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Journal articles on the topic 'Pressure time integrals'

Author: Grafiati

Published: 4 June 2021

Last updated: 20 February 2023

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1

Claisse, Penny J., Jodi Binning, and Julia Potter. "Effect of Orthotic Therapy on Claw Toe Loading." Journal of the American Podiatric Medical Association 94, no. 3 (May 1, 2004): 246–54. http://dx.doi.org/10.7547/0940246.

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This study demonstrates the effect of orthotic therapy for toe deformity on toe and metatarsal head pressures using a new analysis method facilitated by an in-shoe pressure-measurement system’s ability to export detailed data. Plantar pressure–time integrals in 11 individuals (22 feet) with claw deformity of the lesser toes were measured with and without toe props. Differences in pressure–time integrals at every individual sensor unit were then calculated for the two conditions, and significance was tested using the paired t-test. Plantar surface charts with contours of equal significant press

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2

Naraghi, Reza, Linda Slack-Smith, and Alan Bryant. "Plantar Pressure Measurements and Geometric Analysis of Patients With and Without Morton’s Neuroma." Foot & Ankle International 39, no. 7 (April 11, 2018): 829–35. http://dx.doi.org/10.1177/1071100718766553.

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Background: The purpose of this research was to see if there were any differences in peak pressure, contact time, pressure-time integrals, and geometric variables such as forefoot width, foot length, coefficient of spreading, and arch index between subjects with Morton’s neuroma (MN) and control subjects. Methods: Dynamic peak plantar pressure, contact time, pressure-time integral, and geometric data were extracted using the EMED-X platform in 52 subjects with MN and 31 control subjects. Differences in peak pressure, contact time, pressure-time integral, and geometric data between participants

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Tong, Jasper W. K., U. Rajendra Acharya, Kuang C. Chua, and Peck H. Tan. "In-shoe Plantar Pressure Distribution in Nonneuropathic Type 2 Diabetic Patients in Singapore." Journal of the American Podiatric Medical Association 101, no. 6 (November 1, 2011): 509–16. http://dx.doi.org/10.7547/1010509.

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Background: We sought to establish the in-shoe plantar pressure distribution during normal level walking in type 2 diabetic patients of Chinese, Indian, and Malay descent without clinical evidence of peripheral neuropathy. Methods: Thirty-five patients with type 2 diabetes mellitus without loss of tactile sensation and foot deformities and 38 nondiabetic individuals in a control group had in-shoe plantar pressures collected. Maximum peak pressure and peak pressure-time integral of each foot were analyzed as separate variables and were masked into 13 areas. Differences in pressure variables wer

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4

Borg, Iona, Stephen Mizzi, and Cynthia Formosa. "Plantar Pressure Distribution in Patients with Diabetic Peripheral Neuropathy and a First-Ray Amputation." Journal of the American Podiatric Medical Association 108, no. 3 (May 1, 2018): 225–30. http://dx.doi.org/10.7547/16-021.

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Background: Elevated dynamic plantar pressures are a consistent finding in diabetic patients with peripheral neuropathy, with implications for plantar foot ulceration. This study aimed to investigate whether a first-ray amputation affects plantar pressures and plantar pressure distribution patterns in individuals living with diabetes and peripheral neuropathy. Methods: A nonexperimental matched-subject design was conducted. Twenty patients living with diabetes and peripheral neuropathy were recruited. Group 1 (n = 10) had a first-ray amputation and group 2 (n = 10) had an intact foot with no h

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Štefan, Lovro, Mario Kasović, and Martin Zvonar. "Association between the levels of physical activity and plantar pressure in 6-14-year-old children." PeerJ 8 (February 14, 2020): e8551. http://dx.doi.org/10.7717/peerj.8551.

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Background The main purpose of the study was to determine whether lower levels of physical activity were associated with higher plantar pressure generated under each foot. Methods In this cross-sectional study, we recruited 641 children aged 6–14 years (agemean ± SD = 9.7 ± 2.4 years; heightmean ± SD = 143.6 ± 15.3 cm, weightmean ± SD = 37.6 ± 13.4 kg; body-mass indexmean ± SD = 17.6 ± 3.2 kg/m2; 44.2% girls). We used EMED –XL pressure platform to measure force time integral, pressure-time integral, contact-time and contact area, peak plantar pressure and mean plantar pressure of the right and

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Chang, An-Hsiung, Ziad U. Abu-Faraj, Gerald F. Harris, Joe Nery, and Michael J. Shereff. "Multistep Measurement of Plantar Pressure Alterations Using Metatarsal Pads." Foot & Ankle International 15, no. 12 (December 1994): 654–60. http://dx.doi.org/10.1177/107110079401501205.

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Metatarsal pads are frequently prescribed for nonoperative management of metatarsalgia due to various etiologies. When appropriately placed, they are effective in reducing pressures under the metatarsal heads on the plantar surface of the foot. Despite the positive clinical reports that have been cited, there are no quantitative studies documenting the load redistribution effects of these pads during multiple step usage within the shoe environment. The objective of this study was to assess changes in plantar pressure metrics resulting from pad use. Ten normal adult male subjects were tested du

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Prats, Michael, Lidia Lucely Meneses-P., Fernando Samaniego-V., and Ricardo Pacheco-V. "Pressure Buildup in a Well Produced at Constant Pressure." SPE Journal 25, no. 04 (May 20, 2020): 1578–98. http://dx.doi.org/10.2118/201111-pa.

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Summary Dimensionless analytic expressions of the well-pressure buildup resulting from shutting in a well after producing it at constant pressure were obtained, in both Laplace space and time, using different mathematical approaches to solve the pertinent differential equations, including the effects of both wellbore storage and skin damage. Such a pressure response is said to have been obtained at constant-pressure-buildup (CPBU) conditions. The well, represented by a cylindrical source of nonzero radius, produces a single compressible fluid from an infinite and homogeneous reservoir. For a v

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8

Maiwald, Christian, Stefan Grau, Inga Krauss, Marlene Mauch, Detlef Axmann, and Thomas Horstmann. "Reproducibility of Plantar Pressure Distribution Data in Barefoot Running." Journal of Applied Biomechanics 24, no. 1 (February 2008): 14–23. http://dx.doi.org/10.1123/jab.24.1.14.

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The aim of this study was to provide detailed information on rationales, calculations, and results of common methods used to quantify reproducibility in plantar pressure variables. Recreational runners (N = 95) performed multiple barefoot running trials in a laboratory setup, and pressure variables were analyzed in nine distinct subareas of the foot. Reproducibility was assessed by calculating intraclass correlation coefficients (ICC) and the root mean square error (RMSE). Intraclass correlation coefficients ranged from 0.58 to 0.99, depending on the respective variable and type of ICC. Root m

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9

Rome, Keith, David George Survepalli, Maria Lobo, Nicola Dalbeth, Fiona McQueen, and Peter J. McNair. "Evaluating Intratester Reliability of Manual Masking of Plantar Pressure Measurements Associated with Chronic Gout." Journal of the American Podiatric Medical Association 101, no. 5 (September 1, 2011): 424–29. http://dx.doi.org/10.7547/1010424.

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Background: Plantar pressure measurements are commonly used to evaluate foot function in chronic musculoskeletal conditions. However, manually identifying anatomical landmarks is a source of measurement error and can produce unreliable data. The aim of this study was to evaluate intratester reliability associated with manual masking of plantar pressure measurements in patients with gout. Methods: Twenty-five patients with chronic gout (mean disease duration, 22 years) were recruited from rheumatology outpatient clinics. Patients were excluded if they were experiencing an acute gout flare at th

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Coates, P. D., and R. G. Speight. "Towards Intelligent Process Control of Injection Moulding of Polymers." Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture 209, no. 5 (October 1995): 357–67. http://dx.doi.org/10.1243/pime_proc_1995_209_095_02.

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Steps towards process control of the complex, multi-variable injection moulding process are presented. In-process measurements, in particular melt and hydraulic pressures in the primary injection stage, are shown to provide a sensitive means of monitoring changes in the process and changes in the polymer feedstock. Correlations have been observed between real time process measurements, in the form of specific time integrals of melt and hydraulic pressure, and product quality measures, such as product weight or dimensions. The research has been validated in both scientific laboratory and factor

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Borodin, Vladislav I., Alexandr V. Lun-Fu, Mikhail A. Bubenchikov, Alexey M. Bubenchikov, and Dmitriy V. Mamontov. "Exact solution of the fundamental equation of acoustics for a pressure wave developing in two directions." Vestnik Tomskogo gosudarstvennogo universiteta. Matematika i mekhanika, no. 79 (2022): 5–13. http://dx.doi.org/10.17223/19988621/79/1.

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The authors proceed from the hyperbolic equation for acoustic pressure. Using the integral Fourier transform along the axial coordinate, an equation in partial derivatives for the kernel of this transformation is found. This equation contains only one spatial coordinate and time. Applying the integral Laplace transform in time to the last equation, we obtain an ordinary differential equation with respect to the radial coordinate for the corresponding image. It turns out that the solution of the last equation is the well-known Macdonald function. For this function, it was possible to find the o

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Klein, Erin E., Ryan T. Crews, Stephanie C. Wu, James S. Wrobel, and David G. Armstrong. "CLEAR Cleat: A Proof-of-Concept Trial of an Aerobic Activity Facilitator to Reduce Plantar Forefoot Pressures and Their Potential in Those with Foot Ulcers." Journal of the American Podiatric Medical Association 98, no. 4 (July 1, 2008): 261–67. http://dx.doi.org/10.7547/0980261.

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Background: Exercise has not been studied extensively in persons with active neuropathic diabetic foot wounds, primarily because a device does not exist that allows patients to exercise while sufficiently off-loading pressure at the ulcer site. The purpose of this project was to demonstrate a device that reduces cycling plantar forefoot pressure. Methods: Ten healthy participants rode a recumbent bicycle under three cycling conditions. While the left foot interaction remained constant with a standard gym shoe and pedal, the right foot was exposed to a control condition with standard gym shoe a

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Otter, Simon J., Catherine Jane Bowen, and Adam K. Young. "Forefoot Plantar Pressures in Rheumatoid Arthritis." Journal of the American Podiatric Medical Association 94, no. 3 (May 1, 2004): 255–60. http://dx.doi.org/10.7547/0940255.

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We sought to investigate the magnitude and duration of peak forefoot plantar pressures in rheumatoid arthritis. The spatial and temporal characteristics of forefoot plantar pressures were measured in 25 patients with a positive diagnosis of rheumatoid arthritis of 5 to 10 years’ duration (mean, 8 years) and a comparison group using a platform-based pressure-measurement system. There were no significant differences between groups in the magnitude of peak plantar pressure in the forefoot region. Significant differences were, however, noted for temporal aspects of foot-pressure measurement. The d

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14

Chong, Thomas S. Y., William R. Paterson, and David M. Scott. "An Improved Method to Calculate the Conservation of Mass in the Simulation of Rapid Pressurization Depressurization in a Packed Bed." ASEAN Journal of Chemical Engineering 2, no. 1 (October 20, 2008): 30. http://dx.doi.org/10.22146/ajche.50800.

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The work described here forms part of a project to model rapid pressure swing adsorption (RPSA), which is a single-bed process used for air separation. We have earlier identified a form of model and boundary conditions for an axially dispersed plug flow model that conserves mass. We solve the RPSA models numerically by spatially discretizing the partial differential equations to a system of ordinary differential equations (ODEs), which are then integrated over time. Although the formulation of our models conserves mass, our numerical simulations, however, do not perfectly conserve mass because

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15

Wegener, Caleb, Joshua Burns, Stefania Penkala, and Grad Dip Ex Spr Sc. "Effect of Neutral-Cushioned Running Shoes on Plantar Pressure Loading and Comfort in Athletes with Cavus Feet." American Journal of Sports Medicine 36, no. 11 (June 24, 2008): 2139–46. http://dx.doi.org/10.1177/0363546508318191.

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Background High injury rates observed in athletes with cavus feet are thought to be associated with elevated plantar pressure loading. Neutral-cushioned running shoes are often recommended to manage and prevent such injuries. Purpose To investigate in-shoe plantar pressure loading and comfort during running in 2 popular neutral-cushioned running shoes recommended for athletes with cavus feet. Study Design Controlled laboratory study. Methods Plantar pressures were collected using the in-shoe Novel Pedar-X system during overground running in 22 athletes with cavus feet in 2 neutral-cushioned ru

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16

Afinogentov, Alexander A., and Yulia A. Tychinina. "Analytical solution of the boundary value problem of mathematical modeling for non-stationary oil flows through the trunk pipeline in the presence of internal pressure sources." Vestnik of Samara State Technical University. Technical Sciences Series 30, no. 4 (February 1, 2023): 6–19. http://dx.doi.org/10.14498/tech.2022.4.1.

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The main oil pipeline, due to its spatial extent, can be considered as a control object with distributed parameters (ODP). The dependences on time and coordinates of the flow velocity and pressure in the pipeline are considered as controlled output values of the ODP. The boundary value problem of mathematical modeling of the process of pipeline transportation of oil in the standard form is presented in the form of a linear partial differential equation of the second order. The paper presents a solution to the boundary value problem of mathematical modeling of unsteady oil flow through a trunk

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Sacco, Isabel C. N., Tatiana Almeida Bacarin, Maíra Grizzo Canettieri, and Ewald M. Hennig. "Plantar Pressures During Shod Gait in Diabetic Neuropathic Patients with and without a History of Plantar Ulceration." Journal of the American Podiatric Medical Association 99, no. 4 (July 1, 2009): 285–94. http://dx.doi.org/10.7547/0980285.

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Background: Diabetic neuropathy leads to progressive loss of sensation, lower-limb distal muscle atrophy, autonomic impairment, and gait alterations that overload feet. This overload has been associated with plantar ulcers even with consistent daily use of shoes. We sought to investigate and compare the influence of diabetic neuropathy and plantar ulcers in the clinical history of diabetic neuropathic patients on plantar sensitivity, symptoms, and plantar pressure distribution during gait while patients wore their everyday shoes. Methods: Patients were categorized into three groups: a control

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18

CHOU, YOU-LI, SHIUH-SHENG SHI, GWO-FENG HUANG, and TING-SHENG LIN. "INTERFACE PRESSURE AND GAIT ANALYSIS IN DIFFERENT WALKING SPEEDS AND ON THE BELOW-KNEE AMPUTEES WITH MULTIPLE AXIS PROSTHETIC FOOT PROSTHESIS." Biomedical Engineering: Applications, Basis and Communications 15, no. 05 (October 25, 2003): 207–11. http://dx.doi.org/10.4015/s1016237203000316.

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Interface stresses are an important consideration in stump and socket for a prosthetic limb to a person with transtibial amputation. During stance phase of the gait cycle, the prosthetic socket is expected to support and distribute the entire body weight of the patient. Excessive stresses between stump and socket will induce pain, discomfort and breakdown of soft tissues. The objectives of this study are to investigate the differences of gait, the maximum forces and pressures between stump and socket during different walking speed. Motion analysis system was applied to investigate the kinemati

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19

Azmoudeh, S., H. Zamani, and K. Shelesh-Nezhad. "Influence of Injection Molding Parameters on the Consistency of Molding Process." Applied Mechanics and Materials 446-447 (November 2013): 398–402. http://dx.doi.org/10.4028/www.scientific.net/amm.446-447.398.

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The existence of variations in the injection molding process conditions leads to the inconsistency of molded parts quality during the molding cycles. In this research, the variations of cavity pressure-time profiles integrals over the molding cycles were accounted as the molded parts quality variations. Thereafter, the correlations between injection molding process settings and the degree of consistency of molding process were investigated by applying cavity pressure measurement, Taguchi design of experiments approach and signal to noise ratio. The results derived from experiments indicated th

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Khokhlov, A. V. "EXACT SOLUTION FOR THE STRESS RELAXATION PROBLEM IN A THICKWALLED TUBE OF A NONLINEAR VISCOELASTIC MATERIAL OBEYING THE RABOTNOV CONSTITUTIVE EQUATION." Problems of Strength and Plasticity 84, no. 2 (2022): 168–91. http://dx.doi.org/10.32326/1814-9146-2022-84-2-168-191.

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We constructed and studied analytically the exact solution of the quasi-static boundary value problem for a hollow cylinder (a tube) made of physically nonlinear homogeneous isotropic viscoelastic material obeying the Rabotnov constitutive equation with two arbitrary material functions (a creep compliance and a function which governs physical nonlinearity). A time-dependent displacement and zero shear stresses are given on the inside cylinder surface, a pressure (normal stress) is given on outside surface and zero axial displacements and zero shear stresses are preset on the end cross sections

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Khokhlov, A. V. "THE EXACT SOLUTION FOR STRAINS AND STRESSES IN A HOLLOW CYLINDER OF NON-LINEAR VISCOELASTIC MATERIAL SUBJECT TO INTERNAL AND EXTERNAL PRESSURES IN THE CASE OF POWER MATERIAL FUNCTION GOVERNING NON-LINEARITY." Problems of strenght and plasticity 82, no. 2 (2020): 225–43. http://dx.doi.org/10.32326/1814-9146-2020-82-2-225-243.

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We study analytically the exact solution of the quasi-static problem for a thick-walled tube of physically non-linear viscoelastic material obeying the Rabotnov constitutive equation with two arbitrary material functions (a creep compliance and a function which governs physical non-linearity). We suppose that a material is homogeneous, isotropic and incompressible and that a tube is loaded with time-dependent internal and external pressures (varying slowly enough to neglect inertia terms in the equilibrium equations) and that a plain strain state is realized, i.e. zero axial displacements are

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Zhang, Hui, Xin Zhang, Yi Shang, Giri Kattel, and Lijuan Miao. "Continuously Vegetation Greening over Inner Mongolia for the Past Three Decades." Remote Sensing 13, no. 13 (June 23, 2021): 2446. http://dx.doi.org/10.3390/rs13132446.

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The warming climate has rapidly altered vegetation growth in drylands, and consequently, has put great pressure on sustainable livelihoods. Various datasets have been applied from local to global scale to study vegetation dynamics and there is a lack of solid comparison among multiple datasets. Note that vegetation growth might shift over time and the greening and browning components over a long-time span might be masked by a linear trend. Here, we aim to monitor the long-term and nonlinear dynamics in vegetation greenness for Inner Mongolia (an important part of dryland Asia). As a useful too

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Vypasnyak, Ihor, Bogdan Mytskan, Serhiy Popel, Tetyana Mytskan, Iryna Ivanyshyn, Volodymyr Banakh, Lyubov Levandovska, and Viktoria Gryb. "Non-medicinal Correction of Motor Disorders of the Valley of the Foot in Multiple Sclerosis." Acta Balneologica 63, no. 1 (2021): 26–32. http://dx.doi.org/10.36740/abal202101104.

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Introduction: Analysis of motor disorders peculiarities in multiple sclerosis and assessment of non-drug correction and rehabilitation procedures impact on them will help to form new approaches in studying the motor disorders mechanisms, expand diagnostic capabilities and optimize physical therapy programs, which determines the relevance of our study. Aim: To analyze gait disorders in patients with multiple sclerosis associated with increased skeletal muscle tone, which form the anterior and posterior myofascial kinematic leg chain and to carry out their non-drug correction. Material and Metho

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Marston, Philip L., Timothy D. Daniel, Auberry R. Fortuner, Ivars P. Kirsteins, and Ahmad T. Abawi. "Amplitude and time-dependence of ultrasonic radiation force on modulation frequency computed from specular reflection contributions." Journal of the Acoustical Society of America 151, no. 4 (April 2022): A89. http://dx.doi.org/10.1121/10.0010749.

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Ever since the late 1970s, there has been interest in the modulated radiation pressure of double sideband suppressed carrier (DSSC) ultrasound, because the associated radiation pressure oscillates at a single low frequency. Recent research considers situations, where the radius of curvature of the illuminated objects greatly exceeds the wavelength at the implicit carrier frequency of the ultrasonic illumination [Marston et al., J. Acoust. Soc. Am. 149, 3042–3051 (2021); 150, 25–28 (2021)]. Furthermore, the objects of interest, cylinders, and spheres in water are taken to be sufficiently highly

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Guenette, Jordan A., Lee M. Romer, Jordan S. Querido, Romeo Chua, Neil D. Eves, Jeremy D. Road, Donald C. McKenzie, and A. William Sheel. "Sex differences in exercise-induced diaphragmatic fatigue in endurance-trained athletes." Journal of Applied Physiology 109, no. 1 (July 2010): 35–46. http://dx.doi.org/10.1152/japplphysiol.01341.2009.

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There is evidence that female athletes may be more susceptible to exercise-induced arterial hypoxemia and expiratory flow limitation and have greater increases in operational lung volumes during exercise relative to men. These pulmonary limitations may ultimately lead to greater levels of diaphragmatic fatigue in women. Accordingly, the purpose of this study was to determine whether there are sex differences in the prevalence and severity of exercise-induced diaphragmatic fatigue in 38 healthy endurance-trained men ( n = 19; maximal aerobic capacity = 64.0 ± 1.9 ml·kg−1·min−1) and women ( n =

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Zhang, Guoxin, Duo Wai-Chi Wong, Ivy Kwan-Kei Wong, Tony Lin-Wei Chen, Tommy Tung-Ho Hong, Yinghu Peng, Yan Wang, Qitao Tan, and Ming Zhang. "Plantar Pressure Variability and Asymmetry in Elderly Performing 60-Minute Treadmill Brisk-Walking: Paving the Way towards Fatigue-Induced Instability Assessment Using Wearable In-Shoe Pressure Sensors." Sensors 21, no. 9 (May 6, 2021): 3217. http://dx.doi.org/10.3390/s21093217.

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Evaluation of potential fatigue for the elderly could minimize their risk of injury and thus encourage them to do more physical exercises. Fatigue-related gait instability was often assessed by the changes of joint kinematics, whilst planar pressure variability and asymmetry parameters may complement and provide better estimation. We hypothesized that fatigue condition (induced by the treadmill brisk-walking task) would lead to instability and could be reflected by the variability and asymmetry of plantar pressure. Fifteen elderly adults participated in the 60-min brisk walking trial on a trea

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Escobar, Freddy Humberto, Javier Andrés Martínez, and Matilde Montealegre M. "PRESSURE AND PRESSURE DERIVATIVE ANALYSIS FOR INJECTION TESTS WITH VARIABLE TEMPERATURE WITHOUT TYPE-CURVE MATCHING." CT&F - Ciencia, Tecnología y Futuro 3, no. 4 (December 31, 2008): 83–91. http://dx.doi.org/10.29047/01225383.464.

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The analysis of injection tests under nonisothermic conditions is important for the accurate estimation of the reservoir permeability and the well's skin factor; since previously an isothermical system was assumed without taking into account a moving temperature front which expands with time plus the consequent changes in both viscosity and mobility between the cold and the hot zone of the reservoir which leads to unreliable estimation of the reservoir and well parameters. To construct the solution an analytical approach presented by Boughrara and Peres (2007) was used. That solution was initi

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Petrov, A. N., and M. V. Grigoryev. "NUMERICAL MODELLING OF DYNAMIC RESPONSE OF A PARTIALLY SATURATED POROELASTIC HALF-SPACE IN CASE OF A LOAD ACTING INSIDE A CUBIC CAVITY." Problems of strenght and plasticity 82, no. 4 (2020): 507–23. http://dx.doi.org/10.32326/1814-9146-2020-82-4-507-523.

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Computer modeling based on the boundary element method is performed for the problem of loading in terms of the Heaviside step function inside a cubic cavity located in a partially saturated poroelastic half-space. A poroelastic medium is represented by a heterogeneous material-based model consisting of an elastic matrix phase and two phases of fillers – liquid and gas filling the pore system. The material model corresponds to a three-component medium. The constitutive relations of poroelastic medium written in terms skeleton displacements and pore pressures of fillers are considered. The origi

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Hughes, Chris W., Shane Elipot, Miguel Ángel Morales Maqueda, and John W. Loder. "Test of a Method for Monitoring the Geostrophic Meridional Overturning Circulation Using Only Boundary Measurements." Journal of Atmospheric and Oceanic Technology 30, no. 4 (April 1, 2013): 789–809. http://dx.doi.org/10.1175/jtech-d-12-00149.1.

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Abstract Measurements of ocean bottom pressure, particularly on the continental slope, make an efficient means of monitoring large-scale integrals of the ocean circulation. However, direct pressure measurements are limited to monitoring relatively short time scales (compared to the deployment period) because of problems with sensor drift. Measurements are used from the northwest Atlantic continental slope, as part of the Rapid Climate Change (RAPID)–West Atlantic Variability Experiment, to demonstrate that the drift problem can be overcome by using near-boundary measurements of density and vel

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Venner, C. H., W. E. ten Napel, and R. Bosma. "Advanced Multilevel Solution of the EHL Line Contact Problem." Journal of Tribology 112, no. 3 (July 1, 1990): 426–31. http://dx.doi.org/10.1115/1.2920277.

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The application of multilevel multi-integration to the calculation of the elastic deformation integrals and the use of an alternative relaxation process in the multilevel solution of the governing equations have resulted in an algorithm solving the EHL line contact problem in O(n ln n) operations, also for highly loaded situations. The reduction in computing time thus obtained was used to solve the problem using large numbers of nodal points and to study the pressure spike. The presented algorithm will enable fast and accurate solution of surface roughness and transient problems.

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VanZant, R. Scott, Thomas G. McPoil, and Mark W. Cornwall. "Symmetry of Plantar Pressures and Vertical Forces in Healthy Subjects During Walking." Journal of the American Podiatric Medical Association 91, no. 7 (July 1, 2001): 337–42. http://dx.doi.org/10.7547/87507315-91-7-337.

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The purpose of this study was to determine the degree of symmetry for in-shoe plantar pressure and vertical force patterns between the left and right feet of healthy subjects during walking. Thirty subjects with a mean age of 29.6 years participated in the study. Each subject walked a distance of 8 m three times while in-shoe plantar pressure and vertical force data were collected. A total of 12 steps were analyzed for both feet, and maximum vertical force, peak pressure, and pressure-time integrals were calculated for four plantar regions of the foot. No differences in the three variables wer

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SJÖGREN, TORBJÖRN, and ARNE V. JOHANSSON. "Measurement and modelling of homogeneous axisymmetric turbulence." Journal of Fluid Mechanics 374 (November 10, 1998): 59–90. http://dx.doi.org/10.1017/s0022112098002511.

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A new method for determining the slow and rapid pressure-strain rate terms directly from wind-tunnel experiments has been developed with the aid of a newly developed theoretical description of the kinematics of homogeneous axisymmetric turbulence. Both the straining and the return-to-isotropy process of homogeneous axisymmetric turbulence are studied with the aim of improving Reynolds stress closures. Direct experimental determination of the different terms in the transport equation for the Reynolds stress tensor plays a major role in the validation and development of turbulence models. For th

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Ogbue, M. C., and E. Steve Adewole. "Theoretical Investigation of Factors Affecting Water Breakthrough Time in a Horizontal Well Subject to Bottom Water Drive." Advanced Materials Research 824 (September 2013): 394–400. http://dx.doi.org/10.4028/www.scientific.net/amr.824.394.

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Water breakthrough marks end of economic life of a reservoir. It has negative influence on recovery, operations, and economics. This means that delaying the encroachment and production of water is a means of maximizing the ultimate oil recovery, operating at higher efficiency and maximizing profit. This theoretical research is aimed at solving for time water will breakthrough a horizontal well placed in bottom-water reservoir. And subsequently, suggest ways to delay the water breakthrough time. Thus the model herein is a repository of three aims of reservoir modeling; predict, optimize and mon

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Belevtsov, N. S. "On a Space-Fractional Generalization of the Black Oil Model." Mathematics and Mathematical Modeling, no. 6 (April 28, 2021): 13–27. http://dx.doi.org/10.24108/mathm.0620.0000228.

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Classical multiphase filtration models, which are based on Darcy's law, are well studied and actively used in modern oil engineering. However, such models do not allow efficient describing of processes with power-law memory effects or with spatial non-locality effects. In recent years, there has been a significantly increasing interest in models with fractional derivatives and integrals that allow such effects to be taken into account.The article considers the space-fractional generalization of the two-phase Black Oil model. This model is built on the basis of a fractional modification of the

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Vasconcelos, Ivan. "Source-receiver, reverse-time imaging of dual-source, vector-acoustic seismic data." GEOPHYSICS 78, no. 2 (March 1, 2013): WA123—WA145. http://dx.doi.org/10.1190/geo2012-0300.1.

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Novel technologies in seismic data acquisition allow for recording full vector-acoustic (VA) data: pointwise recordings of pressure and its multicomponent gradient, excited by pressure only as well as dipole/gradient sources. Building on recent connections between imaging and seismic interferometry, we present a wave-equation-based, nonlinear, reverse-time imaging approach that takes full advantage of dual-source multicomponent data. The method’s formulation relies on source-receiver scattering reciprocity, thus making proper use of VA fields in the wavefield extrapolation and imaging conditio

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Wong, Sen, and Manwai Yuen. "Blowup Phenomena for the Compressible Euler and Euler-Poisson Equations with Initial Functional Conditions." Scientific World Journal 2014 (2014): 1–5. http://dx.doi.org/10.1155/2014/580871.

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We study, in the radial symmetric case, the finite time life span of the compressible Euler or Euler-Poisson equations inRN. For timet≥0, we can define a functionalH(t)associated with the solution of the equations and some testing functionf. When the pressure functionPof the governing equations is of the formP=Kργ, whereρis the density function,Kis a constant, andγ>1, we can show that the nontrivialC1solutions with nonslip boundary condition will blow up in finite time ifH(0)satisfies some initial functional conditions defined by the integrals off. Examples of the testing functions includer

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Markvart, Jakob, Eva Rosenqvist, Helle Sørensen, Carl-Otto Ottosen, and Jesper M. Aaslyng. "Canopy Photosynthesis and Time-of-day Application of Supplemental Light." HortScience 44, no. 5 (August 2009): 1284–90. http://dx.doi.org/10.21273/hortsci.44.5.1284.

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There is increasing use of electricity for supplemental lighting in the northern European greenhouse industry. One reason for this may be to secure a high growth rate during low-light periods by an attempt to increase net photosynthesis. We wanted to clarify which period of the day resulted in the best use of a 5-h supplemental light period for photosynthesis and growth. The periods tested were supplemental light during the night, day, morning, and evening. The experiments were carried out in daylight climate chambers measuring canopy gas exchange. The air temperature was 25 °C and the CO2 lev

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Ostrikov, N. N., and E. M. Zhmulin. "Vortex dynamics of viscous fluid flows. Part 1. Two-dimensional flows." Journal of Fluid Mechanics 276 (October 10, 1994): 81–111. http://dx.doi.org/10.1017/s0022112094002478.

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The method of product integration is applied to the vortex dynamics of two-dimensional incompressible viscous media. In the cases of both unbounded and bounded flows under the no-slip boundary condition, the analytic solutions of the Cauchy problem are obtained for the Helmholtz equation in the form of linear and nonlinear product integrals. The application of product integrals allows the generalization in a natural way of the vortex dynamics concept to the case of viscous flows. However, this new approach requires the reconsideration of some traditional notions of vortex dynamics. Two lengths

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Pagel, Paul S., Douglas A. Hettrick, Judy R. Kersten, Dermot Lowe, and David C. Warltier. "Cardiovascular Effects of Propofol in Dogs with Dilated Cardiomyopathy." Anesthesiology 88, no. 1 (January 1, 1998): 180–89. http://dx.doi.org/10.1097/00000542-199801000-00026.

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Background The authors tested the hypothesis that propofol improves left ventricular diastolic function in dogs with dilated cardiomyopathy by reducing left ventricular preload and afterload. Methods Seven dogs were instrumented for left ventricular and aortic pressures, aortic blood flow, and subendocardial segment length. Left ventricular afterload and contractility were quantified with aortic input impedance and preload recruitable stroke work, respectively. Diastolic function was evaluated with a time constant of left ventricular relaxation (tau); segment-lengthening velocities and time-ve

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Zhang, Zhiwang, Yu Zhang, Weijie Fu, Zhen Wei, Jiayi Jiang, and Lin Wang. "Plantar Loads of Habitual Forefoot Strikers during Running on Different Overground Surfaces." Applied Sciences 10, no. 7 (March 26, 2020): 2271. http://dx.doi.org/10.3390/app10072271.

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The objective of this study is to investigate plantar loads characteristics of habitual forefoot strike runners while running on different surfaces. Twenty-six runners (age: 28.2 ± 6.8 y, height: 172.9 ± 4.1 cm, weight: 67.7 ± 9.6 kg, BMI (body mass index): 22.6 ± 2.8 kg/m2, running age: 5.0 ± 4.2 y, running distance per week: 14.6 ± 11.7 km) with habitual forefoot strike participated in the study. Runners were instructed to run at 3.3 ± 0.2 m/s on three surfaces: grass, synthetic rubber and concrete. An in-shoe pressure measurement system was used to collect and analyze plantar loads data. Ru

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Hope, Sarah A., David B. Tay, Ian T. Meredith, and James D. Cameron. "Comparison of generalized and gender-specific transfer functions for the derivation of aortic waveforms." American Journal of Physiology-Heart and Circulatory Physiology 283, no. 3 (September 1, 2002): H1150—H1156. http://dx.doi.org/10.1152/ajpheart.00216.2002.

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Arterial transfer functions have been promoted for the derivation of central aortic waveform characteristics not usually accessible noninvasively, but possibly of prognostic significance. The utility of generalized rather than gender-specific transfer functions has not been assessed. Invasive central aortic and noninvasive radial (Millar Mikro-tip tonometer) blood pressure waveforms were recorded simultaneously in 78 subjects (61 male and 17 female). Average transfer functions were obtained for the whole group and for each gender by two methods. Reverse transformation was performed with the us

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Pagel, Paul S., Dermot Lowe, Douglas A. Hettrick, Iyad N. Jamali, Judy R. Kersten, John P. Tessmer, and David C. Warltier. "Isoflurane, but Not Halothane, Improves Indices of Diastolic Performance in Dogs with Rapid Ventricular, Pacing-induced Cardiomyopathy." Anesthesiology 85, no. 3 (September 1, 1996): 644–54. http://dx.doi.org/10.1097/00000542-199609000-00025.

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Background The left ventricular (LV) mechanical effects of isoflurane and halothane were examined in dogs with rapid LV pacing-induced cardiomyopathy. These experiments tested the hypothesis that isoflurane and halothane differentially enhance indices of diastolic performance in dogs with moderate LV dysfunction. Methods Eight dogs were chronically instrumented for measurement of LV and aortic pressures, subendocardial segment length, and cardiac output. Contractility was quantified by preload recruitable stroke work (Mw). Diastolic function was evaluated with a time constant of isovolumic rel

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Liu, Shuangbiao, Michael J. Rodgers, Qian Wang, and Leon M. Keer. "A Fast and Effective Method for Transient Thermoelastic Displacement Analyses." Journal of Tribology 123, no. 3 (June 29, 2000): 479–85. http://dx.doi.org/10.1115/1.1308010.

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Frictional heating due to the relative motion of contacting surfaces causes temperature rise and thermal distortion, which in turn affects the contact geometry and pressure distribution. A fast and effective method is presented for the calculation of the normal surface displacement of an elastic halfspace due to arbitrary transient surface heating. The method uses Fourier-transformed Green’s functions (frequency response functions), found in the closed form by using the approach of Seo and Mura and the heat conduction analyses of Carslaw and Jaeger. The frequency response functions are shown a

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WEBB, G. M., G. P. ZANK, R. H. BURROWS, and R. E. RATKIEWICZ. "Alfvén simple waves." Journal of Plasma Physics 77, no. 1 (February 4, 2010): 51–93. http://dx.doi.org/10.1017/s0022377809990596.

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AbstractMulti-dimensional Alfvén simple waves in magnetohydrodynamics (MHD) are investigated using Boillat's formalism. For simple wave solutions, all physical variables (the gas density, pressure, fluid velocity, entropy, and magnetic field induction in the MHD case) depend on a single phase function ϕ, which is a function of the space and time variables. The simple wave ansatz requires that the wave normal and the normal speed of the wave front depend only on the phase function ϕ. This leads to an implicit equation for the phase function and a generalization of the concept of a plane wave. W

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GUO, Y. P. "Application of the Ffowcs Williams/Hawkings equation to two-dimensional problems." Journal of Fluid Mechanics 403 (January 25, 2000): 201–21. http://dx.doi.org/10.1017/s0022112099006989.

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This paper discusses the application of the Ffowcs Williams/Hawkings equation to two-dimensional problems. A two-dimensional version of this equation is derived, which not only provides a very efficient way for numerical implementation, but also reveals explicitly the features of the source mechanisms and the characteristics of the far-field noise associated with two-dimensional problems. It is shown that the sources can be interpreted, similarly to those in three-dimensional spaces, as quadrupoles from turbulent flows, dipoles due to surface pressure fluctuations on the bodies in the flow and

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Liu, Shuangbiao, and Qian Wang. "Transient Thermoelastic Stress Fields in a Half-Space." Journal of Tribology 125, no. 1 (December 31, 2002): 33–43. http://dx.doi.org/10.1115/1.1501087.

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Computing the thermoelastic stress field of a material subjected to frictional heating is essential for component failure prevention and life prediction. However, the analysis for three-dimensional thermoelastic stress field for tribological problems is not well developed. Furthermore, the pressure distribution due to rough surface contact is irregular; hence the frictional heating can hardly be described by an analytical expression. This paper presents a novel set of frequency-domain expressions (frequency response functions) of the thermoelastic stress field of a uniformly moving three-dimen

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Darbani, Mohsen. "The Meshfree Finite Element Method for Fluids with Large Deformations." Defect and Diffusion Forum 326-328 (April 2012): 176–80. http://dx.doi.org/10.4028/www.scientific.net/ddf.326-328.176.

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The shallow water equations (SWE) is often simulated by using Eulerian descriptions. These phenomena may give rise to strong gradients and lead to large distortion of grids meshes. Hence classical finite elements methods may fall in simulating such problems. In this paper we present a meshless method, based on the natural element nethod (NEM). In a geometrical domain of a cloud of nodes, NEM uses the Voronoi cells and then its dual, namely Delaunay triangulation. Its main advantage lies in shape function of the natural neighbour interpolation, such that the position of natural neighbours is en

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QUÉGUINER, CHRISTOPHE, and DOMINIQUE BARTHÈS-BIESEL. "Axisymmetric motion of capsules through cylindrical channels." Journal of Fluid Mechanics 348 (October 10, 1997): 349–76. http://dx.doi.org/10.1017/s0022112097006587.

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A boundary integral method is used to model the flow of capsules into pores. An axisymmetric configuration is considered where the capsule and the pore axis coincide. The channel is a cylinder with hyperbolic entrance and exit regions. The capsule has a discoidal unstressed shape, is filled with a Newtonian liquid and is enclosed by a very thin membrane with various elastic properties (neo-Hookean or area-incompressible). The motion of the internal capsule liquid and of the suspending fluid is governed by the Stokes equations whose solution is expressed as boundary integrals. Those are compute

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ISAZA, JUAN C., and LANCE R. COLLINS. "On the asymptotic behaviour of large-scale turbulence in homogeneous shear flow." Journal of Fluid Mechanics 637 (September 17, 2009): 213–39. http://dx.doi.org/10.1017/s002211200999053x.

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The asymptotic behaviour of large-scale velocity statistics in an homogeneous turbulent shear flow is investigated using direct numerical simulations (DNS) of the incompressible Navier–Stokes equations on a 5123 grid, and with viscous rapid distortion theory (RDT). We use a novel pseudo-spectral algorithm that allows us to set the initial value of the shear parameter in the range 3–30 without the shortcomings of previous numerical approaches. We find there is an explicit dependence of the early-time behaviour on the initial value of the shear parameter. Moreover, the long-time asymptotes of la

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Khanal and Weijermars. "Modeling Flow and Pressure Fields in Porous Media with High Conductivity Flow Channels and Smart Placement of Branch Cuts for Variant and Invariant Complex Potentials." Fluids 4, no. 3 (August 9, 2019): 154. http://dx.doi.org/10.3390/fluids4030154.

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A long overdue distinction between so-called variant and invariant complex potentials is proposed here for the first time. Invariant complex potentials describe physical flows where a switch of the real and imaginary parts of the function will still describe the same type of physical flow (but only rotated by π/2). Such invariants can be formulated with Euler’s formula to depict the same flow for any arbitrary orientation with respect to the coordinate system used. In contrast, variant complex potentials, when swapping their real and imaginary parts, will result in two fundamentally different

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