What is strange about high-temperature superconductivity in cuprates?

NASA Astrophysics Data System (ADS)

Božović, I.; He, X.; Wu, J.; Bollinger, A. T.

2017-10-01

Cuprate superconductors exhibit many features, but the ultimate question is why the critical temperature (Tc) is so high. The fundamental dichotomy is between the weak-pairing, Bardeen-Cooper-Schrieffer (BCS) scenario, and Bose-Einstein condensation (BEC) of strongly-bound pairs. While for underdoped cuprates it is hotly debated which of these pictures is appropriate, it is commonly believed that on the overdoped side strongly-correlated fermion physics evolves smoothly into the conventional BCS behavior. Here, we test this dogma by studying the dependence of key superconducting parameters on doping, temperature, and external fields, in thousands of cuprate samples. The findings do not conform to BCS predictions anywhere in the phase diagram.

Sr 2IrO 4: Gateway to cuprate superconductivity?

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

Mitchell, J. F.

High temperature superconductivity in cuprates remains a defining challenge in condensed matter physics. Recently, a new set of related compounds based on Ir rather than Cu has been discovered that may be on the verge of superconductivity themselves or be able to shed new light on the underlying interactions responsible for superconductivity in the cuprates.

Model of electron pairs in electron-doped cuprates

NASA Astrophysics Data System (ADS)

Singh, R. J.; Khan, Shakeel

2016-07-01

In the order parameter of hole-doped cuprate superconductors in the pseudogap phase, two holes enter the order parameter from opposite sides and pass through various CuO2 cells jumping from one O2- to the other under the influence of magnetic field offered by the Cu2+ ions in that CuO2 cell and thus forming hole pairs. In the pseudogap phase of electron-doped cuprates, two electrons enter the order parameter at Cu2+ sites from opposite ends and pass from one Cu2+ site to the diagonally opposite Cu2+ site. Following this type of path, they are subjected to high magnetic fields from various Cu2+ ions in that cell. They do not travel from one Cu2+ site to the other along straight path but by helical path. As they pass through the diagonal, they face high to low to very high magnetic field. Therefore, frequency of helical motion and pitch goes on changing with the magnetic field. Just before reaching the Cu2+ ions at the exit points of all the cells, the pitch of the helical motion is enormously decreased and thus charge density at these sites is increased. So the velocity of electrons along the diagonal path is decreased. Consequently, transition temperature of electron-doped cuprates becomes less than that of hole-doped cuprates. Symmetry of the order parameter of the electron-doped cuprates has been found to be of 3dx2-y2 + iS type. It has been inferred that internal magnetic field inside the order parameter reconstructs the Fermi surface, which is requisite for superconductivity to take place. Electron pairs formed in the pseudogap phase are the precursors of superconducting order parameter when cooled below Tc.

Barium enema

MedlinePlus

Lower gastrointestinal series; Lower GI series; Colorectal cancer - lower GI series; Colorectal cancer - barium enema; Crohn disease - lower GI series; Crohn disease - barium enema; Intestinal blockage - lower GI series; Intestinal ...

Nernst effect from fluctuating pairs in the pseudogap phase of the cuprates.

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

Levchenko, A.; Norman, M. R.; Varlamov, A. A.

2011-01-31

The observation of a large Nernst signal in cuprates above the superconducting transition temperature has attracted much attention. A potential explanation is that it originates from superconducting fluctuations. Although the Nernst signal is indeed consistent with Gaussian fluctuations for overdoped cuprates, Gaussian theory fails to describe the temperature dependence seen for underdoped cuprates. Here, we consider the vertex correction to Gaussian theory resulting from the pseudogap. This yields a Nernst signal in good agreement with the data.

Barium release system

NASA Technical Reports Server (NTRS)

Lewis, B. W.; Stokes, C. S.; Smith, E. W.; Murphy, W. J. (Inventor)

1973-01-01

A chemical system is described for releasing a good yield of free barium neutral atoms and barium ions in the upper atmosphere and interplanetary space for the study of the geophysical properties of the medium. The barium is released in the vapor phase so that it can be ionized by solar radiation and also be excited to emit resonance radiation in the visible range. The ionized luminous cloud of barium becomes a visible indication of magnetic and electrical characteristics in space and allows determination of these properties over relatively large areas at a given time.

Incommensurate Phonon Anomaly and the Nature of Charge Density Waves in Cuprates

DOE PAGES

Miao, H.; Ishikawa, D.; Heid, R.; ...

2018-01-18

While charge density wave (CDW) instabilities are ubiquitous to superconducting cuprates, the different ordering wave vectors in various cuprate families have hampered a unified description of the CDW formation mechanism. Here, we investigate the temperature dependence of the low-energy phonons in the canonical CDW-ordered cuprate La 1.875Ba 0.125CuO 4. We discover that the phonon softening wave vector associated with CDW correlations becomes temperature dependent in the high-temperature precursor phase and changes from a wave vector of 0.238 reciprocal lattice units (r.l.u.) below the ordering transition temperature to 0.3 r.l.u. at 300 K. This high-temperature behavior also shows that “214”-type cupratesmore » can host CDW correlations at a similar wave vector to previously reported CDW correlations in non-214-type cuprates such as YBa 2Cu 3O 6+δ. This indicates that cuprate CDWs may arise from the same underlying instability despite their apparently different low-temperature ordering wave vectors.« less

Incommensurate Phonon Anomaly and the Nature of Charge Density Waves in Cuprates

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

Miao, H.; Ishikawa, D.; Heid, R.

While charge density wave (CDW) instabilities are ubiquitous to superconducting cuprates, the different ordering wave vectors in various cuprate families have hampered a unified description of the CDW formation mechanism. Here, we investigate the temperature dependence of the low-energy phonons in the canonical CDW-ordered cuprate La 1.875Ba 0.125CuO 4. We discover that the phonon softening wave vector associated with CDW correlations becomes temperature dependent in the high-temperature precursor phase and changes from a wave vector of 0.238 reciprocal lattice units (r.l.u.) below the ordering transition temperature to 0.3 r.l.u. at 300 K. This high-temperature behavior also shows that “214”-type cupratesmore » can host CDW correlations at a similar wave vector to previously reported CDW correlations in non-214-type cuprates such as YBa 2Cu 3O 6+δ. This indicates that cuprate CDWs may arise from the same underlying instability despite their apparently different low-temperature ordering wave vectors.« less

Sulphate removal from sodium sulphate-rich brine and recovery of barium as a barium salt mixture.

PubMed

Vadapalli, Viswanath R K; Zvimba, John N; Mulopo, Jean; Motaung, Solly

2013-01-01

Sulphate removal from sodium sulphate-rich brine using barium hydroxide and recovery of the barium salts has been investigated. The sodium sulphate-rich brine treated with different dosages of barium hydroxide to precipitate barium sulphate showed sulphate removal from 13.5 g/L to less than 400 mg/L over 60 min using a barium to sulphate molar ratio of 1.1. The thermal conversion of precipitated barium sulphate to barium sulphide achieved a conversion yield of 85% using coal as both a reducing agent and an energy source. The recovery of a pure mixture of barium salts from barium sulphide, which involved dissolution of barium sulphide and reaction with ammonium hydroxide resulted in recovery of a mixture of barium carbonate (62%) and barium hydroxide (38%), which is a critical input raw material for barium salts based acid mine drainage (AMD) desalination technologies. Under alkaline conditions of this barium salt mixture recovery process, ammonia gas is given off, while hydrogen sulfide is retained in solution as bisulfide species, and this provides basis for ammonium hydroxide separation and recovery for reuse, with hydrogen sulfide also recoverable for further industrial applications such as sulfur production by subsequent stripping.

Production of Zr-89 using sputtered yttrium coin targets 89Zr using sputtered yttrium coin targets.

PubMed

Queern, Stacy Lee; Aweda, Tolulope Aramide; Massicano, Adriana Vidal Fernandes; Clanton, Nicholas Ashby; El Sayed, Retta; Sader, Jayden Andrew; Zyuzin, Alexander; Lapi, Suzanne Elizabeth

2017-07-01

An increasing interest in zirconium-89 ( 89 Zr) can be attributed to the isotope's half-life which is compatible with antibody imaging using positron emission tomography (PET). The goal of this work was to develop an efficient means of production for 89 Zr that provides this isotope with high radionuclidic purity and specific activity. We investigated the irradiation of yttrium sputtered niobium coins and compared the yields and separation efficiency to solid yttrium coins. The sputtered coins were irradiated with an incident beam energy of 17.5MeV or 17.8MeV providing a degraded transmitted energy through an aluminum degrader of 12.5MeV or 12.8MeV, respectively, with various currents to determine optimal cyclotron conditions for 89 Zr production. Dissolution of the solid yttrium coin took 2h with 50mL of 2M HCl and dissolution of the sputtered coin took 15-30min with 4mL of 2M HCl. During the separation of 89 Zr from the solid yttrium coins, 77.9 ± 11.2% of the activity was eluted off in an average of 7.3mL of 1M oxalic acid whereas for the sputtered coins, 91 ± 6% was eluted off in an average of 1.2mL of 1M oxalic acid with 100% radionuclidic purity. The effective specific activity determined via DFO-SCN titration from the sputtered coins was 108±7mCi/μmol as compared to 20.3mCi/μmol for the solid yttrium coin production. ICP-MS analysis of the yttrium coin and the sputtered coins showed 99.99% yttrium removed with 178μg of yttrium in the final solution and 99.93-100% of yttrium removed with remaining range of 0-42μg of yttrium in the final solution, respectively. The specific activity calculated for the solid coin and 3 different sputtered coins using the concentration of Zr found via ICP-MS was 140±2mCi/μmol, 300±30mCi/μmol, 410±60mCi/μmol and 1719±5mCi/μmol, respectively. Labeling yields of the 89 Zr produced via sputtered targets for 89 Zr- DFO-trastuzumab were >98%. Overall, these results show the irradiation of yttrium sputtered niobium coins

Specific heat and Nernst effect of electron-doped cuprate superconductors

NASA Astrophysics Data System (ADS)

Balci, Hamza

This thesis consists of two separate studies on Pr2- xCexCuO4 (PCCO), a member of the electron-doped high temperature cuprate superconductor family: specific heat and the Nernst effect. We measured the specific heat of PCCO single crystals in order to probe the symmetry of the superconducting order parameter, to study the effect of oxygen reduction (annealing) on bulk properties of the crystals, and to determine proper ties like the condensation energy and the thermodynamic critical field. The order parameter symmetry has been established to be d-wave in the hole-doped cuprates. Experiments performed on electron-doped cuprates show conflicting results. Different experiments suggest s-wave symmetry, d-wave symmetry, or a transition from d-wave to s-wave symmetry with increasing cerium doping. However, most of these experiments are surface sensitive experiments. Specific heat, as a bulk method of probing the gap symmetry is essential in order to convincingly determine the gap symmetry. Our data proposes a way to reconcile all these conflicting results regarding the gap symmetry. In addition, prior specific heat measurements attempting to determine thermodynamic properties like the condensation energy were not successful due to inefficient methods of data analysis or poor sample quality. With improvements on sample quality and data analysis, we reliably determined these properties. The second part of this thesis is a study of the Nernst effect in PCCO thin films with different cerium dopings. We probed the superconducting fluctuations, studied transport phenomena in the normal state, and accurately measured H c2 by using the Nernst effect. After the discovery of the anomalous Nernst effect in the normal state of the hole-doped cuprates, many alternative explanations have been proposed. Vortex-like excitations above Tc, superconducting fluctuations, AFM fluctuations, and preformed Cooper pairs are some of these proposals. The electron-doped cuprates, due to their

Ultrasonic and elastic properties of Tl- and Hg-Based cuprate superconductors: a review

NASA Astrophysics Data System (ADS)

Abd-Shukor, R.

2018-01-01

This review is regarding the ultrasonic and elastic properties of Tl- and Hg-based cuprate superconductors. The objectives of this paper were to review the ultrasonic attenuation above the transition temperature ?, and sound velocity and elastic anomalies at ? in the Tl- and Hg-based cuprate superconductors. A discontinuity in the sound velocity and elastic moduli is observed near ? for the Hg-based and other cuprate high temperature superconductor but not the Tl-based superconductor. Ultrasonic attenuation peaks are observed between 200 and 250 K in almost all Tl- and Hg-based cuprate superconductors reported. These peaks were attributed to lattice stepping and oxygen ordering in the Tl-O and Hg-O layers. Some Tl- and Hg-based superconductors show attenuation peak near ?. However, this is not a common feature for the cuprate superconductors. The ultrasonic attenuation decrease rate below ? is slower than that expected from a Bardeen-Cooper-Schrieffer (BCS) and pseudo-gapped superconductor.

Experimental transport studies of yttrium barium copper oxide and lambda-DNA

NASA Astrophysics Data System (ADS)

Zhang, Yuexing

This dissertation consists of two parts. In Part I, we focus on the quasi-particle transport properties in the high temperature superconductor YBa2Cu3O7-delta (YBCO), probed by the thermal Hall conductivity (kappa xy). The thermal Hall conductivity selectively reflects the transport behaviors of the charge carriers. By measuring kappaxy in the normal state YBCO, we established a new method to determine the Wiedemann-Franz (WF) ratio in cuprates. We determined the Hall-channel WF ratio kappa xy/sigmaxyT in Cu and YBCO. In the latter, we uncovered a T-linear dependence and suppression of the Hallchannel WF ratio. The suppression of the Hall-channel WF ratio in systems with predominant electron-electron scattering will be discussed. Thermal transport behaviors of the quasi-particles in the mixed state were studied by measuring kappaxx and kappa xy in a high-purity YBCO crystal. From the field-dependence of the thermal conductivity kappaxx, we separated the quasi particle contribution (kappae) from the phonon background. In the Hall channel, we observed that the (weak-field) kappa xy increased 103-fold between T c (90 K) and 30 K, implying a 100-fold enhancement of the quasi-particle lifetime. We found that kappaxy exhibited a specific scaling behavior below ˜30 K. The implication of the scaling behavior will be discussed. In Part II, we describe an experiment on determining the electrical conductivity of the bacteriophage lambda-DNA, an issue currently under intense debate. We covalently bonded the DNA to Au electrodes by incorporating thiol modified dTTP into the 'sticky' ends of the lambda-DNA. Two-probe measurements on such molecules provided a lower bound for the resistivity rho > 10 6 mum at bias potentials up to 20 V, in conflict with recent claims of moderate to high conductivity. We stress the importance of eliminating salt residues in these measurements.

Electron doped layered nickelates: Spanning the phase diagram of the cuprates

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

Botana, Antia S.; Pardo, Victor; Norman, Michael R.

2017-07-01

Pr4Ni3O8 is an overdoped analog of hole-doped layered cuprates. Here we show via ab initio calculations that Ce-doped Pr4Ni3O8 (Pr3CeNi3O8) has the same electronic structure as the antiferromagnetic insulating phase of parent cuprates.We find that substantial Ce doping should be thermodynamically stable and that other 4+ cations would yield a similar antiferromagnetic insulating state, arguing this configuration is robust for layered nickelates of low-enough valence. The analogies with cuprates at different d fillings suggest that intermediate Ce-doping concentrations near 1/8 should be an appropriate place to search for superconductivity in these low-valence Ni oxides.

Interatomic Potentials for Structure Simulation of Alkaline-Earth Cuprates

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

Eremin, N.N.; Leonyuk, L.I.; Urusov, V.S.

2001-05-01

A specific potential model of interionic interactions was derived in which the crystal structures of alkaline-earth cuprates were satisfactorily described and some of their physical properties were predicted. It was found that a harmonic three-particle O-Cu-O potential and some Morse-type contributions to the simple Buckingham-type Cu-O repulsive potential enable one to improve essentially the results of crystal structure modeling for cuprates. The obtained potential set seems to be well transferable for different cuprates, despite the variety in linkages of the CuO{sub 4} groups. In the present work this potential set model was applied in the crystal structure modeling for Ca{submore » 2}CuO{sub 3}, CaCuO{sub 2}, SrCuO{sub 3}, (Sr{sub 1.19}Ca{sub 0.73})Cu{sub 2}O{sub 4}, and BaCuO{sub 2}. Some elastic and energetic properties of the compounds under question were predicted.« less

Visualizing electron pockets in cuprate superconductors

NASA Astrophysics Data System (ADS)

Das, Tanmoy; Markiewicz, R. S.; Bansil, A.; Balatsky, A. V.

2012-06-01

Fingerprints of the electron pocket in cuprates have been obtained only in numerous magnetotransport measurements, but its absence in spectroscopic observations poses a long-standing mystery. We develop a theoretical tool to provide ways to detect electron pockets via spectroscopies including scanning tunneling microscopy (STM) spectra, inelastic neutron scattering (INS), and angle-resolved photoemission spectroscopy (ARPES). We show that the quasiparticle-interference (QPI) pattern, measured by STM, shows an additional seven q vectors associated with the scattering on the electron pocket than that on the hole pocket. Furthermore, the Bogolyubov quasiparticle scatterings of the electron pocket lead to a second magnetic resonance mode in the INS spectra at a higher resonance energy. Finally, we reanalyze some STM, INS, and ARPES experimental data of several cuprates which dictates the direct fingerprints of electron pockets in these systems.

Barium enema (image)

MedlinePlus

A barium enema is performed to examine the walls of the colon. During the procedure, a well lubricated enema tube is inserted gently into the rectum. The barium, a radiopaque (shows up on X-ray) contrast ...

Barium light source method and apparatus

NASA Technical Reports Server (NTRS)

Curry, John J. (Inventor); MacDonagh-Dumler, Jeffrey (Inventor); Anderson, Heidi M. (Inventor); Lawler, James E. (Inventor)

2002-01-01

Visible light emission is obtained from a plasma containing elemental barium including neutral barium atoms and barium ion species. Neutral barium provides a strong green light emission in the center of the visible spectrum with a highly efficient conversion of electrical energy into visible light. By the selective excitation of barium ionic species, emission of visible light at longer and shorter wavelengths can be obtained simultaneously with the green emission from neutral barium, effectively providing light that is visually perceived as white. A discharge vessel contains the elemental barium and a buffer gas fill therein, and a discharge inducer is utilized to induce a desired discharge temperature and barium vapor pressure therein to produce from the barium vapor a visible light emission. The discharge can be induced utilizing a glow discharge between electrodes in the discharge vessel as well as by inductively or capacitively coupling RF energy into the plasma within the discharge vessel.

Barium toxicosis in a dog.

PubMed

Adam, Fiona H; Noble, Peter J M; Swift, Simon T; Higgins, Brent M; Sieniawska, Christine E

2010-09-01

A 2-year-old 14.9-kg (32.8-lb) neutered female Shetland Sheepdog was admitted to the University of Liverpool Small Animal Teaching Hospital for evaluation of acute collapse. At admission, the dog was tachypneic and had reduced limb reflexes and muscle tone in all limbs consistent with diffuse lower motor neuron dysfunction. The dog was severely hypokalemic (1.7 mEq/L; reference range, 3.5 to 5.8 mEq/L). Clinical status of the dog deteriorated; there was muscle twitching, flaccid paralysis, and respiratory failure, which was considered a result of respiratory muscle weakness. Ventricular arrhythmias and severe acidemia (pH, 7.18; reference range, 7.35 to 7.45) developed. Intoxication was suspected, and plasma and urine samples submitted for barium analysis had barium concentrations comparable with those reported in humans with barium toxicosis. Analysis of barium concentrations in 5 control dogs supported the diagnosis of barium toxicosis in the dog. Fluids and potassium supplementation were administered IV. The dog recovered rapidly. Electrolyte concentrations measured after recovery were consistently unremarkable. Quantification of plasma barium concentration 56 days after the presumed episode of intoxication revealed a large decrease; however, the plasma barium concentration remained elevated, compared with that in control dogs. To our knowledge, this case represented the first description of barium toxicosis in the veterinary literature. Barium toxicosis can cause life-threatening hypokalemia; however, prompt supportive treatment can yield excellent outcomes. Barium toxicosis is a rare but important differential diagnosis in animals with hypokalemia and appropriate clinical signs.

Absolute measurements of fast neutrons using yttrium.

PubMed

Roshan, M V; Springham, S V; Rawat, R S; Lee, P; Krishnan, M

2010-08-01

Yttrium is presented as an absolute neutron detector for pulsed neutron sources. It has high sensitivity for detecting fast neutrons. Yttrium has the property of generating a monoenergetic secondary radiation in the form of a 909 keV gamma-ray caused by inelastic neutron interaction. It was calibrated numerically using MCNPX and does not need periodic recalibration. The total yttrium efficiency for detecting 2.45 MeV neutrons was determined to be f(n) approximately 4.1x10(-4) with an uncertainty of about 0.27%. The yttrium detector was employed in the NX2 plasma focus experiments and showed the neutron yield of the order of 10(8) neutrons per discharge.

Insights on the Cuprate High Energy Anomaly Observed in ARPES

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

Moritz, Brian

2011-08-16

Recently, angle-resolved photoemission spectroscopy has been used to highlight an anomalously large band renormalization at high binding energies in cuprate superconductors: the high energy 'waterfall' or high energy anomaly (HEA). The anomaly is present for both hole- and electron-doped cuprates as well as the half-filled parent insulators with different energy scales arising on either side of the phase diagram. While photoemission matrix elements clearly play a role in changing the aesthetic appearance of the band dispersion, i.e. creating a 'waterfall'-like appearance, they provide an inadequate description for the physics that underlies the strong band renormalization giving rise to the HEA.more » Model calculations of the single-band Hubbard Hamiltonian showcase the role played by correlations in the formation of the HEA and uncover significant differences in the HEA energy scale for hole- and electron-doped cuprates. In addition, this approach properly captures the transfer of spectral weight accompanying doping in a correlated material and provides a unifying description of the HEA across both sides of the cuprate phase diagram. We find that the anomaly demarcates a transition, or cross-over, from a quasiparticle band at low binding energies near the Fermi level to valence bands at higher binding energy, assumed to be of strong oxygen character.« less

Hole-doped cuprate high temperature superconductors

NASA Astrophysics Data System (ADS)

Chu, C. W.; Deng, L. Z.; Lv, B.

2015-07-01

Hole-doped cuprate high temperature superconductors have ushered in the modern era of high temperature superconductivity (HTS) and have continued to be at center stage in the field. Extensive studies have been made, many compounds discovered, voluminous data compiled, numerous models proposed, many review articles written, and various prototype devices made and tested with better performance than their nonsuperconducting counterparts. The field is indeed vast. We have therefore decided to focus on the major cuprate materials systems that have laid the foundation of HTS science and technology and present several simple scaling laws that show the systematic and universal simplicity amid the complexity of these material systems, while referring readers interested in the HTS physics and devices to the review articles. Developments in the field are mostly presented in chronological order, sometimes with anecdotes, in an attempt to share some of the moments of excitement and despair in the history of HTS with readers, especially the younger ones.

Modeling and minimization of barium sulfate scale

Treesearch

Alan W. Rudie; Peter W. Hart

2006-01-01

The majority of the barium present in the pulping process exits the digester as barium carbonate. Barium carbonate dissolves in the bleach plant when the pH drops below 7 and, if barium and sulfate concentrations are too high, begins to precipitate as barium sulfate. Barium is difficult to control because a mill cannot avoid this carbonate-to-sulfate transition using...

Oxide perovskite crystals for HTSC film substrates microwave applications

NASA Technical Reports Server (NTRS)

Bhalla, A. S.; Guo, Ruyan

1995-01-01

The research focused upon generating new substrate materials for the deposition of superconducting yttrium barium cuprate (YBCO) has yielded several new hosts in complex perovskites, modified perovskites, and other structure families. New substrate candidates such as Sr(Al(1/2)Ta(1/2))O3 and Sr(Al(1/2)Nb(1/2))O3, Ba(Mg(1/3)Ta(2/3))O3 in complex oxide perovskite structure family and their solid solutions with ternary perovskite LaAlO3 and NdGaO3 are reported. Conventional ceramic processing techniques were used to fabricate dense ceramic samples. A laser heated molten zone growth system was utilized for the test-growth of these candidate materials in single crystal fiber form to determine crystallographic structure, melting point, thermal, and dielectric properties as well as to make positive identification of twin free systems. Some of those candidate materials present an excellent combination of properties suitable for microwave HTSC substrate applications.

Barium Peritonitis in Small Animals

PubMed Central

KO, Jae Jin; MANN, F. A. (Tony)

2014-01-01

ABSTRACT Barium peritonitis is extremely rare, but is difficult to treat and may be life-threatening. Barium suspension leakage from the gastrointestinal tract into the abdominal cavity has a time-dependent and synergistically deleterious effect in patients who have generalized bacterial peritonitis. The severity of barium peritonitis is dependent on the quantity of barium in the abdominal cavity. Barium sulfate leakage results in hypovolemia and hypoproteinemia by worsening the exudation of extracellular fluid and albumin. Abdominal fluid analysis is a useful and efficient method to diagnose barium peritonitis. Serial radiographs may not be a reliable or timely diagnostic technique. Initial aggressive fluid resuscitation and empirical broad-spectrum antibiotic treatment should be instituted promptly, followed quickly by celiotomy. During exploratory surgical intervention, copious irrigation and direct wiping with gauze are employed to remove as much barium as possible. Omentectomy should be considered when needed to expedite barium removal. Despite aggressive medical and surgical treatments, postoperative prognosis is guarded to poor due to complications, such as acute vascular shock, sepsis, diffuse peritonitis, hypoproteninemia, electrolyte imbalance, cardiac arrest, small bowel obstruction related to progression of granulomas and adhesions in the abdominal cavity. Therefore, intensive postoperative monitoring and prompt intervention are necessary to maximize chances for a positive outcome. For those that do survive, small bowel obstruction is a potential consequence due to progression of abdominal adhesions. PMID:24430662

Barium Depletion in Hollow Cathode Emitters

NASA Technical Reports Server (NTRS)

Polk, James E.; Capece, Angela M.; Mikellides, Ioannis G.; Katz, Ira

2009-01-01

The effect of tungsten erosion, transport and redeposition on the operation of dispenser hollow cathodes was investigated in detailed examinations of the discharge cathode inserts from an 8200 hour and a 30,352 hour ion engine wear test. Erosion and subsequent re-deposition of tungsten in the electron emission zone at the downstream end of the insert reduces the porosity of the tungsten matrix, preventing the ow of barium from the interior. This inhibits the interfacial reactions of the barium-calcium-aluminate impregnant with the tungsten in the pores. A numerical model of barium transport in the internal xenon discharge plasma shows that the barium required to reduce the work function in the emission zone can be supplied from upstream through the gas phase. Barium that flows out of the pores of the tungsten insert is rapidly ionized in the xenon discharge and pushed back to the emitter surface by the electric field and drag from the xenon ion flow. This barium ion flux is sufficient to maintain a barium surface coverage at the downstream end greater than 0.6, even if local barium production at that point is inhibited by tungsten deposits. The model also shows that the neutral barium pressure exceeds the equilibrium vapor pressure of the impregnant decomposition reaction over much of the insert length, so the reactions are suppressed. Only a small region upstream of the zone blocked by tungsten deposits is active and supplies the required barium. These results indicate that hollow cathode failure models based on barium depletion rates in vacuum dispenser cathodes are very conservative.

A Superconducting Dual-Channel Photonic Switch.

PubMed

Srivastava, Yogesh Kumar; Manjappa, Manukumara; Cong, Longqing; Krishnamoorthy, Harish N S; Savinov, Vassili; Pitchappa, Prakash; Singh, Ranjan

2018-06-05

The mechanism of Cooper pair formation and its underlying physics has long occupied the investigation into high temperature (high-T c ) cuprate superconductors. One of the ways to unravel this is to observe the ultrafast response present in the charge carrier dynamics of a photoexcited specimen. This results in an interesting approach to exploit the dissipation-less dynamic features of superconductors to be utilized for designing high-performance active subwavelength photonic devices with extremely low-loss operation. Here, dual-channel, ultrafast, all-optical switching and modulation between the resistive and the superconducting quantum mechanical phase is experimentally demonstrated. The ultrafast phase switching is demonstrated via modulation of sharp Fano resonance of a high-T c yttrium barium copper oxide (YBCO) superconducting metamaterial device. Upon photoexcitation by femtosecond light pulses, the ultrasensitive cuprate superconductor undergoes dual dissociation-relaxation dynamics, with restoration of superconductivity within a cycle, and thereby establishes the existence of dual switching windows within a timescale of 80 ps. Pathways are explored to engineer the secondary dissociation channel which provides unprecedented control over the switching speed. Most importantly, the results envision new ways to accomplish low-loss, ultrafast, and ultrasensitive dual-channel switching applications that are inaccessible through conventional metallic and dielectric based metamaterials. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fermi-surface reconstruction by stripe order in cuprate superconductors

NASA Astrophysics Data System (ADS)

Laliberté, Francis

2012-02-01

The origin of pairing in a superconductor resides in the underlying normal state. In the cuprate high-temperature superconductor YBCO, application of a magnetic field to suppress superconductivity reveals a ground state that appears to break the translational symmetry of the lattice, pointing to some density-wave order [1,2,3]. In another cuprate, Eu-LSCO, the onset of stripe order - a modulation of spin and charge densities - at low temperature is well established [4]. By a comparative study of thermoelectric transport in the cuprates YBCO and Eu-LSCO, we show that the two materials exhibit a very similar process of Fermi-surface reconstruction as a function of temperature and doping [5,6]. This strongly suggests that Fermi-surface reconstruction is caused by stripe order in both cases, compelling evidence that stripe order is a generic tendency of hole-doped cuprates.[4pt] Work done in collaboration with J. Chang, N. Doiron-Leyraud, E. Hassinger, R. Daou, D. LeBoeuf, M. Rondeau, B. J. Ramshaw, R. Liang, D. A. Bonn, W. N. Hardy, S. Pyon, T. Takayama, H. Takagi, I. Sheikin, L. Malone, C. Proust, K. Behnia and L. Taillefer.[4pt] [1] N. Doiron-Leyraud et al., Nature 447, 565 (2007).[0pt] [2] D. LeBoeuf et al., Nature 450, 533 (2007).[0pt] [3] D. LeBoeuf et al., Phys. Rev. B 83, 054506 (2011).[0pt] [4] J. Fink et al., Phys. Rev. B 83, 092503 (2011).[0pt] [5] J. Chang et al., Phys. Rev. Lett. 104, 057005 (2010).[0pt] [6] F. Lalibert'e et al., Nat. Commun. 2, 432 (2011).

Evolution of superconducting gap and metallic ground state in cuprates from transport

NASA Astrophysics Data System (ADS)

Taillefer, Louis

2006-03-01

We report on fundamental characteristics of the ground state of cuprates in the limit of T=0, for both normal and superconducting states, obtained from transport measurements on high-quality single crystals of YBCO and Tl-2201, as a function of hole concentration. The superconducting gap is extracted from thermal conductivity; it is found to scale with the superconducting transition temperature throughout the overdoped regime, with a gap-to-Tc ratio of 5 [1]. The normal state is accessed by suppressing superconductivity with magnetic fields up to 60 T and is characterized by the limiting behavior of its electrical resistivity; while carrier localization is observed in YBCO at low temperature for carrier concentrations p below 0.1 hole/planar Cu, at p=0.1 and above the material remains highly metallic down to T=0 [2]. This shows that the non-superconducting state of underdoped cuprates, deep in the pseudogap phase, is remarkably similar to that of strongly overdoped cuprates, e.g. at p=0.3. We compare these results with similar measurements on other cuprates and discuss their implication for our understanding of the cuprate phase diagram. [1] In collaboration with: D.G. Hawthorn, S.Y. Li, M. Sutherland, E. Boaknin, R.W. Hill, C. Proust, F. Ronning, M. Tanatar, J. Paglione, D. Peets, R. Liang, D.A. Bonn, W.N. Hardy, and N.N. Kolesnikov. [2] In collaboration with: C. Proust, M. Sutherland, N. Doiron- Leyraud, S.Y. Li, R. Liang, D.A. Bonn, W.N. Hardy, N.E. Hussey, S. Adachi, S. Tajima, J. Levallois, and M. Narbone.

What is really extraordinary in cuprate superconductors?

DOE PAGES

Bozovic, I.; Wu, J.; He, X.; ...

2018-03-07

Over the course of three decades of intense study, apart from the exceptionally high critical temperature, many unusual properties of cuprates have been discovered, notably including resistivity linear in temperature, electronic Raman continuum and optical absorption extending throughout the infrared region, pseudogap, hour-glass spin excitation spectrum, etc. However, each of these features have been also observed in other materials, including some that are not even superconducting at all. Here, we describe an extensive experiment in which over 2,000 films of the La 2-xSr xCuO 4 have been synthesized and studied in detail over the course of the last twelve years.more » We argue here that, uniquely, in the cuprates an unusual superconducting state, that defies the standard BCS description, develops from an unusual metallic state, in which the rotational symmetry of the electron fluid is spontaneously broken.« less

Interpretation of scanning tunneling quasiparticle interference and impurity states in cuprates

DOE PAGES

Kreisel, Andreas; Choubey, Peayush; Berlijn, Tom; ...

2015-05-27

We apply a recently developed method combining first principles based Wannier functions with solutions to the Bogoliubov–de Gennes equations to the problem of interpreting STM data in cuprate superconductors. We show that the observed images of Zn on the surface of Bi 2Sr 2CaCu 2O 8 can only be understood by accounting for the tails of the Cu Wannier functions, which include significant weight on apical O sites in neighboring unit cells. This calculation thus puts earlier crude “filter” theories on a microscopic foundation and solves a long-standing puzzle. We then study quasiparticle interference phenomena induced by out-of-plane weak potentialmore » scatterers, and show how patterns long observed in cuprates can be understood in terms of the interference of Wannier functions above the surface. Furthermore, our results show excellent agreement with experiment and enable a better understanding of novel phenomena in the cuprates via STM imaging.« less

Interpretation of scanning tunneling quasiparticle interference and impurity states in cuprates.

PubMed

Kreisel, A; Choubey, Peayush; Berlijn, T; Ku, W; Andersen, B M; Hirschfeld, P J

2015-05-29

We apply a recently developed method combining first principles based Wannier functions with solutions to the Bogoliubov-de Gennes equations to the problem of interpreting STM data in cuprate superconductors. We show that the observed images of Zn on the surface of Bi_{2}Sr_{2}CaCu_{2}O_{8} can only be understood by accounting for the tails of the Cu Wannier functions, which include significant weight on apical O sites in neighboring unit cells. This calculation thus puts earlier crude "filter" theories on a microscopic foundation and solves a long-standing puzzle. We then study quasiparticle interference phenomena induced by out-of-plane weak potential scatterers, and show how patterns long observed in cuprates can be understood in terms of the interference of Wannier functions above the surface. Our results show excellent agreement with experiment and enable a better understanding of novel phenomena in the cuprates via STM imaging.

Superconducting Mercury-Based Cuprate Films with a Zero-Resistance Transition Temperature of 124 Kelvin

NASA Astrophysics Data System (ADS)

Tsuei, C. C.; Gupta, A.; Trafas, G.; Mitzi, D.

1994-03-01

The synthesis of high-quality films of the recently discovered mercury-based cuprate films with high transition temperatures has been plagued by problems such as the air sensitivity of the cuprate precursor and the volatility of Hg and HgO. These processing difficulties have been circumvented by a technique of atomic-scale mixing of the HgO and cuprate precursors, use of a protective cap layer, and annealing in an appropriate Hg and O_2 environment. With this procedure, a zero-resistance transition temperature as high as 124 kelvin in c axis-oriented epitaxial HgBa_2CaCu_2O6+δ films has been achieved.

Superconducting mercury-based cuprate films with a zero-resistance transition temperature of 124 Kelvin.

PubMed

Tsuei, C C; Gupta, A; Trafas, G; Mitzi, D

1994-03-04

The synthesis of high-quality films of the recently discovered mercury-based cuprate films with high transition temperatures has been plagued by problems such as the air sensitivity of the cuprate precursor and the volatility of Hg and HgO. These processing difficulties have been circumvented by a technique of atomic-scale mixing of the HgO and cuprate precursors, use of a protective cap layer, and annealing in an appropriate Hg and O(2) environment. With this procedure, a zero-resistance transition temperature as high as 124 kelvin in c axis-oriented epitaxial HgBa(2)CaCu(2)O(6+delta) films has been achieved.

Radioactive Barium Ion Trap Based on Metal-Organic Framework for Efficient and Irreversible Removal of Barium from Nuclear Wastewater.

PubMed

Peng, Yaguang; Huang, Hongliang; Liu, Dahuan; Zhong, Chongli

2016-04-06

Highly efficient and irreversible capture of radioactive barium from aqueous media remains a serious task for nuclear waste disposal and environmental protection. To address this task, here we propose a concept of barium ion trap based on metal-organic framework (MOF) with a strong barium-chelating group (sulfate and sulfonic acid group) in the pore structures of MOFs. The functionalized MOF-based ion traps can remove >90% of the barium within the first 5 min, and the removal efficiency reaches 99% after equilibrium. Remarkably, the sulfate-group-functionalized ion trap demonstrates a high barium uptake capacity of 131.1 mg g(-1), which surpasses most of the reported sorbents and can selectively capture barium from nuclear wastewater, whereas the sulfonic-acid-group-functionalized ion trap exhibits ultrafast kinetics with a kinetic rate constant k2 of 27.77 g mg(-1) min(-1), which is 1-3 orders of magnitude higher than existing sorbents. Both of the two MOF-based ion traps can capture barium irreversibly. Our work proposes a new strategy to design barium adsorbent materials and provides a new perspective for removing radioactive barium and other radionuclides from nuclear wastewater for environment remediation. Besides, the concrete mechanisms of barium-sorbent interactions are also demonstrated in this contribution.

Competing pseudogap and impurity effects on the normal-state specific heat properties of cuprate superconductors

NASA Astrophysics Data System (ADS)

Dzhumanov, S.; Karimboev, E. X.

2014-07-01

In this paper, we show that the pseudogap in the excitation spectra of high-Tc cuprates together with the impurity phase and charge inhomogeneity plays key roles in determining the essential features of their anomalous specific heat properties observed above Tc. We consider the doped cuprate superconductor as a multi-carrier model system (which consists of intrinsic and extrinsic polarons and pre-formed bosonic Cooper pairs) and study the competing pseudogap and impurity effects on the normal-state electronic specific heat of high-Tc cuprates taking into account charge inhomogeneities. We argue that unconventional electron-phonon interactions are responsible for the precursor Cooper pairing in the polaronic band below a mean-field temperature T∗ and the existence of a pseudogap above Tc in the cuprates. The electronic specific heat Ce(T) of doped cuprates below T∗ is calculated taking into account three contributions coming from the excited components of Cooper pairs, the ideal Bose-gas of incoherent Cooper pairs and the unpaired carriers in the impurity band. Above T∗, two contributions to Ce(T) coming from the unpaired intrinsic and extrinsic polarons are calculated within the two-component degenerate Fermi-gas model. By comparing our results with the experimental Ce(T) data obtained for La- and Y-based cuprates, we find that the observed behaviors of Ce(T) (below and above T∗) are similar to the calculated results for Ce(T) and the BCS-type jumps of Ce(T) at T∗ may be depressed by the impurity effects and may become more or less pronounced BCS-type anomalies in Ce(T) .

Biokinetics of yttrium and comparison with its geochemical twin holmium

DOE PAGES

Leggett, Rich

2017-06-01

The transition metal yttrium (Y, atomic number 39) is chemically similar to elements in the lanthanide family (atomic numbers 57-71, lanthanum through lutetium) and is always present with the lanthanides in rare earth ores. Yttrium and the lanthanide holmium are particularly close chemical and physical analogues and are referred to as geochemical twins because they typically show little fractionation in geological material. Extensive measurements on rocks, soils, and meteorites indicate that the Y/Ho mass concentration ratio rarely falls far from the “chondritic” or “solar system” ratio of ~26. Our paper presents a new biokinetic model for yttrium in adult humansmore » and examines whether yttrium and holmium may be biological as well as geochemical twins. Collected data on yttrium and holmium in plants and human tissues do not allow precise derivations of Y/Ho concentration ratios but with occasional exceptions yield ratios that are reasonably consistent with chondritic values. Predictions of the time-dependent behavior of yttrium in adult humans based on the yttrium model presented here closely approximate predictions of the behavior of holmium based on a previously developed model for holmium. We know that yttrium and holmium are close biological analogues, but the available comparative data are too limited and imprecise to reveal whether there are any significant differences in their biological behavior.« less

Temperature and doping dependence of the high-energy kink in cuprates.

PubMed

Zemljic, M M; Prelovsek, P; Tohyama, T

2008-01-25

It is shown that spectral functions within the extended t-J model, evaluated using the finite-temperature diagonalization of small clusters, exhibit the high-energy kink in single-particle dispersion consistent with recent angle-resolved photoemission results on hole-doped cuprates. The kink and waterfall-like features persist up to large doping and to temperatures beyond J; hence, the origin can be generally attributed to strong correlations and incoherent hole propagation at large binding energies. In contrast, our analysis predicts that electron-doped cuprates do not exhibit these phenomena in photoemission.

Rare earths, the lanthanides, yttrium and scandium

USGS Publications Warehouse

Hedrick, J.B.

2006-01-01

In 2005, rare earths were not mined in the United States. The major supplier, Molycorp, continued to maintain a large stockpile of rare-earth concentrates and compounds. Consumption decreased of refined rare-earth products. The United States remained a major importer and exporter of rare earths in 2005. During the same period, yttrium was not mined or refined in the US. Hence, supply of yttrium compounds for refined yttrium products came from China, France and Japan. Scandium was not also mined. World production was primarily in China, Russia and Ukraine. Demand for rare earths in 2006 is expected to be closely tied to economic conditions in the US.

Systematic study of electron-phonon coupling to oxygen modes across the cuprates

NASA Astrophysics Data System (ADS)

Johnston, S.; Vernay, F.; Moritz, B.; Shen, Z.-X.; Nagaosa, N.; Zaanen, J.; Devereaux, T. P.

2010-08-01

The large variations in Tc across the cuprate families is one of the major unsolved puzzles in condensed matter physics and is poorly understood. Although there appears to be a great deal of universality in the cuprates, several orders of magnitude changes in Tc can be achieved through changes in the chemical composition and structure of the unit cell. In this paper we formulate a systematic examination of the variations in electron-phonon coupling to oxygen phonons in the cuprates, incorporating a number of effects arising from several aspects of chemical composition and doping across cuprate families. It is argued that the electron-phonon coupling is a very sensitive probe of the material-dependent variations in chemical structure, affecting the orbital character of the band crossing the Fermi level, the strength of local electric fields arising from structural-induced symmetry breaking, doping-dependent changes in the underlying band structure, and ionicity of the crystal governing the ability of the material to screen c -axis perturbations. Using electrostatic Ewald calculations and known experimental structural data, we establish a connection between the material’s maximal Tc at optimal doping and the strength of coupling to c -axis modes. We demonstrate that materials with the largest coupling to the out-of-phase bond-buckling (B1g) oxygen phonon branch also have the largest Tc ’s. In light of this observation we present model Tc calculations using a two-well model where phonons work in conjunction with a dominant pairing interaction, presumably due to spin fluctuations, indicating how phonons can generate sizeable enhancements to Tc despite the relatively small coupling strengths. Combined, these results can provide a natural framework for understanding the doping and material dependence of Tc across the cuprates.

Superconducting structure

DOEpatents

Kwon, Chuhee; Jia, Quanxi; Foltyn, Stephen R.

2003-04-01

A superconductive structure including a dielectric oxide substrate, a thin buffer layer of a superconducting material thereon; and, a layer of a rare earth-barium-copper oxide superconducting film thereon the thin layer of yttrium-barium-copper oxide, the rare earth selected from the group consisting of samarium, gadolinium, ytterbium, erbium, neodymium, dysprosium, holmium, lutetium, a combination of more than one element from the rare earth group and a combination of one or more elements from the rare earth group with yttrium, the buffer layer of superconducting material characterized as having chemical and structural compatibility with the dielectric oxide substrate and the rare earth-barium-copper oxide superconducting film is provided.

Superconducting Structure

DOEpatents

Kwon, Chuhee; Jia, Quanxi; Foltyn, Stephen R.

2005-09-13

A superconductive structure including a dielectric oxide substrate, a thin buffer layer of a superconducting material thereon; and, a layer of a rare earth-barium-copper oxide superconducting film thereon the thin layer of yttrium-barium-copper oxide, the rare earth selected from the group consisting of samarium, gadolinium, ytterbium, erbium, neodymium, dysprosium, holmium, lutetium, a combination of more than one element from the rare earth group and a combination of one or more elements from the rare earth group with yttrium, the buffer layer of superconducting material characterized as having chemical and structural compatibility with the dielectric oxide substrate and the rare earth-barium-copper oxide superconducting film is provided.

Structural phase transitions in yttrium under ultrahigh pressures

NASA Astrophysics Data System (ADS)

Samudrala, Gopi K.; Tsoi, Georgiy M.; Vohra, Yogesh K.

2012-09-01

X-ray diffraction studies were carried out on the rare earth metal yttrium up to 177 GPa in a diamond anvil cell at room temperature. Yttrium was compressed to 37% of its initial volume at the highest pressure. The rare earth crystal structure sequence hcp → Sm type → dhcp → mixed(dhcp + fcc) → distorted fcc (dfcc) is observed in yttrium below 50 GPa. The dfcc (hR24) phase has been observed to persist in the pressure range of 50-95 GPa. A structural transition from dfcc to a low symmetry phase has been observed in yttrium at 99 ± 4 GPa with a volume change of - 2.6%. This low symmetry phase has been identified as a monoclinic C2/m phase, which has also been observed in other rare earth elements under high pressures. The appearance of this low symmetry monoclinic phase in yttrium shows that its electronic structure under extreme conditions resembles that of heavy rare earth metals, with a significant increase in d-band character of the valence electrons and possibly some f-electron states near the Fermi level.

Structural phase transitions in yttrium under ultrahigh pressures.

PubMed

Samudrala, Gopi K; Tsoi, Georgiy M; Vohra, Yogesh K

2012-09-12

X-ray diffraction studies were carried out on the rare earth metal yttrium up to 177 GPa in a diamond anvil cell at room temperature. Yttrium was compressed to 37% of its initial volume at the highest pressure. The rare earth crystal structure sequence hcp → Sm type → dhcp → mixed(dhcp + fcc) → distorted fcc (dfcc) is observed in yttrium below 50 GPa. The dfcc (hR24) phase has been observed to persist in the pressure range of 50-95 GPa. A structural transition from dfcc to a low symmetry phase has been observed in yttrium at 99 ± 4 GPa with a volume change of - 2.6%. This low symmetry phase has been identified as a monoclinic C2/m phase, which has also been observed in other rare earth elements under high pressures. The appearance of this low symmetry monoclinic phase in yttrium shows that its electronic structure under extreme conditions resembles that of heavy rare earth metals, with a significant increase in d-band character of the valence electrons and possibly some f-electron states near the Fermi level.

Collapse of superconductivity in cuprates via ultrafast quenching of phase coherence

DOE PAGES

Boschini, F.; da Silva Neto, E. H.; Razzoli, E.; ...

2018-04-02

The possibility of driving phase transitions in low-density condensates through the loss of phase coherence alone has far-reaching implications for the study of quantum phases of matter. This has inspired the development of tools to control and explore the collective properties of condensate phases via phase fluctuations. Electrically gated oxide interfaces, ultracold Fermi atoms and cuprate superconductors, which are characterized by an intrinsically small phase stiffness, are paradigmatic examples where these tools are having a dramatic impact. In this study, we use light pulses shorter than the internal thermalization time to drive and probe the phase fragility of the Bimore » 2Sr 2CaCu 2O 8+δ cuprate superconductor, completely melting the superconducting condensate without affecting the pairing strength. The resulting ultrafast dynamics of phase fluctuations and charge excitations are captured and disentangled by time-resolved photoemission spectroscopy. This work demonstrates the dominant role of phase coherence in the superconductor-to-normal state phase transition and offers a benchmark for non-equilibrium spectroscopic investigations of the cuprate phase diagram.« less

Collapse of superconductivity in cuprates via ultrafast quenching of phase coherence

NASA Astrophysics Data System (ADS)

Boschini, F.; da Silva Neto, E. H.; Razzoli, E.; Zonno, M.; Peli, S.; Day, R. P.; Michiardi, M.; Schneider, M.; Zwartsenberg, B.; Nigge, P.; Zhong, R. D.; Schneeloch, J.; Gu, G. D.; Zhdanovich, S.; Mills, A. K.; Levy, G.; Jones, D. J.; Giannetti, C.; Damascelli, A.

2018-05-01

The possibility of driving phase transitions in low-density condensates through the loss of phase coherence alone has far-reaching implications for the study of quantum phases of matter. This has inspired the development of tools to control and explore the collective properties of condensate phases via phase fluctuations. Electrically gated oxide interfaces1,2, ultracold Fermi atoms3,4 and cuprate superconductors5,6, which are characterized by an intrinsically small phase stiffness, are paradigmatic examples where these tools are having a dramatic impact. Here we use light pulses shorter than the internal thermalization time to drive and probe the phase fragility of the Bi2Sr2CaCu2O8+δ cuprate superconductor, completely melting the superconducting condensate without affecting the pairing strength. The resulting ultrafast dynamics of phase fluctuations and charge excitations are captured and disentangled by time-resolved photoemission spectroscopy. This work demonstrates the dominant role of phase coherence in the superconductor-to-normal state phase transition and offers a benchmark for non-equilibrium spectroscopic investigations of the cuprate phase diagram.

Collapse of superconductivity in cuprates via ultrafast quenching of phase coherence

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

Boschini, F.; da Silva Neto, E. H.; Razzoli, E.

The possibility of driving phase transitions in low-density condensates through the loss of phase coherence alone has far-reaching implications for the study of quantum phases of matter. This has inspired the development of tools to control and explore the collective properties of condensate phases via phase fluctuations. Electrically gated oxide interfaces, ultracold Fermi atoms and cuprate superconductors, which are characterized by an intrinsically small phase stiffness, are paradigmatic examples where these tools are having a dramatic impact. In this study, we use light pulses shorter than the internal thermalization time to drive and probe the phase fragility of the Bimore » 2Sr 2CaCu 2O 8+δ cuprate superconductor, completely melting the superconducting condensate without affecting the pairing strength. The resulting ultrafast dynamics of phase fluctuations and charge excitations are captured and disentangled by time-resolved photoemission spectroscopy. This work demonstrates the dominant role of phase coherence in the superconductor-to-normal state phase transition and offers a benchmark for non-equilibrium spectroscopic investigations of the cuprate phase diagram.« less

Electronic structure of CuTeO 4 and its relationship to cuprates

DOE PAGES

Botana, Antia S.; Norman, Michael R.

2017-03-13

Based on first-principles calculations, the electronic structure of CuTeO 4 is discussed in the context of superconducting cuprates. Despite some significant crystallographic differences, we find that CuTeO 4 is similar to these cuprates, exhibiting a quasi-two-dimensional electronic structure that involves hybridized Cu- d and O-p states in the vicinity of the Fermi level, along with an antiferromagnetic insulating ground state. Lastly, hole- doping this material by substituting Te 6+ with Sb 5+ would be of significant interest.

Enhancing critical current density of cuprate superconductors

DOEpatents

Chaudhari, Praveen

2015-06-16

The present invention concerns the enhancement of critical current densities in cuprate superconductors. Such enhancement of critical current densities include using wave function symmetry and restricting movement of Abrikosov (A) vortices, Josephson (J) vortices, or Abrikosov-Josephson (A-J) vortices by using the half integer vortices associated with d-wave symmetry present in the grain boundary.

Theory of superconductivity and spin excitations in cuprates

NASA Astrophysics Data System (ADS)

Plakida, Nikolay M.

2018-06-01

A microscopic theory of high-temperature superconductivity in strongly correlated systems as cuprates is presented. The two-subband extended Hubbard model is considered where the intersite Coulomb repulsion and electron-phonon interaction are taken into account. The low-energy spin excitations are considered within the t-J model.

Barite (Barium)

USGS Publications Warehouse

Johnson, Craig A.; Piatak, Nadine M.; Miller, M. Michael; Schulz, Klaus J.; DeYoung,, John H.; Seal, Robert R.; Bradley, Dwight C.

2017-12-19

Barite (barium sulfate, BaSO4) is vital to the oil and gas industry because it is a key constituent of the mud used to drill oil and gas wells. Elemental barium is an additive in optical glass, ceramic glazes, and other products. Within the United States, barite is produced mainly from mines in Nevada. Imports in 2011 (the latest year for which complete data were available) accounted for 78 percent of domestic consumption and came mostly from China.Barite deposits can be divided into the following four main types: bedded-sedimentary; bedded-volcanic; vein, cavity-fill, and metasomatic; and residual. Bedded-sedimentary deposits, which are found in sedimentary rocks with characteristics of high biological productivity during sediment accumulation, are the major sources of barite production and account for the majority of reserves, both in the United States and worldwide. In 2013, China and India were the leading producers of barite, and they have large identified resources that position them to be significant producers for the foreseeable future. The potential for undiscovered barite resources in the United States and in many other countries is considerable, however. The expected tight supply and rising costs in the coming years will likely be met by increased production from such countries as Kazakhstan, Mexico, Morocco, and Vietnam.Barium has limited mobility in the environment and exposed barium in the vicinity of barite mines poses minimal risk to human or ecosystem health. Of greater concern is the potential for acidic metal-bearing drainage at sites where the barite ores or waste rocks contain abundant sulfide minerals. This risk is lessened naturally if the host rocks at the site are acid-neutralizing, and the risk can also be lessened by engineering measures.

Competing Quantum Orderings in Cuprate Superconductors:

NASA Astrophysics Data System (ADS)

Martin, I.; Ortiz, G.; Balatsky, A. V.; Bishop, A. R.

We present a minimal model for cuprate superconductors. At the unrestricted mean-field level, the model produces homogeneous superconductivity at large doping, striped superconductivity in the underdoped regime and various antiferromagnetic phases at low doping and for high temperatures. On the underdoped side, the superconductor is intrinsically inhomogeneous and global phase coherence is achieved through Josephson-like coupling of the superconducting stripes. The model is applied to calculate experimentally measurable ARPES spectra.

The problem of the barium stars

NASA Technical Reports Server (NTRS)

Bohm-Vitense, E.; Nemec, J.; Proffitt, C.

1984-01-01

Ultraviolet observations of barium stars and other cool stars with peculiar element abundances are reported. Those observations attempted to find hot white dwarf companions. Among six real barium stars studied, only Zeta Cap was found to have a white dwarf companion. Among seven mild, or marginal, barium stars studied, at least three were found to have hot subluminous companions. It is likely that all of them have white dwarf companions.

Nanocomposite scintillator, detector, and method

DOEpatents

Cooke, D Wayne [Santa Fe, NM; McKigney, Edward A [Los Alamos, NM; Muenchausen, Ross E [Los Alamos, NM; Bennett, Bryan L [Los Alamos, NM

2009-04-28

A compact includes a mixture of a solid binder and at least one nanopowder phosphor chosen from yttrium oxide, yttrium tantalate, barium fluoride, cesium fluoride, bismuth germanate, zinc gallate, calcium magnesium pyrosilicate, calcium molybdate, calcium chlorovanadate, barium titanium pyrophosphate, a metal tungstate, a cerium doped nanophosphor, a bismuth doped nanophosphor, a lead doped nanophosphor, a thallium doped sodium iodide, a doped cesium iodide, a rare earth doped pyrosilicate, or a lanthanide halide. The compact can be used in a radiation detector for detecting ionizing radiation.

Binding and Leakage of Barium in Alginate Microbeads

PubMed Central

Mørch, Yrr A.; Qi, Meirigeng; Gundersen, Per Ole M.; Formo, Kjetil; Lacik, Igor; Skjåk-Bræk, Gudmund; Oberholzer, Jose; Strand, Berit L.

2013-01-01

Microbeads of alginate cross-linked with Ca2+ and/or Ba2+ are popular matrices in cell-based therapy. The aim of this study was to quantify the binding of barium in alginate microbeads and its leakage under in vitro and accumulation under in vivo conditions. Low concentrations of barium (1 mM) in combination with calcium (50 mM) and high concentrations of barium (20 mM) in gelling solutions were used for preparation of microbeads made of high-G and high-M alginates. High-G microbeads accumulated barium from gelling solution and contained higher concentrations of divalent ions for both low- and high-Ba exposure compared to high-G microbeads exposed to calcium solely and to high-M microbeads for all gelling conditions. Although most of the unbound divalent ions were removed during the wash and culture steps, leakage of barium was still detected during storage. Barium accumulation in blood and femur bone of mice implanted with high-G beads was found to be dose-dependent. Estimated barium leakage relevant to transplantation to diabetic patients with islets in alginate microbeads showed that the leakage was 2.5 times lower than the tolerable intake value given by WHO for high-G microbeads made using low barium concentration. The similar estimate gave 1.5 times higher than is the tolerable intake value for the high-G microbeads made using high barium concentration. In order to reduce the risk of barium accumulation that may be of safety concern, the microbeads made of high-G alginate gelled with a combination of calcium and low concentration of barium ions is recommended for islet transplantation. PMID:22700168

Binding and leakage of barium in alginate microbeads.

PubMed

Mørch, Yrr A; Qi, Meirigeng; Gundersen, Per Ole M; Formo, Kjetil; Lacik, Igor; Skjåk-Braek, Gudmund; Oberholzer, Jose; Strand, Berit L

2012-11-01

Microbeads of alginate crosslinked with Ca(2+) and/or Ba(2+) are popular matrices in cell-based therapy. The aim of this study was to quantify the binding of barium in alginate microbeads and its leakage under in vitro and accumulation under in vivo conditions. Low concentrations of barium (1 mM) in combination with calcium (50 mM) and high concentrations of barium (20 mM) in gelling solutions were used for preparation of microbeads made of high-G and high-M alginates. High-G microbeads accumulated barium from gelling solution and contained higher concentrations of divalent ions for both low- and high-Ba exposure compared with high-G microbeads exposed to calcium solely and to high-M microbeads for all gelling conditions. Although most of the unbound divalent ions were removed during the wash and culture steps, leakage of barium was still detected during storage. Barium accumulation in blood and femur bone of mice implanted with high-G beads was found to be dose-dependent. Estimated barium leakage relevant to transplantation to diabetic patients with islets in alginate microbeads showed that the leakage was 2.5 times lower than the tolerable intake value given by WHO for high-G microbeads made using low barium concentration. The similar estimate gave 1.5 times higher than is the tolerable intake value for the high-G microbeads made using high barium concentration. To reduce the risk of barium accumulation that may be of safety concern, the microbeads made of high-G alginate gelled with a combination of calcium and low concentration of barium ions is recommended for islet transplantation. Copyright © 2012 Wiley Periodicals, Inc.

Spin-polaron nature of fermion quasiparticles and their d-wave pairing in cuprate superconductors

NASA Astrophysics Data System (ADS)

Val'kov, V. V.; Dzebisashvili, D. M.; Barabanov, A. F.

2016-11-01

In the framework of the spin-fermion model, to which the Emery model is reduced in the limit of strong electron correlations, it is shown that the fermion quasiparticles in cuprate high- T c superconductors (HTSCs) arise under a strong effect of exchange coupling between oxygen holes and spins of copper ions. This underlies the spin-polaron nature of fermion quasiparticles in cuprate HTSCs. The Cooper instability with respect to the d-wave symmetry of the order parameter is revealed for an ensemble of such quasiparticles. For the normal phase, the spin-polaron concept allows us to reproduce the fine details in the evolution of the Fermi surface with the changes in the doping level x observed in experiment for La2-xSrxCuO4. The calculated T-x phase diagram correlates well with the available experimental data for cuprate HTSCs.

Rare earths, the lanthanides, yttrium and scandium

USGS Publications Warehouse

Bedinger, G.; Bleiwas, D.

2012-01-01

In 2011, rare earths were recovered from bastnasite concentrates at the Mountain Pass Mine in California. Consumption of refined rare-earth products decreased in 2011 from 2010. U.S. rare-earth imports originated primarily from China, with lesser amounts from Austria, Estonia, France and Japan. The United States imported all of its demand for yttrium metal and yttrium compounds, with most of it originating from China. Scandium was imported in various forms and processed domestically.

Infrared conductivity of cuprates using Yang-Rice-Zhang ansatz: Review of our recent investigations

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

Singh, Navinder; Sharma, Raman

2015-05-15

A review of our recent investigations related to the ac transport properties in the psedogapped state of cuprate high temperature superconductors is presented. For our theoretical calculations we use a phenomenological Green’s function proposed by Yang, Rice and Zhang (YRZ). This is based upon the renormalized mean-field theory of the Hubbard model and takes into account the strong electron-electron interaction present in Cuprates. The pseudogap is also taken into account through a proposed self energy. We have tested the form of the Green’s function by computing ac conductivity of cuprates and then compared with experimental results. We found agreement betweenmore » theory and experiment in reproducing the doping evolution of ac conductivity but there is a problem with absolute magnitudes and their frequency dependence. This shows a partial success of the YRZ ansatz. The ways to rectify it are suggested and worked out.« less

Observed Barium Emission Rates

NASA Technical Reports Server (NTRS)

Stenbaek-Nielsen, H. C.; Wescott, E. M.; Hallinan, T. J.

1993-01-01

The barium releases from the CRRES satellite have provided an opportunity for verifying theoretically calculated barium ion and neutral emission rates. Spectra of the five Caribbean releases in the summer of 1991 were taken with a spectrograph on board a U.S. Air Force jet aircraft. Because the line of sight release densities are not known, only relative rates could be obtained. The observed relative rates agree well with the theoretically calculated rates and, together with other observations, confirm the earlier detailed theoretical emission rates. The calculated emission rates can thus with good accuracy be used with photometric observations. It has been postulated that charge exchange between neutral barium and oxygen ions represents a significant source for ionization. If so. it should be associated with emissions at 4957.15 A and 5013.00 A, but these emissions were not detected.

Hybrid crystals of cuprates and iron-based superconductors

NASA Astrophysics Data System (ADS)

Xia, Dai; Cong-Cong, Le; Xian-Xin, Wu; Jiang-Ping, Hu

2016-07-01

We propose two possible new compounds, Ba2CuO2Fe2As2 and K2CuO2Fe2Se2, which hybridize the building blocks of two high temperature superconductors, cuprates and iron-based superconductors. These compounds consist of square CuO2 layers and antifluorite-type Fe2 X 2 (X = As, Se) layers separated by Ba/K. The calculations of binding energies and phonon spectra indicate that they are dynamically stable, which ensures that they may be experimentally synthesized. The Fermi surfaces and electronic structures of the two compounds inherit the characteristics of both cuprates and iron-based superconductors. These compounds can be superconductors with intriguing physical properties to help to determine the pairing mechanisms of high T c superconductivity. Project supported by the National Basic Research Program of China (Grant No. 2015CB921300), the National Natural Science Foundation of China (Grant Nos. 1190020 and 11334012), and the Strategic Priority Research Program of Chinese Academy of Sciences (Grant No. XDB07000000).

Coastal barium cycling at the West Antarctic Peninsula

NASA Astrophysics Data System (ADS)

Pyle, K. M.; Hendry, K. R.; Sherrell, R. M.; Meredith, M. P.; Venables, H.; Lagerström, M.; Morte-Ródenas, A.

2017-05-01

Barium cycling in the ocean is associated with a number of processes, including the production and recycling of organic matter, freshwater fluxes, and phenomena that affect alkalinity. As a result, the biogeochemical cycle of barium offers insights into past and present oceanic conditions, with barium currently used in various forms as a palaeoproxy for components of organic and inorganic carbon storage, and as a quasi-conservative water mass tracer. However, the nature of the oceanic barium cycle is not fully understood, particularly in cases where multiple processes may be interacting simultaneously with the dissolved and particulate barium pools. This is particularly the case in coastal polar regions such as the West Antarctic Peninsula, where biological drawdown and remineralisation occur in tandem with sea ice formation and melting, glacial meltwater input, and potential fluxes from shelf sediments. Here, we use a high-precision dataset of dissolved barium (Bad) from a grid of stations adjacent to the West Antarctic Peninsula in conjunction with silicic acid (Si(OH)4), the oxygen isotope composition of water, and salinity measurements, to determine the relative control of various coastal processes on the barium cycle throughout the water column. There is a strong correlation between Bad and Si(OH)4 present in deeper samples, but nevertheless persists significantly in surface waters. This indicates that the link between biogenic opal and barium is not solely due to barite precipitation and dissolution at depth, but is supplemented by an association between Bad and diatom tests in surface waters, possibly due to barite formation within diatom-dominated phytodetritus present in the photic zone. Sea-ice meltwater appears to exert a significant secondary control on barium concentrations, likely due to non-conservative biotic or abiotic processes acting as a sink for Bad within the sea ice itself, or sea-ice meltwater stimulating non-siliceous productivity that acts

Nanoparticles of barium induce apoptosis in human phagocytes.

PubMed

Mores, Luana; França, Eduardo Luzia; Silva, Núbia Andrade; Suchara, Eliane Aparecida; Honorio-França, Adenilda Cristina

2015-01-01

Nutrients and immunological factors of breast milk are essential for newborn growth and the development of their immune system, but this secretion can contain organic and inorganic toxins such as barium. Colostrum contamination with barium is an important issue to investigate because this naturally occurring element is also associated with human activity and industrial pollution. The study evaluated the administration of barium nanoparticles to colostrum, assessing the viability and functional activity of colostral mononuclear phagocytes. Colostrum was collected from 24 clinically healthy women (aged 18-35 years). Cell viability, superoxide release, intracellular Ca(2+) release, and phagocyte apoptosis were analyzed in the samples. Treatment with barium lowered mononuclear phagocyte viability, increased superoxide release, and reduced intracellular calcium release. In addition, barium increased cell death by apoptosis. These data suggest that nanoparticles of barium in colostrum are toxic to cells, showing the importance of avoiding exposure to this element.

Superconductivity, pseudo-gap, and stripe correlations in high-Tc cuprates

NASA Astrophysics Data System (ADS)

Zhang, Zailan; Denis, Sylvain; Lebert, Blair W.; Bertran, Francois; Le Fèvre, Patrick; Taleb-Ibrahimi, Amina; Castellan, John-Paul; Bolloc'h, David Le; Jacques, Vincent L. R.; Sidis, Yvan; Baptiste, Benoît; Decorse, Claudia; Berthet, Patrick; Perfetti, Luca; d'Astuto, Matteo

2018-05-01

Under-doped La-214 cuprates show a charge- and spin-modulation known as "stripes" [1]. These stripe modulations are (quasi)-static close to 1/8 hole doping where superconductivity is suppressed. The pseudo-gap phase of other cuprate compounds recently also revealed charge modulation, but interpreted rather as a charge density wave (CDW) [2-4], that possibly competes with superconductivity. In this context, to better understand the interplay between the stripe phase and the superconductivity, we use angle-resolved photoemission spectroscopy to study the electronic band structure and gap in La-214 cuprates near 1/8 doping (La2-x-yNdySrxCuO4 (x = 0.12; y = 0.0 & 0.4)) and compare with the previous results in the same system [5] and La1.86Ba0.14CuO4 [6]. Our data shows a loss of spectral intensity towards the end of the Fermi arcs, that is possibly due to a strong renormalisation, as already pointed out elsewhere [6], with a noisy but still measurable gap. On the nodal direction no gap is observed within our statistics, but a sizeable decrease in intensity with temperature. Moreover, we do not see any shadow band, but our Fermi surface can be well modelled with a single electron band calculation in the tight binding approximation, even very close to the 1/8 doping La2-x-yNdySrxCuO4 with and without Nd substitution.

A spatial interpretation of emerging superconductivity in lightly doped cuprates

NASA Astrophysics Data System (ADS)

Deutscher, Guy; de Gennes, Pierre-Gilles

The formation of domains comprising alternating 'hole rich' and 'hole poor' ladders recently observed by Scanning Tunneling Microscopy by Kohsaka et al., on lightly hole doped cuprates, is interpreted in terms of an attractive mechanism which favors the presence of doped holes on Cu sites located each on one side of an oxygen atom. This mechanism leads to a geometrical pattern of alternating hole-rich and hole-poor ladders with a periodicity equal to 4 times the lattice spacing in the CuO plane, as observed experimentally. Cuprates supraconducteurs peu dopés : une interprétation des structures spatiales. Des arrangements électroniques réguliers ont été détectés récemment par Kohsaka et al. dans des cuprates sous dopés (via une sonde tunnel locale). Certaines paires Cu-O-Cu sont « actives », et forment une échelle. Les autres sites sont peu actifs. Pour expliquer ces structures, nous postulons que, lorsqu'une liaison Cu-O-Cu est occupée par deux trous, la distance (Cu-Cu) rétrécit et l'intégrale de transfert (t) est fortement augmentée. Ceci peut engendrer des paires localisées (réelles ou virtuelles). Aux taux de dopage étudiés, la période de répétition vaudrait 4 mailles élémentaires.

Selection of plants for phytoremediation of barium-polluted flooded soils.

PubMed

Ribeiro, Paulo Roberto Cleyton de Castro; Viana, Douglas Gomes; Pires, Fábio Ribeiro; Egreja Filho, Fernando Barboza; Bonomo, Robson; Cargnelutti Filho, Alberto; Martins, Luiz Fernando; Cruz, Leila Beatriz Silva; Nascimento, Mauro César Pinto

2018-05-10

The use of barite (BaSO4) in drilling fluids for oil and gas activities makes barium a potential contaminant in case of spills onto flooded soils, where low redox conditions may increase barium sulfate solubility. In order to select plants able to remove barium in such scenarios, the following species were evaluated on barium phytoextraction capacity: Brachiaria arrecta, Cyperus papyrus, Eleocharis acutangula, E. interstincta, Nephrolepsis cf. rivularis, Oryza sativa IRGA 424, O. sativa BRS Tropical, Paspalum conspersum, and Typha domingensis. Plants were grown in pots and exposed to six barium concentrations: 0, 2.5, 5.0, 10.0, 30.0, and 65.0 mg kg -1 . To simulate flooding conditions, each pot was kept with a thin water film over the soil surface (∼1.0 cm). Plants were evaluated for biomass yield and barium removal. The highest amount of barium was observed in T. domingensis biomass, followed by C. papyrus. However, the latter exported most of the barium to the aerial part of the plant, especially at higher BaCl 2 doses, while the former accumulated barium preferentially in the roots. Thus, barium removal with C. papyrus could be achieved by simply harvesting aerial biomass. The high amounts of barium in T. domingensis and C. papyrus resulted from the combination of high barium concentration in plant tissues with high biomass production. These results make T. domingensis and C. papyrus potential candidates for phytoremediation schemes to remove barium from flooded soils. Copyright © 2018 Elsevier Ltd. All rights reserved.

Barium appendicitis after upper gastrointestinal imaging.

PubMed

Novotny, Nathan M; Lillemoe, Keith D; Falimirski, Mark E

2010-02-01

Barium appendicitis (BA) is a rarely seen entity with fewer than 30 reports in the literature. However, it is a known complication of barium imaging. To report a case of BA in a patient whose computed tomography (CT) scan was initially read as foreign body ingestion. An 18-year-old man presented with right lower quadrant pain after upper gastrointestinal imaging 2 weeks prior. A CT scan was obtained of his abdomen and pelvis that revealed a finding that was interpreted as a foreign body at the area of the terminal ileum. A plain X-ray study of the abdomen revealed radiopaque appendicoliths. Pathology confirmed the diagnosis of barium appendicitis. BA is a rare entity and the pathogenesis is unclear. Shorter intervals between barium study and presentation with appendicitis usually correlate with fewer complications. Copyright (c) 2010 Elsevier Inc. All rights reserved.

Hematological, biochemical, and histopathological impacts of barium chloride and barium carbonate accumulation in soft tissues of male Sprague-Dawley rats.

PubMed

Mohammed, Amany Tharwat; Ismail, Hager Tarek H

2017-12-01

The present study was designed to investigate the hematotoxicity, sero-biochemical and histological changes due to the accumulation of BaCl 2 and BaCO 3 , the most important barium salts in our daily lives, in different soft tissues including the liver, kidney, heart, and spleen of adult rats after an oral exposure for 30 consecutive days, and to explain the different mechanisms by which this metal can exert these impacts. For this purpose, adult male rats were divided into three main groups of 15 animals each: group I, serving as controls, group II, receiving BaCl 2 orally in a dose of 179 mg barium/kg b.wt, and group III, receiving BaCO 3 orally in a dose of 418 mg barium/kg b.wt. for 30 consecutive days. Obviously, normocytic normochromic anemia was evident in both barium groups. Serum biochemical analysis revealed significant declines in glutathione peroxidase, catalase, superoxide dismutase, and urea with significant elevations in malondialdehyde, lactate dehydrogenase, and creatine kinase levels. Hyperphosphatemia, hypokalemia, hypocalcemia, and hypochloremia were also evident in both barium groups. Besides, residual analysis of both barium salts in different body organs revealed significantly abundant barium residues in the liver, spleen, heart, and kidney, respectively in both barium salts groups. Moreover, splenic tissue showed hemosiderosis, peritubular congestion, and necrotic glomeruli with intratubular hemorrhage. Sever subepicardial congestion with intramuscular edema was evident in the heart. In conclusion, BaCl 2 and BaCO 3 were able to deliver mortalities, antioxidant enzymes exhaustion, and a sort of normocytic normochromic anemia, as well as marked disturbances in cardiac, hepatic, and renal functions due to the accumulation of these two salts in the soft tissues. Therefore, these results demonstrate the unrecognized toxicity of those two barium salts due to their accumulation in various soft tissues of the body and so, this needs to reconsider

Nanoparticles of barium induce apoptosis in human phagocytes

PubMed Central

Mores, Luana; França, Eduardo Luzia; Silva, Núbia Andrade; Suchara, Eliane Aparecida; Honorio-França, Adenilda Cristina

2015-01-01

Purpose Nutrients and immunological factors of breast milk are essential for newborn growth and the development of their immune system, but this secretion can contain organic and inorganic toxins such as barium. Colostrum contamination with barium is an important issue to investigate because this naturally occurring element is also associated with human activity and industrial pollution. The study evaluated the administration of barium nanoparticles to colostrum, assessing the viability and functional activity of colostral mononuclear phagocytes. Methods Colostrum was collected from 24 clinically healthy women (aged 18–35 years). Cell viability, superoxide release, intracellular Ca2+ release, and phagocyte apoptosis were analyzed in the samples. Results Treatment with barium lowered mononuclear phagocyte viability, increased superoxide release, and reduced intracellular calcium release. In addition, barium increased cell death by apoptosis. Conclusion These data suggest that nanoparticles of barium in colostrum are toxic to cells, showing the importance of avoiding exposure to this element. PMID:26451108

Size-dependent cytotoxicity of yttrium oxide nanoparticles on primary osteoblasts in vitro

NASA Astrophysics Data System (ADS)

Zhou, Guoqiang; Li, Yunfei; Ma, Yanyan; Liu, Zhu; Cao, Lili; Wang, Da; Liu, Sudan; Xu, Wenshi; Wang, Wenying

2016-05-01

Yttrium oxide nanoparticles are an excellent host material for the rare earth metals and have high luminescence efficiency providing a potential application in photodynamic therapy and biological imaging. In this study, the effects of yttrium oxide nanoparticles with four different sizes were investigated using primary osteoblasts in vitro. The results demonstrated that the cytotoxicity generated by yttrium oxide nanoparticles depended on the particle size, and smaller particles possessed higher toxicological effects. For the purpose to elucidate the relationship between reactive oxygen species generation and cell damage, cytomembrane integrity, intracellular reactive oxygen species level, mitochondrial membrane potential, cell apoptosis rate, and activity of caspase-3 in cells were then measured. Increased reactive oxygen species level was also observed in a size-dependent way. Thus, our data demonstrated that exposure to yttrium oxide nanoparticles resulted in a size-dependent cytotoxicity in cultured primary osteoblasts, and reactive oxygen species generation should be one possible damage pathway for the toxicological effects produced by yttrium oxide particles. The results may provide useful information for more rational applications of yttrium oxide nanoparticles in the future.

Development of 2024 AA-Yttrium composites by Spark Plasma Sintering

NASA Astrophysics Data System (ADS)

Vidyasagar, CH S.; Karunakar, D. B.

2018-04-01

The method of fabrication of MMNCs is quite a challenge, which includes advanced processing techniques like Spark Plasma Sintering (SPS), etc. The objective of the present work is to fabricate aluminium based MMNCs with the addition of small amounts of yttrium using Spark Plasma Sintering and to evaluate their mechanical and microstructure properties. Samples of 2024 AA with yttrium ranging from 0.1% to 0.5 wt% are fabricated by Spark Plasma Sintering (SPS). Hardness of the samples is determined using Vickers hardness testing machine. The metallurgical characterization of the samples is evaluated by Optical Microscopy (OM), Field Emission Scanning Electron Microscopy (FE-SEM). Unreinforced 2024 AA sample is also fabricated as a benchmark to compare its properties with those of the composite developed. It is found that the yttrium addition increases the above mentioned properties by altering the precipitation kinetics and intermetallic formation to some extent and then decreases gradually when yttrium wt% increases beyond 0.3 wt%. High density (˂ 99.75) is achieved in the samples and highest hardness achieved is 114 Hv, fabricated by spark plasma sintering and uniform distribution of yttrium is observed.

Hertzsprung-Russell diagram and mass distribution of barium stars

NASA Astrophysics Data System (ADS)

Escorza, A.; Boffin, H. M. J.; Jorissen, A.; Van Eck, S.; Siess, L.; Van Winckel, H.; Karinkuzhi, D.; Shetye, S.; Pourbaix, D.

2017-12-01

With the availability of parallaxes provided by the Tycho-Gaia Astrometric Solution, it is possible to construct the Hertzsprung-Russell diagram (HRD) of barium and related stars with unprecedented accuracy. A direct result from the derived HRD is that subgiant CH stars occupy the same region as barium dwarfs, contrary to what their designations imply. By comparing the position of barium stars in the HRD with STAREVOL evolutionary tracks, it is possible to evaluate their masses, provided the metallicity is known. We used an average metallicity [Fe/H] = -0.25 and derived the mass distribution of barium giants. The distribution peaks around 2.5 M⊙ with a tail at higher masses up to 4.5 M⊙. This peak is also seen in the mass distribution of a sample of normal K and M giants used for comparison and is associated with stars located in the red clump. When we compare these mass distributions, we see a deficit of low-mass (1 - 2 M⊙) barium giants. This is probably because low-mass stars reach large radii at the tip of the red giant branch, which may have resulted in an early binary interaction. Among barium giants, the high-mass tail is however dominated by stars with barium indices of less than unity, based on a visual inspection of the barium spectral line; that is, these stars have a very moderate barium line strength. We believe that these stars are not genuine barium giants, but rather bright giants, or supergiants, where the barium lines are strengthened because of a positive luminosity effect. Moreover, contrary to previous claims, we do not see differences between the mass distributions of mild and strong barium giants. Full Table A.1 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/608/A100

Quantum oscillations from the reconstructed Fermi surface in electron-doped cuprate superconductors

NASA Astrophysics Data System (ADS)

Higgins, J. S.; Chan, M. K.; Sarkar, Tarapada; McDonald, R. D.; Greene, R. L.; Butch, N. P.

2018-04-01

We have studied the electronic structure of electron-doped cuprate superconductors via measurements of high-field Shubnikov–de Haas oscillations in thin films. In optimally doped Pr2‑x Ce x CuO4±δ and La2‑x Ce x CuO4±δ , quantum oscillations indicate the presence of a small Fermi surface, demonstrating that electronic reconstruction is a general feature of the electron-doped cuprates, despite the location of the superconducting dome at very different doping levels. Negative high-field magnetoresistance is correlated with an anomalous low-temperature change in scattering that modifies the amplitude of quantum oscillations. This behavior is consistent with effects attributed to spin fluctuations.

Universal optimal hole-doping concentration in single-layer high-temperature cuprate superconductors

NASA Astrophysics Data System (ADS)

Honma, T.; Hor, P. H.

2006-09-01

We argue that in cuprate physics there are two types, hole content per CuO2 plane (Ppl) and the corresponding hole content per unit volume (P3D), of hole-doping concentrations for addressing physical properties that are two dimensional (2D) and three dimensional (3D) in nature, respectively. We find that the superconducting transition temperature (Tc) varies systematically with P3D as a superconducting 'dome' with a universal optimal hole-doping concentration of P3Dopt = 1.6 × 1021 cm-3 for single-layer high-temperature superconductors. We suggest that P3Dopt determines the upper bound of the electronic energy of underdoped single-layer high-Tc cuprates.

Barium determination in gastric contents, blood and urine by inductively coupled plasma mass spectrometry in the case of oral barium chloride poisoning.

PubMed

Łukasik-Głębocka, Magdalena; Sommerfeld, Karina; Hanć, Anetta; Grzegorowski, Adam; Barałkiewicz, Danuta; Gaca, Michał; Zielińska-Psuja, Barbara

2014-01-01

A serious case of barium intoxication from suicidal ingestion is reported. Oral barium chloride poisoning with hypokalemia, neuromuscular and cardiac toxicity, treated with intravenous potassium supplementation and hemodialysis, was confirmed by the determination of barium concentrations in gastric contents, blood, serum and urine using the inductively coupled plasma mass spectrometry method. Barium concentrations in the analyzed specimens were 20.45 µg/L in serum, 150 µg/L in blood, 10,500 µg/L in urine and 63,500 µg/L in gastric contents. Results were compared with barium levels obtained from a non-intoxicated person. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Superconductivity in interacting interfaces of cuprate-based heterostructures

NASA Astrophysics Data System (ADS)

Di Castro, Daniele; Balestrino, Giuseppe

2018-07-01

Low dimensional superconducting systems have been the subject of numerous studies in the recent past, with the aim of achieving a higher and higher critical temperature (T c ). The recent improvement in film deposition techniques has allowed the realization of artificial heterostructures, with atomically flat surfaces and interfaces, where novel properties appear that are not present in the single constituent. For instance, quasi-2D superconductivity was found at the interface between different oxides. In this review we analyze, in particular, the quasi-2D superconductivity occurring at the interface between two non-superconducting oxides, mostly cuprates. Throughout a comparison of the superconducting properties of different oxide heterostructures and superlattices, we propose a phenomenological explanation of the behavior of the T c as a function of the number of conducting CuO2 planes. This is achieved by introducing two different interactions between the superconducting 2D sheets. This interpretation is finally extended also to standard high T c cuprates, contributing to the solution of the long-standing question of the dependence of T c on the number of CuO2 planes in these systems.

BARIUM AND STRONTIUM CONCENTRATIONS IN EYE TISSUE

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

Sowden, E.; Pirie, A.

1958-12-01

The stroniium and barium conient of the differeni parts of the eye has been estimated by the method of activation analysis in cattie, rabbit, and man. The pigmented parts of the eye coatain more stroatium and barium than the other parts, and barium in particular is concentrated in the choroid of the cow. These results are discussed in relation to the presence of high concentrations of zinc in the choroidal tapetum lucidum of other animals. (auth)

Cuprate diamagnetism in the presence of a pseudogap: Beyond the standard fluctuation formalism

NASA Astrophysics Data System (ADS)

Boyack, Rufus; Chen, Qijin; Varlamov, A. A.; Levin, K.

2018-02-01

It is often claimed that among the strongest evidence for preformed-pair physics in the cuprates are the experimentally observed large values for the diamagnetic susceptibility and Nernst coefficient. These findings are most apparent in the underdoped regime, where a pseudogap is also evident. While the conventional (Gaussian) fluctuation picture has been applied to address these results, this preformed-pair approach omits the crucial effects of a pseudogap. In this paper we remedy this omission by computing the diamagnetic susceptibility and Nernst coefficient in the presence of a normal state gap. We find a large diamagnetic response for a range of temperatures much higher than the transition temperature. In particular, we report semiquantitative agreement with the measured diamagnetic susceptibility onset temperatures, over the entire range of hole dopings. Notable is the fact that at the lower critical doping of the superconducting dome, where the transition temperature vanishes and the pseudogap onset temperature remains large, the onset temperature for both diamagnetic and transverse thermoelectric transport coefficients tends to zero. Due to the importance attributed to the cuprate diamagnetic susceptibility and Nernst coefficient, this work helps to clarify the extent to which pairing fluctuations are a component of the cuprate pseudogap.

Thermochemical hydrogen production via a cycle using barium and sulfur - Reaction between barium sulfide and water

NASA Technical Reports Server (NTRS)

Ota, K.; Conger, W. L.

1977-01-01

The reaction between barium sulfide and water, a reaction found in several sulfur based thermochemical cycles, was investigated kinetically at 653-866 C. Gaseous products were hydrogen and hydrogen sulfide. The rate determining step for hydrogen formation was a surface reaction between barium sulfide and water. An expression was derived for the rate of hydrogen formation.

Phenomenological view at the two-component physics of cuprates

NASA Astrophysics Data System (ADS)

Teitel'baum, G. B.

2017-08-01

In the search for mechanisms of high- T c superconductivity it is critical to know the electronic spectrum in the pseudogap phase from which superconductivity evolves. The lack of ARPES data for every cuprate family precludes an agreement as to its structure, doping and temperature dependence and the role of charge ordering. No approach has been developed yet to address the issue theoretically, and we limit ourselves by the phenomenological analysis of the experimental data. We argue that, in the Fermi-liquid-like regime ubiquitous in underdoped cuprates, the spectrum consists of holes on the Fermi arcs and an electronic pocket in contrast to the idea of the Fermi surface reconstruction via charge ordering. At high temperatures, the electrons are dragged by holes while at lower temperatures they get decoupled. The longstanding issue of the origin of the negative Hall coefficient in YBCO and Hg1201 at low temperature is resolved: the electronic contribution prevails, as its mobility becomes temperature independent, while the mobility of holes, scattered by the shortwavelength charge density waves, decreases.

Formation of Yttrium Oxysulfide Phosphor at Room Temperature

NASA Astrophysics Data System (ADS)

Shoji, Masahiko; Sakurai, Kenji

2005-12-01

Europium-doped yttrium oxysulfide (Y2O2S:Eu) phosphor was successfully synthesized at room temperature from yttrium oxide, europium oxide, and sulfur. The method employs high-energy ball milling to enable a substitution reaction between oxygen and sulfur, unlike conventional methods, such as heating in a sulfurizing atmosphere. It was found that the material is fluorescent through X-ray irradiation, and the luminescence spectra exhibit four peaks in the wavelength region from 500 to 800 nm.

40 CFR 721.10011 - Barium calcium manganese strontium oxide.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Barium calcium manganese strontium... Specific Chemical Substances § 721.10011 Barium calcium manganese strontium oxide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as barium calcium...

40 CFR 721.10011 - Barium calcium manganese strontium oxide.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Barium calcium manganese strontium... Specific Chemical Substances § 721.10011 Barium calcium manganese strontium oxide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as barium calcium...

Barium cyanide

Integrated Risk Information System (IRIS)

Barium cyanide ; CASRN 542 - 62 - 1 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Ef

Creating unstable velocity-space distributions with barium injections

NASA Technical Reports Server (NTRS)

Pongratz, M. B.

1983-01-01

Ion velocity-space distributions resulting from barium injections from orbiting spacecraft and shaped charges are discussed. Active experiments confirm that anomalous ionization processes may operate, but photoionization accounts for the production of the bulk of the barium ions. Pitch-angle diffusion and/or velocity-space diffusion may occur, but observations of barium ions moving upwards against gravity suggests that the ions retain a significant enough fraction of their initial perpendicular velocity to provide a mirror force. The barium ion plasmas should have a range of Alfven Mach numbers and plasma betas. Because the initial conditions can be predicted these active experiments should permit testing plasma instability hypotheses.

Do all barium stars have a white dwarf companion?

NASA Technical Reports Server (NTRS)

Dominy, J. F.; Lambert, D. L.

1983-01-01

International Ultraviolet Explorer short-wavelength, low-dispersion spectra were analyzed for four barium, two mild barium, and one R-type carbon star in order to test the hypothesis that the barium and related giants are produced by mass transfer from a companion now present as a white dwarf. An earlier tentative identification of a white dwarf companion to the mild barium star Zeta Cyg is confirmed. For the other stars, no ultraviolet excess attributable to a white dwarf is seen. Limits are set on the bolometric magnitude and age of a possible white dwarf companion. Since the barium stars do not have obvious progenitors among main-sequence and subgiant stars, mass transfer must be presumed to occur when the mass-gaining star is already on the giant branch. This restriction, and the white dwarf's minimum age, which is greater than 8 x 10 to the 8th yr, determined for several stars, effectively eliminates the hypothesis that mass transfer from an asymptotic giant branch star creates a barium star. Speculations are presented on alternative methods of producing a barium star in a binary system.

Barium Stars and Thermohaline Mixing

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

Husti, Laura

2008-01-24

Barium stars are formed in binary systems through mass transfer from the carbon and s-element rich primary in the AGB phase, to the secondary star which is in a less evolved evolutionary stage. The mixing of the accreted material from the AGB donor with the envelope of the secondary results in a dilution of the s-element abundances. Dilution in red giants is explained by the occurence of the first dredge up, while in case of dwarfs thermohaline mixing would determine it. A comparison between the theoretical predictions of the AGB stellar models and the spectroscopical observations of a large samplemore » of barium stars has been made. Dilution due to thermohaline mixing was taken into account when searching for best fits of the observational data. The importance of thermohaline mixing in barium dwarfs is discussed.« less

Design, testing, fabrication and launch support of a liquid chemical barium release payload (utilizing the liquid fluorine-barium salt/hydrazine system)

NASA Technical Reports Server (NTRS)

Stokes, C. S.; Smith, E. W.; Murphy, W. J.

1972-01-01

A payload was designed which included a cryogenic oxidizer tank, a fuel tank, and burner section. Release of 30 lb of chemicals was planned to occur in 2 seconds at the optimum oxidizer to fuel ratio. The chemicals consisted of 17 lb of liquid fluorine oxidizer and 13 lb of hydrazine-barium salt fuel mixture. The fuel mixture was 17% barium chloride, 16% barium nitrate, and 67% hydrazine, and contained 2.6 lb of available barium. Two significant problem areas were resolved during the program: explosive valve development and burner operation. The release payload was flight tested, from Wallops Island, Virginia. The release took place at an altitude of approximately 260 km. The release produced a luminous cloud which expanded very rapidly, disappearing to the human eye in about 20 seconds. Barium ion concentration slowly increased over a wide area of sky until measurements were discontinued at sunrise (about 30 minutes).

Enhancement of Superconductivity of Lanthanum and Yttrium Sesquicarbide

DOEpatents

Krupka, M. C.; Giorgi, A. L.; Krikorian, N. H.; Szklarz, E. G.

1972-06-22

A method of enhancing the superconductivity of body-centered cubic lanthanum and yttrium sesquicarbide through formation of the sesquicarbides from ternary alloys of novel composition (N/sub x/M/sub 1-x/)C/sub z/, where N is yttrium or lanthanum, M is thorium, any of the Group IV and VI transition metals, or gold, germanium or silicon, and z is approximately 1.2 to 1.6. These ternary sesquicarbides have superconducting transition temperatures as high as 17.0/sup 0/K.

Enhancement of superconductivity of lanthanum and yttrium sesquicarbide

DOEpatents

Krupka, M.C.; Giorgi, A.L.; Krikorian, N.H.; Szklarz, E.G.

1971-06-22

A method of enhancing the superconductivity of body-centered cubic lanthanum and yttrium sesquicarbide through formation of the sesquicarbides from ternary alloys of novel composition (N/sub x/M/sub 1-x/)C/sub z/, where N is yttrium or lanthanum, M is thorium, any of the Group IV and VI transition metals, or gold, germanium or silicon, and z is approximately 1.2 to 1.6. These ternary sesquicarbides have superconducting transition temperatures as high as 17.0/sup 0/K.

Evaluation of gastrointestinal tract transit times using barium-impregnated polyethylene spheres and barium sulfate suspension in a domestic pigeon (Columba livia) model.

PubMed

Bloch, Rebecca A; Cronin, Kimberly; Hoover, John P; Pechman, Robert D; Payton, Mark E

2010-03-01

Barium impregnated polyethylene spheres (BIPS) are used in small animal medicine as an alternative to barium sulfate for radiographic studies of the gastrointestinal tract. To determine the usefulness of BIPS as an alternative to barium suspension in measuring gastrointestinal (GI) transit time for avian species, ventrodorsal radiographs were used to follow the passage of BIPS and 30% barium sulfate suspension through the GI tracts of domestic pigeons (Columba livia). Gastrointestinal transit times of thirty 1.5-mm BIPS administered in moistened gelatin capsules and 30% barium sulfate suspension gavaged into the crop were compared in 6 pigeons. Although the barium suspension passed out of the GI tract of all pigeons within 24 hours, the 1.5-mm BIPS remained in the ventriculus for 368.0 +/- 176.8 hours and did not clear the GI tract for 424.0 +/- 204.6 hours. Although the times for passage of BIPS and 30% barium sulfate suspension from the crop into the ventriculus were not significantly different (P = .14), the times for passage of BIPS from the ventriculus into the large intestine-cloaca and for clearance from the GI tract of the pigeons were significantly longer (P < .001) than for the 30% barium sulfate suspension. From the results of this study, we conclude that BIPS are not useful for radiographically evaluating GI transit times in pigeons and are unlikely to be useful in other avian species that have a muscular ventriculus. BIPS may or may not be useful for evaluating GI transit times in species that lack a muscular ventriculus.

Barium Sulfate

MedlinePlus

... and intestine using x-rays or computed tomography (CAT scan, CT scan; a type of body scan that uses a ... be clearly seen by x-ray examination or CT scan. ... more times before an x-ray examination or CT scan.If you are using a barium sulfate enema, ...

Production and characterization of europium doped sol-gel yttrium oxide

NASA Astrophysics Data System (ADS)

Krebs, J. K.; Hobson, Christopher; Silversmith, Ann

2004-03-01

Sol-gel produced materials have recently gained attention for their use in producing nanoscale dielectric materials for confinement studies. Lanthanide impurities in the dielectric enable experimenters to optically probe the structure and dynamic properties of the nanoparticle hosts. We report on an alkoxide sol-gel production method used to produce trivalent europium doped yttrium oxide. Our process follows the standard hydrolysis of an alkoxide precursor with water containing the lanthanide ions. The sol is then aged and calcined at 800 ^oC to produce the powder samples. X-ray diffraction confirms the structure of the powder is that of Y_2O_3. The emission and excitation of the europium impurities is consistent with that of europium doped single crystal yttrium oxide, where it is known that the europium ions substitute for yttrium in the lattice. We therefore conclude that the sol-gel process enables the incorporation of europium ions into the yttrium oxide structure at temperatures far below the melting temperature. The results of preliminary dynamics measurements will also be discussed.

The behaviour of selected yttrium containing bioactive glass microspheres in simulated body environments.

PubMed

Cacaina, D; Ylänen, H; Simon, S; Hupa, M

2008-03-01

The study aims at the manufacture and investigation of biodegradable glass microspheres incorporated with yttrium potentially useful for radionuclide therapy of cancer. The glass microspheres in the SiO2-Na2O-P2O5-CaO-K2O-MgO system containing yttrium were prepared by conventional melting and flame spheroidization. The behaviour of the yttrium silicate glass microspheres was investigated under in vitro conditions using simulated body fluid (SBF) and Tris buffer solution (TBS), for different periods of time, according to half-life time of the Y-90. The local structure of the glasses and the effect of yttrium on the biodegradability process were evaluated by Fourier Transform Infrared (FT-IR) spectroscopy and Back Scattered Electron Imaging of Scanning Electron Microscopy (BEI-SEM) equipped with Energy Dispersive X-ray (EDX) analysis. UV-VIS spectrometry and Inductively Coupled Plasma Mass Spectrometry (ICP-MS) was used for analyzing the release behaviour of silica and yttrium in the two used solutions. The results indicate that the addition of yttrium to a bioactive glass increases its structural stability which therefore, induced a different behaviour of the glasses in simulated body environments.

Electronic structure and electron-phonon interaction in hexagonal yttrium by density functional calculations

NASA Astrophysics Data System (ADS)

Singh, Prabhakar P.

2007-03-01

To understand the pressure-induced changes in the electronic structure and the electron-phonon interaction in yttrium, we have studied hexagonal-close-packed (hcp) yttrium, stable at ambient pressure, and double hexagonal-close-packed (dhcp) yttrium, stable up to around 44GPa , using density-functional-based methods. Our results show that as one goes from hcp yttrium to dhcp yttrium, there are (i) a substantial charge transfer from s→d with extensive modifications of the d band and a sizable reduction in the density of states at the Fermi energy, (ii) a substantial stiffening of phonon modes with the electron-phonon coupling covering the entire frequency range, and (iii) an increase in the electron-phonon coupling constant λ from 0.55 to 1.24, leading to a change in the superconducting transition temperature Tc from 0.3to15.3K for μ*=0.2 .

Alkali metal yttrium neo-pentoxide double alkoxide precursors to alkali metal yttrium oxide nanomaterials

DOE PAGES

Boyle, Timothy J.; Neville, Michael L.; Sears, Jeremiah Matthew; ...

2016-03-15

In this study, a series of alkali metal yttrium neo-pentoxide ([AY(ONep) 4]) compounds were developed as precursors to alkali yttrium oxide (AYO 2) nanomaterials. The reaction of yttrium amide ([Y(NR 2) 3] where R=Si(CH 3) 3) with four equivalents of H-ONep followed by addition of [A(NR 2)] (A=Li, Na, K) or A o (A o=Rb, Cs) led to the formation of a complex series of A nY(ONep) 3+n species, crystallographically identified as [Y 2Li 3(μ 3-ONep)(μ 3-HONep)(μ-ONep) 5(ONep) 3(HONep) 2] (1), [YNa 2(μ 3-ONep) 4(ONep)] 2 (2), {[Y 2K 3(μ 3-ONep) 3(μ-ONep) 4(ONep) 2(ηξ-tol) 2][Y 4K 2(μ 4-O)(μ 3-ONep) 8(ONep)more » 4]•η x-tol]} (3), [Y 4K 2(μ 4-O)(μ 3-ONep) 8(ONep) 4] (3a), [Y 2Rb 3(μ 4-ONep) 3(μ-ONep) 6] (4), and [Y 2Cs 4(μ 6-O)(μ 3-ONep) 6(μ 3-HONep) 2(ONep) 2(η x-tol) 4]•tol (5). Compounds 1–5 were investigated as single source precursors to AYOx nanomaterials following solvothermal routes (pyridine, 185 °C for 24h). The final products after thermal processing were found by powder X-ray diffraction experiments to be Y 2O 3 with variable sized particles based on transmission electron diffraction. Energy dispersive X-ray spectroscopy studies indicated that the heavier alkali metal species were present in the isolated nanomaterials.« less

Evidence of yttrium silicate inclusions in YSZ-porcelain veneers.

PubMed

Stoner, Brian R; Griggs, Jason A; Neidigh, John; Piascik, Jeffrey R

2014-04-01

This report introduces the discovery of crystalline defects that can form in the porcelain veneering layer when in contact with yttria-stabilized zirconia (YSZ). The focus was on dental prostheses and understanding the defects that form in the YSZ/porcelain system; however the data reported herein may have broader implications toward the use and stability of YSZ-based ceramics in general. Specimens were cut from fully sintered YSZ plates and veneering porcelain was applied (<1 mm thick) to one surface and fired under manufacturer's recommended protocol. Scanning electron microscopy (SEM) with integrated electron dispersive X-ray (EDAX) was used for microstructural and elemental analysis. EDAX, for chemical analysis and transmission electron diffraction (TED) for structural analysis were both performed in the transmission electron microscope (TEM). Additionally, in order to spatially resolve Y-rich precipitates, micro-CT scans were conducted at varying depths within the porcelain veneer. Local EDAX (SEM) was performed in the regions of visible inclusions and showed significant increases in yttrium concentration. TEM specimens also showed apparent inclusions in the porcelain and selected area electron diffraction was performed on these regions and found the inclusions to be crystalline and identified as either yttrium-silicate (Y2 SiO5 ) or yttrium-disilicate (Y2 Si2 O7 ). Micro-CT data showed that yttrium-silicate precipitates were distributed throughout the thickness of the porcelain veneer. Future studies are needed to determine whether many of the premature failures associated with this materials system may be the result of crystalline flaws that form as a result of high temperature yttrium diffusion near the surfaces of YSZ. © 2013 Wiley Periodicals, Inc.

Anomalous Electron Spectrum and Its Relation to Peak Structure of Electron Scattering Rate in Cuprate Superconductors

NASA Astrophysics Data System (ADS)

Gao, Deheng; Mou, Yingping; Feng, Shiping

2018-02-01

The recent discovery of a direct link between the sharp peak in the electron quasiparticle scattering rate of cuprate superconductors and the well-known peak-dip-hump structure in the electron quasiparticle excitation spectrum is calling for an explanation. Within the framework of the kinetic-energy-driven superconducting mechanism, the complicated line-shape in the electron quasiparticle excitation spectrum of cuprate superconductors is investigated. It is shown that the interaction between electrons by the exchange of spin excitations generates a notable peak structure in the electron quasiparticle scattering rate around the antinodal and nodal regions. However, this peak structure disappears at the hot spots, which leads to that the striking peak-dip-hump structure is developed around the antinodal and nodal regions, and vanishes at the hot spots. The theory also confirms that the sharp peak observed in the electron quasiparticle scattering rate is directly responsible for the remarkable peak-dip-hump structure in the electron quasiparticle excitation spectrum of cuprate superconductors.

Frequency and Temperature Dependent Dielectric Properties of Free-standing Strontium Titanate Thin Films.

NASA Astrophysics Data System (ADS)

Dalberth, Mark J.; Stauber, Renaud E.; Anderson, Britt; Price, John C.; Rogers, Charles T.

1998-03-01

We will report on the frequency and temperature dependence of the complex dielectric function of free-standing strontium titanate (STO) films. STO is an incipient ferroelectric with electric-field tunable dielectric properties of utility in microwave electronics. The films are grown epitaxially via pulsed laser deposition on a variety of substrates, including lanthanum aluminate (LAO), neodymium gallate (NGO), and STO. An initial film of yttrium barium cuprate (YBCO) is grown on the substrate, followed by deposition of the STO layer. Following deposition, the sacrificial YBCO layer is chemically etched away in dilute nitric acid, leaving the substrate and a released, free-standing STO film. Coplanar capacitor structures fabricated on the released films allow us to measure the dielectric response. We observe a peak dielectric function in excess of 5000 at 35K, change in dielectric constant of over a factor of 8 for 10Volt/micron electric fields, and temperature dependence above 50K that is very similar to bulk material. The dielectric loss shows two peaks, each with a thermally activated behavior, apparently arising from two types of polar defects. We will discuss the correlation between dielectric properties, growth conditions, and strain in the free-standing STO films.

Vestigial nematicity from spin and/or charge order in the cuprates

DOE PAGES

Nie, Laimei; Maharaj, Akash V.; Fradkin, Eduardo; ...

2017-08-01

Nematic order has manifested itself in a variety of materials in the cuprate family. We propose an effective field theory of a layered system with incommensurate, intertwined spin- and charge-density wave (SDW and CDW) orders, each of which consists of two components related by C4 rotations. Using a variational method (which is exact in a large N limit), we study the development of nematicity from partially melting those density waves by either increasing temperature or adding quenched disorder. As temperature decreases we first find a transition to a nematic phase, but depending on the range of parameters (e.g. doping concentration)more » the strongest fluctuations associated with this phase reflect either proximate SDW or CDW order. We also discuss the changes in parameters that can account for the differences in the SDW-CDW interplay between the (214) family and the other hole-doped cuprates.« less

Nematicity in stripe ordered cuprates probed via resonant x-ray scattering

DOE PAGES

Achkar, A. J.; Zwiebler, M.; McMahon, Christopher; ...

2016-02-05

We found that in underdoped cuprate superconductors, a rich competition occurs between superconductivity and charge density wave (CDW) order. Whether rotational symmetry-breaking (nematicity) occurs intrinsically and generically or as a consequence of other orders is under debate. Here, we employ resonant x-ray scattering in stripe-ordered superconductors (La,M) 2CuO 4 to probe the relationship between electronic nematicity of the Cu 3d orbitals, structure of the (La,M) 2O 2 layers, and CDW order. We find distinct temperature dependences for the structure of the (La,M) 2O 2 layers and the electronic nematicity of the CuO 2 planes, with only the latter being enhancedmore » by the onset of CDW order. Our results identify electronic nematicity as an order parameter that is distinct from a purely structural order parameter in underdoped striped cuprates.« less

Nematicity in stripe ordered cuprates probed via resonant x-ray scattering

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

Achkar, A. J.; Zwiebler, M.; McMahon, Christopher

We found that in underdoped cuprate superconductors, a rich competition occurs between superconductivity and charge density wave (CDW) order. Whether rotational symmetry-breaking (nematicity) occurs intrinsically and generically or as a consequence of other orders is under debate. Here, we employ resonant x-ray scattering in stripe-ordered superconductors (La,M) 2CuO 4 to probe the relationship between electronic nematicity of the Cu 3d orbitals, structure of the (La,M) 2O 2 layers, and CDW order. We find distinct temperature dependences for the structure of the (La,M) 2O 2 layers and the electronic nematicity of the CuO 2 planes, with only the latter being enhancedmore » by the onset of CDW order. Our results identify electronic nematicity as an order parameter that is distinct from a purely structural order parameter in underdoped striped cuprates.« less

A high-altitude barium radial injection experiment

NASA Technical Reports Server (NTRS)

Wescott, E. M.; Stenbaek-Nielsen, H. C.; Hallinan, T. J.; Deehr, C. S.; Romick, G. J.; Olson, J. V.; Roederer, J. G.; Sydora, R.

1980-01-01

A rocket launched from Poker Flat, Alaska, carried a new type of high-explosive barium shaped charge to 571 km, where detonation injected a thin disk of barium vapor with high velocity nearly perpendicular to the magnetic field. The TV images of the injection are spectacular, revealing three major regimes of expanding plasma which showed early instabilities in the neutral gas. The most unusual effect of the injection is a peculiar rayed barium-ion structure lying in the injection plane and centered on a 5 km 'black hole' surrounding the injection point. Preliminary electrostatic computer simulations show a similar rayed development.

VizieR Online Data Catalog: Infrared properties of barium stars (Chen+, 2001)

NASA Astrophysics Data System (ADS)

Chen, P. S.

2001-04-01

We present the results of a systematic survey for IRAS associations of barium stars. A total of 155 associations were detected, and IRAS low-resolution spectra exist for 50 barium stars. We use different color-color diagrams from the visual band to 60μm, relations between these colors and the spectral type, the barium intensity, and the IRAS low-resolution spectra to discuss physical properties of barium stars in the infrared. It is confirmed that most barium stars have infrared excesses in the near infrared. However, a new result of this work is that most barium stars have no excesses in the far infrared. This fact may imply that infrared excesses of barium stars are mainly due to the re-emission of energy lost from the Bond-Neff depression. It is also shown that the spectral type and the barium intensity of barium stars are not correlated with infrared colors, but may be correlated with V-K color. (1 data file).

Unified electronic phase diagram for hole-doped high- Tc cuprates

NASA Astrophysics Data System (ADS)

Honma, T.; Hor, P. H.

2008-05-01

We have analyzed various characteristic temperatures and energies of hole-doped high- Tc cuprates as a function of a dimensionless hole-doping concentration (pu) . Entirely based on the experimental grounds, we construct a unified electronic phase diagram (UEPD), where three characteristic temperatures ( T∗ ’s) and their corresponding energies ( E∗ ’s) converge as pu increases in the underdoped regime. T∗ ’s and E∗ ’s merge together with the Tc curve and 3.5kBTc curve at pu˜1.1 in the overdoped regime, respectively. They finally go to zero at pu˜1.3 . The UEPD follows an asymmetric half-dome-shaped Tc curve, in which Tc appears at pu˜0.4 , reaches a maximum at pu˜1 , and rapidly goes to zero at pu˜1.3 . The asymmetric half-dome-shaped Tc curve is at odds with the well-known symmetric superconducting dome for La2-xSrxCuO4 (SrD-La214), in which two characteristic temperatures and energies converge as pu increases and merge together at pu˜1.6 , where Tc goes to zero. The UEPD clearly shows that pseudogap phase precedes and coexists with high temperature superconductivity in the underdoped and overdoped regimes, respectively. It is also clearly seen that the upper limit of high- Tc cuprate physics ends at a hole concentration that equals to 1.3 times the optimal doping concentration for almost all high- Tc cuprate materials and 1.6 times the optimal doping concentration for the SrD-La214. Our analysis strongly suggests that pseudogap is a precursor of high- Tc superconductivity, the observed quantum critical point inside the superconducting dome may be related to the end point of UEPD, and the normal state of the underdoped and overdoped high temperature superconductors cannot be regarded as a conventional Fermi liquid phase.

Dimensional Crossover of Charge-Density Wave Correlations in the Cuprates

NASA Astrophysics Data System (ADS)

Caplan, Yosef; Orgad, Dror

2017-09-01

Short-range charge-density wave correlations are ubiquitous in underdoped cuprates. They are largely confined to the copper-oxygen planes and typically oscillate out of phase from one unit cell to the next in the c direction. Recently, it was found that a considerably longer-range charge-density wave order develops in YBa2 Cu3 O6 +x above a sharply defined crossover magnetic field. This order is more three-dimensional and is in-phase along the c axis. Here, we show that such behavior is a consequence of the conflicting ordering tendencies induced by the disorder potential and the Coulomb interaction, where the magnetic field acts to tip the scales from the former to the latter. We base our conclusion on analytic large-N analysis and Monte Carlo simulations of a nonlinear sigma model of competing superconducting and charge-density wave orders. Our results are in agreement with the observed phenomenology in the cuprates, and we discuss their implications to other members of this family, which have not been measured yet at high magnetic fields.

Yttrium and rare earth stabilized fast reactor metal fuel

DOEpatents

Guon, Jerold; Grantham, LeRoy F.; Specht, Eugene R.

1992-01-01

To increase the operating temperature of a reactor, the melting point and mechanical properties of the fuel must be increased. For an actinide-rich fuel, yttrium, lanthanum and/or rare earth elements can be added, as stabilizers, to uranium and plutonium and/or a mixture of other actinides to raise the melting point of the fuel and improve its mechanical properties. Since only about 1% of the actinide fuel may be yttrium, lanthanum, or a rare earth element, the neutron penalty is low, the reactor core size can be reduced, the fuel can be burned efficiently, reprocessing requirements are reduced, and the nuclear waste disposal volumes reduced. A further advantage occurs when yttrium, lanthanum, and/or other rare earth elements are exposed to radiation in a reactor, they produce only short half life radioisotopes, which reduce nuclear waste disposal problems through much shorter assured-isolation requirements.

On the important role of the anti-Jahn-Teller effect in underdoped cuprate superconductors

NASA Astrophysics Data System (ADS)

Kamimura, Hiroshi; Matsuno, Shunichi; Mizokawa, Takashi; Sasaoka, Kenji; Shiraishi, Kenji; Ushio, Hideki

2013-04-01

In this paper it is shown that the "anti-Jahn-Teller effect" plays an essential role in giving rise to a small Fermi surface of Fermi pockets above Tc and d-wave superconductivity below Tc in underdoped cuprates. In the first part of the present paper, we review the latest developments of the model proposed by Kamimura and Suwa, which bears important characteristics born from the interplay of Jahn-Teller Physics and Mott Physics. It is shown that the feature of Fermi surfaces in underdoped LSCO is the Fermi pockets in the nodal region constructed by doped holes under the coexistence of a metallic state and of the local antiferromagnetic order. In the antinodal region in the momentum space, there are no Fermi surfaces. Then it is discussed that the phonon-involved mechanism based on the Kamimura-Suwa model leads to the d-wave superconductivity. In particular, it is shown that the origin of strong electron-phonon interactions in cuprates is due to the anti-Jahn-Teller effect. In the second part a recent theoretical result on the energy distribution curves (EDCs) of angle-resolved photoemission spectroscopy (ARPES) below Tc is discussed. It is shown that the feature of ARPES profiles of underdoped cuprates consists of a coherent peak in the nodal region and the real transitions of photoexcited electrons from occupied states below the Fermi level to a free-electron state above the vacuum level in the antinodal region, where the latter transitions form a broad hump. From this feature, the origin of the two distinct gaps observed by ARPES is elucidated without introducing the concept of the pseudogap. Finally, a remark is made on the phase diagram of underdoped cuprates.

Surface studies of barium and barium oxide on tungsten and its application to understanding the mechanism of operation of an impregnated tungsten cathode

NASA Technical Reports Server (NTRS)

Forman, R.

1976-01-01

Surface studies have been made of multilayer and monolayer films of barium and barium oxide on a tungsten substrate. The purpose of the investigation was to synthesize the surface conditions that exist on an activated impregnated tungsten cathode and obtain a better understanding of the mechanism of operation of such cathodes. The techniques employed in these measurements were Auger spectroscopy and work-function measurements. The results of this study show that the surface of an impregnated cathode is identical to that observed for a synthesized monolayer or partial monolayer of barium on oxidized tungsten by evaluating Auger spectra and work-function measurements. Data obtained from desorption studies of barium monolayers on a tungsten substrate in conjunction with Auger and work-function results have been interpreted to show that throughout most of its life an impreganated cathode has a partial monolayer, rather than a monolayer, of barium on its surface.

Effects of chemesthetic stimuli mixtures with barium on swallowing apnea duration.

PubMed

Todd, J Tee; Butler, Susan G; Plonk, Drew P; Grace-Martin, Karen; Pelletier, Cathy A

2012-10-01

This study tested the hypotheses that swallowing apnea duration (SAD) will increase given barium versus water, chemesthetic stimuli (i.e., water < ethanol, acid, and carbonation) mixed with barium, age (older > younger), and genetic taste differences (supertasters > nontasters). Prospective group design. University Medical Center. Eighty healthy women were identified as nontasters and supertasters, equally comprising two age groups: 18 to 35 years and 60+ years. The KayPentax Swallowing Signals Lab was used to acquire SAD via nasal cannula during individually randomized swallows of 5 mL barium, 2.7% w/v citric acid with barium, carbonation with barium, and 50:50 diluted ethanol with barium. Data were analyzed using path analysis, with the mediator of chemesthetic perception, adjusted for repeated measures. Significant main effects of age (P = .012) and chemesthetic stimuli (P = .014) were found, as well as a significant interaction between chemesthetic stimuli and age (P = .028). Older women had a significantly longer SAD than younger women. Post hoc analyses revealed that barium mixed with ethanol elicited a significantly longer SAD than other bolus conditions, regardless of age group. There were no significant differences in SAD between barium and water conditions, and no significant effect of chemesthetic perception (P > .05). Ethanol added to barium elicited longer SAD compared to plain barium, but not the other chemesthetic conditions. Older women had a longer SAD than younger women in all conditions. These findings may influence design of future studies examining effects of various stimuli on SAD. Copyright © 2012 The American Laryngological, Rhinological, and Otological Society, Inc.

Tungsten and Barium Transport in the Internal Plasma of Hollow Cathodes

NASA Technical Reports Server (NTRS)

Polk, James E.; Mikellides, Ioannis G.; Katz, Ira; Capece, Angela M.

2008-01-01

The effect of tungsten erosion, transport and redeposition on the operation of dispenser hollow cathodes was investigated in detailed examinations of the discharge cathode inserts from an 8200 hour and a 30,352 hour ion engine wear test. Erosion and subsequent re-deposition of tungsten in the electron emission zone at the downstream end of the insert reduces the porosity of the tungsten matrix, preventing the flow of barium from the interior. This inhibits the interfacial reactions of the barium-calcium-aluminate impregnant with the tungsten in the pores. A numerical model of barium transport in the internal xenon discharge plasma shows that the barium required to reduce the work function in the emission zone can be supplied from upstream through the gas phase. Barium that flows out of the pores of the tungsten insert is rapidly ionized in the xenon discharge and pushedback to the emitter surface by the electric field and drag from the xenon ion flow. Thisbarium ion flux is sufficient to maintain a barium surface coverage at the downstream endgreater than 0.6, even if local barium production at that point is inhibited by tungsten deposits. The model also shows that the neutral barium pressure exceeds the equilibrium vapor pressure of the impregnant decomposition reaction over much of the insert length,so the reactions are suppressed. Only a small region upstream of the zone blocked by tungsten deposits is active and supplies the required barium. These results indicate that hollowcathode failure models based on barium depletion rates in vacuum dispenser cathodes are very conservative.

Barium Stars: Theoretical Interpretation

NASA Astrophysics Data System (ADS)

Husti, Laura; Gallino, Roberto; Bisterzo, Sara; Straniero, Oscar; Cristallo, Sergio

2009-09-01

Barium stars are extrinsic Asymptotic Giant Branch (AGB) stars. They present the s-enhancement characteristic for AGB and post-AGB stars, but are in an earlier evolutionary stage (main sequence dwarfs, subgiants, red giants). They are believed to form in binary systems, where a more massive companion evolved faster, produced the s-elements during its AGB phase, polluted the present barium star through stellar winds and became a white dwarf. The samples of barium stars of Allen & Barbuy (2006) and of Smiljanic et al. (2007) are analysed here. Spectra of both samples were obtained at high-resolution and high S/N. We compare these observations with AGB nucleosynthesis models using different initial masses and a spread of 13C-pocket efficiencies. Once a consistent solution is found for the whole elemental distribution of abundances, a proper dilution factor is applied. This dilution is explained by the fact that the s-rich material transferred from the AGB to the nowadays observed stars is mixed with the envelope of the accretor. We also analyse the mass transfer process, and obtain the wind velocity for giants and subgiants with known orbital period. We find evidence that thermohaline mixing is acting inside main sequence dwarfs and we present a method for estimating its depth.

Recovery of yttrium from fluorescent powder of cathode ray tube, CRT: Zn removal by sulphide precipitation

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

Innocenzi, Valentina, E-mail: valentina.innocenzi1@univaq.it; De Michelis, Ida; Ferella, Francesco

2013-11-15

Highlights: • Treatment of fluorescent powder of CRT waste. • Factorial experimental designs to study acid leaching of fluorescent powder and the purification of leach liquors. • Recover of yttrium by precipitation using oxalic acid. • Suitable flowsheet to recover yttrium from fluorescent powder. - Abstract: This work is focused on the recovery of yttrium and zinc from fluorescent powder of cathode ray tube (CRT). Metals are extracted by sulphuric acid in the presence of hydrogen peroxide. Leaching tests are carried out according to a 2{sup 2} full factorial plan and the highest extraction yields for yttrium and zinc equalmore » to 100% are observed under the following conditions: 3 M of sulphuric acid, 10% v/v of H{sub 2}O{sub 2} concentrated solution at 30% v/v, 10% w/w pulp density, 70 °C and 3 h of reaction. Two series of precipitation tests for zinc are carried out: a 2{sup 2} full factorial design and a completely randomized factorial design. In these series the factors investigated are pH of solution during the precipitation and the amount of sodium sulphide added to precipitate zinc sulphide. The data of these tests are used to describe two empirical mathematical models for zinc and yttrium precipitation yields by regression analysis. The highest precipitation yields for zinc are obtained under the following conditions: pH equal to 2–2.5% and 10–12% v/v of Na{sub 2}S concentrated solution at 10% w/v. In these conditions the coprecipitation of yttrium is of 15–20%. Finally further yttrium precipitation experiments by oxalic acid on the residual solutions, after removing of zinc, show that yttrium could be recovered and calcined to obtain the final product as yttrium oxide. The achieved results allow to propose a CRT recycling process based on leaching of fluorescent powder from cathode ray tube and recovery of yttrium oxide after removing of zinc by precipitation. The final recovery of yttrium is 75–80%.« less

Effect of barium on diffusion of sodium in borosilicate glass.

PubMed

Mishra, R K; Kumar, Sumit; Tomar, B S; Tyagi, A K; Kaushik, C P; Raj, Kanwar; Manchanda, V K

2008-08-15

Diffusion coefficients of sodium in barium borosilicate glasses having varying concentration of barium were determined by heterogeneous isotopic exchange method using (24)Na as the radiotracer for sodium. The measurements were carried out at various temperatures (748-798 K) to obtain the activation energy (E(a)) of diffusion. The E(a) values were found to increase with increasing barium content of the glass, indicating that introduction of barium in the borosilicate glass hinders the diffusion of alkali metal ions from the glass matrix. The results have been explained in terms of the electrostatic and structural factors, with the increasing barium concentration resulting in population of low energy sites by Na(+) ions and, plausibly, formation of more tight glass network. The leach rate measurements on the glass samples show similar trend.

21 CFR 201.304 - Tannic acid and barium enema preparations.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 4 2012-04-01 2012-04-01 false Tannic acid and barium enema preparations. 201.304... Tannic acid and barium enema preparations. (a) It has become a widespread practice for tannic acid to be added to barium enemas to improve X-ray pictures. Tannic acid is capable of causing diminished liver...

21 CFR 201.304 - Tannic acid and barium enema preparations.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 4 2013-04-01 2013-04-01 false Tannic acid and barium enema preparations. 201.304... Tannic acid and barium enema preparations. (a) It has become a widespread practice for tannic acid to be added to barium enemas to improve X-ray pictures. Tannic acid is capable of causing diminished liver...

21 CFR 201.304 - Tannic acid and barium enema preparations.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 4 2014-04-01 2014-04-01 false Tannic acid and barium enema preparations. 201.304... Tannic acid and barium enema preparations. (a) It has become a widespread practice for tannic acid to be added to barium enemas to improve X-ray pictures. Tannic acid is capable of causing diminished liver...

NMR studies of spin dynamics in cuprates

NASA Astrophysics Data System (ADS)

Takigawa, M.; Mitzi, D. B.

1994-04-01

We report recent NMR results in cuprates. The oxygen Knight shift and the Cu nuclear spin-lattice relaxation rate in Bi2.1Sr1.94Ca0.88Cu2.07O8+δ single crystals revealed a gapless superconducting state, which can be most naturally explained by a d-wave pairing state and the intrinsic disorder in this material. The Cu nuclear spin-spin relaxation rate in underdoped YBa2Cu3O6.63 shows distinct temperature dependence from the spin-lattice relaxation rate, providing direct evidence for a pseudo spin-gap near the antiferromagnetic wave vector.

Barium Depletion in the NSTAR Discharge Cathode After 30,000 Hours of Operation

NASA Technical Reports Server (NTRS)

Polk, James E.; Capece, Angela M.; Mikellides, Ioannis G.; Katz, Ira

2010-01-01

Dispenser hollow cathodes rely on a consumable supply of barium released by impregnant materials in the pores of a tungsten matrix to maintain a low work function surface. Examinations of cathode inserts from long duration ion engine tests show deposits of tungsten at the downstream end that appear to block the flow of barium from the interior. In addition, a numerical model of barium transport in the insert plasma indicates that the barium partial pressure in the insert may exceed the equilibrium vapor pressure of the dominant barium-producing reaction, and it was postulated previously that this would suppress barium loss in the upstream part of the insert. New measurements of the depth of barium depletion from a cathode insert operated for 30,352 hours reveal that barium loss is confined to a narrow region near the downstream end, confirming this hypothesis.

Evaluation of barium hydroxide treatment efficacy on a dolomitic marble.

PubMed

Toniolo, L; Colombo, C; Realini, M; Peraio, A; Positano, M

2001-01-01

The Arch of Peace, by Luigi Cagnola, is one of the most famous neoclassical monuments in Milan. It has been subjected to conservative intervention in 1998. In the present paper the efficacy of the consolidation by means of barium hydroxide has been evaluated. The stone material showed severe degradation phenomena as: erosion, pulverisation, exfoliation. The analytical data acquired through X-ray diffraction (XRD), infrared spectrophotometry (FTIR) and scanning electron microscopy (SEM-EDX), allowed to compare the conditions of stone before and after the treatment with barium hydroxide. The presence of barium has been put in evidence mainly on the surface as barium sulphate, whereas barium is only sporadically present within the thickness of the decayed material. The treatment was judged not satisfying and its inefficacy is, most probably, due to a not suitable cleaning procedure carried out before the consolidation.

Competing quantum orderings in cuprate superconductors: A minimal model

NASA Astrophysics Data System (ADS)

Martin, I.; Ortiz, G.; Balatsky, A. V.; Bishop, A. R.

2001-02-01

We present a minimal model for cuprate superconductors. At the unrestricted mean-field level, the model produces homogeneous superconductivity at large doping, striped superconductivity in the underdoped regime and various antiferromagnetic phases at low doping and for high temperatures. On the underdoped side, the superconductor is intrinsically inhomogeneous and global phase coherence is achieved through Josephson-like coupling of the superconducting stripes. The model is applied to calculate experimentally measurable ARPES spectra.

Recovery of yttrium from cathode ray tubes and lamps’ fluorescent powders: experimental results and economic simulation

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

Innocenzi, V., E-mail: valentina.innocenzi1@univaq.it; De Michelis, I.; Ferella, F.

2013-11-15

Highlights: • Fluorescent powder of lamps. • Fluorescent powder of cathode ray rubes. • Recovery of yttrium from fluorescent powders. • Economic simulation for the processes to recover yttrium from WEEE. - Abstract: In this paper, yttrium recovery from fluorescent powder of lamps and cathode ray tubes (CRTs) is described. The process for treating these materials includes the following: (a) acid leaching, (b) purification of the leach liquors using sodium hydroxide and sodium sulfide, (c) precipitation of yttrium using oxalic acid, and (d) calcinations of oxalates for production of yttrium oxides. Experimental results have shown that process conditions necessary tomore » purify the solutions and recover yttrium strongly depend on composition of the leach liquor, in other words, whether the powder comes from treatment of CRTs or lamp. In the optimal experimental conditions, the recoveries of yttrium oxide are about 95%, 55%, and 65% for CRT, lamps, and CRT/lamp mixture (called MIX) powders, respectively. The lower yields obtained during treatments of MIX and lamp powders are probably due to the co-precipitation of yttrium together with other metals contained in the lamps powder only. Yttrium loss can be reduced to minimum changing the experimental conditions with respect to the case of the CRT process. In any case, the purity of final products from CRT, lamps, and MIX is greater than 95%. Moreover, the possibility to treat simultaneously both CRT and lamp powders is very important and interesting from an industrial point of view since it could be possible to run a single plant treating fluorescent powder coming from two different electronic wastes.« less

Barium and Compounds

Integrated Risk Information System (IRIS)

EPA / 635 / R - 05 / 001 www.epa.gov / iris TOXICOLOGICAL REVIEW OF BARIUM AND COMPOUNDS ( CAS No . 7440 - 39 - 3 ) In Support of Summary Information on the Integrated Risk Information System ( IRIS ) March 1998 Minor revisions January 1999 Reference dose revised June 2005 U.S . Environmental Protec

The effect of barium on perceptions of taste intensity and palatability.

PubMed

Dietsch, Angela M; Solomon, Nancy Pearl; Steele, Catriona M; Pelletier, Cathy A

2014-02-01

Barium may affect the perception of taste intensity and palatability. Such differences are important considerations in the selection of dysphagia assessment strategies and interpretation of results. Eighty healthy women grouped by age (younger, older) and genetic taste status (supertaster, nontaster) rated intensity and palatability for seven tastants prepared in deionized water with and without 40 % w/v barium: noncarbonated and carbonated water, diluted ethanol, and high concentrations of citric acid (sour), sodium chloride (salty), caffeine (bitter), and sucrose (sweet). Mixed-model analyses explored the effects of barium, taster status, and age on perceived taste intensity and acceptability of stimuli. Barium was associated with lower taste intensity ratings for sweet, salty, and bitter tastants, higher taste intensity in carbonated water, and lower palatability in water, sweet, sour, and carbonated water. Older subjects reported lower palatability (all barium samples, sour) and higher taste intensity scores (ethanol, sweet, sour) compared to younger subjects. Supertasters reported higher taste intensity (ethanol, sweet, sour, salty, bitter) and lower palatability (ethanol, salty, bitter) than nontasters. Refusal rates were highest for younger subjects and supertasters, and for barium (regardless of tastant), bitter, and ethanol. Barium suppressed the perceived intensity of some tastes and reduced palatability. These effects are more pronounced in older subjects and supertasters, but younger supertasters are least likely to tolerate trials of barium and strong tastant solutions.

SEPARATION OF BARIUM VALUES FROM URANYL NITRATE SOLUTIONS

DOEpatents

Tompkins, E.R.

1959-02-24

The separation of radioactive barium values from a uranyl nitrate solution of neutron-irradiated uranium is described. The 10 to 20% uranyl nitrate solution is passed through a flrst column of a cation exchange resin under conditions favoring the adsorption of barium and certain other cations. The loaded resin is first washed with dilute sulfuric acid to remove a portion of the other cations, and then wash with a citric acid solution at pH of 5 to 7 to recover the barium along with a lesser amount of the other cations. The PH of the resulting eluate is adjusted to about 2.3 to 3.5 and diluted prior to passing through a smaller second column of exchange resin. The loaded resin is first washed with a citric acid solution at a pH of 3 to elute undesired cations and then with citric acid solution at a pH of 6 to eluts the barium, which is substantially free of undesired cations.

Calculated emission rates for barium releases in space

NASA Technical Reports Server (NTRS)

Stenbaek-Nielsen, H. C.

1989-01-01

The optical emissions from barium releases in space are caused by resonance and fluorescent scattering of sunlight. Emission rates for the dominant ion and neutral lines are calculated assuming the release to be optically thin and the barium to be in radiative equilibrium with the solar radiation. The solar spectrum has deep Fraunhofer absorption lines at the primary barium ion resonances. A velocity component toward or away from the sun will Doppler shift the emission lines relative to the absorption lines and the emission rates will increase many-fold over the rest value. The Doppler brightening is important in shaped charge or satellite releases where the barium is injected at high velocities. Emission rates as a function of velocity are calculated for the 4554, 4934, 5854, 6142 and 6497 A ion emission lines and the dominant neutral line at 5535 A. Results are presented for injection parallel to the ambient magnetic field, B, and for injection at an angle to B.

Inverse correlation between quasiparticle mass and Tc in a cuprate high-Tc superconductor

PubMed Central

Putzke, Carsten; Malone, Liam; Badoux, Sven; Vignolle, Baptiste; Vignolles, David; Tabis, Wojciech; Walmsley, Philip; Bird, Matthew; Hussey, Nigel E.; Proust, Cyril; Carrington, Antony

2016-01-01

Close to a zero-temperature transition between ordered and disordered electronic phases, quantum fluctuations can lead to a strong enhancement of electron mass and to the emergence of competing phases such as superconductivity. A correlation between the existence of such a quantum phase transition and superconductivity is quite well established in some heavy fermion and iron-based superconductors, and there have been suggestions that high-temperature superconductivity in copper-oxide materials (cuprates) may also be driven by the same mechanism. Close to optimal doping, where the superconducting transition temperature Tc is maximal in cuprates, two different phases are known to compete with superconductivity: a poorly understood pseudogap phase and a charge-ordered phase. Recent experiments have shown a strong increase in quasiparticle mass m* in the cuprate YBa2Cu3O7-δ as optimal doping is approached, suggesting that quantum fluctuations of the charge-ordered phase may be responsible for the high-Tc superconductivity. We have tested the robustness of this correlation between m* and Tc by performing quantum oscillation studies on the stoichiometric compound YBa2Cu4O8 under hydrostatic pressure. In contrast to the results for YBa2Cu3O7-δ, we find that in YBa2Cu4O8, the mass decreases as Tc increases under pressure. This inverse correlation between m* and Tc suggests that quantum fluctuations of the charge order enhance m* but do not enhance Tc. PMID:27034989

Effectiveness of therapeutic barium enema for diverticular hemorrhage

PubMed Central

Matsuura, Mizue; Inamori, Masahiko; Nakajima, Atsushi; Komiya, Yasuhiko; Inoh, Yumi; Kawasima, Keigo; Naitoh, Mai; Fujita, Yuji; Eduka, Akiko; Kanazawa, Noriyoshi; Uchiyama, Shiori; Tani, Rie; Kawana, Kennichi; Ohtani, Setsuya; Nagase, Hajime

2015-01-01

AIM: To evaluate the effectiveness of barium impaction therapy for patients with colonic diverticular bleeding. METHODS: We reviewed the clinical charts of patients in whom therapeutic barium enema was performed for the control of diverticular bleeding between August 2010 and March 2012 at Yokohama Rosai Hospital. Twenty patients were included in the review, consisting of 14 men and 6 women. The median age of the patients was 73.5 years. The duration of the follow-up period ranged from 1 to 19 mo (median: 9.8 mo). Among the 20 patients were 11 patients who required the procedure for re-bleeding during hospitalization, 6 patients who required it for re-bleeding that developed after the patient left the hospital, and 3 patients who required the procedure for the prevention of re-bleeding. Barium (concentration: 150 w%/v%) was administered per the rectum, and the leading edge of the contrast medium was followed up to the cecum by fluoroscopy. After confirmation that the ascending colon and cecum were filled with barium, the enema tube was withdrawn, and the patient’s position was changed every 20 min for 3 h. RESULTS: Twelve patients remained free of re-bleeding during the follow-up period (range: 1-19 mo) after the therapeutic barium enema, including 9 men and 3 women with a median age of 72.0 years. Re-bleeding occurred in 8 patients including 5 men and 3 women with a median age of 68.5 years: 4 developed early re-bleeding, defined as re-bleeding that occurs within one week after the procedure, and the remaining 4 developed late re-bleeding. The DFI (disease-free interval) decreased 0.4 for 12 mo. Only one patient developed a complication from therapeutic barium enema (colonic perforation). CONCLUSION: Therapeutic barium enema is effective for the control of diverticular hemorrhage in cases where the active bleeding site cannot be identified by colonoscopy. PMID:25987779

Fatal barium chloride poisoning: four cases report and literature review.

PubMed

Ananda, Sunnassee; Shaohua, Zhu; Liang, Liu

2013-06-01

Barium is an alkaline earth metal which has a variety of uses including in the manufacturing industry and in medicine. However, adverse health effects and fatalities occur due to absorption of soluble barium compounds, notably the chloride, nitrate, and hydroxide, which are toxic to humans. Although rare, accidental and suicidal modes of poisoning are sporadically reported in the literature.We describe 4 cases of poisoning due to barium chloride in China. In witnessed cases, severe gastrointestinal symptoms, hypokalemia leading to muscle weakness, cardiac arrhythmias, and respiratory failure were noted. Autopsy showed some nonspecific but common findings, such as subendocardial hemorrhage in the ventricles, visceral petechiae, and fatty changes in the liver. Interestingly, microscopic examination showed degenerative changes and amorphous, flocculent foamy materials in the renal tubules. Toxicology was relevant for barium in blood and tissues. Three of the cases were accidental and 1 homicidal in nature. A round-up of relevant literature on fatal barium compounds poisoning is also provided. Forensic pathologists should be aware of the clinical presentations of barium compound poisoning and especially look for any evidence of hypokalemia. Still, postmortem toxicological and histological studies are essential for an accurate identification of the cause of death.

Exposure to low-dose barium by drinking water causes hearing loss in mice.

PubMed

Ohgami, Nobutaka; Hori, Sohjiro; Ohgami, Kyoko; Tamura, Haruka; Tsuzuki, Toyonori; Ohnuma, Shoko; Kato, Masashi

2012-10-01

We continuously ingest barium as a general element by drinking water and foods in our daily life. Exposure to high-dose barium (>100mg/kg/day) has been shown to cause physiological impairments. Direct administration of barium to inner ears by vascular perfusion has been shown to cause physiological impairments in inner ears. However, the toxic influence of oral exposure to low-dose barium on hearing levels has not been clarified in vivo. We analyzed the toxic influence of oral exposure to low-dose barium on hearing levels and inner ears in mice. We orally administered barium at low doses of 0.14 and 1.4 mg/kg/day to wild-type ICR mice by drinking water. The doses are equivalent to and 10-fold higher than the limit level (0.7 mg/l) of WHO health-based guidelines for drinking water, respectively. After 2-week exposure, hearing levels were measured by auditory brain stem responses and inner ears were morphologically analyzed. After 2-month exposure, tissue distribution of barium was measured by inductively coupled plasma mass spectrometry. Low-dose barium in drinking water caused severe hearing loss in mice. Inner ears including inner and outer hair cells, stria vascularis and spiral ganglion neurons showed severe degeneration. The Barium-administered group showed significantly higher levels of barium in inner ears than those in the control group, while barium levels in bone did not show a significant difference between the two groups. Barium levels in other tissues including the cerebrum, cerebellum, heart, liver and kidney were undetectably low in both groups. Our results demonstrate for the first time that low-dose barium administered by drinking water specifically distributes to inner ears resulting in severe ototoxicity with degeneration of inner ears in mice. Copyright © 2012 Elsevier Inc. All rights reserved.

FOURTH ANNUAL REPORT ON DISTRIBUTION STUDIES BETWEEN MELTS AND SOLID PHASES USING RADIOACTIVE TRACERS

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

Ward, R.; Orr, W.C.; Katz, L.

Cerium(III) ion in a barium chloride flux does not readily exchangs with any of the ions in solid BaZrO/sub 3/ or BaTiO/sub 3/. It reacts to form new solid phases, which are identified, and does not enter the original crystal lattices at an appreciable rate. The strontium was found to exchange at a measurable rate with barium in BaTiO/sub 3/ and with the corresponding ions in alkaline-earth zirconates. Results of a series of equilibrium and rate measurements were interpreted to ahow that the exchange produces an additional solid phase, SrTiO/sub 3/, rather than the mixed phase, or solid solution, thatmore » ndght have been expected. The significance of this observation is discussed. The self-exchange of yttnium ions between a solid compound of yttrium and an alkali chloride flux in which yttrium chloride is dissolved appears in the systems studied to depend primaaily on the solubility of the solid. Exchange is rapid and complete in the case of yttrium oxychlonide, which is soluble to the extent of 0.6%, but is limited to the surface of yttrium chromium oxide, which has no measurable solubility in the flux. The introduction of yttrium ion vacancies in the lattice of yttrium chromium oxide has no detectable effect in promoting exchange. (For preceding period see NYO-3279.) (auth)« less

Sponge-associated bacteria mineralize arsenic and barium on intracellular vesicles

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

Keren, Ray; Mayzel, Boaz; Lavy, Adi

Arsenic and barium are ubiquitous environmental toxins that accumulate in higher trophic-level organisms. Whereas metazoans have detoxifying organs to cope with toxic metals, sponges lack organs but harbour a symbiotic microbiome performing various functions. Here we examine the potential roles of microorganisms in arsenic and barium cycles in the sponge Theonella swinhoei, known to accumulate high levels of these metals. We show that a single sponge symbiotic bacterium, Entotheonella sp., constitutes the arsenic- and barium-accumulating entity within the host. These bacteria mineralize both arsenic and barium on intracellular vesicles. Our results indicate that Entotheonella sp. may act as a detoxifyingmore » organ for its host.« less

Sponge-associated bacteria mineralize arsenic and barium on intracellular vesicles

DOE PAGES

Keren, Ray; Mayzel, Boaz; Lavy, Adi; ...

2017-02-24

Arsenic and barium are ubiquitous environmental toxins that accumulate in higher trophic-level organisms. Whereas metazoans have detoxifying organs to cope with toxic metals, sponges lack organs but harbour a symbiotic microbiome performing various functions. Here we examine the potential roles of microorganisms in arsenic and barium cycles in the sponge Theonella swinhoei, known to accumulate high levels of these metals. We show that a single sponge symbiotic bacterium, Entotheonella sp., constitutes the arsenic- and barium-accumulating entity within the host. These bacteria mineralize both arsenic and barium on intracellular vesicles. Our results indicate that Entotheonella sp. may act as a detoxifyingmore » organ for its host.« less

Barium Titanate Nanoparticles for Biomarker Applications

NASA Astrophysics Data System (ADS)

Matar, O.; Posada, O. M.; Hondow, N. S.; Wälti, C.; Saunders, M.; Murray, C. A.; Brydson, R. M. D.; Milne, S. J.; Brown, A. P.

2015-10-01

A tetragonal crystal structure is required for barium titanate nanoparticles to exhibit the nonlinear optical effect of second harmonic light generation (SHG) for use as a biomarker when illuminated by a near-infrared source. Here we use synchrotron XRD to elucidate the tetragonal phase of commercially purchased tetragonal, cubic and hydrothermally prepared barium titanate (BaTiO3) nanoparticles by peak fitting with reference patterns. The local phase of individual nanoparticles is determined by STEM electron energy loss spectroscopy (EELS), measuring the core-loss O K-edge and the Ti L3-edge energy separation of the t2g, eg peaks. The results show a change in energy separation between the t2g and eg peak from the surface and core of the particles, suggesting an intraparticle phase mixture of the barium titanate nanoparticles. HAADF-STEM and bright field TEM-EDX show cellular uptake of the hydrothermally prepared BaTiO3 nanoparticles, highlighting the potential for application as biomarkers.

Digital modulation of the nickel valence state in a cuprate-nickelate heterostructure

NASA Astrophysics Data System (ADS)

Wrobel, F.; Geisler, B.; Wang, Y.; Christiani, G.; Logvenov, G.; Bluschke, M.; Schierle, E.; van Aken, P. A.; Keimer, B.; Pentcheva, R.; Benckiser, E.

2018-03-01

Layer-by-layer oxide molecular-beam epitaxy has been used to synthesize cuprate-nickelate multilayer structures of composition (La2CuO4)m/LaO /(LaNiO3)n . In a combined experimental and theoretical study, we show that these structures allow a clean separation of dopant and doped layers. Specifically, the LaO layer separating cuprate and nickelate blocks provides an additional charge that, according to density-functional theory calculations, is predominantly accommodated in the interfacial nickelate layers. This is reflected in an elongation of bond distances and changes in valence state, as observed by scanning transmission electron microscopy and x-ray absorption spectroscopy. Moreover, the predicted charge disproportionation in the nickelate interface layers leads to a metal-to-insulator transition when the thickness is reduced to n =2 , as observed in electrical transport measurements. The results exemplify the perspectives of charge transfer in metal-oxide multilayers to induce doping without introducing chemical and structural disorder.

Entropic Origin of Pseudogap Physics and a Mott-Slater Transition in Cuprates

DOE PAGES

Markiewicz, R. S.; Buda, I. G.; Mistark, P.; ...

2017-03-22

Here, we propose a new approach to understand the origin of the pseudogap in the cuprates, in terms of bosonic entropy. The near-simultaneous softening of a large number of different q-bosons yields an extended range of short-range order, wherein the growth of magnetic correlations with decreasing temperature T is anomalously slow. These entropic effects cause the spectral weight associated with the Van Hove singularity (VHS) to shift rapidly and nearly linearly toward half filling at higher T, consistent with a picture of the VHS driving the pseudogap transition at a temperature ~T*. As a byproduct, we develop an order-parameter classificationmore » scheme that predicts supertransitions between families of order parameters. As one example, we find that by tuning the hopping parameters, it is possible to drive the cuprates across a transition between Mott and Slater physics, where a spin-frustrated state emerges at the crossover.« less

Phase separation of electrons strongly coupled with phonons in cuprates and manganites

NASA Astrophysics Data System (ADS)

Alexandrov, Sasha

2009-03-01

Recent advanced Monte Carlo simulations have not found superconductivity and phase separation in the Hubbard model with on-site repulsive electron-electron correlations. I argue that microscopic phase separations in cuprate superconductors and colossal magnetoresistance (CMR) manganites originate from a strong electron-phonon interaction (EPI) combined with unavoidable disorder. Attractive electron correlations, caused by an almost unretarded EPI, are sufficient to overcome the direct inter-site Coulomb repulsion in these charge-transfer Mott-Hubbard insulators, so that low energy physics is that of small polarons and small bipolarons. They form clusters localized by disorder below the mobility edge, but propagate as the Bloch states above the mobility edge. I identify the Froehlich EPI as the most essential for pairing and phase separation in superconducting layered cuprates. The pairing of oxygen holes into heavy bipolarons in the paramagnetic phase (current-carrier density collapse (CCDC)) explains also CMR and high and low-resistance phase coexistence near the ferromagnetic transition of doped manganites.

Freeze cast porous barium titanate for enhanced piezoelectric energy harvesting

NASA Astrophysics Data System (ADS)

Roscow, J. I.; Zhang, Y.; Kraśny, M. J.; Lewis, R. W. C.; Taylor, J.; Bowen, C. R.

2018-06-01

Energy harvesting is an important developing technology for a new generation of self-powered sensor networks. This paper demonstrates the significant improvement in the piezoelectric energy harvesting performance of barium titanate by forming highly aligned porosity using freeze casting. Firstly, a finite element model demonstrating the effect of pore morphology and angle with respect to poling field on the poling behaviour of porous ferroelectrics was developed. A second model was then developed to understand the influence of microstructure-property relationships on the poling behaviour of porous freeze cast ferroelectric materials and their resultant piezoelectric and energy harvesting properties. To compare with model predictions, porous barium titanate was fabricated using freeze casting to form highly aligned microstructures with excellent longitudinal piezoelectric strain coefficients, d 33. The freeze cast barium titanate with 45 vol.% porosity had a d 33  =  134.5 pC N‑1 compared to d 33  =  144.5 pC N‑1 for dense barium titanate. The d 33 coefficients of the freeze cast materials were also higher than materials with uniformly distributed spherical porosity due to improved poling of the aligned microstructures, as predicted by the models. Both model and experimental data indicated that introducing porosity provides a large reduction in the permittivity () of barium titanate, which leads to a substantial increase in energy harvesting figure of merit, , with a maximum of 3.79 pm2 N‑1 for barium titanate with 45 vol.% porosity, compared to only 1.40 pm2 N‑1 for dense barium titanate. Dense and porous barium titanate materials were then used to harvest energy from a mechanical excitation by rectification and storage of the piezoelectric charge on a capacitor. The porous barium titanate charged the capacitor to a voltage of 234 mV compared to 96 mV for the dense material, indicating a 2.4-fold increase that was similar to that

Lack of effect of drinking water barium on cardiovascular risk factors.

PubMed Central

Wones, R G; Stadler, B L; Frohman, L A

1990-01-01

Higher cardiovascular mortality has been associated in a single epidemiological study with higher levels of barium in drinking water. The purpose of this study was to determine whether drinking water barium at levels found in some U.S. communities alters the known risk factors for cardiovascular disease. Eleven healthy men completed a 10-week dose-response protocol in which diet was controlled (600 mg cholesterol; 40% fat, 40% carbohydrate, 20% protein; sodium and potassium controlled at the subject's pre-protocol estimated intake). Other aspects of the subjects' lifestyles known to affect cardiac risk factors were controlled, and the barium content (as barium chloride) of the drinking water (1.5 L/day) was varied from 0 (first 2 weeks), to 5 ppm (next 4 weeks), to 10 ppm (last 4 weeks). Multiple blood and urine samples, morning and evening blood pressure measurements, and 48-hr electrocardiographic monitoring were performed at each dose of barium. There were no changes in morning or evening systolic or diastolic blood pressures, plasma cholesterol or lipoprotein or apolipoprotein levels, serum potassium or glucose levels, or urine catecholamine levels. There were no arrhythmias related to barium exposure detected on continuous electrocardiographic monitoring. A trend was seen toward increased total serum calcium levels with exposure to barium, which was of borderline statistical significance and of doubtful clinical significance. In summary, drinking water barium at levels of 5 and 10 ppm did not appear to affect any of the known modifiable cardiovascular risk factors. PMID:2384067

Towards the design of novel cuprate-based superconductors

NASA Astrophysics Data System (ADS)

Yee, Chuck-Hou

The rapid maturation of materials databases combined with recent development of theories seeking to quantitatively link chemical properties to superconductivity in the cuprates provide the context to design novel superconductors. In this talk, we describe a framework designed to search for new superconductors, which combines chemical rules-of-thumb, insights of transition temperatures from dynamical mean-field theory, first-principles electronic structure tools, materials databases and structure prediction via evolutionary algorithms. We apply the framework to design a family of copper oxysulfides and evaluate the prospects of superconductivity.

Linear dichroism and the nature of charge order in underdoped cuprates

DOE PAGES

Norman, M. R.

2015-04-21

Recent experiments have addressed the nature of the charge order seen in underdoped cuprates. In this paper, I show that x-ray absorption and linear dichroism are excellent probes of such order. Ab initio calculations reveal that a d-wave charge density wave order involving the oxygen ions is a much better description of the data than alternate models.

Two band model for the cuprates

NASA Astrophysics Data System (ADS)

Liu, Shiu; White, Steven

2009-03-01

We use a numerical canonical transformation approach to derive an effective two-band model for the hole-doped cuprates, which keeps both oxygen and copper orbitals but removes double occupancy from each. A similar model was considered previously by Frenkel, Gooding, Shraiman, and Siggia (PRB 41, number 1, page 350). We compare the numerically derived model with previously obtained analytical results. In addition to the usual hopping terms between oxygens tpp and Cu-Cu exchange terms Jdd, the model also includes a strong copper-oxygen exchange interaction Jpd and a Kondo-like spin-flip oxygen-oxygen hopping term Kpdp. We use the density matrix renormalization group to study the charge, spin, and pairing properties of the derived model on ladder systems.

The effect of gap fluctuations on interacting and non-interacting polarization for nano-superconducting grains in electron- and hole-doped cuprates

NASA Astrophysics Data System (ADS)

Afzali, R.; Alizadeh, A.

2017-12-01

The behavior of non-interacting and interacting polarization under influence of fluctuations of the superconducting gap with D-wave symmetry and under consideration of the gap dependence on nano- grain size is obtained in terms of the frequency, temperature and the size at zero and finite temperatures for rectangular cuprate nano-superconducting grains. By using Eliashberg equations and applying the relations of the fermionic dispersion for the hole-doped and electron-doped cuprates, we numerically compute the real part of size-dependent polarization for both types of cuprates. We show that the peak of real part of polarization moves to higher frequency by including the additional fluctuating part of gap (or the nano-size effect). Also, we obtain the temperatures for different frequencies, in which the effect of gap fluctuations fades. In the case of size-dependent gap, there is a critical frequency; for frequencies lower (higher) than the critical frequency, the nano-effect weakens (improves) the superconducting state. Moreover, it is concluded that the real part of polarization for hole- doped cuprates in terms of the grain size has more significant amount in comparison with electron-doped ones.

Superconducting gap in cuprate high temperature superconductors

NASA Astrophysics Data System (ADS)

Verma, Sanjeev K.; Kumari, Anita; Gupta, Anushri; Indu, B. D.

2018-05-01

The many body quantum dynamical evaluation of double time thermodynamic electron Green's functions followed by generalized electron density of states (EDOS) is used to study the superconducting gap (SG). The dependence of EDOS on defects, anharmonicity and electron-phonon interactions makes the problem quite complicated and challenging but furnishes the more realistic grounds to study the SG both in conventional and high temperature superconductors (HTS). For simplicity, only electron-phonon interaction has been taken up to evaluate the intricate integral to enumerate the SG for representative cuprate HTS: YBa2Cu3O7-δ and results show 2Δ/kBTc ⋍ 7.2.

Universal spectral signatures in pnictides and cuprates: the role of quasiparticle-pair coupling.

PubMed

Sacks, William; Mauger, Alain; Noat, Yves

2017-11-08

Understanding the physical properties of a large variety of high-T c superconductors (SC), the cuprate family as well as the more recent iron-based superconductors, is still a major challenge. In particular, these materials exhibit the 'peak-dip-hump' structure in the quasiparticle density of states (DOS). The origin of this structure is explained within our pair-pair interaction (PPI) model: The non-superconducting state consists of incoherent pairs, a 'Cooper-pair glass' which, due to the PPI, undergoes a Bose-like condensation below T c to the coherent SC state. We derive the equations of motion for the quasiparticle operators showing that the DOS 'peak-dip-hump' is caused by the coupling between quasiparticles and excited pair states, or 'super-quasiparticles'. The renormalized SC gap function becomes energy-dependent and non retarded, reproducing accurately the experimental spectra of both pnictides and cuprates, despite the large difference in gap value.

Selective liquid chromatographic separation of yttrium from heavier rare earth elements using acetic acid as a novel eluent.

PubMed

Kifle, Dejene; Wibetoe, Grethe

2013-09-13

One of the major difficulties in the rare earth elements separation is purification of yttrium from heavy rare earth elements. Thus, an HPLC method using acetic acid as novel eluent was explored for selective separation of yttrium form the heavy rare earth elements. When acetic acid is used as a mobile phase yttrium eluted with the lighter lanthanides. This is contrary to its relative position amongst heavier lanthanides when eluents commonly used for separation of rare earth elements were employed. The shift in elution position of yttrium with acetic acid as eluent may reflect a relatively lower stability constant of the yttrium-AcOH complex (in the same order as for the lighter lanthanides) compared to the corresponding AcOH complexes with heavy lanthanides, enabling selective separation of yttrium from the latter. The method was successfully used for selective separation of yttrium in mixed rare earth sample containing about 80% of yttrium and about 20% of heavy rare earth oxides. Thus, the use of AcOH as eluent is an effective approach for separating and determining the trace amounts of heavy rare earth elements in large amounts of yttrium matrix. Separation was performed on C18 column by running appropriate elution programs. The effluent from the column was monitored with diode array detector at absorbance wavelength of 658nm after post column derivatization with Arsenazo III. Copyright © 2013 Elsevier B.V. All rights reserved.

Characterization of Barium Borate Frameworks Using Raman Spectroscopy.

PubMed

Gharavi-Naeini, Jafar; Yoo, Kyung W; Stump, Nathan A

2018-04-01

Systematic micro-Raman scattering investigations have been carried out on Sm +2 doped 2(BaO)-n(B 2 O 3 ) matrices for n = 4, 5, 8, and 2(BaO)-(Na 2 O)-9(B 2 O 3 ) using the 364 nm excitation of an Ar + laser. The Raman results have been compared with the known structures of barium tetraborate, barium pentaborate, barium octaborate, and barium sodium nonaborate. An excellent correlation has been found between the BO 4 /BO 3 composition ratios for each product and intensity ratios of the designated BO 4 and BO 3 Raman peaks. Furthermore, the Raman frequencies of both BO 4 and BO 3 groups undergo a systematic blueshift as n increases from four to nine. The shift results from a decrease of the B-O bond lengths for both BO 4 and BO 3 groups as the samples transition from the tetraborate to nonaborate structures. Linear relations (with negative slopes) have been determined between the measured Raman frequencies and B-O bond lengths in the frameworks.

40 CFR 721.10010 - Barium manganese oxide (BaMnO3).

Code of Federal Regulations, 2011 CFR

2011-07-01

... Substances § 721.10010 Barium manganese oxide (BaMnO3). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as barium manganese oxide (BaMnO3) (PMN P-00... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Barium manganese oxide (BaMnO3). 721...

40 CFR 721.10010 - Barium manganese oxide (BaMnO3).

Code of Federal Regulations, 2010 CFR

2010-07-01

... Substances § 721.10010 Barium manganese oxide (BaMnO3). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as barium manganese oxide (BaMnO3) (PMN P-00... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Barium manganese oxide (BaMnO3). 721...

40 CFR 721.10010 - Barium manganese oxide (BaMnO3).

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Barium manganese oxide (BaMnO3). 721... Substances § 721.10010 Barium manganese oxide (BaMnO3). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as barium manganese oxide (BaMnO3) (PMN P-00...

40 CFR 721.10010 - Barium manganese oxide (BaMnO3).

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Barium manganese oxide (BaMnO3). 721... Substances § 721.10010 Barium manganese oxide (BaMnO3). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as barium manganese oxide (BaMnO3) (PMN P-00...

40 CFR 721.10010 - Barium manganese oxide (BaMnO3).

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Barium manganese oxide (BaMnO3). 721... Substances § 721.10010 Barium manganese oxide (BaMnO3). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as barium manganese oxide (BaMnO3) (PMN P-00...

Silicosis in barium miners.

PubMed Central

Seaton, A; Ruckley, V A; Addison, J; Brown, W R

1986-01-01

Four men who mined barytes in Scotland and who developed pneumoconiosis are described. Three developed progressive massive fibrosis, from which two died; and one developed a nodular simple pneumoconiosis after leaving the industry. The radiological and pathological features of the men's lungs were those of silicosis and high proportions of quartz were found in two of them post mortem. The quartz was inhaled from rocks associated with the barytes in the mines. The features of silicosis in barium miners are contrasted with the benign pneumoconiosis, baritosis, that occurs in workers exposed to crushed and ground insoluble barium salts. Diagnostic difficulties arise when silicosis develops in workers mining minerals known to cause a separate and benign pneumoconiosis. These difficulties are compounded when, as not infrequently happens, the silicotic lesions develop or progress after exposure to quartz has ceased. Images PMID:3787542

Holmium: yttrium aluminum garnet laser-assisted endoscopic sinus surgery: laboratory experience.

PubMed

Shapshay, S M; Rebeiz, E E; Bohigian, R K; Hybels, R L; Aretz, H T; Pankratov, M M

1991-02-01

Endoscopic sinus surgery has gained wide acceptance since its introduction into the United States. Complex sinus anatomy and troublesome bleeding have been associated with complications, which vary in severity from synechia to blindness and leakage of cerebrospinal fluid. Endoscopic sinus surgery using a holmium: yttrium aluminum garnet pulsed solid-state laser oscillating at 2.1 microns with fiberoptic delivery was performed in the laboratory, and the results were compared with those of conventional endoscopic sinus surgery. Three beagle dogs, six human cadaver heads, and one calf head were used in the in vivo and in vitro studies to evaluate the bone ablation, tissue coagulation, and hemostatic properties of the holmium: yttrium aluminum garnet laser. Modified endoscopic telescopes for sinus surgery, a newly developed handpiece for fiberoptic delivery, and other surgical instruments were used. The results indicate that the holmium: yttrium aluminum garnet laser and new delivery instrumentation provide good hemostasis and controlled soft-tissue ablation and bone removal. The access to all sinuses in the human cadaver model was very good. The canine in vivo study showed delayed but complete healing on the laser-treated side. Clinical evaluation of the holmium: yttrium aluminum garnet laser is warranted to increase the precision and safety of endoscopic sinus surgery.

Monte carlo simulations of Yttrium reaction rates in Quinta uranium target

NASA Astrophysics Data System (ADS)

Suchopár, M.; Wagner, V.; Svoboda, O.; Vrzalová, J.; Chudoba, P.; Tichý, P.; Kugler, A.; Adam, J.; Závorka, L.; Baldin, A.; Furman, W.; Kadykov, M.; Khushvaktov, J.; Solnyshkin, A.; Tsoupko-Sitnikov, V.; Tyutyunnikov, S.; Bielewicz, M.; Kilim, S.; Strugalska-Gola, E.; Szuta, M.

2017-03-01

The international collaboration Energy and Transmutation of Radioactive Waste (E&T RAW) performed intensive studies of several simple accelerator-driven system (ADS) setups consisting of lead, uranium and graphite which were irradiated by relativistic proton and deuteron beams in the past years at the Joint Institute for Nuclear Research (JINR) in Dubna, Russia. The most recent setup called Quinta, consisting of natural uranium target-blanket and lead shielding, was irradiated by deuteron beams in the energy range between 1 and 8 GeV in three accelerator runs at JINR Nuclotron in 2011 and 2012 with yttrium samples among others inserted inside the setup to measure the neutron flux in various places. Suitable activation detectors serve as one of possible tools for monitoring of proton and deuteron beams and for measurements of neutron field distribution in ADS studies. Yttrium is one of such suitable materials for monitoring of high energy neutrons. Various threshold reactions can be observed in yttrium samples. The yields of isotopes produced in the samples were determined using the activation method. Monte Carlo simulations of the reaction rates leading to production of different isotopes were performed in the MCNPX transport code and compared with the experimental results obtained from the yttrium samples.

Acute barium intoxication following ingestion of ceramic glaze.

PubMed Central

Thomas, M.; Bowie, D.; Walker, R.

1998-01-01

A case of deliberate overdose of barium sulphide in a psychiatric setting is presented, with resulting flaccid paralysis, malignant arrhythmia, respiratory arrest and severe hypokalaemia, but ultimately with complete recovery. The degree of paralysis appears to be related directly to serum barium levels. The value of early haemodialysis, particularly with respiratory paralysis and hypokalaemia, is emphasised. PMID:10211330

Competing Quantum Orderings in Cuprate Superconductors: A Minimal Model

NASA Astrophysics Data System (ADS)

Martin, Ivar; Ortiz, Gerardo; Balatsky, A. V.; Bishop, A. R.

2001-03-01

We present a minimal model for cuprate superconductors. At the unrestricted mean-field level, the model produces homogeneous superconductivity at large doping, striped superconductivity in the underdoped regime and various antiferromagnetic phases at low doping and for high temperatures. On the underdoped side, the superconductor is intrinsically inhomogeneous and global phase coherence is achieved through Josephson-like coupling of the superconducting stripes. The model is applied to calculate experimentally measurable ARPES spectra, and local density of states measurable by STM.

Compact pulse forming line using barium titanate ceramic material

NASA Astrophysics Data System (ADS)

Kumar Sharma, Surender; Deb, P.; Shukla, R.; Prabaharan, T.; Shyam, A.

2011-11-01

Ceramic material has very high relative permittivity, so compact pulse forming line can be made using these materials. Barium titanate (BaTiO3) has a relative permittivity of 1200 so it is used for making compact pulse forming line (PFL). Barium titanate also has piezoelectric effects so it cracks during high voltages discharges due to stresses developed in it. Barium titanate is mixed with rubber which absorbs the piezoelectric stresses when the PFL is charged and regain its original shape after the discharge. A composite mixture of barium titanate with the neoprene rubber is prepared. The relative permittivity of the composite mixture is measured to be 85. A coaxial pulse forming line of inner diameter 120 mm, outer diameter 240 mm, and length 350 mm is made and the composite mixture of barium titanate and neoprene rubber is filled between the inner and outer cylinders. The PFL is charged up to 120 kV and discharged into 5 Ω load. The voltage pulse of 70 kV, 21 ns is measured across the load. The conventional PFL is made up of oil or plastics dielectrics with the relative permittivity of 2-10 [D. R. Linde, CRC Handbook of Chemistry and Physics, 90th ed. (CRC, 2009); Xia et al., Rev. Sci. Instrum. 79, 086113 (2008); Yang et al., Rev. Sci. Instrum. 81, 43303 (2010)], which increases the length of PFL. We have reported the compactness in length achieved due to increase in relative permittivity of composite mixture by adding barium titanate in neoprene rubber.

Oxygen Annealing in the Synthesis of the Electron-Doped Cuprates

NASA Astrophysics Data System (ADS)

Higgins, J. S.; Bach, P. L.; Yu, W.; Weaver, B. D.; Greene, R. L.

2015-03-01

Post-synthesis oxygen reduction (annealing) in the electron-doped, high-temperature superconducting cuprates is necessary for the establishment of superconductivity. It is not established what effect this reduction has microscopically on the lattice structure. Several mechanisms have been put forth as explanations; they range from disorder minimization1, antiferromagnetic suppression2, and copper migration3. Here we present an electronic transport study on electron-doped cuprate Pr2-xCexCuO4+/-δ (PCCO) thin films in an attempt to better understand the need for this post-synthesis process. Several different cerium doping concentrations of PCCO were grown. Within each doping, a series of films were grown with varying levels of oxygen concentration. As a measure of disorder on the properties of PCCO, several films were irradiated with various doses of 2 MeV protons. Analysis within each series, and among the different dopings, favors disorder minimization through the removal of apical oxygen as the explanation for the necessary post-synthesis annealing process. 1P. K. Mang, et al., Physical Review Letters, 93(2):027002, 2004. 2P. Richard, et al., Physical Review B, 70 (6), 064513, 2004. 3Hye Jung Kang, et al., Nature Materials, 2007. Supported by NSF DMR 1104256.

Bio-based barium alginate film: Preparation, flame retardancy and thermal degradation behavior.

PubMed

Liu, Yun; Zhang, Chuan-Jie; Zhao, Jin-Chao; Guo, Yi; Zhu, Ping; Wang, De-Yi

2016-03-30

A bio-based barium alginate film was prepared via a facile ionic exchange and casting approach. Its flammability, thermal degradation and pyrolysis behaviors, thermal degradation mechanism were studied systemically by limiting oxygen index (LOI), vertical burning (UL-94), microscale combustion calorimetry (MCC), thermogravimetric analysis (TGA) coupled with Fourier transform infrared analysis (FTIR) and pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS). It showed that barium alginate film had much higher LOI value (52.0%) than that of sodium alginate film (24.5%). Moreover, barium alginate film passed the UL-94 V-0 rating, while the sodium alginate film showed no classification. Importantly, peak of heat release rate (PHRR) of barium alginate film in MCC test was much lower than that of sodium alginate film, suggested that introduction of barium ion into alginate film significantly decreased release of combustible gases. TG-FTIR and Py-GC-MS results indicated that barium alginate produced much less flammable products than that of sodium alginate in whole thermal degradation procedure. Finally, a possible degradation mechanism of barium alginate had been proposed. Copyright © 2015 Elsevier Ltd. All rights reserved.

A tale of two metals: contrasting criticalities in the pnictides and hole-doped cuprates

NASA Astrophysics Data System (ADS)

Hussey, N. E.; Buhot, J.; Licciardello, S.

2018-05-01

The iron-based high temperature superconductors share a number of similarities with their copper-based counterparts, such as reduced dimensionality, proximity to states of competing order, and a critical role for 3d electron orbitals. Their respective temperature-doping phase diagrams also contain certain commonalities that have led to claims that the metallic and superconducting (SC) properties of both families are governed by their proximity to a quantum critical point (QCP) located inside the SC dome. In this review, we critically examine these claims and highlight significant differences in the bulk physical properties of both systems. While there is now a large body of evidence supporting the presence of a (magnetic) QCP in the iron pnictides, the situation in the cuprates is much less apparent, at least for the end point of the pseudogap phase. We argue that the opening of the normal state pseudogap in cuprates, so often tied to a putative QCP, arises from a momentum-dependent breakdown of quasiparticle coherence that sets in at much higher doping levels but which is driven by the proximity to the Mott insulating state at half filling. Finally, we present a new scenario for the cuprates in which this loss of quasiparticle integrity and its evolution with momentum, temperature and doping plays a key role in shaping the resultant phase diagram. This key issues review is dedicated to the memory of Dr John Loram whose pioneering measurements, analysis and ideas inspired much of its content.

Synthesis of aluminum-based scandium-yttrium master alloys

NASA Astrophysics Data System (ADS)

Bazhin, V. Yu.; Kosov, Ya. I.; Lobacheva, O. L.; Dzhevaga, N. V.

2015-07-01

The preparation technology for an Al-2% Sc-0.5% Y master alloy using aluminum-manganese alloys has been developed and tested. The microstructure of the prepared master alloy is studied and the compositions of intermetallics is determined. The efficient technological parameters of the synthesis are determined. It is shown that varying the compositions of starting reagents and alloying additions and optimizing the process conditions (temperature, mixing, etc.) allow us to forecast the manufacturing and operating characteristics of aluminum-based master alloys. Joint additions of scandium and yttrium oxides to a charge favor a substantial decrease in the grain size of the formed intermetallics; this effect appears to the utmost in the case of microallying with yttrium up to 0.5 wt %.

The diagnosis of gastro-esophageal reflux disease cannot be made with barium esophagograms.

PubMed

Saleh, C M G; Smout, A J P M; Bredenoord, A J

2015-02-01

For over 50 years, barium studies have been used to diagnose gastro-esophageal reflux disease (GERD), but the value of this test is controversial. Our study aimed to determine if barium esophagograms can be used to diagnose GERD. Barium esophagograms and pH-impedance measurement were performed in 20 subjects with reflux symptoms. pH-impedance measurements were used as gold standard for the diagnosis of GERD. Gastro-esophageal reflux measured with the barium study was defined as a positive outcome. 50% of patients presented gastro-esophageal reflux on the barium esophagogram. No significant differences were observed in acid exposure time between subjects with (median: 7.4%; interquartile range, IQR: 8.4%) or without reflux at barium esophagography (median: 5.95%; IQR: 13.05%; p > 0.05). Nor did we find differences in median proximal extent of reflux measured with impedance monitoring between patients with a positive (median: 6.7%; IQR: 1.95%) and negative barium study (median: 7.1%; IQR: 0.68%; p > 0.05). Patients with reflux on barium esophagogram did not have a positive symptom association probability more often than those who did not have reflux at barium esophagography. Lastly, there were no differences in numbers of acid, weakly acidic or total reflux episodes between those with positive or negative barium esophagogram (p > 0.05). No correlations were found between the maximum proximal extent of gastro-esophageal reflux during esophagography and pH-impedance parameters. Presence or absence of gastro-esophageal reflux during barium esophagography does not correlate with incidence or extent of reflux observed during 24-h pH-impedance monitoring and is not of value for the diagnosis of GERD. © 2014 John Wiley & Sons Ltd.

A review of the health impacts of barium from natural and anthropogenic exposure.

PubMed

Kravchenko, Julia; Darrah, Thomas H; Miller, Richard K; Lyerly, H Kim; Vengosh, Avner

2014-08-01

There is an increasing public awareness of the relatively new and expanded industrial barium uses which are potential sources of human exposure (e.g., a shale gas development that causes an increased awareness of environmental exposures to barium). However, absorption of barium in exposed humans and a full spectrum of its health effects, especially among chronically exposed to moderate and low doses of barium populations, remain unclear. We suggest a systematic literature review (from 1875 to 2014) on environmental distribution of barium, its bioaccumulation, and potential and proven health impacts (in animal models and humans) to provide the information that can be used for optimization of future experimental and epidemiological studies and developing of mitigative and preventive strategies to minimize negative health effects in exposed populations. The potential health effects of barium exposure are largely based on animal studies, while epidemiological data for humans, specifically for chronic low-level exposures, are sparse. The reported health effects include cardiovascular and kidney diseases, metabolic, neurological, and mental disorders. Age, race, dietary patterns, behavioral risks (e.g., smoking), use of medications (those that interfere with absorbed barium in human organism), and specific physiological status (e.g., pregnancy) can modify barium effects on human health. Identifying, evaluating, and predicting the health effects of chronic low-level and moderate-level barium exposures in humans is challenging: Future research is needed to develop an understanding of barium bioaccumulation in order to mitigate its potential health impacts in various exposured populations. Further, while occupationally exposed at-risk populations exist, it is also important to identify potentially vulnerable subgroups among non-occupationally exposed populations (e.g., elderly, pregnant women, children) who are at higher risk of barium exposure from drinking water and food.

Analysis of a Superconductor: Development of a Practical Exam for the International Chemistry Olympiad

ERIC Educational Resources Information Center

Nick, Sabine; Nather, Christian

2007-01-01

In July 2004 the 36th International Chemistry Olympiad was held in Kiel, Germany. Competition for medals included 236 students from 61 countries, accompanied by about 150 teachers and other mentors. During this Olympiad the students performed qualitative and quantitative analyses of a superconductor, based on lanthanum barium cuprate. In the…

Tailored Barium Swallow Study

MedlinePlus

... sweetened and flavored. Special foods and containers, for example your child’s own cup, may be helpful in getting your child to drink in a more natural manner. What should you do after the test? Barium rarely causes any problems. It passes through ...

Upper gastrointestinal barium evaluation of duodenal pathology: A pictorial review

PubMed Central

Gupta, Pankaj; Debi, Uma; Sinha, Saroj Kant; Prasad, Kaushal Kishor

2014-01-01

Like other parts of the gastrointestinal tract (GIT), duodenum is subject to a variety of lesions both congenital and acquired. However, unlike other parts of the GIT viz. esophagus, rest of the small intestine and large intestine, barium evaluation of duodenal lesions is technically more challenging and hence not frequently reported. With significant advances in computed tomography technology, a thorough evaluation including intraluminal, mural and extramural is feasible in a single non-invasive examination. Notwithstanding, barium evaluation still remains the initial and sometimes the only imaging study in several parts of the world. Hence, a thorough acquaintance with the morphology of various duodenal lesions on upper gastrointestinal barium examination is essential in guiding further evaluation. We reviewed our experience with various common and uncommon barium findings in duodenal abnormalities. PMID:25170399

Single reconstructed Fermi surface pocket in an underdoped single-layer cuprate superconductor

DOE PAGES

Chan, Mun Keat; Harrison, Neil; Mcdonald, Ross David; ...

2016-07-22

The observation of a reconstructed Fermi surface via quantum oscillations in hole-doped cuprates opened a path towards identifying broken symmetry states in the pseudogap regime. However, such an identification has remained inconclusive due to the multi-frequency quantum oscillation spectra and complications accounting for bilayer effects in most studies. We overcome these impediments with high-resolution measurements on the structurally simpler cuprate HgBa2CuO4+δ (Hg1201), which features one CuO2 plane per primitive unit cell. We find only a single oscillatory component with no signatures of magnetic breakdown tunnelling to additional orbits. Therefore, the Fermi surface comprises a single quasi-two-dimensional pocket. Quantitative modelling ofmore » these results indicates that a biaxial charge density wave within each CuO2 plane is responsible for the reconstruction and rules out criss-crossed charge stripes between layers as a viable alternative in Hg1201. Lastly, we determine that the characteristic gap between reconstructed pockets is a significant fraction of the pseudogap energy« less

Quantum percolation in cuprate high-temperature superconductors

PubMed Central

Phillips, J. C.

2008-01-01

Although it is now generally acknowledged that electron–phonon interactions cause cuprate superconductivity with Tc values ≈100 K, the complexities of atomic arrangements in these marginally stable multilayer materials have frustrated both experimental analysis and theoretical modeling of the remarkably rich data obtained both by angle-resolved photoemission (ARPES) and high-resolution, large-area scanning tunneling microscopy (STM). Here, we analyze the theoretical background in terms of our original (1989) model of dopant-assisted quantum percolation (DAQP), as developed further in some two dozen articles, and apply these ideas to recent STM data. We conclude that despite all of the many difficulties, with improved data analysis it may yet be possible to identify quantum percolative paths. PMID:18626024

40 CFR 721.10011 - Barium calcium manganese strontium oxide.

Code of Federal Regulations, 2012 CFR

2012-07-01

... manganese strontium oxide (PMN P-00-1124; CAS No. 359427-90-0) is subject to reporting under this section... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Barium calcium manganese strontium... Specific Chemical Substances § 721.10011 Barium calcium manganese strontium oxide. (a) Chemical substance...

40 CFR 721.10011 - Barium calcium manganese strontium oxide.

Code of Federal Regulations, 2013 CFR

2013-07-01

... manganese strontium oxide (PMN P-00-1124; CAS No. 359427-90-0) is subject to reporting under this section... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Barium calcium manganese strontium... Specific Chemical Substances § 721.10011 Barium calcium manganese strontium oxide. (a) Chemical substance...

40 CFR 721.10011 - Barium calcium manganese strontium oxide.

Code of Federal Regulations, 2014 CFR

2014-07-01

... manganese strontium oxide (PMN P-00-1124; CAS No. 359427-90-0) is subject to reporting under this section... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Barium calcium manganese strontium... Specific Chemical Substances § 721.10011 Barium calcium manganese strontium oxide. (a) Chemical substance...

Sol-Gel Synthesis and Antioxidant Properties of Yttrium Oxide Nanocrystallites Incorporating P-123.

PubMed

Mellado-Vázquez, Rebeca; García-Hernández, Margarita; López-Marure, Arturo; López-Camacho, Perla Yolanda; de Jesús Morales-Ramírez, Ángel; Beltrán-Conde, Hiram Isaac

2014-09-19

Yttrium oxide (Y₂O₃) nanocrystallites were synthesized by mean of a sol-gel method using two different precursors. Raw materials used were yttrium nitrate and yttrium chloride, in methanol. In order to promote oxygen vacancies, P-123 poloxamer was incorporated. Synthesized systems were heat-treated at temperatures from 700 °C to 900 °C. Systems at 900 °C were prepared in the presence and absence of P-123 using different molar ratios (P-123:Y = 1:1 and 2:1). Fourier transform infrared spectroscopy (FTIR) results revealed a characteristic absorption band of Y-O vibrations typical of Y₂O₃ matrix. The structural phase was analyzed by X-ray diffraction (XRD), showing the characteristic cubic phase in all systems. The diffraction peak that presented the major intensity corresponded to the sample prepared from yttrium chloride incorporating P-123 in a molar ratio of P-123:Y = 2:1 at 900 °C. Crystallites sizes were determined by Scherrer equation as between 21 nm and 32 nm. Antioxidant properties were estimated by 2,2-diphenyl-1-picrylhydrazyl (DPPH•) assays; the results are discussed.

Topics in electronic structure and spectroscopy of cuprates

NASA Astrophysics Data System (ADS)

Lin, Hsin

I have applied first-principles calculations to investigate several interrelated problems concerned with the electronic structure and spectroscopy of cuprates. The specific topics addressed in this thesis are as follows. 1. By properly including doping effects beyond rigid band filling, a longstanding problem of the missing Bi-O pocket in the electronic structure of Bi2Sr2CaCu2O8 (Bi2212) is solved. The doping effect is explained in terms of Coulombic effect between layers and is a generic property of all cuprates. 2. A systematic study for Pb/O and rare-earth doping in Bi2212 is carried out to explain the experimental phase diagrams, and a possible new electron doped Bi2212 is predicted. 3. To investigate how the Mott insulators evolve into superconductors with the addition of holes, an analysis of angle-resolved photoemission (ARPES) data of La2-xSr xCuO4 is carried out over a wide doping range of x = 0.03 - 0.30. The spectrum displays the presence of the van Hove singularity (VHS) whose location in energy and three-dimensionality are in accord with the band theory predictions. A nascent metallic state is found in the lightly doped Mott insulator and develops spectral weight as doping increases. This metallic spectrum is 'universal' in the sense that its dispersion depends weakly on doping, in sharp contrast to the common expectation that dispersion is renormalized to zero at half-filling. This finding challenges existing theoretical scenarios for cuprates. 4. Self-consistent mean-field three- and four-band Hubbard models are used to study the Mott gap in electron-doped cuprates. The Hubbard terms are decomposed into a Mott-like term which describes the lifting of Cu bands due to energy cost U and a Slater-like term which describes an additional splitting of Cu bands due to antiferromagnetic (AFM) order. While no set of doping-independent parameters can explain the observed gaps for the entire doping range, the experimental results are consistent with a weakly

'Skidding' of the CRRES G-9 barium release

NASA Technical Reports Server (NTRS)

Huba, J. D.; Mitchell, H. G.; Fedder, J. A.; Bernhardt, P. A.

1992-01-01

A simulation study and experimental data of the CRRES G-9 ionospheric barium release are presented. The simulation study is based on a 2D electrostatic code that incorporates time-dependent coupling to the background plasma. It is shown that the densest portion of the barium ion cloud 'skids' about 15 km within the first three seconds following the release, consistent with the optical data analyses.

High pressure–low temperature phase diagram of barium: Simplicity versus complexity

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

Desgreniers, Serge; Tse, John S., E-mail: John.Tse@usask.ca; State Key Laboratory of Superhard Materials, Jilin University, 130012 Changchun

2015-11-30

Barium holds a distinctive position among all elements studied upon densification. Indeed, it was the first example shown to violate the long-standing notion that high compression of simple metals should preserve or yield close-packed structures. From modest pressure conditions at room temperature, barium transforms at higher pressures from its simple structures to the extraordinarily complex atomic arrangements of the incommensurate and self-hosting Ba-IV phases. By a detailed mapping of the pressure/temperature structures of barium, we demonstrate the existence of another crystalline arrangement of barium, Ba-VI, at low temperature and high pressure. The simple structure of Ba-VI is unlike that ofmore » complex Ba-IV, the phase encountered in a similar pressure range at room temperature. First-principles calculations predict Ba-VI to be stable at high pressure and superconductive. The results illustrate the complexity of the low temperature-high pressure phase diagram of barium and the significant effect of temperature on structural phase transformations.« less

Dynamics of correlation-frozen antinodal quasiparticles in superconducting cuprates

PubMed Central

Cilento, Federico; Manzoni, Giulia; Sterzi, Andrea; Peli, Simone; Ronchi, Andrea; Crepaldi, Alberto; Boschini, Fabio; Cacho, Cephise; Chapman, Richard; Springate, Emma; Eisaki, Hiroshi; Greven, Martin; Berciu, Mona; Kemper, Alexander F.; Damascelli, Andrea; Capone, Massimo; Giannetti, Claudio; Parmigiani, Fulvio

2018-01-01

Many puzzling properties of high–critical temperature (Tc) superconducting (HTSC) copper oxides have deep roots in the nature of the antinodal quasiparticles, the elementary excitations with wave vector parallel to the Cu–O bonds. These electronic states are most affected by the onset of antiferromagnetic correlations and charge instabilities, and they host the maximum of the anisotropic superconducting gap and pseudogap. We use time-resolved extreme-ultraviolet photoemission with proper photon energy (18 eV) and time resolution (50 fs) to disclose the ultrafast dynamics of the antinodal states in a prototypical HTSC cuprate. After photoinducing a nonthermal charge redistribution within the Cu and O orbitals, we reveal a dramatic momentum-space differentiation of the transient electron dynamics. Whereas the nodal quasiparticle distribution is heated up as in a conventional metal, new quasiparticle states transiently emerge at the antinodes, similarly to what is expected for a photoexcited Mott insulator, where the frozen charges can be released by an impulsive excitation. This transient antinodal metallicity is mapped into the dynamics of the O-2p bands, thus directly demonstrating the intertwining between the low- and high-energy scales that is typical of correlated materials. Our results suggest that the correlation-driven freezing of the electrons moving along the Cu–O bonds, analogous to the Mott localization mechanism, constitutes the starting point for any model of high-Tc superconductivity and other exotic phases of HTSC cuprates. PMID:29507885

Pseudogap temperature T* of cuprate superconductors from the Nernst effect

NASA Astrophysics Data System (ADS)

Cyr-Choinière, O.; Daou, R.; Laliberté, F.; Collignon, C.; Badoux, S.; LeBoeuf, D.; Chang, J.; Ramshaw, B. J.; Bonn, D. A.; Hardy, W. N.; Liang, R.; Yan, J.-Q.; Cheng, J.-G.; Zhou, J.-S.; Goodenough, J. B.; Pyon, S.; Takayama, T.; Takagi, H.; Doiron-Leyraud, N.; Taillefer, Louis

2018-02-01

We use the Nernst effect to delineate the boundary of the pseudogap phase in the temperature-doping phase diagram of hole-doped cuprate superconductors. New data for the Nernst coefficient ν (T ) of YBa2Cu3Oy (YBCO), La1.8 -xEu0.2SrxCuO4 (Eu-LSCO), and La1.6 -xNd0.4SrxCuO4 (Nd-LSCO) are presented and compared with previously published data on YBCO, Eu-LSCO, Nd-LSCO, and La2 -xSrxCuO4 (LSCO). The temperature Tν at which ν /T deviates from its high-temperature linear behavior is found to coincide with the temperature at which the resistivity ρ (T ) deviates from its linear-T dependence, which we take as the definition of the pseudogap temperature T★—in agreement with the temperature at which the antinodal spectral gap detected in angle-resolved photoemission spectroscopy (ARPES) opens. We track T★ as a function of doping and find that it decreases linearly vs p in all four materials, having the same value in the three LSCO-based cuprates, irrespective of their different crystal structures. At low p ,T★ is higher than the onset temperature of the various orders observed in underdoped cuprates, suggesting that these orders are secondary instabilities of the pseudogap phase. A linear extrapolation of T★(p ) to p =0 yields T★(p →0 ) ≃TN (0), the Néel temperature for the onset of antiferromagnetic order at p =0 , suggesting that there is a link between pseudogap and antiferromagnetism. With increasing p ,T★(p ) extrapolates linearly to zero at p ≃pc 2 , the critical doping below which superconductivity emerges at high doping, suggesting that the conditions which favor pseudogap formation also favor pairing. We also use the Nernst effect to investigate how far superconducting fluctuations extend above the critical temperature Tc, as a function of doping, and find that a narrow fluctuation regime tracks Tc, and not T★. This confirms that the pseudogap phase is not a form of precursor superconductivity, and fluctuations in the phase of the

Acceleration of barium ions near 8000 km above an aurora

NASA Technical Reports Server (NTRS)

Stenbaek-Nielsen, H. C.; Hallinan, T. J.; Wescott, E. M.; Foeppl, H.

1984-01-01

A barium shaped charge, named Limerick, was released from a rocket launched from Poker Flat Research Range, Alaska, on March 30, 1982, at 1033 UT. The release took place in a small auroral breakup. The jet of ionized barium reached an altitude of 8100 km 14.5 min after release, indicating that there were no parallel electric fields below this altitude. At 8100 km the jet appeared to stop. Analysis shows that the barium at this altitude was effectively removed from the tip. It is concluded that the barium was actually accelerated upward, resulting in a large decrease in the line-of-sight density and hence the optical intensity. The parallel electric potential in the acceleration region must have been greater than 1 kV over an altitude interval of less than 200 km. The acceleration region, although presumably auroral in origin, did not seem to be related to individual auroral structures, but appeared to be a large-scale horizontal structure. The perpendicular electric field below, as deduced from the drift of the barium, was temporally and spatially very uniform and showed no variation related to individual auroral structures passing through.

49 CFR 173.182 - Barium azide-50 percent or more water wet.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 2 2013-10-01 2013-10-01 false Barium azide-50 percent or more water wet. 173.182 Section 173.182 Transportation Other Regulations Relating to Transportation PIPELINE AND HAZARDOUS... Class 1 and Class 7 § 173.182 Barium azide—50 percent or more water wet. Barium azide—50 percent or more...

Indication of Confirmation of Transition and Formation Boundary from Ordered to Disordered Flux Vortex Chain State in High-Tc Superconductors Y1Ba2Cu3O7- δ and Bi2Sr2Ca2Cu3O10 and New Low-Field Data Delineating Magnetic Transition in Gd1Ba2(Fe0.02Cu0.98)3O7- δ

NASA Astrophysics Data System (ADS)

Vezzoli, G. Christopher; Chen, Michaeline F.; Burke, Terence; Rosen, Carol

1996-08-01

Data are presented herein that support a phase boundary or quasi-phase-boundary delineating in Y1Ba2Cu3O7-δ and in Bi2Sr2Ca2Cu3O10 ceramic materials a transition from a vortex solid lattice to a line-flux disordered state that has been referred to as representing flux lattice melting to a flux liquid, but herein is interpreted not in terms of a liquid but in the form of a less-mobile `polymer'-like or entangled chain species. These data are derived from electrical resistance (r) versus applied magnetic field (H) measurements at various isotherms (T) corresponding to the zero resistance state of yttrium--barium--cuprate, and the mixed state foot regime of bismuth--strontium--calcium--cuprate. We interpret significant slope changes in r versus B at constant T in these materials to be indicative of the H-T conditions for a second-order or weakly first-order phase transition delineating the disordering of a flux lattice vortex solid. We believe that this technique is in ways more direct and at least as accurate as the conventional mechanical oscillator and vibrating magnetometer method to study the flux state. Additional very-low-field studies in Gd1Ba2(Fe0.02Cu0.98)3O7-δ, from 1 to 1000 mT, yield indication for what appears to be a magnetic transition at ca. 77 K at 575 mT, and possibly a second transition at 912 mT (also at ca. 77 K). These data points correspond well with the extrapolated low-field experimental magnetic phase transition boundary curve described at higher field herein (and by others using the mechanical technique), and also correspond well to theoretically predicted work regarding transition involving the vortex state.

BARIUM REDUCTION OF INTUSSUSCEPTION IN INFANCY

PubMed Central

Denenholz, Edward J.; Feher, George. S.

1955-01-01

Barium enema reduction was used as the initial routine treatment in 29 infants with intussusception. In 22 of them the intussusception was reduced by this means. In three of eight patients operated upon the intussusception was found to be reduced. Four of the remaining five patients had clinical or x-ray evidence of complications before reduction by barium enema was attempted. Twenty-one of the patients, all of whom were observed in private practice, were treated without admission to the hospital. After reduction, these patients were observed closely by the clinician. None of these patients showed clinical or x-ray signs of complications before reduction. Certain clinical and roentgen criteria must be satisfied before it can be concluded that reduction by barium enema is complete. If there are clinical signs of complications with x-ray evidence of small bowel obstruction, only a very cautious attempt at hydrostatic reduction should be made. As the time factor is generally a reliable clinical guide to reducibility, the late cases should be viewed with greater caution. Long duration of symptoms, however, is not per se a contraindication to an attempt at hydrostatic reduction. PMID:13230908

Life Model of Hollow Cathodes Using a Barium Calcium Aluminate Impregnated Tungsten Emitter

NASA Technical Reports Server (NTRS)

Kovaleski, S. D.; Burke, Tom (Technical Monitor)

2001-01-01

Hollow cathodes with barium calcium aluminate impregnated tungsten emitters for thermionic emission are widely used in electric propulsion. These high current, low power cathodes are employed in ion thrusters, Hall thrusters, and on the International Space Station in plasma contactors. The requirements on hollow cathode life are growing more stringent with the increasing use of electric propulsion technology. The life limiting mechanism that determines the entitlement lifetime of a barium impregnated thermionic emission cathode is the evolution and transport of barium away from the emitter surface. A model is being developed to study the process of barium transport and loss from the emitter insert in hollow cathodes. The model accounts for the production of barium through analysis of the relevant impregnate chemistry. Transport of barium through the approximately static gas is also being treated. Finally, the effect of temperature gradients within the cathode are considered.

Endotrophic Calcium, Strontium, and Barium Spores of Bacillus megaterium and Bacillus cereus1

PubMed Central

Foerster, Harold F.; Foster, J. W.

1966-01-01

Foerster, Harold F. (The University of Texas, Austin), and J. W. Foster. Endotrophic calcium, strontium, and barium spores of Bacillus megaterium and Bacillus cereus. J. Bacteriol. 91:1333–1345. 1966.—Spores were produced by washed vegetative cells suspended in deionized water supplemented with CaCl2, SrCl2, or BaCl2. Normal, refractile spores were produced in each case; a portion of the barium spores lost refractility and darkened. Thin-section electron micrographs revealed no apparent anatomical differences among the three types of spores. Analyses revealed that the different spore types were enriched specifically in the metal to which they were exposed during sporogenesis. The calcium content of the strontium and the barium spores was very small. From binary equimolar mixtures of the metal salts, endotrophic spores accumulated both metals to nearly the same extent. Viability of the barium spores was considerably less than that of the other two types. Strontium and barium spores were heat-resistant; however, calcium was essential for maximal heat resistance. Significant differences existed in the rates of germination; calcium spores germinated fastest, strontium spores were slower, and barium spores were slowest. Calcium-barium and calcium-strontium spores germinated readily. Endotrophic calcium and strontium spores germinated without the prior heat activation essential for growth spores. Chemical germination of the different metal-type spores with n-dodecylamine took place at the same relative rates as physiological germination. Heat-induced release of dipicolinic acid occurred much faster with barium and strontium spores than with calcium spores. The washed “coat fraction” from disrupted spores contained little of the spore calcium but most of the spore barium. The metal in this fraction was released by dilute acid. The demineralized coats reabsorbed calcium and barium at neutral pH. Images PMID:4956334

Multi-layered proton-conducting electrolyte

DOEpatents

Lee, Tae H.; Dorris, Stephen E.; Balachandran, Uthamalingam

2017-06-27

The present invention provides a multilayer anode/electrolyte assembly comprising a porous anode substrate and a layered solid electrolyte in contact therewith. The layered solid electrolyte includes a first dense layer of yttrium-doped barium zirconate (BZY), optionally including another metal besides Y, Ba, and Zr (e.g., a lanthanide metal such as Pr) on one surface thereof, a second dense layer of yttrium-doped barium cerate (BCY), and an interfacial layer between and contacting the BZY and BCY layers. The interfacial layer comprises a solid solution of the BZY and BCY electrolytes. The porous anode substrate comprises at least one porous ceramic material that is stable to carbon dioxide and water (e.g., porous BZY), as well as an electrically conductive metal and/or metal oxide (e.g., Ni, NiO, and the like).

The Influence of Yttrium on High Temperature Oxidation of Valve Steels

NASA Astrophysics Data System (ADS)

Grzesik, Z.; Migdalska, M.; Mrowec, S.

2015-04-01

The influence of small amounts of yttrium, electrochemically deposited on the surface of four steels utilized in the production of valves in car engines, on the protective properties of the oxide scale and its adherence to the surface of the oxidized materials has been studied under isothermal and thermal cycle conditions. Oxidation measurements have been carried out at 1173 K. It has been found that yttrium addition improves considerably the scale adherence to the substrate surface, increasing thereby corrosion resistance of the studied materials.

Doping dependence of charge order in electron-doped cuprate superconductors

NASA Astrophysics Data System (ADS)

Mou, Yingping; Feng, Shiping

2017-12-01

In the recent studies of the unconventional physics in cuprate superconductors, one of the central issues is the interplay between charge order and superconductivity. Here the mechanism of the charge-order formation in the electron-doped cuprate superconductors is investigated based on the t-J model. The experimentally observed momentum dependence of the electron quasiparticle scattering rate is qualitatively reproduced, where the scattering rate is highly anisotropic in momentum space, and is intriguingly related to the charge-order gap. Although the scattering strength appears to be weakest at the hot spots, the scattering in the antinodal region is stronger than that in the nodal region, which leads to the original electron Fermi surface is broken up into the Fermi pockets and their coexistence with the Fermi arcs located around the nodal region. In particular, this electron Fermi surface instability drives the charge-order correlation, with the charge-order wave vector that matches well with the wave vector connecting the hot spots, as the charge-order correlation in the hole-doped counterparts. However, in a striking contrast to the hole-doped case, the charge-order wave vector in the electron-doped side increases in magnitude with the electron doping. The theory also shows the existence of a quantitative link between the single-electron fermiology and the collective response of the electron density.

Inverse correlation between quasiparticle mass and T c in a cuprate high-T c superconductor.

PubMed

Putzke, Carsten; Malone, Liam; Badoux, Sven; Vignolle, Baptiste; Vignolles, David; Tabis, Wojciech; Walmsley, Philip; Bird, Matthew; Hussey, Nigel E; Proust, Cyril; Carrington, Antony

2016-03-01

Close to a zero-temperature transition between ordered and disordered electronic phases, quantum fluctuations can lead to a strong enhancement of electron mass and to the emergence of competing phases such as superconductivity. A correlation between the existence of such a quantum phase transition and superconductivity is quite well established in some heavy fermion and iron-based superconductors, and there have been suggestions that high-temperature superconductivity in copper-oxide materials (cuprates) may also be driven by the same mechanism. Close to optimal doping, where the superconducting transition temperature T c is maximal in cuprates, two different phases are known to compete with superconductivity: a poorly understood pseudogap phase and a charge-ordered phase. Recent experiments have shown a strong increase in quasiparticle mass m* in the cuprate YBa2Cu3O7-δ as optimal doping is approached, suggesting that quantum fluctuations of the charge-ordered phase may be responsible for the high-T c superconductivity. We have tested the robustness of this correlation between m* and T c by performing quantum oscillation studies on the stoichiometric compound YBa2Cu4O8 under hydrostatic pressure. In contrast to the results for YBa2Cu3O7-δ, we find that in YBa2Cu4O8, the mass decreases as T c increases under pressure. This inverse correlation between m* and T c suggests that quantum fluctuations of the charge order enhance m* but do not enhance T c.

Theory of asymmetric tunneling in the cuprate superconductors

NASA Astrophysics Data System (ADS)

Anderson, P. W.; Ong, N. P.

2006-01-01

We explain quantitatively, within the Gutzwiller-Resonating Valence Bond theory, the puzzling observation of tunneling conductivity between a metallic point and a cuprate high-Tc superconductor which is markedly asymmetric between positive and negative voltage biases. The asymmetric part does not have a ‘coherence peak’ but does show structure due to the gap. The fit to data is satisfactory within the over-simplifications of the theory; in particular, it explains the marked ‘peak-dip-hump’ structure observed on the hole side and a number of other qualitative observations. This asymmetry is strong evidence for the projective nature of the ground state and hence for ‘t-J’ physics.

Status of barium studies in the present era of oncology: Are they a history?

PubMed Central

Mahajan, Abhishek; Desai, Subash; Sable, Nilesh Pandurang; Thakur, Meenakshi Haresh

2016-01-01

With the advent of the modern imaging technologies, the present era of oncology is seeing steady decline in requests for barium studies due to the many reasons. It is prudent to mention here, that, barium examinations cannot be made obsolete! Our aim to preserve the age old technique of barium studies not only to keep it going on but also for the betterment and appropriate management of the patient. Our goal is not to “save” barium studies simply to keep this technology alive, per se, but rather to preserve barium radiology for the quality in patient care. PMID:28144086

Status of barium studies in the present era of oncology: Are they a history?

PubMed

Mahajan, Abhishek; Desai, Subash; Sable, Nilesh Pandurang; Thakur, Meenakshi Haresh

2016-01-01

With the advent of the modern imaging technologies, the present era of oncology is seeing steady decline in requests for barium studies due to the many reasons. It is prudent to mention here, that, barium examinations cannot be made obsolete! Our aim to preserve the age old technique of barium studies not only to keep it going on but also for the betterment and appropriate management of the patient. Our goal is not to "save" barium studies simply to keep this technology alive, per se, but rather to preserve barium radiology for the quality in patient care.

Lower GI Series (Barium Enema)

MedlinePlus

... You may be asked to change position several times to evenly coat the large intestine with the barium. If you are having a double-contrast lower GI series, the radiologist will inject air through the tube ...

Yttrium recovery from primary and secondary sources: A review of main hydrometallurgical processes

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

Innocenzi, Valentina, E-mail: valentina.innocenzi1@univaq.it; De Michelis, Ida; Kopacek, Bernd

2014-07-15

Highlights: • Review of the main hydrometallurgical processes to recover yttrium. • Recovery of yttrium from primary sources. • Recovery of yttrium from e-waste and other types of waste. - Abstract: Yttrium is important rare earths (REs) used in numerous fields, mainly in the phosphor powders for low-energy lighting. The uses of these elements, especially for high-tech products are increased in recent years and combined with the scarcity of the resources and the environmental impact of the technologies to extract them from ores make the recycling waste, that contain Y and other RE, a priority. The present review summarized themore » main hydrometallurgical technologies to extract Y from ores, contaminated solutions, WEEE and generic wastes. Before to discuss the works about the treatment of wastes, the processes to retrieval Y from ores are discussed, since the processes are similar and derived from those already developed for the extraction from primary sources. Particular attention was given to the recovery of Y from WEEE because the recycle of them is important not only for economical point of view, considering its value, but also for environmental impact that this could be generated if not properly disposal.« less

Sol-Gel Synthesis and Antioxidant Properties of Yttrium Oxide Nanocrystallites Incorporating P-123

PubMed Central

Mellado-Vázquez, Rebeca; García-Hernández, Margarita; López-Marure, Arturo; López-Camacho, Perla Yolanda; Morales-Ramírez, Ángel de Jesús; Beltrán-Conde, Hiram Isaac

2014-01-01

Yttrium oxide (Y2O3) nanocrystallites were synthesized by mean of a sol-gel method using two different precursors. Raw materials used were yttrium nitrate and yttrium chloride, in methanol. In order to promote oxygen vacancies, P-123 poloxamer was incorporated. Synthesized systems were heat-treated at temperatures from 700 °C to 900 °C. Systems at 900 °C were prepared in the presence and absence of P-123 using different molar ratios (P-123:Y = 1:1 and 2:1). Fourier transform infrared spectroscopy (FTIR) results revealed a characteristic absorption band of Y–O vibrations typical of Y2O3 matrix. The structural phase was analyzed by X-ray diffraction (XRD), showing the characteristic cubic phase in all systems. The diffraction peak that presented the major intensity corresponded to the sample prepared from yttrium chloride incorporating P-123 in a molar ratio of P-123:Y = 2:1 at 900 °C. Crystallites sizes were determined by Scherrer equation as between 21 nm and 32 nm. Antioxidant properties were estimated by 2,2-diphenyl-1-picrylhydrazyl (DPPH•) assays; the results are discussed. PMID:28788211

Cuprate High Temperature Superconductors and the Vision for Room Temperature Superconductivity

NASA Astrophysics Data System (ADS)

Newns, Dennis M.; Martyna, Glenn J.; Tsuei, Chang C.

Superconducting transition temperatures of 164 K in cuprate high temperature superconductors (HTS) and recently 200 K in H3S under high pressure encourage us to believe that room temperature superconductivity (RTS) might be possible. In considering paths to RTS, we contrast conventional (BCS) SC, such as probably manifested by H3S, with the unconventional superconductivity (SC) in the cuprate HTS family. Turning to SC models, we show that in the presence of one or more van Hove singularities (vHs) near the Fermi level, SC mediated by classical phonons (kBTc>ℏ×phonon frequency) can occur. The phonon frequency in the standard Tc formula is replaced by an electronic cutoff, enabling a much higher Tc independent of phonon frequency. The resulting Tc and isotope shift plot versus doping strongly resembles that seen experimentally in HTS. A more detailed theory of HTS, which involves mediation by classical phonons, satisfactorily reproduces the chief anomalous features characteristic of these materials. We propose that, while a path to RTS through an H3S-like scenario via strongly-coupled ultra-high frequency phonons is attractive, features perhaps unavailable at ordinary pressures, a route involving SC mediated by classical phonons which can be low frequency may be found.

Raman and fluorescence characteristics of resonant inelastic X-ray scattering from doped superconducting cuprates

DOE PAGES

Huang, H. Y.; Jia, C. J.; Chen, Z. Y.; ...

2016-01-22

Measurements of spin excitations are essential for an understanding of spin-mediated pairing for superconductivity; and resonant inelastic X-ray scattering (RIXS) provides a considerable opportunity to probe high-energy spin excitations. However, whether RIXS correctly measures the collective spin excitations of doped superconducting cuprates remains under debate. Here we demonstrate distinct Raman- and fluorescence-like RIXS excitations of Bi1.5Pb0.6Sr1.54CaCu2O8+δ. Combining photon-energy and momentum dependent RIXS measurements with theoretical calculations using exact diagonalization provides conclusive evidence that the Raman-like RIXS excitations correspond to collective spin excitations, which are magnons in the undoped Mott insulators and evolve into paramagnons in doped superconducting compounds. In contrast,more » the fluorescence-like shifts are due primarily to the continuum of particle-hole excitations in the charge channel. Our results show that under the proper experimental conditions RIXS indeed can be used to probe paramagnons in doped high-Tc cuprate superconductors.« less

OXIDATION-RESISTANT COATING ON ARTICLES OF YTTRIUM METAL

DOEpatents

Wilder, D.R.; Wirkus, C.D.

1963-11-01

A process for protecting yttrium metal from oxidation by applying thereto and firing thereon a liquid suspension of a fritted ground silicate or phosphate glass plus from 5 to 35% by weight of CeO/sub 2/ is presented. (AEC)

Synthesis of nanocomposites comprising iron and barium hexaferrites

NASA Astrophysics Data System (ADS)

Pal, M.; Bid, S.; Pradhan, S. K.; Nath, B. K.; Das, D.; Chakravorty, D.

2004-02-01

Composites of nanometre-sized α-iron and barium hexaferrite phases, respectively, have been synthesized by the ceramic processing route. Pure barium hexaferrite (BaO·6Fe 2O 3) was first of all prepared by calcinations of the precursor oxides at a maximum temperature of 1200°C for 4 h. By subjecting the resulting powder having particle size of the order of 1 μm to a reduction treatment in the temperature range 500-650°C for a period varying from 10 to 15 min it was possible to obtain a composite consisting of nanosized barium hexaferrite and α-Fe. At reduction temperature of 650°C for a period greater than 15 min all the ferrite phase was converted to α-Fe and Ba—the particle sizes being 59.4 and 43.6 nm, respectively. These conclusions are based on X-ray diffraction and Mossbauer studies of different samples. During reduction H + ions are introduced into the hexaferrite crystallite. It is believed that due to a tensile stress the crystals are broken up into smaller dimensions and the reduction brings about the growth of nanosized α-Fe and barium, respectively, around the hexaferrite particles. Magnetic measurements show coercivity values for the reduced samples in the range 120-440 Oe and saturation magnetization varying from 158 to 53.7 emu/g. These values have been ascribed to the formation and growth of α-Fe particles as the reduction treatment is increased. By heating the nanocomposites at a temperature of 1000°C for 1 h in ordinary atmosphere it was found that they were reconverted to the barium hexaferrite phase with a particle size ˜182.3 nm. The reaction described in this study is thus reversible.

Preliminary study of the CRRES magnetospheric barium releases

NASA Technical Reports Server (NTRS)

Huba, J. D.; Bernhardt, P. A.; Lyon, J. G.

1992-01-01

Preliminary theoretical and computational analyses of the Combined Release and Radiation Effects Satellite (CRRES) magnetospheric barium releases are presented. The focus of the studies is on the evolution of the diamagnetic cavity which is formed by the barium ions as they expand outward, and on the structuring of the density and magnetic field during the expansion phase of the releases. Two sets of simulation studies are discussed. The first set is based upon a 2D ideal MHD code and provides estimates of the time and length scales associated with the formation and collapse of the diamagnetic cavity. The second set uses a nonideal MHD code; specifically, the Hall term is included. This additional term is critical to the dynamics of sub-Alfvenic plasma expansions, such as the CRRES barium releases, because it leads to instability of the expanding plasma. Detailed simulations of the G4 and G10 releases were performed. In both cases the expanding plasma rapidly structured: the G4 release structured at time t less than about 3 s and developed scale sizes of about 1-2 km, while the G10 release structured at time t less than about 22 s and developed scale sizes of about 10-15 km. It is also found that the diamagnetic cavity size is reduced from those obtained from the ideal MHD results because of the structure. On the other hand, the structuring allows the formation of plasma blobs which appear to free stream across the magnetic field; thus, the barium plasma can propagate to larger distances traverse to the magnetic field than the case where no structuring occurs. Finally, a new normal mode of the system was discovered which may be excited at the leading edge of the expanding barium plasma.

Biochemical investigation of yttrium(III) complex containing 1,10-phenanthroline: DNA binding and antibacterial activity.

PubMed

Khorasani-Motlagh, Mozhgan; Noroozifar, Meissam; Moodi, Asieh; Niroomand, Sona

2013-03-05

Characterization of the interaction between yttrium(III) complex containing 1,10-phenanthroline as ligand, [Y(phen)2Cl(OH2)3]Cl2⋅H2O, and DNA has been carried out by UV absorption, fluorescence spectra and viscosity measurements in order to investigate binding mode. The experimental results indicate that the yttrium(III) complex binds to DNA and absorption is decreasing in charge transfer band with the increase in amount of DNA. The binding constant (Kb) at different temperatures as well as thermodynamic parameters, enthalpy change (ΔH°) and entropy change (ΔS°), were calculated according to relevant fluorescent data and Vant' Hoff equation. The results of interaction mechanism studies, suggested that groove binding plays a major role in the binding of the complex and DNA. The activity of yttrium(III) complex against some bacteria was tested and antimicrobial screening tests shown growth inhibitory activity in the presence of yttrium(III) complex. Copyright © 2013 Elsevier B.V. All rights reserved.

49 CFR 173.182 - Barium azide-50 percent or more water wet.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 2 2011-10-01 2011-10-01 false Barium azide-50 percent or more water wet. 173.182... Class 1 and Class 7 § 173.182 Barium azide—50 percent or more water wet. Barium azide—50 percent or more water wet, must be packed in wooden boxes (4C1, 4C2, 4D, or 4F) or fiber drums (1G) with inner glass...

49 CFR 173.182 - Barium azide-50 percent or more water wet.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 2 2010-10-01 2010-10-01 false Barium azide-50 percent or more water wet. 173.182... Class 1 and Class 7 § 173.182 Barium azide—50 percent or more water wet. Barium azide—50 percent or more water wet, must be packed in wooden boxes (4C1, 4C2, 4D, or 4F) or fiber drums (1G) with inner glass...

Synthesis and surface properties of submicron barium sulfate particles

NASA Astrophysics Data System (ADS)

Zhang, Ming; Zhang, Bao; Li, Xinhai; Yin, Zhoulan; Guo, Xueyi

2011-10-01

Barium sulfate particles were synthesized in the presence of EDTA at room temperature. X-ray diffractometry (XRD), Fourier transform infrared resonance (FTIR) and scanning electron microscopy (SEM) were used to characterize the structure and morphology of BaSO 4 particles. The effect of the preparation parameters on the particle size distribution and morphology was investigated. The conditional formation constants of Ba-EDTA at different pH values were calculated. The results show that the size and morphology of BaSO 4 particles can be effectively controlled by adding EDTA in the precipitation process. Among all the operation conditions, the pH value has significant effect on the particle size. The obtained barium sulfate particles are spherical and well dispersed at pH = 9-10. Zeta potentials of BaSO 4 were measured at different pH. The isoelectric point (IEP) of barium sulfate colloid appears at pH 6.92. The model of the solid-solution interface at a particle of BaSO 4 was presented. The FTIR result indicates that the surface of the prepared BaSO 4 absorbs the functional groups of EDTA, which lower the IEP of the barium sulfate particles.

Probing optically silent superfluid stripes in cuprates

NASA Astrophysics Data System (ADS)

Rajasekaran, S.; Okamoto, J.; Mathey, L.; Fechner, M.; Thampy, V.; Gu, G. D.; Cavalleri, A.

2018-02-01

Unconventional superconductivity in the cuprates coexists with other types of electronic order. However, some of these orders are invisible to most experimental probes because of their symmetry. For example, the possible existence of superfluid stripes is not easily validated with linear optics, because the stripe alignment causes interlayer superconducting tunneling to vanish on average. Here we show that this frustration is removed in the nonlinear optical response. A giant terahertz third harmonic, characteristic of nonlinear Josephson tunneling, is observed in La1.885Ba0.115CuO4 above the transition temperature Tc = 13 kelvin and up to the charge-ordering temperature Tco = 55 kelvin. We model these results by hypothesizing the presence of a pair density wave condensate, in which nonlinear mixing of optically silent tunneling modes drives large dipole-carrying supercurrents.

Mechanisms for Superconductivity in Cuprates compared with results from the Generalized MacMillan-Rowell Analysis of High Resolution Laser- ARPES

NASA Astrophysics Data System (ADS)

Varma, Chandra; Choi, Han-Yong; Zhang, Wentao; Zhou, Xingjiang

2012-02-01

The spectra of fluctuations and their coupling to fermions has been deduced from extensive high resolution laser ARPES in several BISCCO samples and quantitatively analyzed. We ask the question whether some of the theories for superconductivity in Cuprates are consistent or inconsistent with the frequency and the momentum dependence of the deductions. We find that any fluctuation spectra, for example that of Antiferromagnetic Fluctuations, whose frequency dependence depends significantly on momentum dependence are excluded. We consider the quantum-critical spectra of the loop-current order observed in under-doped cuprates and its coupling to fermions and find it consistent with the data.

Characteristics of the Mott transition and electronic states of high-temperature cuprate superconductors from the perspective of the Hubbard model

NASA Astrophysics Data System (ADS)

Kohno, Masanori

2018-04-01

A fundamental issue of the Mott transition is how electrons behaving as single particles carrying spin and charge in a metal change into those exhibiting separated spin and charge excitations (low-energy spin excitation and high-energy charge excitation) in a Mott insulator. This issue has attracted considerable attention particularly in relation to high-temperature cuprate superconductors, which exhibit electronic states near the Mott transition that are difficult to explain in conventional pictures. Here, from a new viewpoint of the Mott transition based on analyses of the Hubbard model, we review anomalous features observed in high-temperature cuprate superconductors near the Mott transition.

Sorption of strontium-90 from fresh waters during sulfate modification of barium manganite

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

Ryzhen`kov, A.P.; Egorov, Yu.V.

1995-11-01

Recovery of strontium-90 with barium manganite from fresh waters (natural fresh waters of open basins) can be increased by adding agents that contain sulfate ions and thus modify the sorbent and chemically bind the sorbate. The treatment results in a heterogeneous anion-exchange transformation of barium manganite into barium sulfate-manganese dioxide and in simultaneous absorptive coprecipitation of strontium sulfate (microcomponent).

Self-optimized superconductivity attainable by interlayer phase separation at cuprate interfaces.

PubMed

Misawa, Takahiro; Nomura, Yusuke; Biermann, Silke; Imada, Masatoshi

2016-07-01

Stabilizing superconductivity at high temperatures and elucidating its mechanism have long been major challenges of materials research in condensed matter physics. Meanwhile, recent progress in nanostructuring offers unprecedented possibilities for designing novel functionalities. Above all, thin films of cuprate and iron-based high-temperature superconductors exhibit remarkably better superconducting characteristics (for example, higher critical temperatures) than in the bulk, but the underlying mechanism is still not understood. Solving microscopic models suitable for cuprates, we demonstrate that, at an interface between a Mott insulator and an overdoped nonsuperconducting metal, the superconducting amplitude is always pinned at the optimum achieved in the bulk, independently of the carrier concentration in the metal. This is in contrast to the dome-like dependence in bulk superconductors but consistent with the astonishing independence of the critical temperature from the carrier density x observed at the interfaces of La2CuO4 and La2-x Sr x CuO4. Furthermore, we identify a self-organization mechanism as responsible for the pinning at the optimum amplitude: An emergent electronic structure induced by interlayer phase separation eludes bulk phase separation and inhomogeneities that would kill superconductivity in the bulk. Thus, interfaces provide an ideal tool to enhance and stabilize superconductivity. This interfacial example opens up further ways of shaping superconductivity by suppressing competing instabilities, with direct perspectives for designing devices.

Self-optimized superconductivity attainable by interlayer phase separation at cuprate interfaces

PubMed Central

Misawa, Takahiro; Nomura, Yusuke; Biermann, Silke; Imada, Masatoshi

2016-01-01

Stabilizing superconductivity at high temperatures and elucidating its mechanism have long been major challenges of materials research in condensed matter physics. Meanwhile, recent progress in nanostructuring offers unprecedented possibilities for designing novel functionalities. Above all, thin films of cuprate and iron-based high-temperature superconductors exhibit remarkably better superconducting characteristics (for example, higher critical temperatures) than in the bulk, but the underlying mechanism is still not understood. Solving microscopic models suitable for cuprates, we demonstrate that, at an interface between a Mott insulator and an overdoped nonsuperconducting metal, the superconducting amplitude is always pinned at the optimum achieved in the bulk, independently of the carrier concentration in the metal. This is in contrast to the dome-like dependence in bulk superconductors but consistent with the astonishing independence of the critical temperature from the carrier density x observed at the interfaces of La2CuO4 and La2−xSrxCuO4. Furthermore, we identify a self-organization mechanism as responsible for the pinning at the optimum amplitude: An emergent electronic structure induced by interlayer phase separation eludes bulk phase separation and inhomogeneities that would kill superconductivity in the bulk. Thus, interfaces provide an ideal tool to enhance and stabilize superconductivity. This interfacial example opens up further ways of shaping superconductivity by suppressing competing instabilities, with direct perspectives for designing devices. PMID:27482542

The effect of yttrium and thorium on the oxidation behavior of Ni-Cr-Al alloys

NASA Technical Reports Server (NTRS)

Kumar, A.; Nasrallah, M.; Douglass, D. L.

1974-01-01

The effect of quaternary additions of 0.5% Y, 0.5 and 1.0% Th to a base alloy of Ni-10CR-5Al on the oxidation behavior and mechanism was studied during oxidation in air over the range of 1000 to 1200 C. The presence of yttrium decreased the oxidation kinetics slightly, whereas, the addition of thorium caused a slight increase. Oxide scale adherence was markedly improved by the addition of the quaternary elements. Although a number of oxides formed on yttrium containing alloys, quantitative X-ray diffraction clearly showed that the rate-controlling step was the diffusion of aluminum through short circuit paths in a thin layer of alumina that formed parabolically with time. Although the scale adherence of the yttrium containing alloy was considerably better than the base alloys, spalling did occur that was attributed to the formation of the voluminous YAG particles which grew in a mushroom-like manner, lifting the protective scale off the subrate locally. The YAG particles formed primarily at grain boundaries in the substrate in which the yttrium originally existed as YNi9.

The reactive element effect of yttrium and yttrium silicon on high temperature oxidation of NiCrAl coating

NASA Astrophysics Data System (ADS)

Ramandhany, S.; Sugiarti, E.; Desiati, R. D.; Martides, E.; Junianto, E.; Prawara, B.; Sukarto, A.; Tjahjono, A.

2018-03-01

The microstructure formed on the bond coat affects the oxidation resistance, particularly the formation of a protective oxide layer. The adhesion of bond coat and TGO increased significantly by addition of reactive element. In the present work, the effect of yttrium and yttrium silicon as reactive element (RE) on NiCrAl coating was investigated. The NiCrAl (without RE) and NiCrAlX (X:Y or YSi) bond coating were deposited on Hastelloy C-276 substrate by High Velocity Oxygen Fuel (HVOF) method. Isothermal oxidation was carried out at 1000 °C for 100 hours. The results showed that the addition of RE could prevent the breakaway oxidation. Therefore, the coating with reactive element were more protective against high temperature oxidation. Furthermore, the oxidation rate of NiCrAlY coating was lower than NiCrAlYSi coating with the total mass change was ±2.394 mg/cm2 after 100 hours of oxidation. The thickness of oxide scale was approximately 1.18 μm consisting of duplex oxide scale of spinel NiCr2O4 in outer scale and protective α-Al2O3 in inner scale.

A Study on Factors Affecting the Degradation of Magnesium and a Magnesium-Yttrium Alloy for Biomedical Applications

PubMed Central

Johnson, Ian; Liu, Huinan

2013-01-01

Controlling degradation of magnesium or its alloys in physiological saline solutions is essential for their potential applications in clinically viable implants. Rapid degradation of magnesium-based materials reduces the mechanical properties of implants prematurely and severely increases alkalinity of the local environment. Therefore, the objective of this study is to investigate the effects of three interactive factors on magnesium degradation, specifically, the addition of yttrium to form a magnesium-yttrium alloy versus pure magnesium, the metallic versus oxide surfaces, and the presence versus absence of physiological salt ions in the immersion solution. In the immersion solution of phosphate buffered saline (PBS), the magnesium-yttrium alloy with metallic surface degraded the slowest, followed by pure magnesium with metallic or oxide surfaces, and the magnesium-yttrium alloy with oxide surface degraded the fastest. However, in deionized (DI) water, the degradation rate showed a different trend. Specifically, pure magnesium with metallic or oxide surfaces degraded the slowest, followed by the magnesium-yttrium alloy with oxide surface, and the magnesium-yttrium alloy with metallic surface degraded the fastest. Interestingly, only magnesium-yttrium alloy with metallic surface degraded slower in PBS than in DI water, while all the other samples degraded faster in PBS than in DI water. Clearly, the results showed that the alloy composition, presence or absence of surface oxide layer, and presence or absence of physiological salt ions in the immersion solution all influenced the degradation rate and mode. Moreover, these three factors showed statistically significant interactions. This study revealed the complex interrelationships among these factors and their respective contributions to degradation for the first time. The results of this study not only improved our understanding of magnesium degradation in physiological environment, but also presented the key

Alteration of the fast excitatory postsynaptic current by barium in voltage-clamped amphibian sympathetic ganglion cells.

PubMed Central

Connor, E. A.; Parsons, R. L.

1984-01-01

Barium-induced alterations in fast excitatory postsynaptic currents (e.p.s.cs) have been studied in voltage-clamped bullfrog sympathetic ganglion B cells. In the presence of 2-8 mM barium, e.p.s.c. decay was prolonged and in many cells the e.p.s.c. decay phase deviated from a single exponential function. The decay phase in these cases was more accurately described as the sum of two exponential functions. The frequency of occurrence of a complex decay increased both with increasing barium concentration and with hyperpolarization. Miniature e.p.s.c. decay also was prolonged in barium-treated cells. E.p.s.c. amplitude was not markedly affected by barium (2-8 mM) in cells voltage-clamped to -50 mV whereas at -90 mV there was a progressive increase in peak size with increasing barium concentration. In control cells the e.p.s.c.-voltage relationship was linear between -20 and -100 mV; however, this relationship became progressively non-linear with membrane hyperpolarization in barium-treated cells. The e.p.s.c. reversal potential was shifted to a more negative value in the presence of barium. There was a voltage-dependent increase in charge movement during the e.p.s.c. in barium-treated cells which was not present in control cells. We conclude that the voltage-dependent alteration in e.p.s.c. decay time course, peak amplitude and charge movement in barium-treated cells is due to a direct postsynaptic action of barium on the kinetics of receptor-channel gating in postganglionic sympathetic neurones. PMID:6333261

Yttrium-90 microspheres for the treatment of hepatocellular carcinoma: A review

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

Salem, Riad; Hunter, Russell D.

2006-10-01

To present a critical review of yttrium-90 (TheraSphere) for the treatment of hepatocellular carcinoma (HCC). Medical literature databases (Medline, Cochrane Library, and CANCERLIT) were searched for available literature concerning the treatment of HCC with TheraSphere. These publications were reviewed for scientific and clinical validity. Studies pertaining to the use of yttrium-90 for HCC date back to the 1960s. The results from the early animal safety studies established a radiation exposure range of 50-100 Gy to be used in human studies. Phase I dose escalation studies followed, which were instrumental in delineating radiation dosimetry and safety parameters in humans. These earlymore » studies emphasized the importance of differential arteriolar density between hypervascular HCC and surrounding liver parenchyma. Current trends in research have focused on advancing techniques to safely implement this technology as an alternative to traditional methods of treating unresectable HCC, such as external beam radiotherapy, conformal beam radiotherapy, ethanol ablation, trans-arterial chemoembolization, and radiofrequency ablation. Yttrium-90 (TheraSphere) is an outpatient treatment option for HCC. Current and future research should focus on implementing multicenter phase II and III trials comparing TheraSphere with other therapies for HCC.« less

Change of carrier density at the pseudogap critical point of a cuprate superconductor.

PubMed

Badoux, S; Tabis, W; Laliberté, F; Grissonnanche, G; Vignolle, B; Vignolles, D; Béard, J; Bonn, D A; Hardy, W N; Liang, R; Doiron-Leyraud, N; Taillefer, Louis; Proust, Cyril

2016-03-10

The pseudogap is a partial gap in the electronic density of states that opens in the normal (non-superconducting) state of cuprate superconductors and whose origin is a long-standing puzzle. Its connection to the Mott insulator phase at low doping (hole concentration, p) remains ambiguous and its relation to the charge order that reconstructs the Fermi surface at intermediate doping is still unclear. Here we use measurements of the Hall coefficient in magnetic fields up to 88 tesla to show that Fermi-surface reconstruction by charge order in the cuprate YBa2Cu3Oy ends sharply at a critical doping p = 0.16 that is distinctly lower than the pseudogap critical point p* = 0.19 (ref. 11). This shows that the pseudogap and charge order are separate phenomena. We find that the change in carrier density n from n = 1 + p in the conventional metal at high doping (ref. 12) to n = p at low doping (ref. 13) starts at the pseudogap critical point. This shows that the pseudogap and the antiferromagnetic Mott insulator are linked.

Treatment of unresectable intrahepatic cholangiocarcinoma with yttrium-90 radioembolization: a systematic review and pooled analysis.

PubMed

Al-Adra, D P; Gill, R S; Axford, S J; Shi, X; Kneteman, N; Liau, S-S

2015-01-01

Radioembolization with yttrium-90 microspheres offers an alternative treatment option for patients with unresectable intrahepatic cholangiocarcinoma (ICC). However, the rarity and heterogeneity of ICC makes it difficult to draw firm conclusions about treatment efficacy. Therefore, the goal of the current study is to systematically review the existing literature surrounding treatment of unresectable ICCs with yttrium-90 microspheres and provide a comprehensive review of the current experience and clinical outcome of this treatment modality. We performed a comprehensive search of electronic databases for ICC treatment and identified 12 studies with relevant data regarding radioembolization therapy with yttrium-90 microspheres. Based on pooled analysis, the overall weighted median survival was 15.5 months. Tumour response based on radiological studies demonstrated a partial response in 28% and stable disease in 54% of patients at three months. Seven patients were able to be downstaged to surgical resection. The complication profile of radioembolization is similar to that of other intra-arterial treatment modalities. Overall survival of patients with ICC after treatment with yttrium-90 microspheres is higher than historical survival rates and shows similar survival to those patients treated with systemic chemotherapy and/or trans-arterial chemoembolization therapy. Therefore, the use of yttrium-90 microspheres should be considered in the list of available treatment options for ICC. However, future randomized trials comparing systemic chemotherapy, TACE and local radiation will be required to identify the optimal treatment modality for unresectable ICC. Crown Copyright © 2014. Published by Elsevier Ltd. All rights reserved.

Probing optically silent superfluid stripes in cuprates

DOE PAGES

Rajasekaran, S.; Okamoto, J.; Mathey, L.; ...

2018-02-02

Unconventional superconductivity in the cuprates coexists with other types of electronic order. However, some of these orders are invisible to most experimental probes because of their symmetry. For example, the possible existence of superfluid stripes is not easily validated with linear optics, because the stripe alignment causes interlayer superconducting tunneling to vanish on average. In this paper, we show that this frustration is removed in the nonlinear optical response. A giant terahertz third harmonic, characteristic of nonlinear Josephson tunneling, is observed in La 1.885Ba 0.115CuO 4 above the transition temperature T c = 13 kelvin and up to the charge-orderingmore » temperature T co = 55 kelvin. We model these results by hypothesizing the presence of a pair density wave condensate, in which nonlinear mixing of optically silent tunneling modes drives large dipole-carrying supercurrents.« less

Probing optically silent superfluid stripes in cuprates

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

Rajasekaran, S.; Okamoto, J.; Mathey, L.

Unconventional superconductivity in the cuprates coexists with other types of electronic order. However, some of these orders are invisible to most experimental probes because of their symmetry. For example, the possible existence of superfluid stripes is not easily validated with linear optics, because the stripe alignment causes interlayer superconducting tunneling to vanish on average. In this paper, we show that this frustration is removed in the nonlinear optical response. A giant terahertz third harmonic, characteristic of nonlinear Josephson tunneling, is observed in La 1.885Ba 0.115CuO 4 above the transition temperature T c = 13 kelvin and up to the charge-orderingmore » temperature T co = 55 kelvin. We model these results by hypothesizing the presence of a pair density wave condensate, in which nonlinear mixing of optically silent tunneling modes drives large dipole-carrying supercurrents.« less

How does esophagus look on barium esophagram in pediatric eosinophilic esophagitis?

PubMed

Al-Hussaini, Abdulrahman; AboZeid, Amany; Hai, Abdul

2016-08-01

The clinical, endoscopic, and histologic findings of eosinophilic esophagitis (EoE) are well characterized; however, there have been very limited data regarding the radiologic findings of pediatric EoE. We report on the radiologic findings of pediatric EoE observed on barium esophagram and correlate them with the endoscopic findings. We identified children diagnosed with EoE in our center from 2004 to 2015. Two pediatric radiologists met after their independent evaluations of each fluoroscopic study to reach a consensus on each case. Clinical and endoscopic data were collected by retrospective chart review. Twenty-six pediatric EoE cases (age range 2-13 years; median 7.5 years) had barium esophagram done as part of the diagnostic approach for dysphagia. Thirteen children had abnormal radiologic findings of esophagus (50%): rings formation (n = 4), diffuse irregularity of mucosa (n = 8), fixed stricture formation (n = 3), and narrow-caliber esophagus (n = 10). Barium esophagram failed to show one of 10 cases of narrow-caliber esophagus and 10 of 14 cases of rings formation visualized endoscopically. The mean duration of symptoms prior to diagnosis of EoE was longer (3.7 vs. 1.7 year; p value 0.019), and the presentation with intermittent food impaction was commoner in the group with abnormal barium esophagram as compared to the group with normal barium esophagram (69% vs. 8%; p value 0.04). Barium swallow study is frequently normal in pediatric EoE. With the exception of narrow-caliber esophagus, our data show poor correlation between radiologic and endoscopic findings.

Tunable ferromagnetic resonance in La-Co substituted barium hexaferrites at millimeter wave frequencies

NASA Astrophysics Data System (ADS)

Korolev, Konstantin A.; Wu, Chuanjian; Yu, Zhong; Sun, Ke; Afsar, Mohammed N.; Harris, Vincent G.

2018-05-01

Transmittance measurements have been performed on La-Co substituted barium hexaferrites in millimeter waves. Broadband millimeter-wave measurements have been carried out using the free space quasi-optical spectrometer, equipped with a set of high power backward wave oscillators covering the frequency range of 30 - 120 GHz. Strong absorption zones have been observed in the millimeter-wave transmittance spectra of all La-Co substituted barium hexaferrites due to the ferromagnetic resonance. Linear shift of ferromagnetic resonance frequency as functions of La-Co substitutions have been found. Real and imaginary parts of dielectric permittivity of La-Co substituted barium hexaferrites have been calculated using the analysis of recorded high precision transmittance spectra. Frequency dependences of magnetic permeability of La-Co substituted barium hexaferrites, as well as saturation magnetization and anisotropy field have been determined based on Schlömann's theory for partially magnetized ferrites. La-Co substituted barium hexaferrites have been further investigated by DC magnetization to assess magnetic behavior and compare with millimeter wave data. Consistency of saturation magnetization determined independently by both millimeter wave absorption and DC magnetization have been found for all La-Co substituted barium hexaferrites. These materials seem to be quite promising as tunable millimeter wave absorbers, filters, circulators, based on the adjusting of their substitution parameters.

Toward (-)-Enterocin: An Improved Cuprate Barbier Protocol To Overcome Strain and Sterical Hindrance.

PubMed

Rizzo, Antonio; Trauner, Dirk

2018-04-06

An approach toward (-)-enterocin, an antibiotic isolated from Streptomyces hygroscopicus, is described. Its compact, heavily oxidized protoadamantane core represents a daunting challenge for an efficient synthesis. Convergent assembly of its 2-oxabicyclo[3.3.1]nonane core with a cuprate-mediated Barbier reaction is disclosed. Its functionalization to a suitable substrate for a biomimetic aldol to close the final ring of the natural product is evaluated.

A search for technetium (Tc II) in barium stars

NASA Technical Reports Server (NTRS)

Little-Marenin, Irene R.; Little, Stephen J.

1987-01-01

The authors searched without success for the lines of Tc II at 2647.02, 2610.00 and 2543.24 A in IUE spectra of the barium stars HR 5058, Omicron Vir, and Zeta Cap. The lack of Tc II implies that the observed s-process enhancements were produced more than half a million years ago and supports the suggestion that the spectral peculiarities of barium stars are probably related to the binary nature of the stars.

Intensity-Dependence Absorption and Photorefractive Effects in Barium Titanate

DTIC Science & Technology

1988-09-01

S) barium titanate (U) George A. Brost , Ra and A. Motes, James R. Rotge’ 13& TYPE OF REPORT 13b. TIME COVERED 14. DATE OF REPORT (Yr.. Mo.. Day) 15...the copyright owner. Inthnsity-dependent absorption and photorefractive effects in barium titanate0 ELECTE 0 G. A. Brost , R. A. Motes, and 1. R. Rotge...Opt. Soc. Am. B/Vol. 5, No. 9/September 1988 Brost et al. CONDUCTION BAND the relative contributions of photoconductivities and dark conductivities

Lanthanide doped strontium-barium cesium halide scintillators

DOEpatents

Bizarri, Gregory; Bourret-Courchesne, Edith; Derenzo, Stephen E.; Borade, Ramesh B.; Gundiah, Gautam; Yan, Zewu; Hanrahan, Stephen M.; Chaudhry, Anurag; Canning, Andrew

2015-06-09

The present invention provides for a composition comprising an inorganic scintillator comprising an optionally lanthanide-doped strontium-barium, optionally cesium, halide, useful for detecting nuclear material.

Fabrication and characterization of cerium-doped barium titanate inverse opal by sol-gel method

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

Jin Yi; Zhu Yihua; Yang Xiaoling

Cerium-doped barium titanate inverted opal was synthesized from barium acetate contained cerous acetate and tetrabutyl titanate in the interstitial spaces of a polystyrene (PS) opal. This procedure involves infiltration of precursors into the interstices of the PS opal template followed by hydrolytic polycondensation of the precursors to amorphous barium titanate and removal of the PS opal by calcination. The morphologies of opal and inverse opal were characterized by scanning electron microscope (SEM). The pores were characterized by mercury intrusion porosimetry (MIP). X-ray photoelectron spectroscopy (XPS) investigation showed the doping structure of cerium, barium and titanium. And powder X-ray diffraction allowsmore » one to observe the influence of doping degree on the grain size. The lattice parameters, crystal size and lattice strain were calculated by the Rietveld refinement method. The synthesis of cerium-doped barium titanate inverted opals provides an opportunity to electrically and optically engineer the photonic band structure and the possibility of developing tunable three-dimensional photonic crystal devices. - Graphical abstract: Cerium-doped barium titanate inverted opal was synthesized from barium acetate acid contained cerous acetate and tetrabutyl titanate in the interstitial spaces of a PS opal, which involves infiltration of precursors into the interstices of the PS opal template and removal of the PS opal by calcination.« less

Barium Isotopes in Single Presolar Grains

NASA Technical Reports Server (NTRS)

Pellin, M. J.; Davis, A. M.; Savina, M. R.; Kashiv, Y.; Clayton, R. N.; Lewis, R. S.; Amari, S.

2001-01-01

Barium isotopic compositions of single presolar grains were measured by laser ablation laser resonant ionization mass spectrometry and the implications of the data for stellar processes are discussed. Additional information is contained in the original extended abstract.

Photonuclear production of yttrium-88 - A high energy gamma emitter for hydrocarbon extraction applications.

PubMed

Dale, Daniel S; Starovoitova, Valeriia N; Forest, Tony A; Oliphant, Emily

2018-05-05

The use of fracing has risen over the past decade and revolutionized energy production in the US. However, there is still an impetus for further optimization of the extraction of oil and natural gas from vast shale reservoirs. In this work, we discuss photonuclear production of yttrium-88 as a promising radiotracer for fracing operations. Single neutron knock-out from natural monoisotopic yttrium-89 is an inexpensive process resulting in high activity of 88 Y with minimal impurities. MCNPX simulations were performed to estimate the 88 Y yield. Irradiations of natural yttrium using a 32 MeV electron linac equipped with a tungsten bremsstrahlung converter were done to benchmark the simulations. Activities of 88 Y, 87g Y, and 87m Y were measured and found to be in good agreement with the predictions. Copyright © 2018 Elsevier Ltd. All rights reserved.

Quantitative description of yttrium aluminate ceramic composition by means of Er+3 microluminescence spectrum

NASA Astrophysics Data System (ADS)

Videla, F. A.; Tejerina, M. R.; Moreira-Osorio, L.; Conconi, M. S.; Orzi, D. J. O.; Flores, T.; Ponce, L. V.; Bilmes, G. M.; Torchia, G. A.

2018-05-01

The composition of erbium-doped yttrium aluminate ceramics was analyzed by means of confocal luminescence spectroscopy, EDX, and X-ray diffraction. A well-defined linear correlation was found between a proposed estimator computed from the luminescence spectrum and the proportion of ceramic phases coexisting in different samples. This result shows the feasibility of using erbium luminescence spectroscopy to perform a quantitative determination of different phases of yttrium aluminates within a micrometric region in nanograined ceramics.

Superconducting composite with multilayer patterns and multiple buffer layers

DOEpatents

Wu, X.D.; Muenchausen, R.E.

1993-10-12

An article of manufacture is described including a substrate, a patterned interlayer of a material selected from the group consisting of magnesium oxide, barium-titanium oxide or barium-zirconium oxide, the patterned interlayer material overcoated with a secondary interlayer material of yttria-stabilized zirconia or magnesium-aluminum oxide, upon the surface of the substrate whereby an intermediate article with an exposed surface of both the overcoated patterned interlayer and the substrate is formed, a coating of a buffer layer selected from the group consisting of cerium oxide, yttrium oxide, curium oxide, dysprosium oxide, erbium oxide, europium oxide, iron oxide, gadolinium oxide, holmium oxide, indium oxide, lanthanum oxide, manganese oxide, lutetium oxide, neodymium oxide, praseodymium oxide, plutonium oxide, samarium oxide, terbium oxide, thallium oxide, thulium oxide, yttrium oxide and ytterbium oxide over the entire exposed surface of the intermediate article, and, a ceramic superconductor. 5 figures.

Development of biomonitoring equivalents for barium in urine and plasma for interpreting human biomonitoring data.

PubMed

Poddalgoda, Devika; Macey, Kristin; Assad, Henry; Krishnan, Kannan

2017-06-01

The objectives of the present work were: (1) to assemble population-level biomonitoring data to identify the concentrations of urinary and plasma barium across the general population; and (2) to derive biomonitoring equivalents (BEs) for barium in urine and plasma in order to facilitate the interpretation of barium concentrations in the biological matrices. In population level biomonitoring studies, barium has been measured in urine in the U.S. (NHANES study), but no such data on plasma barium levels were identified. The BE values for plasma and urine were derived from U.S. EPA's reference dose (RfD) of 0.2 mg/kg bw/d, based on a lower confidence limit on the benchmark dose (BMDL 05 ) of 63 mg/kg bw/d. The plasma BE (9 μg Ba/L) was derived by regression analysis of the near-steady-state plasma concentrations associated with the administered doses in animals exposed to barium chloride dihydrate in drinking water for 2-years in a NTP study. Using a human urinary excretion fraction of 0.023, a BE for urinary barium (0.19 mg/L or 0.25 mg/g creatinine) was derived for US EPA's RfD. The median and the 95 th percentile barium urine concentrations of the general population in U.S. are below the BE determined in this study, indicating that the population exposure to inorganic barium is expected to be below the exposure guidance value of 0.2 mg/kg bw/d. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

Severe acute cholangitis after endoscopic sphincterotomy induced by barium examination: A case report

PubMed Central

Zhang, Zhen-Hai; Wu, Ya-Guang; Qin, Cheng-Kun; Su, Zhong-Xue; Xu, Jian; Xian, Guo-Zhe; Wu, Shuo-Dong

2012-01-01

Endoscopic sphincterotomy (EST) is considered as a possible etiological factor for severe cholangitis. We herein report a case of severe cholangitis after endoscopic sphincterotomy induced by barium examination. An adult male patient presented with epigastric pain was diagnosed as having choledocholithiasis by ultrasonography. EST was performed and the stone was completely cleaned. Barium examination was done 3 d after EST and severe cholangitis appeared 4 h later. The patient was recovered after treated with tienam for 4 d. Barium examination may induce severe cholangitis in patients after EST, although rare, barium examination should be chosen cautiously. Cautions should be also used when EST is performed in patients younger than 50 years to avoid the damage to the sphincter of Oddi. PMID:23112564

Severe acute cholangitis after endoscopic sphincterotomy induced by barium examination: A case report.

PubMed

Zhang, Zhen-Hai; Wu, Ya-Guang; Qin, Cheng-Kun; Su, Zhong-Xue; Xu, Jian; Xian, Guo-Zhe; Wu, Shuo-Dong

2012-10-21

Endoscopic sphincterotomy (EST) is considered as a possible etiological factor for severe cholangitis. We herein report a case of severe cholangitis after endoscopic sphincterotomy induced by barium examination. An adult male patient presented with epigastric pain was diagnosed as having choledocholithiasis by ultrasonography. EST was performed and the stone was completely cleaned. Barium examination was done 3 d after EST and severe cholangitis appeared 4 h later. The patient was recovered after treated with tienam for 4 d. Barium examination may induce severe cholangitis in patients after EST, although rare, barium examination should be chosen cautiously. Cautions should be also used when EST is performed in patients younger than 50 years to avoid the damage to the sphincter of Oddi.

Ong construction for the reconstructed Fermi surface of underdoped cuprates

NASA Astrophysics Data System (ADS)

Robinson, P.; Hussey, N. E.

2015-12-01

Using the Ong construction for a two-dimensional metal, we show that the sign change in the Hall coefficient RH of underdoped hole-doped cuprates at low temperature is consistent with the emergence of biaxial charge order recently proposed to explain the observation of low-frequency quantum oscillations. The sharp evolution of RH with temperature, however, can only be reconciled by incorporating a highly anisotropic quasiparticle scattering rate. The magnitude and form of the scattering rate extracted from the fitting imply that those quasiparticles at the vertices of the reconstructed pocket(s) approach the boundary of incoherence at the onset of charge order.

Regeneration of barium carbonate from barium sulphide in a pilot-scale bubbling column reactor and utilization for acid mine drainage.

PubMed

Mulopo, J; Zvimba, J N; Swanepoel, H; Bologo, L T; Maree, J

2012-01-01

Batch regeneration of barium carbonate (BaCO(3)) from barium sulphide (BaS) slurries by passing CO(2) gas into a pilot-scale bubbling column reactor under ambient conditions was used to assess the technical feasibility of BaCO(3) recovery in the Alkali Barium Calcium (ABC) desalination process and its use for sulphate removal from high sulphate Acid Mine Drainage (AMD). The effect of key process parameters, such as BaS slurry concentration and CO(2) flow rate on the carbonation, as well as the extent of sulphate removal from AMD using the recovered BaCO(3) were investigated. It was observed that the carbonation reaction rate for BaCO(3) regeneration in a bubbling column reactor significantly increased with increase in carbon dioxide (CO(2)) flow rate whereas the BaS slurry content within the range 5-10% slurry content did not significantly affect the carbonation rate. The CO(2) flow rate also had an impact on the BaCO(3) morphology. The BaCO(3) recovered from the pilot-scale bubbling column reactor demonstrated effective sulphate removal ability during AMD treatment compared with commercial BaCO(3).

Phonon anharmonicity of monoclinic zirconia and yttrium-stabilized zirconia

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

Li, Chen W.; Smith, Hillary L.; Lan, Tian

2015-04-13

Inelastic neutron scattering measurements on monoclinic zirconia (ZrO 2) and 8 mol% yttrium-stabilized zirconia were performed at temperatures from 300 to 1373 ωK. We reported temperature-dependent phonon densities of states (DOS) and Raman spectra obtained at elevated temperatures. First-principles lattice dynamics calculations with density functional theory gave total and partial phonon DOS curves and mode Grüneisen parameters. These mode Grüneisen parameters were used to predict the experimental temperature dependence of the phonon DOS with partial success. However, substantial anharmonicity was found at elevated temperatures, especially for phonon modes dominated by the motions of oxygen atoms. Yttrium-stabilized zirconia (YSZ) was somewhatmore » more anharmonic and had a broader phonon spectrum at low temperatures, owing in part to defects in its structure. YSZ also has a larger vibrational entropy than monoclinic zirconia.« less

Barium versus nonbarium stimuli: differences in taste intensity, chemesthesis, and swallowing behavior in healthy adult women.

PubMed

Nagy, Ahmed; Steele, Catriona M; Pelletier, Cathy A

2014-06-01

The authors examined the impact of barium on the perceived taste intensity of 7 different liquid tastant stimuli and the modulatory effect that these differences in perceived taste intensity have on swallowing behaviors. Participants were 80 healthy women, stratified by age group (<40; >60) and genetic taste status (supertasters; nontasters). Perceived taste intensity and chemesthetic properties (fizziness; burning-stinging) were rated for 7 tastant solutions (each prepared with and without barium) using the general Labeled Magnitude Scale. Tongue-palate pressures and submental surface electromyography (sEMG) were simultaneously measured during swallowing of these same randomized liquids. Path analysis differentiated the effects of stimulus, genetic taste status, age, barium condition, taste intensity, and an effortful saliva swallow strength covariate on swallowing. Barium stimuli were rated as having reduced taste intensity compared with nonbarium stimuli. Barium also dampened fizziness but did not influence burning-stinging sensation. The amplitudes of tongue-palate pressure or submental sEMG did not differ when swallowing barium versus nonbarium stimuli. Despite impacting taste intensity, the addition of barium to liquid stimuli does not appear to alter behavioral parameters of swallowing. Barium solutions can be considered to elicit behaviors that are similar to those used with nonbarium liquids outside the assessment situation.

Determination of barium in natural waters by ICP-OES technique. Part II: Assessment of human exposure to barium in bottled mineral and spring waters produced in Poland.

PubMed

Garboś, Sławomir; Swiecicka, Dorota

2013-01-01

A method of the classification of natural mineral and spring waters and maximum admissible concentration (MAC) levels of metals present in such types of waters are regulated by Commission Directive 2003/40/EC, Directive 2009/54/EC of the European Parliament and of the Council and Ordinance of Minister of Health of 30 March 2011 on the natural mineral waters, spring waters and potable waters. MAC of barium in natural mineral and spring waters was set at 1.0 mg/l, while World Health Organization determined the Ba guideline value in water intended for human consumption at the level of 0.7 mg/l. The aims of the study were: the determination of barium in natural mineral and spring waters (carbonated, non-carbonated and medium-carbonated waters) produced and bottled on the area of Poland, and assessment of human exposure to this metal presents in the above-mentioned types of waters. The study concerning barium determinations in 23 types of bottled natural mineral waters and 15 types of bottled spring waters (bought in Polish retail outlets) was conducted in 2010. The analyses were performed by validated method of determination of barium in water based on inductively coupled plasma optical emission spectrometry, using modern internal quality control scheme. Concentrations of barium determined in natural mineral and spring waters were in the ranges from 0.0136 mg/l to 1.12 mg/l and from 0.0044 mg/l to 0.43 mg/l, respectively. Only in the single case of natural mineral water the concentration of barium (1.12 mg/l), exceeded above-mentioned MAC for this metal, which is obligatory in Poland and the European Union - 1.0 mg/l. The long-term monitoring of barium concentration in another natural mineral water (2006 - 2010), in which incidental exceeding MAC was observed in 2006, was conducted. All measured barium concentrations in this water were lower than 1.0 mg/l and therefore, it is possible to state that the proper method of mixing waters taken from six independent

Heat capacity of rare-earth cuprates, orthovanadates, and aluminum garnets, gallium garnets, and iron garnets

NASA Astrophysics Data System (ADS)

Denisova, L. T.; Kargin, Yu. F.; Denisov, V. M.

2015-08-01

The correlation between the heat capacities of rare-earth cuprates, orthovanadates, and garnets with ionic radius R 3+ has been analyzed. It has been shown that the values of C {/p 0} change consistently depending on the radius R 3+ within the corresponding tetrads (La-Nd, Pm-Gd, Gd-Ho, Eu-Lu).

Method of forming a relatively stable slip of silicon metal particles and yttrium containing particles

DOEpatents

Dickie, Ray A.; Mangels, John A.

1984-01-01

The method concerns forming a relatively stable slip of silicon metal particles and yttrium containing particles. In one embodiment, a casting slip of silicon metal particles is formed in water. Particles of a yttrium containing sintering aid are added to the casting slip. The yttrium containing sintering aid is a compound which has at least some solubility in water to form Y.sup.+3 ions which have a high potential for totally flocculating the silicon metal particles into a semiporous solid. A small amount of a fluoride salt is added to the casting slip which contains the yttrium containing sintering aid. The fluoride salt is one which will produce fluoride anions when dissolved in water. The small amount of the fluoride anions produced are effective to suppress the flocculation of the silicon metal particles by the Y.sup.+3 ions so that all particles remain in suspension in the casting slip and the casting slip has both an increased shelf life and can be used to cast articles having a relatively thick cross-section. The pH of the casting slip is maintained in a range from 7.5 to 9. Preferably, the fluoride salt used is one which is based on a monovalent cation such as sodium or ammonia. The steps of adding the yttrium containing sintering aid and the fluoride salt may be interchanged if desired, and the salt may be added to a solution containing the sintering aid prior to addition of the silicon metal particles.

Characterization of yttrium-rich precipitates in a titanium alloy weld

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

Kolli, R. Prakash, E-mail: pkolli@umd.edu

The yttrium-rich (Y-rich) precipitates that form in the fusion zone (FZ) of a Ti–5Al–1Sn–1Zr–1V–0.8Mo (wt.%) alloy, or Ti-5111, gas-tungsten arc welds (GTAW) were characterized. The filler metal was modified by a small concentration of Y in order to refine the microstructure and thus improve the FZ ductility. A high number density of nanoscale Y-rich precipitates were characterized in the weld FZ by atom probe tomography (APT) and scanning transmission electron microscopy (STEM). - Highlights: •A high number density of nanoscale precipitates were observed in the FZ matrix. •The nanoscale precipitates are enriched in yttrium. •Oxygen and sulfur are also presentmore » in the Y-rich precipitates and their interfaces.« less

Multiphoton laser ionization for energy conversion in barium vapor

NASA Astrophysics Data System (ADS)

Makdisi, Y.; Kokaj, J.; Afrousheh, K.; Mathew, J.; Nair, R.; Pichler, G.

2013-03-01

We have studied the ion detection of barium atoms in special heated ovens with a tungsten rod in the middle of the stainless steel tube. The tungsten rod was heated indirectly by the oven body heaters. A bias voltage between the cell body and the tungsten rod of 9 V was used to collect electrons, after the barium ions had been created. However, we could collect the electrons even without the bias voltage, although with ten times less efficiency. We studied the conditions for the successful bias-less thermionic signal detection using excimer/dye laser two-photon excitation of Rydberg states below and above the first ionization limit (two-photon wavelength at 475.79 nm). We employed a hot-pipe oven and heat-pipe oven (with inserted mesh) in order to generate different barium vapor distributions inside the oven. The thermionic signal increased by a factor of two under heat-pipe oven conditions.

Effects of yttrium, aluminum, and chromium concentrations in bond coatings on the performance of zirconia-yttria thermal barriers

NASA Technical Reports Server (NTRS)

Stecura, S.

1979-01-01

A cyclic furnace study was conducted between 990 - 280 C and 1095 - 280 C to evaluate the effects of yttrium, chromium, and aluminum concentrations in nickel base alloy bond coatings and also the effect of the bond coating thickness on the performance of yttria-stabilized zirconia thermal barrier coatings. The presence and the concentration of yttrium is very critical. Without yttrium, rapid oxidation of Ni-Al, Ni-Cr, and Ni-Cr-Al bond coatings causes zirconia thermal barrier coatings to fail very rapidly. Concentrations of chrominum and aluminum in Ni-Cr-Al-Y bond coating have a very significant effect on the thermal barrier coating life. This effect, however, is not as great as that due to yttrium. Furthermore, the thickness and the thickness uniformity also have a very significant effect on the life of the thermal barrier system.

Barium inhibits arsenic-mediated apoptotic cell death in human squamous cell carcinoma cells.

PubMed

Yajima, Ichiro; Uemura, Noriyuki; Nizam, Saika; Khalequzzaman, Md; Thang, Nguyen D; Kumasaka, Mayuko Y; Akhand, Anwarul A; Shekhar, Hossain U; Nakajima, Tamie; Kato, Masashi

2012-06-01

Our fieldwork showed more than 1 μM (145.1 μg/L) barium in about 3 μM (210.7 μg/L) arsenic-polluted drinking well water (n = 72) in cancer-prone areas in Bangladesh, while the mean concentrations of nine other elements in the water were less than 3 μg/L. The types of cancer include squamous cell carcinomas (SCC). We hypothesized that barium modulates arsenic-mediated biological effects, and we examined the effect of barium (1 μM) on arsenic (3 μM)-mediated apoptotic cell death of human HSC-5 and A431 SCC cells in vitro. Arsenic promoted SCC apoptosis with increased reactive oxygen species (ROS) production and JNK1/2 and caspase-3 activation (apoptotic pathway). In contrast, arsenic also inhibited SCC apoptosis with increased NF-κB activity and X-linked inhibitor of apoptosis protein (XIAP) expression level and decreased JNK activity (antiapoptotic pathway). These results suggest that arsenic bidirectionally promotes apoptotic and antiapoptotic pathways in SCC cells. Interestingly, barium in the presence of arsenic increased NF-κB activity and XIAP expression and decreased JNK activity without affecting ROS production, resulting in the inhibition of the arsenic-mediated apoptotic pathway. Since the anticancer effect of arsenic is mainly dependent on cancer apoptosis, barium-mediated inhibition of arsenic-induced apoptosis may promote progression of SCC in patients in Bangladesh who keep drinking barium and arsenic-polluted water after the development of cancer. Thus, we newly showed that barium in the presence of arsenic might inhibit arsenic-mediated cancer apoptosis with the modulation of the balance between arsenic-mediated promotive and suppressive apoptotic pathways.

Umklapp scattering as the origin of T -linear resistivity in the normal state of high- T c cuprate superconductors

DOE PAGES

Rice, T. Maurice; Robinson, Neil J.; Tsvelik, Alexei M.

2017-12-11

Here, the high-temperature normal state of the unconventional cuprate superconductors has resistivity linear in temperature T, which persists to values well beyond the Mott-Ioffe-Regel upper bound. At low temperatures, within the pseudogap phase, the resistivity is instead quadratic in T, as would be expected from Fermi liquid theory. Developing an understanding of these normal phases of the cuprates is crucial to explain the unconventional superconductivity. We present a simple explanation for this behavior, in terms of the umklapp scattering of electrons. This fits within the general picture emerging from functional renormalization group calculations that spurred the Yang-Rice-Zhang ansatz: Umklapp scatteringmore » is at the heart of the behavior in the normal phase.« less

Synthesis and characterization of barium hexaferrite with manganese (Mn) doping material as anti-radar

NASA Astrophysics Data System (ADS)

Susilawati, Doyan, Aris; Khalilurrahman

2017-01-01

Have been successfully synthesized barium powder doping Manganese hexaferrite with the expected potential as anti-radar material. Synthesis was done by using the co-precipitation method, the variation of the variable x concentrations used were 0; 0.2; 0.4; and 0.6 and calcined at temperatures of 400, 600 and 800°C. Characterization powders of hexaferrite have used XRD (X-Ray Diffraction), SEM (Scanning Electron Microscopy), TEM (Transmission Electron Microscopy), LCR (inductance, capacitance, and resistance) meter, and VSM (Vibrating Sample Magnetometer). The higher the concentration and temperature of calcinations given affect the color of the powder. The test results using XRD indicates that it has formed barium hexaferrite phase with a hexagonal crystal structure. Tests using SEM showed that all the constituent elements barium powder hexaferrite by doping Manganese powders have been spread evenly. XRD test results were confirmed by a test using a TEM showing the crystal structure and the powder was sized nano particles. The results from the LCR meter showed that the barium powder hexaferrite by doping Manganese that has been synthesized classified in semiconductor materials. The result from VSM showed that the value of coercivity magnetic powder doped barium hexaferrite Manganese is smaller when compared with barium hexaferrite without doping and belong to the soft magnetic. Based on the results of the synthesis and characterization, we can conclude that the barium powder heksaferrite by doping Manganese potential as a material anti-radar.

North Pacific barium isotope distributions illustrate importance of ocean mixing in controlling barium distributions despite weak regional circulation

NASA Astrophysics Data System (ADS)

Geyman, B.; Auro, M. E. E.; LaVigne, M.; Ptacek, J. L.; Horner, T. J.

2016-12-01

The dissolved behavior of barium in the ocean exhibits a `refractory' nutrient-type profile similar to that of silicon, which has led to the use of Ba as a proxy for paleo-productivity and carbon cycling. Marine barium cycling appears to be controlled by the precipitation of micron-scale barite crystals in the mesopelagic and their subsequent dissolution throughout the water column, which has been shown to impart an isotopic signature that may itself harbor information about ocean circulation and export production. However, the utility of Ba-based proxies in chemical and paleoceanography relies on a sound understanding of the processes governing marine barium distributions, which remain unresolved. Here, we report the first full oceanographic depth profile of barium isotopes from the North Pacific Ocean (30 N, 140 W), which offers the ability to resolve biogeochemical cycling from mixing processes in a given water mass. Our data confirm findings from other oceanographic regions showing a close coupling between increasing [Ba] and decreasing Ba-isotope compositions with depth. Unlike other profiles however, this coupling is restricted to the upper 1,000 m of the North Pacific water column, with samples from between 1,000 m and 4,500 m showing a roughly 60 % increase in [Ba] but essentially no changes in their Ba-isotope compositions (within measurement uncertainty of 15 ppm/AMU). As with Atlantic data, samples spanning the entire profile define a linear trend (R2 > 0.9) when plotted as Ba-isotope compositions against 1/[Ba], indicating that conservative mixing can account for much of the Ba-isotope variation in the North Pacific water column. Overall, these findings highlight the utility of stable isotope measurements to illuminate the processes governing nutrient cycling, and support the critical role of large-scale ocean circulation in setting `refractory' nutrient distributions. These results have particular relevance to regions with relatively weak overturning

Ionization and expansion of barium clouds in the ionosphere

NASA Technical Reports Server (NTRS)

Ma, T.-Z.; Schunk, R. W.

1993-01-01

A recently envelope 3D model is used here to study the motion of the barium clouds released in the ionosphere, including the ionization stage. The ionization and the expansion of the barium clouds and the interaction between the clouds and the background ions are investigated using three simulations: a cloud without a directional velocity, a cloud with an initial velocity of 5 km/s across the B field, and a cloud with initial velocity components of 2 km/s both along and across the B field.

REVIEW ARTICLE: Unconventional isotope effects in the high-temperature cuprate superconductors

NASA Astrophysics Data System (ADS)

Zhao, Guo-meng; Keller, H.; Conder, K.

2001-07-01

We review various isotope effects in the high-Tc cuprate superconductors to assess the role of the electron-phonon interaction in the basic physics of these materials. Of particular interest are the unconventional isotope effects on the supercarrier mass, on the charge-stripe formation temperature, on the pseudogap formation temperature, on the electron paramagnetic resonance (EPR) linewidth, on the spin-glass freezing temperature and on the antiferromagnetic ordering temperature. The observed unconventional isotope effects strongly suggest that lattice vibrations play an important role in the microscopic pairing mechanism of high-temperature superconductivity.

Fluctuation-exchange study of antiferromagnetism in disordered electron-doped cuprate superconductors.

PubMed

Yan, Xin-Zhong; Ting, C S

2006-08-11

On the basis of the Hubbard model, we extend the fluctuation-exchange (FLEX) approach to investigating the properties of the antiferromagnetic (AF) phase in electron-doped cuprate superconductors. Furthermore, by incorporating the effect of scatterings due to the disordered dopant atoms into the FLEX formalism, our numerical results show that the antiferromagnetic transition temperature, the onset temperature of pseudogap due to spin fluctuations, the spectral density of the single particle near the Fermi surface, and the staggered magnetization in the AF phase as a function of electron doping can consistently account for the experimental measurements.

Numberical simulation of the effects of radially injected barium plasma in the ionosphere

NASA Technical Reports Server (NTRS)

Swift, D. W.

1985-01-01

The morphology of the ion cloud in the radial shaped charge barium injection was studied. The shape of the ion cloud that remains after the explosive products and neutral barium clears away was examined. The ion cloud which has the configuration of a rimless wagon wheel is shown. The major features are the 2.5 km radius black hole in the center of the cloud, the surrounding ring of barium ion and the spokes of barium ionization radiating away from the center. The cloud shows no evolution after it emerges from the neutral debris and it is concluded that it is formed within 5 seconds of the event. A numerical model is used to calculate the motion of ions and electrons subject to the electrostatic and lorenz forces.

Intraprocedural yttrium-90 positron emission tomography/CT for treatment optimization of yttrium-90 radioembolization.

PubMed

Bourgeois, Austin C; Chang, Ted T; Bradley, Yong C; Acuff, Shelley N; Pasciak, Alexander S

2014-02-01

Radioembolization with yttrium-90 ((90)Y) microspheres relies on delivery of appropriate treatment activity to ensure patient safety and optimize treatment efficacy. We report a case in which (90)Y positron emission tomography (PET)/computed tomography (CT) was performed to optimize treatment planning during a same-day, three-part treatment session. This treatment consisted of (i) an initial (90)Y infusion with a dosage determined using an empiric treatment planning model, (ii) quantitative (90)Y PET/CT imaging, and (iii) a secondary infusion with treatment planning based on quantitative imaging data with the goal of delivering a specific total tumor absorbed dose. © 2014 SIR Published by SIR All rights reserved.

Comparison of two barium suspensions for dedicated small-bowel series.

PubMed

Davidson, J C; Einstein, D M; Herts, B R; Balfe, D M; Koehler, R E; Morgan, D E; Lieber, M; Baker, M E

1999-02-01

The in vivo radiographic features of two commercially available formulations of barium used as contrast media in dedicated small-bowel series were compared. Fifty-six consecutive outpatients referred for a dedicated small-bowel series were randomly administered either E-Z-Paque or Entrobar. Representative survey radiographs from each examination were randomized and reviewed by six gastrointestinal radiologists from three institutions. Each observer assigned a numeric score (1 = poor, 2 = fair, 3 = good, and 4 = excellent) that rated the quality of the radiograph with respect to these characteristics: definition of fold pattern, translucency, distention, and integrity of the barium column. Statistical analysis was performed for each characteristic using Wilcoxon's two-sample rank sum test. All six observers found a statistically significant difference between the two barium formulations for mean scores for definition of fold pattern and translucency. Mean scores for fold pattern were 3.3, 3.0, 3.2, 3.6, 3.3, and 3.4 for Entrobar and 2.1, 2.3, 2.4, 3.2, 2.6, and 2.7 for E-Z-Paque. Mean scores for translucency were 2.5, 2.7, 2.8, 3.1, 2.7, and 3.3 for Entrobar and 1.6, 1.7, 2.1, 2.3, 1.9, and 2.7 for E-Z-Paque. No statistically significant difference was found for mean score for distention or integrity of the barium column. On radiographs, Entrobar was found to have superior characteristics for visualization of fold pattern and translucency but offered no advantages for distention or integrity of the barium column. Improved translucency and definition of fold pattern may translate into improved sensitivity and confidence in diagnosing small-bowel abnormality.

Quasiparticle recombination dynamics in the model cuprate superconductor HgBa2CuO4+δ

NASA Astrophysics Data System (ADS)

Hinton, J. P.; Thewalt, E.; Koralek, J. D.; Orenstein, J.; Barisic, N.; Xhao, X.; Chan, M.; Dorow, C.; Veit, M.; Ji, L.; Greven, M.

2014-03-01

The cuprate family of high temperature superconductors is characterized by a variety of electronic phases which emerge when charge carriers are added to the antiferromagnetic parent compound. The structural simplicity of the single layer cuprate system HgBa2CuO4+δ (Hg1201) is advantageous for experimentally detecting subtle features of these phases. In this work, we investigate the recombination dynamics of photo-excited quasiparticles in Hg1201 as a function of doping, temperature, and magnetic field using pump-probe optical reflectivity. We observe two distinct onset temperatures above TC in the underdoped part of the phase diagram, corresponding to T* and T** as observed in transport and neutron scattering experiments. We also measure a suppression of the recombination rate near TC which peaks at 8% hole concentration. We associate this suppression with coherence effects. Lastly, we observe a complex, non-monotonic temperature dependence in the dynamics around optimal doping, providing evidence for reentrant phase transitions near the apex of the superconducting dome. Work supported by DOE-BES

[Value of preoperative barium contrast examination for the diagnosis and operative planning in gastric cancer].

PubMed

Wang, Chang-jian; Zhao, Guang-fa; Li, Qing-guo; Chen, Jing-gui; Zhu, Kai; Shi, Ying-qiang; Fu, Hong

2010-04-01

To investigate the value of preoperative barium contrast examination for the diagnosis and operative planning in gastric cancer. Clinical data of 229 gastric cancer patients were analyzed retrospectively. Lesions were divided into three parts: the cardiac, the body, and the antrum. The diagnostic accuracy of localization and the extent of tumor between gastroscopy alone and gastroscopy plus barium contrast were compared with the results of surgical findings. The diagnostic accuracy of localization and the extent of tumor for gastroscopy in the cardiac, the body and the antrum cancers were 100% and 78.4%, 94.6% and 86.5%, 98.1% and 84.6%, respectively, while for gastroscopy plus barium contrast were 100% and 84.8%, 100% and 91.9%, 99.0% and 90.4%, respectively. The diagnostic accuracy of both the localization and the extent of tumor were not significantly different between gastroscopy alone and gastroscopy plus barium contrast (P>0.05). Diagnostic accuracy of the length of esophagus infiltrated by cardiac cancer in gastroscopy was 60.6%, while in gastroscopy plus barium contrast was 90.9%, which was significantly different (P<0.05). Gastroscopy plus barium contrast was more accurate in predicting the possibility of thoracotomy in cardiac cancer infiltrating the lower esophagus. It is necessary to perform preoperative barium contrast examination in cardiac cancer patients, so as to identify whether the lower esophagus is infiltrated and to measure the length of lesion, which can provide evidences for making a decision of thoracotomy. For gastric body and antrum cancer, there is no indication for barium contrast examination if gastroscopy findings are satisfied.

Tordo 1 polar cusp barium plasma injection experiment

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

Wescott, E.M.; Stenbaek-Nielsen, H.C.; Davis, T.N.

1978-04-01

In January 1975, two barium plasma injection experiments were carried out with rockets launched from Cape Parry, Northwest Territories, Canada, into the upper atmosphere where field lines from the dayside cusp region intersect the ionosphere. One experiment, Tordo 1, took place near the beginning of a worldwide magnetic storm. It became a polar cap experiment almost immediately as convection perpendicular to B moved the fluorescent plasma jet away from the cusp across the polar cap in an antisunward direction. Convection across the polar cap with an average velocity of more than 1 km/s was observed for nearly 40 min untilmore » the barium flux tubes encountered large E fields associated with a poleward bulge of the auroral oval near Greenland. Prior to the encounter with the aurora near Greenland there is evidence of upward acceleration of the barium ions while they were in the polar cap. The three-dimensional observations of the plasma orientation and motion give an insight into convection from the cusp region across the polar cap, the orientation of the polar cap magnetic field lines out to several earth radii, the causes of polar cap magnetic perturbations, and parallel acceleration processes.« less

Quasi-particles ultrafastly releasing kink bosons to form Fermi arcs in a cuprate superconductor.

PubMed

Ishida, Y; Saitoh, T; Mochiku, T; Nakane, T; Hirata, K; Shin, S

2016-01-05

In a conventional framework, superconductivity is lost at a critical temperature (Tc) because, at higher temperatures, gluing bosons can no longer bind two electrons into a Cooper pair. In high-Tc cuprates, it is still unknown how superconductivity vanishes at Tc. We provide evidence that the so-called ≲ 70-meV kink bosons that dress the quasi-particle excitations are playing a key role in the loss of superconductivity in a cuprate. We irradiated a 170-fs laser pulse on Bi2Sr2CaCu2O(8+δ) and monitored the responses of the superconducting gap and dressed quasi-particles by time- and angle-resolved photoemission spectroscopy. We observe an ultrafast loss of superconducting gap near the d-wave node, or light-induced Fermi arcs, which is accompanied by spectral broadenings and weight redistributions occurring within the kink binding energy. We discuss that the underlying mechanism of the spectral broadening that induce the Fermi arc is the undressing of quasi-particles from the kink bosons. The loss mechanism is beyond the conventional framework, and can accept the unconventional phenomena such as the signatures of Cooper pairs remaining at temperatures above Tc.

Quasi-particles ultrafastly releasing kink bosons to form Fermi arcs in a cuprate superconductor

PubMed Central

Ishida, Y.; Saitoh, T.; Mochiku, T.; Nakane, T.; Hirata, K.; Shin, S.

2016-01-01

In a conventional framework, superconductivity is lost at a critical temperature (Tc) because, at higher temperatures, gluing bosons can no longer bind two electrons into a Cooper pair. In high-Tc cuprates, it is still unknown how superconductivity vanishes at Tc. We provide evidence that the so-called ≲70-meV kink bosons that dress the quasi-particle excitations are playing a key role in the loss of superconductivity in a cuprate. We irradiated a 170-fs laser pulse on Bi2Sr2CaCu2O8+δ and monitored the responses of the superconducting gap and dressed quasi-particles by time- and angle-resolved photoemission spectroscopy. We observe an ultrafast loss of superconducting gap near the d-wave node, or light-induced Fermi arcs, which is accompanied by spectral broadenings and weight redistributions occurring within the kink binding energy. We discuss that the underlying mechanism of the spectral broadening that induce the Fermi arc is the undressing of quasi-particles from the kink bosons. The loss mechanism is beyond the conventional framework, and can accept the unconventional phenomena such as the signatures of Cooper pairs remaining at temperatures above Tc. PMID:26728626

MCrAlY bond coat with enhanced Yttrium layer

DOEpatents

Jablonski, Paul D; Hawk, Jeffrey A

2015-04-21

One or more embodiments relates to an MCrAlY bond coat comprising an MCrAlY layer in contact with a Y--Al.sub.2O.sub.3 layer. The MCrAlY layer is comprised of a .gamma.-M solid solution, a .beta.-MAl intermetallic phase, and Y-type intermetallics. The Y--Al.sub.2O.sub.3 layer is comprised of Yttrium atoms coordinated with oxygen atoms comprising the Al.sub.2O.sub.3 lattice. Both the MCrAlY layer and the Y--Al.sub.2O.sub.3 layer have a substantial absence of Y--Al oxides, providing advantage in the maintainability of the Yttrium reservoir within the MCrAlY bulk. The MCrAlY bond coat may be fabricated through application of a Y.sub.2O.sub.3 paste to an MCrAlY material, followed by heating in a non-oxidizing environment.

Methods for producing monodispersed particles of barium titanate

DOEpatents

Hu, Zhong-Cheng

2001-01-01

The present invention is a low-temperature controlled method for producing high-quality, ultrafine monodispersed nanocrystalline microsphere powders of barium titanate and other pure or composite oxide materials having particles ranging from nanosized to micronsized particles. The method of the subject invention comprises a two-stage process. The first stage produces high quality monodispersed hydrous titania microsphere particles prepared by homogeneous precipitation via dielectric tuning in alcohol-water mixed solutions of inorganic salts. Titanium tetrachloride is used as an inorganic salt precursor material. The second stage converts the pure hydrous titania microsphere particles into crystalline barium titanate microsphere powders via low-temperature, hydrothermal reactions.

Barium and manganese-doped zinc silicate rods prepared by mesoporous template route and their luminescence property

NASA Astrophysics Data System (ADS)

Dang, Lingyan; Tian, Chen; Zhao, Shifeng; Lu, Qingshan

2018-06-01

Barium and manganese-doped zinc silicates was prepared under hydrothermal treatment by mesoporous template route employing mesoporous silica as an active template. The sample displays a rod-like morphology with a mean diameter of ∼40 nm and a mean length of ∼450 nm, which inherits the characteristics of mesoporous silica. The individual rods show single crystalline and assemble into bundle-like hierarchical structure along the channels of the mesoporous silica. When barium ions together with manganese ions are co-doped in zinc silicate, the green emission corresponding to manganese ions display a significant enhancement, especially for the sample with the barium doping concentration of 0.08, which indicates that an energy transfer from barium to manganese ions takes place. With further increasing barium concentration from 0.08 to 0.10, the recombination between the defects related to barium and the excitation states of the manganese dominates accompanying non-radiative transitions which can reduce the emission efficiency.

Preparation and characterization of antimony barium composite oxide photocatalysts

NASA Astrophysics Data System (ADS)

Han, X. P.; Yao, B. H.; Pan, Q. H.; Pen, C.; Zhang, C. L.

2018-01-01

In this paper, two kinds of antimony barium composite oxide photocatalysts have been prepared by two methods and characterized by XRD and SEM. The photocatalytic activity was evaluated by a photocatalytic reactor and an ultraviolet spectrophotometer. The results showed that-BaSb2O5•4H2O, BaSb2O6 two kinds of antimony barium composite oxide photocatalysts were successfully prepared in this experiment and they showed good photocatalytic properties. In addition, BaSb2O6 morphology showed more regular, microstructure and better catalytic performance.

Abscopal Effects and Yttrium-90 Radioembolization

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

Ghodadra, Anish; Bhatt, Sumantha; Camacho, Juan C.

2016-07-15

We present the case of an 80-year-old male with squamous cell carcinoma with bilobar hepatic metastases who underwent targeted Yttrium-90 radioembolization of the right hepatic lobe lesion. Subsequently, there was complete regression of the nontargeted, left hepatic lobe lesion. This may represent the first ever reported abscopal effect in radioembolization. The abscopal effect refers to the phenomenon of tumor response in nontargeted sites after targeted radiotherapy. In this article, we briefly review the immune-mediated mechanisms responsible for the abscopal effect.

Isotope shifts from collinear laser spectroscopy of doubly charged yttrium isotopes

NASA Astrophysics Data System (ADS)

Vormawah, L. J.; Vilén, M.; Beerwerth, R.; Campbell, P.; Cheal, B.; Dicker, A.; Eronen, T.; Fritzsche, S.; Geldhof, S.; Jokinen, A.; Kelly, S.; Moore, I. D.; Reponen, M.; Rinta-Antila, S.; Stock, S. O.; Voss, A.

2018-04-01

Collinear laser spectroscopy has been performed on doubly charged ions of radioactive yttrium in order to study the isotope shifts of the 294.6-nm 5 s 1/2 2S →5 p 1/2 2P line. The potential of such an alkali-metal-like transition to improve the reliability of atomic-field-shift and mass-shift factor calculations, and hence the extraction of nuclear mean-square radii, is discussed. Production of yttrium ion beams for such studies is available at the IGISOL IV Accelerator Laboratory, Jyväskylä, Finland. This newly recommissioned facility is described here in relation to the on-line study of accelerator-produced short-lived isotopes using collinear laser spectroscopy and application of the technique to doubly charged ions.

The influence of implanted yttrium on the cyclic oxidation behaviour of 304 stainless steel

NASA Astrophysics Data System (ADS)

Riffard, F.; Buscail, H.; Caudron, E.; Cueff, R.; Issartel, C.; Perrier, S.

2006-03-01

High-temperature alloys are frequently used in power plants, gasification systems, petrochemical industry, combustion processes and in aerospace applications. Depending on the application, materials are subjected to corrosive atmospheres and thermal cycling. In the present work, thermal cycling was carried out in order to study the influence of implanted yttrium on the oxide scale adherence on 304 steel specimens oxidised in air at 1273 K. In situ X-ray diffraction indicates that the oxides formed at 1273 K are different on blank specimens compared to implanted specimens. Glancing angle XRD allows to analyse the oxide scale composition after cooling to room temperature. Experimental results show that yttrium implantation at a nominal dose of 10 17 ions cm -2 does not improve significantly the cyclic oxidation behaviour of the austenitic AISI 304 steel. However, it appears that yttrium implantation remarkably enhance the oxidation resistance during isothermal oxidation. It reduces the transient oxidation stage and the parabolic oxidation rate constant by one order of magnitude.

Colonoscopy can miss diverticula of the left colon identified by barium enema

PubMed Central

Niikura, Ryota; Nagata, Naoyoshi; Shimbo, Takuro; Akiyama, Junichi; Uemura, Naomi

2013-01-01

AIM: To identify the diagnostic value of colonoscopy for diverticulosis as determined by barium enema. METHODS: A total of 65 patients with hematochezia who underwent colonoscopy and barium enema were analyzed, and the diagnostic value of colonoscopy for diverticula was assessed. The receiver operating characteristic area under the curve was compared in relation to age (< 70 or ≥ 70 years), sex, and colon location. The number of diverticula was counted, and the detection ratio was calculated. RESULTS: Colonic diverticula were observed in 46 patients with barium enema. Colonoscopy had a sensitivity of 91% and specificity of 90%. No significant differences were found in the receiver operating characteristic area under the curve (ROC-AUC) for age group or sex. The ROC-AUC of the left colon was significantly lower than that of the right colon (0.81 vs 0.96, P = 0.02). Colonoscopy identified 486 colonic diverticula, while barium enema identified 1186. The detection ratio for the entire colon was therefore 0.41 (486/1186). The detection ratio in the left colon (0.32, 189/588) was significantly lower than that of the right colon (0.50, 297/598) (P < 0.01). CONCLUSION: Compared with barium enema, only half the number of colonic diverticula can be detected by colonoscopy in the entire colon and even less in the left colon. PMID:23613630

Colonoscopy can miss diverticula of the left colon identified by barium enema.

PubMed

Niikura, Ryota; Nagata, Naoyoshi; Shimbo, Takuro; Akiyama, Junichi; Uemura, Naomi

2013-04-21

To identify the diagnostic value of colonoscopy for diverticulosis as determined by barium enema. A total of 65 patients with hematochezia who underwent colonoscopy and barium enema were analyzed, and the diagnostic value of colonoscopy for diverticula was assessed. The receiver operating characteristic area under the curve was compared in relation to age (< 70 or ≥ 70 years), sex, and colon location. The number of diverticula was counted, and the detection ratio was calculated. Colonic diverticula were observed in 46 patients with barium enema. Colonoscopy had a sensitivity of 91% and specificity of 90%. No significant differences were found in the receiver operating characteristic area under the curve (ROC-AUC) for age group or sex. The ROC-AUC of the left colon was significantly lower than that of the right colon (0.81 vs 0.96, P = 0.02). Colonoscopy identified 486 colonic diverticula, while barium enema identified 1186. The detection ratio for the entire colon was therefore 0.41 (486/1186). The detection ratio in the left colon (0.32, 189/588) was significantly lower than that of the right colon (0.50, 297/598) (P < 0.01). Compared with barium enema, only half the number of colonic diverticula can be detected by colonoscopy in the entire colon and even less in the left colon.

High Temperature Evolution of PtNiAl-Based Thermal Barrier Coatings from First Principles Simulations

DTIC Science & Technology

2010-08-29

intergranular film, reminiscent of yttrium- aluminum - garnet , was presented. Such films tend to increase stability of the ceramic. Thus, as in the...and for grain boundaries doped with a series of early transition metals, as well as with barium, gadolinium , and neodymium. We predicted that the

Evaluating the improvement of corrosion residual strength by adding 1.0 wt.% yttrium into an AZ91D magnesium alloy

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

Wang Qiang; Liu Yaohui, E-mail: liuyaohui2005@yahoo.com; Fang Shijie

2010-06-15

The influence of yttrium on the corrosion residual strength of an AZ91D magnesium alloy was investigated detailedly. Scanning electron microscope was employed to analyze the microstructure and the fractography of the studied alloys. The microstructure of AZ91D magnesium alloy is remarkably refined due to the addition of yttrium. The electrochemical potentiodynamic polarization curve of the studied alloy was performed with a CHI 660b electrochemical station in the three-electrode system. The result reveals that yttrium significantly promotes the overall corrosion resistance of AZ91D magnesium alloy by suppressing the cathodic reaction in corrosion process. However, the nucleation and propagation of corrosion pitsmore » on the surface of the 1.0 wt.% Y modified AZ91D magnesium alloy indicate that pitting corrosion still emerges after the addition of yttrium. Furthermore, stress concentration caused by corrosion pits should be responsible for the drop of corrosion residual strength although the addition of yttrium remarkably weakens the effect of stress concentration at the tip of corrosion pits in loading process.« less

Ultrafast photoconductivity of undoped cuprates

NASA Astrophysics Data System (ADS)

Dodge, J. Steven; Farahani, Amir; Petersen, Jesse; Liang, Ruixing; Bozovic, Ivan

2010-03-01

Using a visible pump-THz probe technique, we studied the ultrafast transient photoconductivity of the insulating cuprate La2CuO4, and compared it with earlier measurements of Sr2CuO2Cl2 and YBa2Cu3O6. In all these compounds, we observe a rapid onset of photoconductivity that is followed by a non-exponential relaxation on a picosecond time scales, the dynamics of which are independent of photocarrier concentration ranging from 0.2 to 1.5 percent. The photoconductivity decay is qualitatively similar to the decay of the photoinduced gap absorption in Sr2CuO2Cl2,footnotetextJ. S. Dodge, arXiv:0910.5048 indicating a common origin for the two effects. Assuming a quantum efficiency of unity, the estimated peak mobility for all three compounds is within 0.1-0.4 cm^2/V.s; this is lower than the Hall mobility in chemically doped systems with similar carrier concentrations,footnotetext Ando et al, Phys. Rev. Lett. 87, 017001 (2001) but orders of magnitude larger than earlier DC photoconductivity results.footnotetextThio et al, Phys. Rev. B 42, 10800 (1990) The similarity of the peak photoconductivity across three different compounds indicates that it is an intrinsic feature of the copper oxide plane.

Efficacy of Barium-Based Fecal Tagging for CT Colonography: a Comparison between the Use of High and Low Density Barium Suspensions in a Korean Population - a Preliminary Study

PubMed Central

Kim, Min Ju; Lee, Seung Soo; Byeon, Jeong-Sik; Choi, Eugene K.; Kim, Jung Hoon; Kim, Yeoung Nam; Kim, Ah Young; Ha, Hyun Kwon

2009-01-01

Objective This preliminarily study was designed to determine and to compare the efficacy of two commercially available barium-based fecal tagging agents for CT colonography (CTC) (high-density [40% w/v] and low-density [4.6% w/v] barium suspensions) in a population in Korea. Materials and Methods In a population with an identified with an average-risk for colorectal cancer, 15 adults were administered three doses of 20 ml 40% w/v barium for fecal tagging (group I) and 15 adults were administered three doses of 200 ml 4.6% w/v barium (group II) for fecal tagging. Excluding five patients in group I and one patient in group II that left the study, ten patients in group I and 14 patients in group II were finally included in the analysis. Two experienced readers evaluated the CTC images in consensus regarding the degree of tagging of stool pieces 6 mm or larger. Stool pieces were confirmed with the use of standardized CTC criteria or the absence of matched lesions as seen on colonoscopy. The rates of complete fecal tagging were analyzed on a per-lesion and a per-segment basis and were compared between the patients in the two groups. Results Per-lesion rates of complete fecal tagging were 52% (22 of 42; 95% CI, 37.7-66.6%) in group I and 78% (28 of 36; 95% CI, 61.7-88.5%) in group II. The difference between the two groups did not reach statistical significance (p = 0.285). The per-segment rates of complete tagging were 33% (6 of 18; 95% CI, 16.1%-56.4%) in group I and 60% (9 of 15; 95% CI, 35.7%-80.3%) in group II; again, the difference between the two groups did not reach statistical significance (p = 0.171). Conclusion Barium-based fecal tagging using both the 40% w/v and the 4.6% w/v barium suspensions showed moderate tagging efficacy. The preliminary comparison did not demonstrate a statistically significant difference in the tagging efficacy between the use of the two tagging agents, despite the tendency toward better tagging with the use of the 4.6% w/v barium

PRELIMINARY STUDIES OF THE GASTROINTESTINAL TRACT WITH COLLOIDAL BARIUM

PubMed Central

Windholz, Frank; Kaplan, Henry S.; Jones, Henry H.

1951-01-01

A stable colloidal suspension of barium sulfate has been developed and tested in roentgen examination of the gastrointestinal tract. The new material is rather distinctive in radiographic appearance and can usually be differentiated from simple barium-water mixtures by inspection of roentgenograms of the opacified stomach and small intestine. It usually affords a satisfactory demonstration of the mucosal folds of the stomach and duodenal bulb and is considerably more resistant to flocculation and precipitation by retained gastric secretions. In the small intestine, it has little tendency to undergo flocculation and fragmentation, and permits visualization of fine mucosal configurations with unusual clarity. Its motility is about the same as that of conventional suspensions. Air contrast colon examinations with the colloidal preparation exhibit a very uniform, opaque, and stable coating of the bowel wall and are more consistently satisfactory than when simple barium-water mixtures are used. ImagesFigure 1.Figure 1.Figure 1.Figure 1.Figure 2.Figure 2.Figure 3.Figure 4.Figure 4.Figure 5.Figure 5.Figure 6. PMID:14812347

Hydrothermal synthesis, crystal structures and photoluminescence properties of mixed europium-yttrium organic frameworks

NASA Astrophysics Data System (ADS)

Han, Yinfeng; Fu, Lianshe; Mafra, Luís; Shi, Fa-Nian

2012-02-01

Three mixed europium-yttrium organic frameworks: Eu2-xYx(Mel)(H2O)6 (Mel=mellitic acid or benzene-1,2,3,4,5,6-hexacarboxylic acid, x=0.38 1, 0.74 2, and 0.86 3) have been synthesized and characterized. All the compounds contain a 3-D net with (4, 8)-flu topology. The study indicates that the photoluminescence properties are effectively affected by the different ratios of europium and yttrium ions, the quantum efficiency is increased and the Eu3+ lifetime becomes longer in these MOFs than those of the Eu analog.

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

Parab, Niranjan D.; Hudspeth, Matthew; Claus, Ben

Granular materials are widely used to resist impact and blast. Under these dynamic loadings, the constituent particles in the granular system fracture. To study the fracture mechanisms in brittle particles under dynamic compressive loading, a high speed X-ray phase contrast imaging setup was synchronized with a Kolsky bar apparatus. Controlled compressive loading was applied on two contacting particles using the Kolsky bar apparatus and fracture process was captured using the high speed X-ray imaging setup. Five different particles were investigated: soda-lime glass, polycrystalline silica (silicon dioxide), polycrystalline silicon, barium titanate glass, and yttrium stabilized zirconia. For both soda lime glassmore » and polycrystalline silica particles, one of the particles fragmented explosively, thus breaking into many small pieces. For Silicon and barium titanate glass particles, a finite number of cracks were observed in one of the particles causing it to fracture. For yttrium stabilized zirconia particles, a single meridonial crack developed in one of the particles, breaking it into two parts.« less

Universal intrinsic scale of the hole concentration in high- Tc cuprates

NASA Astrophysics Data System (ADS)

Honma, T.; Hor, P. H.; Hsieh, H. H.; Tanimoto, M.

2004-12-01

We have measured thermoelectric power (TEP) as a function of hole concentration per CuO2 layer Ppl in Y1-xCaxBa2Cu3O6 (Ppl=x/2) with no oxygen in the Cu-O chain layer. The room-temperature TEP as a function of Ppl , S290(Ppl) , of Y1-xCaxBa2Cu3O6 behaves identically to that of La2-zSrzCuO4 (Ppl=z) . We argue that S290(Ppl) represents a measure of the intrinsic equilibrium electronic states of doped holes and, therefore, can be used as a common scale for the carrier concentrations of layered cuprates. We shows that the Ppl determined by this new universal scale is consistent with both hole concentration microscopically determined by NQR and the hole concentration macroscopically determined by the formal valency of Cu . We find two characteristic scaling temperatures, TS* and TS2* , in the TEP versus temperature curves that change systematically with doping. Based on the universal scale, we uncover a universal phase diagram in which almost all the experimentally determined pseudogap temperatures as a function of Ppl fall on two common curves; lower pseudogap temperature defined by the TS* versus Ppl curve and upper pseudogap temperature defined by the TS2* versus Ppl curve. We find that while pseudogaps are intrinsic properties of doped holes of a single CuO2 layer for all high- Tc cuprates, Tc depends on the number of layers, therefore, the inter layer coupling, in each individual system.

Observation and theory of the barium releases from the CRRES satellite

NASA Technical Reports Server (NTRS)

Bernhardt, P. A.; Huba, J. D.; Scales, W. A.; Wescott, E. M.; Stenbaek-Nielsen, H. C.

1992-01-01

The relationship between releases of barium from the NASA Combined Release and Radiation Effects Satellite (CRRES) and enhanced auroral activity is discussed with reference to observational data. Barium releases were conducted at a variety of altitudes and injection velocities, and plasma irregularities are reported as a result of the interactions. Auroral activity increased within 5 min of each release, and references are made to the effects on diamagnetic cavities, bulk ion motion, and stimulated electron and ion precipitation. Artificially created structured diamagnetic cavities are noted for each release, plasma waves are generated by the high-speed ion clouds, and enhanced ionization is found in the critical ionization-velocity process. Barium releases are effective in stimulating electron precipitation, and the observed irregularities are related to cycloid bunching of the initial ion distributions.

Fabrication of dense yttrium oxyfluoride ceramics by hot pressing and their mechanical, thermal, and electrical properties

NASA Astrophysics Data System (ADS)

Tahara, Ryuki; Tsunoura, Toru; Yoshida, Katsumi; Yano, Toyohiko; Kishi, Yukio

2018-06-01

Excellent corrosion-resistant materials have been strongly required to reduce particle contamination during the plasma process in semiconductor production. Yttrium oxyfluoride can be a candidate as highly corrosion-resistant material. In this study, three types of dense yttrium oxyfluoride ceramics with different oxygen contents, namely, YOF, Y5O4F7 and Y5O4F7 + YF3, were fabricated by hot pressing, and their mechanical, thermal, and electrical properties were evaluated. Y5O4F7 ceramics showed an excellent thermal stability up to 800 °C, a low loss factor, and volume resistivity comparable to conventional plasma-resistant oxides, such as Y2O3. From these results, yttrium oxyfluoride ceramics are strongly suggested to be used as electrostatic chucks in semiconductor production.

Comparison of bolus transit patterns identified by esophageal impedance to barium esophagram in patients with dysphagia.

PubMed

Cho, Y K; Choi, M-G; Oh, S N; Baik, C N; Park, J M; Lee, I S; Kim, S W; Choi, K Y; Chung, I-S

2012-01-01

Bolus transit through the esophagus has not been validated by videoesophagram in patients with dysphagia and changes in impedance with abnormal barium transit have not been described in those patients. The aim of this study was to compare esophageal impedance findings with barium esophagram measurements in patients with dysphagia. The consecutive patients with dysphagia underwent conventional multichannel esophageal impedance manometry, after which a barium videoesophagram was performed simultaneously with multichannel esophageal impedance manometry using a mean of three swallows of barium. Esophageal emptying patterns shown in the esophagogram were classified by the degree of intraesophageal stasis and presence of intraesophageal reflux. Bolus transit patterns in impedance were classified as complete and incomplete transit. Sixteen patients (M : F = 8 : 8, mean age, 47 years) were enrolled. Their manometric diagnosis were normal (n= 6), ineffective esophageal motility (n= 1), diffuse esophageal spasm (DES; n= 2), and achalasia (n= 7). Sixty-three swallows were analyzed. According to impedance analysis, 21/22 swallows with normal barium emptying showed complete transit (96%) and 31/32 swallows with severe stasis showed incomplete transit (97%). Nine swallows with mild stasis showed either complete or incomplete transit patterns in impedance. Swallows with mild barium stasis and complete transit in impedance were observed in patients who had received treatment (two patients with achalasia with history of esophageal balloonplasty and a patient with DES after nifedipine administration). Impedance reflected severe stasis with retrograde barium movement and described typical bolus transit patterns in patients with achalasia and DES. In conclusion, impedance-barium esophagram concordance is high for swallows with normal esophageal emptying and for severe barium stasis in patients with dysphagia. © 2011 Copyright the Authors. Journal compilation © 2011, Wiley

Bosonic excitations and electron pairing in an electron-doped cuprate superconductor

NASA Astrophysics Data System (ADS)

Wang, M. C.; Yu, H. S.; Xiong, J.; Yang, Y.-F.; Luo, S. N.; Jin, K.; Qi, J.

2018-04-01

By applying ultrafast optical spectroscopy to electron-doped La1.9Ce0.1CuO4 ±δ , we discern a bosonic mode of electronic origin and provide the evolution of its coupling with the charge carriers as a function of temperature. Our results show that it has the strongest coupling strength near Tc and can fully account for the superconducting pairing. This mode can be associated with the two-dimensional antiferromagnetic spin correlations emerging below a critical temperature T† larger than Tc. Our work may help to establish a quantitative relation between bosonic excitations and superconducting pairing in electron-doped cuprates.

Comparison of barium swallow and ultrasound in diagnosis of gastro-oesophageal reflux in children.

PubMed Central

Naik, D R; Bolia, A; Moore, D J

1985-01-01

Fifty one infants and older children with suspected gastro-oesophageal reflux entered a study comparing the diagnostic accuracy of a standard barium swallow examination with that of ultrasound scanning. All children were examined by both techniques. In 40 cases there was unequivocal agreement between the examinations. Of the remaining patients, four had definite reflux by ultrasonic criteria but showed no evidence of reflux on barium swallow examination, four had positive findings on ultrasound but showed only minimal reflux on barium swallow, and one showed minimal reflux on ultrasound but had a negative barium meal result. In two children the ultrasound study was inconclusive. Ultrasound has an important role in the diagnosis and follow up of patients under the age of 5 years with gastro-oesophageal reflux. Images FIG 1 FIG 2 PMID:3924317

Quasiparticle density of states, localization, and distributed disorder in the cuprate superconductors

NASA Astrophysics Data System (ADS)

Sulangi, Miguel Antonio; Zaanen, Jan

2018-04-01

We explore the effects of various kinds of random disorder on the quasiparticle density of states of two-dimensional d -wave superconductors using an exact real-space method, incorporating realistic details known about the cuprates. Random on-site energy and pointlike unitary impurity models are found to give rise to a vanishing DOS at the Fermi energy for narrow distributions and low concentrations, respectively, and lead to a finite, but suppressed, DOS at unrealistically large levels of disorder. Smooth disorder arising from impurities located away from the copper-oxide planes meanwhile gives rise to a finite DOS at realistic impurity concentrations. For the case of smooth disorder whose average potential is zero, a resonance is found at zero energy for the quasiparticle DOS at large impurity concentrations. We discuss the implications of these results on the computed low-temperature specific heat, the behavior of which we find is strongly affected by the amount of disorder present in the system. We also compute the localization length as a function of disorder strength for various types of disorder and find that intermediate- and high-energy states are quasiextended for low disorder, and that states near the Fermi energy are strongly localized and have a localization length that exhibits an unusual dependence on the amount of disorder. We comment on the origin of disorder in the cuprates and provide constraints on these based on known results from scanning tunneling spectroscopy and specific heat experiments.

Processing of Superconductor-Normal-Superconductor Josephson Edge Junctions

NASA Technical Reports Server (NTRS)

Kleinsasser, A. W.; Barner, J. B.

1997-01-01

The electrical behavior of epitaxial superconductor-normal-superconductor (SNS) Josephson edge junctions is strongly affected by processing conditions. Ex-situ processes, utilizing photoresist and polyimide/photoresist mask layers, are employed for ion milling edges for junctions with Yttrium-Barium-Copper-Oxide (YBCO) electrodes and primarily Co-doped YBCO interlayers.

Comparison of Calcium and Barium Microcapsules as Scaffolds in the Development of Artificial Dermal Papillae.

PubMed

Liu, Yang; Lin, Changmin; Zeng, Yang; Li, Haihong; Cai, Bozhi; Huang, Keng; Yuan, Yanping; Li, Yu

2016-01-01

This study aimed to develop and evaluate barium and calcium microcapsules as candidates for scaffolding in artificial dermal papilla. Dermal papilla cells (DPCs) were isolated and cultured by one-step collagenase treatment. The DPC-Ba and DPC-Ca microcapsules were prepared by using a specially designed, high-voltage, electric-field droplet generator. Selected microcapsules were assessed for long-term inductive properties with xenotransplantation into Sprague-Dawley rat ears. Both barium and calcium microcapsules maintained xenogenic dermal papilla cells in an immunoisolated environment and induced the formation of hair follicle structures. Calcium microcapsules showed better biocompatibility, permeability, and cell viability in comparison with barium microcapsules. Before 18 weeks, calcium microcapsules gathered together, with no substantial immune response. After 32 weeks, some microcapsules were near inflammatory cells and wrapped with fiber. A few large hair follicles were found. Control samples showed no marked changes at the implantation site. Barium microcapsules were superior to calcium microcapsules in structural and mechanical stability. The cells encapsulated in hydrogel barium microcapsules exhibited higher short-term viability. This study established a model to culture DPCs in 3D culture conditions. Barium microcapsules may be useful in short-term transplantation study. Calcium microcapsules may provide an effective scaffold for the development of artificial dermal papilla.

Barium Tagging n Solid Xenon for nEXO Neutrinoless Double Beta Decay

NASA Astrophysics Data System (ADS)

Walton, Tim; Chambers, Chris; Craycraft, Adam; Fairbank, William; nEXO Collaboration

2015-04-01

nEXO is a next-generation experiment designed to search for neutrinoless double beta decay of the isotope Xe136 in a liquid xenon time projection chamber. Positive observation of this decay would determine the nature of the neutrino to be a Majorana particle. Since the daughter of this decay is barium (Ba136), detecting the presence of Ba136 at a decay site (called ``barium tagging'') would provide strong rejection of backgrounds in the search for this decay. This would involve detecting a single barium ion from within a macroscopic volume of liquid xenon. This technique may be available for a second phase of the nEXO detector and sensitivity beyond the inverted hierarchy to neutrino oscillations. Several methods of barium tagging are being explored by the nEXO collaboration, but here we present a method of trapping the barium ion/atom (it may neutralize) in solid xenon (SXe) at the end of a cold probe, and then detecting the ion/atom by its fluorescence in the SXe. Our group at CSU has been studying the fluorescence of Ba in SXe by laser excitation, in order to ultimately detect a single Ba +/Ba in a SXe sample. We present studies of fluorescence signals, as well as recent results on imaging small numbers of Ba atoms in SXe, in a focused laser region. This work is supported by grants from the National Science Foundation and the Department of Energy.

Effect of barium-coated halloysite nanotube addition on the cytocompatibility, mechanical and contrast properties of poly(methyl methacrylate) cement.

PubMed

Jammalamadaka, Uday; Tappa, Karthik; Weisman, Jeffery A; Nicholson, James Connor; Mills, David K

2017-01-01

Halloysite nanotubes (HNTs) were investigated as a platform for tunable nanoparticle composition and enhanced opacity in poly(methyl methacrylate) (PMMA) bone cement. Halloysite has been widely used to increase the mechanical properties of various polymer matrices, in stark contrast to other fillers such as barium sulfate that provide opacity but also decrease mechanical strength. The present work describes a dry deposition method for successively fabricating barium sulfate nanoparticles onto the exterior surface of HNTs. A sintering process was used to coat the HNTs in barium sulfate. Barium sulfate-coated HNTs were then added to PMMA bone cement and the samples were tested for mechanical strength and tailored opacity correlated with the fabrication ratio and the amount of barium sulfate-coated HNTs added. The potential cytotoxic effect of barium-coated HNTs in PMMA cement was also tested on osteosarcoma cells. Barium-coated HNTs were found to be completely cytocompatible, and cell proliferation was not inhibited after exposure to the barium-coated HNTs embedded in PMMA cement. We demonstrate a simple method for the creation of barium-coated nanoparticles that imparted improved contrast and material properties to native PMMA. An easy and efficient method for coating clay nanotubes offers the potential for enhanced imaging by radiologists or orthopedic surgeons.

Use of barium-strontium carbonatite for flux welding and surfacing of mining machines

NASA Astrophysics Data System (ADS)

Kryukov, R. E.; Kozyrev, N. A.; Usoltsev, A. A.

2017-09-01

The results of application of barium-strontium carbonatite for modifying and refining iron-carbon alloys, used for welding and surfacing in ore mining and smelting industry, are generalized. The technology of manufacturing a flux additive containing 70 % of barium-strontium carbonatite and 30 % of liquid glass is proposed. Several compositions of welding fluxes based on silicomanganese slag were tested. The flux additive was introduced in an amount of 1, 3, 5 %. Technological features of welding with the application of the examined fluxes are determined. X-ray spectral analysis of the chemical composition of examined fluxes, slag crusts and weld metal was carried out, as well as metallographic investigations of welded joints. The principal possibility of applying barium-strontium carbonatite as a refining and gas-protective additive for welding fluxes is shown. The use of barium-strontium carbonatite reduces the contamination of the weld seam with nonmetallic inclusions: non-deforming silicates, spot oxides and brittle silicates, and increases the desulfurizing capacity of welding fluxes.

Hydrothermal synthesis, crystal structures and photoluminescence properties of mixed europium-yttrium organic frameworks

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

Han Yinfeng; Department of Chemistry and Environmental Science, Taishan University, Taian 271021; Fu Lianshe

Three mixed europium-yttrium organic frameworks: Eu{sub 2-x}Y{sub x}(Mel)(H{sub 2}O){sub 6} (Mel=mellitic acid or benzene-1,2,3,4,5,6-hexacarboxylic acid, x=0.38 1, 0.74 2, and 0.86 3) have been synthesized and characterized. All the compounds contain a 3-D net with (4, 8)-flu topology. The study indicates that the photoluminescence properties are effectively affected by the different ratios of europium and yttrium ions, the quantum efficiency is increased and the Eu{sup 3+} lifetime becomes longer in these MOFs than those of the Eu analog. - Graphical abstract: Three mixed europium and yttrium organic frameworks: Eu{sub 2-x}Y{sub x}(Mel)(H{sub 2}O){sub 6} (Mel=mellitic acid) have been synthesized and characterized.more » All the compounds contain a 3-D net with (4, 8)-flu topology. The study indicates that the photoluminescence properties are effectively affected by the different ratios of europium and yttrium ions, the quantum efficiency is increased and the Eu{sup 3+} lifetime becomes longer in these MOFs than those of the Eu analog. Highlights: Black-Right-Pointing-Pointer Three (4, 8)-flu topological mixed Eu and Y MOFs were synthesized under mild conditions. Black-Right-Pointing-Pointer Metal ratios were refined by the single crystal data consistent with the EDS analysis. Black-Right-Pointing-Pointer Mixed Eu and Y MOFs show longer lifetime and higher quantum efficiency than the Eu analog. Black-Right-Pointing-Pointer Adding inert lanthanide into luminescent MOFs enlarges the field of luminescent MOFs.« less

Pseudogap-generated a coexistence of Fermi arcs and Fermi pockets in cuprate superconductors

NASA Astrophysics Data System (ADS)

Zhao, Huaisong; Gao, Deheng; Feng, Shiping

2017-03-01

One of the most intriguing puzzle is why there is a coexistence of Fermi arcs and Fermi pockets in the pseudogap phase of cuprate superconductors? This puzzle is calling for an explanation. Based on the t - J model in the fermion-spin representation, the coexistence of the Fermi arcs and Fermi pockets in cuprate superconductors is studied by taking into account the pseudogap effect. It is shown that the pseudogap induces an energy band splitting, and then the poles of the electron Green's function at zero energy form two contours in momentum space, however, the electron spectral weight on these two contours around the antinodal region is gapped out by the pseudogap, leaving behind the low-energy electron spectral weight only located at the disconnected segments around the nodal region. In particular, the tips of these disconnected segments converge on the hot spots to form the closed Fermi pockets, generating a coexistence of the Fermi arcs and Fermi pockets. Moreover, the single-particle coherent weight is directly related to the pseudogap, and grows linearly with doping. The calculated result of the overall dispersion of the electron excitations is in qualitative agreement with the experimental data. The theory also predicts that the pseudogap-induced peak-dip-hump structure in the electron spectrum is absent from the hot-spot directions.

Magnetic proximity effect at the interface between a cuprate superconductor and an oxide spin valve

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

Ovsyannikov, G. A., E-mail: gena@hitech.cplire.ru; Demidov, V. V.; Khaydukov, Yu. N.

2016-04-15

A heterostructure that consists of the YBa{sub 2}Cu{sub 3}O{sub 7–δ} cuprate superconductor and the SrRuO{sub 3}/La{sub 0.7}Sr{sub 0.3}MnO{sub 3} ruthenate/manganite spin valve is investigated using SQUID magnetometry, ferromagnetic resonance, and neutron reflectometry. It is shown that a magnetic moment is induced due to the magnetic proximity effect in the superconducting part of the heterostructure, while the magnetic moment in the composite ferromagnetic interlayer is suppressed. The magnetization emerging in the superconductor coincides in order of magnitude with the results of calculations taking into account the induced magnetic moment of Cu atoms because of orbital reconstruction at the interface between themore » superconductor and the ferromagnet, as well as with the results of the model taking into account the variations in the density of states at a distance on the order of the coherence length in the superconductor. The experimentally obtained characteristic penetration depth of the magnetic moment in the superconductor considerably exceeds the coherence length of the cuprate superconductor, which indicates the predominance of the mechanism of induced magnetic moment of Cu atoms.« less

Short range smectic order driving long range nematic order: Example of cuprates

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

Markiewicz, R. S.; Lorenzana, J.; Seibold, G.

We present a model for describing the combined presence of nematic and ‘smectic’ or stripe-like orders seen in recent scanning tunneling microscopy (STM) experiments on cuprates. The smectic order is treated as an electronic charge density wave with an associated Peierls distortion or a ‘Pomeranchuk wave’. This primary order is restricted to nanoscale domains by disorder effects, while the secondary coupling to strain generates the nematic order with a considerably longer range. Lastly, a variety of experimental results are shown to be consistent with our theoretical predictions.

Short range smectic order driving long range nematic order: Example of cuprates

DOE PAGES

Markiewicz, R. S.; Lorenzana, J.; Seibold, G.; ...

2016-01-27

We present a model for describing the combined presence of nematic and ‘smectic’ or stripe-like orders seen in recent scanning tunneling microscopy (STM) experiments on cuprates. The smectic order is treated as an electronic charge density wave with an associated Peierls distortion or a ‘Pomeranchuk wave’. This primary order is restricted to nanoscale domains by disorder effects, while the secondary coupling to strain generates the nematic order with a considerably longer range. Lastly, a variety of experimental results are shown to be consistent with our theoretical predictions.

Dense nanocrystalline yttrium iron garnet films formed at room temperature by aerosol deposition

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

Johnson, Scooter D., E-mail: scooter.johnson@nrl.navy.mil; Glaser, Evan R.; Cheng, Shu-Fan

Highlights: • We deposit yttrium iron garnet films at room temperature using aerosol deposition. • Films are 96% of theoretical density for yttrium iron garnet. • We report magnetic and structural properties post-deposition and post-annealing. • Low-temperature annealing decreases the FMR linewidth. • We discuss features of the FMR spectra at each anneal temperature. - Abstract: We have employed aerosol deposition to form polycrystalline yttrium iron garnet (YIG) films on sapphire at room temperature that are 90–96% dense. We characterize the structural and dynamic magnetic properties of the dense films using scanning electron microscopy, X-ray diffraction, and ferromagnetic resonance techniques.more » We find that the as-deposited films are pure single-phase YIG formed of compact polycrystallites ∼20 nm in size. The ferromagnetic resonance mode occurs at 2829 G with a linewidth of 308 G. We perform a series of successive anneals up to 1000 °C on a film to explore heat treatment on the ferromagnetic resonance linewidth. We find the narrowest linewidth of 98 G occurs after a 750 °C anneal.« less

Nodal bilayer-splitting controlled by spin-orbit interactions in underdoped high-T c cuprates

DOE PAGES

Harrison, N.; Ramshaw, B. J.; Shekhter, A.

2015-06-03

The highest superconducting transition temperatures in the cuprates are achieved in bilayer and trilayer systems, highlighting the importance of interlayer interactions for high T c. It has been argued that interlayer hybridization vanishes along the nodal directions by way of a specific pattern of orbital overlap. Recent quantum oscillation measurements in bilayer cuprates have provided evidence for a residual bilayer-splitting at the nodes that is sufficiently small to enable magnetic breakdown tunneling at the nodes. Here we show that several key features of the experimental data can be understood in terms of weak spin-orbit interactions naturally present in bilayer systems,more » whose primary effect is to cause the magnetic breakdown to be accompanied by a spin flip. These features can now be understood to include the equidistant set of three quantum oscillation frequencies, the asymmetry of the quantum oscillation amplitudes in c-axis transport compared to ab-plane transport, and the anomalous magnetic field angle dependence of the amplitude of the side frequencies suggestive of small effective g-factors. We suggest that spin-orbit interactions in bilayer systems can further affect the structure of the nodal quasiparticle spectrum in the superconducting phase. PACS numbers: 71.45.Lr, 71.20.Ps, 71.18.+y« less

Phase transition studies in barium and strontium titanates at microwave frequencies

NASA Technical Reports Server (NTRS)

Dahiya, Jai N.

1993-01-01

The objectives were the following: to understand the phase transformations in barium and strontium titanates as the crystals go from one temperature to the other; and to study the dielectric behavior of barium and strontium titanate crystals at a microwave frequency of 9.12 GHz and as a function of temperature. Phase transition studies in barium and strontium titanate are conducted using a cylindrical microwave resonant cavity as a probe. The cavity technique is quite successful in establishing the phase changes in these crystals. It appears that dipole relaxation plays an important role in the behavior of the dielectric response of the medium loading the cavity as phase change takes place within the sample. The method of a loaded resonant microwave cavity as applied in this work has proven to be sensitive enough to monitor small phase changes of the cavity medium.

Exposure to hazardous substances in Cathode Ray Tube (CRT) recycling sites in France

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

Lecler, Marie-Thérèse, E-mail: marie-therese.lecler@inrs.fr; Zimmermann, François; Silvente, Eric

Highlights: • Chemical risks were assessed in the nine cathode ray tube screens recycling facilities. • The main hazardous agents are dust containing lead, cadmium, barium and yttrium. • Exposure and pollutant levels are described for different operations and processes. • All the operations and processes are concerned by significant levels of pollutants. • We suggest recommendations to reduce chemical risk. - Abstract: The Waste Electrical and Electronic Equipment (WEEE) or e-waste recycling sector has grown considerably in the last fifteen years due to the ever shorter life cycles of consumables and an increasingly restrictive policy context. Cathode Ray Tubesmore » (CRTs) from used television and computer screens represent one of the main sources of e-waste. CRTs contain toxic materials such as lead, cadmium, barium, and fluorescent powders which can be released if recycling of CRTs is not appropriate. Exposure to these harmful substances was assessed in nine workshops where CRT screens are treated. Particulate exposure levels were measured using a gravimetric method and metals were analysed by plasma emission spectrometry. The maximum levels of worker exposure were 8.8 mg/m{sup 3}, 1504.3 μg/m{sup 3}, 434.9 μg/m{sup 3}, 576.3 μg/m{sup 3} and 2894.3 μg/m{sup 3} respectively for inhalable dust, barium, cadmium, lead and yttrium. The maximum levels of airborne pollutants in static samples were 39.0 mg/m{sup 3}, 848.2 μg/m{sup 3}, 698.4 μg/m{sup 3}, 549.3 μg/m{sup 3} and 3437.9 μg/m{sup 3} for inhalable dust, barium, cadmium, lead and yttrium. The most harmful operations were identified, and preventive measures for reducing the chemical risk associated with screen recycling were proposed. Workplace measurements were used to define recommendations for reducing the chemical risks in CRT screens recycling facilities and for promoting the design and development of “clean and safe” processes in emerging recycling channels.« less

Comparison of the reflectance characteristics of polytetrafluoroethylene and barium sulfate paints

NASA Technical Reports Server (NTRS)

Butner, C. L.; Schutt, J. B.; Shai, M. C.

1984-01-01

Preliminary results are presented of the directional reflectance measurements taken on two tetrafluorethylene (TFE) paints formulated with silicone binders. Both paints are found to be more Lambertian than barium sulfate paint and pressed powder, although the pigment to binder ratios for barium sulfate and TFE paints are about 133 and 3.3 to 1, respectively. The TFE paints exhibit total visible reflectances above 90 percent and offer surfaces that are not significantly affected by water.

NASA/Max Planck Institute Barium Ion Cloud Project.

NASA Technical Reports Server (NTRS)

Brence, W. A.; Carr, R. E.; Gerlach, J. C.; Neuss, H.

1973-01-01

NASA and the Max Planck Institute for Extraterrestrial Physics (MPE), Munich, Germany, conducted a cooperative experiment involving the release and study of a barium cloud at 31,500 km altitude near the equatorial plane. The release was made near local magnetic midnight on Sept. 21, 1971. The MPE-built spacecraft contained a canister of 16 kg of Ba CuO mixture, a two-axis magnetometer, and other payload instrumentation. The objectives of the experiment were to investigate the interaction of the ionized barium cloud with the ambient medium and to deduce the properties of electric fields in the proximity of the release. An overview of the project is given to briefly summarize the organization, responsibilities, objectives, instrumentation, and operational aspects of the project.

Electromagnetic properties of photodefinable barium ferrite polymer composites

NASA Astrophysics Data System (ADS)

Sholiyi, Olusegun; Lee, Jaejin; Williams, John D.

2014-07-01

This article reports the magnetic and microwave properties of a Barium ferrite powder suspended in a polymer matrix. The sizes for Barium hexaferrite powder are 3-6 μm for coarse and 0.8-1.0 μm for the fine powder. Ratios 1:1 and 3:1 (by mass) of ferrite to SU8 samples were characterized and analyzed for predicting the necessary combinations of these powders with SU8 2000 Negative photoresist. The magnetization properties of these materials were equally determined and were analyzed using Vibrating Sample Magnetometer (VSM). The Thru, Reflect, Line (TRL) calibration technique was employed in determining complex relative permittivity and permeability of the powders and composites with SU8 between 26.5 and 40 GHz.

Hydrogen-Bonding System in Barium Nitroprusside 6.5-Hydrate

NASA Astrophysics Data System (ADS)

Navaza, A.; Chevrier, G.; Guida, J. A.

1995-01-01

The hydrogen-bond system in barium nitroprusside 6.5-hydrate, [Ba 2(H 2O) 10][Fe(CN) 5NOl 23H 2O], has been determined by neutron diffraction on monocrystals. Results show the compound to be orthorhombic, space group Cmc2 1 (36), a = 16.008(43), b = 11.550(3), c = 16.648(5) Å, V = 3078(3) Å 3, Z = 4. Refinement of the structure, using 973 observed structure factors, converged to the final RW factor of 0.058. The 2 independent barium atoms, separated 4.60 Å, share a plane of three water molecules forming dimeric tetravalent units. The nitroprusside anions deviate from the C4r ideal symmetry, but this deviation is less than that observed in other nitroprussides. The 10 crystallographically independent water molecules have been classified according to their coordination. Analysis of the H-bond strength, together with a comparison of the packing of the two known barium nitroprusside hydrates (3-hydrate and 6.5-hydrate), suggests that the water molecules labeled as W(1), W(7), W(8), and W(9) could be lost during the partial dehydration of 6.5-hydrate into 3-hydrate.

The Tordo 1 polar cusp barium plasma injection experiment

NASA Technical Reports Server (NTRS)

Wescott, E. M.; Stenbaek-Nielsen, H. C.; Davis, T. N.; Jeffries, R. A.; Roach, W. H.

1978-01-01

In January 1975, two barium plasma injection experiments were carried out with rockets launched into the upper atmosphere where field lines from the dayside cusp region intersect the ionosphere. The Tordo 1 experiment took place near the beginning of a worldwide magnetic storm. It became a polar cap experiment almost immediately as convection perpendicular to the magnetic field moved the fluorescent plasma jet away from the cusp across the polar cap in an antisunward direction. Convection across the polar cap with an average velocity of more than 1 km/s was observed for nearly 40 min until the barium flux tubes encountered large electron fields associated with a poleward bulge of the auroral oval near Greenland. Prior to the encounter with the aurora near Greenland there is evidence of upward acceleration of the barium ions while they were in the polar cap. The three-dimensional observations of the plasma orientation and motion give an insight into convection from the cusp region across the polar cap, the orientation of the polar cap magnetic field lines out to several earth radii, the causes of polar cap magnetic perturbations, and parallel acceleration processes.

Modified Calix[4]crowns as Molecular Receptors for Barium.

PubMed

Steinberg, Janine; Bauer, David; Reissig, Falco; Köckerling, Martin; Pietzsch, Hans-Jürgen; Mamat, Constantin

2018-06-01

Invited for this month's cover picture is the group around Dr. Constantin Mamat at the Institute of Radiopharmaceutical Cancer Research at the Helmholtz-Zentrum Dresden-Rossendorf (Germany) together with Prof. Martin Köckerling from the University of Rostock (Germany). The cover picture shows the ability of special functionalized calix[4]crown-6 derivatives to stably bind group 2 metals like barium. This binding mode is highly important for radiopharmaceutical applications not to lose the respective radiometal in vivo to avoid high background signals and/or false positive results and damages in other tissues. For this purpose, different calix[4]crowns were tested, based upon their potential to stably bind barium as surrogate for radium. Radium nuclides are known to be good candidates for usage in α-targeted therapies. Currently, radium-223 is used for α-therapy of bone metastases because of its calcium mimetics. Our aim is to apply the radium to treat other cancer tissues. That's why we need novel chelators to stably fix groups 2 metals like barium and radium. Read the full text of their Full Paper at https://doi.org/10.1002/open.201800019.

Study of the photovoltaic effect in thin film barium titanate

NASA Technical Reports Server (NTRS)

Grannemann, W. W.; Dharmadhikari, V. S.

1981-01-01

The photoelectric effect in structures consisting of metal deposited barium titanate film silicon is described. A radio frequency sputtering technique is used to deposit ferroelectric barium titantate films on silicon and quartz. Film properties are measured and correlated with the photoelectric effect characteristics of the films. It was found that to obtain good quality pin hole free films, it is necessary to reduce the substrate temperature during the last part of the deposition. The switching ability of the device with internal applied voltage is improved when applied with a ferroelectric memory device.

ION-EXCHANGE METHOD FOR SEPARATING RADIUM FROM RADIUM-BARIUM MIXTURES

DOEpatents

Fuentevilla, M.E.

1959-06-30

An improved process is presented for separating radium from an aqueous feed solution containing radium and barium values and a complexing agent for these metals. In this process a feed solutlon containing radium and barium ions and a complexing agent for said ions ls cycled through an exchange zone in resins. The radiumenriched resin is then stripped of radium values to form a regeneration liquid, a portion of which is collected as an enriched product, the remaining portion being recycled to the exchange zone to further enrich the ion exchange resin in radium.

Comparison of endoscopy and barium swallow with marshmallow in dysphagia.

PubMed

Somers, S; Stevenson, G W; Thompson, G

1986-06-01

Forty-four patients with dysphagia were examined both by endoscopy and by barium swallow with a marshmallow bolus. In these patients 36 stenoses were found: 34 by radiology and 30 by endoscopy. The radiologic criteria for stenosis included arrest of the marshmallow in a manner to support a column of barium and reproduction of the patient's symptoms at the time this occurred. Radiologic false negative findings were partly due to an inability by patients to swallow an adequate marshmallow bolus; endoscopic failures were associated with small endoscopes and mild stenoses.

Barium Tagging from nEXO Using Resonance Ionization Spectroscopy

NASA Astrophysics Data System (ADS)

Twelker, K.; Kravitz, S.

nEXO is a 5-ton liquid enriched-xenon time projection chamber (TPC) to search for neutrinoless double-beta decay, designed to have the sensitivity to completely probe the inverted mass hierarchy of Majorana neutrinos. The detector will accommodate-as a background reduction technique-a system to recover and identify the barium decay product. This upgrade will allow a background-free measurement of neutrinoless double-beta decay and increase the half-life sensitivity of the experiment by at least one order of magnitude. Ongoing research and development includes a system to test barium extraction from liquid xenon using surface adsorption and Resonance Ionization Spectroscopy (RIS).

Phonon characteristics of high {Tc} superconductors from neutron Doppler broadening measurements

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

Trela, W.J.; Kwei, G.H.; Lynn, J.E.

Statistical information on the phonon frequency spectrum of materials can be measured by neutron transmission techniques if they contain nuclei with low energy resonances, narrow enough to be Doppler-broadened, in their neutron cross sections. The authors have carried out some measurements using this technique for materials of the lanthanum barium cuprate class, La{sub 2{minus}x}Ba{sub x}CuO{sub 4}. Two samples with slightly different concentrations of oxygen, one being superconductive, the other not, were examined. Pure lanthanum cuprate was also measured. Lanthanum, barium and copper all have relatively low energy narrow resonances. Thus it should be possible to detect differences in the phononsmore » carried by different kinds of atom in the lattice. Neutron cross section measurements have been made with high energy resolution and statistical precision on the 59m flight path of LANSCE, the pulsed spallation neutron source at Los Alamos National Laboratory. Measurements on all three materials were made over a range of temperatures from 15K to 300K, with small steps through the critical temperature region near 27K. No significant changes in the mean phonon energy of the lanthanum atoms were observed near the critical temperature of the super-conducting material. It appears however that the mean phonon energy of lanthanum in the superconductor is considerably higher than that in the non-superconductors. The samples used in this series of experiments were too thin in barium and copper to determine anything significant about their phonon spectra.« less

75 FR 20625 - Barium Chloride From China

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-20

... INTERNATIONAL TRADE COMMISSION [Investigation No. 731-TA-149 (Third Review)] Barium Chloride From China AGENCY: United States International Trade Commission. ACTION: Revised schedule for the subject review. DATES: Effective Date: April 9, 2010. FOR FURTHER INFORMATION CONTACT: Amy Sherman (202-205-3289...

Metal electrode for amorphous silicon solar cells

DOEpatents

Williams, Richard

1983-01-01

An amorphous silicon solar cell having an N-type region wherein the contact to the N-type region is composed of a material having a work function of about 3.7 electron volts or less. Suitable materials include strontium, barium and magnesium and rare earth metals such as gadolinium and yttrium.

Observation of a barium xenon exciplex within a large argon cluster.

PubMed

Briant, M; Gaveau, M-A; Mestdagh, J-M

2010-07-21

Spectroscopic measurements provide fluorescence and excitation spectra of a single barium atom codeposited with xenon atoms on argon clusters of average size approximately 2000. The spectra are studied as a function of the number of xenon atoms per cluster. The excitation spectrum with approximately 10 xenon atoms per cluster is qualitatively similar to that observed when no xenon atom is present on the cluster. It consists of two bands located on each side of the 6s6p (1)P-6s(2) (1)S resonance line of the free barium. In contrast, the fluorescence spectrum differs qualitatively since a barium-xenon exciplex is observed, which has no counterpart in xenon free clusters. In particular an emission is observed, which is redshifted by 729 cm(-1) with respect to the Ba(6s6p (1)P-6s(2) (1)S) resonance line.

Prompt ionization in the CRIT II barium releases. [Critical Ionization Tests

NASA Technical Reports Server (NTRS)

Torbert, R. B.; Kletzing, C. A.; Liou, K.; Rau, D.

1992-01-01

Observations of electron and ion distributions inside a fast neutral barium jet in the ionosphere show significant fluxes within 4 km of release, presumably related to beam plasma instability processes involved in the Critical Ionization Velocity (CIV) effect. Electron fluxes exceeding 5 x 10 exp 12/sq cm-str-sec-keV were responsible for ionizing both the streaming barium and ambient oxygen. Resulting ion fluxes seem to be consistent with 1-2 percent ionization of the fast barium, as reported by optical observations, although the extended spatial distribution of the optically observed ions is difficult to reconcile with the in situ observations. When the perpendicular velocity of the neutrals falls below critical values, these processes shut off. Although these observations resemble the earlier Porcupine experimental results (Haerendel, 1982), theoretical understanding of the differences between these data and that of earlier negative experiments is still lacking.

The value of the preoperative barium-enema examination in the assessment of pelvic masses

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

Gedgaudas, R.K.; Kelvin, F.M.; Thompson, W.M.

1983-03-01

The value of the barium-enema examination in the assessment of pelvic masses was studied in 44 patients. Findings from those barium-enema examinations and from pathological specimens from 37 patients who had malignant tumors and seven patients who had endometriosis were retrospectively analyzed to determine if the barium-enema examination is useful in differentiating extrinsic lesions with and without invasion of the colon. None of the 12 patients who had extrinsic lesions had any of the criteria that indicated bowel-wall invasion. These criteria included fixation and serrations of the bowel wall in all patients with invasion, and ulceration and fistulizaton in thosemore » patients who had complete transmural invasion. In patients with pelvic masses, the preoperative barium-enema examination may be useful to the surgeon in planning surgery and in preparing the patient for the possibility of partial colectomy or colostomy.« less

SPIO-labeled Yttrium Microspheres for MR Imaging Quantification of Transcatheter Intrahepatic Delivery in a Rodent Model

PubMed Central

Li, Weiguo; Zhang, Zhuoli; Gordon, Andrew C.; Chen, Jeane; Nicolai, Jodi; Lewandowski, Robert J.; Omary, Reed A.

2016-01-01

Purpose To investigate the qualitative and quantitative impacts of labeling yttrium microspheres with increasing amounts of superparamagnetic iron oxide (SPIO) material for magnetic resonance (MR) imaging in phantom and rodent models. Materials and Methods Animal model studies were approved by the institutional Animal Care and Use Committee. The r2* relaxivity for each of four microsphere SPIO compositions was determined from 32 phantoms constructed with agarose gel and in eight concentrations from each of the four compositions. Intrahepatic transcatheter infusion procedures were performed in rats by using each of the four compositions before MR imaging to visualize distributions within the liver. For quantitative studies, doses of 5, 10, 15, or 20 mg 2% SPIO-labeled yttrium microspheres were infused into 24 rats (six rats per group). MR imaging R2* measurements were used to quantify the dose delivered to each liver. Pearson correlation, analysis of variance, and intraclass correlation analyses were performed to compare MR imaging measurements in phantoms and animal models. Results Increased r2* relaxivity was observed with incremental increases of SPIO microsphere content. R2* measurements of the 2% SPIO–labeled yttrium microsphere concentration were well correlated with known phantom concentrations (R2 = 1.00, P < .001) over a broader linear range than observed for the other three compositions. Microspheres were heterogeneously distributed within each liver; increasing microsphere SPIO content produced marked signal voids. R2*-based measurements of 2% SPIO–labeled yttrium microsphere delivery were well correlated with infused dose (intraclass correlation coefficient, 0.98; P < .001). Conclusion MR imaging R2* measurements of yttrium microspheres labeled with 2% SPIO can quantitatively depict in vivo intrahepatic biodistribution in a rat model. © RSNA, 2015 Online supplemental material is available for this article. PMID:26313619

Biodistribution of strontium and barium in the developing and mature skeleton of rats.

PubMed

Panahifar, Arash; Chapman, L Dean; Weber, Lynn; Samadi, Nazanin; Cooper, David M L

2018-06-19

Bone acts as a reservoir for many trace elements. Understanding the extent and pattern of elemental accumulation in the skeleton is important from diagnostic, therapeutic, and toxicological perspectives. Some elements are simply adsorbed to bone surfaces by electric force and are buried under bone mineral, while others can replace calcium atoms in the hydroxyapatite structure. In this article, we investigated the extent and pattern of skeletal uptake of barium and strontium in two different age groups, growing, and skeletally mature, in healthy rats. Animals were dosed orally for 4 weeks with either strontium chloride or barium chloride or combined. The distribution of trace elements was imaged in 3D using synchrotron K-edge subtraction micro-CT at 13.5 µm resolution and 2D electron probe microanalysis (EPMA). Bulk concentration of the elements in serum and bone (tibiae) was also measured by mass spectrometry to study the extent of uptake. Toxicological evaluation did not show any cardiotoxicity or nephrotoxicity. Both elements were primarily deposited in the areas of active bone turnover such as growth plates and trabecular bone. Barium and strontium concentration in the bones of juvenile rats was 2.3 times higher, while serum levels were 1.4 and 1.5 times lower than adults. In all treatment and age groups, strontium was preferred to barium even though equal molar concentrations were dosed. This study displayed spatial co-localization of barium and strontium in bone for the first time. Barium and strontium can be used as surrogates for calcium to study the pathological changes in animal models of bone disease and to study the effects of pharmaceutical compounds on bone micro-architecture and bone remodeling in high spatial sensitivity and precision.

Effect of yttrium on martensite-austenite phase transformation temperatures and high temperature oxidation kinetics of Ti-Ni-Hf high-temperature shape memory alloys

NASA Astrophysics Data System (ADS)

Kim, Jeoung Han; Kim, Kyong Min; Yeom, Jong Taek; Young, Sung

2016-03-01

The effect of yttrium (< 5.5 at%) on the martensite-austenite phase transformation temperatures, microstructural evolution, and hot workability of Ti-Ni-Hf high-temperature shape memory alloys is investigated. For these purposes, differential scanning calorimetry, hot compression, and thermo-gravimetric tests are conducted. The phase transformation temperatures are not noticeably influenced by the addition of yttrium up to 4.5 at%. Furthermore, the hot workability is not significantly affected by the yttrium addition up to 1.0 at%. However, when the amount of yttrium addition exceeds 1.0 at%, the hot workability deteriorates significantly. In contrast, remarkable improvement in the high temperature oxidation resistance due to the yttrium addition is demonstrated. The total thickness of the oxide layers is substantially thinner in the Y-added specimen. In particular, the thickness of (Ti,Hf) oxide layer is reduced from 200 µm to 120 µm by the addition of 0.3 at% Y.

Chromospherically active stars. 11: Giant with compact hot companions and the barium star scenario

NASA Technical Reports Server (NTRS)

Fekel, Francis C.; Henry, Gregory W.; Busby, Michael R.; Eitter, Joseph J.

1993-01-01

We have determined spectroscopic orbits for three chromsopherically active giants that have hot compact companions. They are HD 160538 (KO III + wd, P = 904 days), HD 165141 (G8 III + wd, P approximately 5200 days), and HD 185510 (KO III + sdB, P = 20.6619 days). By fitting an IUE spectrum with theoretical models, we find the white dwarf companion of HD 165141 has a temperature of about 35,000 K. Spectral types and rotational velocities have been determined for the three giants and distances have been estimated. These three systems and 39 Ceti are compared with the barium star mass-transfer scenario. The long-period mild barium giant HD 165141 as well as HD 185510 and 39 Ceti, which have relatively short periods and normal abundance giants, appear to be consistent with this scenario. The last binary, HD 160538, a system with apparently near solar abundances, a white dwarf companion, and orbital characteristics similar to many barium stars, demonstrates that the existence of a white dwarf companion is insufficient to produce a barium star. The paucity of systems with confirmed white dwarf companions makes abundance analyses of HD 160538 and HD 165141 of great value in examining the role of metallicity in barium star formation.

Chromospherically active stars. 6: Giants with compact hot companions and the barium star scenario

NASA Technical Reports Server (NTRS)

Fekel, Francis C.; Henry, Gregory W.; Busby, Michael R.; Eitter, Joseph J.

1993-01-01

We have determined spectroscopic orbits for three chromospherically active giants that have hot compact companions. They are HD 160538 (K0 III + wd, P = 904 days), HD 165141 (G8 III + wd, P approximately 5200 days), and HD 185510 (K0 III + sdB, P = 20.6619 days). By fitting an IUE spectrum with theoretical models, we find the white dwarf companion of HD 165141 has a temperature of about 35000 K. Spectral types and rotational velocities have been determined for the three giants and distances have been estimated. These three systems and 39 Ceti are compared with the barium star mass-transfer scenario. The long-period mild barium giant HD 165141 as well as HD 185510 and 39 Ceti, which have relatively short periods and normal abundance giants, appear to be consistent with this scenario. The last binary, HD 160538, a system with apparently near solar abundances, a white dwarf companion, and orbital characteristics similar to many barium stars, demonstrates that the existence of a white-dwarf companion is insufficient to produce a barium star. The paucity of systems with confirmed white-dwarf companions makes abundance analyses of HD 160538 and HD 165141 of great value in examining the role of metallicity in barium star formation.

Numerical simulation of a radially injected barium cloud

NASA Technical Reports Server (NTRS)

Swift, D. W.; Wescott, E. M.

1981-01-01

Electrostatic two-dimensional numerical simulations of a radially symmetric barium injection experiment demonstrate that ions created by solar UV irradiation are electrostatically bound to the electrons which remain tied to the field lines on which they are created. Two possible instabilities are identified, but neither of them causes the barium plasma cloud to polarize in a way that would permit the plasma to keep up with the neutrals. In a second model, the velocity of the neutrals is allowed to be a function of the azimuthal angle. Here, a portion of the cloud does polarize in a way that allows a portion of the plasma to detach and move outward at the approximate speed of the neutrals. No rapid detachment is found when only the density of the neutrals is given an azimuthal asymmetry.

Barium isotopes in Allende meteorite - Evidence against an extinct superheavy element

NASA Technical Reports Server (NTRS)

Lewis, R. S.; Anders, E.; Shimamura, T.; Lugmair, G. W.

1983-01-01

Carbon and chromite fractions from the Allende meteorite that contain isotopically anomalous xenon-131 to xenon-136 (carbonaceous chondrite fission or CCF xenon) at up to 5 x 10 to the 11th atoms per gram show no detectable isotopic anomalies in barium-130 to barium-138. This rules out the possibility that the CCF xenon was formed by in situ fission of an extinct superheavy element. Apparently the CCF xenon and its carbonaceous carrier are relics from stellar nucleosynthesis.

Optimization Recovery of Yttrium Oxide in Precipitation, Extraction, and Stripping Process

NASA Astrophysics Data System (ADS)

Perwira, N. I.; Basuki, K. T.; Biyantoro, D.; Effendy, N.

2018-04-01

Yttrium oxide can be used as a dopant control rod of nuclear reactors in YSH material and superconductors. Yttrium oxide is obtained in the Xenotime mineral derived from byproduct of tin mining PT Timah Bangka which contain rare earth elements (REE) dominant Y, Dy, and Gd whose content respectively about 29.53%, 7.76%, and 2.58%. Both usage in the field of nuclear and non-nuclear science and technology is need to pure from the impurities. The presence of impurities in the yttrium oxide may affect the characteristic of the material and the efficiency of its use. Thus it needs to be separated by precipitation and extraction-stripping and calcination in the making of the oxide. However, to obtain higher levels of Yttrium oxide, it is necessary to determine the optimum conditions for its separation. The purpose of this research was to determine the optimum pH of precipitation, determine acid media and concentration optimum in extraction and stripping process and determine the efficiency of the separation of Y from REE concentrate. This research was conducted with pH variation in the precipitation process that pHs were 4 - 8, the difference of acid media for the extraction process, i.e., HNO3, HCl and H2SO4 with each concentration of 0,5 M; 1 M; 1,5 M; and 2 M and for stripping process were HNO3, HCl, and H2SO4 with each concentration of 1 M; 2M; and 3 M. Based on the result, the optimum pH of precipitation process was 6,5, the optimumacid media was HNO3 0,5 M, and for stripping process media was HNO3 3 M. The efficiency of precipitation process at pH 6,5 was 69,53 %, extraction process was 96.39% and stripping process was 4,50%. The separation process from precipitation to extraction had increased the purity and the highest efficiency recovery of Y was in the extraction process and obtained Y2O3 purer compared to the feed with the Y2O3 content of 92.87%.

75 FR 19657 - Barium Chloride From China

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-15

... China AGENCY: United States International Trade Commission. ACTION: Notice of Commission determination... China. SUMMARY: The Commission hereby gives notice that it will proceed with a full review pursuant to... antidumping duty order on barium chloride from China would be likely to lead to continuation or recurrence of...

Theory of High-T{sub c} Superconducting Cuprates Based on Experimental Evidence

DOE R&D Accomplishments Database

Abrikosov, A. A.

1999-12-10

A model of superconductivity in layered high-temperature superconducting cuprates is proposed, based on the extended saddle point singularities in the electron spectrum, weak screening of the Coulomb interaction and phonon-mediated interaction between electrons plus a small short-range repulsion of Hund's, or spin-fluctuation, origin. This permits to explain the large values of T{sub c}, features of the isotope effect on oxygen and copper, the existence of two types of the order parameter, the peak in the inelastic neutron scattering, the positive curvature of the upper critical field, as function of temperature etc.

Mott insulator-to-metal transition in yttrium-doped CaIrO₃.

PubMed

Gunasekera, J; Chen, Y; Kremenak, J W; Miceli, P F; Singh, D K

2015-02-11

We report on the study of insulator-to-metal transition in post-perovskite compound CaIrO3. It is discovered that a gradual chemical substitution of calcium by yttrium leads to the onset of strong metallic behavior in this compound. This observation is in stark contrast to BaIrO3, which preserves its Mott insulating behavior despite excess of the charge carriers due to yttrium doping. Magnetic measurements reveal that both compounds tend to exhibit magnetic character irrespective of the chemical substitution of Ca or Ba. We analyze these unusual observations in light of recent researches that suggest that CaIrO3 does not necessarily possess j = 1/2 ground state due to structural distortion. The insulator-to-metal transition in CaIrO3 will spur new researches to explore more exotic ground state, including superconductivity, in post-perovskite Mott insulators.

Fatal Liver Damage After Barium Enemas Containing Tannic Acid

PubMed Central

Lucke, Hans H.; Hodge, Kenneth E.; Patt, Norman L.

1963-01-01

Tannic acid contained in the barium enema was found to have been the sole known potential hepatotoxin in four of the five cases of fulminating fatal liver failure that occurred in a 213-bed hospital over a period of 27 months. In the other case halothane anesthesia had also been administered. Autopsies (performed on four of the cases) did not suggest viral hepatitis but showed substantially indentical hepatic changes, not unlike those reported in the past following tannic acid exposure. Proof is not claimed that tannic acid was the cause of these deaths, but further investigation regarding the safety of its administration in barium enemas is advocated. ImagesFig. 1 PMID:14079135

Effect of the pseudogap on the transition temperature in the cuprates and implications for its origin

DOE PAGES

Mishra, Vivek; Chatterjee, U.; Campuzano, J. C.; ...

2014-03-30

We present cuprates that possess a large pseudogap that spans much of their phase diagram. The origin of this pseudogap is as debated as the mechanism for high-temperature superconductivity. In one class of theories, the pseudogap arises from some instability not related to pairing, typically charge, spin or orbital current ordering. Evidence of this has come from a variety of measurements indicating symmetry breaking. On the other side are theories where the pseudogap is associated with pairing. This ranges from preformed pairs to resonating valence bond theories where spin singlets become charge coherent. Here, we study pairing in the cupratesmore » by constructing the pair vertex using spectral functions derived from angle-resolved photoemission data. Assuming that the pseudogap is not due to pairing, we find that the superconducting instability is strongly suppressed, in stark contrast to what is actually observed. We trace this suppression to the destruction of the BCS logarithmic singularity from a combination of the pseudogap and lifetime broadening. In conclusion, our findings strongly support those theories of the cuprates where the pseudogap is instead due to pairing.« less

Reflectance, Optical Properties, and Stability of Molybdenum/Strontium and Molybdenum/Yttrium Multilayer Mirrors

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

Kjornrattanawanich, Benjawan

2002-09-01

The motivation of this work is to develop high reflectance normal-incidence multilayer mirrors in the 8-12 nm wavelength region for applications in astronomy and extreme ultraviolet lithography. To achieve this goal, Mo/Sr and Mo/Y multilayers were studied. These multilayers were deposited with a UHV magnetron sputtering system and their reflectances were measured with synchrotron radiation. High normal-incidence reflectances of 23% at 8.8 nm, 40.8% at 9.4 nm, and 48.3% at 10.5 nm were achieved. However, the reflectance of Mo/Sr multilayers decreased rapidly after exposure to air. Attempts to use thin layers of carbon to passivate the surface of Mo/Sr multilayers were unsuccessful. Experimental results on the refractive indexmore » $$\\tilde{n}$$ = 1-δ + iβ of yttrium and molybdenum in the 50-1300 eV energy region are reported in this work. This is the first time ever that values on the refractive index of yttrium are measured in this energy range. The absorption part β was determined through transmittance measurements. The dispersive part δ was calculated by means of the Kramers-Kronig formalism. The newly determined values of the refractive index of molybdenum are in excellent agreement with the published data. Those of yttrium are more accurate and contain fine structures around the yttrium M-absorption edges where Mo/Y multilayers operate. These improved sets of optical data lead to better design and modeling of the optical properties of Mo/Y multilayers. The reflectance quality of Mo/Y multilayers is dependent on their optical and structural properties. To correlate these properties with the multilayer reflectance, x-ray diffraction, Rutherford backscattering spectrometry, and transmission electron microscopy were used to analyze samples. Normal-incidence reflectances of 32.6% at 9.27 nm, 38.4% at 9.48 nm, and 29.6% at 9.46 nm were obtained from three representative Mo/Y multilayers which had about 0%, 25%, and 39% atomic oxygen assimilated in their

The novel metallic states of the cuprates: Topological Fermi liquids and strange metals

NASA Astrophysics Data System (ADS)

Sachdev, Subir; Chowdhury, Debanjan

2016-12-01

We review ideas on the nature of the metallic states of the hole-doped cuprate high temperature superconductors, with an emphasis on the connections between the Luttinger theorem for the size of the Fermi surface, topological quantum field theories (TQFTs), and critical theories involving changes in the size of the Fermi surface. We begin with the derivation of the Luttinger theorem for a Fermi liquid, using momentum balance during a process of flux insertion in a lattice electronic model with toroidal boundary conditions. We then review the TQFT of the ℤ spin liquid, and demonstrate its compatibility with the toroidal momentum balance argument. This discussion leads naturally to a simple construction of "topological" Fermi liquid states: the fractionalized Fermi liquid (FL*) and the algebraic charge liquid (ACL). We present arguments for a description of the pseudogap metal of the cuprates using ℤ-FL* or ℤ-ACL states with Ising-nematic order. These pseudogap metal states are also described as Higgs phases of a SU(2) gauge theory. The Higgs field represents local antiferromagnetism, but the Higgs-condensed phase does not have long-range antiferromagnetic order: the magnitude of the Higgs field determines the pseudogap, the reconstruction of the Fermi surface, and the Ising-nematic order. Finally, we discuss the route to the large Fermi surface Fermi liquid via the critical point where the Higgs condensate and Ising nematic order vanish, and the application of Higgs criticality to the strange metal.

Barium swallow study in routine clinical practice: a prospective study in patients with chronic cough*,**

PubMed Central

Nin, Carlos Shuler; Marchiori, Edson; Irion, Klaus Loureiro; Paludo, Artur de Oliveira; Alves, Giordano Rafael Tronco; Hochhegger, Daniela Reis; Hochhegger, Bruno

2013-01-01

OBJECTIVE: To assess the routine use of barium swallow study in patients with chronic cough. METHODS: Between October of 2011 and March of 2012, 95 consecutive patients submitted to chest X-ray due to chronic cough (duration > 8 weeks) were included in the study. For study purposes, additional images were obtained immediately after the oral administration of 5 mL of a 5% barium sulfate suspension. Two radiologists systematically evaluated all of the images in order to identify any pathological changes. Fisher's exact test and the chi-square test for categorical data were used in the comparisons. RESULTS: The images taken immediately after barium swallow revealed significant pathological conditions that were potentially related to chronic cough in 12 (12.6%) of the 95 patients. These conditions, which included diaphragmatic hiatal hernia, esophageal neoplasm, achalasia, esophageal diverticulum, and abnormal esophageal dilatation, were not detected on the images taken without contrast. After appropriate treatment, the symptoms disappeared in 11 (91.6%) of the patients, whereas the treatment was ineffective in 1 (8.4%). We observed no complications related to barium swallow, such as contrast aspiration. CONCLUSIONS: Barium swallow improved the detection of significant radiographic findings related to chronic cough in 11.5% of patients. These initial findings suggest that the routine use of barium swallow can significantly increase the sensitivity of chest X-rays in the detection of chronic cough-related etiologies. PMID:24473762

Effect of variations in the redox potential of Gleysol on barium mobility and absorption in rice plants.

PubMed

Magalhães, Marcio Osvaldo Lima; Sobrinho, Nelson Moura Brasil do Amaral; Zonta, Everaldo; de Carvalho, Michel Miranda; Tolón-Becerra, Alfredo

2012-09-01

Two assays were designed to obtain information about the influence of redox potential variations on barium mobility and bioavailability in soil. One assay was undertaken in leaching columns, and the other was conducted in pots cultivated with rice (Oryza sativa) using soil samples collected from the surface of Gleysol in both assays. Three doses of barium (100,300 mg kg(-1) and 3000 mg kg(-1)-soil dry weight) and two redox potential values (oxidizing and reducing) were evaluated. During the incubation period, the redox potential (Eh) was monitored in columns and pots until values of -250 mV were reached. After the incubation period, geochemical partitioning was conducted on the barium using the European Communities Bureau of Reference (BCR) method. Rainfall of 200 mm d(-1) was simulated in the columns and in the planting of rice seedlings in the pots. The results of the geochemical partitioning demonstrated that the condition of reduction favors increased barium concentrations in the more labile chemical forms and decreased levels in the chemical forms related to oxides. The highest barium concentrations in leached extracts (3.36 mg L(-1)) were observed at the highest dose and condition of reduction at approximately five times above the drinking water standard. The high concentrations of barium in the soil did not affect plant dry matter production. The highest levels and accumulation of barium in roots, leaves, and grains of rice were found at the highest dose and condition of reduction. These results demonstrate that reduction leads to solubilization of barium sulfate, thereby favoring greater mobility and bioavailability of this element. Copyright © 2012 Elsevier Ltd. All rights reserved.

Evidence against barium in the mushroom Trogia venenata as a cause of sudden unexpected deaths in Yunnan, China.

PubMed

Zhang, Ying; Li, Yanchun; Wu, Gang; Feng, Bang; Yoell, Shanze; Yu, Zefen; Zhang, Keqin; Xu, Jianping

2012-12-01

This study examined barium concentrations in the mushroom Trogia venenata, the leading culprit for sudden unexpected deaths in Yunnan, southwest China. We found that barium concentrations in T. venenata from Yunnan were low and comparable to other foods, inconsistent with barium concentrations in this mushroom as a significant contributor to these deaths.

Age of Sulfate Methane Transition Zone Determined by Modelling Barium Sulfate Growth

NASA Astrophysics Data System (ADS)

Lin, S.; Wang, W. C.; Lien, K. L.; Liu, C. C.; Fan, L. F.

2017-12-01

Methane seep to the sediment/water interface could initiate anaerobic methane oxidation (AOM) with subsequent build up of chemosynthetic community, carbonate, pyrite and a number of other authigenic mineral formation. Determination the duration, sequence and time of methane seeps are keys to understand how methane seep to the environment and degree of alteration to the vicinity area. However, limited method existed in defining time of methane seep since there are some known problems involving typical dating methods, i.e. old carbon on C14 of fossil test or authigenic carbonate, thorium from surrounding matrix on U/Th authigenic carbonate dating. In this study, we have employed barium determination method (Dickens, 2001) to model timing of methane seep at two locations in the South China Sea. Our objective is to compare timing of the barium accumulation near the sulfate methane transition zone (SMTZ) on these two different locations and to seek if a similar mechanism driving the methane seep at two locations far apart. Dissolved barium, total sediment barium and aluminum were measured as well as pore water sulfate, and sediment pyrite concentrations. Time for the barium sulfate accumulation is calculated by: T = C/F, C= ∫ I x p x (1-Ø) Our results show that SMTZ is stabilized at each site for a duration of about 4000-5000 years. AOM process have been active at both sites at about the same time. In conjunction, pyrite also accumulated at a depth near the SMTZ as a result of methane oxidation. This result show that AOM could stay at the SMTZ for a relatively long period of time, on a scale of thousands of years.

Barium sulfate micro- and nanoparticles as bioinert reference material in particle toxicology.

PubMed

Loza, Kateryna; Föhring, Isabell; Bünger, Jürgen; Westphal, Götz A; Köller, Manfred; Epple, Matthias; Sengstock, Christina

2016-12-01

The inhalation of particles and their exposure to the bronchi and alveoli constitute a major public health risk. Chemical as well as particle-related properties are important factors for the biological response but are difficult to separate from each other. Barium sulfate is a completely inert chemical compound, therefore it is ideally suited to separate these two factors. The biological response of rat alveolar macrophages (NR8383) was analyzed after exposure to barium sulfate particles with three different diameters (40 nm, 270 nm, and 1.3 μm, respectively) for 24 h in vitro (particle concentrations from 12.5 to 200 μg mL - 1 ). The particles were colloidally stabilized as well as fluorescently-labeled by carboxymethylcellulose, conjugated with 6-aminofluorescein. All kinds of barium sulfate particles were efficiently taken up by NR8383 cells and found inside endo-lysosomes, but never in the cell nucleus. Neither an inflammatory nor a cytotoxic response was detected by the ability of dHL-60 and NR8383 cells to migrate towards a chemotactic gradient (conditioned media of NR8383 cells) and by the release of inflammatory mediators (CCL2, TNF-α, IL-6). The particles neither caused apoptosis (up to 200 μg mL - 1 ) nor necrosis (up to 100 μg mL - 1 ). As only adverse reaction, necrosis was found at a concentration of 200 μg mL - 1 of the largest barium sulfate particles (1.3 μm). Barium sulfate particles are ideally suited as bioinert control to study size-dependent effects such as uptake mechanisms of intracellular distributions of pure particles, especially in nanotoxicology.

Barium borate nanorod decorated reduced graphene oxide for optical power limiting applications

NASA Astrophysics Data System (ADS)

Muruganandi, G.; Saravanan, M.; Vinitha, G.; Jessie Raj, M. B.; Sabari Girisun, T. C.

2018-01-01

By simple hydrothermal method, nanorods of barium boate were successfully loaded on reduced graphene oxide sheets. Powder XRD confirms the incorporation of barium borate (2θ = 29°, (202)) along with the transition of graphene oxide (2θ = 12°, (001)) into reduced graphene oxide (2θ = 25°, (002)). In the FTIR spectra, presence of characteristic absorption peaks of rGO (1572 and 2928 cm-1) and barium borate (510, 760 and 856 cm-1) further evidences the formation of BBO:rGO nanocomposite. FESEM images potray the existence of graphene sheets as thin layers and growth of barium borate as nanorods on the sheets of reduced graphene oxide. Ground state absorption studies reveal the hypsochromic shift in the absorption maxima of the graphene layers due to reduction of graphene oxide and hypochromic shift in the absorbance intensity due to the inclusion of highly transparent barium bortae. The photoluminescence of BBO:rGO shows maximum emission in the UV region arising from the direct transitions involving the valence band and conduction band in the band gap region. Z-scan technique using CW diode pumped Nd:YAG laser (532 nm, 50 mW) exposes that both nanocomposite and individual counterpart possess saturable absorption and self-defocusing behavior. Third-order nonlinear optical coefficients of BBO:rGO nanocomposite is found to be higher than bare graphene oxide. In particular the nonlinear refractive index of nanocomposite is almost four times higher than GO which resulted in superior optical power limiting action. Strong nonlinear refraction (self-defocusing) and lower onset limiting thershold makes the BBO:rGO nanocomposite preferable candidate for laser safety devices.

Individual-specific transgenerational marking of fish populations based on a barium dual-isotope procedure.

PubMed

Huelga-Suarez, Gonzalo; Moldovan, Mariella; Garcia-Valiente, America; Garcia-Vazquez, Eva; Alonso, J Ignacio Garcia

2012-01-03

The present study focuses on the development and evaluation of an individual-specific transgenerational marking procedure using two enriched barium isotopes, (135)Ba and (137)Ba, mixed at a given and selectable molar ratio. The method is based on the deconvolution of the isotope patterns found in the sample into four molar contribution factors: natural xenon (Xe nat), natural barium (Ba nat), Ba135, and Ba137. The ratio of molar contributions between Ba137 and Ba135 is constant and independent of the contribution of natural barium in the sample. This procedure was tested in brown trout ( Salmo trutta ) kept in captivity. Trout were injected with three different Ba137/Ba135 isotopic signatures ca. 7 months and 7 days before spawning to compare the efficiency of the marking procedure at long and short term, respectively. The barium isotopic profiles were measured in the offspring by means of inductively coupled plasma mass spectrometry. Each of the three different isotopic signatures was unequivocally identified in the offspring in both whole eggs and larvae. For 9 month old offspring, the characteristic barium isotope signatures could also be detected in the otoliths even in the presence of a high and variable amount of barium of natural isotope abundance. In conclusion, it can be stated that the proposed dual-isotope marking is inheritable and can be detected after both long-term and short-term marking. Furthermore, the dual-isotope marking can be made individual-specific, so that it allows identification of offspring from a single individual or a group of individuals within a given fish group. © 2011 American Chemical Society

Theoretical Modeling of Various Spectroscopies for Cuprates and Topological Insulators

NASA Astrophysics Data System (ADS)

Basak, Susmita

Spectroscopies resolved highly in momentum, energy and/or spatial dimensions are playing an important role in unraveling key properties of wide classes of novel materials. However, spectroscopies do not usually provide a direct map of the underlying electronic spectrum, but act as a complex 'filter' to produce a 'mapping' of the underlying energy levels, Fermi surfaces (FSs) and excitation spectra. The connection between the electronic spectrum and the measured spectra is described as a generalized 'matrix element effect'. The nature of the matrix element involved differs greatly between different spectroscopies. For example, in angle-resolved photoemission (ARPES) an incoming photon knocks out an electron from the sample and the energy and momentum of the photoemitted electron is measured. This is quite different from what happens in K-edge resonant inelastic X-ray scattering (RIXS), where an X-ray photon is scattered after inducing electronic transitions near the Fermi energy through an indirect second order process, or in Compton scattering where the incident X-ray photon is scattered inelastically from an electron transferring energy and momentum to the scattering electron. For any given spectroscopy, the matrix element is, in general, a complex function of the phase space of the experiment, e.g. energy/polarization of the incoming photon and the energy/momentum/spin of the photoemitted electron in the case of ARPES. The matrix element can enhance or suppress signals from specific states, or merge signals of groups of states, making a good understanding of the matrix element effects important for not only a robust interpretation of the spectra, but also for ascertaining optimal regions of the experimental phase space for zooming in on states of the greatest interest. In this thesis I discuss a comprehensive scheme for modeling various highly resolved spectroscopies of the cuprates and topological insulators (TIs) where effects of matrix element, crystal

Optical bistability in erbium-doped yttrium aluminum garnet crystal combined with a laser diode.

PubMed

Maeda, Y

1994-01-10

Optical bistability was observed in a simple structure of an injection laser diode combined with an erbium-doped yttrium aluminum garnet crystal. Since a hysteresis characteristic exists in the relationship between the wavelength and the injection current of a laser diode, an optical memory function capable of holding the output status is confirmed. In addition, an optical signal inversion was caused by the decrease of transmission of the erbium-doped yttrium aluminum garnet crystal against the red shift (principally mode hopping) of the laser diode. It is suggested that the switching time of this phenomenon is the time necessary for a mode hopping by current injection.

Synthesis and Characterization of Iron Doped Nano Barium Titanate Through Mechanochemical Route

NASA Astrophysics Data System (ADS)

Mukherjee, Soumya; Ghosh, S.; Ghosh, C.; Mitra, M. K.

2013-04-01

Mechanochemical activation was used to prepare Fe doped barium titanate with intense milling in high energy planetary ball mill. Calcination was done at 1250°C for 30 min to obtain BaO, followed by milling with titania, at 400 rpm for 3 and 6 h. Ferric oxide was used for Fe doping. Annealing was done on the milled sample at 650, 750 and 850 °C for 3 and 6 h to generate stoichiometric compound of barium titanate phase. Fe doped barium titanate results in dense cluster of irregular polygonal shape morphology while morphology was spherical in nature for undoped sample. UV-VIS spectra analysis was carried out to determine bandgap (3.93 eV for undoped BT and 3.88 eV for Fe doped BT) followed by emission-excitation of the sample by fluorometric analysis.

Evidence against Barium in the Mushroom Trogia venenata as a Cause of Sudden Unexpected Deaths in Yunnan, China

PubMed Central

Zhang, Ying; Li, Yanchun; Wu, Gang; Feng, Bang; Yoell, Shanze; Yu, Zefen; Zhang, Keqin

2012-01-01

This study examined barium concentrations in the mushroom Trogia venenata, the leading culprit for sudden unexpected deaths in Yunnan, southwest China. We found that barium concentrations in T. venenata from Yunnan were low and comparable to other foods, inconsistent with barium concentrations in this mushroom as a significant contributor to these deaths. PMID:23042168

Plasmons in cuprate superconductors

NASA Astrophysics Data System (ADS)

Bozovic, Ivan

1990-08-01

The customary way of determining the complex dielectric constant from the measured reflectance spectra suffers from large uncertainties because of the extrapolations required for the Kramers-Kronig transformation. To avoid these, a method is introduced in which reflectance and ellipsometric data on single crystals and epitaxial films are combined. Utilizing this approach, the spectral functions of YBa2Cu3O7 (Y-Ba-Cu-O) and Bi2Sr2CaCu2O8 (Bi-Sr-Ca-Cu-O) are determined with substantially improved accuracy. This enables the unambiguous identification of optic plasmons at 1.4 eV in Y-Ba-Cu-O and at 1.1 eV in Bi-Sr-Ca-Cu-O. No other low-lying optic plasmons are detected, which likely rules out most plasmon-mediated superconductivity models. Next, the bare plasma frequency is found to be ħωp=3.2+/-0.3 eV in Y-Ba-Cu-O and ħωp=2.4+/-0.3 eV in Bi-Sr-Ca-Cu-O. These values support ascribing the strong infrared absorption to charge carriers which, however, are not free-electron-like, but rather show characteristic polaronic behavior. Finally, in both Y-Ba-Cu-O and Bi-Sr-Ca-Cu-O, it is found that Im(-1/ɛ)=βω2 for small ω, and this law is conjectured to be universal for all layered cuprate superconductors. It is again not Drude-like; it may be compatible with the layered electron-gas model. The latter implies existence of a broad band of acoustic plasmon branches.

Barium promotes anchorage-independent growth and invasion of human HaCaT keratinocytes via activation of c-SRC kinase.

PubMed

Thang, Nguyen Dinh; Yajima, Ichiro; Kumasaka, Mayuko Y; Ohnuma, Shoko; Yanagishita, Takeshi; Hayashi, Rumiko; Shekhar, Hossain U; Watanabe, Daisuke; Kato, Masashi

2011-01-01

Explosive increases in skin cancers have been reported in more than 36 million patients with arsenicosis caused by drinking arsenic-polluted well water. This study and previous studies showed high levels of barium as well as arsenic in the well water. However, there have been no reports showing a correlation between barium and cancer. In this study, we examined whether barium (BaCl(2)) may independently have cancer-related effects on human precancerous keratinocytes (HaCaT). Barium (5-50 µM) biologically promoted anchorage-independent growth and invasion of HaCaT cells in vitro. Barium (5 µM) biochemically enhanced activities of c-SRC, FAK, ERK and MT1-MMP molecules, which regulate anchorage-independent growth and/or invasion. A SRC kinase specific inhibitor, protein phosphatase 2 (PP2), blocked barium-mediated promotion of anchorage-independent growth and invasion with decreased c-SRC kinase activity. Barium (2.5-5 µM) also promoted anchorage-independent growth and invasion of fibroblasts (NIH3T3) and immortalized nontumorigenic melanocytes (melan-a), but not transformed cutaneous squamous cell carcinoma (HSC5 and A431) and malignant melanoma (Mel-ret) cells, with activation of c-SRC kinase. Taken together, our biological and biochemical findings newly suggest that the levels of barium shown in drinking well water independently has the cancer-promoting effects on precancerous keratinocytes, fibroblast and melanocytes in vitro.

75 FR 33824 - Barium Chloride From China

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-15

... China Determination On the basis of the record\\1\\ developed in the subject five-year review, the United... China would be likely to lead to continuation or recurrence of material injury to an industry in the... contained in USITC Publication 4157 (June 2010), entitled Barium Chloride from China: Investigation No. 731...

Intra-articular radioactive yttrium and triamcinolone hexacetonide: an inconclusive trial. Arthritis and Rheumatism Council Multicentre Radiosynoviorthesis Trial Group.

PubMed

1984-08-01

A restricted sequential design multicentre controlled trial of yttrium-90 against triamcinolone intra-articularly was undertaken in patients with rheumatoid arthritis with knee involvement. The trial had to be discontinued because of dwindling recruitment over time. The reasons for this and other features contributing to an inconclusive outcome are noted. This experience lends little encouragement to the idea that yttrium-90 therapy is more or less advantageous than triamcinolone hexacetonide.

Observations and theory of the AMPTE magnetotail barium releases

NASA Technical Reports Server (NTRS)

Bernhardt, P. A.; Roussel-Dupre, R. A.; Pongratz, M. B.; Haerendel, G.; Valenzuela, A.

1987-01-01

The barium releases in the magnetotail during the Active Magnetospheric Particle Tracer Explorers (AMPTE) operation were monitored by ground-based imagers and by instruments on the Ion Release Module. After each release, the data show the formation of a structured diamagnetic cavity. The cavity grows until the dynamic pressure of the expanding ions balances the magnetic pressure on its surface. The magnetic field inside the cavity is zero. The barium ions collect on the surface of the cavity, producing a shell. Plasma irregularities form along magnetic field lines draped over the surface of the cavity. The scale size of the irregularities is nearly equal to the thickness of the shell. The evolution and structuring of the diamagnetic cavity are modeled using magnetohydrodynamics theory.

Photorefractive Effect in Barium Titanate Crystals

DTIC Science & Technology

1988-08-15

photorefractivity. The titanium dioxide feed material was prepared by the hydrolysis of titanium isopropoxide , Ti(ioc3H7 )4 , according to the reaction...reduced pressure fractional distillation. This purification technique was based on the observation that titanium isopropoxide has a much lower boiling...Starting materials A major effort in this research was devoted to the synthesis of high-purity starting materials, since titanium dioxide and barium

Barium Promotes Anchorage-Independent Growth and Invasion of Human HaCaT Keratinocytes via Activation of c-SRC Kinase

PubMed Central

Thang, Nguyen Dinh; Yajima, Ichiro; Kumasaka, Mayuko Y.; Ohnuma, Shoko; Yanagishita, Takeshi; Hayashi, Rumiko; Shekhar, Hossain U.; Watanabe, Daisuke; Kato, Masashi

2011-01-01

Explosive increases in skin cancers have been reported in more than 36 million patients with arsenicosis caused by drinking arsenic-polluted well water. This study and previous studies showed high levels of barium as well as arsenic in the well water. However, there have been no reports showing a correlation between barium and cancer. In this study, we examined whether barium (BaCl2) may independently have cancer-related effects on human precancerous keratinocytes (HaCaT). Barium (5–50 µM) biologically promoted anchorage-independent growth and invasion of HaCaT cells in vitro. Barium (5 µM) biochemically enhanced activities of c-SRC, FAK, ERK and MT1-MMP molecules, which regulate anchorage-independent growth and/or invasion. A SRC kinase specific inhibitor, protein phosphatase 2 (PP2), blocked barium-mediated promotion of anchorage-independent growth and invasion with decreased c-SRC kinase activity. Barium (2.5–5 µM) also promoted anchorage-independent growth and invasion of fibroblasts (NIH3T3) and immortalized nontumorigenic melanocytes (melan-a), but not transformed cutaneous squamous cell carcinoma (HSC5 and A431) and malignant melanoma (Mel-ret) cells, with activation of c-SRC kinase. Taken together, our biological and biochemical findings newly suggest that the levels of barium shown in drinking well water independently has the cancer-promoting effects on precancerous keratinocytes, fibroblast and melanocytes in vitro. PMID:22022425

Growth and optical property characterization of textured barium titanate thin films for photonic applications

NASA Astrophysics Data System (ADS)

Dicken, Matthew J.; Diest, Kenneth; Park, Young-Bae; Atwater, Harry A.

2007-03-01

We have investigated the growth of barium titanate thin films on bulk crystalline and amorphous substrates utilizing biaxially oriented template layers. Ion beam-assisted deposition was used to grow thin, biaxially textured, magnesium oxide template layers on amorphous and silicon substrates. Growth of highly oriented barium titanate films on these template layers was achieved by molecular beam epitaxy using a layer-by-layer growth process. Barium titanate thin films were grown in molecular oxygen and in the presence of oxygen radicals produced by a 300 W radio frequency plasma. We used X-ray and in situ reflection high-energy electron diffraction (RHEED) to analyze the structural properties and show the predominantly c-oriented grains in the films. Variable angle spectroscopic ellipsometry was used to analyze and compare the optical properties of the thin films grown with and without oxygen plasma. We have shown that optical quality barium titanate thin films, which show bulk crystal-like properties, can be grown on any substrate through the use of biaxially oriented magnesium oxide template layers.

SALT reveals the barium central star of the planetary nebula Hen 2-39

NASA Astrophysics Data System (ADS)

Miszalski, B.; Boffin, H. M. J.; Jones, D.; Karakas, A. I.; Köppen, J.; Tyndall, A. A.; Mohamed, S. S.; Rodríguez-Gil, P.; Santander-García, M.

2013-12-01

Classical barium stars are binary systems which consist of a late-type giant enriched in carbon and slow neutron capture (s-process) elements and an evolved white dwarf (WD) that is invisible at optical wavelengths. The youngest observed barium stars are surrounded by planetary nebulae (PNe), ejected soon after the wind accretion of polluted material when the WD was in its preceding asymptotic giant branch (AGB) phase. Such systems are rare but powerful laboratories for studying AGB nucleosynthesis as we can measure the chemical abundances of both the polluted star and the nebula ejected by the polluter. Here, we present evidence for a barium star in the PN Hen 2-39 (PN G283.8-04.2) as one of only a few known systems. The polluted giant is very similar to that found in WeBo 1 (PN G135.6+01.0). It is a cool (Teff = 4250 ± 150 K) giant enhanced in carbon ([C/H] = 0.42 ± 0.02 dex) and barium ([Ba/Fe] = 1.50 ± 0.25 dex). A spectral type of C-R3 C24 nominally places Hen 2-39 amongst the peculiar early R-type carbon stars; however, the barium enhancement and likely binary status mean that it is more likely to be a barium star with similar properties, rather than a true member of this class. An AGB star model of initial mass 1.8 M⊙ and a relatively large carbon pocket size can reproduce the observed abundances well, provided mass is transferred in a highly conservative way from the AGB star to the polluted star (e.g. wind Roche lobe overflow). It also shows signs of chromospheric activity and photometric variability with a possible rotation period of ˜5.5 d likely induced by wind accretion. The nebula exhibits an apparent ring morphology in keeping with the other PNe around barium stars (WeBo 1 and A 70) and shows a high degree of ionization implying the presence of an invisible hot pre-WD companion that will require confirmation with UV observations. In contrast to A 70, the nebular chemical abundance pattern is consistent with non-Type I PNe, in keeping with the

Comprehensive Study of the Model Mercury-Based Cuprate Superconductors

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

Greven, Martin

This is the Final Report on DE-SC0006858, which opened 15 August 2011 and closed 14 August 2017. The Principal Investigator is Martin Greven, School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 555455 (email: greven@umn.edu). The Administrative Point of Contact is Patricia Jondahl, phone: 612-624-5599, email: awards@umn.edu. The DOE Program is the Office of Basic Energy Sciences, Program manager is Dr. P. Thiyagarajan, Neutron Scattering SC-22.2/ Germantown Bldg. (email: Thiyagarajan@science.doe.gov). The chief activity was the crystal growth, characterization, neutron and X-ray scattering study of the mercury-based cuprates, arguably the most desirable high-Tc superconductors for experimental study due to theirmore » record values of Tc and their relatively simple crystal structures. It is thought that the unusual magnetic and charge degrees of freedom of the copper-oxygen sheets that form the fundamental building block of all cuprate superconductors give rise to the high Tc and to many other unusual properties exhibited by the class of quantum materials. Neutron scattering experiments were performed to reveal the nature of the magnetic degrees of freedom of the copper-oxygen sheets, whereas X-ray scattering experiments and complementary charge-transport experiments were performed to reveal the nature of the charge degrees of freedom. In addition, collaborations were initiated with experts in the use of complementary experimental techniques. The primary products are (i) scientific articles published in peer-reviewed scientific journals, (ii) scientific presentations at national and international conferences, and (iii) education of postdoctoral researchers, PhD graduate students and undergraduate researchers by providing a research experience in crystal growth, characterization and scattering. Twenty scientific papers were published in peer-reviewed journals, thirty-one invited talks were presented at national or international conferences

Quenched disorder and vestigial nematicity in the pseudogap regime of the cuprates

PubMed Central

Nie, Laimei; Tarjus, Gilles; Kivelson, Steven Allan

2014-01-01

The cuprate high-temperature superconductors have been the focus of unprecedentedly intense and sustained study not only because of their high superconducting transition temperatures, but also because they represent the most exquisitely investigated examples of highly correlated electronic materials. In particular, the pseudogap regime of the phase diagram exhibits a variety of mysterious emergent behaviors. In the last few years, evidence from NMR and scanning tunneling microscopy (STM) studies, as well as from a new generation of X-ray scattering experiments, has accumulated, indicating that a general tendency to short-range–correlated incommensurate charge density wave (CDW) order is “intertwined” with the superconductivity in this regime. Additionally, transport, STM, neutron-scattering, and optical experiments have produced evidence—not yet entirely understood—of the existence of an associated pattern of long-range–ordered point-group symmetry breaking with an electron-nematic character. We have carried out a theoretical analysis of the Landau–Ginzburg–Wilson effective field theory of a classical incommensurate CDW in the presence of weak quenched disorder. Although the possibilities of a sharp phase transition and long-range CDW order are precluded in such systems, we show that any discrete symmetry-breaking aspect of the charge order—nematicity in the case of the unidirectional (stripe) CDW we consider explicitly—generically survives up to a nonzero critical disorder strength. Such “vestigial order,” which is subject to unambiguous macroscopic detection, can serve as an avatar of what would be CDW order in the ideal, zero disorder limit. Various recent experiments in the pseudogap regime of the hole-doped cuprates are readily interpreted in light of these results. PMID:24799709

Rare earth-doped barium gallo-germanate glasses and their near-infrared luminescence properties.

PubMed

Pisarska, Joanna; Sołtys, Marta; Górny, Agata; Kochanowicz, Marcin; Zmojda, Jacek; Dorosz, Jan; Dorosz, Dominik; Sitarz, Maciej; Pisarski, Wojciech A

2018-08-05

Near-infrared luminescence properties of Nd 3+ and Ho 3+ ions in barium gallo-germanate glasses have been reported. Several spectroscopic parameters for Nd 3+ and Ho 3+ ions have been determined from the Judd-Ofelt analysis and absorption/luminescence measurements. Quite large luminescence lifetime, quantum efficiency and stimulated emission cross-section have been obtained for the main 4 F 3/2  →  4 I 11/2 (Nd 3+ ) and 5 I 7  →  5 I 8 (Ho 3+ ) laser transitions of rare earths in barium gallo-germanate glasses. It suggests that barium gallo-germanate glass is promising for near-infrared laser application at emission wavelengths 1064 nm (Nd 3+ ) and 2020 nm (Ho 3+ ). Copyright © 2018 Elsevier B.V. All rights reserved.

Nonequilibrium phase transitions in cuprates observed by ultrafast electron crystallography.

PubMed

Gedik, Nuh; Yang, Ding-Shyue; Logvenov, Gennady; Bozovic, Ivan; Zewail, Ahmed H

2007-04-20

Nonequilibrium phase transitions, which are defined by the formation of macroscopic transient domains, are optically dark and cannot be observed through conventional temperature- or pressure-change studies. We have directly determined the structural dynamics of such a nonequilibrium phase transition in a cuprate superconductor. Ultrafast electron crystallography with the use of a tilted optical geometry technique afforded the necessary atomic-scale spatial and temporal resolutions. The observed transient behavior displays a notable "structural isosbestic" point and a threshold effect for the dependence of c-axis expansion (Deltac) on fluence (F), with Deltac/F = 0.02 angstrom/(millijoule per square centimeter). This threshold for photon doping occurs at approximately 0.12 photons per copper site, which is unexpectedly close to the density (per site) of chemically doped carriers needed to induce superconductivity.

Kinetic characteristics of the luminescence decay for industrial yttrium-gadolinium-aluminium garnet based phosphors

NASA Astrophysics Data System (ADS)

Lisitsyn, V. M.; Stepanov, S. A.; Valiev, D. T.; Vishnyakova, E. A.; Abdullin, H. A.; Marhabaeva, A. A.; Tulegenova, A. T.

2016-02-01

The spectral and decay kinetic characteristics of pulse cathodoluminescence and photoluminescence of phosphors based on yttrium-gadolinium-aluminum garnet were investigated using pulsed optical time resolved spectroscopy.

Intra-articular radioactive yttrium and triamcinolone hexacetonide: an inconclusive trial. Arthritis and Rheumatism Council Multicentre Radiosynoviorthesis Trial Group.

PubMed Central

1984-01-01

A restricted sequential design multicentre controlled trial of yttrium-90 against triamcinolone intra-articularly was undertaken in patients with rheumatoid arthritis with knee involvement. The trial had to be discontinued because of dwindling recruitment over time. The reasons for this and other features contributing to an inconclusive outcome are noted. This experience lends little encouragement to the idea that yttrium-90 therapy is more or less advantageous than triamcinolone hexacetonide. PMID:6383234

Barium-induced skeletal muscle paralysis in the rat, and its relationship to human familial periodic paralysis

PubMed Central

Schott, G. D.; McArdle, B.

1974-01-01

An in vivo study of skeletal muscle paralysis induced by intravenous barium chloride has been made in curarized and non-curarized rats. The influence of potassium and calcium chlorides, propranolol, ouabain, and prior adrenalectomy on the paralysis has also been studied. Paralysis is found to be due to a direct effect on skeletal muscle, and to correlate well with the development of hypokalaemia. Possible mechanisms of action of barium are discussed, and attention is drawn to the similarity between barium poisoning and hypokalaemic familial periodic paralysis. PMID:4813426

Crystal structures of bis-[(9S,13S,14S)-3-meth-oxy-17-methyl-morphinanium] tetra-chlorido-cobaltate and tetra-chlorido-cuprate.

PubMed

Gauchat, Eric; Nazarenko, Alexander Y

2017-01-01

(9 S ,13 S ,14 S )-3-Meth-oxy-17-methyl-morphinan (dextromethorphan) forms two isostructural salts with ( a ) tetra-chlorido-cobaltate, namely bis-[(9 S ,13 S ,14 S )-3-meth-oxy-17-methyl-morphinanium] tetra-chlorido-cobaltate, (C 18 H 26 NO) 2 [CoCl 4 ], and ( b ) tetra-chlorido-cuprate, namely bis-[(9 S ,13 S ,14 S )-3-meth-oxy-17-methyl-morphinanium] tetra-chlorido-cuprate, (C 18 H 26 NO) 2 [CuCl 4 ]. The distorted tetra-hedral anions are located on twofold rotational axes. The dextromethorphan cation can be described as being composed of two ring systems, a tetra-hydro-naphthalene system A + B and a deca-hydro-isoquinolinium subunit C + D , that are nearly perpendicular to one another: the angle between mean planes of the A + B and C + D moieties is 78.8 (1)° for ( a ) and 79.0 (1)° for ( b ). Two symmetry-related cations of protonated dextromethorphan are connected to the tetra-chlorido-cobaltate (or tetra-chlorido-cuprate) anions via strong N-H⋯Cl hydrogen bonds, forming neutral ion associates. These associates are packed in the (001) plane with no strong attractive bonding between them. Both compounds are attractive crystalline forms for unambiguous identification of the dextromethorphan and, presumably, of its optical isomer, levomethorphan.

Cobalt and Yttrium Modified TiO2 Nanotubes Based Dye-Sensitized Solar Cells for Solar-Energy Conversion

NASA Astrophysics Data System (ADS)

Shabanov, N. S.; Isaev, A. B.; Orudzhev, F. F.; Murliev, E. K.

2018-01-01

The solar-energy conversion in eosin-sensitized solar cells based on cobalt and yttrium modified TiO2 nanotubes has been studied.It is established that the doping with metal ions shifts the absorption edge for Co and Y doped titanium dioxide samples to longer and shorter wavelengths, respectively. The efficiency of solar energy conversion depends on the wide bandgap of the semiconductor anode and reaches a maximum (4.4%) for yttrium-doped TiO2 in comparison to that (4.1%) for pure titanium dioxide.

DETECTION OF SMALL LESIONS OF THE LARGE BOWEL—Barium Enema Versus Double Contrast

PubMed Central

Robinson, J. Maurice

1954-01-01

Roentgen study with the so-called opaque barium enema with some modifications is superior to double contrast study as the primary means of demonstrating polyps in the colon as well as other lesions. The method described combines fluoroscopy, high kilovoltage radiography, fluoroscopically aimed “spot films” taken with compression, suction and evacuation studies. In this way unsuspected as well as suspected polyps can be demonstrated, particularly if attention is directed to the region where polyps are most likely to be found—namely, the distal third of the large bowel. Double contrast study is quite valuable as a supplement to the modified “single contrast” barium enema, but it has not been sufficiently perfected to replace the modified opaque barium enema as a primary procedure. In many instances a combination of methods will, of course, be required. PMID:13209360

SAD phasing with in-house cu Ka radiation using barium as anomalous scatterer.

PubMed

Dhanasekaran, V; Velmurugan, D

2011-12-01

Phasing of lysozyme crystals using co-crystallized barium ions was performed using single-wavelength anomalous diffraction (SAD) method using Cu Ka radiation with in-house source of data collection. As the ion binding sites vary with respect to the pH of the buffer during crystallization, the highly isomorphic forms of lysozyme crystals grown at acidic and alkaline pH were used for the study. Intrinsic sulphur anomalous signal was also utilized with anomalous signal from lower occupancy ions for phasing. The study showed that to solve the structure by SAD technique, 2.8-fold data redundancy was sufficient when barium was used as an anomalous marker in the in-house copper X-ray radiation source for data collection. Therefore, co-crystallization of proteins with barium containing salt can be a powerful tool for structure determination using lab source.

The review of various synthesis methods of barium titanate with the enhanced dielectric properties

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

More, S. P., E-mail: smitalomte@gmail.com; Topare, R. J., E-mail: r-topare@yahoo.com

2016-05-06

The Barium Titanate is a very well known dielectric ceramic belongs to perovskite structure. It has very wide applications in the field of electronic, electro ceramic, electromechanical and electro-optical applications. Barium Titanate has very high dielectric constant as well as low dielectric loss. Substituted dielectrics are one of the most important technological compounds in modern electro ceramics. Its electrical properties can be tuned flexibly by a simple substitution technique. This has encouraged researchers to select a typical cation to be substituted at cationic sites. In the present paper, the review of various synthesis methods of Barium Titanate compound with themore » effect of different dopants, the grain size on the dielectric properties at various temperatures is discussed.« less

The negative ions of strontium and barium

NASA Astrophysics Data System (ADS)

Garwan, M. A.; Kilius, L. R.; Litherland, A. E.; Nadeau, M.-J.; Zhao, X.-L.

1990-12-01

Recent theoretical calculations have predicted a tendency toward higher electron affinities for heavier alkaline elements. Experimental evidence has been obtained for the existence of strontium and barium negative ions created from pure elements in a caesium sputter ion source. Accelerator mass spectrometric techniques were employed to resolve the above elemental negative ions from the interfering molecular species.

Meteorological support to the West German-United States Barium Ion Cloud Project.

NASA Technical Reports Server (NTRS)

Westfall, R. R.; Chamberlain, L. W.

1972-01-01

The objective of the Barium Ion Cloud Project was to study a barium ionized cloud released at an altitude of 5 earth radii. Accurate forecasting of weather conditions to prevail during the experiment period was critical to the project success. Good seeing conditions were required at all optical sites during the experiment. All meteorological support was the responsibility of the National Weather Service at Wallops Station, Virginia. Preliminary results confirm the scientists' theories of the magnetic fields and the existence of electric fields in the magnetosphere.

Polythermal investigation of viscosity of solution of metal carboxylates in VIK-grade mixed carboxylic acids: Yttrium and gadolinium carboxylates

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

Mezhov, E.A.; Samatov, A.V.; Troyanovskii, L.V.

Kinematic viscosities have been measured for solutions of yttrium and gadolinium carboxylates in grade VIK mixed carboxylic acids (MCA). It has been established that the optimal fluidity of these metal carboxylate solutions for application to articles is reached at 333 K. A regression model has been developed to describe the concentration and temperature dependences of the viscosity of yttrium- and gadolinium-containing MCA solutions. 2 refs., 3 tabs.

Inequivalence of single-particle and population lifetimes in a cuprate superconductor

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

Yang, Shuolong; Sobota, J. A.; Leuenberger, D.

2015-06-15

We study optimally doped Bi-2212 (T c=96 K) using femtosecond time- and angle-resolved photoelectron spectroscopy. Energy-resolved population lifetimes are extracted and compared with single-particle lifetimes measured by equilibrium photoemission. The population lifetimes deviate from the single-particle lifetimes in the low excitation limit by 1–2 orders of magnitude. Fundamental considerations of electron scattering unveil that these two lifetimes are in general distinct, yet for systems with only electron-phonon scattering they should converge in the low-temperature, low-fluence limit. As a result, the qualitative disparity in our data, even in this limit, suggests that scattering channels beyond electron-phonon interactions play a significant rolemore » in the electron dynamics of cuprate superconductors.« less

Structural and optical study of tellurite-barium glasses

NASA Astrophysics Data System (ADS)

Grelowska, I.; Reben, M.; Burtan, B.; Sitarz, M.; Cisowski, J.; Yousef, El Sayed; Knapik, A.; Dudek, M.

2016-12-01

The goal of this work was to determine the effect of barium oxide on the structural, thermal and optical properties of the TeO2-BaO-Na2O (TBN) and TeO2-BaO-WO3 (TBW) glass systems. Raman spectra allow relating the glass structure and vibration properties (i.e. vibrational frequencies and Raman intensities) with the glass composition. Raman spectra show the presence of TeO4 and TeO3+1/TeO3 units that conform with the glass matrix. Differential thermal analysis DTA, XRD measurements have been considered in term of BaO addition. The spectral dependence of ellipsometric angles of the tellurite-barium glass has been studied. The optical measurements were conducted on Woollam M2000 spectroscopic ellipsometer in spectral range of 190-1700 nm. The reflectance and transmittance measurements have been done on spectrophotometer Perkin Elmer, Lambda 900 in the range of 200-2500 nm (UV-VIS-NIR). From the transmittance spectrum, the energy gap was determined.

Is there a path from cuprates towards room-temperature superconductivity?

DOE PAGES

Božović, I.; Wu, J.; He, X.; ...

2017-09-01

A brief account is presented of an extensive experiment performed at Brookhaven National Laboratory, aimed at understanding the nature of high-temperature superconductivity in cuprates. Over the course of the last 12 years, over 2000 films of the prototypical high- T c superconductor, La 2-xSr xCuO 4, have been synthesized using atomic-layer-by-layer molecular beam epitaxy (ALL-MBE), characterized by a range of techniques, and patterned into devices. These were then used to measure accurately the key physical parameters in both the superconducting and the normal states, and establish their precise dependence on doping, temperature, and external fields. Our results bring in somemore » great surprises, challenge the commonly held beliefs, rule out many theoretical models, and point to a new path for raising T c even further.« less

Sr 2 IrO 4 : Gateway to cuprate superconductivity?

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

Mitchell, J. F.

2015-06-01

To understand the varied magnetic and electronic properties of 3d transition metal oxides (TMO), we routinely invoke a separability among charge-, spin- and orbital degrees of freedom, tightly coupled yet distinct sectors that can be identified, measured, and understood individually. But something interesting happens on the way down the Periodic Table—relativistic spin-orbit coupling (SOC) grows progressively stronger, blurring the lines among these spin, charge, and orbital sectors. SOC forces us to consider a different conceptual framework for 4d, and particularly 5d TMO systems, than has been sufficient for our present day understanding of 3d analogs. Ironically, this rethinking needed formore » 5d oxides may turn out to be critical to our understanding of one of 3d TMO’s greatest treasures – cuprate superconductivity — and in the process may lead us on a pathway to discovery of a new class of high-Tc materials.« less

Transport properties of stripe-ordered high T c cuprates

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

Jie, Qing; Han, Su Jung; Dimitrov, Ivo

Transport measurements provide important characterizations of the nature of stripe order in the cuprates. Initial studies of systems such as La 1.6-xNd 0.4Sr xCuO₄ demonstrated the strong anisotropy between in-plane and c-axis resistivities, but also suggested that stripe order results in a tendency towards insulating behavior within the planes at low temperature. More recent work on La 2-xBa xCuO₄ with x = 1/8 has revealed the occurrence of quasi-two-dimensional superconductivity that onsets with spin-stripe order. The suppression of three-dimensional superconductivity indicates a frustration of the interlayer Josephson coupling, motivating a proposal that superconductivity and stripe order are intertwined in amore » pair-density-wave state. Complementary characterizations of the low-energy states near the Fermi level are provided by measurements of the Hall and Nernst effects, each revealing intriguing signatures of stripe correlations and ordering. We review and discuss this work.« less

Deflocculants for Tape Casting Barium Titanate.

DTIC Science & Technology

1983-07-01

the individual components of our system in order to determine the effects of water on dispersion properties. The Karl Fischer reagent method (KFR) was...Determined by Karl Fischer Methods Ambient (%) (Dry) % Methyl Ethyl Ketone 0.0338 0.0068* Ethanol 5.1029 0.0161* REX-ethanol 1.8658 0.0059* Barium Titanate...glass jar prior to use. Residual moisture, as determined by Karl Fischer reagent methods , is indicated in Table 11. The Fisher reagent grade ethanol

Pair-density waves, charge-density waves, and vortices in high-Tc cuprates

NASA Astrophysics Data System (ADS)

Dai, Zhehao; Zhang, Ya-Hui; Senthil, T.; Lee, Patrick A.

2018-05-01

A recent scanning tunneling microscopy (STM) experiment reports the observation of a charge-density wave (CDW) with a period of approximately 8a in the halo region surrounding the vortex core, in striking contrast to the approximately 4a period CDWs that are commonly observed in the cuprates. Inspired by this work, we study a model where a bidirectional pair-density wave (PDW) with period 8 is at play. This further divides into two classes: (1) where the PDW is a competing state of the d -wave superconductor and can exist only near the vortex core where the d -wave order is suppressed and (2) where the PDW is the primary order, the so-called "mother state" that persists with strong phase fluctuations to high temperature and high magnetic field and lies behind the pseudogap phenomenology. We study the charge-density wave structures near the vortex core in these models. We emphasize the importance of the phase winding of the d -wave order parameter. The PDW can be pinned by the vortex core due to this winding and become static. Furthermore, the period-8 CDW inherits the properties of this winding, which gives rise to a special feature of the Fourier transform peak, namely, it is split in certain directions. There is also a line of zeros in the inverse Fourier transform of filtered data. We propose that these are key experimental signatures that can distinguish between the PDW-driven scenario from the more mundane option that the period-8 CDW is primary. We discuss the pro's and con's of the options considered above. Finally, we attempt to place the STM experiment in the broader context of pseudogap physics of underdoped cuprates and relate this observation to the unusual properties of x-ray scattering data on CDW carried out to very high magnetic field.

Assessment of Barium Sulphate Formation and Inhibition at Surfaces with Synchrotron X-ray Diffraction (SXRD)

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

E Mavredaki; A Neville; K Sorbie

2011-12-31

The precipitation of barium sulphate from aqueous supersaturated solutions is a well-known problem in the oil industry often referred to as 'scaling'. The formation and growth of barite on surfaces during the oil extraction process can result in malfunctions within the oil facilities and serious damage to the equipment. The formation of barium sulphate at surfaces remains an important topic of research with the focus being on understanding the mechanisms of formation and means of control. In situ synchrotron X-ray diffraction (SXRD) was used to investigate the formation of barium sulphate on a stainless steel surface. The effect of Poly-phosphinocarboxylicmore » acid (PPCA) and Diethylenetriamine-penta-methylenephosphonic acid (DETPMP) which are two commercial inhibitors for barium sulphate was examined. The in situ SXRD measurements allowed the identification of the crystal faces of the deposited barite in the absence and presence of the two inhibitors. The preferential effect of the inhibitors on some crystal planes is reported and the practical significance discussed.« less

Spectral K-edge subtraction imaging of experimental non-radioactive barium uptake in bone.

PubMed

Panahifar, Arash; Samadi, Nazanin; Swanston, Treena M; Chapman, L Dean; Cooper, David M L

2016-12-01

To evaluate the feasibility of using non-radioactive barium as a bone tracer for detection with synchrotron spectral K-edge subtraction (SKES) technique. Male rats of 1-month old (i.e., developing skeleton) and 8-month old (i.e., skeletally mature) were orally dosed with low dose of barium chloride (33mg/kg/day Ba 2+ ) for 4weeks. The fore and hind limbs were dissected for imaging in projection and computed tomography modes at 100μm and 52μm pixel sizes. The SKES method utilizes a single bent Laue monochromator to prepare a 550eV energy spectrum to encompass the K-edge of barium (37.441keV), for collecting both 'above' and 'below' the K-edge data sets in a single scan. The SKES has a very good focal size, thus limits the 'crossover' and motion artifacts. In juvenile rats, barium was mostly incorporated in the areas of high bone turnover such as at the growth plate and the trabecular surfaces, but also in the cortical bone as the animals were growing at the time of tracer administration. However, the adults incorporated approximately half the concentration and mainly in the areas where bone remodeling was predominant and occasionally in the periosteal and endosteal layers of the diaphyseal cortical bone. The presented methodology is simple to implement and provides both structural and functional information, after labeling with barium, on bone micro-architecture and thus has great potential for in vivo imaging of pre-clinical animal models of musculoskeletal diseases to better understand their mechanisms and to evaluate the efficacy of pharmaceuticals. Copyright © 2016 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Thermoelectric properties of the yttrium-doped ceramic oxide SrTiO3

NASA Astrophysics Data System (ADS)

Khan, Tamal Tahsin; Ur, Soon-Chul

2017-01-01

The doping dependence of the thermoelectric figure of merit, ZT, of the ceramic oxide SrTiO3 at high temperature has been studied. In this study, yttrium was used as the doping element. A conventional solid-state reaction method was used for the preparation of Y-doped SrTiO3. The doping level in SrTiO3 was controlled to be in the doping range of 2 - 10 mole%. Almost all the yttrium atoms incorporated into the SrTiO3 provided charge carriers, as was observed by using X-ray diffraction pattern. The relative densities of all the samples varied from 98.53% to 99.45%. The thermoelectric properties, including the electrical conductivity σ, Seebeck coefficient S, thermal conductivity k, and the figure of merit, ZT, were investigated at medium temperatures. The ZT value showed an obvious doping level dependence, in which a value as high as 0.18 is realized at 773 K for a doping of 8 mole%.

Synthesis and properties of nickel-doped nanocrystalline barium hexaferrite ceramic materials

NASA Astrophysics Data System (ADS)

Waqar, Moaz; Rafiq, Muhammad Asif; Mirza, Talha Ahmed; Khalid, Fazal Ahmad; Khaliq, Abdul; Anwar, Muhammad Sabieh; Saleem, Murtaza

2018-04-01

M-type barium hexaferrite ceramics have emerged as important materials both for technological and commercial applications. However, limited work has been reported regarding the investigation of nanocrystalline Ni-doped barium hexaferrites. In this study, nanocrystalline barium hexaferrite ceramics with the composition BaFe12- x Ni x O19 (where x = 0, 0.3 and 0.5) were synthesized by sol-gel method and characterized using X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, vibrating sample magnetometer and precision impedance analyzer. All the synthesized samples had single magnetoplumbite phase having space group P63/mmc showing the successful substitution of Ni in BaFe12O19 without the formation of any impurity phase. Average grain size of undoped samples was around 120 nm which increased slightly with the addition of Ni. Saturation magnetization ( M s) and remnant magnetization ( M r) increased with the addition of Ni, however, coercivity ( H c) decreased with the increase in Ni from x = 0 to x = 0.5. Real and imaginary parts of permittivity decreased with the increasing frequency and increased with Ni content. Dielectric loss and conductivity showed slight variation with the increase in Ni concentration.

The Skylab barium plasma injection experiments. I - Convection observations

NASA Technical Reports Server (NTRS)

Wescott, E. M.; Stenbaek-Nielsen, H. C.; Davis, T. N.; Peek, H. M.

1976-01-01

Two barium-plasma injection experiments were carried out during magnetically active periods in conjunction with the Skylab 3 mission. The high-explosive shaped charges were launched near dawn on November 27 and December 4, 1973, UT. In both cases, the AE index was near 400 gammas, and extensive pulsating auroras covered the sky. The first experiment, Skylab Alpha, occurred in the waning phase of a 1000-gamma substorm, and the second, Skylab Beta, occurred in the expansive phase of an 800-gamma substorm. In both, the convection was generally magnetically eastward, with 100-km-level electric fields near 40 mV/m. However, in the Alpha experiment the observed orientation of the barium flux tube fit theoretical field lines having no parallel current, but the Beta flux-tube orientation indicated a substantial upward parallel sheet current.

Ion beam irradiation of lanthanum and thorium-doped yttrium titanates

NASA Astrophysics Data System (ADS)

Lian, J.; Zhang, F. X.; Peters, M. T.; Wang, L. M.; Ewing, R. C.

2007-05-01

Y2Ti2O7 pyrochlores doped with La have been sintered at 1373 K for 12 h with the designed compositions of the (LaxY1-x)2Ti2O7 system (x = 0, 0.08, 0.5, and 1), and the phase compositions were analyzed by X-ray diffraction. Limited amounts of La were incorporated into yttrium titanate pyrochlore structure for La-doped samples; while, the end member composition of La2Ti2O7 formed a layered perovskite structure. Ion beam-induced amorphization occurred for all compositions in the (LaxY1-x)2Ti2O7 binary under 1 MeV Kr2+ irradiation at room temperature, and the critical amorphization dose decreased with increasing amounts of La3+. The critical amorphization temperatures for Y2Ti2O7, (La0.162Y0.838)2Ti2O7 and La2Ti2O7 were determined to be ∼780, 890 and 920 K, respectively. Th4+ and Fe3+-doped yttrium titanate pyrochlores were synthesized at 1373 K by sintering Y2Ti2O7 with (ThO2 + Fe2O3). Pyrochlore structures and the chemical compositions were primarily identified by the X-ray diffraction and energy dispersive X-ray (EDX) measurements. The lattice parameter and the critical amorphization dose (1 MeV Kr2+ at room temperature) increase for yttrium titanate pyrochlores with the addition of Th. The increasing 'resistance' to amorphization with less La and greater Th and Fe contents for (Y1-xLax)2Ti2O7 and Y2Ti2O7-Fe2O3-ThO2 systems, respectively, are consistent with the changes in the average ionic radius ratio at the A-sites and B-sites. These results suggest that the addition of lanthanides and actinides (e.g., Th, U, or Pu) will affect the structural stability, as well as the radiation response behavior of the pyrochlore structure-type.

Modified Barium Swallow for Evaluation of Dysphagia.

PubMed

Peterson, Rebecca

2018-01-01

Deglutition, or the act of swallowing, allows food and fluids to move through the upper gastrointestinal tract. Difficulty swallowing, known as dysphagia, causes a host of complications for patients. Fluoroscopic evaluation of dysphagia enables appropriate diagnosis and treatment. This evaluation commonly is accomplished with a swallowing dysfunction study, also known as a modified barium swallow procedure. © 2018 American Society of Radiologic Technologists.

Usefulness of high-density barium for detection of leaks after esophagogastrectomy, total gastrectomy, and total laryngectomy.

PubMed

Swanson, Jonathan O; Levine, Marc S; Redfern, Regina O; Rubesin, Stephen E

2003-08-01

The purpose of this study was to determine the usefulness of a high-density (250% weight/volume) barium compared with a water-soluble contrast agent for the detection of esophageal leaks in patients who had undergone esophagogastrectomy, total gastrectomy, or total laryngectomy. A search of our radiology database from 1998 to 2001 revealed 46 eligible radiographic studies performed using a water-soluble contrast agent alone or a water-soluble contrast agent followed by barium that showed leaks in patients who had undergone esophagogastrectomy, total gastrectomy, or total laryngectomy. The images were reviewed to determine the morphology of the leaks (i.e., blind-ending tracks, sealed-off collections, or free extravasation of contrast material). Medical records were also reviewed to determine whether detection of the leaks seen on the radiographic studies affected patient management. Of the 46 leaks seen on radiographic studies, 23 (50%) were detected with a water-soluble contrast agent and 23 (50%) were detected only with high-density barium. Of the 23 leaks visualized with water-soluble contrast media, six (26%) were characterized by blind-ending tracks, 14 (61%) by sealed-off collections, and three (13%) by free extravasation of contrast material into the mediastinum or neck. Of the 23 leaks visualized only with high-density barium, 19 (83%) were characterized by blind-ending tracks and four (17%) by sealed-off collections. Thus, leaks detected only on images obtained with high-density barium were significantly more likely to be characterized by blind-ending tracks than those detected on images obtained with a water-soluble contrast agent (p = 0.0007). Of the 33 patients with clinical follow-up, the findings seen on these imaging studies affected management in 12 (86%) of 14 patients with leaks depicted by water-soluble contrast media and in 10 (53%) of 19 with leaks depicted only by high-density barium. Our findings support the use of high-density barium as part

Study of the photovoltaic effect in thin film barium titanate

NASA Technical Reports Server (NTRS)

Grannemann, W. W.; Dharmadhikari, V. S.

1982-01-01

Ferroelectric films of barium titanate were synthesized on silicon and quartz substrates, and the photoelectric effect in the structure consisting of metal deposited ferroelectric barium titanate film silicon was studied. A photovoltage with polarity that depends on the direction of the remanent polarization was observed. The deposition of BaTiO3 on silicon and fused quartz substrates was accomplished by an rf sputtering technique. A series of experiments to study the growth of ferroelectric BaTiO3 films on single crystal silicon and fused quartz substrates were conducted. The ferroelectric character in these films was found on the basis of evidence from the polarization electric field hysteresis loops, capacitance voltage and capacitance temperature techniques and from X-ray diffraction studies.

Correlation among the effective mass (m*), λab and Tc of superconducting cuprates in a Casimir energy scenario

NASA Astrophysics Data System (ADS)

Orlando, M. T. D.; Rouver, A. N.; Rocha, J. R.; Cavichini, A. S.

2018-06-01

The relevance of the Casimir effect, discovered in 1948, has recently been pointed out in studies on materials such as graphene and high-temperature superconducting cuprates. In particular, the relationship between Casimir energy and the energy of a superconducting condensate with anisotropy characterized by high bidimensionality has already been discussed in certain theoretical scenarios. Using this proposal, this work describes the relationship between the effective mass of the charge carriers (m* = αme) and the macroscopic parameters characteristic of several families of high-Tc superconducting cuprates (Cu-HTSC) that have copper and oxygen superconducting planes (Cu-O). We have verified that an expression exists that correlates the effective mass, the London penetration length in the plane λab, the critical temperature Tc and the distance d between the equivalent superconducting planes of Cu-HTSC. This study revealed that the intersection between the asymptotic behavior of α as a function of Tc and the line describing the optimal value of α ≃ 2 (m* ≃ 2me) indicates that a nonadiabatic region exists, which implies a carrier-lattice interaction and where the critical temperature can have its highest value in Cu-HTSC.

Material and Doping Dependence of the Nodal and Antinodal Dispersion Renormalizations in Single- and Multilayer Cuprates

DOE PAGES

Johnston, S.; Lee, W. S.; Chen, Y.; ...

2010-01-01

We presenmore » t a review of bosonic renormalization effects on electronic carriers observed from angle-resolved photoemission spectra in the cuprates. Specifically, we discuss the viewpoint that these renormalizations represent coupling of the electrons to the lattice and review how materials dependence, such as the number of Cu O 2 layers, and doping dependence can be understood straightforwardly in terms of several aspects of electron-phonon coupling in layered correlated materials.« less

Magnetocrystalline anisotropy of Fe2 + ion in silicon- or germanium-substituted yttrium iron garnet at zero temperature

NASA Astrophysics Data System (ADS)

Rudowicz, Czeslaw

1982-01-01

The present work reports the theoretical considerations of the magnetocrystalline anisotropy of ferrous ions induced by tetravalent dopants in yttrium iron garnet. Using the spin Hamiltonian developed earlier by us and the molecular field (h) approximation we derive the cubic anisotropy constants K1 and K2 at zero temperature. We adopt the Alben's et al. model of twelve inequivalent Fe2+ sites in silicon-substituted yttrium iron garnet. Results are given for h = 400, 300, 200 and the spin Hamiltonian parameters with the trigonal Δ = 300, 400, 500, 600, 700 and the nontrigonal crystal field parameter Γ = 200, 300 cm-1. The agreement with the experimental K1 and K2 is quite good. The discussion reveals that the properties of the far and near sites in the two-center model can now be theoretically explained. The theoretical ratios of K1(far) to K1(near) agree well with experiment. Thus our results speak in favor of the orbital singlet rather than the doublet model assumed previously for Fe2+ in silicon- or germanium-substituted yttrium iron garnets.

Influence of Yttrium Ion-Implantation on the Growth Kinetics and Micro-Structure of NiO Oxide Film

NASA Astrophysics Data System (ADS)

Jin, Huiming; Adriana, Felix; Majorri, Aroyave

2008-02-01

Isothermal and cyclic oxidation behaviours of pure and yttrium-implanted nickel were studied at 1000°C in air. Scanning electronic microscopy (SEM) and transmission electronic microscopy (TEM) were used to examine the micro-morphology and structure of oxide scales formed on the nickel substrate. It was found that Y-implantation significantly improved the anti-oxidation ability of nickel in both isothermal and cyclic oxidizing experiments. Laser Raman microscopy was also used to study the stress status of oxide scales formed on nickel with and without yttrium. The main reason for the improvement in anti-oxidation of nickel was that Y-implantation greatly reduced the growing speed and grain size of NiO. This fine-grained NiO oxide film might have better high temperature plasticity and could relieve parts of compressive stress by means of creeping, and maintained a ridge character and a relatively low internal stress level. Hence yttrium ion-implantation remarkably enhanced the adhesion of protective NiO oxide scale formed on the nickel substrate.

The barium-to-iron enrichment versus age relation of ancient disc stars

NASA Astrophysics Data System (ADS)

Fuhrmann, K.; Chini, R.; Kaderhandt, L.; Chen, Z.; Lachaume, R.

2017-11-01

We report an intrinsically precise relation of the barium-to-iron enrichment as a function of age for a local, volume-complete (N = 30) sample of ancient Population II (τ ≥ 12 Gyr) and intermediate-disc stars (τ ≃ 10 Gyr), which suggests a common, r-process-dominated nucleosynthesis site for both elements in the early stages of the Milky Way. Deviants from this empirical relation are to a large extent identified as formerly known or new blue straggler stars. We report in particular the striking case of the Population II star HD 159062, whose barium overabundance is difficult to explain without wind accretion of s-process material from a former asymptotic giant branch (AGB) primary that very likely survived as a white dwarf companion. The weak but significant barium enhancement that we measure for HR 3578 and 104 Tau also suggests that both may be accompanied by faint degenerate companions. If confirmed through precision astrometry or direct imaging observations, this would mean a very efficient method to uncover ancient stellar remnant companions around solar-type stars.

Electrodeposition of titania and barium titanate thin films for high dielectric applications

NASA Astrophysics Data System (ADS)

Roy, Biplab Kumar

In order to address the requirement of a low-temperature low-cost cost processing for depositing high dielectric constant ceramic films for applications in embedded capacitor and flexible electronics technology, two different chemical bath processes, namely, thermohydrolytic deposition (TD) and cathodic electrodeposition (ED) have been exploited to generate titania thin films. In thermohydrolytic deposition technique, titania films were generated from acidic aqueous solution of titanium chloride on F: SnO2 coated glass and Si substrates by temperature assisted hydrolysis mechanism. On the other hand, in cathodic electrodeposition, in-situ electro-generation of hydroxyl ions triggered a fast deposition of titania on conductive substrates such as copper and F: SnO2 coated glass from peroxotitanium solution at low temperatures (˜0°C). In both techniques, solution compositions affected the morphology and crystallinity of the films. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques have been employed to perform such characterization. As both processes utilized water as solvent, the as-deposited films contained hydroxyl ligand or physically adsorbed water molecules in the titania layer. Besides that, electrodeposited films contained peroxotitanium bonds which were characterized by FTIR studies. Although as-electrodeposited titania films were X-ray amorphous, considerable crystallinity could be generated by heat treatment. The films obtained from both the processes showed v moderately high dielectric constant (ranging from 9-30 at 100 kHz) and high breakdown voltage (0.09-0.15 MV/cm) in electrical measurements. To further improve the dielectric constant, electrodeposited titania films were converted to barium titanate films in high pH barium ion containing solution at 80-90°C. The resultant film contained cubic crystalline barium titanate verified by XRD analysis. Simple low-temperature hydrothermal technique of conversion worked

Commensurate antiferromagnetic excitations as a signature of the pseudogap in the tetragonal high-T c cuprate HgBa 2CuO 4+δ

DOE PAGES

Chan, M. K.; Dorow, C. J.; Mangin-Thro, L.; ...

2016-03-04

We report that antiferromagnetic correlations have been argued to be the cause of the d-wave superconductivity and the pseudogap phenomena exhibited by the cuprates. Although the antiferromagnetic response in the pseudogap state has been reported for a number of compounds, there exists no information for structurally simple HgBa 2CuO 4+δ. We report neutron-scattering results for HgBa 2CuO 4+δ (superconducting transition temperature T c≈71 K, pseudogap temperature T*≈305 K) that demonstrate the absence of the two most prominent features of the magnetic excitation spectrum of the cuprates: the X-shaped ‘hourglass’ response and the resonance mode in the superconducting state. Instead, themore » response is Y-shaped, gapped and significantly enhanced below T*, and hence a prominent signature of the pseudogap state.« less

Atomic-scale electronic structure of the cuprate d-symmetry form factor density wave state

DOE PAGES

M. H. Hamidian; Kim, Chung Koo; Edkins, S. D.; ...

2015-10-26

Research on high-temperature superconducting cuprates is at present focused on identifying the relationship between the classic ‘pseudogap’ phenomenon 1, 2 and the more recently investigated density wave state 3–13. This state is generally characterized by a wavevector Q parallel to the planar Cu–O–Cu bonds 4–13 along with a predominantly d-symmetry form factor 14–17 (dFF-DW). To identify the microscopic mechanism giving rise to this state 18–30, one must identify the momentum-space states contributing to the dFF-DW spectral weight, determine their particle–hole phase relationship about the Fermi energy, establish whether they exhibit a characteristic energy gap, and understand the evolution of allmore » these phenomena throughout the phase diagram. Here we use energy-resolved sublattice visualization 14 of electronic structure and reveal that the characteristic energy of the dFF-DW modulations is actually the ‘pseudogap’ energy Δ 1. Moreover, we demonstrate that the dFF-DW modulations at E = –Δ 1 (filled states) occur with relative phase π compared to those at E = Δ 1 (empty states). Lastly, we show that the conventionally defined dFF-DW Q corresponds to scattering between the ‘hot frontier’ regions of momentum-space beyond which Bogoliubov quasiparticles cease to exist 30–32. These data indicate that the cuprate dFF-DW state involves particle–hole interactions focused at the pseudogap energy scale and between the four pairs of ‘hot frontier’ regions in momentum space where the pseudogap opens.« less

Highly aligned arrays of high aspect ratio barium titanate nanowires via hydrothermal synthesis

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

Bowland, Christopher C.; Zhou, Zhi; Malakooti, Mohammad H.

2015-06-01

We report on the development of a hydrothermal synthesis procedure that results in the growth of highly aligned arrays of high aspect ratio barium titanate nanowires. Using a multiple step, scalable hydrothermal reaction, a textured titanium dioxide film is deposited on titanium foil upon which highly aligned nanowires are grown via homoepitaxy and converted to barium titanate. Scanning electron microscope images clearly illustrate the effect the textured film has on the degree of orientation of the nanowires. The alignment of nanowires is quantified by calculating the Herman's Orientation Factor, which reveals a 58% improvement in orientation as compared to growthmore » in the absence of the textured film. The ferroelectric properties of barium titanate combined with the development of this scalable growth procedure provide a powerful route towards increasing the efficiency and performance of nanowire-based devices in future real-world applications such as sensing and power harvesting.« less

Plasma irregularities caused by cycloid bunching of the CRRES G-2 barium release

NASA Technical Reports Server (NTRS)

Bernhardt, P. A.; Huba, J. D.; Pongratz, M. B.; Simons, D. J.; Wolcott, J. H.

1993-01-01

The Combined Release and Radiation Effects Satellite (CRRES) spacecraft carried a number of barium thermite canisters for release into the upper atmosphere. The barium release labeled G-2 showed evidence of curved irregularities not aligned with the ambient magnetic field B. The newly discovered curved structures can be explained by a process called cycloid bunching. Cycloid bunching occurs when plasma is created by photoionization of a neutral cloud injected at high velocity perpendicular to B. If the injection velocity is much larger than the expansion speed of the cloud, the ion trail will form a cycloid that has irregularities spaced by the product of the perpendicular injection speed and the ion gyroperiod, Images of the solar-illuminated barium ions are compared with the results of a three-dimensional kinetic simulation. Cycloid bunching is shown to be responsible for the rapid generation of both curved and field-aligned irregularities in the CRRES G-2 experiment.

Theoretical study of phonon dispersion, elastic, mechanical and thermodynamic properties of barium chalcogenides

NASA Astrophysics Data System (ADS)

Musari, A. A.; Orukombo, S. A.

2018-03-01

Barium chalcogenides are known for their high-technological importance and great scientific interest. Detailed studies of their elastic, mechanical, dynamical and thermodynamic properties were carried out using density functional theory and plane-wave pseudo potential method within the generalized gradient approximation. The optimized lattice constants were in good agreement when compared with experimental data. The independent elastic constants, calculated from a linear fit of the computed stress-strain function, were used to determine the Young’s modulus (E), bulk modulus (B), shear modulus (G), Poisson’s ratio (σ) and Zener’s anisotropy factor (A). Also, the Debye temperature and sound velocities for barium chalcogenides were estimated from the three independent elastic constants. The calculations of phonon dispersion showed that there are no negative frequencies throughout the Brillouin zone. Hence barium chalcogenides have dynamically stable NaCl-type crystal structure. Finally, their thermodynamic properties were calculated in the temperature range of 0-1000 K and their constant-volume specific heat capacities at room-temperature were reported.

Dual structure in the charge excitation spectrum of electron-doped cuprates

NASA Astrophysics Data System (ADS)

Bejas, Matías; Yamase, Hiroyuki; Greco, Andrés

2017-12-01

Motivated by the recent resonant x-ray scattering (RXS) and resonant inelastic x-ray scattering (RIXS) experiments for electron-doped cuprates, we study the charge excitation spectrum in a layered t -J model with the long-range Coulomb interaction. We show that the spectrum is not dominated by a specific type of charge excitations, but by different kinds of charge fluctuations, and is characterized by a dual structure in the energy space. Low-energy charge excitations correspond to various types of bond-charge fluctuations driven by the exchange term (J term), whereas high-energy charge excitations are due to usual on-site charge fluctuations and correspond to plasmon excitations above the particle-hole continuum. The interlayer coupling, which is frequently neglected in many theoretical studies, is particularly important to the high-energy charge excitations.

Magnetic studies of cobalt doped barium hexaferrite nanoparticles prepared by modified sol-gel method

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

Shalini, M. Govindaraj; Sahoo, Subasa C., E-mail: subasa@cukerala.ac.in

2016-05-06

M-type barium hexaferrite (BaFe{sub 12}O{sub 19}) and cobalt doped barium hexaferrite (BaFe{sub 11}CoO{sub 19}) nanopowders were synthesized by modified sol-gel auto-combustion technique and were annealed at 900°C in air for 4 hours. The annealed powders were studied in the present work and X-ray diffraction studies showed pure phase formation after annealing. The average grain size in the nanopowder sample was decreased after doping. Magnetization value of 60 emu/g was observed at 300 K for the barium hexaferrite and was reduced to 54 emu/g after doping. The coercivity of 5586 Oe was observed at 300 K for the undoped sample andmore » was found to be decreased in the doped sample. As the measurement temperature was decreased from 300 K to 60 K, magnetization value was increased in both the samples compared to those at 300 K. The coercivity of the undoped sample was found to decrease whereas it was increased for the doped sample at 60 K. The observed magnetic properties may be understood on the basis of modified exchange interaction and anisotropy in the doped sample compared to that of pure barium hexaferrite.« less

The Interaction Between Accretion from the Interstellar Medium and Accretion from the Evolved Binary Component in Barium Stars

NASA Astrophysics Data System (ADS)

Jeong, Yeuncheol; Yushchenko, Alexander V.; Doikov, Dmytry N.

2018-03-01

The reanalysis of the previously published abundance pattern of mild barium star HD202109 (ζ Cyg) and the chemical compositions of 129 thin disk barium stars facilitated the search for possible correlations of different stellar parameters with second ionization potentials of chemical elements. Results show that three valuable correlations exist in the atmospheres of barium stars. The first is the relationship between relative abundances and second ionization potentials. The second is the age dependence of mean correlation coefficients of relative abundances vs. second ionization potentials, and the third one is the changes in correlation coefficients of relative abundances vs. second ionization potentials as a function of stellar spatial velocities and overabundances of s-process elements. These findings demonstrate the possibility of hydrogen and helium accretion from the interstellar medium on the atmospheres of barium stars.

Effect of barium sulfate contrast medium on rheology and sensory texture attributes in a model food.

PubMed

Ekberg, O; Bulow, M; Ekman, S; Hall, G; Stading, M; Wendin, K

2009-03-01

The swallowing process can be visualized using videoradiography, by mixing food with contrast medium, e.g., barium sulfate (BaSO(4)), making it radiopaque. The sensory properties of foods may be affected by adding this medium. To evaluate if and to what extent sensory and rheological characteristics of mango purée were altered by adding barium sulfate to the food. This study evaluated four food samples based on mango purée, with no or added barium sulfate contrast medium (0%, 12.5%, 25.0%, and 37.5%), by a radiographic method, and measured sensory texture properties and rheological characteristics. The sensory evaluation was performed by an external trained panel using quantitative descriptive analysis. The ease of swallowing the foods was also evaluated. The sensory texture properties of mango purée were significantly affected by the added barium in all evaluated attributes, as was the perception of particles. Moreover, ease of swallowing was significantly higher in the sample without added contrast medium. All samples decreased in extensional viscosity with increasing extension rate, i.e., all samples were tension thinning. Shear viscosity was not as dependent on the concentration of BaSO(4) as extensional viscosity. Addition of barium sulfate to a model food of mango purée has a major impact on perceived sensory texture attributes as well as on rheological parameters.

Dielectric function for doped graphene layer with barium titanate

NASA Astrophysics Data System (ADS)

Martinez Ramos, Manuel; Garces Garcia, Eric; Magana, Fernado; Vazquez Fonseca, Gerardo Jorge

2015-03-01

The aim of our study is to calculate the dielectric function for a system formed with a graphene layer doped with barium titanate. Density functional theory, within the local density approximation, plane-waves and pseudopotentials scheme as implemented in Quantum Espresso suite of programs was used. We considered 128 carbon atoms with a barium titanate cluster of 11 molecules as unit cell with periodic conditions. The geometry optimization is achieved. Optimization of structural configuration is performed by relaxation of all atomic positions to minimize their total energies. Band structure, density of states and linear optical response (the imaginary part of dielectric tensor) were calculated. We thank Dirección General de Asuntos del Personal Académico de la Universidad Nacional Autónoma de México, partial financial support by Grant IN-106514 and we also thank Miztli Super-Computing center the technical assistance.

HR 6094: A Young, Solar-Type, Solar-Metallicity Barium Dwarf Star

NASA Astrophysics Data System (ADS)

Porto de Mello, G. F.; da Silva, L.

1997-02-01

The young solar-type star HR 6094 is found to be a barium dwarf, overabundant in the s-process elements as well as deficient in C. It is a member of the solar-metallicity, 0.3 Gyr old Ursa Major kinematical group. Measurements of radial velocity and ultraviolet flux do not support the attribution of such abundance anomalies to an unseen degenerate companion. A common proper motion, V = 10, DA white dwarf (WD), located 5360 AU away, however, strongly supports the explanation of the origin of this barium star by the process of mass transfer in a binary system, in which the secondary component accreted matter from the primary one (now the WD) when it was an asymptotic giant branch (AGB) star self-enriched in the s-process elements. The membership in the UMa group of another s-process-rich and C-deficient star, HR 2047, suggests that these stars could have formed a multiple system in the past, which was disrupted by the mass-loss episode of the former AGB star. Their [C/Fe] deficiency could be explained by the action of the hot-bottomed envelope burning process in the late AGB, thereby reconverting it from a C-rich to an O-rich star, depleting C while enriching its envelope with Li and neutron capture elements. This is the first identification of the barium phenomenon in a near-zero-age star, besides being the first barium system in which the remnant of the late AGB star responsible for the heavy-element enrichment may have been directly spotted. Observations collected at the Cerro Tololo Inter-American Observatory (CTIO), Chile, and at the Observatório do Pico dos Dias, operated by the CNPq/Laboratório Nacional de Astrofísica, Brazil.

Flux pinning in yttrium barium copper oxide coated conductors

NASA Astrophysics Data System (ADS)

Chen, Zhijun

High quality high-temperature-superconducting YBa2Cu 3O7-x (YBCO) films for industrial applications demand very high critical current densities Jc, which can only be achieved by strong three-dimensional (3D) pinning with deliberately introduced nano-precipitates. The purpose of this thesis is to provide an in-depth understanding of the 3D pinning in such YBCO films. In pulsed laser deposition (PLD) prepared YBCO films, a high density of anti-phase boundaries and stacking faults were found to be effective pinning defects for improving Jc in small fields. However, their failure to improve Jc at high fields shows that such naturally generated defects are not strong 3D pinning centers. A demonstration of strong 3D pinning was found in a metal organic chemical vapor deposition (MOCVD) grown YBCO coated conductor (CC) with a high density of (Y,Sm)2O3 nano-precipitates. We observed a significantly enhanced irreversibility field Hirr which, like other superconducting properties was independent of thickness, due to strong vortex-pin interactions. The advantage of 3D pinning was further illustrated by a bi-layer metalorganic deposition (MOD) grown YBCO CC with different 3D pinning structures in each layer. The Jc anisotropy of the bilayer was found to be the thickness-weighted sum of the anisotropy of the two individual layers, demonstrating an applicable way to tune the Jcanisotropy. Moreover, extensive low temperature and high magnetic field evaluations performed on an MOCVD CC with dense 3D (Y,Sm) 2O3 nano-precipitate pinning centers showed that its strong vortex pinning at 77 K correlated well to strong performance at 4.2 K too. YBCO films with quantitatively controlled artificial Y2O 3 nano-precipitates were also grown by PLD, and characterized over wide temperature and field ranges. Their Jc was found to be determined by the vortex pinning mediated by thermal fluctuation effects. In weak thermal-fluctuation situations Jc increased with decreasing effective precipitate spacing Lc. In other situations, Jc depends on both Lc and the size and elementary pinning strength of the nano-precipitates. In summary, this thesis presents detailed pinning studies on several differently grown YBCO films. Our results identify the optimum pinning structures in YBCO films and provide a systematic guidance for optimizing vortex pinning.

Distribution and source of barium in ground water at Cattaraugus Indian Reservation, southwestern New York

USGS Publications Warehouse

Moore, R.B.; Staubitz, W.W.

1984-01-01

High concentrations of dissolved barium have been found in ground water from bedrock wells on the Seneca Nation of Indians Reservation on Cattaraugus Creek in southwestern New York. Concentrations in 1982 were as high as 23.0 milligrams per liter , the highest found reported from any natural ground-water system in the world. The highest concentrations are in a bedrock aquifer and in small lenses of saturated gravel between bedrock and the overlying till. The bedrock aquifer is partly confined by silt, clay, and till. The high barium concentrations are attributed to dissolution of the mineral barite (BaSO4), which is present in the bedrock and possibly in overlying silt, clay, or till. The dissolution of barite seems to be controlled by action of sulfate-reducing bacteria, which alter the BaSO4 equilibrium by removing sulfate ions and permitting additional barite to dissolve. Ground water from the surficial, unconsolidated deposits and surface water in streams contain little or no barium. Because barium is chemically similar to calcium, it probably could be removed by cation exchange or treatments similar to those used for water softening. (USGS)

Strontium and barium isotopes in presolar silicon carbide grains measured with CHILI-two types of X grains

NASA Astrophysics Data System (ADS)

Stephan, Thomas; Trappitsch, Reto; Davis, Andrew M.; Pellin, Michael J.; Rost, Detlef; Savina, Michael R.; Jadhav, Manavi; Kelly, Christopher H.; Gyngard, Frank; Hoppe, Peter; Dauphas, Nicolas

2018-01-01

We used CHILI, the Chicago Instrument for Laser Ionization, a new resonance ionization mass spectrometer developed for isotopic analysis of small samples, to analyze strontium, zirconium, and barium isotopes in 22 presolar silicon carbide grains. Twenty of the grains showed detectable strontium and barium, but none of the grains had enough zirconium to be detected with CHILI. Nine grains were excluded from further consideration since they showed very little signals (<1000 counts) for strontium as well as for barium. Among the 11 remaining grains, we found three X grains. The discovery of three supernova grains among only 22 grains was fortuitous, because only ∼1% of presolar silicon carbide grains are type X, but was confirmed by silicon isotopic measurements of grain residues with NanoSIMS. While one of the X grains showed strontium and barium isotope patterns expected for supernova grains, the two other supernova grains have 87Sr/86Sr < 0.5, values never observed in any natural sample before. From their silicon isotope ratios, the latter two grains can be classified as X2 grains, while the former grain belongs to the more common X1 group. The differences of these grains in strontium and barium isotopic composition constrain their individual formation conditions in Type II supernovae.

Multiple electrical phase transitions in Al substituted barium hexaferrite

NASA Astrophysics Data System (ADS)

Kumar, Sunil; Supriya, Sweety; Kar, Manoranjan

2017-12-01

Barium hexaferrite is known to be a very good ferromagnetic material. However, it shows very good dielectric properties, i.e., the dielectric constant is comparable to that of the ferroelectric material. However, its crystal symmetry does not allow it to be a ferroelectric material. Hence, the electrical properties have revived the considerable research interest on these materials, not only for academic interest, but also for technological applications. There are a few reports on temperature dependent dielectric behavior of these materials. However, the exact cause of dielectric as well as electrical conductivity is yet to be established. Hence, Al (very good conducting material) substituted barium hexaferrite (BaFe12-xAlxO19, x = 0.0-4.0) has been prepared by following the modified sol-gel method to understand the ac and DC electrical properties of these materials. The crystal structure and parameters have been studied by employing the XRD and FTIR techniques. There are two transition temperatures, which have been observed in the temperature dependent ac dielectric and DC resistivity measurement. The response of dielectric behaviors to temperature is similar to that of the ferroelectric material; however, the dielectric polarization is due to the polaron hopping, which is evident from the DC resistivity analysis. Hence, the present observations lead to understand the electrical properties of barium hexaferrite. The frequency dependent dielectric dispersion can be understood by the modified Debye model. More interestingly, the dielectric constant decreases and DC resistivity increases with the increase in the Al concentration, which has the correlation between bond length modifications in the crystal due to substitution.

Short-cavity squeezing in barium

NASA Technical Reports Server (NTRS)

Hope, D. M.; Bachor, H-A.; Manson, P. J.; Mcclelland, D. E.

1992-01-01

Broadband phase sensitive noise and squeezing were experimentally observed in a system of barium atoms interacting with a single mode of a short optical cavity. Squeezing of 13 +/- 3 percent was observed. A maximum possible squeezing of 45 +/- 8 percent could be inferred for out experimental conditions, after correction for measured loss factors. Noise reductions below the quantum limit were found over a range of detection frequencies 60-170 MHz and were best for high cavity transmission and large optical depths. The amount of squeezing observed is consistent with theoretical predictions from a full quantum statistical model of the system.

Initial Investigation of Factors Influencing Radiation Dose to Patients Undergoing Barium-Based Fluoroscopy Procedures in Tanzania.

PubMed

Ngaile, J E; Msaki, P K; Kazema, R R; Schreiner, L J

2017-04-25

The aim of this study was to investigate the nature and causes of radiation dose imparted to patients undergoing barium-based X-ray fluoroscopy procedures in Tanzania and to compare these doses to those reported in the literature from other regions worldwide. The air kerma area product (KAP) to patient undergoing barium investigations of gastrointestinal tract system was obtained from four consultant hospitals. The KAP was determined using a flat transparent transmission ionization chamber. Mean values of KAP for barium swallow (BS), barium meal (BM) and barium enema (BE) were 2.79, 2.62 and 15.04 Gy cm2, respectively. The mean values of KAP per hospital for the BS, BM and BE procedures varied by factors of up to 7.3, 1.6 and 2.0, respectively. The overall difference between individual patient doses across the four consultant hospitals investigated differed by factors of up to 53, 29.5 and 12 for the BS, BM and BE procedures, respectively. The majority of the mean values of KAP was lower than the reported values for Ghana, Greece, Spain and the UK, while slightly higher than those reported for India. The observed wide variation of KAP values for the same fluoroscopy procedure within and among the hospitals was largely attributed to the dynamic nature of the procedures, the patient characteristics, the skills and experience of personnel, and the different examination protocols employed among hospitals. The observed great variations of procedural protocols and patient doses within and across the hospitals call for the need to standardize examination protocols and optimize barium-based fluoroscopy procedures. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Implications of Barium Abundances for the Chemical Enrichment of Dwarf Galaxies

NASA Astrophysics Data System (ADS)

Duggan, Gina; Kirby, Evan N.

2018-06-01

There are many candidate sites of the r-process: core-collapse supernovae (including rare magnetorotational core-collapse supernovae), neutron star mergers (NSMs), and neutron star/black hole mergers. The chemical enrichment of galaxies—specifically dwarf galaxies—helps distinguish between these sources based on the continual build-up of r-process elements. The existence of several nearby dwarf galaxies allows us to measure robust chemical abundances for galaxies with different star formation histories. Dwarf galaxies are especially useful because simple chemical evolution models can be used to determine the sources of r-process material. We have measured the r-process element barium with Keck/DEIMOS medium-resolution spectroscopy. We will present the largest sample of barium abundances (more than 200 stars) in dwarf galaxies ever assembled. We measure [Ba/Fe] as a function of [Fe/H] in this sample and compare with existing [alpha/Fe] measurements. We have found that a large contribution of barium needs to occur at timescales similar to Type Ia supernovae in order to recreate our observed abundances, namely the flat or slightly rising trend of [Ba/Fe] vs. [Fe/H]. We conclude that neutron star mergers are the main contribution of r-process enrichment in dwarf galaxies.

Barium strontium titanate thin film growth with variation of lanthanum dopant compatibility as sensor prototype in the satellite technology

NASA Astrophysics Data System (ADS)

Mulyadi; Wahyuni, Rika; Hardhienata, Hendradi; Irzaman

2018-05-01

Electrical properties of barium strontium titanate thin films were investigated. Three layers of barium strontium titanate thin films have been prepared by chemical solution deposition method and spin coating technique at 8000 rpm rotational speed for 30 seconds and temperature of annealing at 850°C for eight hours with temperature increment of 1.67°C/minute. Materials produced by the process of lanthanum dopant with doping variations of 2%, 4% and 6% above type-p silicon (100) substrates. Film obtained was then carried out the characterization using USB 2000 VIS-NIR and tauc plot method. As a result, the barium strontium titanate thin film has the value of band gap energy of 1.58 eV, 1.92 eV and 2.24 eV respectively. The characterization of electrical properties shows that the band gap value of barium strontium titanate thin film with lanthanum dopant was in the range of semiconductor value. Barium strontium titanate thin films with lanthanum dopant are sensitive to temperature changes, so it potentially to be applied to temperature monitoring on satellite technology.

21 CFR 201.304 - Tannic acid and barium enema preparations.

Code of Federal Regulations, 2011 CFR

2011-04-01

... added to barium enemas to improve X-ray pictures. Tannic acid is capable of causing diminished liver... use in enemas. Tannic acid for rectal use to enhance X-ray visualization is regarded as a new drug...

High-spin europium and gadolinium centers in yttrium-aluminum garnet

NASA Astrophysics Data System (ADS)

Vazhenin, V. A.; Potapov, A. P.; Asatryan, G. R.; Uspenskaya, Yu. A.; Petrosyan, A. G.; Fokin, A. V.

2016-08-01

Electron-spin resonance spectra of Eu2+ and Gd3+ centers substituting Y3+ ions in single-crystal yttrium-aluminum garnet have been studied and the parameters of their rhombic spin Hamiltonian have been determined. The fine-structure parameters of the above ions have been calculated in the superposition model disregarding changes in the angular coordinates of the ligand environment of the impurity defect thus demonstrating the necessity of taking these changes into account.

Atomic emission spectrometer/spectrograph for the determination of barium in microamounts of diatom ash

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

Bankston, D.C.; Fisher, N.S.

1977-06-01

The development and routine application of a method for the determination of trace levels of barium in microsamples (5-10 mg) of diatom ash is described Acid-dissolved lithium metaborate fusion melts of ash samples are analyzed using a spectrometer/spectrograph equipped with a dc argon plasma jet excitation source and an echelle diffraction grating. Sample, standard, and blank solutions are buffered by lithium contributed by the flux, to a degree sufficient to reduce matrix effects to acceptable levels. Previous barium determinations by other analytical techniques, on seven interlaboratory reference materials, have been used to establish the accuracy of our results. The averagemore » relative standard deviation for the instrumental analyses was 0.07. Using recommended instrument settings, moreover, the lowest concentration of barium visible in synthetic standard solutions lies just below 2 ..mu..g/L, which is equivalent to 2 ..mu..g/g in the ash.« less

Enhanced constitutive invasion activity in human nontumorigenic keratinocytes exposed to a low level of barium for a long time.

PubMed

Thang, Nguyen D; Yajima, Ichiro; Ohnuma, Shoko; Ohgami, Nobutaka; Kumasaka, Mayuko Y; Ichihara, Gaku; Kato, Masashi

2015-02-01

We have recently demonstrated that exposure to barium for a short time (≤4 days) and at a low level (5 µM = 687 µg/L) promotes invasion of human nontumorigenic HaCaT cells, which have characteristics similar to those of normal keratinocytes, suggesting that exposure to barium for a short time enhances malignant characteristics. Here we examined the effect of exposure to low level of barium for a long time, a condition mimicking the exposure to barium through well water, on malignant characteristics of HaCaT keratinocytes. Constitutive invasion activity, focal adhesion kinase (FAK) protein expression and activity, and matrix metalloproteinase 14 (MMP14) protein expression in primary cultured normal human epidermal keratinocytes, HaCaT keratinocytes, and HSC5 and A431 human squamous cell carcinoma cells were augmented following an increase in malignancy grade of the cells. Constitutive invasion activity, FAK phosphorylation, and MMP14 expression levels of HaCaT keratinocytes after treatment with 5 µM barium for 4 months were significantly higher than those of control untreated HaCaT keratinocytes. Taken together, our results suggest that exposure to a low level of barium for a long time enhances constitutive malignant characteristics of HaCaT keratinocytes via regulatory molecules (FAK and MMP14) for invasion. © 2013 Wiley Periodicals, Inc.

Electrolytic Deposition and Diffusion of Lithium onto Magnesium-9 Wt Pct Yttrium Bulk Alloy in Low-Temperature Molten Salt of Lithium Chloride and Potassium Chloride

NASA Astrophysics Data System (ADS)

Dong, Hanwu; Wu, Yaoming; Wang, Lidong; Wang, Limin

2009-10-01

The electrolytic deposition and diffusion of lithium onto bulk magnesium-9 wt pct yttrium alloy cathode in molten salt of 47 wt pct lithium chloride and 53 wt pct potassium chloride at 693 K were investigated. Results show that magnesium-yttrium-lithium ternary alloys are formed on the surface of the cathodes, and a penetration depth of 642 μm is acquired after 2 hours of electrolysis at the cathodic current density of 0.06 A·cm-2. The diffusion of lithium results in a great amount of precipitates in the lithium containing layer. These precipitates are the compound of Mg41Y5, which arrange along the grain boundaries and hinder the diffusion of lithium, and solid solution of yttrium in magnesium. The grain boundaries and the twins of the magnesium-9 wt pct yttrium substrate also have negative effects on the diffusion of lithium.

Radiographic Response to Yttrium-90 Radioembolization in Anterior Versus Posterior Liver Segments

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

Ibrahim, Saad M.; Lewandowski, Robert J.; Ryu, Robert K.

2008-11-15

The purpose of our study was to determine if preferential radiographic tumor response occurs in tumors located in posterior versus anterior liver segments following radioembolization with yttrium-90 glass microspheres. One hundred thirty-seven patients with chemorefractory liver metastases of various primaries were treated with yttrium-90 glass microspheres. Of these, a subset analysis was performed on 89 patients who underwent 101 whole-right-lobe infusions to liver segments V, VI, VII, and VIII. Pre- and posttreatment imaging included either triphasic contrast material-enhanced CT or gadolinium-enhanced MRI. Responses to treatment were compared in anterior versus posterior right lobe lesions using both RECIST and WHO criteria.more » Statistical comparative studies were conducted in 42 patients with both anterior and posterior segment lesions using the paired-sample t-test. Pearson correlation was used to determine the relationship between pretreatment tumor size and posttreatment tumor response. Median administered activity, delivered radiation dose, and treatment volume were 2.3 GBq, 118.2 Gy, and 1,072 cm{sup 3}, respectively. Differences between the pretreatment tumor size of anterior and posterior liver segments were not statistically significant (p = 0.7981). Differences in tumor response between anterior and posterior liver segments were not statistically significant using WHO criteria (p = 0.8557). A statistically significant correlation did not exist between pretreatment tumor size and posttreatment tumor response (r = 0.0554, p = 0.4434). On imaging follow-up using WHO criteria, for anterior and posterior regions of the liver, (1) response rates were 50% (PR = 50%) and 45% (CR = 9%, PR = 36%), and (2) mean changes in tumor size were -41% and -40%. In conclusion, this study did not find evidence of preferential radiographic tumor response in posterior versus anterior liver segments treated with yttrium-90 glass microspheres.« less

Radiographic response to yttrium-90 radioembolization in anterior versus posterior liver segments.

PubMed

Ibrahim, Saad M; Lewandowski, Robert J; Ryu, Robert K; Sato, Kent T; Gates, Vanessa L; Mulcahy, Mary F; Kulik, Laura; Larson, Andrew C; Omary, Reed A; Salem, Riad

2008-01-01

The purpose of our study was to determine if preferential radiographic tumor response occurs in tumors located in posterior versus anterior liver segments following radioembolization with yttrium-90 glass microspheres. One hundred thirty-seven patients with chemorefractory liver metastases of various primaries were treated with yttrium-90 glass microspheres. Of these, a subset analysis was performed on 89 patients who underwent 101 whole-right-lobe infusions to liver segments V, VI, VII, and VIII. Pre- and posttreatment imaging included either triphasic contrast material-enhanced CT or gadolinium-enhanced MRI. Responses to treatment were compared in anterior versus posterior right lobe lesions using both RECIST and WHO criteria. Statistical comparative studies were conducted in 42 patients with both anterior and posterior segment lesions using the paired-sample t-test. Pearson correlation was used to determine the relationship between pretreatment tumor size and posttreatment tumor response. Median administered activity, delivered radiation dose, and treatment volume were 2.3 GBq, 118.2 Gy, and 1,072 cm(3), respectively. Differences between the pretreatment tumor size of anterior and posterior liver segments were not statistically significant (p = 0.7981). Differences in tumor response between anterior and posterior liver segments were not statistically significant using WHO criteria (p = 0.8557). A statistically significant correlation did not exist between pretreatment tumor size and posttreatment tumor response (r = 0.0554, p = 0.4434). On imaging follow-up using WHO criteria, for anterior and posterior regions of the liver, (1) response rates were 50% (PR = 50%) and 45% (CR = 9%, PR = 36%), and (2) mean changes in tumor size were -41% and -40%. In conclusion, this study did not find evidence of preferential radiographic tumor response in posterior versus anterior liver segments treated with yttrium-90 glass microspheres.

Study of the photovoltaic effect in thin film barium titanate

NASA Technical Reports Server (NTRS)

Grannemann, W. W.; Dharmadhikari, V. S.

1983-01-01

The feasibility of making non-volatile digital memory devices of barium titanate, BaTiO3, that are integrated onto a silicon substrate with the required ferroelectric film produced by processing, compatible with silicon technology was examined.

Scanning-SQUID investigation of spin-orbit torque acting on yttrium iron garnet devices

NASA Astrophysics Data System (ADS)

Rosenberg, Aaron J.; Jermain, Colin L.; Aradhya, Sriharsha V.; Brangham, Jack T.; Nowack, Katja C.; Kirtley, John R.; Yang, Fengyuan; Ralph, Daniel C.; Moler, Kathryn A.

Successful manipulation of electrically insulating magnets, such as yttrium iron garnet, by by current-driven spin-orbit torques could provide a highly efficient platform for spintronic memory. Compared to devices fabricated using magnetic metals, magnetic insulators have the advantage of the ultra-low magnetic damping and the elimination of shunting currents in the magnet that reduce the torque efficiency. Here, we apply current in the spin Hall metal β-Ta to manipulate the magnetic orientation of micron-sized, electrically-insulating yttrium iron garnet devices. We do not observe spin-torque switching even for applied currents well above the critical current expected in a macrospin switching model. This suggests either inefficient transfer of spin torque at our Ta/YIG interface or a breakdown of the macrospin approximation. This work is supported by FAME, one of six centers of STARnet sponsored by MARCO and DARPA. The SQUID microscope and sensors were developed with support from the NSF-sponsored Center NSF-NSEC 0830228, and from NSF IMR-MIP 0957616.

Effect of lattice strain on structural and magnetic properties of Ca substituted barium hexaferrite

NASA Astrophysics Data System (ADS)

Kumar, Sunil; Supriya, Sweety; Pandey, Rabichandra; Pradhan, Lagen Kumar; Singh, Rakesh Kumar; Kar, Manoranjan

2018-07-01

The calcium (Ca2+) substituted M-type barium hexaferrite (Ba1-xCaxFe12O19) for Ca2+ (x = 0.00, 0.025, 0.050, 0.075, 0.100, 0.150, and 0.200) have been synthesized by the citrate sol-gel method. The X-ray diffraction (XRD) patterns with Rietveld refinement reveal the formation of hexagonal crystal structure with P63/mmc space group. The lattice parameters a = b and c decrease, whereas lattice strain found to increase with the increase in Ca concentration in the samples. The analysis of Raman spectra well supports the XRD patterns analysis. The average particle size is obtained from the FE-SEM (Field Emission Scanning Electron Microscopy) micrographs and these are similar to that of crystallite size obtained from the XRD pattern analysis. The saturation magnetization and magnetocrystalline anisotropy have been obtained by employing the "Law of Approach (LA) to Saturation magnetization" technique at room temperature. The saturation magnetization and magnetocrystalline anisotropy constant are maximum for 5% Ca substitution in barium hexaferrite. It could be due to lattice strain mediated magnetism. However, these magnetic properties decrease for more than the 5% Ca substitution in barium hexaferrite. It could be due to decrease of magnetic exchange interaction (Fe-O-Fe) in the sample. A correlation between magnetic interaction and lattice strain has been observed in Ca2+ substituted M-type barium hexaferrite.

Revealing the Coulomb interaction strength in a cuprate superconductor

DOE PAGES

Yang, S. -L.; Sobota, J. A.; He, Y.; ...

2017-12-08

Here, we study optimally doped Bi 2 Sr 2 Ca 0.92 Y 0.08 Cu 2 O 8 + δ (Bi2212) using angle-resolved two-photon photoemission spectroscopy. Three spectral features are resolved near 1.5, 2.7, and 3.6 eV above the Fermi level. By tuning the photon energy, we determine that the 2.7-eV feature arises predominantly from unoccupied states. The 1.5- and 3.6-eV features reflect unoccupied states whose spectral intensities are strongly modulated by the corresponding occupied states. These unoccupied states are thus consistent with the prediction from a cluster perturbation theory based on the single-band Hubbard model. Through this comparison, amore » Coulomb interaction strength U of 2.7 eV is extracted. Our study complements equilibrium photoemission spectroscopy and provides a direct spectroscopic measurement of the unoccupied states in cuprates. The determined Coulomb U indicates that the charge-transfer gap of optimally doped Bi2212 is 1.1 eV.« less

Radiosynovectomy in haemophilic synovitis of elbows and ankles: Is the effectiveness of yttrium-90 and rhenium-186 different?

PubMed

Rodriguez-Merchan, E C; De La Corte-Rodriguez, H

2016-04-01

Radiosynovectomy (RS) reduces the number of haemarthroses and the synovial size in chronic haemophilic synovitis. The purpose of this study was to quantitatively compare the effectiveness of two types of RS (yttrium-90 vs. rhenium-186) in terms of the objective improvement of haemarthroses and synovial size. Seventy RSs were performed in 70 joints (44 elbows, 26 ankles) of 70 haemophiliacs diagnosed with chronic synovitis. Yttrium-90 was used in 21 joints and rhenium-186 was used in 49 joints. The mean patient age was 20.61 years. RS resulted in significant improvement in the three variables studied (six months before RS vs. six months after RS), namely in the number of episodes of haemarthrosis (67.8% improvement); the size of the synovium as measured by means of a clinical scale (43.8% improvement) and imaging techniques in millimetres (26.7% improvement). We did not find significant statistical differences between yttrium-90 and rhenium-186 regarding their efficacy. No correlation was found between the results and other variables: age, joint (ankle or elbow), presence or absence of radiological involvement, type of haemophilia (A or B), grade of haemophilia (mild, moderate or severe), previous haematological treatment (on demand or prophylaxis), and the presence or absence of inhibitor Yttrium-90 RS and rhenium-186 RS were equally effective in reducing the number of haemarthroses and the size of the synovium in ankles and elbows in the short-term (6 months). No correlation was found between the results and other patients' characteristics. Copyright © 2016 Elsevier Ltd. All rights reserved.

Neodymium:yttrium-aluminum-garnet laser fusion of endarterectomy flaps.

PubMed

Humphrey, P W; Slocum, M M; Loy, T S; Silver, D

1995-07-01

This study evaluated the efficacy of neodymium:yttrium-aluminum-garnet laser welding of flaps in canine arteries and in securing the distal flap during human carotid endarterectomy. Endarterectomy flaps were created in both common carotid and both common femoral arteries in 12 dogs. The flaps were repaired with either the neodymium:yttrium-aluminum-garnet laser or with 6-0 polypropylene sutures. The arteries were removed after duplex scanning at either 7 or 28 days. Eighteen high carotid endarterectomy flaps in 16 patients have been subsequently secured with the laser welding technique. Laser repairs (125 +/- 19 joule) of the canine arteries were completed more quickly than suture repairs (mean 25 seconds vs 135 seconds, respectively; p < 0.04). Duplex ultrasonography revealed no discernable differences between the two groups of arteries. Arteries studied at 7 days revealed three microscopic flaps (two suture, one laser), more subintimal fibroblastic proliferation in suture than laser-repaired carotid arteries (3: 1, p = 0.0530), and similar amounts of inflammation in suture- and laser-repaired arteries. Arteries studied at 28 days revealed one microscopic intimal flap (suture-repaired); equal fibroblastic and inflammatory responses in suture- and laser-repaired vessels; and no evidence of laser thermal injury. Eighteen carotid endarterectomy flaps have been successfully fused with no immediate or long-term complications in 16 patients (follow-up of 0 to 24 months). Laser fusion appears to be a safe and effective method for securing distal carotid endarterectomy flaps.

Strontium and barium isotopes in presolar silicon carbide grains measured with CHILI—two types of X grains

DOE PAGES

Stephan, Thomas; Trappitsch, Reto; Davis, Andrew M.; ...

2017-05-10

Here, we used CHILI, the Chicago Instrument for Laser Ionization, a new resonance ionization mass spectrometer developed for isotopic analysis of small samples, to analyze strontium, zirconium, and barium isotopes in 22 presolar silicon carbide grains. Twenty of the grains showed detectable strontium and barium, but none of the grains had enough zirconium to be detected with CHILI. Nine grains were excluded from further consideration since they showed very little signals (<1000 counts) for strontium as well as for barium. Among the 11 remaining grains, we found three X grains. The discovery of three supernova grains among only 22 grainsmore » was fortuitous, because only ~1% of presolar silicon carbide grains are type X, but was confirmed by silicon isotopic measurements of grain residues with NanoSIMS. And while one of the X grains showed strontium and barium isotope patterns expected for supernova grains, the two other supernova grains have 87Sr/86Sr < 0.5, values never observed in any natural sample before. From their silicon isotope ratios, the latter two grains can be classified as X2 grains, while the former grain belongs to the more common X1 group. The differences of these grains in strontium and barium isotopic composition constrain their individual formation conditions in Type II supernovae.« less

Strontium and barium isotopes in presolar silicon carbide grains measured with CHILI—two types of X grains

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

Stephan, Thomas; Trappitsch, Reto; Davis, Andrew M.

Here, we used CHILI, the Chicago Instrument for Laser Ionization, a new resonance ionization mass spectrometer developed for isotopic analysis of small samples, to analyze strontium, zirconium, and barium isotopes in 22 presolar silicon carbide grains. Twenty of the grains showed detectable strontium and barium, but none of the grains had enough zirconium to be detected with CHILI. Nine grains were excluded from further consideration since they showed very little signals (<1000 counts) for strontium as well as for barium. Among the 11 remaining grains, we found three X grains. The discovery of three supernova grains among only 22 grainsmore » was fortuitous, because only ~1% of presolar silicon carbide grains are type X, but was confirmed by silicon isotopic measurements of grain residues with NanoSIMS. And while one of the X grains showed strontium and barium isotope patterns expected for supernova grains, the two other supernova grains have 87Sr/86Sr < 0.5, values never observed in any natural sample before. From their silicon isotope ratios, the latter two grains can be classified as X2 grains, while the former grain belongs to the more common X1 group. The differences of these grains in strontium and barium isotopic composition constrain their individual formation conditions in Type II supernovae.« less

JPRS Report Science & Technology Europe & Latin America.

DTIC Science & Technology

1997-09-11

mixture of barium, yttrium, copper, and oxygen) was that of the Institute for Research in Non -Traditional Materials of the CNR [National Research...the necessary equipment for this kind of experimental work. The problem now is to coordinate all these branches of research which were begun...Nuclear Physics, the CNR [National Research Council] Institute for Non -Traditional Materials Technology, the physics departments of Naples and Salerno

Microcapsules with Intrinsic Barium Radiopacity for Immunoprotection and X-ray/CT imaging of Pancreatic Islet Cells

PubMed Central

Arifin, D.R.; Manek, S.; Call, E.; Arepally, A.; Bulte, J.W.M.

2012-01-01

Microencapsulation is a commonly used technique for immunoprotection of engrafted therapeutic cells. We investigated a library of capsule formulations to determine the most optimal formulation for pancreatic beta islet cell transplantation, using barium as the gelating ion and clinical-grade protamine sulfate (PS) as a new cationic capsule cross-linker. Barium-gelated alginate/PS/alginate microcapsules (APSA, diameter = 444±21 μm) proved to be mechanically stronger and supported a higher cell viability as compared to conventional alginate/poly-L-lysine/alginate (APLLA) capsules. Human pancreatic islets encapsulated inside APSA capsules, gelated with 20 mM barium as optimal concentration, exhibited a sustained morphological integrity, viability, and functionality for at least 3–4 weeks in vitro, with secreted human C-peptide levels of 0.2–160 pg/ml/islet. Unlike APLLA capsules that are gelled with calcium, barium-APSA capsules are intrinsically radiopaque and, when engrafted into mice, could be readily imaged in vivo with micro-computed tomography (CT). Without the need of adding contrast agents, these capsules offer a clinically applicable alternative for simultaneous immunoprotection and real-time, non-invasive X-ray/CT monitoring of engrafted cells during and after in vivo administration. PMID:22444642

Antibacterial and antibiofilm properties of yttrium fluoride nanoparticles

PubMed Central

Lellouche, Jonathan; Friedman, Alexandra; Gedanken, Aharon; Banin, Ehud

2012-01-01

Antibiotic resistance has prompted the search for new agents that can inhibit bacterial growth. Moreover, colonization of abiotic surfaces by microorganisms and the formation of biofilms is a major cause of infections associated with medical implants, resulting in prolonged hospitalization periods and patient mortality. In this study we describe a water-based synthesis of yttrium fluoride (YF3) nanoparticles (NPs) using sonochemistry. The sonochemical irradiation of an aqueous solution of yttrium (III) acetate tetrahydrate [Y(Ac)3 · (H2O)4], containing acidic HF as the fluorine ion source, yielded nanocrystalline needle-shaped YF3 particles. The obtained NPs were characterized by scanning electron microscopy and X-ray elemental analysis. NP crystallinity was confirmed by electron and powder X-ray diffractions. YF3 NPs showed antibacterial properties against two common bacterial pathogens (Escherichia coli and Staphylococcus aureus) at a μg/mL range. We were also able to demonstrate that antimicrobial activity was dependent on NP size. In addition, catheters were surface modified with YF3 NPs using a one-step synthesis and coating process. The coating procedure yielded a homogeneous YF3 NP layer on the catheter, as analyzed by scanning electron microscopy and energy dispersive spectroscopy. These YF3 NP-modified catheters were investigated for their ability to restrict bacterial biofilm formation. The YF3 NP-coated catheters were able to significantly reduce bacterial colonization compared to the uncoated surface. Taken together, our results highlight the potential to further develop the concept of utilizing these metal fluoride NPs as novel antimicrobial and antibiofilm agents, taking advantage of their low solubility and providing extended protection. PMID:23152681

Hourglass Dispersion and Resonance of Magnetic Excitations in the Superconducting State of the Single-Layer Cuprate HgBa 2 CuO 4 + δ Near Optimal Doping

DOE PAGES

Chan, M. K.; Tang, Y.; Dorow, C. J.; ...

2016-12-29

Here, we use neutron scattering to study magnetic excitations near the antiferromagnetic wave vector in the underdoped single-layer cuprate HgBa 2 CuO 4 + δ (superconducting transition temperature T c ≈ 88 K , pseudogap temperature T* ≈ 220 K ). The response is distinctly enhanced below T* and exhibits a Y -shaped dispersion in the pseudogap state, whereas the superconducting state features an X -shaped (hourglass) dispersion and a further resonancelike enhancement. We also observe a large spin gap of about 40 meV in both states. This phenomenology is reminiscent of that exhibited by bilayer cuprates. The resonance spectralmore » weight, irrespective of doping and compound, scales linearly with the putative binding energy of a spin exciton described by an itinerant-spin formalism.« less

Elevated Z line: a new sign of Barrett's esophagus on double-contrast barium esophagograms.

PubMed

Levine, Marc S; Ahmad, Nuzhat A; Rubesin, Stephen E

2015-01-01

We describe an elevated Z line as a new radiographic sign of Barrett's esophagus characterized by a transversely oriented, zigzagging, barium-etched line extending completely across the circumference of the midesophagus. An elevated Z line is rarely seen in other patients, so this finding should be highly suggestive of Barrett's esophagus on double-contrast barium esophagograms. If the patient is a potential candidate for surveillance, endoscopy and biopsy should be performed to confirm the presence of Barrett's esophagus. Copyright © 2015 Elsevier Inc. All rights reserved.

Two-Dimensional Superconductivity in the Cuprates Revealed by Atomic-Layer-by- Layer Molecular Beam Epitaxy

DOE PAGES

A. T. Bollinger; Bozovic, I.

2016-08-12

Various electronic phases displayed by cuprates that exhibit high temperature superconductivity continue to attract much interest. We provide a short review of several experiments that we have performed aimed at investigating the superconducting state in these compounds. Measurements on single-phase films, bilayers, and superlattices all point to the conclusion that the high-temperature superconductivity in these materials is an essentially quasi-two dimensional phenomenon. With proper control over the film growth, high-temperature superconductivity can exist in a single copper oxide plane with the critical temperatures as high as that achieved in the bulk samples.

Quasiparticle Coherence, Collective Modes, and Competing Order in Cuprate Superconductors

NASA Astrophysics Data System (ADS)

Hinton, James Patrick

In recent years, the study of cuprate superconductors has been dominated by the investigation of normal state properties. Of particular interest is the nature of interactions between superconductivity and other incipient orders which emerge above the superconducting transition temperature, Tc. The discovery of charge density wave (CDW) correlations in YBa2Cu3O6+x (YBCO) and HgBa2CuO 4+d (Hg-1201) has established that some form of charge order is ubiquitous in the cuprates. In this work, we explore the non-equilibrium dynamics of systems which sit near the boundary between superconductivity and competing orders. Ultrafast pump-probe spectroscopy is ideally suited to the study of competing order. Exciting the sample with an optical pulse perturbs the system from equilibrium, altering the balance between the co-existing orders. The return to equilibrium is then monitored by a time-delayed probe pulse, revealing multiple decay processes as well as collective excitations. We first apply this technique to Hg-1201, conducting a detailed study of the phase diagram. At temperatures near Tc, the pump pulse induces a non-equilibrium quasiparticle population. At Tc we observe a doping-dependent peak in the relaxation time of these quasiparticles which we associate with a divergence in the coherence time of the fluctuating CDW. Using heterodyne probing in the transient grating geometry, we are able to disentangle the transient reflectivity components associated with superconductivity and the pseudogap, domonstrating competition across the phase diagram. We also discuss the observation of a sharp transition in the nature of the pseudogap signal at ˜ 11% doping. In YBCO, we explore the temperature and doping dependence of coherent oscillations excited by the pump pulse. We associate these oscillations with the excitation of the CDW amplitude mode, and model their temperature dependence within the framework of a Landau model of competing orders. We conclude with an investigation

Self-assembly of a tetrahedral 58-nuclear barium vanadium oxide cluster.

PubMed

Kastner, Katharina; Puscher, Bianka; Streb, Carsten

2013-01-07

We report the synthesis and characterization of a molecular barium vanadium oxide cluster featuring high nuclearity and high symmetry. The tetrameric, 2.3 nm cluster H(5)[Ba(10)(NMP)(14)(H(2)O)(8)[V(12)O(33)](4)Br] is based on a bromide-centred, octahedral barium scaffold which is capped by four previously unknown [V(12)O(33)](6-) clusters in a tetrahedral fashion. The compound represents the largest polyoxovanadate-based heterometallic cluster known to date. The cluster is formed in organic solution and it is suggested that the bulky N-methyl-2-pyrrolidone (NMP) solvent ligands allow the isolation of this giant molecule and prevent further condensation to a solid-state metal oxide. The cluster is fully characterized using single-crystal XRD, elemental analysis, ESI mass spectrometry and other spectroscopic techniques.

Electrical and thermal properties of Ca and Ni doped barium ferrite

NASA Astrophysics Data System (ADS)

Agrawal, Shraddha; Parveen, Azra; Azam, Ameer

2018-05-01

Ca and Ni doped M type Barium ferrite of the composition ((Ba0.9Ca0.1) (Fe0.8 Ni0.2)12O19) were prepared by the traditional sol gel auto combustion method using citric acid as a fuel. Microstructural analyses were carried out with the help of XRD and SEM. XRD analysis is the evidence of nanometer regime along with crystalline planes of hexagonal structure. It also confirms the hexagonal structure of barium ferrite even with the doping of Ca and Ni. SEM analysis is the signature of the spherical shape and surface morphology of agglomerated form of nano-powders of doped samples. The thermal properties of samples were carried out with the help of TGA. That shows the variation of weight loss of the prepared sample with the temperature.

Barium as a potential indicator of phosphorus in agricultural runoff.

PubMed

Ahlgren, Joakim; Djodjic, Faruk; Wallin, Mats

2012-01-01

In many catchments, anthropogenic input of contaminants, and in particular phosphorus (P), into surface water is a mixture of agricultural and sewage runoff. Knowledge about the relative contribution from each of these sources is vital for mitigation of major environmental problems such as eutrophication. In this study, we investigated whether the distribution of trace elements in surface waters can be used to trace the contamination source. Water from three groups of streams was investigated: streams influenced only by agricultural runoff, streams influenced mainly by sewage runoff, and reference streams. Samples were collected at different flow regimes and times of year and analyzed for 62 elements using ICP-MS. Our results show that there are significant differences between the anthropogenic sources affecting the streams in terms of total element composition and individual elements, indicating that the method has the potential to trace anthropogenic impact on surface waters. The elements that show significant differences between sources are strontium (p < 0.001), calcium (p < 0.004), potassium (p < 0.001), magnesium (p < 0.001), boron (p < 0.001), rhodium (p = 0.001), and barium (p < 0.001). According to this study, barium shows the greatest potential as a tracer for an individual source of anthropogenic input to surface waters. We observed a strong relationship between barium and total P in the investigated samples (R(2) = 0.78), which could potentially be used to apportion anthropogenic sources of P and thereby facilitate targeting of mitigation practices. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Bioavailability of barium to plants and invertebrates in soils contaminated by barite.

PubMed

Lamb, Dane T; Matanitobua, Vitukawalu P; Palanisami, Thavamani; Megharaj, Mallavarapu; Naidu, Ravi

2013-05-07

Barium (Ba) is a nonessential element to terrestrial organisms and is known to be toxic at elevated concentrations. In this study, the bioavailability and toxicity of Ba in barite (BaSO4) contaminated soils was studied using standard test organisms (Lactuca sativa L. "Great Lakes", Eisenia fetida). Contamination resulted from barite mining activities. Barium concentrations in contaminated soils determined by X-ray fluorescence were in the range 0.13-29.2%. Barite contaminated soils were shown to negatively impact both E. fetida and L. sativa relative to control soil. For E. fetida, pore-water concentrations and acid extractable Ba were linearly related to % body weight loss. In L. sativa, pore-water Ba and exchangeable Ba were both strongly related to shoot Ba and shoot biomass production. A negative linear relationship was observed between shoot Ba content and shoot weight (P < 0.0004, R(2) = 0.39), indicating that Ba accumulation is likely to have induced phytotoxicity. Plant weights were correlated to % weight loss in earthworm (r = -0.568, P = 0.028). Barium concentrations in pore-water were lower than predicted from barite solubility estimates but strongly related to exchangeable Ba, indicating an influence of ion exchange on Ba solubility and toxicity to E. fetida and L. sativa.

Applicaton of the Calculating Formula for Mean Neutron Exposure on Barium stars

NASA Astrophysics Data System (ADS)

Zhang, F. H.; Zhang, L.; Cui, W. Y.; Zhang, B.

2017-11-01

Latest studies have shown that, in the s-process nucleosynthesis model for the low-mass asymptotic giant branch (AGB) star with (13C) pocket radiative burning during the interpulse period, the distribution of neutron exposures in the nucleosynthesis region can be regarded as an exponential function, and the relation between the mean neutron exposure (τ0) and the model parameters is (τ0} = - Δ τ/ln [q/(1 - r + q)]), in which (Δ τ) is the exposure value of each neutron irradiation, (r) is the overlap factor, and (q) is the mass ratio of the (13C) shell to the He intershell. In this paper the formula is applied to 26 samples of barium stars to test its reliability, and furthermore the neutron exposure nature in the AGB companion stars of 26 barium stars are analyzed. The results show that, the formula is reliable; in the AGB companion stars of 26 barium stars, at least 8 stars definitely have and 12 stars are highly likely to have exponential distribution of neutron exposures, while 4 stars tend to experience single neutron exposure; most of the AGB companion stars may have experienced fewer times of neutron irradiations before the element abundance distribution of the s-process comes to asymptotic condition.

Electronic polymers and soft-matter-like broken symmetries in underdoped cuprates.

PubMed

Capati, M; Caprara, S; Di Castro, C; Grilli, M; Seibold, G; Lorenzana, J

2015-07-06

Empirical evidence in heavy fermion, pnictide and other systems suggests that unconventional superconductivity appears associated to some form of real-space electronic order. For the cuprates, despite several proposals, the emergence of order in the phase diagram between the commensurate antiferromagnetic state and the superconducting state is not well understood. Here we show that in this regime doped holes assemble in 'electronic polymers'. Within a Monte Carlo study, we find that in clean systems by lowering the temperature the polymer melt condenses first in a smectic state and then in a Wigner crystal both with the addition of inversion symmetry breaking. Disorder blurs the positional order leaving a robust inversion symmetry breaking and a nematic order, accompanied by vector chiral spin order and with the persistence of a thermodynamic transition. Such electronic phases, whose properties are reminiscent of soft-matter physics, produce charge and spin responses in good accord with experiments.

Quantum critical point underlying the pseudogap state in underdoped cuprate superconductors

NASA Astrophysics Data System (ADS)

Pepin, Catherine

2014-03-01

Cuprate superconductors rank among the most complex materials that are known in the universe. Faced with this complexity, scientists have adopted two types of approaches. In a bottom up approach, one considers that strong correlations occur at a high energy scale of roughly 1 eV upon very strong Coulomb interactions. In the top down approach one considers that one universal singularity at very low temperatures is responsible for complexity of the phase diagram. In this talk we will argue that the strong quantum fluctuations experienced at the proximity to a anti-ferromagnetic Quantum Critical Point (QCP) is responsible for a cascade of phase transitions in the charge and superconducting channels. We will discuss in this context the emergence of the pseudo-gap and charge order modulations. Symmetries and relations to experimental observations will be addressed. Work done in collaboration with K.B. Efetov (Bochum) and H. Meier (Yale).

Barium isotope fractionation during experimental formation of the double carbonate BaMn[CO3](2) at ambient temperature.

PubMed

Böttcher, Michael E; Geprägs, Patrizia; Neubert, Nadja; von Allmen, Katja; Pretet, Chloé; Samankassou, Elias; Nägler, Thomas F

2012-09-01

In this study, we present the first experimental results for stable barium (Ba) isotope ((137)Ba/(134)Ba) fractionation during low-temperature formation of the anhydrous double carbonate BaMn[CO(3)](2). This investigation is part of an ongoing work on Ba fractionation in the natural barium cycle. Precipitation at a temperature of 21±1°C leads to an enrichment of the lighter Ba isotope described by an enrichment factor of-0.11±0.06‰ in the double carbonate than in an aqueous barium-manganese(II) chloride/sodium bicarbonate solution, which is within the range of previous reports for synthetic pure BaCO (3) (witherite) formation.

Maintaining High Strength in Mg-LPSO Alloys with Low Yttrium Content Using Severe Plastic Deformation.

PubMed

Garces, Gerardo; Cabeza, Sandra; Barea, Rafael; Pérez, Pablo; Adeva, Paloma

2018-05-05

Alternative processing routes such as powder metallurgy, the extrusion of recycled chips, or equal channel angular pressing (ECAP) have been considered for effective methods of maintaining the high mechanical strength of Mg-Y-Zn alloys containing long-period stacking ordered structures with respect to the alloy processed by the conventional extrusion of as-cast ingots with the advantage of minimizing the yttrium content. A yield stress similar to that found for extruded Mg 97 Y₂Zn₁ alloy can be attained with only half of the usual yttrium and zinc additions thanks to the grain refinement induced by ECAP processing. The properties of Mg 98.5 Y₁Zn 0.5 subjected to ECAP are maintained up to 200 °C, but superplastic behavior is found above this temperature when the alloy is processed through a powder metallurgy route.

Dynamics of a barium release in the magnetospheric tail

NASA Technical Reports Server (NTRS)

Mende, S. B.; Swenson, G. R.; Geller, S. P.; Doolittle, J. H.; Haerendel, G.

1989-01-01

The late time behavior of the May 13, 1985 magnetotail barium cloud is examined. The bulk dynamics of the cloud are studied based on triangulated data and data from Fabry-Perot Doppler velocity measurements. The changes in cloud morphology in relation to the in situ measurements made by the Ion Release Module satellite are discussed.

Comparison of Barium and Arsenic Concentrations in Well Drinking Water and in Human Body Samples and a Novel Remediation System for These Elements in Well Drinking Water.

PubMed

Kato, Masashi; Kumasaka, Mayuko Y; Ohnuma, Shoko; Furuta, Akio; Kato, Yoko; Shekhar, Hossain U; Kojima, Michiyo; Koike, Yasuko; Dinh Thang, Nguyen; Ohgami, Nobutaka; Ly, Thuy Bich; Jia, Xiaofang; Yetti, Husna; Naito, Hisao; Ichihara, Gaku; Yajima, Ichiro

2013-01-01

Health risk for well drinking water is a worldwide problem. Our recent studies showed increased toxicity by exposure to barium alone (≤700 µg/L) and coexposure to barium (137 µg/L) and arsenic (225 µg/L). The present edition of WHO health-based guidelines for drinking water revised in 2011 has maintained the values of arsenic (10 µg/L) and barium (700 µg/L), but not elements such as manganese, iron and zinc. Nevertheless, there have been very few studies on barium in drinking water and human samples. This study showed significant correlations between levels of arsenic and barium, but not its homologous elements (magnesium, calcium and strontium), in urine, toenail and hair samples obtained from residents of Jessore, Bangladesh. Significant correlation between levels of arsenic and barium in well drinking water and levels in human urine, toenail and hair samples were also observed. Based on these results, a high-performance and low-cost adsorbent composed of a hydrotalcite-like compound for barium and arsenic was developed. The adsorbent reduced levels of barium and arsenic from well water in Bangladesh and Vietnam to <7 µg/L within 1 min. Thus, we have showed levels of arsenic and barium in humans and propose a novel remediation system.

Comparison of Barium and Arsenic Concentrations in Well Drinking Water and in Human Body Samples and a Novel Remediation System for These Elements in Well Drinking Water

PubMed Central

Kato, Masashi; Kumasaka, Mayuko Y.; Ohnuma, Shoko; Furuta, Akio; Kato, Yoko; Shekhar, Hossain U.; Kojima, Michiyo; Koike, Yasuko; Dinh Thang, Nguyen; Ohgami, Nobutaka; Ly, Thuy Bich; Jia, Xiaofang; Yetti, Husna; Naito, Hisao; Ichihara, Gaku; Yajima, Ichiro

2013-01-01

Health risk for well drinking water is a worldwide problem. Our recent studies showed increased toxicity by exposure to barium alone (≤700 µg/L) and coexposure to barium (137 µg/L) and arsenic (225 µg/L). The present edition of WHO health-based guidelines for drinking water revised in 2011 has maintained the values of arsenic (10 µg/L) and barium (700 µg/L), but not elements such as manganese, iron and zinc. Nevertheless, there have been very few studies on barium in drinking water and human samples. This study showed significant correlations between levels of arsenic and barium, but not its homologous elements (magnesium, calcium and strontium), in urine, toenail and hair samples obtained from residents of Jessore, Bangladesh. Significant correlation between levels of arsenic and barium in well drinking water and levels in human urine, toenail and hair samples were also observed. Based on these results, a high-performance and low-cost adsorbent composed of a hydrotalcite-like compound for barium and arsenic was developed. The adsorbent reduced levels of barium and arsenic from well water in Bangladesh and Vietnam to <7 µg/L within 1 min. Thus, we have showed levels of arsenic and barium in humans and propose a novel remediation system. PMID:23805262

Special features of changes in the structure and mechanical properties of oxygen-free pure and yttrium-alloyed copper after vacuum induction remelting

NASA Astrophysics Data System (ADS)

Kamyshanchenko, N. V.; Galtsev, A. V.; Durykhin, M. I.; Neklyudov, I. M.; Borts, B. V.; Shevchenko, S. V.

2011-03-01

Properties of oxygen-free copper with a microadditive of yttrium and without it are studied after vacuum induction remelting. The ingots are subjected to intense hot pressing and subsequent rolling to various degrees of reduction. The effects of the annealing temperature on the structure and of the anisotropy of the structure on the strength properties of the copper are determined. The properties of copper with an additive of yttrium and without it are compared.

[Optics heterodyne detection of the autoionization state of barium].

PubMed

Sun, Jiang; Su, Hong-xin; Wang, Yan-bang; Guo, Qing-lin; Zuo, Zhan-chun; Fu, Pan-ming

2008-06-01

The autoionization state of barium was observed by optics heterodyne between three-photon resonant nondegenerated six-wave mixing (NSWM) and two-photon resonant nondegenerated four-wave mixing (NFWM). In this way, optics heterodyne spectrum of 6p(3/2) 19d autoionization state of barium was measured. The suppression and enhancement of the NFWM signal was observed which was caused by the quantum interference between NFWM and NSWM. Our method is a pure nonlinear optic technique. It has the advantages of excellent spatial signal resolution and simple optical alignment. Here two-photon resonant NFWM is used as local oscillation, while three-photon resonant NSWM signal is used as signal beam. Detection of autoionization states of Ba was achieved by changing the frequency of signal beam. The phase matching condition of this technique is not so stringent and can be achieved over a very wide frequency range, which is very difficult in the general six-wave mixing. Furthermore, the signal is coherent light. Optics heterodyne spectrum is a Doppler-free spectroscopy when the incident lasers have narrow bandwidths.

Magneto-optical properties of cerium substituted yttrium iron garnet films with reduced thermal budget for monolithic photonic integrated circuits.

PubMed

Goto, Taichi; Onbaşlı, Mehmet C; Ross, C A

2012-12-17

Thin films of polycrystalline cerium substituted yttrium iron garnet (CeYIG) were grown on an yttrium iron garnet (YIG) seed layer on Si and Si-on-insulator substrates by pulsed laser deposition, and their optical and magneto-optical properties in the near-IR region were measured. A YIG seed layer of ~30 nm thick processed by rapid thermal anneal at 800°C provided a virtual substrate to promote crystallization of the CeYIG. The effect of the thermal budget of the YIG/CeYIG growth process on the film structure, magnetic and magnetooptical properties was determined.

Resonant inelastic X-ray scattering study of spin-wave excitations in the cuprate parent compound Ca 2CuO 2Cl 2

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

Lebert, B. W.; Dean, M.; Nicolaou, A.

By means of resonant inelastic x-ray scattering at the Cu L 3 edge, we measured the spin wave dispersion along <100> and <110> in the undoped cuprate Ca 2CuO 2Cl 2. The data yields a reliable estimate of the superexchange parameter J = 135 ± 4 meV using a classical spin-1/2 2D Heisenberg model with nearest-neighbor interactions and including quantum fluctuations. Including further exchange interactions increases the estimate to J = 141 meV. The 40 meV dispersion between the magnetic Brillouin zone boundary points (1/2, 0) and (1/4, 1/4) indicates that next-nearest neighbor interactions in this compound are intermediate betweenmore » the values found in La 2CuO 4 and Sr 2CuO 2Cl 2. Here by owing to the low- Z elements composing Ca 2CuOCl 2, the present results may enable a reliable comparison with the predictions of quantum many-body calculations, which would improve our understanding of the role of magnetic excitations and of electronic correlations in cuprates.« less

Resonant inelastic X-ray scattering study of spin-wave excitations in the cuprate parent compound Ca 2CuO 2Cl 2

DOE PAGES

Lebert, B. W.; Dean, M.; Nicolaou, A.; ...

2017-04-07

By means of resonant inelastic x-ray scattering at the Cu L 3 edge, we measured the spin wave dispersion along <100> and <110> in the undoped cuprate Ca 2CuO 2Cl 2. The data yields a reliable estimate of the superexchange parameter J = 135 ± 4 meV using a classical spin-1/2 2D Heisenberg model with nearest-neighbor interactions and including quantum fluctuations. Including further exchange interactions increases the estimate to J = 141 meV. The 40 meV dispersion between the magnetic Brillouin zone boundary points (1/2, 0) and (1/4, 1/4) indicates that next-nearest neighbor interactions in this compound are intermediate betweenmore » the values found in La 2CuO 4 and Sr 2CuO 2Cl 2. Here by owing to the low- Z elements composing Ca 2CuOCl 2, the present results may enable a reliable comparison with the predictions of quantum many-body calculations, which would improve our understanding of the role of magnetic excitations and of electronic correlations in cuprates.« less

Synthesis of nanostructured barium phosphate and its application in micro-computed tomography of mouse brain vessels in ex vivo

NASA Astrophysics Data System (ADS)

Zhu, Bangshang; Yuan, Falei; Yuan, Xiaoya; Bo, Yang; Wang, Yongting; Yang, Guo-Yuan; Drummen, Gregor P. C.; Zhu, Xinyuan

2014-02-01

Micro-computed tomography (micro-CT) is a powerful tool for visualizing the vascular systems of tissues, organs, or entire small animals. Vascular contrast agents play a vital role in micro-CT imaging in order to obtain clear and high-quality images. In this study, a new kind of nanostructured barium phosphate was fabricated and used as a contrast agent for ex vivo micro-CT imaging of blood vessels in the mouse brain. Nanostructured barium phosphate was synthesized through a simple wet precipitation method using Ba(NO3)2, and (NH4)2HPO4 as starting materials. The physiochemical properties of barium phosphate were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and thermal analysis. Furthermore, the impact of the produced nanostructures on cell viability was evaluated via the MTT assay, which generally showed low to moderate cytotoxicity. Finally, the animal test images demonstrated that the use of nanostructured barium phosphate as a contrast agent in Micro-CT imaging produced sharp images with excellent contrast. Both major vessels and the microvasculature were clearly observable in the imaged mouse brain. Overall, the results indicate that nanostructured barium phosphate is a potential and useful vascular contrast agent for micro-CT imaging.

Effects of barium and cadmium on the population development of the marine nematode Rhabditis (Pellioditis) marina.

PubMed

Lira, V F; Santos, G A P; Derycke, S; Larrazabal, M E L; Fonsêca-Genevois, V G; Moens, T

2011-10-01

Offshore oil and gas drilling often involves the use of fluids containing barium and traces of other heavy metals. These may affect the environment, but information on their toxicity to benthic biota remains scant. Here, we present results of a 10-day bioassay with the marine nematode Rhabditis (Pellioditis) marina at different loads of barium (0-10 ,000 ppm nominal concentrations) and cadmium (0-12 ppm) in the range of concentrations reported from drilling-impacted sediments. Barium did not affect the fitness and population development of R. (P.) marina at concentrations up to 300 ppm, but did cause a decrease in population abundance and an increase in development time from concentrations of 400-2000 ppm onwards. Increased mortality occurred at 4800 ppm Ba. For cadmium, LOEC and EC₅₀ values for total population abundance were 2.95 and 8.82 ppm, respectively. Cd concentrations as low as 2.40 to 2.68 caused a decrease in the abundance of adult nematodes, indicating that assays covering more generations would likely demonstrate yet more pronounced population-level effects. Our results indicate that oil and gas drilling activities may potentially have important implications for the meiobenthos through the toxicity of barium and associated metals like cadmium. Copyright © 2011 Elsevier Ltd. All rights reserved.

Microcapsules with intrinsic barium radiopacity for immunoprotection and X-ray/CT imaging of pancreatic islet cells.

PubMed

Arifin, Dian R; Manek, Sameer; Call, Emma; Arepally, Aravind; Bulte, Jeff W M

2012-06-01

Microencapsulation is a commonly used technique for immunoprotection of engrafted therapeutic cells. We investigated a library of capsule formulations to determine the most optimal formulation for pancreatic beta islet cell transplantation, using barium as the gelating ion and clinical-grade protamine sulfate (PS) as a new cationic capsule cross-linker. Barium-gelated alginate/PS/alginate microcapsules (APSA, diameter = 444 ± 21 μm) proved to be mechanically stronger and supported a higher cell viability as compared to conventional alginate/poly-l-lysine/alginate (APLLA) capsules. Human pancreatic islets encapsulated inside APSA capsules, gelated with 20 mm barium as optimal concentration, exhibited a sustained morphological integrity, viability, and functionality for at least 3-4 weeks in vitro, with secreted human C-peptide levels of 0.2-160 pg/ml/islet. Unlike APLLA capsules that are gelled with calcium, barium-APSA capsules are intrinsically radiopaque and, when engrafted into mice, could be readily imaged in vivo with micro-computed tomography (CT). Without the need of adding contrast agents, these capsules offer a clinically applicable alternative for simultaneous immunoprotection and real-time, non-invasive X-ray/CT monitoring of engrafted cells during and after in vivo administration. Copyright © 2012 Elsevier Ltd. All rights reserved.

Diagnostic Validity of High-Density Barium Sulfate in Gastric Cancer Screening: Follow-up of Screenees by Record Linkage with the Osaka Cancer Registry

PubMed Central

Yamamoto, Kenyu; Yamazaki, Hideo; Kuroda, Chikazumi; Kubo, Tsugio; Oshima, Akira; Katsuda, Toshizo; Kuwano, Tadao; Takeda, Yoshihiro

2010-01-01

Background The use of high-density barium sulfate was recommended by the Japan Society of Gastroenterological Cancer Screening (JSGCS) in 2004. We evaluated the diagnostic validity of gastric cancer screening that used high-density barium sulfate. Methods The study subjects were 171 833 residents of Osaka, Japan who underwent gastric cancer screening tests at the Osaka Cancer Prevention and Detection Center during the period from 1 January 2000 through 31 December 2001. Screening was conducted using either high-density barium sulfate (n = 48 336) or moderate-density barium sulfate (n = 123 497). The subjects were followed up and their medical records were linked to those of the Osaka Cancer Registry through 31 December 2002. The results of follow-up during 1 year were defined as the gold standard, and test performance values were calculated. Results The sensitivity and specificity of the screening test using moderate-density barium sulfate were 92.3% and 91.0%, respectively, while the sensitivity and specificity of the high-density barium test were 91.8% and 91.4%, respectively. The results of area under receiver-operating-characteristic (ROC) curve analysis revealed no significant difference between the 2 screening tests. Conclusions Screening tests using high- and moderate-density barium sulfate had similar validity, as determined by sensitivity, specificity, and ROC curve analysis. PMID:20551581

Three-dimensional, two-species magnetohydrodynamic studies of the early time behaviors of the Combined Release and Radiation Effects Satellite G2 barium release

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

Xie, Lianghai, E-mail: xielh@nssc.ac.cn; Li, Lei; Wang, Jingdong

2014-04-15

We present a three-dimensional, two-species (Ba{sup +} and H{sup +}) MHD model to study the early time behaviors of a barium release at about 1 R{sub E} like Combined Release and Radiation Effects Satellite G2, with emphasis placed on the three-dimensional evolution of the barium cloud and its effects on the ambient plasma environment. We find that the perturbations caused by the cloud are the combined results of the initial injection, the radial expansion, and the diamagnetic effect and propagate as fast MHD waves in the magnetosphere. In return, the transverse expansion and the cross-B motion of barium ions aremore » constrained by the magnetic force, which lead to a field-aligned striation of ions and the decoupling of these ions from the neutrals. Our simulation shows the formation and collapse of the diamagnetic cavity in the barium cloud. The estimated time scale for the cavity evolution might be much shorter if photoionization time scale and field aligned expansion of barium ions are considered. In addition, our two species MHD simulation also finds the snowplow effect resulting from the momentum coupling between barium ions and background H{sup +}, which creates density hole and bumps in the background H{sup +} when barium ions expanding along the magnetic field lines.« less

Improvement of kidney redox states contributes to the beneficial effects of dietary pomegranate peel against barium chloride-induced nephrotoxicity in adult rats.

PubMed

Elwej, Awatef; Ghorbel, Imen; Marrekchi, Rim; Boudawara, Ons; Jamoussi, Kamel; Boudawara, Tahia; Zeghal, Najiba; Sefi, Mediha

2016-07-01

Pomegranate (Punica granatum L., Punicaceae) is known to possess enormous antioxidant activity. This study investigates the protective effects of pomegranate peel against barium-mediated renal damage. Rats were exposed during 21 days either to barium (67 ppm), barium + pomegranate peel (5% of diet) or to only pomegranate peel (5% of diet). Exposure rats to barium provoked a significant increase in kidney malondialdehyde (MDA), advanced oxidation protein products (AOPP) and hydrogen peroxide (H2O2) levels. Creatinine, urea and uric acid levels in plasma and urine were also modified. Superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) activities, non protein thiol (NPSH) and reduced glutathione (GSH) levels were decreased. Metallothionein (MT) production was increased and their genes expressions were up-regulated. All these changes were improved by dietary pomegranate peel. Moreover, the distorted histoarchitecture in kidney of barium group was alleviated by pomegranate peel. Our data showed, for the first time, the protective effects of pomegranate peel against barium-induced renal oxidative damage.

Yield and ion distribution for the barium cloud at 31,000 kilometers, September 21, 1971.

NASA Technical Reports Server (NTRS)

Manring, E. R.; Patty, R. R.

1973-01-01

The photon flux density associated with the 4554-A resonance radiation for Ba II was measured at Mount Hopkins, Arizona, and Cerro Morado, Chile, and was determined to be 36,000 photon/sq cm sec outside the atmosphere; this measurement was made when the cloud was optically thin at 120 sec after release. Using this and a photon scattering efficiency of 0.66 photon/ion sec we estimate a 1.7-kg yield of barium ions that are formed from the initially released atomic barium and are thus associated with the main core of the cloud. Photographic and photometric data are combined to obtain preliminary values for the brightness throughout the cloud for two photographs, and isobrightness plots are presented. These plots indicate that the cloud is quite narrow, that a considerable portion of the ionized barium is outside the main core after a few minutes, and that the striations contain only a small fraction of the total material.

Multisite occupation of divalent dopants in barium and strontium titanates

NASA Astrophysics Data System (ADS)

Zulueta, Yohandys A.; Nguyen, Minh Tho

2018-10-01

Based on recent experimental and theoretical proofs of calcium multisite occupation in barium titanate, we investigated a mixed incorporation mechanism for divalent dopants in barium and strontium titanates (BaTiO3 and SrTiO3). Our present theoretical results demonstrated the multisite occupation of divalent dopants in both perovskite structures. We determined the dependences of the solution, binding energies, and final solution energies with respect to the ionic radii of the dopants. Calculated results obtained based on classical simulations showed that the divalent dopants can occupy both A- and Ti- cation sites in ATiO3 perovskite structures. Such a multisite occupation has direct implications for other experimental findings regarding BaTiO3, such as non-stabilization of the tetragonal phase, shifts in the Curie temperature, intensification of the diffuse phase transition, and shifts in the absorption of ultraviolet light to the visible range in photocatalytic applications related to solar cells for producing energy.

Removal of acetaminophen in water by laccase immobilized in barium alginate.

PubMed

Ratanapongleka, Karnika; Punbut, Supot

2018-02-01

This research has focused on the optimization of immobilized laccase condition and utilization in degradation of acetaminophen contaminated in aqueous solution. Laccase from Lentinus polychrous was immobilized in barium alginate. The effects of laccase immobilization such as sodium alginate concentration, barium chloride concentration and gelation time were studied. The optimal conditions for immobilization were sodium alginate 5% (w/v), barium chloride 5% (w/v) and gelation time of 60 min. Immobilized laccase was then used for acetaminophen removal. Acetaminophen was removed quickly in the first 50 min. The degradation rate and percentage of removal increased when the enzyme concentration increased. Immobilized laccase at 0.57 U/g-alginate showed the maximum removal at 94% in 240 min. The removal efficiency decreased with increasing initial acetaminophen concentration. The K m value for immobilized laccase (98.86 µM) was lower than that of free laccase (203.56 µM), indicating that substrate affinity was probably enhanced by immobilization. The immobilized enzyme exhibited high activity and good acetaminophen removal at pH 7 and temperature of 35°C. The activation energies of free and immobilized laccase for degradation of acetaminophen were 8.08 and 17.70 kJ/mol, respectively. It was also found that laccase stability to pH and temperature increased after immobilization. Furthermore, immobilized laccase could be reused for five cycles. The capability of removal and enzyme activity were retained above 70%.

Evolution des quasiparticules nodales du cuprate supraconducteur YBa2Cu3Oy en conductivite thermique

NASA Astrophysics Data System (ADS)

Rene de Cotret, Samuel

Ce memoire presente des mesures de conductivite thermique sur les supraconducteurs YBCO et Tl-2201 afin de statuer sur la presence possible d'un point critique quantique (QCP) dans le diagramme de phase de cuprates. Ce point critique quantique serait a l'origine de la reconstruction de la surface de Fermi, d'un large cylindre de trous en de petites poches de trous et d'electrons. La conductivite thermique dans le regime T → 0 permet d'extraire une quantite purement electronique liee aux vitesses de Fermi et du gap, au noeud. Une discontinuite dans cette quantite pourrait signaler la traversee du dopage critique qui reconstruit la surface de Fermi. Plusieurs sondes experimentales distinguent une transition de phase ou un crossover a T* a temperature finie. D'autres sondes mettent en evidence une transition de phase sous l'effet d'un champ magnetique. La presence ou non de cet ordre, a temperature et champ magnetique nul questionne la communaute depuis plusieurs annees. Dans cette etude, nous detectons une variation brusque de kappa0/T a p = 0.18 dans YBCO et a p = 0.20 dans Tl-2201. Ces sauts sont interpretes comme un signe de la transition a temperature nulle et sont en faveur d'un QCP. Le manque de donnees d'un meme materiau a ces dopages ne permet pas de valider hors de tout doute l'existence d'un point critique quantique. Le modele theorique YRZ decrit aussi bien les donnees de conductivite thermique. Des pistes de travaux experimentaux a poursuivre sont proposees pour determiner la presence ou non du QCP de facon franche. Mots-cles : Supraconducteurs, cuprates, conductivite thermique, point critique quantique.

Barium-cross-linked alginate-gelatine microcapsule as a potential platform for stem cell production and modular tissue formation.

PubMed

Alizadeh Sardroud, Hamed; Nemati, Sorour; Baradar Khoshfetrat, Ali; Nabavinia, Mahbobeh; Beygi Khosrowshahi, Younes

2017-08-01

Influence of gelatine concentration and cross-linker ions of Ca 2+ and Ba 2+ was evaluated on characteristics of alginate hydrogels and proliferation behaviours of model adherent and suspendable stem cells of fibroblast and U937 embedded in alginate microcapsules. Increasing gelatine concentration to 2.5% increased extent of swelling to 15% and 25% for barium- and calcium-cross-linked hydrogels, respectively. Mechanical properties also decreased with increasing swelling of hydrogels. Both by increasing gelatine concentration and using barium ions increased considerably the proliferation of encapsulated model stem cells. Barium-cross-linked alginate-gelatine microcapsule tested for bone building block showed a 13.5 ± 1.5-fold expansion for osteoblast cells after 21 days with deposition of bone matrix. The haematopoietic stem cells cultured in the microcapsule after 7 days also showed up to 2-fold increase without adding any growth factor. The study demonstrates that barium-cross-linked alginate-gelatine microcapsule has potential for use as a simple and efficient 3D platform for stem cell production and modular tissue formation.

Multistage electronic nematic transitions in cuprate superconductors: A functional-renormalization-group analysis

NASA Astrophysics Data System (ADS)

Tsuchiizu, Masahisa; Kawaguchi, Kouki; Yamakawa, Youichi; Kontani, Hiroshi

2018-04-01

Recently, complex rotational symmetry-breaking phenomena have been discovered experimentally in cuprate superconductors. To find the realized order parameters, we study various unconventional charge susceptibilities in an unbiased way by applying the functional-renormalization-group method to the d -p Hubbard model. Without assuming the wave vector of the order parameter, we reveal that the most dominant instability is the uniform (q =0 ) charge modulation on the px and py orbitals, which possesses d symmetry. This uniform nematic order triggers another nematic p -orbital density wave along the axial (Cu-Cu) direction at Qa≈(π /2 ,0 ) . It is predicted that uniform nematic order is driven by the spin fluctuations in the pseudogap region, and another nematic density-wave order at q =Qa is triggered by the uniform order. The predicted multistage nematic transitions are caused by Aslamazov-Larkin-type fluctuation-exchange processes.

Electronic excitations in electron-doped cuprate superconductors

NASA Astrophysics Data System (ADS)

Unger, P.; Fulde, P.

1995-04-01

We calculate the electronic single-particle spectrum of an electron-doped cuprate superconductor such as Nd2-xCexCuO4-y. The dynamics of holes in the Cu-O planes is described by the extended Hubbard or Emery model. We consider the system at half-filling (one hole per unit cell, nh=1) and in the case of electron doping where the ground state is paramagnetic. The projection technique of Mori and Zwanzig is applied to derive the equations of motion for the Green's functions of Cu and O holes. These equations are solved self-consistently as in a previous calculation, where we considered the case of hole doping. At half-filling the system exhibits a charge-transfer gap bounded by Zhang-Rice singlet states and the upper Hubbard band. Upon electron doping the upper Hubbard band crosses the Fermi level and the system becomes metallic. With increasing electron doping the singlet band loses intensity and finally vanishes for nh=0. The corresponding spectral weight is transferred to the upper Hubbard band, which becomes a usual tight-binding band for zero hole concentration. The shape of the flat band crossing the Fermi level fits well to angle-resolved photoemission spectra of Nd2-xCexCuO4-y for x=0.15 and 0.22. Furthermore, our findings are in excellent agreement with exact diagonalization studies of 2×2 CuO2 cluster with periodic boundary conditions.

Spectroscopic investigation of the Cr to Tm energy transfer in Yttrium Aluminum Garnet (YAG) crystals

NASA Technical Reports Server (NTRS)

Dibartolo, B.

1988-01-01

New and interesting schemes have recently been considered for the efficient operation of solid-state ionic laser systems. Often the available data on these systems were obtained only because they seemed directly related to the laser performance and provide no insight into the physical processes. A more systematic approach is desirable, where more attention is devoted to the elementary basic processes and to the nature of the mechanisms at work. It is with this aim that we have undertaken the present study. Yttrium Aluminum Garnet (Y4Al5O12), called YAG, has two desirable properties as host for rare earth impurities: (1) trivalent rare earth ions can replace the yttrium without any charge compensation problem, and (2) YAG crystals have high cutoff energies. The results of measurements and calculations indicate that the Cr(3+) ion in YAG can be used to sensitize efficiently the Tm(3+) ion.

Yttrium oxide based three dimensional metamaterials for visible light cloaking

NASA Astrophysics Data System (ADS)

Rai, Pratyush; Kumar, Prashanth S.; Varadan, Vijay K.; Ruffin, Paul; Brantley, Christina; Edwards, Eugene

2014-04-01

Metamaterial with negative refractive index is the key phenomenon behind the concept of a cloaking device to hide an object from light in visible spectrum. Metamaterials made of two and three dimensional lattices of periodically placed electromagnetic resonant cells can achieve absorption and propagation of incident electromagnetic radiation as confined electromagnetic fields confined to a waveguide as surface plasmon polaritons, which can be used for shielding an object from in-tune electromagnetic radiation. The periodicity and dimensions of resonant cavity determine the frequency, which are very small as compared to the wavelength of incident light. Till now the phenomena have been demonstrated only for lights in near infrared spectrum. Recent advancements in fabrication techniques have made it possible to fabricate array of three dimensional nanostructures with cross-sections as small as 25 nm that are required for negative refractive index for wavelengths in visible light spectrum of 400-700 nm and for wider view angle. Two types of metamaterial designs, three dimensional concentric split ring and fishnet, are considered. Three dimensional structures consisted of metal-dielectric-metal stacks. The metal is silver and dielectric is yttrium oxide, other than conventional materials such as FR4 and Duroid. High κ dielectric and high refractive index as well as large crystal symmetry of Yttrium oxide has been investigated as encapsulating medium. Dependence of refractive index on wavelength and bandwidth of negative refractive index region are analyzed for application towards cloaking from light in visible spectrum.

New investigations of the guanine trichloro cuprate(II) complex crystal

NASA Astrophysics Data System (ADS)

Fabijanić, Ivana; Matković-Čalogović, Dubravka; Pilepić, Viktor; Ivanišević, Irena; Mohaček-Grošev, Vlasta; Sanković, Krešimir

2017-01-01

Crystals of the guanine trichloro cuprate(II) complex, (HGua)2[Cu2Cl6]·2H2O (HGua = protonated guanine), were prepared and analysed by spectroscopic (IR, Raman) and computational methods. A new single-crystal X-ray diffraction analysis was conducted to obtain data with lower standard uncertainties than those in the previously published structure. Raman and IR spectroscopy and quantum-mechanical analysis gave us new insight into the vibrational states of the (HGua)2[Cu2Cl6]·2H2O crystal. The vibrational spectra of the crystal were assigned by performing a normal coordinate analysis for a free dimer with a centre of inversion as the only symmetry element. The stretching vibration observed at 279 cm-1 in the infrared spectrum corresponds to the N-Cu bond. The noncovalent interaction (NCI) plots and quantum theory of atoms in molecules (QTAIM) analysis of the electron density obtained from periodic DFT calculations elucidated the interactions that exist within the crystal structure. Closed-shell ionic attractions, as well as weak and medium strength hydrogen bonds, prevailed in the crystal packing.

Photoemission perspective on pseudogap, superconducting fluctuations, and charge order in cuprates: a review of recent progress

NASA Astrophysics Data System (ADS)

Vishik, I. M.

2018-06-01

In the course of seeking the microscopic mechanism of superconductivity in cuprate high temperature superconductors, the pseudogap phase— the very abnormal ‘normal’ state on the hole-doped side— has proven to be as big of a quandary as superconductivity itself. Angle-resolved photoemission spectroscopy (ARPES) is a powerful tool for assessing the momentum-dependent phenomenology of the pseudogap, and recent technological developments have permitted a more detailed understanding. This report reviews recent progress in understanding the relationship between superconductivity and the pseudogap, the Fermi arc phenomena, and the relationship between charge order and pseudogap from the perspective of ARPES measurements.

The mass-ratio and eccentricity distributions of barium and S stars, and red giants in open clusters

NASA Astrophysics Data System (ADS)

Van der Swaelmen, M.; Boffin, H. M. J.; Jorissen, A.; Van Eck, S.

2017-01-01

Context. A complete set of orbital parameters for barium stars, including the longest orbits, has recently been obtained thanks to a radial-velocity monitoring with the HERMES spectrograph installed on the Flemish Mercator telescope. Barium stars are supposed to belong to post-mass-transfer systems. Aims: In order to identify diagnostics distinguishing between pre- and post-mass-transfer systems, the properties of barium stars (more precisely their mass-function distribution and their period-eccentricity (P-e) diagram) are compared to those of binary red giants in open clusters. As a side product, we aim to identify possible post-mass-transfer systems among the cluster giants from the presence of s-process overabundances. We investigate the relation between the s-process enrichment, the location in the (P-e) diagram, and the cluster metallicity and turn-off mass. Methods: To invert the mass-function distribution and derive the mass-ratio distribution, we used the method pioneered by Boffin et al. (1992) that relies on a Richardson-Lucy deconvolution algorithm. The derivation of s-process abundances in the open-cluster giants was performed through spectral synthesis with MARCS model atmospheres. Results: A fraction of 22% of post-mass-transfer systems is found among the cluster binary giants (with companion masses between 0.58 and 0.87 M⊙, typical for white dwarfs), and these systems occupy a wider area than barium stars in the (P-e) diagram. Barium stars have on average lower eccentricities at a given orbital period. When the sample of binary giant stars in clusters is restricted to the subsample of systems occupying the same locus as the barium stars in the (P-e) diagram, and with a mass function compatible with a WD companion, 33% (=4/12) show a chemical signature of mass transfer in the form of s-process overabundances (from rather moderate - about 0.3 dex - to more extreme - about 1 dex). The only strong barium star in our sample is found in the cluster with

BARIUM SURFACE ABUNDANCES OF BLUE STRAGGLERS IN THE OPEN CLUSTER NGC 6819

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

Milliman, Katelyn E.; Mathieu, Robert D.; Schuler, Simon C., E-mail: milliman@astro.wisc.edu

2015-09-15

We present a barium surface abundance of 12 blue stragglers (BSs) and 18 main-sequence (MS) stars in the intermediate-age open cluster NGC 6819 (2.5 Gyr) based on spectra obtained from the Hydra Multi-object Spectrograph on the WIYN 3.5 m telescope. For the MS stars we find [Fe/H] = +0.05 ± 0.04 and [Ba/Fe] = −0.01 ± 0.10. The majority of the BS stars are consistent with these values. We identify five BSs with significant barium enhancement. These stars most likely formed through mass transfer from an asymptotic giant branch star that polluted the surface of the BS with the nucleosynthesismore » products generated during thermal pulsations. This conclusion aligns with the results from the substantial work done on the BSs in old open cluster NGC 188 that identifies mass transfer as the dominant mechanism for BS formation in that open cluster. However, four of the BSs with enhanced barium show no radial-velocity evidence for a companion. The one star that is in a binary is a double-lined system, meaning the companion is not a white dwarf and not the remnant of a prior AGB star. In this paper we attempt to develop a consistent scenario to explain the origin of these five BSs.« less

Barium enema and CT volumetry for predicting pathologic response to preoperative chemoradiotherapy in rectal cancer patients.

PubMed

Murono, Koji; Kawai, Kazushige; Tsuno, Nelson H; Ishihara, Soichiro; Yamaguchi, Hironori; Sunami, Eiji; Kitayama, Joji; Watanabe, Toshiaki

2014-06-01

Preoperative chemoradiotherapy has been widely used for the prevention of local recurrence of locally advanced rectal cancer, and the effect of chemoradiotherapy is known to be associated with overall survival. We aimed to evaluate the association of the pathologic response grade with tumor recurrence rate after chemoradiotherapy, using radiographic analysis and the Response Evaluation Criteria in Solid Tumors as the parameters. This study was conducted at a single tertiary care institution in Japan. This was a retrospective cohort study of patients undergoing preoperative chemoradiotherapy. A total of 101 low rectal cancer patients receiving preoperative chemoradiotherapy from July 2004 to August 2012 were enrolled. The tumor reduction rate was measured with the use of traditional Response Evaluation Criteria in Solid Tumors, barium enema, and CT volumetry, and the correlation between the reduction rate and the pathologic response grade was examined. The tumor reduction rate assessed according to Response Evaluation Criteria in Solid Tumors showed no association with the pathologic response grade (p =0.61). In contrast, the radiographic response rate by both barium enema and CT volumetry strongly correlated with the pathologic response grade (p < 0.0001 and p = 0.001).In terms of local tumor recurrence, those diagnosed as high responders by the pathologic response grade, Response Evaluation Criteria in Solid Tumors, barium enema, and CT volumetry had a lower recurrence rate (p =0.03, p =0.03, p =0.0002, and p =0.001). The difference between high responders and low responders was especially prominent by barium enema and CT volumetry. The study is limited by its retrospective nature. Double-contrast barium enema and CT volumetry were superior to Response Evaluation Criteria in Solid Tumors in evaluating the effect of chemoradiotherapy and predicting the likelihood of tumor recurrence.

Superconducting composite with multilayer patterns and multiple buffer layers

DOEpatents

Wu, Xin D.; Muenchausen, Ross E.

1993-01-01

An article of manufacture including a substrate, a patterned interlayer of a material selected from the group consisting of magnesium oxide, barium-titanium oxide or barium-zirconium oxide, the patterned interlayer material overcoated with a secondary interlayer material of yttria-stabilized zirconia or magnesium-aluminum oxide, upon the surface of the substrate whereby an intermediate article with an exposed surface of both the overcoated patterned interlayer and the substrate is formed, a coating of a buffer layer selected from the group consisting of cerium oxide, yttrium oxide, curium oxide, dysprosium oxide, erbium oxide, europium oxide, iron oxide, gadolinium oxide, holmium oxide, indium oxide, lanthanum oxide, manganese oxide, lutetium oxide, neodymium oxide, praseodymium oxide, plutonium oxide, samarium oxide, terbium oxide, thallium oxide, thulium oxide, yttrium oxide and ytterbium oxide over the entire exposed surface of the intermediate article, and, a ceramic superco n FIELD OF THE INVENTION The present invention relates to the field of superconducting articles having two distinct regions of superconductive material with differing in-plane orientations whereby the conductivity across the boundary between the two regions can be tailored. This invention is the result of a contract with the Department of Energy (Contract No. W-7405-ENG-36).

Preparation and morphology, magnetic properties of yttrium iron garnet nanodot arrays on Gd3Ga5O12 substrate

NASA Astrophysics Data System (ADS)

Xu, Zhiwang; Zheng, Hui; Han, Mangui

2017-07-01

In this work, yttrium iron garnet nanodot array has been deposited on Gd3Ga5O12 substrate by pulsed laser deposition through an ultrathin alumina mask. The morphology and magnetic properties of YIG nanodot array have been investigated. Scanning electron microscopy displays the prepared nanodot array has a sharp distribution in diameter centered at 330 nm with standard deviation of 20 nm. X-ray diffraction θ-2θ and pole figure analysis show the yttrium iron garnet nanodot array has oriented growth. Moreover, typical hysteresis loops and ferromagnetic resonance spectra display larger coercivity and multi-resonance peaks which are ascribed to this unique structure.

Reflection of antiferromagnetic vortices on a supersonic domain wall in yttrium orthoferrite

NASA Astrophysics Data System (ADS)

Chetkin, M. V.; Kurbatova, Yu. N.; Shapaeva, T. B.; Borschegovsky, O. A.

2007-04-01

Reflection of solitary flexural waves propagating in a supersonic domain wall of yttrium orthoferrite from the domain wall part moving with the transverse-sound velocity is observed experimentally. This observation confirms that such a reflection of a solitary flexural wave leads to a change in the sign of the topological charge of the antiferromagnetic vortex accompanied by this wave, which proves a direct relationship between these two objects.

Coexistence of ΘI I-loop-current order with checkerboard d -wave CDW/PDW order in a hot-spot model for cuprate superconductors

NASA Astrophysics Data System (ADS)

de Carvalho, Vanuildo S.; Pépin, Catherine; Freire, Hermann

2016-03-01

We investigate the strong influence of the ΘI I-loop-current order on both unidirectional and bidirectional d -wave charge-density-wave/pair-density-wave (CDW/PDW) composite orders along axial momenta (±Q0,0 ) and (0 ,±Q0) that emerge in an effective hot-spot model departing from the three-band Emery model relevant to the phenomenology of the cuprate superconductors. This study is motivated by the compelling evidence that the ΘI I-loop-current order described by this model may explain groundbreaking experiments such as spin-polarized neutron scattering performed in these materials. Here, we demonstrate, within a saddle-point approximation, that the ΘI I-loop-current order clearly coexists with bidirectional (i.e., checkerboard) d -wave CDW and PDW orders along axial momenta, but is visibly detrimental to the unidirectional (i.e., stripe) case. This result has potentially far-reaching implications for the physics of the cuprates and agrees well with very recent x-ray experiments on YBCO that indicate that at higher dopings the CDW order has indeed a tendency to be bidirectional.

Anomalous dielectrophoretic behaviour of barium titanate microparticles in concentrated solutions of ampholytes

NASA Astrophysics Data System (ADS)

Flores-Rodriguez, N.; Markx, G. H.

2006-08-01

The dielectrophoretic behaviour of barium titanate (BaTiO3) particles with a mean grain size of 3 µm was studied. Suspensions of the powdered ceramic in the concentration range 0.01-1.60% (w/v) were prepared in dilute aqueous solutions of NaCl and concentrated aqueous solutions of the amphoteric molecules HEPES (N-[2-hydroxyethyl] piperazine-N'4-[2-ethanesulfonic acid] and EACA (ɛ -aminocaproic acid). When suspended in water without ampholytes, the particles showed positive dielectrophoresis (DEP) over the whole frequency range (1 kHz-20 MHz), independent of the medium conductivity or applied voltage. When amphoteric molecules were added at a final concentration of up to 0.57 M, the particles showed positive DEP at all frequencies. When the concentration of ampholytes was increased to 0.71 M, the particles showed positive DEP at frequencies up to 100 kHz and voltages lower than 12 Vpk-pk at all electrode sizes. However, at 100 kHz, when the amplitude was increased to over 12 Vpk-pk, the particles started to display negative DEP at the smallest electrode size (20 µm) and moved away from the microelectrodes, accumulating in the gap between the electrodes. At the highest voltages used (16-20 Vpk-pk), the particles were seen moving upwards and remained stably levitated above the array. For frequencies larger than 100 kHz, the particles showed positive DEP only. It is shown that such behaviour cannot be expected on the basis of the dielectric properties of barium titanate and the suspending medium, and it is suggested that this behaviour may be caused by the fact that at high amphotere concentration and voltages the electric field across the particles surpasses the dielectric strength of the BaTiO3 particles, resulting in a sudden drop in the particle's permittivity. The fact that not all particles showed negative DEP suggests a spread in the dielectric properties of barium titanate particles. Physical separation of barium titanate particles with presumably different

Oilfield scales: controls on precipitation and crystal morphology of barite (barium sulphate)

NASA Astrophysics Data System (ADS)

Stark, A. I. R.; Wogelius, R. A.; Vaughan, D. J.

2003-04-01

The precipitation and subsequent build up of barite (barium sulphate) inside extraction tubing presents a costly problem for off shore oil wells which use seawater to mobilize oil during hydrocarbon recovery. Mixing of reservoir formation water containing Ba2+ ions and seawater containing SO_42- ions results in barite precipitation within the reservoir well-bore region and piping. Great effort has been expended in designing strategies to minimize scale formation but details of the reaction mechanism and sensitivity to thermodynamic variables are poorly constrained. Furthermore, few detailed studies have been carried out under simulated field conditions. Hence an experimental programme was designed to study barite formation under environmentally relevant conditions with control of several system variables during the precipitation reaction. Synthetic sea-water and formation-water brines containing sodium sulphate and barium chloride, respectively, were mixed to induce BaSO_4 precipitation. Experiments were carried out at high temperature (100^oC) and high pressure (500 bars) in double rocking autoclave bombs. Barite formation as a function of the addition of calcium, magnesium, and a generic phosphonate based scale inhibitor was investigated whilst maintaining constant pH, temperature and ionic strength (0.5159). Additional experiments were performed at ambient conditions for comparison. Data concerning nucleation, growth rates, and crystal morphology were obtained. ICP-AES data from the supernatant product solutions showed considerable variation in quantity of barium sulphate precipitated as a function of the listed experimental variables. For example, ESEM analysis of barium sulphate crystals showed a dramatic shift in crystal habit from the typical tabular habit produced in control experiments; experiments performed in the presence of foreign cations produced more equant crystals, while those experiments completed in the presence of the phosphonate scale inhibitor

Dietary intake of barium, bismuth, chromium, lithium, and strontium in a Spanish population (Canary Islands, Spain).

PubMed

González-Weller, Dailos; Rubio, Carmen; Gutiérrez, Ángel José; González, Gara Luis; Caballero Mesa, José María; Revert Gironés, Consuelo; Burgos Ojeda, Antonio; Hardisson, Arturo

2013-12-01

The aim of this study was to analyze barium, bismuth, chromium, lithium, and strontium contents in food and beverages consumed by the population of the Canary Islands (Spain) as well as determine dietary intake of these metals in the archipelago as a whole and in its individual islands. To this end, 440 samples were analyzed by ICP-OES and GFAAS. Barium concentrations ranged from 5.210 ± 2.117 mg/kg in nuts to 0.035 ± 0.043 mg/L in water. Viscera exhibited the highest levels of bismuth (38.07 ± 36.80 mg/kg). The cold meat and sausages group stood out for its high chromium concentrations (0.494 ± 0.257 mg/kg). The highest concentration of lithium and strontium came out in nuts (8.761 ± 5.368 mg/kg and 9.759 ± 5.181 mg/kg, respectively). The total intakes of barium, bismuth, chromium, lithium, and strontium were 0.685, 1.274, 0.087, 3.674, and 1.923 mg/day, respectively. Cereals turned out to contribute most to the dietary intake of barium, bismuth, chromium, and lithium in the Canary Islands, while fruit contributes most to the strontium intake. We also performed a metal intake study by age and sex of the population and compared the outcome with data from other regions, both national and international.

Large and high-quality single-crystal growth of cuprate superconductor Bi-2223 using the traveling-solvent floating-zone (TSFZ) method

NASA Astrophysics Data System (ADS)

Adachi, Shintaro; Usui, Tomohiro; Kosugi, Kenta; Sasaki, Nae; Sato, Kentaro; Fujita, Masaki; Yamada, Kazuyoshi; Fujii, Takenori; Watanabe, Takao

In high superconducting transition temperature (high-Tc) cuprates, it is empirically known that Tc increases on increasing the number of CuO2 planes in a unit cell n from 1 to 3. Bi-family cuprates are ideal for investigating the microscopic mechanism involved. However, it is difficult to grow tri-layered Bi-2223, probably owing to its narrow crystallization field. Here, we report improved crystal growth of this compound using the TSFZ method under conditions slightly different from those in an earlier report [J. Cryst. Growth 223, 175 (2001)]. A Bi-rich feed-rod composition of Bi2.2Sr1.9Ca2Cu3Oy and a slightly oxygen-reduced atmosphere (mixed gas flow of O2 (10%) and Ar (90%)) were adopted for the crystal growth. In addition, to increase the supersaturation of the melts, we applied a large temperature gradient along the solid-liquid interface by shielding a high-angle light beam using Al foil around the quartz tube. In this way, we succeeded in preparing large (2 × 2 × 0 . 05 mm3) and high-quality (almost 100% pure) Bi-2223 single crystals. Hirosaki University Grant for Exploratory Research by Young Scientists and Newly-appointed Scientists.

Liquid-Phase Processing of Barium Titanate Thin Films

NASA Astrophysics Data System (ADS)

Harris, David Thomas

Processing of thin films introduces strict limits on the thermal budget due to substrate stability and thermal expansion mismatch stresses. Barium titanate serves as a model system for the difficulty in producing high quality thin films because of sensitivity to stress, scale, and crystal quality. Thermal budget restriction leads to reduced crystal quality, density, and grain growth, depressing ferroelectric and nonlinear dielectric properties. Processing of barium titanate is typically performed at temperatures hundreds of degrees above compatibility with metalized substrates. In particular integration with silicon and other low thermal expansion substrates is desirable for reductions in costs and wider availability of technologies. In bulk metal and ceramic systems, sintering behavior has been encouraged by the addition of a liquid forming second phase, improving kinetics and promoting densification and grain growth at lower temperatures. This approach is also widespread in the multilayer ceramic capacitor industry. However only limited exploration of flux processing with refractory thin films has been performed despite offering improved dielectric properties for barium titanate films at lower temperatures. This dissertation explores physical vapor deposition of barium titanate thin films with addition of liquid forming fluxes. Flux systems studied include BaO-B2O3, Bi2O3-BaB2O 4, BaO-V2O5, CuO-BaO-B2O3, and BaO-B2O3 modified by Al, Si, V, and Li. Additions of BaO-B2O3 leads to densification and an increase in average grain size from 50 nm to over 300 nm after annealing at 900 °C. The ability to tune permittivity of the material improved from 20% to 70%. Development of high quality films enables engineering of ferroelectric phase stability using residual thermal expansion mismatch in polycrystalline films. The observed shifts to TC match thermodynamic calculations, expected strain from the thermal expansion coefficients, as well as x-ray diffract measurements

DIAGNOSTIC ACCURACY OF BARIUM ENEMA FINDINGS IN HIRSCHSPRUNG'S DISEASE.

PubMed

Peyvasteh, Mehran; Askarpour, Shahnam; Ostadian, Nasrollah; Moghimi, Mohammad-Reza; Javaherizadeh, Hazhir

2016-01-01

Hirschsprung's disease is the most common cause of pediatric intestinal obstruction. Contrast enema is used for evaluation of the patients with its diagnosis. To evaluate sensitivity, specificity, positive predictive value, and negative predictive value of radiologic findings for diagnosis of Hirschsprung in patients underwent barium enema. This cross sectional study was carried out in Imam Khomeini Hospital for one year starting from 2012, April. Sixty patients were enrolled. Inclusion criteria were: neonates with failure to pass meconium, abdominal distention, and refractory constipation who failed to respond with medical treatment. Transitional zone, delay in barium evacuation after 24 h, rectosigmoid index (maximum with of the rectum divided by maximum with of the sigmoid; abnormal if <1), and irregularity of mucosa (jejunization) were evaluated in barium enema. Biopsy was obtained at three locations apart above dentate line. PPV, NPV, specificity , and sensitivity was calculated for each finding. Mean age of the cases with Hirschsprung's disease and without was 17.90±18.29 months and 17.8±18.34 months respectively (p=0.983). It was confirmed in 30 (M=20, F=10) of cases. Failure to pass meconium was found in 21(70%) cases. Sensitivity, specificity, PPV, and NPV were 90%, 80%, 81.8% and 88.8% respectively for transitional zone in barium enema. Sensitivity, specificity, PPV, and NPV were 76.7%, 83.3%, 78.1% and 82.1% respectively for rectosigmoid index .Sensitivity, specificity, PPV, and NPV were 46.7%, 100%, 100% and 65.2% respectively for irregular contraction detected in barium enema. Sensitivity, specificity, PPV, and NPV were 23.3%, 100%, 100% and 56.6% respectively for mucosal irregularity in barium enema. The most sensitive finding was transitional zone. The most specific findings were irregular contraction, mucosal irregularity, and followed by cobblestone appearance. A doença de Hirschsprung é a causa mais comum de obstrução intestinal pedi

Prediction of the physical properties of barium titanates using an artificial neural network

NASA Astrophysics Data System (ADS)

Al-Jabar, Ahmed Jaafar Abed; Al-dujaili, Mohammed Assi Ahmed; Al-hydary, Imad Ali Disher

2017-04-01

Barium titanate is one of the most important ceramics amongst those that are widely used in the electronic industry because of their dielectric properties. These properties are related to the physical properties of the material, namely, the density and the porosity. Thus, the prediction of these properties is highly desirable. The aim of the current work is to develop models that can predict the density, porosity, firing shrinkage, and the green density of barium titanate BaTiO3. An artificial neural network was used to fulfill this aim. The modified pechini method was used to prepare barium titanate powders with five different particle size distributions. Eighty samples were prepared using different processing parameters including the pressing rate, pressing pressure, heating rate, sintering temperature, and soaking time. In the artificial neural network (ANN) model, the experimental data set consisted of these 80 samples, 70 samples were used for training the network and 10 samples were employed for testing. A comparison was made between the experimental and the predicted data. Good performance of the ANN model was achieved, in which the results showed that the mean error for the density, porosity, shrinkage, and green density are 0.02, 0.06, 0.04, and 0.002, respectively.

Solar Twins and the Barium Puzzle

NASA Astrophysics Data System (ADS)

Reddy, Arumalla B. S.; Lambert, David L.

2017-08-01

Several abundance analyses of Galactic open clusters (OCs) have shown a tendency for Ba but not for other heavy elements (La-Sm) to increase sharply with decreasing age such that Ba was claimed to reach [Ba/Fe] ≃ +0.6 in the youngest clusters (ages < 100 Myr) rising from [Ba/Fe] = 0.00 dex in solar-age clusters. Within the formulation of the s-process, the difficulty to replicate higher Ba abundance and normal La-Sm abundances in young clusters is known as the barium puzzle. Here, we investigate the barium puzzle using extremely high-resolution and high signal-to-noise spectra of 24 solar twins and measured the heavy elements Ba, La, Ce, Nd, and Sm with a precision of 0.03 dex. We demonstrate that the enhanced Ba II relative to La-Sm seen among solar twins, stellar associations, and OCs at young ages (<100 Myr) is unrelated to aspects of stellar nucleosynthesis but has resulted from overestimation of Ba by standard methods of LTE abundance analysis in which the microturbulence derived from the Fe lines formed deep in the photosphere is insufficient to represent the true line broadening imposed on Ba II lines by the upper photospheric layers from where the Ba II lines emerge. Because the young stars have relatively active photospheres, Ba overabundances most likely result from the adoption of a too low value of microturbulence in the spectrum synthesis of the strong Ba II lines but the change of microturbulence in the upper photosphere has only a minor affect on La-Sm abundances measured from the weak lines.

Solar Twins and the Barium Puzzle

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

Reddy, Arumalla B. S.; Lambert, David L., E-mail: bala@astro.as.utexas.edu

Several abundance analyses of Galactic open clusters (OCs) have shown a tendency for Ba but not for other heavy elements (La−Sm) to increase sharply with decreasing age such that Ba was claimed to reach [Ba/Fe] ≃ +0.6 in the youngest clusters (ages < 100 Myr) rising from [Ba/Fe] = 0.00 dex in solar-age clusters. Within the formulation of the s -process, the difficulty to replicate higher Ba abundance and normal La−Sm abundances in young clusters is known as the barium puzzle. Here, we investigate the barium puzzle using extremely high-resolution and high signal-to-noise spectra of 24 solar twins and measuredmore » the heavy elements Ba, La, Ce, Nd, and Sm with a precision of 0.03 dex. We demonstrate that the enhanced Ba ii relative to La−Sm seen among solar twins, stellar associations, and OCs at young ages (<100 Myr) is unrelated to aspects of stellar nucleosynthesis but has resulted from overestimation of Ba by standard methods of LTE abundance analysis in which the microturbulence derived from the Fe lines formed deep in the photosphere is insufficient to represent the true line broadening imposed on Ba ii lines by the upper photospheric layers from where the Ba ii lines emerge. Because the young stars have relatively active photospheres, Ba overabundances most likely result from the adoption of a too low value of microturbulence in the spectrum synthesis of the strong Ba ii lines but the change of microturbulence in the upper photosphere has only a minor affect on La−Sm abundances measured from the weak lines.« less

[A Case of Small Intestinal Metastasis with Intussusception Due to Barium].

PubMed

Tsujio, Gen; Nagahara, Hisashi; Nakao, Shigetomi; Fukuoka, Tatsunari; Shibutani, Masatsune; Maeda, Kiyoshi; Matsutani, Shinji; Kimura, Kenjiro; Toyokawa, Takahiro; Amano, Ryosuke; Tanaka, Hiroaki; Muguruma, Kazuya; Yashiro, Masakazu; Hirakawa, Kosei; Ohira, Masaichi

2017-11-01

A 48-year-old man noticed nausea and took health examination. After chest X-ray and gastrointestinal barium study was underwent, he was referred to our hospital because of abnormal shadow in the chest X-ray. CT scan revealed about 4 cm tumor in the hilum of left lung and target sign in the small intestine. He was diagnosed with intussusception and emergency operation was performed. During the laparotomy, we found 2 intussusceptions in the small intestine and we performed manual reduction using Hutchinson's maneuver. We confirmed the mass in oral side of the intussusception site but we did not confirmed any tumor in anal of the intussusception. This suggests the intussusception was caused by barium. Finally 3 small intestine tumor was observed and we resected and reconstructed each of the tumor. Histopathological examination showed small intestinal metastasis from pleomorphic carcinoma of the lung.

Oesophageal narrowing on barium oesophagram is more common in adult patients with eosinophilic oesophagitis than PPI-responsive oesophageal eosinophilia.

PubMed

Podboy, A; Katzka, D A; Enders, F; Larson, J J; Geno, D; Kryzer, L; Alexander, J

2016-06-01

To date there have been no clear features that aid in differentiating patients with eosinophilic oesophagitis (EoE) from PPI-responsive oesophageal eosinophilia (PPI-REE). However, barium swallow roentgenography is a more sensitive and specific measure to detect subtle fibrostenotic remodeling changes present in EoE. We aim to characterise any clinical, endoscopic, histiological or barium roentgenographic differences between EoE and PPI-REE. To characterise any clinical, endoscopic, histiological or barium roentgenographic differences between EoE and PPI-REE. We performed a retrospective cohort analysis on data collected from a tertiary referral centre population from 2010 to 2015. Data from 66 patients with EoE and 28 patients with PPI-REE were analysed. Cases were adults who met consensus guidelines for EOE, and had a barium swallow study within 6 months of the index endoscopy. Clinical, endoscopic, histiological and barium swallow findings were collected. Patients with EoE reported similar characteristics as PPI-REE patients, except EoE patients were younger (35.6 vs. 46.6 years; P = 0.011), had earlier symptom onset (29.0 vs. 38.0 years; P = 0.026), and smaller oesophageal diameters on barium swallow (19.5 mm vs. 20; P = 0.042). Patients with EoE were more likely to have distal strictures (EoE 77% vs. 25%; P = 0.02) and, importantly, a greater likelihood of small calibre oesophagus (51.5% vs. 17.9%; P = 0.002). Moreover, EoE patients had a higher probability of developing small calibre oesophagus after 20 years of symptoms (72.3% vs. 30.2%; P = 0.074) compared to PPI-REE patients. When compared with eosinophilic oesophagitis, PPI-REE patients demonstrate findings that suggest PPI-responsive oesophageal eosinophilia to be a later onset, less aggressive form of oesophageal stricturing disease than eosinophilic oesophagitis. © 2016 John Wiley & Sons Ltd.

Results of magnetospheric barium ion cloud experiment of 1971

NASA Technical Reports Server (NTRS)

Adamson, D.; Fricke, C. L.; Long, S. A. T.

1975-01-01

The barium ion cloud experiment involved the release of about 2 kg of barium at an altitude of 31 482 km, a latitude of 6.926 N., and a longitude of 74.395 W. Significant erosion of plasma from the main ion core occurred during the initial phase of the ion cloud expansion. From the motion of the outermost striational filaments, the electric field components were determined to be 0.19 mV/m in the westerly direction and 0.68 mV/m in the inward direction. The differences between these components and those measured from balloons flown in the proximity of the extremity of the field line through the release point implied the existence of potential gradients along the magnetic field lines. The deceleration of the main core was greater than theoretically predicted. This was attributed to the formation of a polarization wake, resulting in an increase of the area of interaction and resistive dissipation at ionospheric levels. The actual orientation of the magnetic field line through the release point differed by about 10.5 deg from that predicted by magnetic field models that did not include the effect of ring current.

Thermo-optical characteristics and concentration quenching effects in Nd3+doped yttrium calcium borate glasses

NASA Astrophysics Data System (ADS)

Santos, D. R. S.; Santos, C. N.; de Camargo, A. S. S.; Silva, W. F.; Santos, W. Q.; Vermelho, M. V. D.; Astrath, N. G. C.; Malacarne, L. C.; Li, M. S.; Hernandes, A. C.; Ibanez, A.; Jacinto, C.

2011-03-01

In this work we present a comprehensive study of the spectroscopic and thermo-optical properties of a set of samples with composition xNd2O3-(5-x)Y2O3-40CaO-55B2O3 (0 ≤ x ≤ 1.0 mol%). Their fluorescence quantum efficiency (η) values were determined using the thermal lens technique and the dependence on the ionic concentration was analyzed in terms of energy transfer processes, based on the Förster-Dexter model of multipolar ion-ion interactions. A maximum η = 0.54 was found to be substantially higher than for yttrium aluminoborate crystals and glasses with comparable Nd3+ content. As for the thermo-optical properties of yttrium calcium borate, they are comparable to other well-known laser glasses. The obtained energy transfer microparameters and the weak dependence of η on the Nd3+ concentration with a high optimum Nd3+ concentration put this system as a strong candidate for photonics applications.

Emergence of microstructure and oxygen diffusion in yttrium-stabilized cubic zirconia

NASA Astrophysics Data System (ADS)

Yang, C.; Trachenko, K.; Hull, S.; Todorov, I. T.; Dove, M. T.

2018-05-01

Large-scale molecular dynamics simulations have been used to study the microstructure in Y-doped ZrO2. From simulations performed as a function of composition the dependence of microstructure on composition is quantified, showing how it is formed from two coexisting phases, and the transformation to the stabilized cubic form is observed at higher concentrations of yttrium and higher temperatures. The effect of composition and temperature on oxygen diffusion is also studied, showing strong correlations between microstructure and diffusion.

Quantitative measurements of vaporization, burst ionization, and emission characteristics of shaped charge barium releases

NASA Technical Reports Server (NTRS)

Hoch, Edward L.; Hallinan, Thomas J.; Stenbaek-Nielsen, Hans C.

1994-01-01

Intensity-calibrated color video recordings of three barium-shaped charge injections in the ionopshere were used to determine the initial ionization, the column density corresponding to unity optical depth, and the yield of vaporized barium in the fast jet. It was found that the initial ionization at the burst was less than 1% and that 0% burst ionization was consistent with the observations. Owing to the Doppler shift, the column density for optical thickness in the neutral barium varies somewhat according to the velocity distribution. For the cases examined here, the column density was 2-5 x 10(exp 10) atoms/sq cm. This value, which occurred 12 to 15 s after release, should be approximately valid for most shaped charge experiments. The yield was near 30% (15% in the fast jet) for two of the releases and was somewhat lower in the third, which also had a lower peak velocity. This study also demonstrated the applicability of the computer simulation code developed for chemical releases by Stenbaek-Nielsen and provided experimental verification of the Doppler-corrected emission rates calculated b Stenbaek-Nielsen (1989).

Praseodymium Cuprate Thin Film Cathodes for Intermediate Temperature Solid Oxide Fuel Cells: Roles of Doping, Orientation, and Crystal Structure.

PubMed

Mukherjee, Kunal; Hayamizu, Yoshiaki; Kim, Chang Sub; Kolchina, Liudmila M; Mazo, Galina N; Istomin, Sergey Ya; Bishop, Sean R; Tuller, Harry L

2016-12-21

Highly textured thin films of undoped, Ce-doped, and Sr-doped Pr 2 CuO 4 were synthesized on single crystal YSZ substrates using pulsed laser deposition to investigate their area-specific resistance (ASR) as cathodes in solid-oxide fuel cells (SOFCs). The effects of T' and T* crystal structures, donor and acceptor doping, and a-axis and c-axis orientation on ASR were systematically studied using electrochemical impedance spectroscopy on half cells. The addition of both Ce and Sr dopants resulted in improvements in ASR in c-axis oriented films, as did the T* crystal structure with the a-axis orientation. Pr 1.6 Sr 0.4 CuO 4 is identified as a potential cathode material with nearly an order of magnitude faster oxygen reduction reaction kinetics at 600 °C compared to thin films of the commonly studied cathode material La 0.6 Sr 0.4 Co 0.8 Fe 0.2 O 3-δ . Orientation control of the cuprate films on YSZ was achieved using seed layers, and the anisotropy in the ASR was found to be less than an order of magnitude. The rare-earth doped cuprate was found to be a versatile system for study of relationships between bulk properties and the oxygen reduction reaction, critical for improving SOFC performance.