Phase resolved near-field mode imaging for the design of frequency-selective surfaces.
Abstract Not Provided
Brener, Igal↗
SEARCH · Engineering Papers
Results for “Phase field”
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Cubic-scaling algorithm and self-consistent mean field for random-phase approximation with second-order screened exchange.
Abstract not provided.
Moussa, Jonathan Edward↗
Breakdown Resistant Refractory Metal Coatings for Field-Aligned ICRF Antennas (Phase I Final Report)
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36 MATERIALS SCIENCE↗
SPE PHASE I Near-Field Data Studies
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Steedman, David Wayne↗
Verification of the SNL-SWAN Spectral WEC-wave Model with Phase-resolved Linear Wave Fields.
Abstract not provided.
Roberts, Jesse D.↗
Generation of electric-field stabilized zirconium monoxide secondary phase within cubic zirconia
Flash sintering of cubic yttria-stabilized zirconia has been studied via in situ energy dispersive diffraction. A secondary rocksalt-phase zirconium monoxide was observed emerging from the primary fluorite-phase zirconium dioxide, previously only observed as a thin interlayer at metal-oxide interfaces, upon application of a direct current electric field. The average secondary phase intensity rose over extended flow of direct current through the ceramic, faded upon removal of the field and disappeared entirely upon application of an alternating current electric field. The results indicate that the sustained application of a direct current electric field can result in significant electrochemical reduction of zirconia under high current density conditions. Poor sinterability and cracking under direct current is apparent and potential mechanisms discussed therein.
36 MATERIALS SCIENCE↗
An Assessment of Geological Carbon Storage Options in the Illinois Basin: Validation Phase
The Midwest Geological Sequestration Consortium (MGSC) assessed the options for geological carbon dioxide (CO 2 ) storage in the 155,400 km 2 (60,000 mi 2 ) Illinois Basin, which underlies most of Illinois, western Indiana, and western Kentucky. The region has annual CO 2 emissions of about 265 million metric tonnes (292 million tons), primarily from 122 coal-fired electric generation facilities, some of which burn almost 4.5 million tonnes (5 million tons) of coal per year (U.S. Department of Energy, 2010). Validation Phase (Phase II) field tests gathered pilot data to update the Characterization Phase (Phase I) assessment of options for capture, transportation, and storage of CO 2 emissions in three geological sink types: coal seams, oil fields, and saline reservoirs. Four small-scale field tests were conducted to determine the properties of rock units that control injectivity of CO 2 , assess the total storage resources, examine the security of the overlying rock units that act as seals for the reservoirs, and develop ways to control and measure the safety of injection and storage processes. The MGSC designed field test operational plans for pilot sites based on the site screening process, MVA program needs, the selection of equipment related to CO 2 injection, and design of a data acquisition system. Reservoir modeling, computational simulations, and statistical methods assessed and interpreted data gathered from the field tests. Monitoring, Verification, and Accounting (MVA) programs were established to detect leakage of injected CO 2 and ensure public safety. Public outreach and education remained an important part of the project; meetings and presentations informed public and private regional stakeholders of the results and findings. A miscible (liquid) CO 2 flood pilot project was conducted in the Clore Formation sandstone (Mississippian System, Chesterian Series) at Mumford Hills Field in Posey County, southwestern Indiana, and an immiscible CO 2 flood pilot was conducted in the Jackson sandstone (Mississippian System Big Clifty Sandstone Member) at the Sugar Creek Field in Hopkins County, western Kentucky. Up to 12% incremental oil recovery was estimated based on these pilots. A CO 2 huff puff (HNP) pilot project was conducted in the Cypress Sandstone in the Loudon Field. This pilot was designed to measure and record data that could be used to calibrate a reservoir simulation model. A pilot project at the Tanquary Farms site in Wabash County, southeastern Illinois, tested the potential storage of CO 2 in the Springfield Coal Member of the Carbondale Formation (Pennsylvanian System), in order to gauge the potential for large-scale CO 2 storage and/or enhanced coal bed methane recovery from Illinois Basin coal beds. The pilot results from all four sites showed that CO 2 could be injected into the subsurface without adversely affecting groundwater. Additionally, hydrocarbon production was enhanced, giving further evidence that CO 2 storage in oil reservoirs and coal beds offers an economic advantage. Results from the MVA program at each site indicated that injected CO 2 did not leave the injection zone. Topical reports were completed on the Middle and Late Devonian New Albany Shale and Basin CO 2 emissions. The efficacy of the New Albany Shale as a storage sink could be substantial if low injectivity concerns can be alleviated. CO 2 emissions in the Illinois Basin were projected to be dominated by coal-fired power plants.
20 FOSSIL-FUELED POWER PLANTS↗
Role of Reversible Phase Transformation for Strong Piezoelectric Performance at the Morphotropic Phase Boundary
A functional material with coexisting energetically equivalent phases often exhibits extraordinary properties such as piezoelectricity, ferromagnetism, and ferroelasticity, which is simultaneously accompanied by field-driven reversible phase transformation. The study on the interplay between such phase transformation and the performance is of great importance. Here, we have experimentally revealed the important role of field-driven reversible phase transformation in achieving enhanced electromechanical properties using in situ high-energy synchrotron x-ray diffraction combined with 2D geometry scattering technology, which can establish a comprehensive picture of piezoelectric-related microstructural evolution. High-throughput experiments on various Pb/Bi-based perovskite piezoelectric systems suggest that reversible phase transformation can be triggered by an electric field at the morphotropic phase boundary and the piezoelectric performance is highly related to the tendency of electric-field-driven phase transformation. A strong tendency of phase transformation driven by an electric field generates peak piezoelectric response. Further, phase-field modeling reveals that the polarization alignment and the piezoelectric response can be much enhanced by the electric-field-driven phase transformation. In conclusion, the proposed mechanism will be helpful to design and optimize the new piezoelectrics, ferromagnetics, or other related functional materials.
36 MATERIALS SCIENCE↗
Effect of High-Dose Carbon Implantation on the Phase Composition, Morphology, and Field-Emission Properties of Silicon Crystals
The study of high-dose carbon-ion implantation without post-process annealing reveals significant modification of the morphology, surface-layer phase composition, and field-emission properties of silicon wafers. The effect of the electrical conductivity type on the evolution of the silicon-crystal surface morphology, upon a variation in the irradiation dose, and a high content of diamond-like phases in the region of microprotrusions at the maximum dose regardless of the electrical conductivity type are found. It is demonstrated that the high-dose implantation of carbon in silicon wafers with a pre-structured surface increases the maximum density of field-emission currents by more than two orders of magnitude.
36 MATERIALS SCIENCE↗
Development of rare-earth-free bulk magnets with energy product up to 12 MGOe in field annealed Mn–Bi–Mg–In–Sb alloys
A treatment consisting of annealing in a moderately strong, ≤30 kOe, magnetic field was applied to arc-melted ingots and compacted melt-spun alloys with composition Mn 50 Bi 50-x-y-z Mg x In y Sb z . The high degree of texture of the magnetic α phase induced with annealing of the ingot samples (except the Mn–Bi–Sb one) allowed for accurate determination of the phase anisotropy field. Alloying was found to increase the anisotropy field from 45 kOe in the Mn 50 Bi 50 alloy to 65 kOe in the Mn 50 Bi 45 Mg 3 In 0.5 Sb 1.5 alloy. In the compacted melt-spun alloys subjected to field annealing, a higher degree of texture could be achieved after compaction which had involved less heating, when a smaller fraction of the metastable β' phase had been converted into the α phase; compaction at room temperature allowed for the highest degree of texture in the Mn 50 Bi 45 Mg 3 In 0.5 Sb 1.5 magnet. The addition of indium was found to decrease the solidus temperatures of the alloys, facilitating the development of the α phase during the field annealing and modifying the properties of the resulting magnets. Introduction of indium resulted in a higher coercivity H c of the Mn–Bi–Mg–In magnets and in a better texture of the Mn–Bi–Mg–Sn–In magnets. The former effect allowed, in particular, for a viable maximum energy product ( BH ) max of 10 MGOe to be developed in the Mn 50 Bi 46.5 Mg 3 In 0.5 magnet through annealing in a relatively low field of 15 kOe, whereas the latter effect allowed for an excellent combination of ( BH ) max = 11.6 MGOe and H c = 8.5 kOe in the Mn 50 Bi 45 Mg 3 In 0.5 Sb 1.5 magnet. The highest ( BH ) max of 12 MGOe was realized in the Mn 50 Bi 46 Mg 3 In 0.5 Sb 0.5 magnet.
36 MATERIALS SCIENCE↗
Phase transition preceding magnetic long-range order in the double perovskite Ba 2 NaOsO 6
Recent theoretical studies [G. Chen et al., Phys. Rev. B 82, 174440 (2010); H. Ishizuka et al., Phys. Rev. B 90, 184422 (2014)] for the magnetic Mott insulator Ba 2 NaOsO 6 have proposed a low-temperature order parameter that breaks lattice rotational symmetry without breaking time reversal symmetry, leading to a nematic phase just above the magnetic ordering temperature. We present high-resolution calorimetric and magnetization data of the same Ba 2 NaOsO 6 single crystal and show evidence for a weakly field-dependent phase transition occurring at a temperature of T s ≈ 9.5K, above the magnetic ordering temperature of T c ≈ 7.5K. This transition appears as a broadened step in the low-field temperature dependence of the specific heat. The evolution of the phase boundary with applied magnetic field suggests that this phase coincides with the phase of broken local point symmetry seen in NMR experiments at high fields [L. Lu et al., Nat. Commun. 8, 14407 (2017)]. Here, the magnetic field dependence of the specific heat provides clear indications for magnetic correlations persisting at temperatures between T c and T s where long-range magnetic order is absent, giving support for the existence of the proposed nematic phase.
36 MATERIALS SCIENCE↗
High-field superconducting halo in UTe 2
The heavy fermion material UTe 2 is a candidate topological superconductor that exhibits multiple magnetic field–induced superconducting phases. One such phase exists only at fields greater than 40 tesla, a considerable scale given its critical temperature of only 2 K. Here, in this work, we extend measurements of this state with fields outside of the bc crystallographic plane and reveal its core structure: The superconducting phase wraps around the b axis in a halo-like fashion and appears to be stabilized by a field component perpendicular to the magnetic easy axis. This angle dependence points to a multicomponent spin-triplet order parameter with a finite angular momentum of the Cooper pairs. The pairing mechanism remains enigmatic, and UTe 2 ’s specific magnetophilic superconducting tendencies seem incompatible with existing models for field-enhanced superconductivity.
Lewin, Sylvia K. [National Inst. of Standards and ↗
Self-pumped and double phase conjugation in GaAs with applied dc electric field
Self-pumped and double phase conjugation are first demonstrated in undoped GaAs with applied dc electric field at 1.06 micron wavelength. Phase-conjugate reflectivities of up to 3 percent and 0.5 percent, respectively, are obtained and other dependences are reported. Reported values of the self-pumped phase-conjugate reflectivity are compared with those of InP.
Chua, P. L.↗
Sub-Kelvin magnetic and electrical measurements in a diamond anvil cell with in-situ tunability
We discuss techniques for performing continuous measurements across a wide range of pressure-field-temperature phase space, combining the milli-Kelvin temperatures of a helium dilution refrigerator with that of the giga-Pascal pressures of a diamond anvil cell and the Tesla magnetic fields of a superconducting magnet. With a view towards minimizing remnant magnetic fields and background magnetic susceptibility, we then characterize high-strength superalloy materials for the pressure cell assembly, which allows high fidelity measurements of low-field phenomena such as superconductivity below 100 mK at pressures above 10 GPa. In situ tunability and measurement of the pressure permit experiments over a wide range of pressure, while at the same time making possible precise steps across abrupt phase transitions such as that from insulator to metal.
36 MATERIALS SCIENCE↗
Thermodynamical properties of graphene in noncommutative phase–space
We investigated the thermodynamic properties of graphene in a noncommutative phase–space in the presence of a constant magnetic field. In particular, we determined the behaviour of the main thermodynamical functions: the Helmholtz free energy, the mean energy, the entropy and the specific heat. The high temperature limit is worked out and the thermodynamic quantities, such as mean energy and specific heat, exhibit the same features as the commutative case. Possible connections with the results already established in the literature are discussed briefly.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
Wave breaking phenomenon of lower-hybrid oscillations induced by a background inhomogeneous magnetic field
In a fluid description, we study space-time evolution of lower hybrid modes in a cold quasi-neutral homogeneous plasma in presence of a background inhomogeneous magnetic field. Within a linear analysis, a dispersion relation with inhomogeneous magnetic field shows 'phase mixing' of such oscillations. A manifestation of 'phase mixing' is shown in 'mode coupling.' By using Lagrangian variables, an exact solution is presented in parametric form of this nonlinear time dependent problem. It is demonstrated that initially excited lower hybrid modes always break via phase mixing phenomenon in presence of an inhomogeneous magnetic field. Breaking of such oscillations is revealed by the appearance of spikes in the plasma density profile.
42 ENGINEERING↗
Multidimensional spectroscopy with a single broadband phase-shaped laser pulse
We calculate the frequency-dispersed nonlinear transmission signal of a phase-shaped visible pulse to fourth order in the field. Two phase profiles, a phase-step and phase-pulse, are considered. Two dimensional signals obtained by varying the detected frequency and phase parameters are presented for a three electronic band model system. We demonstrate how two-photon and stimulated Raman resonances can be manipulated by the phase profile and sign, and selected quantum pathways can be suppressed.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
CHP Integrated with Burners for Packaged Boilers (Final Report)
The objective of this project was to engineer, design, fabricate, and field demonstrate a Boiler Burner Energy System Technology (BBEST) that integrates a low-cost, clean burning, gas-fired simple-cycle (unrecuperated) 100 kWe (net) microturbine (SCMT) with a new ultra low-NOx gas-fired burner (ULNB) into one compact Combined Heat and Power (CHP) product that can be retrofit on new and existing industrial and commercial boilers in place of conventional burners. The Scope of Work for this project was segmented into two principal phases: (Phase I) Hardware development, assembly and pre-test and (Phase II) Field installation and demonstration testing. Phase I was divided into five technical tasks (Task 2 to 6). These tasks covered the engineering, design, fabrication, testing and optimization of each key component of the CHP system principally, ULNB, SCMT, assembly BBEST CHP package, and integrated controls. Phase I work culminated with the laboratory testing of the completed BBEST assembly prior to shipment for field installation and demonstration. Phase II consisted of two remaining technical tasks (Task 7 and 8), which focused on the installation, startup, and field verification tests at a pre-selected industrial plant to document performance and attainment of all project objectives. Technical direction and administration was under the management of CMCE, Inc. Altex Technologies Corporation lead the design, assembly and testing of the system. Field demonstration was supported by Leva Energy, the commercialization firm founded by executives at CMCE and Altex. Leva Energy has applied for patent protection on the BBEST process under the trade name of Power Burner and holds the license for the burner currently used in the product. The commercial term Power Burner is used throughout this report to refer to the BBEST technology proposed for this project. The project was co-funded by the California Energy Commission and the Southern California Gas Company (SCG), a division of Sempra Energy. These match funds were provided via concurrent contracts and investments available via CMCE, Altex, and Leva Energy The project attained all its objectives and is considered a success. CMCE secured the support of GI&E from Italy to supply 100 kW Turbec T-100 microturbines for the project. One was purchased by the project’s subcontractor, Altex, and a second spare was purchased by CMCE under this project. The microturbines were then modified to convert from their original recuperated design to a simple cycle configuration. Replacement low-NOx silo combustors were designed and bench tested in order to achieve compliance with the California Air Resources Board (CARB) 2007 emission limits for NOx and CO when in CHP operation. The converted microturbine was then mated with a low NOx burner provided by Altex via an integration section that allowed flow control and heat recovery to minimize combustion blower requirements; manage burner turndown; and recover waste heat. A new fully integrated control system was designed and developed that allowed one-touch system operation in all three available modes of operation: (1) CHP with both microturbine and burner firing for boiler heat input greater than 2 MMBtu/hr; (2) burner head only (BHO) when the microturbine is under service; and (3) microturbine only when boiler heat input requirements fall below 2 MMBtu/hr. This capability resulted in a burner turndown performance of nearly 10/1, a key advantage for this technology over conventional low NOx burners. Key components were then assembled into a cabinet with additional support systems for generator cooling and fuel supply. System checkout and performance tests were performed in the laboratory. The assembled system and its support equipment were then shipped and installed at a host facility where final performance tests were conducted following efforts to secure fabrication, air, and operating permits. The installed power burner is now in commercial operation and has achieved all the performance goals.
20 FOSSIL-FUELED POWER PLANTS↗