Cellular Helmet Liner Design through Bio-inspired Structures and Topology Optimization of Compliant Mechanism Lattices

The continuous development of sport technologies constantly demands advancements in protective headgear to reduce the risk of head injuries. This article introduces new cellular helmet liner designs through two approaches. The first approach is the study of energy-absorbing biological materials. The second approach is the study of lattices comprised of force-diverting compliant mechanisms. On the one hand, bio-inspired liners are generated through the study of biological, hierarchical materials. An emphasis is given on structures in nature that serve similar concussion-reducing functions as a helmet liner. Inspiration is drawn from organic and skeletal structures. On the other hand, compliant mechanism lattice (CML)-based liners use topology optimization to synthesize rubber cellular unit cells with effective positive and negative Poisson's ratios. Three lattices are designed using different cellular unit cell arrangements, namely, all positive, all negative, and alternating effective Poisson's ratios. The proposed cellular (bio-inspired and CML-based) liners are embedded between two polycarbonate shells, thereby, replacing the traditional expanded polypropylene foam liner used in standard sport helmets. The cellular liners are analyzed through a series of 2D extruded ballistic impact simulations to determine the best performing liner topology and its corresponding rubber hardness. The cellular design with the best performance is compared against an expanded polypropylene foam liner in a 3D simulation to appraise its protection capabilities and verify that the 2D extruded design simulations scale to an effective 3D design

Concert recording 2018-04-19b

[Track 1]. Sonatina meridional / Manuel Ponce -- [Track 2]. Etude no. 6 / Hector Villa-Lobos -- [Track 3]. Milonga / Jorge Cardoso -- [Track 4]. Straight no chaser / T. Monk -- [Track 5]. A child is born / T. Monk -- [Track 6]. Autumn leaves / J. Kosma -- [Track 7]. Body and soul / J. Green -- [Track 8]. All the things you are / J. Kern -- [Track 9]. 4 on 6 / Wes Montgomery -- [Track 10]. Bright size life / P. Metheny -- [Track 11]. Dueling banjos / Arthur Smith -- [Track 12]. Elenor Rigby / Lennon and McCartney -- [Track 13]. Alone / Bryce Holcomb -- [Track 14]. All around me / Flyleaf -- Vital transformation / Mahavisunu Orchestra

Concert recording 2018-04-14

[Track 1]. Lonely avenue / Ray Charles -- [Track 2]. Boogie wonderland / Earth Wind and Fire -- [Track 3]. Think / Aretha Franklin -- [Track 4]. Please please please / James Brown -- [Track 5]. Your precious love / Tammi Terrell -- [Track 6]. September / Earth Wind and Fire -- [Track 7]. Baby brown eyes / Alisha Jones -- [Track 8]. Window seat / Erykah Badu -- [Track 9]. Smooth criminal / Michael Jackson -- [Track 10]. Going down / Norma Whitfield -- [Track 11]. Uptown funk / Mark Ronson Bruno Mars Philip Lawrence Jeff Bhasker Devon Gallaspy Nicholas Williams -- [Track 12]. Curley green hair / Jacob Skinner -- [Track 13]. You think of her / Shelby Sprott -- [Track 14]. Coffee song / Jordan Strickland Walter Ferguson -- [Track 15]. Leave a trace / Churches -- [Track 16]. Real one / Alisha Jones -- [Track 17]. Reality / Jordan Strickland -- [Track 18]. Still into you / Paramore -- [Track 19]. Alive / Carlie Spiers

Concert recording 2017-12-05a

[Track 1]. Lou Brouwer medley / Brouwer -- [Track 2]. One summer\u27s day / Daniel Asbun -- [Track 3]. What a friend we have in Jesus / Brad Paisley -- [Track 4]. Unity village / Pat Metheny -- [Track 5] Truth? / Asher Perkins -- [Track 6]. Invention no. 13 / J.S. Bach -- [Track 7]. Black Orpheus / Stan Getz arranged Luiz Bonfa -- [Track 8]. Five Hawaiian minutes / Shiro Mori -- [Track 9]. Birks works / Dizzy Gillespie -- [Track 10]. Perhaps / Charlie Parker -- [Track 11]. The river / King Gizzard and the Lizard Wizard -- [Track 12]. Minor swing / Django Reinhardt and Stephan Grappelli -- [Track 13]. Why break mine / Legally blind -- [Track 14]. Monochrome / Carlie Spiers -- [Track 15]. Stuck in voodoo / Dawson Scantling -- [Track 16]. I\u27m saved / Shelby Sprott -- [Track 17]. Newborn / Muse -- [Track 18]. Blueberry brain / Elephantom

Magnetic resonance microscopy-based analyses of the brains of normal and ethanol-exposed fetal mice

The application of magnetic resonance microscopy (MRM) to the study of normal and abnormal prenatal mouse development has facilitated discovery of dysmorphology following prenatal ethanol insult. The current analyses extend this work, providing a regional brain volume-based description of normal brain growth and illustrating the consequences of gestational day (GD) 10 ethanol exposure in the fetal mouse

Magnetic Resonance Microscopy Defines Ethanol-Induced Brain Abnormalities in Prenatal Mice: Effects of Acute Insult on Gestational Day 7

This magnetic resonance microscopy (MRM)-based report is the 2nd in a series designed to illustrate the spectrum of craniofacial and central nervous system (CNS) dysmorphia resulting from single- and multiple-day maternal ethanol treatment. The study described in this report examined the consequences of ethanol exposure on gestational day (GD) 7 in mice, a time in development when gastrulation and neural plate development begins; corresponding to the mid- to late 3rd week post-fertilization in humans. Acute GD 7 ethanol exposure in mice has previously been shown to result in CNS defects consistent with holoprosencephaly (HPE) and craniofacial anomalies typical of those in Fetal Alcohol Syndrome (FAS). MRM has facilitated further definition of the range of GD 7 ethanol-induced defects

Stage-specific ethanol exposure causes correlative face and brain abnormalities.

<p>Regression lines were plotted for the control group (solid line) and for the ethanol exposure groups (dashed line). In the exposed groups, a significant negative correlation between philtrum length and septal region volume, along with a significant positive correlation between snout width and olfactory bulb volume, was found. Correlations in the control group were not significant (p = 0.55, p = 0.30, respectively).</p