Academic literature on the topic 'Undulation index'
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Journal articles on the topic "Undulation index"
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Kropáč, O., and P. Múčka. "Longitudinal road unevenness with periodic components: Characterization and effects on people in a traversing vehicle and the loading of the pavement." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 219, no. 6 (June 1, 2005): 773–90. http://dx.doi.org/10.1243/095440705x28394.
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Firstly, the effect of periodic components (undulation) appearing in the otherwise random longitudinal profile of road on standard indicators of random unevenness is studied. The power spectral density characterized by its parameters, i.e. the unevenness index and waviness, three band variances, and international roughness index are considered. Secondly, a series of simulation examples is given of the response of two planar vehicle models (a passenger car and a truck) traversing along the road with periodic components of longitudinal unevenness. The effects on people sitting in the vehicle and on the loading of the vehicle undercarriage and pavement structure are studied. The wavelengths of undulation and the running speeds that appear as most inconvenient are emphasized
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Thannoun, Rayan. "Three Dimensional Terrain Modeling for Tectonic Geomorphology of Chinara Anticline, Northern Iraq." Iraqi Geological Journal 54, no. 1C (March 31, 2021): 53–65. http://dx.doi.org/10.46717/igj.54.1c.5ms-2021-03-25.
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Analysis of the terrain using three-dimensional models offers a deep insight view of ground surface topography and terrain representation. The Chinara anticline is one of the main structures of NW-SE trends for the highly folded zone in northeastern Iraq. The objective of this study is to understand the interrelationship between topography and morphotectonic features using three-dimensional models. This research employed fourth generates principal raster derivative products from the DEM using ArcGIS. To understand the undulating of this anticline with the morphotectonic style, the adaptive equation has been suggested to determine the direction and amount of the main tectonic forces, which can be applied to other undulated anticlines. The values of northeastern and southwestern limbs undulating index UI are 11.7 and 7.8 respectively that indicates the strong tectonic force towards the northeast. Two listric faults have been conducted via the field survey that confirmed by remotely sensed interpretation and DEM products. These listric faults had an intensive impact in comparison with concluded strike-slip faults, and then the Chinara anticline would be less structural undulating in a region of vicinity syncline to Perat undulation. The morphotectonic landscapes reveal that the listric fault has branched into two parts, the first one extending to form the anticline and the other comprises the structural dilemma.
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Omri, Mohamed, Muhammad Jamal, Shafqat Hussain, Lioua Kolsi, and Chemseddine Maatki. "Conjugate Natural Convection of a Hybrid Nanofluid in a Cavity Filled with Porous and Non-Newtonian Layers: The Impact of the Power Law Index." Mathematics 10, no. 12 (June 13, 2022): 2044. http://dx.doi.org/10.3390/math10122044.
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This study deals with the effect of the power law index on the convective heat transfer of hybrid nanofluids in a square cavity divided into three layers. The effect of a solid fluid layer is also given attention. A two-dimensional system of partial differential equations is discretized by using the generalized finite element method (FEM). A FEM having cubic polynomials (P3) is employed to approximate the temperature and velocity components, whereas the pressure is approached using quadratic finite element functions. The discretized set of equations have been solved using Newton’s method. The numerical code which is used in this study has been validated by comparing with experimental findings. Mathematical simulations are performed for different sets of parameters, including the Rayleigh number (between 103 and 106), the power law index (between 0.6 to 1.8), Darcy number (between 10−6 to 10−2), undulation (between 1 and 5) and the thermal conductivity ratio (between 0.1 and 10). The results infer that a remarkable penetration of streamlines is figured out towards the porous hybrid layer as the power law index is increased. The average Nu increases with increasing Ra, and the maximum value is noted at Ra=106. There is no much alteration observed for isotherms at the solid layer by increasing Da. The average Nu decreases by increasing the undulations. The rate of heat transfer is enhanced at the heated boundary and solid fluid interface of the cavity by raising the ratio of thermal conductivity.
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Colip, Charles G., Sean Wo, Daniel S. Hippe, Hiroko Watase, Alfonso R. Urdaneta-Moncada, Chengcheng Zhu, Lei Wu, et al. "Computed tomography angiography findings predictive of post-intervention vasospasm in patients with aneurysmal subarachnoid hemorrhage." British Journal of Radiology 94, no. 1121 (May 1, 2021): 20200893. http://dx.doi.org/10.1259/bjr.20200893.
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Objective: To evaluate the association of CT/CT angiography (CTA) findings and clinical characteristics with subsequent vasospasm in patients with aneurysmal subarachnoid hemorrhage (aSAH). Methods-: Consecutive presentation CTA head exams in patients with aSAH between January 2005 and June 2015 were retrospectively evaluated for intracranial arterial calcification, undulation and non-calcified stenosis. Additional variables including modified Fisher Scale (mFS), Glasgow Coma Scale (GCS) and neurological exam status were reviewed. Associations of CTA findings with the incidence of angiographic vasospasm were assessed with multivariate logistic regression models using the least absolute shrinkage and selection operator machine-learning algorithm. Model performance was summarized using c-index with bootstrap optimism-adjustment. Results Intracranial arterial calcification, seen in 51.7% of 195 total patients, was protective against vasospasm (OR-0.6; 95% CI-0.52–0.67; p = 0.009), while arterial undulation (24%) was associated with subsequent vasospasm (OR-2.6; 95% CI-1.3–5.1; p = 0.007). Non-calcified intracranial arterial stenosis (5%) was associated with subsequent vasospasm, (OR-4.7; 95% CI-1.0–22.8; p = 0.054). Least absolute shrinkage and selection operator selected all three CTA findings as predictors in a multivariate model for vasospasm in addition to clinical factors, which demonstrated superior predictive performance (c-index-0.74; 95% CI-0.69–0.82) compared to a model based on mFS and clinical factors only (c-index-0.66; 95% CI-0.57–0.75; p = 0.010 for the difference). Conclusion: Presentation CTA findings combined with clinical factors may better predict the development of vasospasm in patients with aSAH compared to current prognostic models alone. Advances in knowledge: The combination of initial CT/CTA and clinical findings better predict development of vasospasm after aSAH. This can lead to better markers for use in future clinical trials to develop vasospasm preventative treatments and potentially provide better targets for early aggressive treatment.
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Sun, Yong Jun, and Yi Qu. "Study on the Maintenance Capacity of “Man-Machine System” Based on Fuzzy Comprehensive Evaluation." Applied Mechanics and Materials 203 (October 2012): 479–83. http://dx.doi.org/10.4028/www.scientific.net/amm.203.479.
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This paper, in accordance with the maintenance capacity of “Man-Machine System”, holds the core of the “Man-Machine System” and employs the analysis methods of the complex system, brings forward the model of the three-layer comprehensive evaluation based on fuzzy mathematics, then brings out the methods of the index weight and studies the maintenance capacity’s evaluation algorithm on the foundation of the quantitative analysis. In the last it gives the application of the model and algorithm by using the instances and studies the changing maintenance capacity including the stability and the undulation, which provides one thought for scientifically evaluating the maintenance capacity of “Man-Machine System”.
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Conceição, Ana, António J. Silva, José Boaventura, Daniel A. Marinho, and Hugo Louro. "Wave Characteristics in Breaststroke Technique with and Without Snorkel Use." Journal of Human Kinetics 39, no. 1 (December 1, 2013): 185–94. http://dx.doi.org/10.2478/hukin-2013-0081.
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Abstract The purpose of this paper was to examine the characteristics of waves generated when swimming with and without the use of Aquatrainer® snorkels. Eight male swimmers performed two maximal bouts of 25 m breaststroke, first without the use of a snorkel (normal condition) and then using a snorkel (snorkel condition). The body landmarks, centre of the mass velocity, stroke rate, stroke length, stroke index, and Strouhal number (St) were quantified. Fourier analysis was conducted to determine the frequency, amplitude, and phase characteristics of the vertical undulations. We also determined the undulation period, the first and second harmonic wave percentage, and the contribution of these components to the power of each of the wave signals. The first wave harmonics had a frequency of 0.76 Hz (normal condition) and 0.78 Hz (snorkel condition), and the second wave harmonics had a frequency of 1.52 Hz (normal condition) and 1.56 Hz (snorkel condition). Under the normal conditions, the wave amplitude was higher on the vertex (0.72 m) and cervical (0.32 m) than that produced under snorkel conditions (0.71 m and 0.28 m, respectively). The lowest values were found in the hip (0.03 m in normal conditions, and 0.02 m in snorkel conditions) and in the trunk (0.06 m in normal conditions, and 0.04 m in snorkel conditions). It can be concluded that snorkel use seems to lead to slight changes in the biomechanical pattern in swimming velocity, as well as several stroke mechanical variables.
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Tsai, Ming Chang, and Shyh Chour Huang. "The Analysis of Pulse Pressure by Vascular Strain." Applied Mechanics and Materials 256-259 (December 2012): 2383–86. http://dx.doi.org/10.4028/www.scientific.net/amm.256-259.2383.
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The objective of this paper is to use the Noninvasive Strain Measurement System to monitor the pulse pressure of the blood’s undulation in the artery as an index for the clinical diagnosis of arteriosclerosis. In the study, a strain-measuring device (350Ω) is affixed to the left side of the radial styloid process, on the surface of the skin, and is connected to the Strain FleXense. An artery-pressuring tape is set on the left humerus, and the measurement of the wavelength and frequency of the heartbeat is taken to compare with the clinical artery wave. The results show that when the subject is in a comfortable position with moderate physiological levels, the heartbeat has no connection whatsoever with blood pressure. The greatest heartbeat strain, which occurs when the veins and arteries respectively are being cleared, displays as a linear change.
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Tsai, Ming Chang, and Shyh Chour Huang. "The Analysis of Pulse Pressure by Vascular Strain." Applied Mechanics and Materials 268-270 (December 2012): 1194–97. http://dx.doi.org/10.4028/www.scientific.net/amm.268-270.1194.
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The objective of this paper is to use the Noninvasive Strain Measurement System to monitor the pulse pressure of the blood’s undulation in the artery as an index for the clinical diagnosis of arteriosclerosis. In the study, a strain-measuring device (350Ω) is affixed to the left side of the radial styloid process, on the surface of the skin, and is connected to the Strain FleXense. An artery-pressuring tape is set on the left humerus, and the measurement of the wavelength and frequency of the heartbeat is taken to compare with the clinical artery wave. The results show that when the subject is in a comfortable position with moderate physiological levels, the heartbeat has no connection whatsoever with blood pressure. The greatest heartbeat strain, which occurs when the veins and arteries respectively are being cleared, displays as a linear change.
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Nakagawa, Daichi, Kohsuke Kudo, Olatilewa Awe, Mario Zanaty, Yasunori Nagahama, Cameron Cushing, Vincent Magnotta, et al. "Detection of microbleeds associated with sentinel headache using MRI quantitative susceptibility mapping: pilot study." Journal of Neurosurgery 130, no. 4 (April 2019): 1391–97. http://dx.doi.org/10.3171/2018.2.jns1884.
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OBJECTSentinel headaches (SHs) associated with cerebral aneurysms (CAs) could be due to microbleeds, which are considered a sign that an aneurysm is unstable. Despite the prognostic importance of these microbleeds, they remain difficult to detect using routine imaging studies. The objective of this pilot study is to detect microbleeds associated with SH using a magnetic resonance imaging (MRI) quantitative susceptibility mapping (QSM) sequence and then evaluate the morphological characteristics of unstable aneurysms with microbleeds.METHODSTwenty CAs in 16 consecutive patients with an initial presentation of headache (HA) leading to a diagnosis of CA were analyzed. Headaches in 4 of the patients (two of whom had 2 aneurysms each) met the typical definition of SH, and the other 12 patients (two of whom also had 2 aneurysms each) all had migraine HA. All patients underwent imaging with the MRI-QSM sequence. Two independent MRI experts who were blinded to the patients’ clinical history performed 3D graphical analysis to evaluate for potential microbleeds associated with these CAs. Computational flow and morphometric analyses were also performed to estimate wall shear and morphological variables.RESULTSIn the 4 patients with SH, MRI-QSM results were positive for 4 aneurysms, and hence these aneurysms were considered positive for non-heme ferric iron (microbleeds). The other 16 aneurysms were negative. Among aneurysm shape indices, the undulation index was significantly higher in the QSM-positive group than in the QSM-negative group. In addition, the spatial averaged wall shear magnitude was lower in the aneurysm wall in direct contact with microbleeds.CONCLUSIONSMRI-QSM allows for objective detection of microbleeds associated with SH and therefore identification of unstable CAs. CAs with slightly greater undulation indices are associated with positive MRI-QSM results and hence with microbleeds. Studies with larger populations are needed to confirm these preliminary findings.
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Ercan, Fabian E. Z., Juha Mikola, Tarja Silfver, Kristiina Myller, Elina Vainio, Sandra Słowińska, Michał Słowiński, Mariusz Lamentowicz, Daan Blok, and Friederike Wagner-Cremer. "Effects of experimental warming on Betula nana epidermal cell growth tested over its maximum climatological growth range." PLOS ONE 16, no. 5 (May 19, 2021): e0251625. http://dx.doi.org/10.1371/journal.pone.0251625.
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Numerous long-term, free-air plant growth facilities currently explore vegetation responses to the ongoing climate change in northern latitudes. Open top chamber (OTC) experiments as well as the experimental set-ups with active warming focus on many facets of plant growth and performance, but information on morphological alterations of plant cells is still scarce. Here we compare the effects of in-situ warming on leaf epidermal cell expansion in dwarf birch, Betula nana in Finland, Greenland, and Poland. The localities of the three in-situ warming experiments represent contrasting regions of B. nana distribution, with the sites in Finland and Greenland representing the current main distribution in low and high Arctic, respectively, and the continental site in Poland as a B. nana relict Holocene microrefugium. We quantified the epidermal cell lateral expansion by microscopic analysis of B. nana leaf cuticles. The leaves were produced in paired experimental treatment plots with either artificial warming or ambient temperature. At all localities, the leaves were collected in two years at the end of the growing season to facilitate between-site and within-site comparison. The measured parameters included the epidermal cell area and circumference, and using these, the degree of cell wall undulation was calculated as an Undulation Index (UI). We found enhanced leaf epidermal cell expansion under experimental warming, except for the extremely low temperature Greenland site where no significant difference occurred between the treatments. These results demonstrate a strong response of leaf growth at individual cell level to growing season temperature, but also suggest that in harsh conditions other environmental factors may limit this response. Our results provide evidence of the relevance of climate warming for plant leaf maturation and underpin the importance of studies covering large geographical scales.
Dissertations / Theses on the topic "Undulation index"
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Duff, H. L. "Calibrating new isotopic and morphological tools for palaeoecological forest reconstructions." Thesis, 2017. http://hdl.handle.net/2440/126659.
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This item is only available electronically.The ability to identify forest architecture in the geologic past has implications for our understanding of palaeoecological processes. The degree of canopy closure (or density of foliage) effects atmospheric circulation and hydrologic cycling, which in turn, can influence terrestrial temperature and rainfall patterns. Closed canopy forests are characterised by strong gradients in light intensity, which influence the chemistry and morphology of leaves. This study has used isotopic and morphological leaf traits from the modern closed canopy Daintree Rainforest in Queensland, which can also be measured from fossil leaves, to calibrate a multiproxy tool that characterises the spatial distribution of light intensity. Leaf area index (LAI) was used to quantify forest canopy closure. Changes in carbon isotope ratios (δ13C), leaf mass per area (LMA), undulation index (UI) and cell area (CA) all had linear correlations with increasing LAI from the canopy to the understory. Therefore, these traits can be used as a proxy for reconstructions. However, the magnitude of responses varies between species. A portion of species were unresponsive in UI. Therefore, this proxy may not be suitable for all species. Traits from leaves from beneath a gap in canopy closure and those from a drought experiment, did not deviate from the general gradient seen with LAI. The model used to predict LMA (petiole width2/leaf area) did not correspond with measured LMA and did not characterise the light gradient found within the Daintree rainforest. However, they did predict the average LMA of the rainforest. Investigations into inter-trait variations demonstrate that δ13C, CA and UI correlate with LMA, and CA correlates with UI. Results show several new leaf traits that can be used to identify the degree of shading in closed canopy forests in the fossil record and demonstrate how light gradients drive variation within a forest.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 2017
Conference papers on the topic "Undulation index"
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Bush, Rosemary T., Ellen D. Currano, Bonnie F. Jacobs, Francesca A. McInerney, Regan E. Dunn, and Neil J. Tabor. "BRINGING LEAF SHADE PROXIES INTO THE LIGHT: WHAT DO UNDULATION INDEX AND LEAF δ13C MEAN IN A FOSSIL FOREST?" In GSA Annual Meeting in Seattle, Washington, USA - 2017. Geological Society of America, 2017. http://dx.doi.org/10.1130/abs/2017am-304746.
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Brands, Sjoerd, and Ross Lowdon. "Scaled Tortuosity Index: Quantification of Borehole Undulations in terms of Hole Curvature, Clearance and Pipe Stiffness." In IADC/SPE Drilling Conference and Exhibition. Society of Petroleum Engineers, 2012. http://dx.doi.org/10.2118/151274-ms.
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Cabezas-Rabadán, Carlos, Josep E. Pardo-Pascual, Jesús Palomar-Vázquez, and Alfonso Fernández-Sarría. "Monitoring the spatiotemporal variability of beach mesoforms by analyzing Sentinel-2 images." In 5th Joint International Symposium on Deformation Monitoring. Valencia: Editorial de la Universitat Politècnica de València, 2022. http://dx.doi.org/10.4995/jisdm2022.2022.13822.
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Beaches are extremely dynamic natural environments that experience significant variations at different spatial and temporal scales. The processes of appearance and maintenance of morphological features as the beach mesoforms, as well as their characterization, may provide useful information on the morphodynamic evolution of a beach and the spatial variability of nearshore processes. The high availability of Sentinel-2 satellite images together with the development of tools such as the system SHOREX allows the automatic extraction of the position of the shore. The high accuracy of the resulting satellite-derived shorelines (SDS) offers high potential for the definition of relatively detailed morphological features. This work assesses the ability to apply the SDS for characterizing beach mesoforms appearing at Cala de Mijas, in Málaga (S Spain) as well as characterising their changes over time. The extraction of the SDS enables the characterisation of rhythmic coastal forms through the undulations described by the shoreline position along the beach face by using a sinuosity index and to start to address the study of their relationship with the registered wave conditions. This proves that the information derived from mid-resolution satellite images can become a key source of information to characterize the morphological dynamics of beach environments.
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Liu, Wubo, Xiaofei Gao, Qingquan Li, Yi Guo, Lei Yu, Chao Wang, Botao Chang, Fei Wang, Shuzhong Li, and Yen Han Shim. "Enhancing Oil Recovery in a Brown Oilfield of Offshore South China." In Offshore Technology Conference Asia. OTC, 2022. http://dx.doi.org/10.4043/31365-ms.
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Abstract Located in offshore South China, XJ oil field entered the mature development phase after more than 20 years of production, with the water cut of the field increasing to 93%. A new strategy was executed starting in 2018 that targeted the remaining oil column, which was being squeezed by a strong bottomwater. One of the biggest challenges was the high uncertainty of the oil/water contacts in the current reservoir state. After reviewing the technical and geological challenges encountered, we will describe the successful approach taken to optimize the remaining reserves recovery using innovative horizontal well placement strategies. Using a few case studies, we will illustrate how we executed this innovative well placement strategy. This includes landing the horizontal wells at the upper part of the reservoir with low incident angle, drilling the horizontal sections close to the top of target zones using a reservoir boundary detection tool, and using a continuous packer for the well completion to reduce the water cut. In addition, we will describe how the team evaluated and selected logging technologies in the planning phase for proper well placement. The two cases discussed in this paper are based on horizontal wells completed using the following new strategy: maintaining a long lateral section in the upper layer of a predefined target, following the undulating structure while mapping the thin sandstone, keeping the trajectory in the target zone, etc. To ensure that each horizontal well could meet the target productivity index planned, real-time data were used in reservoir modeling to determine the required lateral length of each horizonal well. With the purpose of controlling water cut and improving oil recovery in these laterals, a new completion assembly, including a perforated liner with special completion material that prevented water from entering the liners, were installed in selected intervals according the logging data interpretation. Several observations will be highlighted, including: Real-time logging data can effectively evaluate the reservoir properties and structural changes along the lateral Optimum well placement in the lateral section is critical for draining the remaining oil column An optimized completion design based on real-time reservoir evaluation. The performance of the wells drilled to date shows that the production increased from 1,000 to 3,000 BOPD with zero to very low water cut. A reversing production trend from a declining trend to a growth trend is recorded. The successful implementation of the new strategy and the application of fit-for-purpose technologies in mature oil fields lead to improved production and increased oil recovery.