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Статті в журналах з теми "TKD on-axis":
1
Shen, Yitian, Jingchao Xu, Yongsheng Zhang, Yongzhe Wang, Jimei Zhang, Baojun Yu, Yi Zeng, and Hong Miao. "Spatial Resolutions of On-Axis and Off-Axis Transmission Kikuchi Diffraction Methods." Applied Sciences 9, no. 21 (October 23, 2019): 4478. http://dx.doi.org/10.3390/app9214478.
Анотація:
Spatial resolution is one of the key factors in orientation microscopy, as it determines the accuracy of grain size investigation and phase identification. We determined the spatial resolutions of on-axis and off-axis transmission Kikuchi diffraction (TKD) methods by calculating correlation coefficients using only the effective parts of on-axis and off-axis transmission Kikuchi patterns. During the calculation, we used average filtering to evaluate the spatial resolution more accurately. The spatial resolutions of both on-axis and off-axis TKD methods were determined in the same scanning electron microscope at different accelerating voltages and specimen thicknesses. The spatial resolution of the on-axis TKD was higher than that of the off-axis TKD at the same parameters. Furthermore, with an increase in accelerating voltage or a decrease in specimen thickness, the spatial resolutions of the two configurations could be significantly improved, from tens of nanometers to below 10 nm. At a voltage of 30 kV and sample thickness of 74 nm, both on-axis and off-axis TKD methods exhibited the highest resolutions of 6.2 and 9.7 nm, respectively.
2
Brodu, Etienne, Emmanuel Bouzy, Jean-Jacques Fundenberger, Julien Guyon, Antoine Guitton, and Yudong Zhang. "On-axis TKD for orientation mapping of nanocrystalline materials in SEM." Materials Characterization 130 (August 2017): 92–96. http://dx.doi.org/10.1016/j.matchar.2017.05.036.
3
Ernould, Clément, Benoît Beausir, Jean-Jacques Fundenberger, Vincent Taupin, and Emmanuel Bouzy. "Characterization at high spatial and angular resolutions of deformed nanostructures by on-axis HR-TKD." Scripta Materialia 185 (August 2020): 30–35. http://dx.doi.org/10.1016/j.scriptamat.2020.04.005.
4
Ernould, Clément, Benoît Beausir, Jean-Jacques Fundenberger, Vincent Taupin, and Emmanuel Bouzy. "Global DIC approach guided by a cross-correlation based initial guess for HR-EBSD and on-axis HR-TKD." Acta Materialia 191 (June 2020): 131–48. http://dx.doi.org/10.1016/j.actamat.2020.03.026.
5
Crouzier, Loïc, Nicolas Feltin, Alexandra Delvallée, Francesco Pellegrino, Valter Maurino, Grzegorz Cios, Tomasz Tokarski, et al. "Correlative Analysis of the Dimensional Properties of Bipyramidal Titania Nanoparticles by Complementing Electron Microscopy with Other Methods." Nanomaterials 11, no. 12 (December 10, 2021): 3359. http://dx.doi.org/10.3390/nano11123359.
Анотація:
In this paper, the accurate determination of the size and size distribution of bipyramidal anatase nanoparticles (NPs) after deposition as single particles on a silicon substrate by correlative Scanning Electron Microscopy (SEM) with Atomic Force Microscopy (AFM) analysis is described as a new measurement procedure for metrological purposes. The knowledge of the exact orientation of the NPs is a crucial step in extracting the real 3D dimensions of the particles. Two approaches are proposed to determine the geometrical orientation of individual nano-bipyramides: (i) AFM profiling along the long bipyramid axis and (ii) stage tilting followed by SEM imaging. Furthermore, a recently developed method, Transmission Kikuchi Diffraction (TKD), which needs preparation of the crystalline NPs on electron-transparent substrates such as TEM grids, has been tested with respect to its capability of identifying the geometrical orientation of the individual NPs. With the NPs prepared homogeneously on a TEM grid, the transmission mode in a SEM, i.e., STEM-in-SEM (or T-SEM), can be also applied to extract accurate projection dimensions of the nanoparticles from the same sample area as that analysed by SEM, TKD and possibly AFM. Finally, Small Angle X-ray Scattering (SAXS) can be used as an ensemble technique able to measure the NPs in liquid suspension and, with ab-initio knowledge of the NP shape from the descriptive imaging techniques, to provide traceable NP size distribution and particle concentration.
6
Wollschläger, Nicole, Ines Häusler, Erik Ortel, Vasile-Dan Hodoroaba, Laurie Palasse, and Kai Dirscherl. "Characterization of Porous, TiO2 Nanoparticle Films Using On-Axis TKD in SEM -a New Nano-Analysis Tool for a Large-Scale Application." Microscopy and Microanalysis 23, S1 (July 2017): 542–43. http://dx.doi.org/10.1017/s1431927617003397.
7
Jiang, Qing, Yao Chen, Qi Shuai, Fulin Liu, Lang Li, Chao He, Hong Zhang, Chong Wang, Yongjie Liu, and Qingyuan Wang. "Fatigue-Induced HCP-to-FCC Phase Transformation Resulting in Two FCC-Zr Variants in Pure Zirconium." Materials 16, no. 18 (September 14, 2023): 6215. http://dx.doi.org/10.3390/ma16186215.
Анотація:
This study utilized transmission electron microscopy (TEM) and on-axis transmission Kikuchi diffraction (TKD) to investigate the fatigue-induced HCP-to-FCC phase transformation in industrial pure zirconium under a stress ratio of R = 0.1. The results show that fatigue damages result from phase deformations during cyclic loadings. The fatigue-induced FCC-Zr phases exhibit a B-type orientation relationship with the HCP-Zr matrix. Notedly, due to the different growth directions of Shockley partial dislocations relative to nucleation points, there are two FCC-Zr variants after the HCP-to-FCC phase transformation. The content of these two variants accounts for 65% and 35% of the total FCC-Zr, respectively, appearing as lamellae morphology embedded parallelly within the matrix. The distribution of the two variants includes isolated distribution and adjacent distribution. For the adjacent distribution, a twinning relationship is observed between the two variants. Meanwhile, as an intermediate transition stage of the HCP-to-FCC phase transformation, stacking faults are observed at the boundaries of the FCC-Zr lamellae. These findings offer insights into the microstructural features and formation mechanisms of fatigue-induced HCP-to-FCC phase transformation.
8
Chia, Joanne S. J., Jennifer L. McRae, Peter J. Cowan, and Karen M. Dwyer. "The CD39-Adenosinergic Axis in the Pathogenesis of Immune and Nonimmune Diabetes." Journal of Biomedicine and Biotechnology 2012 (2012): 1–7. http://dx.doi.org/10.1155/2012/320495.
Анотація:
Diabetes mellitus encompasses two distinct disease processes: autoimmune Type 1 (T1D) and nonimmune Type 2 (T2D) diabetes. Despite the disparate aetiologies, the disease phenotype of hyperglycemia and the associated complications are similar. In this paper, we discuss the role of the CD39-adenosinergic axis in the pathogenesis of both T1D and T2D, with particular emphasis on the role of CD39 and CD73.
9
Klemetti, Miira M., Sruthi Alahari, Martin Post, and Isabella Caniggia. "Distinct Changes in Placental Ceramide Metabolism Characterize Type 1 and 2 Diabetic Pregnancies with Fetal Macrosomia or Preeclampsia." Biomedicines 11, no. 3 (March 17, 2023): 932. http://dx.doi.org/10.3390/biomedicines11030932.
Анотація:
Disturbances of lipid metabolism are typical in diabetes. Our objective was to characterize and compare placental sphingolipid metabolism in type 1 (T1D) and 2 (T2D) diabetic pregnancies and in non-diabetic controls. Placental samples from T1D, T2D, and control pregnancies were processed for sphingolipid analysis using tandem mass spectrometry. Western blotting, enzyme activity, and immunofluorescence analyses were used to study sphingolipid regulatory enzymes. Placental ceramide levels were lower in T1D and T2D compared to controls, which was associated with an upregulation of the ceramide degrading enzyme acid ceramidase (ASAH1). Increased placental ceramide content was found in T1D complicated by preeclampsia. Similarly, elevated ceramides were observed in T1D and T2D pregnancies with poor glycemic control. The protein levels and activity of sphingosine kinases (SPHK) that produce sphingoid-1-phosphates (S1P) were highest in T2D. Furthermore, SPHK levels were upregulated in T1D and T2D pregnancies with fetal macrosomia. In vitro experiments using trophoblastic JEG3 cells demonstrated increased SPHK expression and activity following glucose and insulin treatments. Specific changes in the placental sphingolipidome characterize T1D and T2D placentae depending on the type of diabetes and feto-maternal complications. Increased exposure to insulin and glucose is a plausible contributor to the upregulation of the SPHK-S1P-axis in diabetic placentae.
10
Apelfröjd, S., and S. Eriksson. "Evaluation of Harmonic Content from a Tap Transformer Based Grid Connection System for Wind Power." Journal of Renewable Energy 2013 (2013): 1–8. http://dx.doi.org/10.1155/2013/190573.
Анотація:
Simulations done in MATLAB/Simulink together with experiments conducted at the Ångströms laboratory are used to evaluate and discuss the total harmonic distortion (THD) and total demand distortion (TDD) of a tap transformer based grid connection system. The grid connection topology can be used with different turbine and generator topologies and is here applied on a vertical axis wind turbine (VAWT) with a permanent magnet synchronous generator (PMSG) and its operational scheme. The full variable-speed wind conversion system consists of a diode rectifier, DC link, IGBT inverter, LCL-filter, and tap transformer. The full variable-speed operation is enabled by the use of the different step-up ratios of the tap transformer. In the laboratory study, a full experimental setup of the system was used, a clone of the on-site PMSG driven by a motor was used, and the grid was replaced with a resistive load. With a resistive load, grid harmonics and possible unbalances are removed. The results show a TDD and THD below 5% for the full operating range and harmonic values within the limits set up by IEEE-519. Furthermore, a change in tap, going to a lower step-up ratio, results in a reduction in both THD and TDD for the same output power.
Дисертації з теми "TKD on-axis":
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Ernould, Clément. "Développement et application d’une méthode à haute résolution angulaire pour la mesure des gradients d’orientation et des déformations élastiques par microscopie électronique à balayage." Electronic Thesis or Diss., Université de Lorraine, 2020. http://www.theses.fr/2020LORR0225.
Анотація:
La compréhension des mécanismes de déformation dans les matériaux cristallins passe par la caractérisation fine des microstructures. Dans le cadre de la microscopie électronique à balayage, la mesure précise des gradients d’orientation et des déformations élastiques du cristal est l’objectif des méthodes dites à haute résolution angulaire. Pour cela, elles emploient des techniques de corrélation d’images numériques afin de recaler les clichés de diffraction électronique. Cette thèse propose une méthode de recalage originale. Le champ de déplacement à l’échelle du scintillateur est décrit par une homographie linéaire. Il s’agit d’une transformation géométrique largement utilisée en vision par ordinateur pour modéliser les projections. L’homographie entre deux clichés est mesurée à partir d’une grande et unique région d’intérêt en utilisant un algorithme de Gauss-Newton par composition inverse numériquement efficace. Une correction des distorsions optiques causées par les lentilles de la caméra lui est intégrée et sa convergence est assurée par un pré-recalage des clichés. Ce dernier repose sur des algorithmes de corrélation croisée globale basés sur les transformées de Fourier-Mellin et de Fourier. Il permet de rendre compte des rotations allant jusqu’à une dizaine de degrés avec une précision comprise typiquement entre 0,1 et 0,5°. La détermination de l’homographie est indépendante de la géométrie de projection. Cette dernière n’est considérée qu’à l’issue du recalage pour déduire analytiquement les rotations et les déformations élastiques. La méthode est validée numériquement sur des clichés simulés distordus optiquement, désorientés jusqu’à 14° et présentant des déformations élastiques équivalentes jusqu’à 5×10⁻². Cette étude montre que la mesure précise de déformations élastiques comprises entre 1×10⁻⁴ et 2×10⁻³ nécessite de corriger la distorsion optique radiale, même lorsque la désorientation est faible. Finalement, la méthode est appliquée à des clichés acquis par diffraction des électrons rétrodiffusés (EBSD) et en transmission en utilisant la nouvelle configuration TKD on-axis (transmission Kikuchi diffraction). Des métaux polycristallins déformés plastiquement ainsi que des semi-conducteurs sont caractérisés. La méthode retranscrit des détails fins de la microstructure d’un acier martensitique trempé et revenu et d’un acier sans interstitiels déformé de 15% en traction, malgré la détérioration du contraste de diffraction induit par la déformation plastique. Les structures de déformation sont également analysées dans de l’aluminium nanostructuré obtenu par déformation plastique sévère grâce au couplage de la méthode de recalage et de la configuration TKD on-axis. Ce couplage permet d’atteindre simultanément une haute résolution spatiale (3 à 10 nm) et une haute résolution angulaire (0,01 à 0,05°). Des cartes de déformation élastiques sont obtenues à l’échelle de quelques nanomètres dans une lame mince de SiGe et les densités de dislocations dans un monocristal de GaN sont déterminées avec une résolution voisine de 2,5×10⁻³ µm⁻¹ (soit 8×10¹² m⁻²)Understanding the deformation mechanisms in crystalline materials requires a fine characterization of microstructures. The precise measurement of lattice rotations and elastic strains in the scanning electron microscope is the aim of the so-called high-angular resolution methods. For this purpose, digital image correlation techniques are used in order to register electron diffraction patterns. In this thesis, an original registration approach is proposed. The displacement field across the whole scintillator is modelled by a linear homography. Such a shape function is often met is the field of computer vision to describe projective transformations. The homography between two patterns is measured from a single and large region of interest using a numerically efficient inverse-compositional Gauss-Newton algorithm. It integrates a correction of optical distortions caused by camera lenses and its convergence is ensured by a pre-alignment step of the patterns. The latter relies on global cross-correlation algorithms based on Fourier-Mellin and Fourier transforms. It fairly accounts for rotations up to approximately ten degrees with an accuracy typically between 0.1 and 0.5°. The homography is measured independently from the projection geometry, which is only considered afterwards to analytically deduce the rotations and elastic strains. The proposed method is validated numerically from simulated and optically distorted patterns showing disorientations up to 14° in the presence of elastic strains up to 5×10⁻². The accurate measurement of elastic strains between 1×10⁻⁴ and 2×10⁻³ requires a correction of radial distortion effects, even when the disorientation angle is small. Finally, the method is applied to patterns acquired by means of electron backscatter diffraction (EBSD) and in transmission using the new on-axis transmission Kikuchi diffraction (TKD) configuration. Plastically deformed polycrystalline metals as well as semiconductors are characterized. The method highlights fine details of the microstructure of a quenched and tempered martensitic steel and of an interstitial free steel deformed by 15% in tension, although plastic deformation deteriorates the diffraction contrast. The deformation structures in a nanostructured aluminium obtained by severe plastic deformation are also analysed by coupling the image registration method to the on-axis TKD configuration. This coupling allows a high spatial resolution (3 to 10 nm) and a high angular resolution (0.01 to 0.05°) to be reached simultaneously. Elastic strain maps are obtained at the nanoscale in a SiGe thin foil. The geometrically necessary dislocation densities in a GaN single crystal are mapped with a resolution of about 2.5×10⁻³ µm⁻¹ (i.e. 8×10¹² m⁻²)
2
Comstock, John E. "Vertical Axis Rotation in the Silurian Hills: A Cenozoic Overprint on the Mesozoic U.S. Cordilleran Magmatic Arc." ScholarWorks@UNO, 1997. http://scholarworks.uno.edu/td/2241.
Анотація:
New, detailed field work in the Silurian hills, southeast of Death Valley, reveals a pattern of a complex Cenozoic brittle fault overprint of rocks containing evidence of at least three episodes of Mesozoic thermal-ductile deformation. The Cenozoic brittle fault overprint of rocks containing evidence of at least three episodes of Mesozoic thermal-ductile formation. The Cenozoic faulting consists of five distinct sets of structures ordered by cross cutting relationships. The oldest, BF1, are fragments of reverse faults trending NW and dipping 45-60 SW. BF2 consist of NW trending, en echelon, sinistral strike-slip faults. BF3 is a conjugate set of N-NE trending high-angle normal faults with 100's m offset. BF4 is a complex array of conjugate strike-slip and normal faults. NNW trending dextral and NNE trending sinistral faults offset and are offset by N and NW trending conjugate sets of high-angle normal faults. The younges set, BF5, are low-angle normal faults with no consistent basal surface or transport direction. These are interpreted to be right lateral, strike-slip extension (dextral transtension, BF4 & BF5) preceded by right lateral, vertical axis rotation, and strike-slip shortening (dextral transrotation and transpression, BF2 & BF3), all related to the interaction of the Garlock fault and northwest trending dextral shear. 30° of clockwise vertical axis rotation is inferred to have affected the Silurian Hills since the Middle Miocene as the result of BF2 & BF3 deformation.
The Mesozoic deformations are; 1, a greenschist facies, low-strain but tightly folded N vergent, crystalline basement through Pahrump Group section; 2, a greenschist facies, high-strain, 100's m thick, mylonite zone with stretching lineations trending NE-SW; and 3, an upper amphibolite facies (high T, low P), high-strain E-W trending, S plunging Pahrump Group section, syntectonically intruded by multiple igneous phases U-Pb dated from 177 Ma to 97 Ma. The two Pahrump Group sections are interpreted to form as the result of NW directed backthrusting in the hinterland of the Sevier orogeny and were juxtaposed by NNW normal, extensional transport along the mylonite zone after crustal thickening. K-Ar biotite cooling ages suggest the mylonite zone developed during the Late Cretaceous to Eocene time.
Finally, the protolith of the tectonostratigraphic Riggs Formation to be two formations of the Pahrump Group, the Crystal Spring and Beck Spring Formations.
3
Low, Benjamin. "Design of a 3 axis wear testing device to evaluate the effect of slide to roll ratio on ultra high molecular weight polyethylene wear in total knee replacements." Thesis, University of Canterbury. Mechanical Engineering, 2005. http://hdl.handle.net/10092/1105.
Анотація:
Multidirectional motion occurs in total knee replacements (TKR), is a major factor in ultra high molecular weight polyethylene (UHMWPE) wear and is a requirement for wear tester and simulators. There are three ways the femoral component can move relative to the tibial component; sliding, rolling and gliding and these are defined by the slide to roll ratio. Previous wear tester research has investigated the effects of multidirectional motion and slide to roll ratio, individually but not combined. The project aim was to design a machine that combined multidirectional motion with variable slide to roll ratio. A three station wear testing machine was designed and built featuring flexion extension, variable anterior posterior translation, variable internal external rotation and a 2KN load per station. The TKR was simplified to a cylinder on flat. Lubrication was 25% bovine serum and each station had its own recirculation system. A million cycle validation test was successfully carried out on non-irradiated UHMWPE samples using a slide to roll ratio of 1 : 0.5 and the mean wear rate was 14.7mg/10^6 cycles. Polished areas and scratches from 3rd body abrasion were observed. Magnification revealed a fine ripple pattern with a 1-2 micron periodicity. Ripples were randomly oriented, perpendicular to the primary direction of motion and a small number were running parallel to the primary direction of motion, indicative of rolling motion. The results from the validation study show that the knee joint wear tester is capable of producing wear rates and wear mechanisms similar to those observed in other wear testers and knee joint simulators and has met the aim of the project.
Частини книг з теми "TKD on-axis":
1
Hadjkacem, Sahar, Mohamed Ali Jemni, and Zied Driss. "Turbine Swirling Device Effect on LPG-H2 Engine In-Cylinder Flow Motion at Intake Stroke." In Mechanical Engineering Technologies and Applications: Volume 3, 44–53. BENTHAM SCIENCE PUBLISHERS, 2023. http://dx.doi.org/10.2174/9789815179279123030006.
Анотація:
The main issue of internal combustion (IC) engines is efficiency. Engine inlet systems should be carefully designed to provide an optimum flow to the cylinder. Inlet manifold design is one of the ways to increase efficiency. This study focuses on improving the inlet system of an LPG-H2 fueled engine by adding a static inclined blade turbine. It is a horizontal rotational axis turbine with four blades evenly distributed with an angle of inclination of 35°. Computational Fluid Dynamics (CFD) simulations are used in order to capture the in-cylinder flow motion and its influence on the flow characteristics. The method is assessed by application to flow calculations in the intake manifold for 3000 rpm engine speed. The percentage of supplied Hydrogen with LPG is equal to 20% in volume. The simulation results of in-cylinder turbulence kinetic energy (TKE), velocity and swirl motion were presented and discussed. Numerical results reveal significant improvements in the in-cylinder flow velocity, in-cylinder swirl motion and turbulent characteristics using an inlet system with a static swirling turbine (SST). Hence, this research found that by using a static turbine, we can improve the in-cylinder flow characteristics of the CI engine running with the LPG-20%H2 blend.
2
Rocha, Lizandra Viana Maurat da, Paulo Sergio Rangel Cruz da Silva, and Maria Inês Bruno Tavares. "Comparative Study Of Poly (Butylene Adipate Co-Terephthalate) Nanocomposites With Zinc And Molybdenum Oxides." In COLLECTION OF INTERNATIONAL TOPICS IN HEALTH SCIENCE- V1. Seven Editora, 2023. http://dx.doi.org/10.56238/colleinternhealthscienv1-122.
Анотація:
studies on nanocomposites of biodegradable polymers such as polybutylene adipate co-terephthalate (PBAT) are justified. This polymer is certified for composting; it is printable, suitable for food contact, water resistant, and performs similarly to polyethylene[1, 2] . Metal oxide nanoparticles (NPs) such as MoO3 and ZnO are potential fillers to, in addition to improving mechanical properties, confer antimicrobial, anti-UV activity and modulate the biodegradability of polymer matrices such as that of PBAT[3, 4, 5] . The effects of different concentrations of ZnONPs were observed and compared to MoO3 NPs, whose relevant properties still lack further study. In this work, seven films prepared by casting with CHCl solvent evaporation were studied3 . The tags PBAT, Z1, Z3, Z5, M1, M3 and M5 correspond to the pure polymer samples and their combinations with 0.1; 0.3 and 0.5 % of zinc and molybdenum oxide NPs, by mass, respectively. The Fourier transform infrared spectroscopy (FTIR) ratified the total removal of the solvent and the maintenance of the bands of the main functional groups of the polymeric matrix, even after the incorporation of the NPS. In the thermogravimetric analysis (TGA), only one degradation event was observed for all samples; in M1 and especially in M3 the thermal resistance increased, while, with the addition of zinc oxide, especially in Z5 and Z3, this property was reduced. There was no expressive change in the degradation onset temperature (Tonset ) of M5 in relation to PBAT, suggesting that this concentration of MoO₃ cannot promote increment in the thermal property of this matrix. The X-ray diffraction (XRD) results of M1 and M3 suggested a better dispersion than M5, the only composite in which there was no increase in the degree of crystallinity in relation to pure PBAT, indicating possible agglomeration. In time domain nuclear magnetic resonance (TD-NMR) analysis, the curves of M3 present a narrower base, indicating greater homogeneity and especially good dispersion in this system, corroborating the other analyses. The reduced return time of the magnetization to the longitudinal axis (T1 H) of M5 and the increased molecular mobility of this system were associated with the crystalline rearrangement. When measuring the water activity (aw ) thinking in the application of these films as active packaging, Z3 and M1 stood out, with lower propensity to microbiological attack, and a linear trend (R² > 0.9) was observed for this property with the incorporation of molybdenum nanotrioxide in poly(butylene adipate co-terephthalate). The worst aw data were observed in Z1, with M3 and M5 being similar to Z5. Still, all observed aw values were below the recommended value for food packaging, 0.7 (the value at which susceptibility becomes most relevant). Thus, it was shown to be possible to incorporate zinc and molybdenum metal oxides in the PBAT matrix, via casting, with good distribution and better dispersion of fillers in the range of 0.3% by mass. Moreover, it was observed that different types and proportions of particles resulted in different effects on the microstructure of the matrix (thermal resistance, crystallinity, molecular mobility and water activity), without causing interaction capable of affecting the molecular composition of the material, at levels detectable by FTIR-ATR.
Тези доповідей конференцій з теми "TKD on-axis":
1
Goran, Daniel, Thomas Schwager, and Alice Bastos DaSilva Fanta. "Recent Developments for the Characterization of Crystals and Defects at the Nanoscale using On-Axis TKD in SEM." In ISTFA 2021. ASM International, 2021. http://dx.doi.org/10.31399/asm.cp.istfa2021p0217.
Анотація:
Abstract In this paper, we describe the technique of on-axis transmission Kikuchi diffraction (TKD) in a scanning electron microscope and demonstrate its use in characterizing nanoscale crystal structures and defects in semiconductor materials and devices. We explain how we modified hardware and software to achieve an effective spatial resolution of 2 nm during orientation mapping without decreasing acquisition speed, indexing quality, and other performance parameters. The paper includes illustrations comparing sample-detector geometries for conventional EBSD, TKD, and on-axis TKD. It also presents examples of the types of images that can be obtained using on-axis TKD, including raw crystal orientation maps, diffraction patterns, pattern quality maps, time-resolved orientation maps showing microstructure evolution, and a sparse sample map showing the distribution of quantum dots on an electron transparent support film.
2
Ernould, Clément. "A novel High-angular Resolution “on-axis” Transmission Kikuchi Diffraction (HR-TKD) technique for the fine characterization of deformed nanostructures in the SEM." In European Microscopy Congress 2020. Royal Microscopical Society, 2021. http://dx.doi.org/10.22443/rms.emc2020.230.
3
Lowdon, Ross, Sjoerd Brands, Mahmoud ElGizawy, and Sheldon Rawlins. "Rotating 6 Axis Survey Measurement and it's Effect on True Vertical Depth Accuracy, a Study of Sag Correction and Misalignment While Drilling." In SPE Annual Technical Conference and Exhibition. SPE, 2022. http://dx.doi.org/10.2118/210184-ms.
Анотація:
Abstract Definitive dynamic 6 axis surveys provide continuous MWD quality measurement while drilling. This poses a challenge in terms of misalignment (relative to the borehole) correction when compared to traditional static survey measurements where misalignments are well understood and can be easily compensated for. The increased frequency of surveys allows for the possibility of significant systematic TVD errors if a static misalignment (SAG) error is applied unilaterally to the definitive dynamic surveys. This paper outlines how we can measure misalignment in definitive dynamic surveys, what the magnitude of those misalignments are and their impact on a wells TVD. The misalignment of Definitive Dynamic Survey measurement with respect to the borehole is a complex problem, as the BHA is under dynamic load and rotation as measurements are being made. As such a dynamic BHA model needed to be developed where the input parameters to the drillstring (such as RPM, Weight on Bit, and mud properties) and the downhole movement data available from the MWD and Rotary steerable tools are combined to recreate down hole conditions. The BHA which was run is then modelled dynamically to establish what borehole misalignment is present. This information is then evaluated to see what localized and summed effect this misalignment has on the inclination derived in the Definitive Dynamic Survey and therefor the impact on TVD and lateral well placement. The results of this study will establish the validity of mis-alignment corrections to be applied to definitive dynamic surveys, it will also allow for further insight into BHA behavior to be made and improved dynamic models to be developed due the new Realtime surveying density that is possible with taking surveys every 20 seconds while drilling. The original theory of random misalignment will be tested with high density downhole data to build a more complete picture of the BHA motion with insights into borehole quality and true well placement becoming possible. This could fundamentally improve TVD errors, with a dramatic reduction in the residual error for SAG corrections having a particular impact on long high angle sections of a given wellbore. Definitive dynamic surveys are novel in that definitive surveys are taken while drilling rather when stationary. The analysis of these high-density surveys provides new insights into borehole quality and geometric well placement. Adding in downhole shock and vibration data with surface information it is possible to see how the BHA is behaving in the borehole and resolve the issue of borehole misalignment and ultimately tool accuracy.
4
Trehan, Rachel, and Bhaskar Roy. "Investigation of Turbine Cascade Blades With Part-Span Sweep With an Open End." In ASME Turbo Expo 2013: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/gt2013-95314.
Анотація:
The present paper focuses on a low-speed computational investigation into the application of backward sweep for application on a typical low-pressure turbine rotor blade. A quasi-two-dimensional linear cascade using T106 profile, was investigated using flow solver Star-CCM+®. Three backward-swept tip modifications (axial sweep, tangential sweep, and a combination of both) have been applied to the baseline profile from 90%–100% span, the rest of the 90% of the blade remained straight and orthogonal to the cascade mainstream flow. The blade stacking axis near the tip was shifted away from the mainstream flow for all three sweep configurations at 15°, 30°, and 45° from the blade axis plane. The impact on pressure losses, tip blade loading, and reduction of tip leakage flow and associated vortices has been analyzed. As the leakage vortex increases in size, causing enhanced blockage to the passage flow, rotor work extraction capability decreases. The application of backward sweep to the blade tip increases the tip cross flow rate, but reduces the turbulent kinetic energy (TKE) across the tip gap. The reduction of TKE of the leakage flow, results in a smaller and less intense tip leakage vortex even though the cross flow rate increases. Minimizing the leakage vortex size and intensity reduces total pressure losses and thereby improves rotor efficiency.
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Gu, Yu S., Joshua D. Roth, Stephen M. Howell, and Maury L. Hull. "How Frequently Do Five Total Arthroplasty Methods Change the Alignment of the Joint Lines and Limb From Normal?" In ASME 2012 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/sbc2012-80477.
Анотація:
One strategy for aligning the limb and positioning components in total knee arthroplasty (TKA) in the coronal plane is mechanical alignment, which has the goal of positioning the center of the hip, knee, and ankle on a straight-line by establishing a femoral and tibial joint line at the knee that is perpendicular to the mechanical axis of the femur and tibia respectively. Another strategy is gap balancing, which has the goal of creating equal gaps between the medial and lateral compartments at 0° of extension and 90° of flexion.
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Meingast, Markus, Robert E. Kielb, and Jeffrey P. Thomas. "Preliminary Flutter Design Method for Supersonic Low Pressure Turbines." In ASME Turbo Expo 2009: Power for Land, Sea, and Air. ASMEDC, 2009. http://dx.doi.org/10.1115/gt2009-59177.
Анотація:
The “Tie-Dye” (TD) method is a well-known preliminary flutter design method for subsonic low pressure turbine (LPT) blades. In this paper, a study of 2D mode shape sensitivity using the TD-method for supersonic exit Mach numbers is presented. Using a harmonic balance CFD method, TD maps displaying the critical reduced frequency for a range of pitching axis locations were created. The TD method was run on two geometrically different blades. Subsonically, the characteristic appearance does not change much over airfoil types. An even lesser amount of morphing can be observed between the different profiles in the supersonic range, than for the subsonic cases. Pure bending modes show a high sensitiviy to the actual bending direction. Therefore the single critical reduced frequency value criteria does not hold up for all cases. The method is applicable for supersonic exit flows, and is even more predictable and universal than for the subsonic cases.
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Hargett, Zachary, Manuel Gutierrez, and Melinda Harman. "Verification of Manual Digitization Methods During Experimental Simulation of Knee Motion." In ASME 2019 Verification and Validation Symposium. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/vvs2019-5158.
Анотація:
Abstract Cadaveric testing is a common approach for verifying mathematical models used in computational modeling work. In the case of a knee joint model for calculating ligament tension during total knee replacement (TKR) motion, model inputs include rigid body motions defined using the Grood-Suntay coordinate system as a spatial linkage between the tibial component orientation relative to the femoral component. Using this approach requires the definition of coordinate systems for each rigid TKR component (i.e. tibial and femoral) based on fiducial points, manual digitization of a point cloud within the experimental setup, and registration of the orientation relative to the relevant bone marker array. The purpose of this study was to compare the variability between two different manual point digitization methods (a hand-held stylus and pivot tool each calibrated in the optical tracking system), using a TKR femoral component in a simulated cadaver limb experimental setup as an example. This was accomplished by verifying the mathematical algorithm used to calculate the coordinate system from the digitized points, quantifying the variability of the manual digitization methods, and discussing how any error could affect the computational model. For the hand-held stylus method, the standard deviation of the origin and, x-, y-, and z-axis calculations were 0.50mm, 1.31 degrees, 0.51 degrees, and 0.62 degrees, respectively. It is important to note that there is an additional error created using the hand-held stylus from required manual digitization of each rigid marker array. This average additional error was 0.54mm for the origin and 1.70, 1.66, and 0.98 degrees for the x-, y-, and z-axes, respectively. For the pivot tool method, the standard deviation was 0.35mm, 0.37 degrees, 1.27 degrees, and 1.24 degrees for the origin, x-, y-, and z-axes, respectively. It is essential to minimize experimental error, as small errors in alignment can substantially alter model outputs. In this study of cadaver simulation of limb motion, the pivot tool is the better option for minimizing error. Careful definition of fiducial points and repeatable manual digitization of the point cloud is critical for meaningful computational models of TKR motion based on cadaver experimental work.
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Swanson, William H., Joel Pokorny, and Vivianne C. Smith. "Phase-dependent sensitivity to heterochromatic flicker: subject differences in color-normal males." In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1986. http://dx.doi.org/10.1364/oam.1986.my6.
Анотація:
We measured sensitivity to sinusoidal temporal modulation as a function of the relative phase of two equally luminant chromatic sources. We previously reported data for three observers at a range of temporal frequencies (OSA 1985); now we report data for a range of observers at a single temporal frequency. The stimuli were presented in a two-channel Maxwellian view system employing red (625-nm) and green (564-nm) light-emitting diodes (LEDs). The two sources were matched by heterochromatic flicker photometry, and their mixture was metameric to ~600 nm. The radiance of the LEDs was controlled by computer-driven electronic circuitry that provided a linear response up to 900 td/LED. A 350 td, 2° test field was superimposed on 8°, 600-nm adapting fields of 100 and 1000 td. We measured modulation sensitivity to 6-Hz flicker for eighteen phases from 0° to 340° and computed an axis of symmetry. Color-normal males had phase axes in the range of 123–173° and 112–156° for adapting fields of 100 and 1000 td (that is, stimulus condition red-leads-green gives minimum sensitivity). In comparison, color-defective males had phase axes of 176–184°. We discuss the data in terms of cone density ratios.
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Mago, V. K., Putcha Venkateswarlu, Ali Miahnahri, P. Chandra Sekhar, and M. C. George. "Parametric study of coherent beam coupling through pulsations and oscillations in self-pumped phase conjugation and transmission." In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1990. http://dx.doi.org/10.1364/oam.1990.mhh2.
Анотація:
Two horizontally polarized coherent beams, A1 and A2, from a He:Ne laser cross in an electrically poled BaTiO3 crystal. The crystal is adjusted so that at least one of the two beams pulsates/oscillates in self-pumping. Energy transfer between the two beams is analyzed with the help of four simultaneously recorded signals, for both individual pumping and simultaneous pumping, under different conditions. A beam (e.g., A1) can be diffracted in the directions of (1) the transmit ted beam (A2T) of the second beam, (2) the phase conjugate (A*2) of the second beam, and (3) the phase conjugate (A*1) of its own beam. Also, the fanning of this beam (A1) may help the other (A2) in its self-pumping. The relative importance of these factors depends the angles of incidence, the point of entry with respect to the crystal edge, and the orientation of the optic axis of the crystal. A study of the energy transfer from these parametric changes and the influence of the pulsations/oscillations on this transfer will be presented.
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Yeh, Tsaiyao, Vivianne C. Smith, and Joel Pokorny. "Data and theory of colorimetric purity discrimination." In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1990. http://dx.doi.org/10.1364/oam.1990.thdd4.
Анотація:
We developed a model using the critical axes from Boynton and Kambe to describe the discrepancy in purity-discrimination data measured from white, ΔP(white), and from the spectrum, ΔP(spectrum). In this study, we used a computer-controlled four-channel Maxwellian view system to investigate the model predictions. For five normal observers, we measured chromatic discrimination steps along the tritan and R/G axis, purity-discrimination functions from white (0.3536,0.3545), and purity-discrimination functions from the spectrum. A double-random staircase, temporal forced-choice paradigm was used. The luminance levels varied from 2.86 to 286 td. In confirmation of the model, the ΔP(white) thresholds were similar to classical data, and the ΔP(spectrum) thresholds at a fixed luminance level depended on the individual observer's tritan discrimination threshold. The data also showed that test luminance level had a major effect on ΔP(spectrum) but only a minor effect on ΔP (white). Furthermore, we observed that a common TVI template cannot describe discrimination changes with both chromaticity and mean luminance. We refined the chromatic discrimination model to account for the main trends of the colorimetric purity data.