scholarly journals A First-Order Mechanical Device to Model Traumatized Craniovascular Biodynamics

2006 ◽  
Vol 1 (1) ◽  
pp. 89-95
Author(s):  
Sean S. Kohles ◽  
Ryan W. Mangan ◽  
Edward Stan ◽  
James McNames
Keyword(s):  
Mathematical Models ◽  
Physical Model ◽  
Brain Tissue ◽  
Head Injuries ◽  
Post Injury ◽  
Traumatic Head Injury ◽  
First Order ◽  
Mechanical Models ◽  
Bed Position ◽  
Poiseuille’S Equation

Mathematical models currently exist that explore the physiology of normal and traumatized intracranial function. Mechanical models are used to assess harsh environments that may potentially cause head injuries. However, few mechanical models are designed to study the adaptive physiologic response to traumatic brain injury. We describe a first-order physical model designed and fabricated to elucidate the complex biomechanical factors associated with dynamic intracranial physiology. The uni-directional flow device can be used to study interactions between the cranium, brain tissue, cerebrospinal fluid, vasculature, blood, and the heart. Solid and fluid materials were selected to simulate key properties of the cranial system. Total constituent volumes (solid and fluid) and volumetric flow (650ml∕min) represent adult human physiology, and the lengths of the individual segments along the flow-path are in accord with Poiseuille’s equation. The physical model includes a mechanism to simulate autoregulatory vessel dynamics. Intracranial pressures were measured at multiple locations throughout the model during simulations with and without post-injury brain tissue swelling. Two scenarios were modeled for both cases: Applications of vasodilation/constriction and changes in the head of bed position. Statistical results indicate that all independent variables had significant influence over fluid pressures measured throughout the model (p<0.0001) including the vasoconstriction mechanism (p=0.0255). The physical model represents a first-order design realization that helps to establish a link between mathematical and mechanical models. Future designs will provide further insight into traumatic head injury and provide a framework for unifying the knowledge gained from mathematical models, injury mechanics, clinical observations, and the response to therapies.

scholarly journals Famous head injuries of the first aerial war: deaths of the “Knights of the Air”

2015 ◽  
Vol 39 (1) ◽  
pp. E5
Author(s):  
Prateeka Koul ◽  
Christine Mau ◽  
Victor M. Sabourin ◽  
Chirag D. Gandhi ◽  
Charles J. Prestigiacomo
Keyword(s):  
Head Injury ◽  
World War I ◽  
Head Injuries ◽  
World War ◽  
Traumatic Head Injury ◽  
The Public ◽  
Time Period ◽  
Traumatic Head ◽  
The Media

World War I advanced the development of aviation from the concept of flight to the use of aircraft on the battlefield. Fighter planes advanced technologically as the war progressed. Fighter pilot aces Francesco Baracca and Manfred von Richthofen (the Red Baron) were two of the most famous pilots of this time period. These courageous fighter aces skillfully maneuvered their SPAD and Albatros planes, respectively, while battling enemies and scoring aerial victories that contributed to the course of the war. The media thrilled the public with their depictions of the heroic feats of fighter pilots such as Baracca and the Red Baron. Despite their aerial prowess, both pilots would eventually be shot down in combat. Although the accounts of their deaths are debated, it is undeniable that both were victims of traumatic head injury.

scholarly journals World Experience in Creating Mathematical Models of Air Springs: Advantages and Disadvantages

2021 ◽  
pp. 25-42
Author(s):  
A. Y Kuzyshyn ◽  
S. A Kostritsia ◽  
Yu. H Sobolevska ◽  
А. V Batih
Keyword(s):  
Mathematical Model ◽  
Finite Element ◽  
Mathematical Models ◽  
Dynamic Behavior ◽  
High Speed ◽  
Vertical Direction ◽  
Rolling Stock ◽  
Air Spring ◽  
Advantages And Disadvantages ◽  
Mechanical Models

Purpose. Taking into account the production and commissioning of modern high-speed rolling stock, the authors are aimed to analyze the currently created mathematical models describing the dynamic behavior of the air spring, systematize them and consider the advantages and disadvantages of each model type. Methodology. For the analysis, a comparative chronological method was used, which makes it possible to trace the development of several points of view, concepts, theories. In accordance with the adopted decision equations, the existing models of air springs were divided into three groups: mechanical, thermodynamic and finite-elements. When analyzing mathematical models, the influence of a number of parameters on the dynamic behavior of the air spring, such as disturbing force frequency, heat transfer, nonlinear characteristics of materials, the shape of the membrane, etc., was considered. Findings. A feature of mechanical models is the determination of input parameters based on the analysis of experimental results, requires access to complex measuring equipment and must be performed for each new model of an air spring separately. Unlike mechanical models, which allow taking into account the damping effect of an air spring in the horizontal and vertical direction, thermodynamic models are mainly focused on studying the dynamic behavior of an air spring in the vertical direction. The use of the finite element method makes it possible to most accurately reproduce the dynamic behavior of an air spring, however, it requires significant expenditures of time and effort to create a finite element model and perform calculations. Originality. Mathematical models of the dynamic behavior of an air spring are systematized, and the importance of their study in conjunction with a spatial mathematical model of high-speed rolling stock is emphasized. Practical value. The analysis of the mathematical models of the dynamic behavior of the air spring shows the ways of their further improvement, indicates the possibility of their use in the spatial mathematical model of the rolling stock in accordance with the tasks set. It will allow, even at the design stage of high-speed rolling stock, to evaluate its dynamic characteristic and traffic safety indicators when interacting with a railway track.

Delayed Homicides Due to Infant Head Injury Initially Reported as Natural (Cerebral Palsy) Deaths

2008 ◽  
Vol 11 (1) ◽  
pp. 39-45 ◽  
Author(s):  
James R. Gill ◽  
Raffaella A. Morotti ◽  
Vincent Tranchida ◽  
Jacquelyn Morhaime ◽  
Hernando Mena
Keyword(s):  
New York ◽  
Cerebral Palsy ◽  
Head Injury ◽  
Head Injuries ◽  
Border Zone ◽  
Traumatic Head Injury ◽  
Manner Of Death ◽  
Proximate Cause ◽  
Delayed Effects ◽  
Initial Injury

A spectrum of neuropathology occurs in infants who sustain traumatic brain injury. Because of a prolonged survival interval, there is a risk that these deaths may not be recognized as a sequel of trauma. We reviewed the records in New York City of 5 delayed fatalities due to nonaccidental infant head injury that had survival intervals from 2.5 to 17 years. The head injuries occurred at 2 to 3 months of age, and death occurred at 2.5 to 17 years of age. Initially, they were reported as natural deaths by treating physicians, families, and/or police. All 5 infants had unexplained or poorly explained remote traumatic head injury that included subdural hematomas. At autopsy, the neuropathologic exam demonstrated remote subdural hemorrhages and lesions related to chronic hypoxic-ischemic injury including atrophy, arterial infarcts, border-zone infarcts, and cystic encephalomalacia. Each child survived the initial injury but later succumbed to the delayed effects of secondary hypoxic-ischemic encephalopathy. These 5 deaths highlight the need to investigate independently the medical history of any child (or adult) who dies with a clinical diagnosis of “cerebral palsy.” The term cerebral palsy often is used as a catchall for any patient who has had neurologic impairment since infancy or childhood. If there is a direct link between the initial injury and the death, even if the injury occurred many years before death, then the injury is the proximate cause of death and dictates the manner of death. All 5 deaths were certified as homicides.

Closed-head injuries followed by detached brain tissue in the external auditory canals

2020 ◽  
Vol 16 (4) ◽  
pp. 735-739
Author(s):  
Danica Cvetković ◽  
Vladimir Živković ◽  
Slobodan Nikolić
Keyword(s):  
Brain Tissue ◽  
Head Injuries ◽  
Closed Head Injuries ◽  
Closed Head

scholarly journals A Partial Lagrangian Approach to Mathematical Models of Epidemiology

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
R. Naz ◽  
I. Naeem ◽  
F. M. Mahomed
Keyword(s):  
Mathematical Models ◽  
Exact Solutions ◽  
Numerical Solutions ◽  
First Integrals ◽  
Order Equation ◽  
Second Order ◽  
Lagrangian Approach ◽  
Hiv Model ◽  
First Order ◽  
Partial Lagrangian

This paper analyzes the first integrals and exact solutions of mathematical models of epidemiology via the partial Lagrangian approach by replacing the three first-order nonlinear ordinary differential equations by an equivalent system containing one second-order equation and a first-order equation. The partial Lagrangian approach is then utilized for the second-order ODE to construct the first integrals of the underlying system. We investigate the SIR and HIV models. We obtain two first integrals for the SIR model with and without demographic growth. For the HIV model without demography, five first integrals are established and two first integrals are deduced for the HIV model with demography. Then we utilize the derived first integrals to construct exact solutions to the models under investigation. The dynamic properties of these models are studied too. Numerical solutions are derived for SIR models by finite difference method and are compared with exact solutions.

Diffuse Axonal Injury and Degradation in Mechanical Characteristics of Brain White Matter

2008 ◽  
Author(s):  
Nabi Abolfathi ◽  
Abhai Naik ◽  
Mahdi Sotudeh ◽  
Ghodrat Karami ◽  
Mariusz Ziejewski
Keyword(s):  
Brain Tissue ◽  
Fibrous Composite ◽  
Axonal Injury ◽  
Diffuse Axonal Injury ◽  
Viscoelastic Behavior ◽  
Severe Disabilities ◽  
Post Injury ◽  
Brain White Matter ◽  
Injured Brain

Diffuse Axonal Injury (DAI) can happen due to sudden motions of head and is one of the major causes of fatality and severe disabilities. To study DAI, any change in material characteristics of brain tissue post injury needs to be well understood. In this study, the focus will be on changes in the viscoelastic material properties of white mater in the brain due to DAI resulting in axonal disconnections. Using a micromechanics fibrous composite modeling for white mater, we have developed an algorithm to analyze the effect of discontinuity due to breakage of axons inside the surrounded matrix. Repeated unit cell (RUC) was assumed to represent the axonal distribution within the extracellular matrix. Relaxation test were conducted for characterization of the viscoelastic behavior. The result of this study provides a modeling technique for characterization of injured brain tissue in white mater and proposes necessity of including the appropriate post injury axonal mechanical properties. These findings can improve the understanding of injury from mechanical perspective and help in predicting vulnerability of any such injured tissue against further injuries.

Thermo-Micromechanical Vibration Behaviors of FGM Structures with Neutral Surface

2017 ◽  
Vol 864 ◽  
pp. 162-166
Author(s):  
Tae Kyung Lim ◽  
Ji Hwan Kim
Keyword(s):  
Thermal Environment ◽  
Shear Deformation Theory ◽  
Elastic Vibration ◽  
Functionally Graded ◽  
Reference Plane ◽  
Neutral Surface ◽  
Temperature Dependent ◽  
Graded Materials ◽  
First Order ◽  
Mechanical Models

This work presents the micro-mechanical models in thermal environment for the vibration behavior of Functionally Graded Materials (FGMs) plate using First-order Shear Deformation Theory (FSDT). In the formulation, the heat transfer effects and the temperature-dependent material properties are considered. Relative estimation of micromechanical behaviors of Mori-Tanaka Method (MTM) is used. And, neutral surface concept is adopted as the reference plane due to the asymmetry in the thickness direction of the model. In the numerical analysis, Finite Element Method is applied for various volume fractions and temperature rising conditions. Also Power-law and Sigmoid FGMs are discussed in thermo-elastic vibration characteristics.

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