Статті в журналах: "Synthetic Geometries"

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Hazzard, Kaden R. A., and Bryce Gadway. "Synthetic dimensions." Physics Today 76, no. 4 (April 1, 2023): 62–63. http://dx.doi.org/10.1063/pt.3.5225.

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Day, Jeffrey L., and Brian T. Rex. "Everyday Geometries: Synthetic Facts and Superficial Qualities." Journal of Architectural Education 57, no. 2 (November 2003): 29–35. http://dx.doi.org/10.1162/104648803770558969.

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Reigh, Shang Yik, and Raymond Kapral. "Catalytic dimer nanomotors: continuum theory and microscopic dynamics." Soft Matter 11, no. 16 (2015): 3149–58. http://dx.doi.org/10.1039/c4sm02857k.

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Marston, Timothy, and Jermaine L. Kennedy. "Scan geometries for three dimensional synthetic aperture sonar tomography." Journal of the Acoustical Society of America 140, no. 4 (October 2016): 3347. http://dx.doi.org/10.1121/1.4970696.

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Sarkar, Kanad, Manan Mittal, Ryan M. Corey, and Andrew C. Singer. "Manifold learning for dynamic array geometries." Journal of the Acoustical Society of America 152, no. 4 (October 2022): A143. http://dx.doi.org/10.1121/10.0015835.

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Large-scale distributed arrays can obtain high spatial resolution, but they typically rely on a rigid array structure. If we want to form distributed arrays from mobile and wearable devices, our models need to account for motion. The motion of multiple microphones worn by humans can be difficult to track, but through manifold techniques we can learn the movement through its acoustic response. We show that the mapping between the array geometry and its acoustic response is locally linear and can be exploited in a semi-supervised manner for a given acoustic environment. We will also investigate generative modelling of microphone positions based on their acoustic response to both synthetic and recorded data. Prior work has shown a similar locally linear mapping between source locations and their spatial cues, and we will attempt to combine these findings with our own to develop a localization model suitable for dynamic array geometries.

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Smponias, Theodoros. "Synthetic Neutrino Imaging of a Microquasar." Galaxies 9, no. 4 (October 19, 2021): 80. http://dx.doi.org/10.3390/galaxies9040080.

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Microquasar binary stellar systems emit electromagnetic radiation and high-energy particles over a broad energy spectrum. However, they are so far away that it is hard to observe their details. A simulation offers the link between relatively scarce observational data and the rich theoretical background. In this work, high-energy particle emission from simulated twin microquasar jets is calculated in a unified manner. From the cascade of emission within an element of jet matter to the dynamic and radiative whole jet model, the series of physical processes involved are integrated together. A programme suite assembled around model data produces synthetic images and spectra directly comparable to potential observations by contemporary arrays. The model is capable of describing a multitude of system geometries, incorporating increasing levels of realism depending on need and available computational resources. As an application, the modelling process is applied to a typical microquasar, which is synthetically observed from different angles using various imaging geometries. Furthermore, the resulting intensities are comparable to the sensitivity of existing detectors. The combined background emission from a potential distribution of microquasars is also modelled.

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Choudhary, Adnan, Christopher Maffeo, and Aleksei Aksimentiev. "Multi-resolution simulation of DNA transport through large synthetic nanostructures." Physical Chemistry Chemical Physics 24, no. 5 (2022): 2706–16. http://dx.doi.org/10.1039/d1cp04589j.

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Eto, Hiromune, Henri G. Franquelim, Michael Heymann, and Petra Schwille. "Membrane-coated 3D architectures for bottom-up synthetic biology." Soft Matter 17, no. 22 (2021): 5456–66. http://dx.doi.org/10.1039/d1sm00112d.

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This paper outlines a robust method to template biological membranes in 3D geometries using micron-scale 3D printing. Dynamic protein systems were reconstituted in vitro and their self-organization was observed in response to the 3D geometry.

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Deka, Siddhartha Sankar, Rituraj Gautam, Anoop Singh, Gautam Kumar, and Promod Kumar Patowari. "A Study on Synthetic Jet Actuator Diaphragm." Journal of Advanced Manufacturing Systems 14, no. 02 (April 27, 2015): 91–105. http://dx.doi.org/10.1142/s0219686715500079.

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A synthetic jet actuator (SJA) is one of the most widely used active flow control device which uses a vibrating diaphragm enclosed within a cavity to generate the fluid jet. The effectiveness of the actuator greatly depends upon the design of cavity and orifice and the diaphragm properties. A lot of emphasis is being laid on the cavity and orifice design, but very few literatures can be found dealing with the diaphragm of the SJA. Thus, in this paper a study of the SJA diaphragm actuated by piezoelectric ceramics of different geometries is being presented. Three different diaphragm materials — brass, poly-silicon and aluminum and five different geometries of the piezoelectric actuators — annular disc shaped actuator patch, annular shaped actuator, rectangular shaped actuator patch and circular disc shaped actuator patch and two cantilever arrangements are being considered. A static analysis is carried out and a comparison of the parameters which affect the performance of the SJA is done. Frequency response analysis is also carried out to obtain a better understanding of the diaphragm's structural characteristics. The results thus obtained show that an annular disc piezoelectric patch configuration shows the best behavior as compared to the other actuator configurations and is closely followed by circular disc piezoelectric patch configuration.

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Gutowski, P. R., and S. Treitel. "The generalized one‐dimensional synthetic seismogram." GEOPHYSICS 52, no. 5 (May 1987): 589–605. http://dx.doi.org/10.1190/1.1442329.

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The normal‐incidence synthetic seismogram for an elastic and horizontally stratified medium has been thoroughly studied for a relatively restricted number of source and receiver locations. Most existing treatments are concerned with the special case in which the source as well as the receiver are situated at the surface; few attempts have dealt with completely arbitrary source and receiver geometries. Here we examine arbitrary geometries with the aid of the layer matrix approach, in which upgoing and downgoing wave motion at each interface is expressed in terms of z-transform polynomials. Such an approach brings to light a number of physically important relations that the model satisfies. For example, the synthetic seismograms generally have the familiar autoregressive‐moving average (ARMA) structure for the surface‐source, surface‐receiver case. For particular combinations of reflection coefficients, however, the seismograms reduce to purely autoregressive (AR) representations. In all cases, we work out the delay properties that the respective autoregressive and moving average components must obey. The present solutions are easily reduced to a useful form for practical computation. One application of particular current interest is the simulation of vertical seismic profiling (VSP) surveys, where we have extended the theoretical treatment to include expressions for the derivatives of the seismograms with respect to the reflection coefficients. The resulting time series, which we call Jacobograms, are indicative of the sensitivity of the seismogram to the various reflection coefficients and are thus diagnostic of the model’s behavior.

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Dumont, Quentin, Valérie Cayol, and Jean-Luc Froger. "Mitigating bias in inversion of InSAR data resulting from radar viewing geometries." Geophysical Journal International 227, no. 1 (June 16, 2021): 483–95. http://dx.doi.org/10.1093/gji/ggab229.

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SUMMARY InSAR data acquired from ascending and descending orbits are often characterized by different magnitudes of the observed line-of-sight displacements, which may potentially bias inverse models. Using synthetic numerical models of dyke intrusions, we show that biased solutions are obtained when carrying out ‘conventional’ inversions where only observation and modelling errors are taken into consideration. To mitigate the impact of the relative magnitudes of the data, we propose two methods: a covariance weighting inversion and a wrapped data inversion. These methods are compared to a conventional inversion using synthetic data generated by models of dykes of known geometry. We find that the covariance weighting method allows to retrieve an initial source geometry better than the other methods. These methods are then applied to the July 2017 eruption of Piton de la Fournaise. Using a covariance weighting inversion, the difference in fit between data sets decreases from 50% to 20 % and the newly estimated source is in better agreement with the geological context.

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Halter, Dominik P., Ryan A. Klein, Michael A. Boreen, Benjamin A. Trump, Craig M. Brown, and Jeffrey R. Long. "Self-adjusting binding pockets enhance H2 and CH4 adsorption in a uranium-based metal–organic framework." Chemical Science 11, no. 26 (2020): 6709–16. http://dx.doi.org/10.1039/d0sc02394a.

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Optimizing binding pocket geometries in MOFs for ideal interaction with target molecules remains a tremendous synthetic challenge. In the new MOF U(bdc)₂, self-adjusting binding pockets flex to bind differently sized guests H₂, CH₄ and DMF.

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Solano-Perez, Jose Antonio, María-Teresa Martínez-Inglés, Jose-Maria Molina-Garcia-Pardo, Jordi Romeu, Lluis Jofre, José-Víctor Rodríguez, and Antonio Mateo-Aroca. "Linear and Circular UWB Millimeter-Wave and Terahertz Monostatic Near-Field Synthetic Aperture Imaging." Sensors 20, no. 6 (March 11, 2020): 1544. http://dx.doi.org/10.3390/s20061544.

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Millimeter-wave and terahertz frequencies offer unique characteristics to simultaneously obtain good spatial resolution and penetrability. In this paper, a robust near-field monostatic focusing technique is presented and successfully applied for the internal imaging of different penetrable geometries. These geometries and environments are related to the growing need to furnish new vehicles with radar-sensing devices that can visualize their surroundings in a clear and robust way. Sub-millimeter-wave radar sensing offers enhanced capabilities in providing information with a high level of accuracy and quality, even under adverse weather conditions. The aim of this paper was to research the capability of this radar system for imaging purposes from an analytical and experimental point of view. Two sets of measurements, using reference targets, were performed in the W band at 100 GHz (75 to 110 GHz) and terahertz band at 300 GHz (220 to 330 GHz). The results show spatial resolutions of millimeters in both the range (longitudinal) and the cross-range (transversal) dimensions for the two different imaging geometries in terms of the location of the transmitter and receiver (frontal or lateral views). The imaging quality in terms of spatial accuracy and target material parameter was investigated and optimized.

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TRIPATHI, NEETU. "A Review on Auxetic Polymeric Materials: Synthetic Methodology, Characterization and their Applications." Journal of Polymer Materials 40, no. 3-4 (March 22, 2024): 227–69. http://dx.doi.org/10.32381/jpm.2023.40.3-4.8.

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Over the last three decades, there has been considerable interest in the captivating mechanical properties displayed by auxetic materials, highlighting the advantages stemming from their distinct negative Poisson's ratio. The negative Poisson's ratio observed in auxetic polymeric materials is a result of the distinctive geometries of their unit cells. These unit cells, encompassing structures such as chiral, re-entrant, and rotating rigid configurations, are carefully engineered to collectively generate the desired auxetic behaviour. This comprehensive review article explores the field of auxetic polymeric materials, offering a detailed exploration of their geometries, fabrication methods, mechanical properties, and characterisation. The diverse applications of these materials in impact/ballistic, acoustic, automotive, biomedical, sports, shape memory, strain sensors, electromagnetic shielding, smart filters, and rehabilitation fields are thoroughly examined. Furthermore, the article emphasises the significance of auxetic behaviour in enhancing mechanical performance while shedding light on the challenges and limitations associated with large-scale fabrication of auxetic materials.

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Burlacu, Catalina Mercedes, Adrian Constantin Burlacu, and Mirela Praisler. "Physico-chemical analysis, systematic benchmarking, and toxicological aspects of the JWH aminoalkylindole class-derived synthetic JWH cannabinoids." Annals of the ”Dunarea de Jos” University of Galati Fascicle II Mathematics Physics Theoretical Mechanics 44, no. 1 (November 12, 2021): 34–45. http://dx.doi.org/10.35219/ann-ugal-math-phys-mec.2021.1.06.

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We are presenting the results obtained by computing different toxicity indices for some of the newest JWH synthetic cannabinoids, by using (Q)SAR models, ADME(T) predictions, simulations of NMR spectral techniques and other different computational dedicated software packages and forensic analytical tools. We have examined the main physical and chemical properties and evaluated the behavioral neurotoxicity and pharmacokinetic profile of 16 aminoalkylindole class-derived synthetic cannabinoids JWH as compared to the Delta-9-tetrahydrocannabinol (Δ9-THC), which was chosen as a standard compound. For this purpose, the geometries of the molecules have been optimized by using the AM1 semi-empirical quantum method. The conclusions of a comparative analysis of the toxicities of synthetic and natural cannabinoids are presented.

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Nguyen, Minh Dang, Hung-Vu Tran, Shoujun Xu, and T. Randall Lee. "Fe3O4 Nanoparticles: Structures, Synthesis, Magnetic Properties, Surface Functionalization, and Emerging Applications." Applied Sciences 11, no. 23 (November 29, 2021): 11301. http://dx.doi.org/10.3390/app112311301.

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Magnetite (Fe3O4) nanoparticles (NPs) are attractive nanomaterials in the field of material science, chemistry, and physics because of their valuable properties, such as soft ferromagnetism, half-metallicity, and biocompatibility. Various structures of Fe3O4 NPs with different sizes, geometries, and nanoarchitectures have been synthesized, and the related properties have been studied with targets in multiple fields of applications, including biomedical devices, electronic devices, environmental solutions, and energy applications. Tailoring the sizes, geometries, magnetic properties, and functionalities is an important task that determines the performance of Fe3O4 NPs in many applications. Therefore, this review focuses on the crucial aspects of Fe3O4 NPs, including structures, synthesis, magnetic properties, and strategies for functionalization, which jointly determine the application performance of various Fe3O4 NP-based systems. We first summarize the recent advances in the synthesis of magnetite NPs with different sizes, morphologies, and magnetic properties. We also highlight the importance of synthetic factors in controlling the structures and properties of NPs, such as the uniformity of sizes, morphology, surfaces, and magnetic properties. Moreover, emerging applications using Fe3O4 NPs and their functionalized nanostructures are also highlighted with a focus on applications in biomedical technologies, biosensing, environmental remedies for water treatment, and energy storage and conversion devices.

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Wood, Alan, Douglas Paton, Richard Collier, and Viki O’Connor. "Understanding regional-scale structural uncertainty: The onshore Gulf of Corinth rift as a hydrocarbon exploration analogue." Interpretation 3, no. 4 (November 1, 2015): SAC35—SAC53. http://dx.doi.org/10.1190/int-2015-0046.1.

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A major challenge when exploring for hydrocarbons in frontier areas is a lack of data coverage. Data may be restricted to regional-scale 2D seismic lines, from which assumptions of the 3D geometric configuration are drawn. Understanding the limitations and uncertainties when extrapolating 2D data into 3D space is crucial when assessing the requirements for acquiring additional data such as 3D seismic or exploration wells and of assigning geologically reasonable uncertainty ranges. The onshore Gulf of Corinth Rift provides an excellent analog for rift-scale structural uncertainty in the context of hydrocarbon exploration. We have used seismic forward modeling to explore this area of uncertainty. Synthetic seismic sections have been generated across the rift based upon fault geometries mapped in the field. Comparisons that we made of these sections with the mapped geometries allowed quantification of uncertainties encountered when extrapolating 2D data into three dimensions. We have determined how potential column heights may be severely over and underestimated due to trap integrity, spill point depth, and fault seal ambiguities directly related to fault geometric uncertainty. In addition, fault geometries and linkages also controlled the location of hanging wall synrift reservoirs. Hence, gross reservoir volumes and sediment facies distributions were also significantly influenced by how fault geometries were extrapolated along-strike from 2D to 3D.

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Vrdoljak, Višnja, Gordana Pavlović, Nadica Maltar-Strmečki, and Marina Cindrić. "Copper(ii) hydrazone complexes with different nuclearities and geometries: synthetic methods and ligand substituent effects." New Journal of Chemistry 40, no. 11 (2016): 9263–74. http://dx.doi.org/10.1039/c6nj01036a.

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The effect of synthetic methods on the nuclearity and geometry of copper(ii) complexes with aroylhydrazones was investigated. Thermally induced structural transformations of dinuclear complexes under solvent-free conditions are also described.

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Dalton, Kyle S., Thomas E. Blanford, and Daniel C. Brown. "Bistatic spatial coherence for micronavigation of a volumetric synthetic aperture sonar." Journal of the Acoustical Society of America 155, no. 3_Supplement (March 1, 2024): A348. http://dx.doi.org/10.1121/10.0027783.

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Combining multiple passes of a volumetric synthetic aperture sonar (SAS) may open new possibilities for sonar imaging, if the passes can be precisely aligned. Previous work suggests that coherence-based micronavigation is a potential approach to achieve this alignment. However, existing coherence-based techniques require assumptions that break down in many volumetric imaging geometries. This breakdown leads to a loss of coherence that has not been widely studied, and consequently, has hindered the application of micronavigation to volumetric SAS systems. This work will explore the impact of sensing range and bistatic separation on spatial coherence in downward-looking, volumetric sonar applications where the far-field assumption no longer holds. As signals transmitted from downward-looking sonars may penetrate into the sediment floor, this analysis will consider both interface and volumetric scattering. First, using both simulated and experimental sonar data, we will quantify the loss in coherence that occurs in these near-field geometries. Then, methods to regain lost coherence will be examined in an effort to enable spatial coherence-based navigation for a volumetric SAS. Finally, the work’s relevancy for ongoing efforts in acoustic navigation and repeat-pass imaging will be discussed.

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Qian, Xiaojuan, and Sangyoung Son. "THE EFFECT OF TROPICAL CYCLONES’ TRANSLATION SPEEDS AND LANDFALL ANGLES ON MAXIMUM SURGE HEIGHTS ALONG IDEALIZED COASTS." Coastal Engineering Proceedings, no. 37 (September 1, 2023): 127. http://dx.doi.org/10.9753/icce.v37.management.127.

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Global warming has known to alter the cyclonic translation speed (TS) in the past, for instance, a slowdown trend of TS in the Northwest Pacific region. Thus, the importance of TS along with landfall angle (LA) has been examined over the coast of Louisiana (Rego, 2009). Not only these cyclone’s characteristics but also the geometries that the cyclone is traveling over are found to be crucial to the development of storm surge. Meanwhile, previous studies mainly focus on one or two individual characteristics in specific sites, which made their conclusions limitedly understood. Therefore, this study aims to generalize the synthetic effects of TS, LA, and coastal geometries on a maximum surge height (MSH) along the coast through the numerical simulations of a series of idealized scenarios.

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Klinkenberg, Ernst Dieter, Hans Georg Neumann, Ulrike Bulnheim, and Joachim Rychly. "The New Art of Bone Graft Substitute Design." Key Engineering Materials 330-332 (February 2007): 959–62. http://dx.doi.org/10.4028/www.scientific.net/kem.330-332.959.

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A new method of design and manufacturing of bone graft substitutes is introduced. For the first time it is possible to prepare bone graft substitutes with a directed and controlled pore structure. Furthermore, the formation of sophisticated geometries is feasible. First in vitro investigations with cell cultures show a vital cell growing on the synthetic bone graft material. Numerous applications are possible.

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Morse, Peter F., and George F. Hildebrandt. "Ground‐roll suppression by the stackarray." GEOPHYSICS 54, no. 3 (March 1989): 290–301. http://dx.doi.org/10.1190/1.1442654.

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For 2-D common‐midpoint (CMP) seismic data acquisition, ground roll can be highly attenuated and, under ideal circumstances, virtually eliminated from the stacked data if care is taken to adjust the field geometry so that the long array formed by summing the traces of a CMP gather (i.e., the stackarray) is continuous and evenly weighted. In this paper, we use synthetic field data to quantify the improvement in signal‐to‐noise ratio that can be achieved by the stackarray and to determine if such processing steps as normal moveout (NMO) correction affect the stackarray’s effectiveness. We demonstrate that, while the beneficial effects of the stackarray are mitigated somewhat by NMO correction, source‐receiver coupling variations, and static corrections, acquisition geometries that result in a discontinuous or unevenly weighted stackarray have a much more pronounced negative effect. We also compare real field data recorded with geometries that do and do not satisfy the stackarray criterion. On the basis of both synthetic and real field data examples, we conclude that proper acquisition geometry is of prime importance in the effective implementation of the stackarray strategy.

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Moriam, Kaniz, Daisuke Sawada, Kaarlo Nieminen, Yibo Ma, Marja Rissanen, Nicole Nygren, Chamseddine Guizani, Michael Hummel, and Herbert Sixta. "Spinneret geometry modulates the mechanical properties of man-made cellulose fibers." Cellulose 28, no. 17 (October 7, 2021): 11165–81. http://dx.doi.org/10.1007/s10570-021-04220-y.

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AbstractThe production of cellulose-based textile fibers with high toughness is vital for extending the longevity and thus developing a sustainable textile industry by reducing the global burden of microplastics. This study presented strategies to improve fiber toughness by tuning spinneret geometries. Experimental studies were conducted by spinning with different spinneret geometries and measuring the mechanical and structural properties of the spun fibers. In addition, numerical simulation tools were used to better understand the effects of spinneret geometry. The altering parameters of the spinneret geometries were the capillary diameters D, the angle of the entry cone into the spinning capillary, and the ratio of capillary length to diameter L/D. The highest fiber toughness could be achieved at a capillary aspect ratio of 1 to 2. The obtained maximum fiber toughness was 93 MPa with a tensile strength of 60 cN/tex and a concomitant elongation of 16.5%. For these fiber properties, a 13 wt% solution of a high-purity pulp with higher viscosity in [DBNH][OAc] was spun into a 1.3 dtex fiber using a D100 spinneret with a capillary of 1:1 length/diameter and an entrance angle of 8°. It was noticeable that the microvoid orientations decreased almost linearly with increasing toughness of the fibers. The morphologies of the fibers were similar regardless of the spinneret geometries and the raw materials used in the spinning process. In summary, by modulating the spinneret geometries, Ioncell fibers obtained high toughness that have the potential to replace synthetic fibers.

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Daffern-Powell, Emma C., and Richard J. Parker. "Dynamical evolution of fractal structures in star-forming regions." Monthly Notices of the Royal Astronomical Society 493, no. 4 (February 28, 2020): 4925–35. http://dx.doi.org/10.1093/mnras/staa575.

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ABSTRACT The $\mathcal {Q}$-parameter is used extensively to quantify the spatial distributions of stars and gas in star-forming regions as well as older clusters and associations. It quantifies the amount of structure using the ratio of the average length of the minimum spanning tree, $\bar{m}$, to the average length within the complete graph, $\bar{s}$. The interpretation of the $\mathcal {Q}$-parameter often relies on comparing observed values of $\mathcal {Q}$, $\bar{m}$, and $\bar{s}$ to idealized synthetic geometries, where there is little or no match between the observed star-forming regions and the synthetic regions. We measure $\mathcal {Q}$, $\bar{m}$, and $\bar{s}$ over 10 Myr in N-body simulations, which are compared to IC 348, NGC 1333, and the ONC. For each star-forming region, we set up simulations that approximate their initial conditions for a combination of different virial ratios and fractal dimensions. We find that the dynamical evolution of idealized fractal geometries can account for the observed $\mathcal {Q}$, $\bar{m}$, and $\bar{s}$ values in nearby star-forming regions. In general, an initially fractal star-forming region will tend to evolve to become more smooth and centrally concentrated. However, we show that different initial conditions, as well as where the edge of the region is defined, can cause significant differences in the path that a star-forming region takes across the $\bar{m}{-}\bar{s}$ plot as it evolves. We caution that the observed $\mathcal {Q}$-parameter should not be directly compared to idealized geometries. Instead, it should be used to determine the degree to which a star-forming region is either spatially substructured or smooth and centrally concentrated.

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Shinu, Sunaina, and Chandra Prakash Dubey. "Interpretation of Isolated Magnetic Profile Using Simulated Annealing Approach." Journal of Environmental and Engineering Geophysics 27, no. 3 (September 2022): 149–64. http://dx.doi.org/10.32389/jeeg22-014.

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Understanding the magnetic anomaly in terms of the subsurface causative source plays a pivotal role in mineral exploration as well as in other geological applications. Automatic modeling of such isolated profile data is still rising, and fundamental improvements are needed in analyzing the association of subsurface rocks with the magnetic anomaly in terms of various independent model parameters. Here, we propose a MATLAB-based simulated annealing algorithm to simplify the interpretation process of magnetic anomalies. The performance of the adopted approach over various synthetic models of simple geometries like spheres, dikes, sills, and prisms is analyzed with and without contaminated noise. These geometries are widely used for some specific types of ore bodies such as iron, base metals, and mineralization such as skarns, massive sulfides, etc. Finally, two different real deposits of Chromite Ore and Uranium Ore are taken along with their magnetic anomalies to interpret their subsurface geometries in terms of model parameters. The estimated structures are verified to have a great affinity with the structures obtained in previously published works of literature. Furthermore, the present computational algorithm provides a user-friendly approach without any computational difficulties with minimum cost.

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Dalton, Kyle S., Thomas E. Blanford, and Daniel C. Brown. "Focusing late-time returns from elastic targets in bistatic collection geometries." Journal of the Acoustical Society of America 153, no. 3_supplement (March 1, 2023): A376. http://dx.doi.org/10.1121/10.0019236.

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Targets encountered during synthetic aperture sonar (SAS) surveys may exhibit elastic scattering behavior and re-radiate sound after initial interrogation. These re-radiated returns are often described as “late-time” energy, as they reach the sonar after the initial geometric returns. Range-specific focusing methods can enhance acoustic features such as late-time energy, but these methods typically make a monostatic sonar approximation that may not hold in very shallow water sensing geometries. This presentation will discuss the development of a late-time reconstruction algorithm applicable to bistatic sonar geometries. Using both simulated and experimental sonar data from monostatic and bistatic collection geometries, this work will first quantify the differences between traditionally beamformed imagery and late-time-focused imagery using common image quality metrics. Next, we will quantitatively compare the impact of collection geometry on the performance of late-time focusing algorithms. Finally, the work will describe methods that use information from a multi-static collection to compress late-time energy down to a high-contrast, spatiallycondensed point. The analysis of these signal processing strategies will focus on their potential applications to automatic target recognition.

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Yu, Xin, Scott Leaney, Jim Rutledge, and Chris Chapman. "Multievent moment-tensor inversion for ill-conditioned geometries." GEOPHYSICS 81, no. 2 (March 1, 2016): KS11—KS24. http://dx.doi.org/10.1190/geo2015-0074.1.

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Moment-tensor inversion under single monitoring well geometries becomes unstable due to the singularity of the inversion matrix. But microseismic events observed during hydraulic fracturing commonly show clusters of events with similar source mechanisms despite differences in the origin time and the magnitude. If the events with similar source mechanisms can be grouped and inverted for a single common moment tensor, the singularity can be eliminated. We have developed a normalized multievent moment-tensor inversion (NME-MTI) method, which does the MTI simultaneously for multiple events, to test the feasibility of this multievent approach. First, the scalar moment for each event was estimated using the far-field low-frequency level at each receiver. Then, the displacements measured at the receivers were normalized by the scalar moment and used to invert for the common moment tensor simultaneously for all the events in the group. We introduced a gradient search method to minimize the overall misfit by adjusting the scalar moment for each event to reduce the errors introduced by the scalar moment estimation. The algorithm was tested with a synthetic data set with four monitoring wells and a field data set with dual monitoring wells. It was proved that the NME-MTI method can retrieve the moment tensors of the event groups with data from a single monitoring well. The effects of uncertainties on the inversion were examined with data noise, scalar moment uncertainty, and event location uncertainty. The results showed that the ME-MTI result is much less sensitive to the data noise and the scalar moment uncertainty than the single-event approach. The results also determined that although the bias to the solutions increases when the event location uncertainty increases, the bias can be controlled by reducing the event location uncertainties using a more accurate location algorithm.

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Contreras, Verónica Orjuela. "Symbolic Computation of Flows in Porous Medium with Cylindrical Geometry Using Maple." Advanced Materials Research 268-270 (July 2011): 116–22. http://dx.doi.org/10.4028/www.scientific.net/amr.268-270.116.

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The study of the profiles of velocity and fluid flow rate in porous media with cylindrical geometries were made, using Maple, and the results were obtained in terms of the Bessel Functions. Some of them were the generalized forms of the Haugen-Poiseuille Law. The results could be applied to synthetic media such as zeolites. Only newtonian fluids were considered, but it’s possible to consider non newtonian fluids in the future investigations.

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Di Marzo, Marcela A. D., Pedro G. Calil, Hossein Nadali Najafabadi, Viviam Lawrence Takase, Carlos H. B. Mourão, and Jorge H. Bidinotto. "Computational Tool for Aircraft Fuel System Analysis." Aerospace 11, no. 5 (May 1, 2024): 362. http://dx.doi.org/10.3390/aerospace11050362.

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Fuel level gauging in aircraft presents a significant flight mechanics challenge due to the influence of aircraft movements on measurements. Moreover, it constitutes a multidimensional problem where various sensors distributed within the tank must converge to yield a precise and single measurement, independent of the aircraft’s attitude. Furthermore, fuel distribution across multiple tanks of irregular geometries complicates the readings even further. These issues critically impact safety and economy, as gauging errors may compromise flight security and lead to carrying excess weight. In response to these challenges, this research introduces a multi-stage project in aircraft fuel gauging systems, as a continuum of studies, where this first article presents a computational tool designed to simulate aircraft fuel sensor data readings as a function of fuel level, fuel tank geometry, sensor location, and aircraft attitude. Developed in an open-source environment, the tool aims to support the statistical inference required for accurate modeling in which synthetic data generation becomes a crucial component. A discretization procedure accurately maps fuel tank geometries and their mass properties. The tool, then, intersects these geometries with fuel-level planes and calculates each new volume. It integrates descriptive geometry to intersect these fuel planes with representative capacitive level-sensing probes and computes the sensor readings for the simulated flight conditions. The method is validated against geometries with analytical solutions. This process yields detailed fuel measurement responses for each sensor inside the tank, and for different analyzed fuel levels, providing insights into the sensors’ signals’ non-linear behavior at each analyzed aircraft attitude. The non-linear behavior is also influenced by the sensor saturation readings at 0 when above the fuel level and at 1 when submerged. The synthetic fuel sensor readings lay the baseline for a better understanding on how to compute the true fuel level from multiple sensor readings, and ultimately optimizing the amount of used sensors and their placement. The tool’s design offers significant improvements in aircraft fuel gauging accuracy, directly impacting aerostructures and instrumentation, and it is a key aspect of flight safety, fuel management, and navigation in aerospace technology.

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Gilmore, Paul, Vishnu-Baba Sundaresan, Jeremy Seidt, and Jarrod Smith. "Design and analysis of a synthetic jet actuator-based fluid atomization device." Journal of Intelligent Material Systems and Structures 28, no. 17 (January 30, 2017): 2307–16. http://dx.doi.org/10.1177/1045389x17689938.

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High-pressure nozzles and ultrasonic atomizers are the two most common devices used to generate sprays. Each of these has some disadvantages, such as controllability in high-pressure nozzles and fluid management challenges in ultrasonic devices. To overcome these limitations, a new atomization technology using a synthetic jet actuator was developed and is presented here. The work includes design and experimental analysis of both the stand-alone synthetic jet actuator and the synthetic jet-based atomization device. The synthetic jet actuator is designed using a model-based approach and characterized by measuring dynamic orifice pressure, diaphragm peak-to-peak displacement, flow rate, and power consumption. Orifice pressure reaches 296 Pa at a flow rate of 16 mL/s and 186 Pa at a flow rate of 37 mL/s for two possible synthetic jet actuator geometries, respectively. Piezoelectric diaphragm displacement reaches 50 µm with a brass substrate thickness of 0.20 mm. The synthetic jet-based atomization device is characterized with high-speed imaging and measurement of water atomization rate. It produces droplets with average sizes of 92–116 µm at maximum rates of 19–28 µL/s, depending on the geometry of the synthetic jet actuator. The outcomes of this work are principles for designing effective synthetic jet-based atomization devices, as well as system-level implementation concepts and control schemes.

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Tamilmani, Rajesh, and Emmanuel Stefanakis. "Enriched geometric simplification of linear features." GEOMATICA 71, no. 1 (March 2017): 3–19. http://dx.doi.org/10.5623/cig2017-101.

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Polyline geometries are used to represent linear features, such as roads, rivers and pipelines on maps. The generalization process results in a polyline that represents the feature either at a different resolution or different scale from the original geometries. In addition, the simplification process may result in losing the geometric properties associated with the intermediate points on the original geometries. These intermediate points can contain attributes or characteristics depending on the application domain. For example, points on the road network can contain information about accumulated length of the road, positional velocity, speed limit or accumulated gas consumption. This paper involves implementing the SELF (Semantically Enriched Line simpliFication) data structure to preserve the length attributes associated with individual points on actual linear features [Stefanakis 2015]. The number of points to be stored in the SELF structure is optimized by applying alternative compression techniques. The data structure has been implemented in PostgreSQL 9.4 [2014] with PostGIS [2016] extension using PL/pgSQL to support static and non-functional polylines. Extended experimental work has been carried out to better understand the impact of simplification on both synthetic and real (natural and artificial) linear features such as rivers and pipelines. The efficiency of SELF structure with regard to geo metric property preservation has been tested at various levels of simplification.

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Phoulady, Adrian, Hongbin Choi, Yara Suleiman, Nicholas May, Sina Shahbazmohamadi, and Pouya Tavousi. "Synthetic Data for Semantic Segmentation: A Path to Reverse Engineering in Printed Circuit Boards." Electronics 13, no. 12 (June 16, 2024): 2353. http://dx.doi.org/10.3390/electronics13122353.

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This paper presents an innovative solution to the challenge of part obsolescence in microelectronics, focusing on the semantic segmentation of PCB X-ray images using deep learning. Addressing the scarcity of annotated datasets, we developed a novel method to synthesize X-ray images of PCBs, employing virtual images with predefined geometries and inherent labeling to eliminate the need for manual annotation. Our approach involves creating realistic synthetic images that mimic actual X-ray projections, enhanced by incorporating noise profiles derived from real X-ray images. Two deep learning networks, based on the U-Net architecture with a VGG-16 backbone, were trained exclusively on these synthetic datasets to segment PCB junctions and traces. The results demonstrate the effectiveness of this synthetic data-driven approach, with the networks achieving high Jaccard indices on real PCB X-ray images. This study not only offers a scalable and cost-effective alternative for dataset generation in microelectronics but also highlights the potential of synthetic data in training models for complex image analysis tasks, suggesting broad applications in various domains where data scarcity is a concern.

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Ruiz, Andrés Castro, Krishna K. Damodaran, and Sigridur G. Suman. "Towards a selective synthetic route for cobalt amino acid complexes and their application in ring opening polymerization of rac-lactide." RSC Advances 11, no. 27 (2021): 16326–38. http://dx.doi.org/10.1039/d1ra02909f.

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Catalysts based on Co, amino acids, and 2,2-bipyridine present an attractive and economic alternative in ring opening polymerization, and possess advantageous ligand coordination properties combined with a variety of accessible oxidation states and coordination geometries.

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Lane, Aiden M., Ny T. C. Luong, Jordan C. Kelly, Martin J. Neal, Jeremiah Jamrom, Aaron J. Bloomfield, Paul A. Lummis, Thomas D. Montgomery, and Daniel T. Chase. "Synthetic Exploration of Bis(phenolate) Aza-BODIPYs and Heavier Group 13 Chelates." Molecules 27, no. 23 (November 26, 2022): 8256. http://dx.doi.org/10.3390/molecules27238256.

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A series of boron, aluminum, gallium, and indium chelates containing the underexplored bis(phenolate) aza-dipyrromethene (aza-DIPY) core were prepared. These compounds were found to possess near-infrared absorption and emission profiles in the 710 to 770 nm domain and exhibit quantum yield values up to 14%. X-ray diffraction analysis revealed that heavier group 13 bis(phenolate) aza-DIPY chelates possessed octahedral geometries with either THF or pyridine groups occupying the axial positions as opposed to the tetrahedral geometry of the boron chelate.

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Mosca, Simone, Dariush Ajami та Julius Rebek. "Recognition and sequestration of ω-fatty acids by a cavitand receptor". Proceedings of the National Academy of Sciences 112, № 36 (24 серпня 2015): 11181–86. http://dx.doi.org/10.1073/pnas.1515233112.

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One of the largest driving forces for molecular association in aqueous solution is the hydrophobic effect, and many synthetic receptors with hydrophobic interiors have been devised for molecular recognition studies in water. Attempts to create the longer, narrower cavities appropriate for long-chain fatty acids have been thwarted by solvophobic collapse of the synthetic receptors, giving structures that have no internal spaces. The collapse generally involves the stacking of aromatic panels onto themselves. We describe here the synthesis and application of a deep cavitand receptor featuring “prestacked” aromatic panels at the upper rim of the binding pocket. The cavitand remains open and readily sequesters biologically relevant long-chain molecules—unsaturated ω-3, -6, and -9 fatty acids and derivatives such as anandamide—from aqueous media. The cavitand exists in isomeric forms with different stacking geometries and n-alkanes were used to characterize the binding modes and conformational properties. Long alkyl chains are accommodated in inverted J-shaped conformations. An analogous cavitand with electron-rich aromatic walls was prepared and comparative binding experiments indicated the role of intramolecular stacking in the binding properties of these deep container molecules.

36

Rosier, Sebastian H. R., Christopher Y. S. Bull, Wai L. Woo, and G. Hilmar Gudmundsson. "Predicting ocean-induced ice-shelf melt rates using deep learning." Cryosphere 17, no. 2 (February 7, 2023): 499–518. http://dx.doi.org/10.5194/tc-17-499-2023.

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Abstract. Through their role in buttressing upstream ice flow, Antarctic ice shelves play an important part in regulating future sea-level change. Reduction in ice-shelf buttressing caused by increased ocean-induced melt along their undersides is now understood to be one of the key drivers of ice loss from the Antarctic ice sheet. However, despite the importance of this forcing mechanism, most ice-sheet simulations currently rely on simple melt parameterisations of this ocean-driven process since a fully coupled ice–ocean modelling framework is prohibitively computationally expensive. Here, we provide an alternative approach that is able to capture the greatly improved physical description of this process provided by large-scale ocean-circulation models over currently employed melt parameterisations but with trivial computational expense. This new method brings together deep learning and physical modelling to develop a deep neural network framework, MELTNET, that can emulate ocean model predictions of sub-ice-shelf melt rates. We train MELTNET on synthetic geometries, using the NEMO ocean model as a ground truth in lieu of observations to provide melt rates both for training and for evaluation of the performance of the trained network. We show that MELTNET can accurately predict melt rates for a wide range of complex synthetic geometries, with a normalised root mean squared error of 0.11 m yr−1 compared to the ocean model. MELTNET calculates melt rates several orders of magnitude faster than the ocean model and outperforms more traditional parameterisations for > 96 % of geometries tested. Furthermore, we find MELTNET's melt rate estimates show sensitivity to established physical relationships such as changes in thermal forcing and ice-shelf slope. This study demonstrates the potential for a deep learning framework to calculate melt rates with almost no computational expense, which could in the future be used in conjunction with an ice sheet model to provide predictions for large-scale ice sheet models.

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Mendez Dominguez, E., D. Henke, D. Small, and E. Meier. "HIGH RESOLUTION AIRBORNE SAR IMAGE CHANGE DETECTION IN URBAN AREAS WITH SLIGHTLY DIFFERENT ACQUISITION GEOMETRIES." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XL-3/W2 (March 10, 2015): 127–33. http://dx.doi.org/10.5194/isprsarchives-xl-3-w2-127-2015.

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Before applying change detection, high resolution SAR (Synthetic Aperture Radar) imagery benefits from advanced denoising mechanisms to preserve details and minimize speckle. We propose a change detector based on a MCA (Morphological Components Analysis) of a difference image (DI). With MCA, the data is decomposed into image features utilizing sparse representations of the image content. By introducing <i>a priori</i> knowledge of the content of the scenes, and exploiting shape information corresponding to the changes provided by MCA, we can significantly improve performance under adverse conditions, such as inconsistent acquisition geometries.

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Acharya, Joydev, Pankaj Kalita, and Vadapalli Chandrasekhar. "High-Coordinate Mononuclear Ln(III) Complexes: Synthetic Strategies and Magnetic Properties." Magnetochemistry 7, no. 1 (December 22, 2020): 1. http://dx.doi.org/10.3390/magnetochemistry7010001.

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Single-molecule magnets involving monometallic 4f complexes have been investigated extensively in last two decades to understand the factors that govern the slow magnetization relaxation behavior in these complexes and to establish a magneto-structural correlation. The prime goal in this direction is to suppress the temperature independent quantum tunneling of magnetization (QTM) effect via fine-tuning the coordination geometry/microenvironment. Among the various coordination geometries that have been pursued, complexes containing high coordination number around Ln(III) are sparse. Herein, we present a summary of the various synthetic strategies that were used for the assembly of 10- and 12-coordinated Ln(III) complexes. The magnetic properties of such complexes are also described.

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Golze, Spencer D., Stefania Porcu, Chen Zhu, Eli Sutter, Pier Carlo Ricci, Edward C. Kinzel, Robert A. Hughes, and Svetlana Neretina. "Sequential Symmetry-Breaking Events as a Synthetic Pathway for Chiral Gold Nanostructures with Spiral Geometries." Nano Letters 21, no. 7 (March 25, 2021): 2919–25. http://dx.doi.org/10.1021/acs.nanolett.0c05105.

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40

Lorenat, Jemma. "Synthetic and analytic geometries in the publications of Jakob Steiner and Julius Plücker (1827–1829)." Archive for History of Exact Sciences 70, no. 4 (February 9, 2016): 413–62. http://dx.doi.org/10.1007/s00407-015-0174-8.

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41

Gallucci, Alessio, Dmitry Znamenskiy, Yuxuan Long, Nicola Pezzotti, and Milan Petkovic. "Generating High-Resolution 3D Faces and Bodies Using VQ-VAE-2 with PixelSNAIL Networks on 2D Representations." Sensors 23, no. 3 (January 19, 2023): 1168. http://dx.doi.org/10.3390/s23031168.

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Modeling and representing 3D shapes of the human body and face is a prominent field due to its applications in the healthcare, clothes, and movie industry. In our work, we tackled the problem of 3D face and body synthesis by reducing 3D meshes to 2D image representations. We show that the face can naturally be modeled on a 2D grid. At the same time, for more challenging 3D body geometries, we proposed a novel non-bijective 3D–2D conversion method representing the 3D body mesh as a plurality of rendered projections on the 2D grid. Then, we trained a state-of-the-art vector-quantized variational autoencoder (VQ-VAE-2) to learn a latent representation of 2D images and fit a PixelSNAIL autoregressive model to sample novel synthetic meshes. We evaluated our method versus a classical one based on principal component analysis (PCA) by sampling from the empirical cumulative distribution of the PCA scores. We used the empirical distributions of two commonly used metrics, specificity and diversity, to quantitatively demonstrate that the synthetic faces generated with our method are statistically closer to real faces when compared with the PCA ones. Our experiment on the 3D body geometry requires further research to match the test set statistics but shows promising results.

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Schäfer, M., O. Gagliardini, F. Pattyn, and E. Le Meur. "Applicability of the Shallow Ice Approximation inferred from model inter-comparison using various glacier geometries." Cryosphere Discussions 2, no. 4 (July 14, 2008): 557–99. http://dx.doi.org/10.5194/tcd-2-557-2008.

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Abstract. This paper presents an inter-comparison of three different models applied to various glacier geometries. The three models are built on different approximations of the Stokes equations, from the well known Shallow Ice Approximation (SIA) to the full-Stokes (FS) solution with an intermediate higher-order (HO) model which incorporates longitudinal stresses. The studied glaciers are synthetic geometries, but two of them are constructed so as to mimic a valley glacier and a volcano glacier. For each class of glacier, the bedrock slope and/or the aspect ratio are varied. First, the models are compared in a diagnostic way for a fixed and given geometry. Here the SIA surface velocity can overestimate the FS velocity by a factor of 5 to a factor of 10. Then, the free surface is allowed to evolve and the time-dependent evolution of the glacier is studied. As a result, the difference between the models decreases, but can still be as large as a factor of 1.5 to 2. This decrease can be explained by a negative feedback for the SIA which overestimates velocities.

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Reyna-Urrutia, Víctor A., Arely M. González-González, and Raúl Rosales-Ibáñez. "Compositions and Structural Geometries of Scaffolds Used in the Regeneration of Cleft Palates: A Review of the Literature." Polymers 14, no. 3 (January 28, 2022): 547. http://dx.doi.org/10.3390/polym14030547.

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Cleft palate (CP) is one of the most common birth defects, presenting a multitude of negative impacts on the health of the patient. It also leads to increased mortality at all stages of life, economic costs and psychosocial effects. The embryological development of CP has been outlined thanks to the advances made in recent years due to biomolecular successions. The etiology is broad and combines certain environmental and genetic factors. Currently, all surgical interventions work off the principle of restoring the area of the fissure and aesthetics of the patient, making use of bone substitutes. These can involve biological products, such as a demineralized bone matrix, as well as natural–synthetic polymers, and can be supplemented with nutrients or growth factors. For this reason, the following review analyzes different biomaterials in which nutrients or biomolecules have been added to improve the bioactive properties of the tissue construct to regenerate new bone, taking into account the greatest limitations of this approach, which are its use for bone substitutes for large areas exclusively and the lack of vascularity. Bone tissue engineering is a promising field, since it favors the development of porous synthetic substitutes with the ability to promote rapid and extensive vascularization within their structures for the regeneration of the CP area.

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Rickett, James E. "Illumination‐based normalization for wave‐equation depth migration." GEOPHYSICS 68, no. 4 (July 2003): 1371–79. http://dx.doi.org/10.1190/1.1598130.

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Illumination problems caused by finite‐recording aperture and lateral velocity lensing can bias amplitudes in migration results. In this paper, I develop a normalization scheme appropriate for wave‐equation migration algorithms that compensates for irregular illumination. I generate synthetic seismic data over a reference reflectivity model, using the adjoint of wave‐equation shot‐profile migration as the forward modeling operator. I then migrate the synthetic data with the same shot‐profile algorithm. The ratio between the synthetic migration result and the initial reference model is a measure of seismic illumination. Dividing the true data migration result by this illumination function mitigates the illumination problems. The methodology can take into account reflector dip as well as both shot and receiver geometries, and, because it is based on wave‐equation migration, it naturally models the finite‐frequency effects of wave propagation. The reference model should be as close to the true model as possible; good choices include the migrated image, or a synthetic image with a single known dip that corresponds to the expected dip of a reflector of interest. Computational shortcuts allow the illumination functions to be computed at about the cost of a single migration. Results indicate that normalization can significantly reduce amplitude distortions due to irregular subsurface illumination.

45

Zhu, Tianfei, and Larry D. Brown. "Two‐dimensional velocity inversion and synthetic seismogram computation." GEOPHYSICS 52, no. 1 (January 1987): 37–50. http://dx.doi.org/10.1190/1.1442239.

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A traveltime inversion scheme has been developed to estimate velocity and interface geometries of two‐dimensional media from deep reflection data. The velocity structure is represented by finite elements, and the inversion is formulated as an iterative, constrained, linear least‐squares problem which can be solved by either the singular value truncation method or the Levenberg‐Marquardt method. The damping factor of the Levenberg‐Marquardt method is chosen by the model‐trust region approach. The traveltimes and derivative matrix required to solve the least‐squares problem are computed by ray tracing. To aid seismic interpretation, we also include in the inversion scheme a fast algorithm based on asymptotic ray theory for calculating synthetic seismograms from the derived velocity model. Numerical tests indicate that the inversion scheme is effective, and that the accuracy of inversion results depends upon both noise in the data and the aperture of recording used in data acquisition. Two real examples demonstrate that the new inversion scheme produces velocity models fitting the data better than those estimated by other approaches.

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Singh, Pankaj, Prabodh Pandey, Shivam Shukla, Naren Naik, and Asima Pradhan. "Modelling, Design and Validation of Spatially Resolved Reflectance Based Fiber Optic Probe for Epithelial Precancer Diagnostics." Applied Sciences 10, no. 24 (December 10, 2020): 8836. http://dx.doi.org/10.3390/app10248836.

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Fiber-optic probes are imperative for in-vivo diagnosis of cancer. Depending on the access to a diseased organ and the mutations one aims to sense, the probe designs vary. We carry out a detailed numerical study of the efficacy of the common probe geometries for epithelial cancer characterization based on spatially resolved reflectance data. As per the outcomes of this comparative study, a probe has been manufactured and using Monte Carlo look up table based inversion scheme, the absorption and scattering coefficients of the epithelium mimicking top layer have been recovered from noisy synthetic as well as experimental data.

47

Keating, Pierre. "Improved use of the local wavenumber in potential-field interpretation." GEOPHYSICS 74, no. 6 (November 2009): L75—L85. http://dx.doi.org/10.1190/1.3242270.

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Fast interpretation of potential field data (magnetic data are a typical example) often uses simple geometries to describe a complex geologic reality. Many of these techniques assume that the potential field arising from the source body is homogeneous. The degree of homogeneity of a source is characteristic of its geometry. However, very few source geometries are known to generate a homogeneous field. The contact, thin sheet, horizontal cylinder, pole, and dipole all cause a homogeneous magnetic field. More complex geometries such as the thick dike or rectangular prism do not. Therefore, a major problem is to check for the validity of the homogeneity hypothesis when these types of interpretation techniques are used. The local wavenumber of a potential field calculated at a series of increasing heights above the measurement datum can be used to directly compute the depth to a source and its degree of homogeneity. In addition, the vertical derivative of the local wavenumber can provide an estimate of the depth to sources without knowledge of their degree of homogeneity. The proposed technique also allows us to test if the source is homogeneous or not, and it applies to any type of potential field data. The technique breaks down on synthetic magnetic data when anomalous sources are closer than about four times their depths. This behavior is expected from interpretation techniques that use upward continuation. The technique can be applied to profile and gridded data. Its main advantage is that it allows testing the homogeneity hypothesis and therefore the validity of the interpretation.

48

Mohammadi, Mohammad Ebrahim, Richard L. Wood, and Christine E. Wittich. "Non-Temporal Point Cloud Analysis for Surface Damage in Civil Structures." ISPRS International Journal of Geo-Information 8, no. 12 (November 26, 2019): 527. http://dx.doi.org/10.3390/ijgi8120527.

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Assessment and evaluation of damage in civil infrastructure is most often conducted visually, despite its subjectivity and qualitative nature in locating and verifying damaged areas. This study aims to present a new workflow to analyze non-temporal point clouds to objectively identify surface damage, defects, cracks, and other anomalies based solely on geometric surface descriptors that are irrespective of point clouds’ underlying geometry. Non-temporal, in this case, refers to a single dataset, which is not relying on a change detection approach. The developed method utilizes vertex normal, surface variation, and curvature as three distinct surface descriptors to locate the likely damaged areas. Two synthetic datasets with planar and cylindrical geometries with known ground truth damage were created and used to test the developed workflow. In addition, the developed method was further validated on three real-world point cloud datasets using lidar and structure-from-motion techniques, which represented different underlying geometries and exhibited varying severity and mechanisms of damage. The analysis of the synthetic datasets demonstrated the robustness of the proposed damage detection method to classify vertices as surface damage with high recall and precision rates and a low false-positive rate. The real-world datasets illustrated the scalability of the damage detection method and its ability to classify areas as damaged and undamaged at the centimeter level. Moreover, the output classification of the damage detection method automatically bins the damaged vertices into different confidence intervals for further classification of detected likely damaged areas. Moving forward, the presented workflow can be used to bolster structural inspections by reducing subjectivity, enhancing reliability, and improving quantification in surface-evident damage.

49

Azmy, Y. Y., and Edward W. Larsen. "Fourier Analysis of the Diffusion Synthetic Acceleration Method for Weighted Diamond-Differencing Schemes in Cartesian Geometries." Nuclear Science and Engineering 95, no. 2 (February 1987): 106–15. http://dx.doi.org/10.13182/nse87-a20421.

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Soberanes, Yedith, Rosa Elena Navarro, Motomichi Inoue, Enrique F. Velázquez-Contreras, Melissa Beltran Torres, Gustavo Lugo, Rogerio R. Sotelo-Mundo, and Alex J. Salazar-Medina. "Syntheses, Characterization, and Antioxidant Evaluation of Cu2+, Mn2+, and Fe3+ Complexes with a 14 Membered EDTA-Derived Macrocycle." Molecules 24, no. 19 (October 1, 2019): 3556. http://dx.doi.org/10.3390/molecules24193556.

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The Cu2+, Mn2+, and Fe3+ complexes of a 14 membered macrocycle were synthesized and their antioxidant capacities were evaluated against ABTS and DPPH radicals, with the objective of collecting insights into the biomimetic role of the central metal ions. The macrocycle, abbreviated as H2L14, is a derivative of EDTA cyclized with 1,4-diamine, and the moderately flexible macrocyclic frame permits the formation of [ML14·H2O] chelates with octahedral coordination geometries common among the metal ions. The metal complexes were characterized by electrospray-ionization mass spectrometry, Fourier transform infrared spectroscopy, and Raman and X-ray photoelectron spectroscopic methods, as well as thermogravimetric analysis; the octahedral coordination geometries with water coordination were optimized by DFT calculations. The antioxidant assays showed that [FeL14·H2O]+ was able to scavenge synthetic radicals with moderate capacity, whereas the other metal chelates did not show significant activity. The Raman spectrum of DPPH in solution suggests that interaction was operative between the Fe3+ chelate and the radical so as to cause scavenging capability. The nature of the central metal ions is a controlling factor for antioxidant capacity, as every metal chelate carries the same coordination geometry.

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