Development of a Low-Cost Mechanical Model of a Human Head

2018 ◽  
Author(s):  
Grace Foltz ◽  
Elizabeth Tillotson ◽  
Beth A. Todd
Keyword(s):  
Mechanical Model ◽  
Dynamic Properties ◽  
Chronic Traumatic Encephalopathy ◽  
Low Cost ◽  
Human Head ◽  
Size And Shape ◽  
Crash Testing ◽  
Adult Head ◽  
Head Form ◽  
Testing Linear

In recent years, interest has developed in Chronic Traumatic Encephalopathy (CTE) and the related concussions that occur in sports at both professional and amateur levels. Subsequently there is interest in developing new types of athletic helmets to both absorb energy to detect and reduce concussions. To test these helmets, an appropriate head form must be used that will fit the helmet and also exhibit the dynamic properties of the human head. While much effort has gone into creating biofidelic heads containing instrumentation for automotive crash testing, these heads can cost upwards of $10,000. The goal of this project is to create a head form for a few hundred dollars with the appropriate dynamic properties for testing linear and angular accelerations of a helmet. The specific goals of this project are to create a head form with the following characteristics: 1) External size and shape that will properly fit a hockey helmet; 2) Weight representative of an adult head; 3) Robust enough to withstand a thousand impact tests. The manufacture of the head form and the verification that the design goals are described.

scholarly journals Fracture System and Rock-Mass Characterization by Borehole Camera Surveying: Application in Dimension Stone Investigations in Geologically Complex Structures

2021 ◽  
Vol 11 (2) ◽  
pp. 764
Author(s):  
Ivica Pavičić ◽  
Ivo Galić ◽  
Mišo Kucelj ◽  
Ivan Dragičević
Keyword(s):  
Rock Mass ◽  
Fractured Rock ◽  
Low Cost ◽  
Fracture Pattern ◽  
Dimension Stone ◽  
Rock Mass Characterization ◽  
Size And Shape ◽  
Distribution Parameters ◽  
Borehole Camera ◽  
Fracture Distribution

The successful exploration of dimension stone mainly depends on the quality, size, and shape of extractable blocks of dimension stone. The investigated area is in the Pelješac Peninsula (Croatia), in the External Dinarides orogeny, built from thick carbonate succession, characterized by relatively small deposits of high-quality dimension stone. These conditions demand challenging geological investigations in the “pre-quarry” phase to find optimal quarry location. The size and shape of dimension stone blocks are mainly controlled by fracture pattern systems. In the rugged, covered terrains, it is very hard to obtain a satisfactory amount of fracture data from the surface, so it is necessary to collect them from the underground. Borehole camera technology can visualize the inner part of the rock mass and measure the fracture characteristics. The main conclusions are as follows: (1) the digital borehole camera technology provides a quick, effective, and low-cost geological survey of fractured rock mass; (2) statistical fracture distribution parameters, P10, fracture spacing, Volumetric Joint Count (Jv) based on borehole wall survey can reflect the integrity of rock mass, providing a solid decision-making base for further investment plans and dimension stone excavation method.

Modal Analyses of Deployable Truss Structures Based on Shape Memory Polymer Composites

2016 ◽  
Vol 08 (07) ◽  
pp. 1640009 ◽  
Author(s):  
Fengfeng Li ◽  
Liwu Liu ◽  
Xin Lan ◽  
Tong Wang ◽  
Xiangyu Li ◽  
...  
Keyword(s):  
Finite Element ◽  
Shape Memory ◽  
Polymer Composites ◽  
Dynamic Properties ◽  
Low Cost ◽  
Shape Memory Polymer ◽  
Truss Structures ◽  
Modal Test ◽  
The Stability ◽  
Mechanical Devices

With large spatial deployable antennas used more widely, the stability of deployable antennas is attracting more attention. The form of the support structure is an important factor of the antenna’s natural frequency, which is essential to study to prevent the resonance. The deployable truss structures based on shape memory polymer composites (SMPCs) have made themselves feasible for their unique properties such as highly reliable, low-cost, light weight, and self-deployment without complex mechanical devices compared with conventional deployable masts. This study offers deliverables as follows: an establishment of three-longeron beam and three-longeron truss finite element models by using ABAQUS; calculation of natural frequencies and vibration modes; parameter studies for influence on their dynamic properties; manufacture of a three-longeron truss based on SMPC, and modal test of the three-longeron truss. The results show that modal test and finite element simulation fit well.

THE SIZE AND SHAPE OF HUMAN HEAD HAIR

1942 ◽  
Vol 33 (8) ◽  
pp. 302-304 ◽  
Author(s):  
HENRI C. SEIBERT ◽  
MORRIS STEGGERDA
Keyword(s):  
Human Head ◽  
Size And Shape ◽  
Head Hair

Monte Carlo simulation of light propagation in adult brain: influence of tissue blood content and indocyanine green

2008 ◽  
Vol 16 (2) ◽  
Author(s):  
P. Niederer ◽  
R. Mudra ◽  
E. Keller
Keyword(s):  
Monte Carlo ◽  
Indocyanine Green ◽  
Light Propagation ◽  
Near Infrared ◽  
Human Head ◽  
Adult Brain ◽  
Blood Content ◽  
Representative Model ◽  
Adult Head ◽  
Clinically Significant

AbstractNear-infrared spectroscopy (NIRS), applied to a human head, is a noninvasive method in neurointensive care to monitor cerebral hemodynamics and oxygenation. The method is particularly powerful when it is applied in combination with indocyanine green (ICG) as a tracer substance. In order to assess contributions to the measured optical density (OD) which are due to extracerebral circulation and disturb the clinically significant intracerebral signals, we simulated the light propagation in an anatomically representative model of the adult head derived from MRI measurements with the aid of Monte Carlo methods. Since the measured OD signal depends largely on the relative blood content in various transilluminated tissues, we weighted the calculated densities of the photon distribution under baseline conditions within the tissues with the changes and aberrations of the relative blood volumes which we expect to prevail under physiological conditions. Furthermore, the influence of the IGC dye as a tracer substance was assessed. We conclude that up to about different 70% of the measured OD signal may have its origin in the tissues of interest under optimal conditions, which is mainly due to the extrapolated high relative blood content of brain tissue along with the influence of ICG.

Technical Notes. Earmuff Noise Leakage Measurements and Evaluation

2015 ◽  
Vol 40 (1) ◽  
pp. 109-115 ◽  
Author(s):  
Samir N.Y. Gerges ◽  
Rafael N.C. Gerges ◽  
Roberto A. Dias
Keyword(s):  
Contact Area ◽  
Flat Surface ◽  
Low Cost ◽  
Human Head ◽  
Noise Attenuation ◽  
High Quality ◽  
Quantitative Effect ◽  
Hearing Protectors

Abstract This paper reports the quantitative effect of leakage on the noise attenuation of earmuff hearing protectors. The technology used in this study to measure the noise leakage is considered to be a new contribution to this topic. An array of sensors placed between an earmuff and a dummy human head or flat surface was used to measure the contact area. Areas of no contact are considered as the leakage elements. Eight earmuffs varying from high quality/high cost to low quality/low cost were tested, the leakage areas were measured and the reduction in the noise attenuation due to leakage was calculated

Dynamic properties of the human head

1976 ◽  
Vol 48 (1) ◽  
pp. 35-43 ◽  
Author(s):  
J.B. Smith ◽  
C.W. Suggs
Keyword(s):  
Dynamic Properties ◽  
Human Head

Size and shape controlled hydrothermal synthesis of kesterite Cu2ZnSnS4 nanocrystals

RSC Advances ◽  
2014 ◽  
Vol 4 (61) ◽  
pp. 32530-32533 ◽  
Author(s):  
Seung Wook Shin ◽  
Woo Ri Bae ◽  
Han Seung Yang ◽  
Chang Woo Hong ◽  
Hyo Rim Jung ◽  
...  
Keyword(s):  
Hydrothermal Synthesis ◽  
Low Cost ◽  
Toxic Chemicals ◽  
Hydrothermal Technique ◽  
Size And Shape ◽  
Shape Controlled ◽  
Czts Nanocrystals

Quaternary kesterite Cu2ZnSnS4 (CZTS) nanocrystals (NCs) have been synthesized using a simple, size and shape tunable, and low-cost hydrothermal technique without using toxic chemicals.

scholarly journals Effect of Jute Fibre Orientation and Percentage on Strength of Jute Fibre Reinforced Concrete

2020 ◽  
Vol 9 (3) ◽  
pp. 1767-1770
Keyword(s):  
Tensile Strength ◽  
Reinforced Concrete ◽  
Dynamic Properties ◽  
Low Cost ◽  
Plain Concrete ◽  
Natural Fibre ◽  
Fibre Reinforced Concrete ◽  
Jute Fibre ◽  
Micro Cracks ◽  
Crack Arrester

The demerits of plain concrete are its lesser tensile strength, not significant ductility and poor resistance to cracking. Due to propagation of internal micro cracks in plain concrete causes decrease in tensile strength, hence leads concrete to brittle fracture. Addition of fibres behaves like crack arrester and enhances the dynamic properties of concrete. In India natural fibres such as bamboo, coir, jute, sisal, pineapple, banana, ramie etc are high available. Jute is a useful natural fibre for concrete reinforcement due to its easy availability and low cost. In this research, the experiments related to Jute fibre reinforced concrete (JFRC) are done by taking different fibre percentage and the compressive strength and modulus of rapture value observed. This JFRC can replace plain concrete and wood in many cases for example in door and window panels, inclined roof slabs, partition walls etc

scholarly journals SELF-SIMILAR STRUCTURES IN BIOMECHANICS. HUMAN VIBRORECEPTORS

2021 ◽  
Vol 161 ◽  
pp. 10-19
Author(s):  
L.Ya. Banakh
Keyword(s):  
Periodic Structure ◽  
Mechanical Model ◽  
Dynamic Properties ◽  
Incoming Signal ◽  
Inertial Parameters ◽  
Self Similar ◽  
Pacini Corpuscle

The concept of dynamic-fractal self-similar structures (dynamic fractal) is introduced. This concept consists in scaling the dynamic, i.e. elastic-inertial parameters of the forming cells. It is shown that a dynamic fractal decreasing in length amplifies the incoming signal along the structure. A dynamic fractal that increases in length, on the contrary, has the good vibroisolation properties, the attenuation intensity in which is higher than in the periodic structure. The dynamic properties of the Pacini corpuscle, which is a human vibration detector, are investigated. Its mechanical model is constructed. It is shown that the vibroreceptor is a dynamic fractal with parameters decreasing in length. Therefore the vibroreceptor amplifies the incoming signal, which makes it possible to detect even weak vibration effects on a person

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