Unconventional Units Research Articles

Chern, dipole, and quadrupole topological phases of a simple magneto-optical photonic crystal with a square lattice and an unconventional unit cell

For the study of topological phases in photonics, while quantum-Hall-type first-order chiral edge states are routinely realized in magneto-optical photonic crystals, higher-order topological states are mostly explored in all-dielectric photonic crystals. In this work, we study both first- and second-order topological photonic states in magneto-optical photonic crystals. In specific, we revisit a simple magneto-optical photonic crystal in a square lattice with one gyromagnetic cylinder in each unit cell. However, rather than investigating the conventional unit cell where the cylinder is at the center of the square unit cell as previous works have done, we consider a configuration where the cylinders are located at the four corners of the square unit cell and show that this configuration hosts rich topological phases, such as dual-band Chern, dipole, and quadrupole topological phases. Our detailed characterizations of these topological states are based on the Wannier bands and their polarizations via the Wilson loop and nested Wilson loop methods. We study in detail both the edge and corner states of the different topological phases and show that they exhibit a special feature of “spectrum robustness.” For example, though the edge and corner states of the dipole phases living in a band gap could be pushed into the bulk bands by tuning the boundary conditions, they can pass through the bulk bands and reappear within a different band gap. For dual-band quadrupole phases, we can find a regime where both band gaps host a set of corner states simultaneously and, intriguingly, the filling anomaly of one set of corner states can leave their signatures in the filling anomaly of the other set of corner states though they are separated by an extensive number of bulk states. The rich topological physics revealed in a simple magneto-optical photonic crystal not only provides new insights on higher-order topological phases in time-reversal symmetry-broken photonic systems, the results may also find promising applications by harnessing the potentials of both edge and corner states. Published by the American Physical Society 2024

Machine learning-enabled development of high performance gradient-index phononic crystals for energy focusing and harvesting

Gradient-index (GRIN) phononic crystals (PnCs) offer an excellent platform for various applications, including energy harvesting via wave focusing. Despite its versatile wave manipulation capability, the conventional design of GRIN PnCs has thus far been limited to relatively simple shapes, such as circular holes or inclusions. In this study, we propose a GRIN PnC comprising of unconventional unit cell designs derived from machine learning-based optimization for maximizing elastic wave focusing and harvesting. A deep neural network (NN) is trained to learn the complicated relationship between the hole shape and intensity at the focal point. By leveraging the fast inference of the trained NN, the genetic optimization approach derives new hole shapes with improved focusing performance, and the NN is updated by augmenting the new dataset to enhance the prediction accuracy over a gradually extended range of performance via active learning. The optimized GRIN PnC design exhibits 3.06 times higher wave energy intensity compared to the conventional GRIN PnC with circular holes. The performance of the best GRIN PnC within the allowable range of our machining tools was validated against experimental measurements, which shows 1.35 and 2.35 times higher focused wave energy intensity and energy harvesting output, respectively.

Geomechanical and Fracture Network Interpretation of a Devonian Outcrop

Summary The Duvernay Formation is an unconventional reservoir characterized by induced seismicity and fluid migration, with natural fractures likely contributing to both cases. An alpine outcrop of the Perdrix and Flume formations, correlative with the subsurface Duvernay and Waterways formations, was investigated to characterize natural fracture networks. A semiautomated image-segmentation and fracture analysis was applied to orthomosaics generated from a photogrammetric survey to assess small- and large-scale fracture intensity and rock mass heterogeneity. The study also included manual scanlines, fracture windows, and Schmidt hammer measurements. The Perdrix section transitions from brittle fractures to en echelon fractures and shear-damage zones. Multiple scales of fractures were observed, including unconfined, bedbound fractures, and fold-related bed-parallel partings (BPPs). Variograms indicate a significant nugget effect along with fracture anisotropy. Schmidt hammer results lack correlation with fracture intensity. The Flume pavements exhibit a regionally extensive perpendicular joint set, tectonically driven fracturing, and multiple fault-damage zones with subvertical fractures dominating. Similar to the Perdrix, variograms show a significant nugget effect, highlighting fracture anisotropy. The results from this study suggest that small-scale fractures are inherently stochastic and that fractures observed at core scale should not be extrapolated to represent large-scale fracture systems; instead, the effects of small-scale fractures are best represented using an effective continuum approach. In contrast, large-scale fractures are more predictable according to structural setting and should be characterized robustly using geological principles. This study is especially applicable for operators and regulators in the Duvernay and similar formations where unconventional reservoir units abut carbonate formations.

Opportunities for Redefining Unconventional Units

This article highlights the importance of re-defining units unconventionally with fractions. We provide three examples of tasks Grade 5 students engaged in; we highlight the creative ways that they flexibly re-defined units and engaged deeply with fractions. We offer suggestions for supporting unconventional units for promoting conceptual understanding of fractions.

An optimized probabilistic neural network with unit hyperspherical crown mapping and adaptive kernel coverage

It is important to improve the classification accuracy and reduce the storage space when probabilistic neural networks are used for pattern classification tasks. Based on a unit hyperspherical crown mapping and adaptive kernel coverage strategy, this paper presents an optimized hyperspherical crown probabilistic neural network(HCPNN). To overcome the separability problem caused by the fusion of heterogeneous samples, we adopt an unconventional unit hyperspherical crown mapping model in the sample space. Theoretical analysis indicates that nonlinear mapping can improve the separability of the original sample set under certain conditions. In addition, to optimize the pattern layer structure of probabilistic neural networks, we adopt an adaptive kernel coverage method for the training sample space to generate initial pattern nodes. The accumulation potential of the sample in each training subclass is used to measure the distribution density of different classes, and an adaptive update mechanism of potential values is established. In each iteration, nodes with high accumulation potential values are searched as pattern nodes from the dense to sparse regions. The precise position of each pattern node and the corresponding kernel width are adjusted by the Expected Maximum algorithm. Experiments show that HCPNN outperforms other algorithms with respect to the classification performance.

New Tech Accelerator Teams With Big Operators to Solve the Pilot Problem

Proving out and then scaling up a new technology are among the most challenging feats in the oil and gas business—about as dicey as drilling a wildcat well of old. What could make this uphill climb much steeper? Finding that no one wants to even test your innovation. The scenario is so common to the upstream sector that it has led to the creation of a new kind of venture capital fund based in Houston. Formally launched this year, Eunike Ventures is combining the roles of investor and technology accelerator with a third and unique prong: guaranteed pilot projects. Equinor, Anadarko, and Hess are the first oil companies to underwrite this experiment as corporate sponsors. “[Startups] can get all the funding they want and still not get any pilots,” explained Amy Henry, adding that, “the issue is making that connection point with the operators.” As chief executive officer and cofounder of Eunike, Henry sees the problem not just as an impediment to the growth of early-stage innovators but also the industry’s much-discussed quest to modernize itself through the adoption of new technologies. The industry veteran has touched all the angles of technology uptake during her career, which was punctuated by roles inside Shell’s venture and unconventional units, along with a stint in Malaysia as the chief financial officer of Petronas’ unconventional business. Upon starting Eunike, she realized that the solution to a more efficient technology evaluation and adoption process was rather simple: “You need to have operators have some skin the game.” This is different than the current formula that many of the biggest oil and gas producers have subscribed to, which dates back to the late 1990s when many of them formed venture units. The snag these groups have historically dealt with is that their investments in a new technology do not always persuade frontline field managers to share the risk by deploying it, even at a small scale. If it can be boiled down to one thing, then the bottleneck is really just about budgeting. “We understood the problem,” said Eunike’s other cofounder and chief operating officer, Thomas Henry, as he reflected on innovation projects he worked on over nearly 3 decades with Shell. “We couldn’t get our own assets to buy into some of the technologies that we developed—nobody was willing to fork up the money for field trials.” Under this new scheme, the issue is circumvented by funding a startup only after at least one of the operators in the “alliance” commit to a paid pilot. This is the trigger for Eunike to make an investment in the startup. Amy Henry said this underlines the fiduciary responsibility Eunike has to both the startup and the operators. It also reveals another aspect of the business, which is to help the operators accept the failure of a pilot despite how much they may want it to work out. “We’re not eliminating, but we are reducing internal bias,” she said. “We’ve all worked in oil and gas companies and had special projects, and it is always hard to say that something is not going well.”

Hydrocarbon saturation in Bakken Petroleum System based on joint inversion of resistivity and dielectric dispersion logs

Bakken Petroleum System (BPS) is composed of both conventional and unconventional units, which exhibits significant variations in lithology, rock texture, clay content, total organic carbon, accompanied by high connate water salinity, presence of disseminated pyrite grains, and low values of porosity. These petrophysical attributes of the BPS lead to inconsistency in the oil-in-place estimates for those obtained from Electromagnetic (EM) induction log, Nuclear Magnetic Resonance (NMR) log, dielectric dispersion log measured by Array Dielectric Tool (ADT), and Dean-Stark core measurements. For purposes of improved hydrocarbon saturation estimation and petrophysical characterization in the BPS, a joint-inversion-based interpretation was performed on dispersive electrical conductivity and dielectric permittivity measurements at 4 dielectric-log-acquisition frequencies and 1 induction resistivity acquired at 20 kHz. This analysis was performed across a 350-ft depth interval in one of the science wells intersecting the BPS. Three geo-electromagnetic mixing models, namely Complex Refractive Index model, Stroud-Milton-De model, and Waxman Smits model are integrated and coupled to the inversion scheme to simultaneously estimate water saturation, formation brine conductivity, cementation exponent and saturation exponent in BPS.Water saturation estimates obtained using the proposed interpretation method were compared against those obtained from NMR log, Dean-Stark core measurements and service company’s dielectric inversion. In Middle Bakken from depth XX720 to XX750 ft, our estimates of water saturation are in better agreement with those estimated by service company’s mineral inversion method and service company’s dielectric interpretation as compared to those obtained from NMR interpretation and Dean Stark core measurement. Water saturation and formation brine conductivity estimates in Middle Bakken are in the ranges of 0.5–1 and 25–45 S/m, respectively. Inversion-derived brine conductivity and saturation exponent estimates are most uncertain in Lodgepole and Three Forks 2 formations, which exhibit a wide range of pore size distribution. Average relative errors in matching the 1 induction resistivity and 8 dielectric dispersion logs using the inversion-derived estimates are 33% and 20%, respectively, in the 350-ft depth interval of BPS. The proposed inversion achieves high certainty for the estimates when the formation has low clay content, low electrical anisotropy, and high porosity.

Unidirectional thermal radiation from a SiC metasurface

Emission of thermal radiation from periodically patterned surfaces that support surface phonon polaritons has always been into two symmetric emission angles. This is because of the nature of randomness in the thermal spectrum of a hot body that symmetrically distributes the heat into counterpropagating surface waves. Here we demonstrate the design method of metasurfaces with unconventional unit cell dimension and internal structure to direct the thermal radiation into a single specific emission angle. We utilize a combination of diffraction order engineering and numerical optimization techniques for the design process of an ultra-thin metasurface to couple counterpropagating surface waves into a single emission direction. In addition, we compute the near-field incoherent thermal emission intensity from the metasurface by combining the concepts of fluctuation dissipation theorem with solutions of Maxwell’s equations based on rigorous coupled-wave analysis and demonstrate unidirectional phaseless thermal radiation emission. The developed approach serves as a tool to design metasurfaces for manipulation of light sources with more complex nature than a plane wave.

COMPARISON OF MATHEMATICAL MODELS FOR HEAT EXCHANGERS OF UNCONVENTIONAL CHP UNITS

An unconventional CHP unit with a hot air engine is designed as the primary energy source with fuel in the form of biomass. The heat source is a furnace designed for combustion of biomass, whether in the form of wood logs or pellets. The transport of energy generated by the biomass combustion to the working medium of a hot-air engine is ensured by a special heat exchanger connected to this resource. The correct operation of the hot-air engine is largely dependent on an appropriate design of the exchanger. The paper deals with the calculation of the heat exchanger for the applications<br />mentioned, using criterion equations, and based on CFD simulations.

STATIC TESTS OF UNCONVENTIONAL PROPULSION UNITS FOR ULTRALIGHT AIRPLANES

This paper presents static tests of a new unconventional propulsion unit for small aviation airplanes. Our laboratory stand – a fan drive demonstrator – enables us to compare various design options. We performed experiments to verify the propulsion functionality and a measurement procedure to determine the available thrust of the propulsion unit and its dependence on engine speed. The results used for subsequent optimization include the operating parameters of the propulsion unit, and the temperature and velocity fields in parts of the air duct.

A Savage Conflict: The Decisive Role of Guerrillas in the American Civil War (review)

Reviewed by: A Savage Conflict: The Decisive Role of Guerrillas in the American Civil War Samuel B. McGuire A Savage Conflict: The Decisive Role of Guerrillas in the American Civil War. By Daniel E. Sutherland. (Chapel Hill: University of North Carolina Press, 2009. Pp. xvi, 435.) Since the late 1980s, historians have advanced our understanding of the Civil War by shedding light on the unconventional warfare that wracked the war-torn South. Supplementing works by Michael Fellman, Robert Mackey, Kenneth Noe, and Phillip Paludan, Daniel E. Sutherland’s study, A Savage Conflict, is the most comprehensive analysis of Civil War guerrilla warfare to date. Sutherland examines the complex evolution of irregular warfare in the lower Midwest, the Trans-Mississippi, the upper South, and the Deep South to assert that “it is impossible to understand the Civil War without appreciating the scope and impact of the guerrilla conflict” (ix). Sutherland employs an exhaustive number of primary sources—including correspondence, newspapers, and military records—to contend that fierce guerrilla warfare played a decisive role in the Confederacy’s downfall. [End Page 107] Irregulars were a boon to the Confederacy at the war’s outset by embarking on reconnaissance missions, harassing federal supply lines, and wreaking havoc upon Union morale. However, as the war progressed, unconventional units became liabilities. Southern lawmakers passed the Partisan Ranger Act in 1862 to restrain irregulars, yet the legislation intensified guerrilla warfare, and the Confederate brass failed to integrate it into their conventional campaigns. Southern civilians also grew disenchanted with the administration in Richmond, as they found it could not protect them from the federals’ harsh anti-guerrilla reprisals and roving bands of criminals and deserters. Organized chronologically and thematically, Sutherland’s study not only distinguishes between various irregulars—bushwhackers, guerrillas, and partisans—but also provides insight into guerrillas’ motivations. Many ordinary southerners romantically associated irregulars with famous Revolutionary War partisans, especially Francis Marion, and preferred unconventional service because it allowed them to remain at home to protect family and fireside. Furthermore, guerrilla units provided an escape from the mundane “regimentation, discipline, and endless drill required in the conventional army,” and allowed individuals to employ superior combat skills including: “marksmanship, familiarity with knives and hatchets, experience as woodsmen . . . and horsemanship” (51, 52). Sutherland goes on to highlight the guerrillas’ socioeconomic backgrounds and illustrates that many were neither desperate cutthroats nor ne’er-do-wells. Instead, a number of irregulars in the upper South hailed from landowning middle-class families. Sutherland asserts that rebel guerrillas in western Virginia “included prosperous, educated, and respected leaders of their communities,” who may or may not have owned slaves, but “considered guerrilla operations the best means of resisting Union soldiers and combating neighbors” (86, 87). Sutherland also calls attention to the increasing youth of Confederate guerrillas as the war progressed. The average age of members of one Arkansas guerrilla unit in 1864 was nineteen and many had joined “in search of adventure and fun” (211). These findings are intriguing and leave readers wondering whether this was a prevalent trend in both Confederate and Union irregular companies as the war dragged on. Sutherland concludes by briefly examining the postwar legacy of guerrillas. Outbreaks of violence plagued the South during Reconstruction and many ex-Confederates formed anti-Republican guerrilla bands to influence raging political battles. Although Reconstruction-era irregulars disregarded the wartime guerrilla brand for more “colorful names, such [as] Ku Klux Klan or Knights of the White Camellia,” their methods were identical (277). [End Page 108] Because ex-Confederates purged the brutal legacy of guerrillas from public memory in an attempt to wrap the Lost Cause in a veneer of respectability, greater attention should be placed on Civil War irregulars’ postwar careers and how subsequent generations manipulated the guerrilla fighter image for partisan purposes. Sutherland’s A Savage Conflict thus illustrates the importance of irregular warfare that will surely captivate general readers and seasoned academics alike, as well as undergraduate and graduate students. Samuel B. McGuire University of Georgia Copyright © 2010 West Virginia University Press

Innovative constructions in Dutch Turkish: An assessment of ongoing contact-induced change

Turkish as spoken in the Netherlands (NL-Turkish) sounds “different” (unconventional) to Turkish speakers in Turkey (TR-Turkish). We claim that this is due to structural contact-induced change that is, however, located within specific lexically complex units copied from Dutch. This article investigates structural change in NL-Turkish through analyses of spoken corpora collected in the bilingual Turkish community in the Netherlands and in a monolingual community in Turkey. The analyses reveal that at the current stage of contact, NL-Turkish is not copying Dutch syntax as such, but rather translates lexically complex individual units into Turkish. Perceived semantic equivalence between Dutch units and their Turkish equivalents plays a crucial role in this translation process. Counter to expectations, the TR-Turkish data also contained unconventional units, though they differed in type, and were much less frequent than those in NL-Turkish. We conclude that synchronic variation in individual NL-Turkish units can contain the seeds of future syntactic change, which will only be visible after an increase in the type and token frequency of the changing units.

Fabrication by means of x-ray lithography of two-dimensional GaAs/AlGaAsphotonic crystals with an unconventional unit cell

Two-dimensional photonic crystals have been fabricated by x-ray lithography andreactive ion etching on an air/GaAs/AlGaAs asymmetric waveguide. The shape ofthe lattice unit cell has been varied by exploiting x-ray diffraction effects andnonlinear response of resists during the development process. Rings with orwithout a central pillar have been fabricated with a resolution down to 50 nm.Lithographic details are described to show the accuracy of this fabricationtechnique. Optical characterization has been performed showing the presence of awell defined photonic band structure as well as band anti-crossing. Theresults are discussed and compared with theoretical calculations of thephotonic band dispersion. Structures with high dielectric fraction areshown to yield photonic modes with small line widths and low propagationlosses. The reliability and the precise control of the fabricated samplestructures make this lithographic method useful for a full investigationof optical properties on the dependence of the lattice unit cell shape.

Optical thermophysical characteristics of the condensed phase of combustion products and heatproof materials

An unconventional unit for experimentally studying the optical thermophysical properties of materials over a wide temperature range is described. Results are presented of studying the temperature function and dispersion of the absorption index for the condensed phase of the combustion products of a metalbearing fuel and of the emittance of fiber fireproof materials.

Effect of cyclic loading on motor efficiency

A method of sizing motors is proposed which is intended to provide the least energy consumption and more starting torque. The technique compares steady-load motor efficiency with the efficiency when operated on various cyclic load configurations. The performance of unconventional and conventional pumping units is compared for calculated and measured torques. Field data are used to verify the model. For cyclic loads, motors are more efficient when operated near half-load. The reason for improved efficiency when using unconventional units is shown. It is shown that the best efficiency will be achieved with a motor operating at 40-50% of its rating. A ten-point improvement in efficiency is obtained when the motor load changes by a factor of 2 and the final load is near 50%. A motor provides adequate starting torque for a conventional unit only when the motor rating is two times the average load.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

An efficient technique for reliability analysis of power systems including time dependent sources

A method of reliability analysis of electric power systems with time-dependent sources, such as photovoltaic and wind generation is introduced. The fluctuating characteristic of unconventional generation units affects the reliability of the generation system in a different manner than the conventional units. The method proposed by the authors groups the units into several subsystems. One subsystem contains the conventional units and the remaining subsystem consist of unconventional units. A generation system model is built for each subsystem. The outputs for the unconventional units and the load are treated as correlated random variables. Using a clustering procedure states are identified wherein for a given value of load there are specific mean values of the outputs of the unconventional units. Reliability analysis is performed by combining the conventional subsystem with the unconventional subsystems in each state. The output from all the states is combined to compute the loss of load expectation and expected unserved energy.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Reliability Modeling of Generation Systems Including Unconventional Energy Sources

A method for reliability evaluation of electric power systems with unconventional energy sources, such as solar power plants and wind turbine generators, is presented. The fluctuating nature of energy produced by such unconventional units has a different effect on the overall system reliabilitv than conventional units. Methods described in the published literature appear to have several deficiencies. The method presented in this paper combines conventional and unconventional units into separate groups. The analysis proceeds by creating a generation system model for each group. The models of the unconventional groups are modified hourly depending on the limitations of energy. All the models are combined hourly to find the loss of load expectation and the frequency of capacity deficiency for the hour in question. This procedure is accomplished using a discrete state algorithm as well as the method of cumulants. Results obtained in a case study using the proposed method are described.

Engineering Geologic Data for Land-Use Planning

Engineering geologists have directed much of their effort in recent years into providing information on the geologic environment for planners and engineers. Various geologic mapping concepts, procedures, and formats have resulted, but there are two basic conceptual approaches; one involves standard geologic maps with the subsequent interpretation of engineering properties of conventional geologic units; the other requires the creation of special engineering geologic maps and the definition of new or unconventional units that may be evaluated with respect to their suitability for a particular land use. Future developments will be directed toward more comprehensive investigations, ones in which individual components of the geologic environment are studied and mapped separately, and toward the development of more representative land-use mapping units, definable with respect to the total environment and suitable for mapping and evaluation by computer analysis.