Academic literature on the topic 'Surface measurable features'
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Journal articles on the topic "Surface measurable features"
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Podgorny, Igor, Dan Lubin, and Donald K. Perovich. "Monte Carlo Study of UAV-Measurable Albedo over Arctic Sea Ice." Journal of Atmospheric and Oceanic Technology 35, no. 1 (January 2018): 57–66. http://dx.doi.org/10.1175/jtech-d-17-0066.1.
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AbstractIn anticipation that unmanned aerial vehicles (UAVs) will have a useful role in atmospheric energy budget studies over sea ice, a Monte Carlo model is used to investigate three-dimensional radiative transfer over a highly inhomogeneous surface albedo involving open water, sea ice, and melt ponds. The model simulates the spatial variability in 550-nm downwelling irradiance and albedo that a UAV would measure above this surface and underneath an optically thick, horizontally homogeneous cloud. At flight altitudes higher than 100 m above the surface, an airborne radiometer will sample irradiances that are greatly smoothed horizontally as a result of photon multiple reflection. If one is interested in sampling the local energy budget contrasts between specific surface types, then the UAV must fly at a low altitude, typically within 20 m of the surface. Spatial upwelling irradiance variability in larger open water features, on the order of 1000 m wide, will remain apparent as high as 500 m above the surface. To fully investigate the impact of surface feature variability on the energy budget of the lower troposphere ice–ocean system, a UAV needs to fly at a variety of altitudes to determine how individual features contribute to the area-average albedo.
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Matt, S., A. Fujimura, A. Soloviev, S. H. Rhee, and R. Romeiser. "Fine-scale features on the sea surface in SAR satellite imagery – Part 2: Numerical modeling." Ocean Science 10, no. 3 (June 2, 2014): 427–38. http://dx.doi.org/10.5194/os-10-427-2014.
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Abstract. With the advent of the new generation of synthetic aperture radar (SAR) satellites, it has become possible to resolve fine-scale features on the sea surface on the scale of meters. The proper identification of sea surface signatures in SAR imagery can be challenging, since some features may be due to atmospheric distortions (gravity waves, squall lines) or anthropogenic influences (slicks), and may not be related to dynamic processes in the upper ocean. In order to improve our understanding of the nature of fine-scale features on the sea surface and their signature in SAR, we have conducted high-resolution numerical simulations combining a three-dimensional non-hydrostatic computational fluid dynamics model with a radar imaging model. The surface velocity field from the hydrodynamic model is used as input to the radar imaging model. The combined approach reproduces the sea surface signatures in SAR of ship wakes, low-density plumes, and internal waves in a stratified environment. The numerical results are consistent with observations reported in a companion paper on in situ measurements during SAR satellite overpasses. Ocean surface and internal waves are also known to produce a measurable signal in the ocean magnetic field. This paper explores the use of computational fluid dynamics to investigate the magnetic signatures of oceanic processes. This potentially provides a link between SAR signatures of transient ocean dynamics and magnetic field fluctuations in the ocean. We suggest that combining SAR imagery with data from ocean magnetometers may be useful as an additional maritime sensing method. The new approach presented in this work can be extended to other dynamic processes in the upper ocean, including fronts and eddies, and can be a valuable tool for the interpretation of SAR images of the ocean surface.
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Matt, S., A. Fujimura, A. Soloviev, S. H. Rhee, and R. Romeiser. "Fine-scale features on the sea surface in SAR satellite imagery – Part 2: Numerical modeling." Ocean Science Discussions 9, no. 5 (September 17, 2012): 2915–50. http://dx.doi.org/10.5194/osd-9-2915-2012.
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Abstract. With the advent of the new generation of SAR satellites, it has become possible to resolve fine-scale features on the sea surface on the scale of meters. The proper identification of sea surface signatures in SAR imagery can be challenging, since some features may be due to atmospheric distortions (gravity waves, squall lines) or anthropogenic influences (slicks), and may not be related to dynamic processes in the upper ocean. In order to improve our understanding of the nature of fine-scale features on the sea surface and their signature in SAR, we have conducted high-resolution numerical simulations combining a three-dimensional non-hydrostatic computational fluid dynamics model with a radar imaging model. The surface velocity field from the hydrodynamic model is used as input to the radar imaging model. The combined approach reproduces the sea surface signatures in SAR of ship wakes, low density plumes, and internal waves in a stratified environment. The numerical results are consistent with observations reported in a companion paper of in-situ measurements during SAR satellite overpasses. Ocean surface and internal waves are also known to produce a measurable signal in the ocean magnetic field. This paper explores the use of computational fluid dynamics to investigate the magnetic signatures of oceanic processes. This potentially provides a link between SAR signatures of transient ocean dynamics and magnetic field fluctuations in the ocean. We suggest that combining SAR imagery with data from ocean magnetometers may be useful as an additional maritime sensing method. The new approach presented in this work can be extended to other dynamic processes in the upper ocean, including fronts and eddies, and can be a valuable tool for the interpretation of SAR images of the ocean surface.
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Domino, Małgorzata, Marta Borowska, Anna Trojakowska, Natalia Kozłowska, Łukasz Zdrojkowski, Tomasz Jasiński, Graham Smyth, and Małgorzata Maśko. "The Effect of Rider:Horse Bodyweight Ratio on the Superficial Body Temperature of Horse’s Thoracolumbar Region Evaluated by Advanced Thermal Image Processing." Animals 12, no. 2 (January 13, 2022): 195. http://dx.doi.org/10.3390/ani12020195.
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Appropriate matching of rider–horse sizes is becoming an increasingly important issue of riding horses’ care, as the human population becomes heavier. Recently, infrared thermography (IRT) was considered to be effective in differing the effect of 10.6% and 21.3% of the rider:horse bodyweight ratio, but not 10.1% and 15.3%. As IRT images contain many pixels reflecting the complexity of the body’s surface, the pixel relations were assessed by image texture analysis using histogram statistics (HS), gray-level run-length matrix (GLRLM), and gray level co-occurrence matrix (GLCM) approaches. The study aimed to determine differences in texture features of thermal images under the impact of 10–12%, >12 ≤15%, >15 <18% rider:horse bodyweight ratios, respectively. Twelve horses were ridden by each of six riders assigned to light (L), moderate (M), and heavy (H) groups. Thermal images were taken pre- and post-standard exercise and underwent conventional and texture analysis. Texture analysis required image decomposition into red, green, and blue components. Among 372 returned features, 95 HS features, 48 GLRLM features, and 96 GLCH features differed dependent on exercise; whereas 29 HS features, 16 GLRLM features, and 30 GLCH features differed dependent on bodyweight ratio. Contrary to conventional thermal features, the texture heterogeneity measures, InvDefMom, SumEntrp, Entropy, DifVarnc, and DifEntrp, expressed consistent measurable differences when the red component was considered.
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Bechtel, S. E., M. G. Forest, N. T. Youssef, and H. Zhou. "The Effect of Dynamic Surface Tension on the Oscillation of Slender Elliptical Newtonian Jets." Journal of Applied Mechanics 65, no. 3 (September 1, 1998): 694–704. http://dx.doi.org/10.1115/1.2789113.
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We investigate free-surface oscillating jets with elliptical cross section, focusing on behavior associated with decaying surface tension. Previous one-dimensional equations for an oscillating jet are extended to allow variable surface tension on short space and time scales relevant for surfactant mixtures. We presume the decay of surface tension as a function of surface age, and derive the resulting jet behavior. Three plausible forms of decay are studied: an exponential decay, a diffusion model derived in Brazee et al. (1994), and an algebraic form due to Hua and Rosen (1991). Our simulations suggest both experimental regimes, and measurable jet features in these regimes, which may be exploited in an inverse formulation to deduce the unknown rapid surface tension decay of a given surfactant mixture. In particular, we establish numerical relationships between the amplitude and the wavelength of either a sustained far-field oscillation or oscillation at a fixed downstream location and the entire history of surface tension decay. These numerical relationships are ideal for the inverse formulation, in that the complete surface tension evolution may be deduced solely from far-field or downstream jet measurements, away from the confined part of the jet where the surface tension is rapidly changing.
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Berzaghi, Rodrigo, Muhammad Asad Ahktar, Ashraful Islam, Brede D. Pedersen, Turid Hellevik, and Inigo Martinez-Zubiaurre. "Fibroblast-Mediated Immunoregulation of Macrophage Function Is Maintained after Irradiation." Cancers 11, no. 5 (May 17, 2019): 689. http://dx.doi.org/10.3390/cancers11050689.
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The abilities of cancer-associated fibroblasts (CAFs) to regulate immune responses in the context of radiotherapy remain largely unknown. This study was undertaken to determine whether ionizing radiation alters the CAF-mediated immunoregulatory effects on macrophages. CAFs were isolated from freshly-resected non-small cell lung cancer tumors, while monocyte-derived macrophages were prepared from peripheral blood of healthy donors. Experimental settings included both (CAF-macrophage) co-cultures and incubations of M0 and M1-macrophages in the presence of CAF-conditioned medium (CAF-CM). Functional assays to study macrophage polarization/activation included the expression of cell surface markers, production of nitric oxide, secretion of inflammatory cytokines and migratory capacity. We show that CAFs promote changes in M0-macrophages that harmonize with both M1-and M2-phenotypes. Additionally, CAFs inhibit pro-inflammatory features of M1-macrophages by reducing nitric oxide production, pro-inflammatory cytokines, migration, and M1-surface markers expression. Radiation delivered as single-high dose or in fractioned regimens did not modify the immunoregulatory features exerted by CAFs over macrophages in vitro. Protein expression analyses of CAF supernatants showed that irradiated and non-irradiated CAFs produce approximately the same protein levels of immunoregulators. Thus, CAF-derived soluble factors mediate measurable changes on uncommitted macrophages and down-regulate pro-inflammatory features of M1-polarized macrophages. Notably, ionizing radiation does not curtail the CAF-mediated immunosuppressive effects.
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Rutherford, A. C., D. J. Inman, G. Park, and F. M. Hemez. "Use of Response Surface Metamodels for Identification of Stiffness and Damping Coefficients in a Simple Dynamic System." Shock and Vibration 12, no. 5 (2005): 317–31. http://dx.doi.org/10.1155/2005/484283.
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Metamodels have been used with success in many areas of engineering for decades but only recently in the field of structural dynamics. A metamodel is a fast running surrogate that is typically used to aid an analyst or test engineer in the fast and efficient exploration of the design space. Response surface metamodels are used in this work to perform parameter identification of a simple five degree of freedom system, motivated by their low training requirements and ease of use. In structural dynamics applications, response surface metamodels have been utilized in a forward sense, for activities such as sensitivity analysis or uncertainty quantification. In this study a polynomial response surface model is developed, relating system parameters to measurable output features. Once this relationship is established, the response surface is used in an inverse sense to identify system parameters from measured output features.A design of experiments is utilized to choose points, representing a fraction of the full design space of interest, for fitting the response surface metamodel. Two parameters commonly used to characterize damage in a structural system, stiffness and damping, are identified. First changes are identified and located with success in a linear 5DOF system. Then parameter identification is attempted with a nonlinear 5DOF system and limited success is achieved. This work will demonstrate that use of response surface metamodels in an inverse sense shows promise for use in system parameter identification for both linear and weakly nonlinear systems and that the method has potential for use in damage identification applications.
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Jerison, Harry J. "Digitized Fossil Brains: Neocorticalization." Biolinguistics 6, no. 3-4 (November 28, 2012): 383–92. http://dx.doi.org/10.5964/bioling.8929.
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This report is based on 3D digital scans of endocasts of 110 species of fossil mammals and 35 species of living mammals. It presents direct evidence of the last 60 million years of brain evolution. Endocasts are casts of the cranial cavity. They are brainlike in size and shape, and their surface features can be named as if they were brain structures. Although endocast data are restricted to outer surfaces of brains, a few inferences about inner structure are possible. Neocortex in the forebrain, for example, is identifiable and measurable as cerebral forebrain on the endocast dorsal to the rhinal fissure. An important result in this report is that surface area of neocortex as identified on endocasts appears to have reached a maximum of about 80% of the total endocast surface area in anthropoid primates including humans. This may be a fundamental limitation in brain size. The average neocorticalization percentage for mammals as a whole rose from about 20% to about 50% of the surface area during the 60 million years covered by this analysis. Neocorticalization is associated with the evolution of higher mental processes, including the evolution of language as a hominin specialization. The limitation of the increase in relative amount of neocortex is similar in all anthropoids. Neocortex is greater in absolute area in living humans because the total size of the hominin brain is so much larger than in other primates.
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Hurst, Martin D., Simon M. Mudd, Mikael Attal, and George Hilley. "Hillslopes Record the Growth and Decay of Landscapes." Science 341, no. 6148 (August 22, 2013): 868–71. http://dx.doi.org/10.1126/science.1241791.
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Earth's surface archives the combined history of tectonics and erosion, which tend to roughen landscapes, and sediment transport and deposition, which smooth them. We analyzed hillslope morphology in the tectonically active Dragon’s Back Pressure Ridge in California, United States, to assess whether tectonic uplift history can be reconstructed using measurable attributes of hillslope features within landscapes. Hilltop curvature and hillslope relief mirror measured rates of vertical displacement caused by tectonic forcing, and their relationships are consistent with those expected when idealizing hillslope transport as a nonlinear diffusion process. Hilltop curvature lags behind relief in its response to changing erosion rates, allowing growing landscapes to be distinguished from decaying landscapes. Numerical modeling demonstrates that hillslope morphology may be used to infer changes in tectonic rates.
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Huang, Zhiwen, Jianmin Zhu, Jingtao Lei, Xiaoru Li, and Fengqing Tian. "Tool Wear Monitoring with Vibration Signals Based on Short-Time Fourier Transform and Deep Convolutional Neural Network in Milling." Mathematical Problems in Engineering 2021 (June 30, 2021): 1–14. http://dx.doi.org/10.1155/2021/9976939.
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Tool wear monitoring is essential in precision manufacturing to improve surface quality, increase machining efficiency, and reduce manufacturing cost. Although tool wear can be reflected by measurable signals in automatic machining operations, with the increase of collected data, features are manually extracted and optimized, which lowers monitoring efficiency and increases prediction error. For addressing the aforementioned problems, this paper proposes a tool wear monitoring method using vibration signal based on short-time Fourier transform (STFT) and deep convolutional neural network (DCNN) in milling operations. First, the image representation of acquired vibration signals is obtained based on STFT, and then the DCNN model is designed to establish the relationship between obtained time-frequency maps and tool wear, which performs adaptive feature extraction and automatic tool wear prediction. Moreover, this method is demonstrated by employing three tool wear experimental datasets collected from three-flute ball nose tungsten carbide cutter of a high-speed CNC machine under dry milling. Finally, the experimental results prove that the proposed method is more accurate and relatively reliable than other compared methods.
Dissertations / Theses on the topic "Surface measurable features"
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Laffan, Shawn William, and Shawn Laffan@unsw edu au. "Inferring the Spatial Distribution of Regolith Properties Using Surface Measurable Features." The Australian National University. School of Resources, Environment and Society, 2001. http://thesis.anu.edu.au./public/adt-ANU20040714.155019.
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The aim of this research is to determine to what extent properties of the regolith may be inferred using only features easily measured from the surface. To address this research question, a set of regolith properties from Weipa, Queensland, Australia, are analysed. The set contains five variables, oxides of Aluminium, Iron, Silica and Titanium, as well as Depth to Ironstone. This last represents the depth of the layer from which the oxides are sampled.¶ The research question is addressed in two ways. First, locations where the properties are related to modern surface hydrology are assessed using spatially explicit analyses. This is done by comparing the results of spatial association statistics using geometric and watershed-based spatial samples. Second, correlations are sought for between the regolith properties and geomorphometric indices of land surface morphology and Landsat Thematic Mapper spectral response. This is done using spatially implicit Artificial Neural Networks (ANN) and spatially explicit Geographically Weighted Regression (GWR). The results indicate that the degree to which regolith properties are related to surface measurable features is limited and spatially variable.¶ Most locations in the Weipa landscape exhibit some degree of modern hydrological control of the oxide variables at lateral distances of 120 m. This control rarely extends beyond 300 m laterally, although such locations occupy distinct positions in the landscape. Conversely, there is an extensive part of the landscape where Depth to Ironstone is under hydrological control. This occupies most of the lower elevations in the study area. Depth to Ironstone represents the depth to the redox front where iron is precipitated, but may in some parts of the landscape control the distribution of the watertable by being impermeable.¶ For the correlation analyses, the highest correlations are found with those oxides most mobile in solution. The spatially local GWR results also consistently outperform the spatially global ANN results, commonly having accuracies 40% higher at the error tolerance used. Much of this can be attributed to the localized effects of landscape evolution. Comparison of the GWR results against the local sample mean indicate that there is a relationship between regolith properties and surface measurable features at 10-15% of sample locations for the oxide variables, and 22% for Depth to Ironstone.¶ The implications of these results are significant for anyone intending to generate spatial datasets of regolith properties. If there is a low spatial density of sample data, then the effects of landscape evolution can reduce the utility of any analysis results. Instead, spatially dense, direct measurements of subsurface regolith properties are needed. While these may not be a direct measurement of the property of interest, they may provide useful additional information by which these may be inferred.
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Laffan, Shawn. "Inferring the Spatial Distribution of Regolith Properties Using Surface Measurable Features." Phd thesis, 2001. http://hdl.handle.net/1885/47656.
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The aim of this research is to determine to what extent properties of the regolith may be inferred using only features easily measured from the surface. To address this research question, a set of regolith properties from Weipa, Queensland, Australia, are analysed. The set contains five variables, oxides of Aluminium, Iron, Silica and Titanium, as well as Depth to Ironstone. This last represents the depth of the layer from which the oxides are sampled.¶ The research question is addressed in two ways. First, locations where the properties are related to modern surface hydrology are assessed using spatially explicit analyses. This is done by comparing the results of spatial association statistics using geometric and watershed-based spatial samples. Second, correlations are sought for between the regolith properties and geomorphometric indices of land surface morphology and Landsat Thematic Mapper spectral response. This is done using spatially implicit Artificial Neural Networks (ANN) and spatially explicit Geographically Weighted Regression (GWR). The results indicate that the degree to which regolith properties are related to surface measurable features is limited and spatially variable.¶ ... ¶ The implications of these results are significant for anyone intending to generate spatial datasets of regolith properties. If there is a low spatial density of sample data, then the effects of landscape evolution can reduce the utility of any analysis results. Instead, spatially dense, direct measurements of subsurface regolith properties are needed. While these may not be a direct measurement of the property of interest, they may provide useful additional information by which these may be inferred.
Book chapters on the topic "Surface measurable features"
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Criss, Robert E., and Anne M. Hofmeister. "How spin down and radioactive decay drive rocky planet evolution." In In the Footsteps of Warren B. Hamilton: New Ideas in Earth Science. Geological Society of America, 2022. http://dx.doi.org/10.1130/2021.2553(19).
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ABSTRACT Most differences in the gross surface morphologies, tectonic styles, overall geologic histories, and atmospheres of the rocky bodies in the solar system can be explained by contributions and dissipation of gravitational and radiogenic energy over geologic time. These two energy sources are large and measurable and can be extrapolated back in time. Accretion was likely cold, and directly converted gravitational potential energy into axial spin, a prominent feature of planets that is otherwise unexplained. Impact heating was mostly limited to planetary surfaces in the final stages of accretion. Frictional dissipation of spin contributed sufficient energy to ignite the primordial Sun and heated Earth and Venus by nearly as much as has the radioactive decay of K, U, and Th over geologic time. Energy inputs have been continuously offset by loss of heat to the surroundings. The magnitudes of most important energy contributions depend on the planet radius R and also on the distance r to the Sun. Quantitative, albeit approximate, relationships show that the net specific energy (kJ/kg) contributed to the rocky bodies over geologic time goes as: Earth ~ Venus >> Mars ~ Mercury ~ Moon >> asteroids. Net energy inputs increased the average internal temperatures of Earth and Venus by ~3000 K but heated asteroids by only a few hundred kelvins.
Conference papers on the topic "Surface measurable features"
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Amari, Shoma, Midori Tanaka, and Takahiko Horiuchi. "MODELLING OF PERCEPTUAL GLOSS BY PHYSICAL MEASUREMENT OF FLAT SURFACE." In CIE 2021 Conference. International Commission on Illumination, CIE, 2021. http://dx.doi.org/10.25039/x48.2021.op10.
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While ‘physical gloss’ exists as a physically measurable index, people perceive a ‘perceptual gloss’ as gloss on object surfaces. However, the physical gloss does not always match the perceptual gloss. Thus, we analysed the relationship between physical features and perceptual gloss by measuring the physical properties of object surfaces, including physical gloss. For the experiment, we prepared 127 samples of flat objects that consisted of three materials: paper, resin, and metal plating. Perceptual gloss was visually evaluated using a magnitude estimation method. Plural measurements were conducted to obtain physical features such as gloss unit, haze, distinctness of image (DOI), luminance image features, and transmittance of the samples. Then, we constructed a prediction model of perceptual gloss using these physical features and perceptual gloss through multiple regression analysis. As a result, the prediction accuracy was improved by combining multiple physical quantities with simple regression, using only a gloss unit.
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Segala, David B., David Chelidze, Albert Adams, Jeffrey M. Schiffman, and Leif Hasselquist. "Tracking Physiological Fatigue in Prolonged Load Carriage Walking Using Phase Space Warping and Smooth Orthogonal Decomposition." In ASME 2008 International Mechanical Engineering Congress and Exposition. ASMEDC, 2008. http://dx.doi.org/10.1115/imece2008-67329.
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The ability to track and predict the onset of physiologic fatigue using easily measurable variables is of great importance to both civilian and military activities. In this paper, biomechanical gait variables are used to reconstruct fatigue evolution in subjects walking with a 40 kg load on a level treadmill for two hours. Fatigue is reconstructed in two steps: (1) phase space warping based feature vectors are estimated from gait variable time series; and (2) smooth orthogonal decomposition is used to extract fatigue related trends from these features. These results are verified using independently obtained measures of fatigue from breath-by-breath oxygen consumption (V˙O2) and surface electromyography (EMG) from a set of leg muscles. V˙O2 based measures for some subjects show no discernable trends. However, for a subject showing monotonically increasing oxygen consumption, the reconstructed dominant fatigue variable closely track V˙O2 measure reflecting global systemic fatigue. For the muscles showing variation in EMG-based fatigue measures, the reconstructed fatigue variables also closely track these local muscle trends. The results show that kinematic angles, which are easier quantities to measure in the field, can be used to track and predict the onset of fatigue.
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Annicchiarico, Claudio, Mirko Rinchi, Stefano Pellari, and Renzo Capitani. "Design of a Semi Active Differential to Improve the Vehicle Dynamics." In ASME 2014 12th Biennial Conference on Engineering Systems Design and Analysis. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/esda2014-20157.
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Suppressing or limiting the differential action of the differential mechanism is the mostly adopted technique to avoid the skidding of a driving wheel of a vehicle riding on a poorly adherent surface. The devices carrying out this function unbalance the traction force distribution in the differential, generating a yaw torque acting on the vehicle as a secondary effect. If the unbalancing action is electronically controlled, this yaw torque can be used to affect the attitude of car as a torque vectoring technique. In this paper, a purpose built differential is presented and its technical features are highlighted, including the electrohydraulic actuation. Moreover, its torque vectoring capabilities are discussed, basing on the numerical simulation campaign performed deploying this device in a 7 DOFs model of a race car with low ground effect. The results of these simulations are compared with the behavior of the same vehicle equipped with a common passive locking differential, to show that the proposed one and its control logic (which relies on only measurable inputs) are able of improving the handling of the vehicle, in terms of both vehicle stability and linearity with the driver’s inputs. Therefore, this system could be considered as a completion of the common ESC (“Electronic Stability Control) systems to control the vehicle attitude when using the brake system is an inefficient solution.
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Nagy, Jason, and Xiao Huang. "Assessing the Feasibility of Micro-Plasma Technology for Additive Manufacturing." In ASME Turbo Expo 2018: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/gt2018-75119.
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In this research, a micro-plasma system was investigated for its capability in additive manufacturing (AM). Micro-plasma AM system has the advantage of lower cost and higher deposition rate over laser based AM systems, and generates leaner and cleaner weld deposit than other arc based AM systems. However, the micro-plasma system is complex and involves a large number of process variables. In this study, the feasibility of using a micro-plasma system for additive manufacturing was assessed based on surface features, mechanical properties and microstructure. In addition, two arc and wire feed modes were examined to understand the effects of these two variables. Each was used to produce IN 718 superalloy samples for macro- and microstructure evaluation, hardness, wear, and tensile tests along both long and transverse directions. Preliminary results showed that crack free samples, measured up to 100 mm × 40 mm, can be generated without measurable distortion. Some surface discoloration was observed, ranging from light straw to a purple tint. After heat treatment, the hardness of the samples varies from 403 to 440 HV, with the transverse surface showing slightly lower hardness values. Pin-on-disk wear test yielded consistent wear volume for three sets of the samples produced using different process parameters; however, samples produced with no modifications to the current and wire feed mode showed marginally higher wear rate. Microstructural analysis with SEM and EDS revealed presence of small pinholes, measured from submicron up to 22 μm in diameter, and no indication of any cracks or boundary layers between passes. SEM analysis revealed the presence of high contrast Nb/Mo rich carbides along with γ″-Ni3Nb in the γ matrix. Finally, tensile test was carried out to understand the anisotropic behavior; the results showed that transverse direction had lower tensile strength and ductility. Samples produced with pulsed current and wire feed mode had lower yield/tensile strength but higher ductility than that without current and wire feed mode modification.
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Feng, Dong, Zhangxin Chen, Zenghua Zhang, Peihuan Li, Yu Chen, Keliu Wu, and Jing Li. "Effect of Surface Wettability on the Miscible Behaviors Of Co2-Hydrocarbon in Shale Nanopores." In SPE EuropEC - Europe Energy Conference featured at the 83rd EAGE Annual Conference & Exhibition. SPE, 2022. http://dx.doi.org/10.2118/209708-ms.
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Abstract The minimum miscible pressure (Pm) of CO2-hydrocarbon mixtures in nanopores is a key parameter for CO2-enhanced shale oil recovery. Although the miscible behaviors of CO2-hydrocarbon mixtures in nanopores have been widely investigated through the simulations and calculations, the heterogeneity of shale components with different affinity to hydrocarbons results in the deviation of traditional predictions and motivates us to investigate how the surface properties influence the CO2-hydrocarbon miscible behaviors in nanopores. In this work, we established a model and framework to determine the wettability-dependent physical phenomena and its impact on the Pm of CO2-hydrocarbon in shale nanopores. First, a generalized scaling rule is established to clarify the potential correlation between critical properties shift and wettability based on the analysis of microscopic interactions (fluid-surface interactions and fluid-fluid interactions). Second, a wettability-dependent SKR EOS is structured and a generalized and practical framework for confined phase behavior with different surface wettability is constructed. Subsequently, the Pm of CO2-hydrocarbon mixtures in confined space with various wettability is evaluated with our model. The calculated results demonstrate that the nanoconfined effects on Pm not only relate to the pore dimension but also depend on the contact angle. In an intermediate-wet nanopore, the minimum miscible pressure approaches the bulk value. In an oil-wet nanopore with a width smaller than 100nm, the minimum miscible pressure is suppressed by the confined effects, and the reduction is further strengthened with a reduction in pore dimension and increase of wall-hydrocarbon affinity. Our work uses a macroscopically measurable parameter (contact angle) to characterize the shift of critical properties derived from the microscopic interactions, and further construct a generalized and practical framework for phase behavior and minimum miscible pressure determination in nanopores with different surface properties. The method and framework can make a significant contribution in the area of upscaling a molecular or nanoscale understanding to a reservoir scale simulation in shale gas/oil research.
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Beck, B. Terry, Aaron A. Robertson, Robert J. Peterman, Kyle A. Riding, and John Wu. "Accuracy of High Resolution 3D Optical Scanning of Crosstie Geometry for Assessment of Cross-Sectional Parameters and Long-Term Abrasion and Wear." In 2017 Joint Rail Conference. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/jrc2017-2296.
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Current research is attempting to develop a comprehensive understanding of the material and manufacturing characteristics that have caused splitting failures in prestressed concrete railroad ties, in contrast with those characteristics that have resulted in ties that have performed well after many years in track. As part of this effort, a three-dimensional (3D) Optical Scanning System is being used to accurately scan and quantify the surface geometry and volume (abrasion and wear) of a large sample of previously manufactured ties. A commercially-available 3D Laser-Based Optical Scanning System, having a maximum spatial resolution of approximately 0.1mm, is being used to perform the surface scanning operation. The scanning procedure ideally produces an accurate 3D CAD model of the tie geometry, which can then be analyzed to determine the desired geometrical features at any given cross-section. It can likewise yield a measure of the tie volume, the variation of which gives some direct indication of the extent of abrasion and wear. The feasibility of the scanning system has previously been demonstrated by extracting the detailed longitudinal variation of geometrical cross-section crosstie parameters of a typical CXT tie, including cross-sectional area, centroid, moment of inertia, and the eccentricity of the prestressing wires. These parameters are also known to be of importance to the accurate determination of transfer length from measured surface strain. The CXT tie geometry provides an excellent test case, and a challenge to the optical scanning system, since it has a complex scalloping along its length. While the basic feasibility of the system operation has been demonstrated, the repeatability of the geometrical information obtained from the overall scanning and subsequent post-processing of surface geometrical data has yet to be assessed. The main objective of this paper is to first demonstrate the volumetric measurement resolution experimentally by conducting repeated scans of the same tie by the same operator. The experimental scatter in scan results is presented for both cross-section parameter detail and tie volume assessment. The statistical variation in the measured tie volume ideally provides a reasonable measure of the expected volume resolution. In addition to assessing the statistics of these repeated scans, a CXT tie was subjected to induced abrasions of known (measurable) volume for direct comparison with the volume measurements obtained using the optical scanning procedure. This work represents an important next step toward identifying the accuracy of the assessment of abrasion and wear for the large number of ties currently being scanned after having been in long-term service.
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Yapa, Sayuri D., Christopher J. Elkins, and John K. Eaton. "Endwall Vortex Effects on Turbulent Dispersion of Film Coolant in a Turbine Vane Cascade." In ASME Turbo Expo 2014: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/gt2014-25484.
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Turbine vane cascades produce strong secondary flows due to flow turning. The dominant flow feature is the passage vortex, located in the corner between the endwall and the suction surface of the airfoil. Full-field, 3D velocity and concentration measurements were made using magnetic resonance imaging to study turbulent mixing in a realistic film-cooled nozzle vane cascade. The passage vortex has large effects on the flow features in the vane wake and consequently, on coolant mixing. Cross-flow vorticity on the vane’s suction side rolls up and forms the suction-side leg of the horseshoe vortex, which then interacts with the cross-flow boundary layer and rolls up into the passage vortex. The passage vortex does not measurably increase the turbulent diffusivity, although it does strongly distort streamlines near the endwall.
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Lomario, D., G. P. De Poli, L. Fattore, and J. Marczyk. "A Complexity-Based Approach to Robust Design and Structural Assessment of Aero Engine Components." In ASME Turbo Expo 2007: Power for Land, Sea, and Air. ASMEDC, 2007. http://dx.doi.org/10.1115/gt2007-27205.
Full textAbstract:
This paper presents a complexity-based methodology for the design of aero engine components. Upon a rigorous definition of complex system, a metric for the complexity is introduced as a function of system’s topology and entropy. As a consequence, complexity becomes a measurable and manageable property of systems. Furthermore, a novel definition of robustness is provided, based on the shape of the probability density functions (PDF) of the performances. Complexity and robustness are related together by a simple, qualitative law. Based on these premises, two algorithms are introduced, namely the Stochastic Design Improvement (SDI) and the Complex Systems Analyzer (CSA). The former searches the design space seeking for solutions which meet the design requirements. The latter extracts the fundamental features of the design, previously perturbed by means of Monte Carlo Simulation (MCS). The SDI is proposed as a competitor of the practice of optimization. Though both can be used separately, the combination of SDI and CSA provides a powerful novel method for design. The capabilities of the algorithms are illustrated on three test-cases, namely an LPT Casing, a Turbo-prop bearing retainer and an LPT disk. It is important to point out that response surfaces or other surrogates have never been used.
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YASUNO, TAKATO, JUNICHIRO FUJII, MICHIHIRO NAKAJIMA, and KAZUHIRO NODA. "BRIDGE SLAB ANOMALY DETECTOR USING U-NET GENERATOR WITH PATCH DISCRIMINATOR FOR ROBUST PROGNOSIS." In Structural Health Monitoring 2021. Destech Publications, Inc., 2022. http://dx.doi.org/10.12783/shm2021/36276.
Full textAbstract:
More than 50 years aging civil infrastructures have deteriorated, then structural diagnosis and periodic prognosis become critical for predictive maintenance. In terms of the bridge inspection every 5 years in Japan, we have collected a lot of human eye inspection. In context of digital structural monitoring, in addition to the past human inspection we make the most of drone flight images. However, human subjective judge includes individual bias, then a measurable objective score should be quantified using a unified anomaly distance from a health condition. Supervised learning, e.g. classification and semantic segmentation method is not always robust for unseen data. If we address the unlearned blind feature without any experience, prediction error might be a higher hurdle to overcome low precision and less recall problem. The generative anomaly detection via unsupervised learning has been growing in various fields, e.g. medical, manufacturing, food, and materials. If the distance and angle to the target damage interest could be controlled among a feasible range, and if the background noise could be removed and relaxed, then concrete surface damage and steel paint peel or corrosion would enable to discriminate them for predictive maintenance. In this paper, we propose a steel anomaly detector method to compute anomalous scores automatically, where we customize several U-shape skip-connected generator network with patch GAN discriminator. Exactly, we have create an encoder-decoder network using the VGG19 based U-Net generator with a patch discriminator. Furthermore, we explore robust unified anomaly score indicator for the target concrete and painted steel parts to analyze deterioration prognosis, so as to monitor the current status far from a health condition. Finally, focusing on the bridge slab, we exploit toward the inspection images with the number of 10,400, where they contains reinforcement concrete slab at 400 bridges under the direct control of national managers. In order to be stable learning and robust structural health monitoring, we demonstrate to visualize several anomalous feature map for precisely and full-covered digital inspection.
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Brosch, Erwin. "Data-Based Parameterization of Thermal Models of a Gearbox." In FISITA World Congress 2021. FISITA, 2021. http://dx.doi.org/10.46720/f2020-adm-126.
Full textAbstract:
Conventional gear units are installed in almost all vehicles manufactured and developed these days in particular Battery Electric Vehicles (BEV). Despite the already very high sophisticated development of gearboxes, the focus on optimizing mass and efficiency is still important in development. Especially for BEV the efficiency becomes very important. A remarkable feature of a high efficient transmission of a BEV is the low mass and resulting reduced thermal masses. An additional significant challenge is posed by generally higher engine speed of BEVs, which leads to an increase of heat influx in the gearboxes. Overall, the thermal stability of the transmission units decreases, thus the importance of the temperature monitoring is increased. Oftentimes a model is needed for this, especially for topics such as thermal design with regard to temperature distribution or cooling effects on the surface. Under certain conditions having such a model on a test bench facilitates the avoidance of setting a temperature measuring point. In the scope of this work, a potential solution is shown to infer the inner temperature of the gearbox by using measurable temperature on the outer surface. The surface temperatures of the gearbox can be measured on a test bench by sticking sensors onto it. Furthermore using thermal imaging cameras or other methods based on infrared enable contact free measurements. In order to be able to deduce the inner temperature prevailing in the gearbox from these easily determined surface temperatures, a well-known and frequently used thermal model is created, which is based on the simple foundation of thermal networks. For this concrete application, a thermal network with a small number of thermal nodes and therefore low complexity is created. One node represents the point to be observed inside the gearbox, the others are either a heat sink or heat source or a point where the temperature is known or measured. Even these relatively simple models reveal a large number of parameters. These need to be determined, because each thermal source or sink as well as each transition needs to be parameterized. Determining these parameters demands detailed knowledge of the particular transmission unit. To avoid this, a method from the field of machine learning is applied. For this purpose, the gearbox to be modelled or an identical gearbox is analyzed on a test bench. Both, external and internal temperatures are recorded. In addition, data such as speed and power, which are usually available anyway, are required. Based on a sufficiently large data set, the optimization criterion for the approach is created. A method, which is based on evolutionary algorithms is verified using the example of a single-stage differential transmission. For this purpose, measurements on a driveline test bench are collected and evaluated. A model and its parameters are determined and subsequently compared with temperature measurements, derived from the inside of the transmission unit.