The principal focus of this study was the measurement relative brain motion with respect to skull using a high-speed, biplanar x-ray system and neutral density targets (NDTs). A suspension fixture used for testing inverted, perfused, human cadaver heads. Each specimen subjected multiple tests, either struck at rest 152-mm-diameter padded impactor face, or stopped against an angled surface from steady-state motion. impacts were frontal occipital regions. An array NDTs implanted in...

High-speed biplane x-ray and neutral density targets were used to examine brain displacement deformation during impact. Relative motion, maximum principal strain, shear intracranial pressure measured in thirty-five impacts using eight human cadaver head neck specimens. The effect of a helmet was evaluated. During impact, local tissue tends keep its position shape with respect the inertial frame, resulting relative motion between skull brain. motions tend follow looping patterns. Similar...

Graphene has served as the model 2D system for over a decade, and effects of grain boundaries (GBs) on its electrical mechanical properties are very well investigated. However, no direct measurement correlation between thermal transport graphene GBs been reported. Here, we report simultaneous comparison in supported single crystalline to across an individual GB. Our experiments show that conductance (per unit area) through isolated GB can be up order magnitude lower than theoretically...

We have cloned and expressed a Ca(2+)-activated K+ channel beta-subunit from human brain. The open reading frame encodes 191-amino acid protein possessing significant homology to previously described subunit bovine muscle. gene for this is located on chromosome 5 at band q34 (hslo-beta). There no evidence alternative RNA splicing of product. hslo-beta mRNA abundantly in smooth muscle, but expression levels are low most other tissues, including Brain subregions which relatively high the...

In many device architectures based on 2D materials, a major part of the heat generated in hot‐spots dissipates through‐plane direction where interfacial thermal resistances can significantly restrain removal capability device. Despite its importance, there is an enormous (1–2 orders magnitude) disagreement literature transport characteristics MoS 2 and other transition metal dichalcogenides (TMDs) (0.1–14 MW m −2 K −1 ). this report, boundary conductance (TBC) across graphene monolayers with...

Abstract The strong discontinuity approach to modelling strain localization, combined with an enhanced element, has been used for more than a decade model localization in materials including geomaterials. Most implementations of elements the post‐localization regime use very simple constitutive formulations along discontinuity, such as linear softening or constant friction coefficient. However, relations can be much complex For rocks this is induced by micro‐fractures coalescing into...

Abstract One hypothesized mechanism that triggers deep‐focus earthquakes in oceanic subducting slabs below ∼300 km depth is transformational faulting due to the olivine‐to‐spinel phase transition. This study uses finite element modeling investigate transformation‐induced stress redistribution and material weakening olivine. A thermodynamically consistent constitutive model developed capture evolution of transformation olivine under different pressure temperature conditions. The overall...

This study characterizes the response of human cadaver abdomen to high-speed seatbelt loading using pyrotechnic pretensioners. A test apparatus was developed deliver symmetric a equipped with two low-mass load cells. Eight subjects were tested under worst-case scenario, out-of-position (OOP) conditions. placed at level mid-umbilicus and drawn back along sides specimens, which seated upright fixed-back configuration. Penetration measured by laser, tracked anterior aspect abdomen, video....

Summary The Sandia GeoModel is a continuum elastoplastic constitutive model that captures many features of the mechanical response for geological materials over wide range porosities and strain rates. Among specific incorporated into formulation are smooth compression cap, isotropic/kinematic hardening, nonlinear pressure dependence, strength differential effect, rate sensitivity. This study attempts to provide enhancements regarding computational tractability, domain applicability,...

Through-plane thermal transport accounts for a major fraction of heat dissipation from hot-spots in many existing devices made two-dimensional (2D) materials. In this report, we performed set electrical thermometry measurements and 3D finite element analyses to quantify the limits power monolayer graphene, representative 2D materials, fabricated on various technologically viable substrates such as chemical vapor deposited (CVD) diamond, tape-casted (sintered) aluminum nitride (AlN), single...

The mechanical behavior of soils may be approximated using different models that depend on particular soil characteristics and simplifying assumptions. For this reason, researchers have proposed expounded upon a large number constitutive approaches describe various aspects behavior. However, there are few material capable predicting the for engineering applications at same time appropriate implementation into finite element (FE) multibody system (MBS) algorithms. This paper presents survey...

Summary This paper presents a u‐p (displacement‐pressure) semi‐Lagrangian reproducing kernel (RK) formulation to effectively analyze landslide processes. The RK approximation is constructed based on Lagrangian discretization points with fixed supports in the current configuration. As result, it tracks state variables at while allowing extreme deformation and material separation that beyond capability of formulations. following Biot theory incorporated into describe poromechanics saturated...

We describe a framework for mathematical modeling of slip weakening in an initially intact rock mass due to shear strain localization along any arbitrary plane. The technique considered is based on continuum mechanics and may be cast directly into standard nonlinear finite element algorithm the analysis prefailure postfailure responses geological systems boundary value problem. behavior represented by constitutive model; characterized frictional yielding surface with state‐...

Cement stabilized soil block (CSSB) is a modern earthen building material that used in the construction of masonry structures. Most studies involving CSSB have focused on how its composition affects strength characteristics and properties such as erosion. In contrast, very little currently known about structural behavior. This study set forth to address absence data this research area, focusing flexural panel testing, including separate horizontal vertical bending tests. It was found follows...

Abstract Localized deformations such as shear bands, compaction dilation combined shear/compaction or shear/dilation fractures, and joint slippage are commonly found in geomaterials like soil rock. Thus, modeling their inception, development, propagation, effect on mechanical response of the body structure is important. The paper will focus one, now classical, analysis method for inception these localized a rate‐sensitive, non‐associative, three‐invariant, isotropic/kinematic hardening cap...

Most studies involving cement-stabilized soil blocks (CSSB) concern material properties, such as the characteristics of erosion and strength how composition block affects these properties. Moreover, research has been conducted on performance various mortars, investigating their properties tensile bond between CSSB units mortar. In contrast, very little is currently known about masonry structural behavior. Because design codes traditional buildings were well developed over past century, many...

During the maturation of some mammals such as mice and rats, corneal epithelial cells tend to develop into patterns spirals over time. A better understanding these can help understand how organ develops may give insight diseases affecting development. In this paper, a framework for explaining development forming spiral due effect tensile shear strains is proposed. Using chimeric animals, made by combining embryonic from genetically distinguishable strains, we observe in cornea. Aggregates...

Abstract The principal focus of this study is the measurement relative brain motion with respect to skull and between different regions brain. Using a high-speed bi-planer x-ray system reduced density targets (RDT’s), strain in relatively small volume can be determined. Relative determined using implanted triaxial neutral accelerometers (NDA-3’s) rigid-body accelerometer array (3-2-2-2) mounted apex skull. A suspension fixture used for inverted, isolated-head testing. Two occipital impacts,...