mo, Ag, Cd, Sb, Ba, Pb, Bi and U has been performed in the different types of ice encountered from 3271 m to 3609 m of depth, corresponding to atmospheric ice, glacial flour and to accreted ice originating from the freezing of Lake Vostok waters. From atmospheric ice and glacial flour, the relative contributions of primary aerosols were evaluated for each element using a chemical mass balance approach in order to provide a first order evaluation of their partition between soluble (sea-salt) and insoluble (wind-blown dust) fractions in the ice. Sea-salt spray aerosols are the main source of impurities to the ice for certain elements (Na, Mg and K levels, and in a lesser extent to Ca, Sr, Rb, Li and U) while for other elements (Al, V, Cr, Mn, Fe, Co, Cu, Zn, Mo, Sb, Ba and Pb as well as the non sea salt fractions of Mg, K, Ca, Sr, Rb, Li and U) dust inputs appear to primarily control their depositional variability. For the glacial flour, the comparable levels of elements with the overlying atmospheric ice suggest that incorporation of abrasion debris at the glacier is quite limited in the sections considered. For the accreted ice originating from the subglacial waters of Lake Vostok, we observed a major chemical shift in the composition of the ice showing two distinct trends that we assumed to be derived from the chemical speciation of elements. The study of the glacier ice and the glacial flour has allowed us to perform a detailed characterisation of elemental abundances related to the aerosol sources variability and also to illustrate the interaction between the ice-sheet and the bedrock.

Caractérisation pétrologique et géochimique du magmatisme ubendien du secteur de Pepa-Lubumba, sur le plateau des Marungu (Nord-Est du Shaba, Zaire). Signification géodynamique dans l'évolution de la chaîne ubendienne

NASA Astrophysics Data System (ADS)

Kabengele, M.; Lubala, R. T.; Cabanis, B.

Volcanic and plutonic rocks of Pepa-Lubumba area in the Marungu plateau (Zaire) are mainly represented by intermediate and acid members which contain low abundances in TiO 2 (0.3 - 1.3 wt%). All these rocks exhibit a high-K calc-alkaline affinity and belong to a calc-alkaline continental-margin series. The large proportion of frequently zoned (normal and reverse zoning) plagioclase, the presence of hydrous phases (tschermakitic and Mg-hornblende, Mg-biotite), the early crystallization of FeTi oxides indicate crystallization under high water pressure conditions, consistent with a calc-alkaline affinity. High abundances in K, Rb, Sr and Ba; lack of correlation between Rb and Ba, low values of Rb/Zr (0.5 - 0.9) in granitoids, high contents of LREE and HFSE (Th/Ta : 6 - 14), are characteristic of "Andinotype" magmas. A whole rock RbSr isochron gives an emplacement age for granitoids of 1861 ± 28 Ma (MSWD : 0.82), Sr initial ratio of 0.7026 and epsilon Sr i of + 4.7. PbPb isotopes systematics for the same rocks give the following ratio ranges : 206Pb/ 204Pb : 17.26 - 20.10; 207Pb/ 204Pb 15.52 - 15.85, 208Pb/ 204Pb : 37.2 - 41.80. The low Sr initial ratio indicates an upper mantle source; while the PBPb isotope ratios suggest that the mantellic liquids have been contaminated by crustal material en route to the upper levels. In the regional geologic context, this magmatism forms a part of an important plutovolcanic Ubendian (Early Proterozoic) complex which crops out in Western Tanzania, North-Eastern Zambia and Marungu plateau (Zaire) and contains two magmatic cycles which define a spatial and temporal zonation suggesting a geodynamic evolution model for the Ubendian belt comprising subduction-obduction-collision processes. This latter episode has been relayed by a relaxation phase marked by emplacement of a third tholeiitic basic plutonic cycle.

Electronic and structural ground state of heavy alkali metals at high pressure

DOE PAGES

Fabbris, G.; Lim, J.; Veiga, L. S. I.; ...

2015-02-17

Here, alkali metals display unexpected properties at high pressure, including emergence of low symmetry crystal structures, that appear to occur due to enhanced electronic correlations among the otherwise nearly-free conduction electrons. We investigate the high pressure electronic and structural ground state of K, Rb, and Cs using x-ray absorption spectroscopy and x-ray diffraction measurements together with ab initio theoretical calculations. The sequence of phase transitions under pressure observed at low temperature is similar in all three heavy alkalis except for the absence of the oC84 phase in Cs. Both the experimental and theoretical results point to pressure-enhanced localization of themore » valence electrons characterized by pseudo-gap formation near the Fermi level and strong spd hybridization. Although the crystal structures predicted to host magnetic order in K are not observed, the localization process appears to drive these alkalis closer to a strongly correlated electron state.« less

On the Effectiveness of Nature-Inspired Metaheuristic Algorithms for Performing Phase Equilibrium Thermodynamic Calculations

PubMed Central

Fateen, Seif-Eddeen K.; Bonilla-Petriciolet, Adrian

2014-01-01

The search for reliable and efficient global optimization algorithms for solving phase stability and phase equilibrium problems in applied thermodynamics is an ongoing area of research. In this study, we evaluated and compared the reliability and efficiency of eight selected nature-inspired metaheuristic algorithms for solving difficult phase stability and phase equilibrium problems. These algorithms are the cuckoo search (CS), intelligent firefly (IFA), bat (BA), artificial bee colony (ABC), MAKHA, a hybrid between monkey algorithm and krill herd algorithm, covariance matrix adaptation evolution strategy (CMAES), magnetic charged system search (MCSS), and bare bones particle swarm optimization (BBPSO). The results clearly showed that CS is the most reliable of all methods as it successfully solved all thermodynamic problems tested in this study. CS proved to be a promising nature-inspired optimization method to perform applied thermodynamic calculations for process design. PMID:24967430

On the effectiveness of nature-inspired metaheuristic algorithms for performing phase equilibrium thermodynamic calculations.

PubMed

Fateen, Seif-Eddeen K; Bonilla-Petriciolet, Adrian

2014-01-01

The search for reliable and efficient global optimization algorithms for solving phase stability and phase equilibrium problems in applied thermodynamics is an ongoing area of research. In this study, we evaluated and compared the reliability and efficiency of eight selected nature-inspired metaheuristic algorithms for solving difficult phase stability and phase equilibrium problems. These algorithms are the cuckoo search (CS), intelligent firefly (IFA), bat (BA), artificial bee colony (ABC), MAKHA, a hybrid between monkey algorithm and krill herd algorithm, covariance matrix adaptation evolution strategy (CMAES), magnetic charged system search (MCSS), and bare bones particle swarm optimization (BBPSO). The results clearly showed that CS is the most reliable of all methods as it successfully solved all thermodynamic problems tested in this study. CS proved to be a promising nature-inspired optimization method to perform applied thermodynamic calculations for process design.

The 22nd Annual Precise Time and Time Interval (PTTI) Applications and Planning Meeting

NASA Technical Reports Server (NTRS)

Sydnor, Richard L. (Editor)

1990-01-01

Papers presented at the 22nd Annual Precise Time and Time Interval (PTTI) Applications and Planning Meeting are compiled. The following subject areas are covered: Rb, Cs, and H-based frequency standards and cryogenic and trapped-ion technology; satellite laser tracking networks, GLONASS timing, intercomparison of national time scales and international telecommunications; telecommunications, power distribution, platform positioning, and geophysical survey industries; military communications and navigation systems; and dissemination of precise time and frequency by means of GPS, GLONASS, MILSTAR, LORAN, and synchronous communication satellites.

Size distribution of radioactive particles collected at Tokai, Japan 6 days after the nuclear accident.

PubMed

Miyamoto, Yutaka; Yasuda, Kenichiro; Magara, Masaaki

2014-06-01

Airborne radioactive particles released by the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident in 2011 were collected with a cascade low-pressure impactor at the Japan Atomic Energy Agency (JAEA) in Tokai, Japan, 114 km south of the FDNPP. Size-fractionated samples were collected twice, in the periods of March 17-April 1, 2011, and May 9-13, 2011. These size-fractionated samplings were carried out in the earliest days at a short distance from the FDNPP. Radioactivity of short-lived nuclides (several ten days of half-life) was determined as well as (134)Cs and (137)Cs. The elemental composition of size-fractionated samples was also measured. In the first collection, the activity median aerodynamic diameter (AMAD) of (129m)Te, (140)Ba, (134)Cs, (136)Cs and (137)Cs was 1.5-1.6 μm, while the diameter of (131)I was 0.45 μm. The diameters of (134)Cs and (137)Cs in the second collection were expressed as three peaks at <0.5 μm, 0.94 μm, and 7.8 μm. The (134)Cs/(137)Cs ratio of the first collection was 1.02 in total, but the ratio in the fine fractions was 0.91. A distribution map of (134)Cs/(137)Cs - (136)Cs/(137)Cs ratios was helpful in understanding the change of radioactive Cs composition. The Cs composition of size fractions <0.43 μm and the composition in the 1.1-2.1 μm range (including the AMAD of 1.5-1.6 μm) were similar to the calculated compositions of fuels in the reactors No. 1 and No. 3 at the FDNPP using the ORIGEN-II code. The Cs composition collected in May, 2011 was similar to the calculation results of reactor No. 2 fuel composition. The change of Cs composition implies that the radioactive Cs was released from the three reactors at the FDNPP via different processes. Copyright © 2014 Elsevier Ltd. All rights reserved.

Rubidium atomic frequency standards for GPS Block IIR

NASA Technical Reports Server (NTRS)

Riley, William J.

1990-01-01

The Rubidium Atomic Frequency Standards (RAFS) were provided for the GPS Block IIR NAVSTAR satellites. These satellites will replenish and upgrade the space segment of the Global Positioning System in the mid 1990s. The GPS RAFS Rb clocks are the latest generation of the high-performance rubidium frequency standards. They offer an aging rate in the low pp 10(exp 14)/day range and a drift-corrected 1-day stability in the low pp 10(exp 14) range. The Block IIR version of these devices will have improved performance, higher reliability, smaller size, and greater radiation hardness. The GPS Block IIR atomic clocks have a natural frequency configuration whereby they output a frequency of about 13.4 MHz that is a submultiple of the atomic resonance of Rb (or Cs). The RAFS operates at a low, fixed C-field for increased stability. The GPS Block IIR RAFS design, including the changes and improvements made, and the test results obtained are described.

Exploratory Solid-State Synthesis of Uranium Chalcogenides and Mixed Anion Uranium Chalcogenides

NASA Astrophysics Data System (ADS)

Ward, Matthew David

Several uranium chalcogenides and mixed anion uranium chalcogenides have been synthesized by solid-state synthetic methods. Structural determinations were carried out via single-crystal X-ray diffraction. Some of these compounds have been further characterized by magnetic measurements, optical properties measurements, Raman spectroscopy, resistivity measurements, XANES and XPS. Eight compounds of the composition MU8Q17 were synthesized and characterized by single-crystal X-ray diffraction. All of these compounds crystallize in the CrU8S17 structure type. XANES measurements indicate that ScU8S17 contains Sc3+ and must be charge balanced with some amount of U 3+. Two compounds of the composition ATiU3Te9 crystallize as black rectangular plates. From single-crystal magnetic measurements, CsTiU 3Te9 is consistent with antiferromagnetic coupling between magnetic U atoms. The uranium chalcogenide compounds NiUS3 and Cr4US 8 were synthesized from reaction of the elements in various fluxes. NiUS3 crystallizes in the GdFeO3 structure type. Cr 4US8 crystallizes in the orthorhombic space group D - Pnma and its structure is related to that of Li4UF 8. The compounds Rh2U6S15, Cs 2Ti2U6Se15, and Cs2Cr 2U6Se15 crystallize as black prisms in the cubic space group O-Im3m. Magnetic measurements on Cs 2Cr2U6Se15 give a value for the Weiss temperature, θWeiss, of 57.59 K, indicative of ferromagnetic coupling. Black plates of CsScU(Se2)Se3 were synthesized from the reaction of the elements in a CsCl flux. CsScU(Se2)Se 3 crystallizes in the orthorhombic space group D- Cmcm . Magnetic susceptibility measurements on CsScU(Se2)Se 3 indicate three regions of magnetic response. The uranium double salt Cs5[U2(μ-S 2)2Cl8]I crystallizes as red plates. Cs 5[U2(μ-S2)2Cl 8]I displays optical anisotropy with band gap energies of 1.99 eV and 2.08 eV along the [001] and [100] polarizations. The uranium oxychalcogenides U7O2Se12 and Na2Ba2(UO2)S4 were synthesized by intentional oxygen contamination. The structure of U7O 2Se12 is related to the previously reported U7Q 12. Na2Ba2(UO2)S4 contains isolated uranyl polyhedra in which each uranium atom may be assigned an oxidation state of +6. The four uranium(IV) chlorophosphates, UCl4(POCl3), [U2Cl9][PCl4], UCl3(PO2Cl 2), and U2Cl8(POCl3) were synthesized in an effort to synthesize new novel uranyl sulfides. All are unstable, but UCl4(POCl3) is the thermodynamically favorable phase.

Localization of activities in the human body with a whole-body counter.

PubMed

Fischer, H; Schlagbauer, M

2007-01-01

The whole-body counter of the Radiation Protection Unit at the ARC Seibersdorf research GmbH has two HP Ge-detectors for measuring radionuclides, which are internally deposited in the human body. The detector system has a scanning geometry, where one detector is placed below the bed and the other detector above the bed. The body counter is placed in a massive shielded chamber. This device is especially used for measuring radioactive exposed workers with the possibility of intake by inhalation and ingestion. In the most cases whole-body counters are calibrated with anthropomorphic phantoms where activity is homogenously distributed. However, in some cases radioactivity can be located as a 'Hot Spot' in an organ. The localisation of 'Hot spots' at least in one dimension was the topic of this work. Experiments were done by means of a water-filled bottle phantom where three point sources (137Cs, 133Ba and 60Co) were placed at different positions. Measurements show that these radionuclides can be located within 1.5 cm along the longitudinal axis of the phantom with activities for 137Cs of at least 240 Bq, 133Ba of at least 670 Bq and 60Co of at least 140 Bq.

Muscarinic ACh Receptors Contribute to Aversive Olfactory Learning in Drosophila.

PubMed

Silva, Bryon; Molina-Fernández, Claudia; Ugalde, María Beatriz; Tognarelli, Eduardo I; Angel, Cristian; Campusano, Jorge M

2015-01-01

The most studied form of associative learning in Drosophila consists in pairing an odorant, the conditioned stimulus (CS), with an unconditioned stimulus (US). The timely arrival of the CS and US information to a specific Drosophila brain association region, the mushroom bodies (MB), can induce new olfactory memories. Thus, the MB is considered a coincidence detector. It has been shown that olfactory information is conveyed to the MB through cholinergic inputs that activate acetylcholine (ACh) receptors, while the US is encoded by biogenic amine (BA) systems. In recent years, we have advanced our understanding on the specific neural BA pathways and receptors involved in olfactory learning and memory. However, little information exists on the contribution of cholinergic receptors to this process. Here we evaluate for the first time the proposition that, as in mammals, muscarinic ACh receptors (mAChRs) contribute to memory formation in Drosophila. Our results show that pharmacological and genetic blockade of mAChRs in MB disrupts olfactory aversive memory in larvae. This effect is not explained by an alteration in the ability of animals to respond to odorants or to execute motor programs. These results show that mAChRs in MB contribute to generating olfactory memories in Drosophila.

Transmittance of optical materials from 0.17 micro to 3.0 micro.

PubMed

McCarthy, D E

1967-11-01

The transmittance of thirty-one optical materials is given from 0.17, micro to 3.0 micro. Included are NaCl, KBr, CsBr, CsI, CaF(2), BaF(2), NaF, TlBr, TICL, KRS-5, KRS-6, T-12, KC, CuC, T O(2), ADP, KDP, SrTiO(3), GaP, CaCO(3), CdSe, As(2)S(3), ruby, Al(2)O(3), Irtran 1-6, and quartz. All are synthetic with the exception of CaCO(3). In many cases, the short wavelength cutoff of the synthetic materials is less than that which has been reported for naturally occurring materials.

Absorption and backscatter of internal conversion electrons in the measurements of surface contamination of ¹³⁷Cs.

PubMed

Yunoki, A; Kawada, Y; Yamada, T; Unno, Y; Sato, Y; Hino, Y

2013-11-01

We measured 4π and 2π counting efficiencies for internal conversion electrons (ICEs), gross β-particles and also β-rays alone with various source conditions regarding absorber and backing foil thickness using e-X coincidence technique. Dominant differences regarding the penetration, attenuation and backscattering properties among ICEs and β-rays were revealed. Although the abundance of internal conversion electrons of (137)Cs-(137)Ba is only 9.35%, 60% of gross counts may be attributed to ICEs in worse source conditions. This information will be useful for radionuclide metrology and for surface contamination monitoring. © 2013 Elsevier Ltd. All rights reserved.

Apparent intermediate K conductance channel hyposmotic activation in human lens epithelial cells.

PubMed

Lauf, Peter K; Misri, Sandeep; Chimote, Ameet A; Adragna, Norma C

2008-03-01

This study explores the nature of K fluxes in human lens epithelial cells (LECs) in hyposmotic solutions. Total ion fluxes, Na-K pump, Cl-dependent Na-K-2Cl (NKCC), K-Cl (KCC) cotransport, and K channels were determined by 85Rb uptake and cell K (Kc) by atomic absorption spectrophotometry, and cell water gravimetrically after exposure to ouabain +/- bumetanide (Na-K pump and NKCC inhibitors), and ion channel inhibitors in varying osmolalities with Na, K, or methyl-d-glucamine and Cl, sulfamate, or nitrate. Reverse transcriptase polymerase chain reaction (RT-PCR), Western blot analyses, and immunochemistry were also performed. In isosmotic (300 mosM) media approximately 90% of the total Rb influx occurred through the Na-K pump and NKCC and approximately 10% through KCC and a residual leak. Hyposmotic media (150 mosM) decreased K(c) by a 16-fold higher K permeability and cell water, but failed to inactivate NKCC and activate KCC. Sucrose replacement or extracellular K to >57 mM, but not Rb or Cs, in hyposmotic media prevented Kc and water loss. Rb influx equaled Kc loss, both blocked by clotrimazole (IC50 approximately 25 microM) and partially by 1-[(2-chlorophenyl) diphenylmethyl]-1H-pyrazole (TRAM-34) inhibitors of the IK channel KCa3.1 but not by other K channel or connexin hemichannel blockers. Of several anion channel blockers (dihydro-indenyl)oxy]alkanoic acid (DIOA), 4-2(butyl-6,7-dichloro-2-cyclopentylindan-1-on-5-yl)oxybutyric acid (DCPIB), and phloretin totally or partially inhibited Kc loss and Rb influx, respectively. RT-PCR and immunochemistry confirmed the presence of KCa3.1 channels, aside of the KCC1, KCC2, KCC3 and KCC4 isoforms. Apparently, IK channels, possibly in parallel with volume-sensitive outwardly rectifying Cl channels, effect regulatory volume decrease in LECs.

Determination of zircon/melt trace element partition coefficients from SIMS analysis of melt inclusions in zircon

NASA Astrophysics Data System (ADS)

Thomas, J. B.; Bodnar, R. J.; Shimizu, N.; Sinha, A. K.

2002-09-01

Partition coefficients ( zircon/meltD M) for rare earth elements (REE) (La, Ce, Nd, Sm, Dy, Er and Yb) and other trace elements (Ba, Rb, B, Sr, Ti, Y and Nb) between zircon and melt have been calculated from secondary ion mass spectrometric (SIMS) analyses of zircon/melt inclusion pairs. The melt inclusion-mineral (MIM) technique shows that D REE increase in compatibility with increasing atomic number, similar to results of previous studies. However, D REE determined using the MIM technique are, in general, lower than previously reported values. Calculated D REE indicate that light REE with atomic numbers less than Sm are incompatible in zircon and become more incompatible with decreasing atomic number. This behavior is in contrast to most previously published results which indicate D > 1 and define a flat partitioning pattern for elements from La through Sm. The partition coefficients for the heavy REE determined using the MIM technique are lower than previously published results by factors of ≈15 to 20 but follow a similar trend. These differences are thought to reflect the effects of mineral and/or glass contaminants in samples from earlier studies which employed bulk analysis techniques. D REE determined using the MIM technique agree well with values predicted using the equations of Brice (1975), which are based on the size and elasticity of crystallographic sites. The presence of Ce 4+ in the melt results in elevated D Ce compared to neighboring REE due to the similar valence and size of Ce 4+ and Zr 4+. Predicted zircon/meltD values for Ce 4+ and Ce 3+ indicate that the Ce 4+/Ce 3+ ratios of the melt ranged from about 10 -3 to 10 -2. Partition coefficients for other trace elements determined in this study increase in compatibility in the order Ba < Rb < B < Sr < Ti < Y < Nb, with Ba, Rb, B and Sr showing incompatible behavior (D M < 1.0), and Ti, Y and Nb showing compatible behavior (D M > 1.0). The effect of partition coefficients on melt evolution during petrogenetic modeling was examined using partition coefficients determined in this study and compared to trends obtained using published partition coefficients. The lower D REE determined in this study result in smaller REE bulk distribution coefficients, for a given mineral assemblage, compared to those calculated using previously reported values. As an example, fractional crystallization of an assemblage composed of 35% hornblende, 64.5% plagioclase and 0.5% zircon produces a melt that becomes increasingly more enriched in Yb using the D Yb from this study. Using D Yb from Fujimaki (1986) results in a melt that becomes progressively depleted in Yb during crystallization.

The Odd Isotope Fractions of Barium in the Strongly r-process-enhanced (r-II) Stars

NASA Astrophysics Data System (ADS)

Wenyuan, Cui; Xiaohua, Jiang; Jianrong, Shi; Gang, Zhao; Bo, Zhang

2018-02-01

We determined the f odd,Ba values, 0.46 ± 0.08, 0.51 ± 0.09, 0.50 ± 0.13, and 0.48 ± 0.12, that correspond to the r-contribution 100% for four r-II stars, CS 29491-069, HE 1219-0312, HE 2327-5642, and HE 2252-4225, respectively. Our results suggest that almost all of the heavy elements (in the range from Ba to Pb) in r-II stars have a common origin, that is, from a single r-process (the main r-process). We found that the f odd,Ba has an intrinsic nature, and should keep a constant value of about 0.46 in the main r-process yields, which is responsible for the heavy element enhancement of r-II stars and of our Galaxy chemical enhancement. In addition, except for the abundance ratio [Ba/Eu] the f odd,Ba is also an important indicator, which can be used to study the relative contributions of the r- and s-processes during the chemical evolution history of the Milky Way and the enhancement mechanism in stars with peculiar abundances of heavy elements. Based on observations carried out at the European Southern Observatory, Paranal, Chile (Proposal number 170.D-0010 and 280.D-5011).

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

Berastegui, P.; Hull, S., E-mail: stephen.hull@stfc.ac.u; Eriksson, S.G.

The compound CsSn{sub 2}F{sub 5} has been investigated over the temperature range from ambient to 545 K using differential scanning calorimetry, impedance spectroscopy and neutron powder diffraction methods. A first-order phase transition is observed from DSC measurements at 510(2) K, to a phase possessing a high ionic conductivity ({sigma}{approx}2.5x10{sup -2} {Omega}{sup -1} cm{sup -1} at 520 K). The crystal structure of the high temperature superionic phase (labelled {alpha}) has been determined to be tetragonal (space group I4/mmm, a=4.2606(10) A, c=19.739(5) A and Z=2) in which the cations form layers perpendicular to the [001] direction, with a stacking sequence CsSnSnCsSnSn... Allmore » the anions are located in two partially occupied sites in the gap between the Cs and Sn layers, whilst the space between the Sn cations is empty, due to the orientation of the lone-pair electrons associated with the Sn{sup 2+}. The structure of {alpha}-CsSn{sub 2}F{sub 5} is discussed in relation to two other layered F{sup -} conducting superionic phases containing Sn{sup 2+} cations, {alpha}-RbSn{sub 2}F{sub 5} and {alpha}-PbSnF{sub 4} and, to facilitate this comparison, an improved structural characterisation of the former is also presented. The wider issue of the role of lone-pair cations such as Sn{sup 2+} in promoting dynamic disorder within an anion substructure is also briefly addressed. - Graphical abstract: CsSn{sub 2}F{sub 5} is shown to undergo a first order phase transition at 510(2) K to a superionic phase in which the specific electronic configuration of the Sn{sup 2+} plays a key role in promoting extensive disorder of the anions.« less

High-pressure behaviour of Cs{sub 2}V{sub 3}O{sub 8} fresnoite

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

Grzechnik, Andrzej, E-mail: grzechnik@xtal.rwth-aachen.de; Yeon, Jeongho; Zur Loye, Hans-Conrad

2016-06-15

Crystal structure of Cs{sub 2}V{sub 3}O{sub 8} fresnoite (P4bm, Z=2) has been studied using single-crystal X-ray diffraction in a diamond anvil cell to 8.6 GPa at room temperature. Cs{sub 2}V{sub 3}O{sub 8} undergoes a reversible first-order phase transition at about 4 GPa associated with anomalies in the pressure dependencies of the lattice parameters and unit-cell volume but without any symmetry change. Both structures consist of layers of corner-sharing V{sup 5+}O{sub 4} tetrahedra and V{sup 4+}O{sub 5} tetragonal pyramids separated by the Cs{sup +} cations located between the layers. At low pressures, the compression has little effect on the polarity ofmore » the structure. Above 4 GPa, the pseudosymmetry with respect to the corresponding centrosymmetric space group P4/mbm abruptly increases. The effects of external pressure and of the A{sup +} cation substitution in the vanadate fresnoites A{sub 2}V{sub 3}O{sub 8} (A{sup +}: K{sup +}, Rb{sup +}, NH{sub 4}{sup +}, Cs{sup +}) are discussed. - Graphical abstract: Non-centrosymmetric Cs{sub 2}V{sub 3}O{sub 8} undergoes a reversible first-order phase transition at about 4 GPa associated with an abrupt change of the pseudosymmetry with respect to the centrosymmetric space group P4/mbm. Display Omitted - Highlights: • High-pressure behaviour of vanadate fresnoites depends on alkali metal cations. • The size of the alkali metal cation determines whether the high-pressure phase is centrosymmetric. • No incommensurate structures are observed upon compression.« less

The new barium zinc mercurides Ba3ZnHg10 and BaZn0.6Hg3.4 - Synthesis, crystal and electronic structure

NASA Astrophysics Data System (ADS)

Schwarz, Michael; Wendorff, Marco; Röhr, Caroline

2012-12-01

The title compounds Ba3ZnHg10 and BaZn0.6Hg3.4 were synthesized from stoichiometric ratios of the elements in Ta crucibles. Their crystal structures, which both represent new structure types, have been determined using single crystal X-ray data. The structure of Ba3ZnHg10 (orthorhombic, oP28, space group Pmmn, a=701.2(3), b=1706.9(8), c=627.3(3)pm, Z=2, R1=0.0657) contains folded 44 Hg nets, where the meshes form the bases of flat rectangular pyramids resembling the structure of BaAl4. The flat pyramids are connected via Hg-Zn/Hg bonds, leaving large channels at the folds, in which Ba(1) and Hg(2) atoms alternate. Whereas the remaining Hg/Zn atoms form a covalent 3D network of three- to five-bonded atoms with short M-M distances (273-301 pm; CN 9-11), the Hg(2) atoms in the channels adopt a comparatively large coordination number of 12 and increased distances (317-348 pm) to their Zn/Hg neighbours. In the structure of BaZn0.6Hg3.4 (cubic, cI320, space group I4bar3d, a=2025.50(7) pm, Z=64, R1=0.0440), with a chemical composition not much different from that of Ba3ZnHg10, the Zn/Hg atoms of the mixed positions M(1/2) are arranged in an slightly distorted primitive cubic lattice with a 4×4×4 subcell relation to the unit cell. The 24 of the originating 64 cubes contain planar cis tetramers Hg(5,6)4 with Hg in a nearly trigonal planar or tetrahedral coordination. In another 24 of the small cubes, two opposing faces are decorated by Hg(3,4)2 dumbbells, two by Ba(2) atoms respectively. The third type of small cubes are centered by Ba(1) atoms only. The complex 3D polyanionic Hg/Zn network thus formed is compared with the Hg partial structure in Rb3Hg20 applying a group-subgroup relation. Despite their different overall structures, the connectivity of the negatively charged Hg atoms, the rather metallic Zn bonding characteristic (as obtained from FP-LAPW band structure calculations) and the coordination number of 16 for all Ba cations relate the two title compounds.

Ionomic profiling of Nicotiana langsdorffii wild-type and mutant genotypes exposed to abiotic stresses.

PubMed

Ardini, Francisco; Soggia, Francesco; Abelmoschi, Maria Luisa; Magi, Emanuele; Grotti, Marco

2013-01-01

To provide a new insight into the response of plants to abiotic stresses, the ionomic profiles of Nicotiana langsdorffii specimens have been determined before and after exposure to toxic metals (chromium) or drought conditions. The plants were genetically transformed with the rat glucocorticoid receptor (GR) or the gene for Agrobacterium rhizogenes rolC, because these modifications are known to produce an imbalance in phytohormone equilibria and a significant change in the defence response of the plant. Elemental profiles were obtained by developing and applying analytical procedures based on inductively coupled plasma atomic emission and mass spectrometry (ICP-AES/MS). In particular, the removal of isobaric interferences affecting the determination of Cr and V by ICP-MS was accomplished by use of a dynamic reaction cell, after optimization of the relevant conditions. The combined use of ICP atomic emission and mass spectrometry enabled the determination of 29 major and trace elements (Ba, Bi, Ca, Cd, Co, Cr, Cu, Eu, Fe, Ga, K, Li, Mg, Mn, Mo, Na, P, Pb, Pt, Rb, S, Sb, Sn, Sr, Te, V, W, Y, and Zn) in different parts of the plants (roots, stems, and leaves), with high accuracy and precision. Multivariate data processing and study of element distribution patterns provided new information about the ionomic response of the target organism to chemical treatment or water stress. Genetic modification mainly affected the distribution of Bi, Cr, Mo, Na, and S, indicating that these elements were involved in biochemical processes controlled by the GR or rolC genes. Chemical stress strongly affected accumulation of several elements (Ba, Ca, Fe, Ga, K, Li, Mn, Mo, Na, P, Pb, Rb, S, Sn, Te, V, and Zn) in different ways; for Ca, Fe, K, Mn, Na, and P the effect was quite similar to that observed in other studies after treatment with other transition elements, for example Cu and Cd. The effect of water deficit was less evident, mainly consisting in a decrease of Ba, Cr, Na, and Sr in roots.