bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sintering Time and Temperature for Ba2YCu3O7−x Superconductors
Authors: Taylor Jenifer A.T. , Sainamthip Prinya , Dockery David F. 
Published: March 2011

ABSTRACTSintering at temperatures in excess of the melting point for followed by soaking at 980 C for extended periods results in domain-type microstructure and grain orientation in samples that demonstrate zero resistivity and significant Meissner effect.
Bulk Ceramic and Screen Printed EuBa2Cu3O7-δ
Authors: Fu W. S. , Ginley D. S. , Mitchell M. A. , Venturini E. L. , Morosin B. , Kwak J. F. , Baughman R. J. 
Published: March 2011

ABSTRACTThe structural, magnetic and electrical properties of EuBa2Cu3O7-δ have been investigated both for bulk ceramics and screen printed thick films. The bulk ceramic reaches zero resistance at 92 K, and has large intragranular critical current density inferred from magnetization loops; the directly measured critical current density is substantially lower because of the weak links (Josephson junctions) between grains. Screen printed thick films on strontium titanate have poor magnetic and resistive transitions with evidence for two phases. High temperature oxygen anneals produce a bulk ceramic with significantly enhanced magnetic properties.
Freestanding Films of YBa2cu3O6.9
Authors: Ginley D. S. , Mitchell M. A. , Fu W. , Kwak J. F. , Venturini E. L. , Baughman R. J. 
Published: March 2011

ABSTRACTThick (20–300 /im) freestanding films of ceramic YBa2Cu3O0–9 have been obtained by resintering YBa2Cu3O0–9 powder in air after screen printing onto fused silica substrates. An interfacial reaction occurs between the powder and the silica substrate which efficiently debonds the resintered film upon cooling. The magnetization and transport properties of these films are comparable to those for high quality bulk ceramic samples.
Superconducting Tape-Shaped Wire by Y1Ba2cu3o7-δ with Jc ≈ 2000 A/cm2
Authors: Matsuda S. , Okada M. , Morimoto T. , Matsumoto T. , Ihara K. 
Published: March 2011

ABSTRACTA tape-shaped wire with Y1 Ba2Cu3, O7-δ, core and Ag sheath was fabricated by a drawing-rolling method. The critical current density of the wire with 0.1 mm thickness and 6 mm width was in 2 the range of 2000 A/cm at 77 K in the absence of external magnetic field. Presence of 20 m Tesla magnetic field reduced the J value to 1/100.
Thermal Conductivity of Substituted Perovskite Superconductors
Authors: Heremans J. , Morelli D. T. 
Published: March 2011

ABSTRACTMeasurements of the thermal conductivity of rare earth-barium-copper-oxide superconductors are presented. Heat conduction occurs principally by phonons, and increases below the transition temperature due to a decrease in electron scattering. This implies a strong electron-phonon coupling, and estimates for the coupling constant and transition temperatures are obtained within the framework of BCS theory.
Tunneling Measurements of Density of States in Superconducting YBa2Cu3Oy
Authors: Ida K.I , Gotoh K. , Enomoto H. , Takano Y. , Mori N. , Ozaki H. 
Published: March 2011

ABSTRACTTunneling measurements were applied to investigate the density of states of the high Tc superconductor in the temperature range from 4.2 K to the transition temperature. Several structures were found in conductance curves in higher bias region than ever reported, and they vanished around Tc. Temperature dependence of the bias voltages at which these structures appeared showed the BCS-like behavior.
Vibrational Raman Scattering from high TC single Crystals
Authors: Krol D. M. , Stavola M. , Schneemeyer L. F. , Waszczak J. V. , Weber W. 
Published: March 2011

ABSTRACTPolarized Raman spectra have been measured on single crystals of the high Tc materials A2BCu3Ox with A=Ba and Sr, B=Y and La and 6<x<7. The dependence of the 500 cm-i peak position (αzz)on chemical composition is in agreement with its assignment to the O(1) axial stretching vibration. The intensity of the 600 cm1 band, which has been ascribed to a defect induced Cu-O mode, strongly depends on the crystal preparation and resulting purity.
Atomistic Lattice Calculations of the defect Properties of U2CuO4, Related to high Tc Superconductivity
Authors: Allan N. L. , Mackrodt W. C. 
Published: March 2011

ABSTRACTCalculations are reported of the perfect lattice and defect properties of the two phases of La2−x(ba,sr)xCuO4 [1] there has been intense interest, both experimental and theoretical, in materials of this type. To date, however, there appears to be no detailed account of the defect structure of La2CuO4 or La2−x(Ba,Sr)xCuO4, despite the evident importance of defect-related properties associated with the processing of these materials and the role that hole states, oxygen vacancies and impurities play in determining Tc. Accordingly, the present paper reports what are believed to be the first atomistic lattice calculations of the point defect properties of La2CuO4 related to high TC superconductivity.
High-Resolution X-Ray Microstructural Study of Single Crystals of YBa2Cu3O7-y
Authors: You Hoydoo , Axe J. D. , Kan X. B. , Moss S. C. , Liu J. Z. , Lam D. J. 
Published: March 2011

ABSTRACTSingle crystals of YBa2Cu3O7-y were studied by transmission Laue photography and monochromatic diffraction techniques, using the Cornell High Energy Synchrotron Source and a rotating anode x-ray source. A new type of twinning, with two orthorhombic domains rotated exactly 90 degree about the c axis, was observed in one sample and the conventional (110) type twinning in another sample with nominally identical growth conditions. A high resolution diffraction study of the sample with the conventional (110) twinning shows that measured orthorhombicity (proportional to oxygen ordering parameter) varies from one domain to another.
A Tunneling Study of Superconducting YBa2 Cu3Oy By Contact Junctions At 77 K
Authors: Enomoto H. , Gotoh K. , Iida K. , Takano Y. , Mori N. , Ozaki H. 
Published: March 2011

ABSTRACTGiaever tunneling measurements have been applied to investigate the electronic structures of the high Tc superconductor YB2Cu3Oy near Tc. The superconducting energy gap of 17 meV was observed in V-dl/dv curve at 77 K. In the light of BCS model, 2Δ0Δ/kBTc was estimated as 3.3. Several dip structures were observed in the bias region up to 0.5 eV in V-dl/dV curve, using the 3rd derivative analysis. Through the temperature dependence, these structures were found to be associated with the superconductivity.
Magnetisation and Critical Currents in High Tc Powders
Authors: Campbell A. M. , Hibbs A. D. , Eberharde J. , Male S. , Ashby M. F. , Evetts J. E. 
Published: March 2011

ABSTRACTMagnetisation curves have been measured on powders of various sizes. The hysteresis decreases with size for articles smaller than 20μ showing that barriers to current flow are at least this far apart. The current density is 6×106 amps/cm2 at 1.5T and this is consistent with theoretical calculations of Jc. Inductive transitions are consistent with a penetration depth of about 0.5μ at 78K. The results of Hot Isostatic Pressing are also discussed.
Differential Scanning Calorimetry and Guinier Camera/High-Temperature X-Ray Diffraction Studies of the Oxygen Sublattice Phase Transition in the Yba2Cu3O7−x System
Authors: Lee David S. , Fu Zezhong , Hellstern Egon , Johnson William L. , Pietrokowsky Paul , Samwer Konrad 
Published: March 2011

ABSTRACTWe have studied the phase transition of the oxygen sublattice in the YBa2Cu3O7−x system by Differential Scanning Calorimetry (DSC), Guinier Camera, and high temperature x-ray diffraction (ht-xrd) techniques. The transition was examined under different thermodynamic constraints (constant oxygen partial pressure and constant oxygen concentration) and for a range of oxygen partial pressures. The variation of the endothermic peak temperature with DSC scanning rate was used to deduce an activation energy for the transition. The average activation energy for the process is between 38.7–75.0 kcal/mole(l:2:3) [mole], depending on the thermodynamic constraint imposed on the system.Pressure versus concentration isotherms (P(C)) were used to determine the chemical potential of the oxygen in this system.
Hydrogen in YBA2CU3O7−x High TC Superconductors
Authors: Berning P. , Collazo J. , Mashayekhi A. , Benenson R. E. 
Published: March 2011

ABSTRACTWe have been investigating the possibility that the presence or absence of hydrogen may influence the electrical properties of the high TQ superconductor YBa2Cu3O7−x. Samples were prepared sintering in wet and dry oxygen, ana have been loaded by exposure to a plasma discharge of hydrogen gas. The hydrogen concentration near the surface was monitored by the H(15N, αγ) C reaction, and the four point method was used for the electrical measurements. The tentative results are that hydrogen content has little effect on either the transition temperature or the sharpness of the transition, although higher concentration may increase the normal state resistivity.
Aluminum Incorporation in Cuprate Perovskites
Authors: Siegrist T. , Schneemeyer L. F. , Waszczak J. V. , Sunshine S. A. , Singh N. P. , Opila R. L. , Batlogg B. , Rupp L. W. , Murphy D. W. 
Published: March 2011

ABSTRACTAluminum incorporation in cuprate perovskite single crystals has been studied by single crystal x-ray diffraction. We find that Al substitutes for copper in the Cu-O chains only. Superconducting transition temperatures, Tc, determined by dc diamagnetic susceptibility measurements, change only slightly, to «80K for ×=0.l, then drop sharply with higher aluminum concentrations.
Finite Element Analysis Animated Simulation of Velopharyngeal Closure
Authors: Srodon P.D. , Miquel M.E. , Birch M.J. 
Published: March 2011

Objective To use finite element analysis animated simulations to investigate factors affecting velopharyngeal closure. Design A coronal section multicomponent finite element analysis model of a human soft palate was created in Simulia Abaqus 6.5–1 from high resolution WIR I images of a single adult female subject, interpreted by reference to published anatomic dissections. Tissues were assigned hyperelastic property coefficients for neo-Hookean behavior, with gravity at 9.8 ms–2 in the y-axis. Vector forces based on estimations in previous publications were applied throughout levator veli palatini and palatopharyngeus muscles, using a nonlinear analysis algorithm, to produce animated simulations of velopharyngeal space closure. Variation of levator veli palatini angle from 60° to 49°, the contribution of palatopharyngeus muscle, and the effect of submucous cleft were investigated for their effects on velopharyngeal closure. Results The animated simulations showed anthropomorphic behavior and supported the previously suggested effects of the levator veli palatini angle, with reduced effectiveness of velopharyngeal closure as levator veli palatini angle decreases. Palatopharyngeus action reduced the efficiency of closure for a levator veli palatini angle of 60°, and a submucous cleft reduced this for both our normal subject and for a levator veli palatini angle of 60°, but both palatopharyngeus action and a submucous cleft enhanced closure for a levator veli palatini angle of 49°. Conclusions This study advances soft palate finite element analysis to a real-subject-based multicomponent hyperelastic model that demonstrates anthropomorphic behavior. Animated simulations using the model demonstrate the possible effects of levator veli palatini angle, a submucous cleft, and the contribution of the palatopharyngeus.
Size, Weight and Power Efficiency for High-power, Nonlinear, Geophysical-transmitter, Rod-core Antennas
Authors: Jordan Jared Williams , Sternberg Ben K. , Dvorak Steven L. 
Published: March 2011

There is a significant body of work that addresses the use of rod-core antennas as receiver coils. However, research on the use of rod-core antennas as transmitters is limited since high-permeability core materials are nonlinear at high-drive levels. This paper analyzes weight, power and volume efficiencies of rod cores constructed from six different materials: two types of ferrite toroids; black-oxide, low-carbon-steel wire; two types of Metglas foil tapes; and Nanocrystalline material foil tape. Weight efficiency is defined as the ratio of the antenna’s magnetic moment to the sum of the antenna’s core, wire and battery weights. Likewise, power efficiency is defined as the ratio of the antenna’s magnetic moment and the antenna’s resistive power losses, and volume efficiency is defined as the ratio of the antenna’s magnetic moment and the antenna’s volume. The magnetic moment, core-series-loss-resistance, and inductance were measured at various magnetic core flux densities. These data were then modified to simulate the effects of changing the wire gauge and number of turns to determine the optimum drive level and coil design for a specific rod core. Furthermore, we compare the results to an air-core loop whose length of one side is comparable to the length of the constructed rod antennas. It is shown that rod-core antennas possess significant advantages over air-core transmitters in weight, power and volume efficiency for the types of antennas investigated here. Specifically, at [Formula: see text], the maximum weight efficiency for a [Formula: see text] long rod antenna made from Metglas was found to be 310% larger than a [Formula: see text] air-core antenna. The power efficiencies associated with the maximum weight efficiencies for these two cases differ by 420%. The volume efficiency of the Metglas rod antenna was calculated as about 500% larger than the [Formula: see text] air-core antenna.
Rigorous Identification of Unplanned and Invisible Lost Time for Value Added Propositions Aimed at Performance Enhancement
Authors: Spoerker Hermann , Thonhauser Gerhard , Maidla Eric 
Published: March 2011

Abstract
During the SPE ATW on Automation (April 13-14, 2010 in Galveston), it was identified that one of the major opportunities in the Drilling and Completions industry is the identification of non-planned events, including invisible lost time with the objective to improve performance by building a value added proposition that involves operators, service companies, contractors and equipment manufactures.
The key point was to share risk and reward by using an unbiased system that is able to accurately measure, in an automated form, most of the routine drilling and completions operations that will be compared against pre-agreed benchmarks to establish if the goals and objectives are being achieved.
The technology presented in this paper explains how automatic operations detection are carried out to address the proposed challenges and the necessary reporting and user interaction needed. The theory and one case history on this will be presented and will cover the start up phase of such initiative, and all of its push backs, and lead the readers through the implementation and final results that were successfully achieved.
Psychological Effect on HSE Behaviour-New Initiative from a Drilling Team
Authors: Al-Mehailani Mohannad , Al-Hindi Khaled , Gohain Ashis , Muqeem Saleh , Akhtar Safi , Al-Rakdan Abdulwahab 
Published: March 2011

Abstract
"Making sure people are not harmed is how we do things in our workplaces" are the slogans consistently being instilled into the minds of every personnel in our workplaces. In spite of consistent campaign for HSE compliances, crew is often caught in unsafe acts. To minimize such unsafe acts, Drilling &Workover Team had conceptualized a new approach and implemented for the first time in the company. The program is basically an approach for improving safety performance through psychology. Proper implementations of this safety program will soon surpass the effectiveness of some traditional safety programs.
The program involves a jacket, with a slogan on its back "Caught in Unsafe Act… our company needs you…" kept under the custody of company man of the Rig. In a nutshell, this safety program is like a game: any person caught in an unsafe act has to keep wearing that jacket, as a penalty for the violation, till another person is caught doing some unsafe act. It labels the person as a violator and represents the violator as a man needs to be watched, among the crewmembers. The way of representation of the violator tends to stir up more HSE awareness, develop better HSE attitude and culture, among other fellow workers to ward off such representation.
The program has been launched for the first time the company at one of the drilling rigs and, it has yielded amazing results. With the implementation of this program, number of near misses and incidents declined substantially. The program is ongoing and efforts are underway, to further strengthen its effectiveness. The results of that chosen rig established the program's inbuilt potential for raising safety at workplaces to much higher echelons.
A Historical Review of Drill Pipe Capabilities and the Triggers for Change
Authors: Redlinger Thomas M. , McCormick John 
Published: March 2011

Abstract
Until very recently, drill pipe capacity has rarely been the limitation that controlled the ultimate depth or design of a wel l. Over the last 50 years drill pipe tensile and torsional capacities have typically exceeded the needs in most drilling applications; consequently, the significant separation between the capacity of the drill pipe and the actual needs of the well designs has resulted in the drill pipe being considered "dumb iron." The recent trend to drill deeper and longer reach wells has begun to push the limits of the drill pipe capacities. Improvements in drill pipe and connection technology as well as performance reliability have significantly enhanced our ability to drill these wells. Without further improvements to materials, connections and fatigue life, the capabilities of the drill pipe could become the limiting factor in some of the exciting new projects on the horizon. It is essential that manufacturers and suppliers play a larger role in well planning in order to mitigate these limitations and make sure the technologies required are available to the industry in time to coincide with the development.
This paper will review the evolution of drill pipe capabilities and compare the historical expectations of the well designs. It will also review the triggers that created the need for adoption of new grades and connection standards. Lastly, it will discuss the pending new drill pipe technologies and their effect on capacity improvements.
New Technology, Which Enables Closed, Looped Drilling (MPD) from Mobil Offshore Drilling Units (MODU)
Authors: Andresen Jan Atle , Askeland Tom 
Published: March 2011

Abstract
Siem WIS has developed a new seal solution that will be installed inside a riser below the slip joint; this will enable Managed Pressure Drilling from MODU utilizing standard equipment (slip joint etc.)
The new technology will give the operator at all time status of the seals and gives time to evaluate before entering into a well control situation.
The sealing method also enables a quick replacement of the seal package and can also be developed with several seal packages in series.
The well pressure is distributed over several seals with gradient chambers between and is monitored at all time. The stationary seals are lubricated directly into the seal area which then keeps the friction and temperature low.
Wellbore Stability Modeling and Real-Time Surveillance for Deepwater Drilling to Weak Bedding Planes and Depleted Reservoirs
Authors: Lang James , Li Shuling , Zhang Jincai 
Published: March 2011

Abstract
Wellbore instability is the primary cause of losses in boreholes and represents a serious challenge in the drilling industry. Drilling along bedding planes and in depleted reservoirs is risky, and when a well is drilled at shallow angles to thinly bedded shales, it is often highly unstable. Rock failure can occur as a result of large anisotropy in rock strength caused by bedding-parallel weak planes. In these cases, an increased mud weight while drilling is required. However, when the reservoir immediately beneath the bedded shales is depleted, the increased mud weight can lead to lost circulation. This paper presents some of the cases we encountered in surveying offset wells in depleted reservoirs located in deepwater Gulf of Mexico for a new predrill study, where borehole instabilities resulted in a loss of a hole section and a casing shoe became massively fractured.
The key solutions are to not only improve wellbore stability modeling associated with bedding planes, rock anisotropy, and pressure depletion, but also to account for their impact on horizontal stresses. These factors are considered in the proposed model, thereby enabling calculations of wellbore failures along borehole trajectories with various drilling orientations versus bedding directions. The model has been verified by case studies. The minimum stress and fracture gradient calculations are also implemented to consider rock anisotropy and the depletion. Lab test data of rock strengths with different loading directions are analyzed. A new correlation is developed to allow for predicting anisotropic rock strength from sonic velocities.
Overcoming Challenges for Drilling High-Dogleg-Severity Curves
Authors: Janwadkar S. , Hummes O. , Peter A. , Freeman M. , Privott S. , Greene D. , Loesel C. 
Published: March 2011

Abstract
Shale-gas plays and other unconventional resources have gained significant prominence in the USA and several other parts of the world. Maximizing well productivity and improving drilling efficiency remains a major challenge. Well placement in the sweet spot and extended laterals help maximize productivity. Drilling a high-dogleg-severity (DLS) curve maximizes the length of lateral in the productive zone. Wells in US shale-gas plays and other unconventional resources require a DLS of 10° to 14°/100 ft. Achieving high DLS with steerable motors presents numerous drilling challenges. Rotating a steerable motor with high adjustable kickoff (AKO) sub settings could result in fatigue failure. Alternate drilling in slide-rotate modes reduces drilling efficiency, increases tortuosity, and limits well placement in the productive zone. In the past, drilling high-DLS curves with rotary steerable systems (RSS) was a challenge. These challenges led to the development and ultimately the successful testing of a new high-dogleg RSS. Using the new system enabled drilling all sections, including high-DLS curves, tangents and laterals with one bottom hole assembly (BHA). Using closed-loop control and a short steering sleeve that decouples steering functionality from drilling dynamics, the system can drill high-DLS curves and extended reach laterals with precise well placement and improved borehole quality. The authors will discuss the design, and field test results in different environments such as shale-gas plays and tight sands. The new system significantly improves drilling performance with excellent directional control. Drilling high-DLS curves increases the length of laterals by several hundred feet, enabling additional recovery of hydrocarbons. The ability to drill all sections with one system and elimination of slide drilling significantly reduces drilling time and eliminates trips to make changes to the BHA. By minimizing wellbore tortuosity, the new system enables setting casing easily and quickly, leading to early production. Minimized tortuosity in the lateral also enables faster drilling out of completion plugs with coil tubing. The innovative system can be used in similar areas of the world to drill complex wells with high DLS and straight laterals with precision and efficiency.