bluuebunny/crossref_metadata_2025_split huggingface dataset:
Flow in a Model of a Ventricular Assist Device: Numerical and Experimental Results
Authors: König C. S. , Clark C. , Mokhtarzadeh-Dehghan M. R. 
Published: January 2022

Abstract
The flow in a ventricular assist device (VAD) is unsteady and three-dimensional, and is characterised by a moving boundary. An experimental model of a VAD was designed specifically to allow validation of numerical results. Qualitative comparisons between the experimental and numerical results were conducted based on the flow patterns of particle paths, obtained from flow visualisation, and of velocity vectors from the simulation. Quantitative comparisons have been conducted based on velocity data using a laser Doppler anemometer (LDA). Validation is being extended in the areas of pressure and wall shear stress distributions, and particle residence times.
An Experimental Model of Interfacial Mechanics in Pulmonary Gas Embolism
Authors: Eckmann David M. , Cavanagh Daniel P. 
Published: January 2022

Abstract
A model of pulmonary gas embolism consists of air bubbles in steady water flow in an inclined rigid acrylic or glass tube. Pressure-flow relationships are measured as a function of tube inclination angle and bubble volume. Flow resistance increases with steeper tube angles and increasing bubble volume. Critical flow rates for bubble detachment and displacement in the upstream and downstream directions are determined. Critical flow rates depend on bubble size, tube material and inclination angle.
A Computational Study of the Flow in Bifurcating Channels and Tubes: Exhalation
Authors: Hassan Amgad A. , Evrensel Cahit A. 
Published: January 2022

Abstract
Researchers have used both the rectangular geometry (Evrensel, et al., 1996, King et al., 1985) and the circular geometry (Kim et al., 1986) to study the effect of the shear stress on the mucus clearance in pulmonary airways. Since the circular geometry makes it practically impossible to keep the mucus layer constant, rectangular geometry is preferable. The main goal of this study is to investigate the differences and similarities between the turbulent flows through bifurcating 2-D rectangular channel and a 3-D circular tube. The geometry studied is similar to the one used in our previous work (Hassan and Evrensel, 1996), but the flow direction is reversed to study the exhalation case. The results indicate a flow separation in downstream of the main branch in both cases and a region of a relatively strong secondary flow for the bifurcating tube. Also, the distribution of the shear stress is shown to be similar in both geometries, although the magnitude of the maximum shear is larger for the circular case.
Effects of Boundary Conditions for the CFD Modelling of Respiratory Flow in an Asymmetric Bifurcation
Authors: Kurujareon Jutarat , Holdø Arne Erik , Calay Rajnish K. 
Published: January 2022

Abstract
Modelling airflow in the conducting airways of the human lungs is important to predict particle deposition of both contaminants and pharmaceuticals. In order to achieve good predictions of deposition the airflow has to be modelled correctly.
Because of the complexity of the bronchial tree structure, the using of the small airways and highly asymmetric of the structure, in vivo studies are difficult for obtaining the global airways effects and the detail of small airways downstream. While the experimental studies are crucial to obtain a somewhat satisfied detail by utilising physiologically scaled up model to study airflow in the lungs. However, those experimental studies are limited up to the 3rd generations of bifurcation and the smaller airways deep within the lungs are inaccessible to most experimental technique even in the scaled up model. CFD studies through the solutions of Navier-Stoke equations seem to be a better way to access the smaller airways and easy to show a large number of data in three dimensional physiologically realistic airway geometries.
In both experimental and CFD simulations the control and choice of boundary conditions are essential. A particular problem is the control of boundary conditions, since the complete lung models cannot be modelled and the experiment in vivo data are not available. The only data available is the flow rate at the mouth as a function of time. Because of the complexity of the airway geometries and the limitation of the present day computer power a truncated lung model has to be used to study in airflow dynamics in the lungs at the first stage. This results in a need to control the flow rates in each airway which causes a problem in the numerical boundary condition.
Thus in the current investigation aims to carry out the appropriate numerical boundary condition for controlling the flow rates in each airway. A two dimensional CFD model of an asymmetric single bifurcation has been used as a test case. This numerical airway model is an anatomic approximation based on Horsfield’s data [Horsfield et al., 1971]. The radii of curvature in the transition zone from the parent branch to daughter branches and a curved shape of carinal ridge have been taken into account on this model. Different flow boundary conditions have been used for respiratory flow. The most realistic result has been obtained by using numerical pistons attached into the end of most downstream airways. Each piston has been enlarged/contracted to generate the required oscillatory flow rate of air through the single bifurcation of the system. The two dimensional CFD model of the airways with numerical pistons along with finite-element mesh model has been shown in figure 1. These results are compared with the published CFD results using standard boundary conditions [Wilquem & Degrez, 1997].
Nonlinear Oscillations in a Collapsible-Tube Model
Authors: Mawasha P. Ruby , Gross Richard , Conway Ted 
Published: January 2022

Abstract
In the present study, a nonlinear analysis is performed for a collapsible tube system consisting of a reservoir with inlet and outlet flow conditions. The forced downstream pressure is modeled as a cubic function similar to the van der Pol equation for a relaxation oscillator. Features that give rise to sustained relaxation oscillations exhibited in the van der Pol oscillator manifest here as inertia due to fluid flow, capacitance due to compressible volume inside the reservoir, and an energy source from the work done by the downstream pressure. Mechanisms that give rise to relaxation oscillations in a collapsible tube system are examined based on numerical results. Also, the effects of compressible volume, length of the channel on pressure and mass flow rate oscillation are investigated.
Thromboresistance of Electrostatically Seeded Endothelial Cells on 4 mm I.D. e-PTFE Using a Canine Femoral Arterial Model
Authors: Bowlin Gary L. , Rittgers Stanley E. , Bulgrin Jeffrey , Sims Rick 
Published: January 2022

Abstract
Recently, an electrostatic technique has been described which enhances EC adhesion and retention upon physiologic shear stress [1–2]. The results of the in vitro evaluation indicated that the optimum electrostatic seeding using human umbilical vein endothelial cells (HUVEC) was obtained at +1.0 Volt applied for a 16 minute seeding time. The optimum conditions resulted in an average EC seeding density of 73,540 HUVEC/cm2 with an average viable surface coverage of 97.4%. The average morphological maturation ranking represented all flattened HUVECs with an average damage ranking corresponding to minimal cellular membrane damage. The HUVEC retention study (in vitro) showed that the optimally electrostatic seeded grafts experienced no significant (α = 0.05) loss of HUVECs upon physiologic shear stress exposure (15 dynes/cm2). The biochemical assay results showed no significant (α = 0.05) production of prostacyclin or thromboxane A2 by either the gravitationally or electrostatically seeded HUVECs [2].
Tools and Techniques for Visualizing Three-Dimensional Medical Datasets
Authors: Tombropoulos Rhea Z. , Huffman John 
Published: January 2022

Abstract
Imaging techniques such as computed tomography (CT) and magnetic resonance (MR) enable physicians to view a patient’s internal anatomy and the relative location of structures within the anatomy. Although, to date, these techniques have been used primarily for diagnosis, three-dimensional medical imaging is beginning to emerge as a powerful tool for training physicians, aiding in presurgical planning, providing intraoperative surgical guidance, and enabling the performance of surgeries remotely. Such new applications demand real-time visualization of medical data in three dimensions, as well as effective methods for interacting with these data.
Use of Daily Activity Data to Assess Injury Potential in Low-Speed Motor Vehicle Crashes
Authors: Paver Jacqueline G. , Khadilkar Anil V. , Ward Carley C. 
Published: January 2022

Abstract
Human tolerance testing has established criteria for the risk of serious-to-fatal injury to specific body regions. Using these criteria, injury potential in motor vehicle crashes has been assessed in sled and full-scale car-crash tests using volunteers, anthropomorphic dummies, and cadavers. Based on these criteria, vehicle compliance testing is aimed to protect occupants from serious-to-fatal injury. However, there exists no threshold or minimum crash severity (e.g., delta V) that establishes a “no injury” v. “injury” condition. This study addresses efforts to establish such a condition and identifies confounding factors, the most confused of which may be injury pattern, severity, and symptom duration. Volunteer data was compiled from measurements made during non-injurious daily activities and compared to loading experienced by similarly-instrumented volunteers in low-speed sideswipe, angled-side, broadside, rear-end, and front-end impacts. These results support the use of daily activity data for comparisons of loading and provide additional data to establish non-injurious crash severities in low-speed motor vehicle accidents. However, for different types of impacts, additional work is still required to establish accepted thresholds above which “injury” is probable.
Biomechanical Analysis of Restraint Receptacles
Authors: Sances Anthony 
Published: January 2022

Abstract
Various designs of automotive restraint receptacles (buckles) are currently in use which can release inertially. A substantial number of patents exist for designs of receptacles that protect against inertial unlatching. Furthermore, a number of currently manufactured receptacles are of anti-inertial unlatching design. This study was conducted to evaluate various receptacles which are susceptible to inertial unlatching to determine the impact speed, the applied force and acceleration with a laboratory pendulum using various interface materials. The receptacles without anti-inertial design opened at speeds of 2.2 to 3.4 meters/second with forces in the region of 220N to 440N at accelerations to 100 G’s at the time of unlatching. In contrast, the anti-inertial designed receptacles did not open at speeds up to 5.4 meters/second with corresponding higher impact force and acceleration.
Directional Properties of Gray and White Brain Tissue Undergoing Large Deformation
Authors: Prange Michael T. , Meaney David F. , Margulies Susan S. 
Published: January 2022

Abstract
Biomechanical analyses of diffuse axonal injury (DAI) suggest a link between brain material response (stress or strain) and white matter injury (Margulies et al., 1990; Meaney et al., 1994; Mendis et al., 1995; Lee et al., 1987; Zhou et al., 1994). Material properties of the brain tissue, including a description of their inhomogeneity, are important to predict intracranial deformations from the applied inertial loads. It is essential that these properties are defined separately for the gray and white matter, and account for the potential nonlinear viscoelasticity at finite strains.
Microstructural Kinematics During Elongation of Central Nervous System Tissue: Implications for Traumatic Axonal Injury
Authors: Bain Allison C. , Meaney David F. 
Published: January 2022

Abstract
Diffuse axonal injury (DAI) is the most common form of closed head injury and is responsible for over a third of all head injury deaths. Axons are the primary constituent of the white matter in the brain, and frequently form aligned tracts in the brain. Research has indicated that traumatic axonal injury occurs when these axons experience tensile strains above a critical level. Our laboratory is currently working toward identifying injurious strain levels for axons using the optic nerve stretch model. The optic nerve is an isolated bundle of aligned central nervous system (CNS) axons, thus, dynamic elongation of the optic nerve is an in vivo approximation of the process by which axons are injured in the brain.
Parametric Tests of the Human Pelvis: The Influence of Load Rate and Boundary Condition on Peak Stress Location During Simulated Side Impact
Authors: Plummer Jason W. , Eberhardt Alan W. , Alonso Jorge , Mann Kenneth A. 
Published: January 2022

Abstract
Pelvic fractures occur in 8% to 14% of near-side automobile collisions (Cesari et al., 1980). The type of fracture varies widely and includes pubic rami, pubic symphysis, acetabuli, sacro-iliac joint, and iliac wing fractures. In the laboratory environment, fractures of the pubic rami have been reproduced in both full cadaver (Cavanaugh et al., 1990) and isolated pelvis studies (Guillemot et al., 1997). Recently, Molz and co-workers (1997) found acetabular fractures in their isolated pelvic experiments. However, the loading history and mechanical boundary conditions for the two experiments varied widely.
Intervertebral Disc Pressure Changes During Low Back Treatment Procedures
Authors: Gudavalli Maruti R. , Cox James M. , Cramer Gregory D. , Baker James A. , Patwardhan Avinash G. 
Published: January 2022

Abstract
Some of the treatments for low back pain use different motions to the spine. One such treatment protocol used by chiropractic physicians in the treatment of low back pain is the Cox flexion-distraction procedure (1). The Cox procedure consists of placing the patient in a prone position on a flexion-distraction table and then creating distraction, flexion, extension, lateral flexion, and circumduction motions at the joint of interest. Gudavalli et al. (2) reported decreases in intradiscal pressures during the combined motions of flexion-distraction motions. However, no data exist during other motions of the table. The purpose of the present study was to measure the changes in the intradiscal pressures during all the maneuvers of the treatment protocols.
A Multi-Body Optical Measurement System for the Study of Human Joint Motion
Authors: DiAngelo Denis J. , Vossel Keith A. , Jansen Thomas H. 
Published: January 2022

Abstract
Human joint systems exhibit complex, coupled movement patterns. Various measurement devices have been developed to study human joint behavior. They include electromechanical, electromagnetic, and electro-optical systems; and radiographic techniques [Lim et al., 1997; Milne et al., 1996; Moeini et al., 1996]. When measuring global joint motion, accuracy of the system must be considered. Measures of “relative” joint motion depend on system resolution and repeatability. An improved three-dimensional (3-D) non-contact measurement system was develop to study human joint motion. System calibration for two-dimensional (2-D) analysis was performed. Application to the cervical spine is presented.
Biomechanical Study on C4-C7 Cervical Spine
Authors: Natarajan R. N. , Chen B. H. , An H. S. , Andersson G. B. J. 
Published: January 2022

Abstract
It is known that surgery performed at one level in the spine affects the biomechanical characteristics of adjacent levels. Study of biomechanical response such as change in flexibility at the level of surgery as well as change in motions at the adjacent levels to applied multiplaner loadings will help to understand effects of surgery and rehabilitation requirements in these tissues. Experimental studies on the effect of large number of different surgeries on the stability of cervical spine are very expensive and time consuming if not impossible. Finite element modeling can be effectively used under these circumstances. Recent developments in this area have produced 2 segment (C4-C6) finite element models (Yoganandan et al., 1996). Three-motion segment model becomes necessary to understand the unconstrained effect of different surgical procedures performed at the middle level. The present study focuses on the biomechanical characteristics of a three motion segment model (C4-C7) so that it is possible to study the effect of surgery at the C5-C6 level without any interference from either the applied loading or the boundary conditions. The three-motion segment finite element model was validated under pure flexion and torsion moment loadings.
Geriatric Cervical Spine Biomechanics: Effect of Degeneration Severity on Biomechanical Response
Authors: Kumaresan Srirangam , Yoganandan Narayan , Pintar Frank A. , Maiman Dennis J. 
Published: January 2022

Abstract
Biomechanical responses of the geriatric cervical spine with varying degrees of degeneration were studied using an anatomically accurate three-dimensional nonlinear detailed finite model of the human lower cervical spine. The geometrical details of the bony structure of the cervical spine model were obtained from the computed tomography images and the soft tissue details from cryomicrotome anatomic sections. The finite element model was validated under physiologic compression, flexion, extension and eccentric complex loading modes in terms of the angular stiffness, and the localized strain in the vertebral body and bilateral facet masses. Different levels of degenerated conditions in the cervical spine model were simulated by altering the material properties of the intervertebral nucleus pulposus, fiber content in the annulus fibrosus and decrease in the height of the disc. The external stiffness and internal stress responses of geriatric degenerated spines were compared with the adult normal spine. The overall stiffness of the geriatric spine increased with increasing severity of degeneration. Similarly, the stress magnitudes in the vertebral body increased with increasing levels of degeneration.
Stress Distribution in Osteoarthritic and Normal Glenohumeral Joints: A Finite Element Analysis
Authors: Ramaniraka N. , Farron A. , Iannotti J. P. , Rakotomanana L. , Terrier A. , Courvoisier D. , Leyvraz P.-F. 
Published: January 2022

Abstract
Many studies have been conducted to evaluate the pattern of glenoid erosion from CT scans e.g. (Mullaji et al., 1994). The basic postulate was that the knowledge of the eroded geometry compared to the normal ones enabled the choice of the most appropriate design a fixation of glenoid component in presence of osteoarthrisis. The presence of mechanical loadings in soft tissues and bones probably requires the additional knowledge of the stresses within the bones. All these data are then expected to allow the surgery to be planned to obtain the most secure fixation in the available bone. Different complex shoulder models have been introduced in the literature combining the rigid body motion e.g. (Engin and Turner, 1989) — or beam modelling for bones — with the passive and active truss elements for modelling ligaments and muscles e.g. (Van der Helm et al., 1992). Although providing very useful information on forces and kinematics, most of these models are not interested in the bone stresses particularly at the epiphysis and at the articular surfaces.
Cement Fixation of the Acetabular Cup in Total Hip Replacement: Are 10 mm-Depth Anchorage Holes Required?
Authors: Mootanah Rajshree , Ingle Paul , Watkinson Brian V. , Cheah Kevin , Dowell John 
Published: January 2022

Abstract
Long-term studies have shown that failure of the acetabular component in a total hip replacement increases exponentially ten years following surgery (Morscher, 1992). During the cemented fixation of the acetabular cup in a total hip replacement, anchorage holes are drilled in the acetabulum in order to increase the torsional resistance of cement bonding. So far, there seems to be no definite number, size, shape, location and depth of the anchorage holes. Usually, the depth is 10mm, the edge is 90°, while the number and size of holes are interrelated; the smaller the diameter of the hole, the larger the number of holes are drilled and vice versa.
A Mixed Finite Element Formulation of Triphasic Theory and its Application to Free Swelling Problem
Authors: Sun D. N. , Guo X. E. , Lai W. M. , Mow V. C. , Gu W. Y. 
Published: January 2022

Abstract
It has been shown that the triphasic theory [1] is capable of describing many mechano-electrochemical phenomena observed in charged hydrated soft tissues or cells, such as free-swelling, stress-relaxation, streaming potential, diffusion potential, and electro-osmosis [e.g., 1–3]. The theory is useful for the study of signal transduction mechanisms at both tissue and cellular levels. This is important to understanding tissue physiology and pathology. To facilitate applications of the triphasic theory to many practical problems, it is necessary to develop a numerical method for quantitatively investigating tissue behaviors. Thus, the objective of this study is to develop a finite element formulation for the triphasic theory. A free-swelling problem was studied using this finite element method to investigate effects of inhomogeneity of fixed charge density (FCD) on ion concentration, tissue deformation, fluid flow and streaming potential etc.
A Generalized Self-Consistent Method for Osteonal Cortical Bone Modeling
Authors: Guo X. Edward , Dong X. Neil , Huang Y. Young 
Published: January 2022

Abstract
Morphologically, cortical bone resembles a fiber-matrix composite material such that an osteon is analogous to the fiber while the interstitial bone to the matrix. For example, there have been several studies addressing the mechanical properties of cortical bone based on this point of view (Hogan 1992, Aoubiza et al. 1996). Our interest in cortical bone mechanics stems from the characterization and mechanisms of microdamage such as microcracks in cortical bone. The exponential increase of microdamage in cortical bone tissue has been implicated in increased bone fragility with aging (Schaffler et al. 1995). None of these above mentioned techniques can be conveniently used for our long term study on cortical bone damage mechanics. Recently, significant advances have been made in the mechanics of composite materials. For example, a generalized self-consistent formulation for effective mechanical properties of composites have been developed such that it can apply to the case where the volume fraction of fibers is as high as 80–90% (Huang et al. 1994). In addition, microcracks can be easily included for damage mechanics or fracture mechanics analysis. The objective of this paper is to develop a general scheme for a cortical bone composite model based on the generalized self-consistent method for calculation of effective elastic properties.
Minimizing Stress Shielding in Hip Implant by Mechanical Design
Authors: Cunningham Robert A. 
Published: January 2022

Abstract
Today’s technology of hip prosthesis implants, where the implant stem is fixed to the internal surface of the femur by bonding, bone growth or press fit, results in “stress shielding” of that portion of the implanted femur. Subsequent bone atrophy often requires remedial work and/or replacement of the hip prosthesis. A new design is presented in which the manner of the load transfer from the prosthesis to the bone greatly reduces stress shielding. The reduction of the stress shielding is so dramatic that a once-in-a-lifetime installation, without remedial work is a strong possibility.