Digital Commons Network^™

Mechanics Of Elastic Ellipsoidal Shells, Hamid Ebrahimi, Ashkan Vaziri, Amin Ajdari, Dominic Vella, Arezki Boudaoud

Society of Engineering Science 51st Annual Technical Meeting Archive

Complicated structural features at a much smaller scale than overall structure size form during the deformation of elastic shells under mechanical loading. These features which can be seen by simple experiments in everyday life, as well as in biological and engineering systems, are associated with high energy density and evolve in intricate ways as the shell is further loaded deep into the nonlinear regime. The key challenge in understanding these features is interaction of physics and geometry that leads to a mechanical response which is very different from the response of solid objects. The formation of localized periodic structures in …

Mechanical Behavior Of Biomimetic Surface Scales, Ranajay Ghosh

Society of Engineering Science 51st Annual Technical Meeting Archive

Examining the evolutionary response of diverse biological species to counter the existential threats from hostile environmental and predatory landscape can shed light on the principles of protective system design. In this context, dermal scales, prevalent across biological groups imply their versatility in boosting survivability and providing multifunctional advantages for the species. Here, we investigate the nonlinear mechanical effects of biomimetic scale-like attachments on the behavior of an elastic substrate brought about by the contact interaction of scales in pure bending using qualitative experiments, analytical models, and detailed finite element analysis. Our results reveal the existence of three distinct kinematic phases …

An Eulerian Framework For Modeling And Simulating The Nonlinear Dynamics Of Soft Hyperelastic Materials, Robert Lowe

Society of Engineering Science 51st Annual Technical Meeting Archive

In this discussion, we present a novel framework for modeling and simulating the nonlinear elastodynamics of soft hyperelastic materials such as rubbers, elastomers, and biological tissues. The proposed framework differs fundamentally from the standard paradigm in computational mechanics in concept, structure, and methodology. A key feature of our approach is the use of a fixed mesh in tandem with a novel shock-capturing scheme from computational fluid dynamics designed specifically for first-order hyperbolic systems. Our use of a fixed mesh demands an Eulerian formulation of the mathematical model. The mathematical model we employ bridges the Eulerian conservation laws of mass, linear …

Rate-Dependent Toughness In Soft Materials Via Microscopic Scratch Testing, Ange-Therese Akono, Franz-Josef Ulm

Society of Engineering Science 51st Annual Technical Meeting Archive

Although fracture processes are rate-sensitive in a wide variety of biological and engineering systems, such as protein materials and bulk metallic glasses, the exact contribution of the prescribed mechanical loading rate to the measured fracture resistance is not fully understood. In this study, we formulate a novel energy-based framework for crack propagation in nonlinear viscous solids, using microscopic scratch tests. The scratch test consists in pushing a tool across the surface of a weaker material at a given penetration depth, and is relevant to several fields of science and engineering ranging from quality control of thin films and coatings to …

The Maximal Advance Path Constraint For The Homogenization Of Soft Matter Materials, Christian Linder

Society of Engineering Science 51st Annual Technical Meeting Archive

Materials with inherent network microstructures are commonly encountered in materials of artificial and natural origin. Examples are polymer elastomers, hydrogels, soft biological tissues, nonwoven fabrics, or cellular foams. On the microscopic level, those are all composed of elongated one-dimensional elements generally addressed as fibers. When macroscopically deformed, the underlying microstructure undergoes a peculiar deformation resulting in forces produced by the deformed filaments and their interaction within the irregular three-dimensional network. The knowledge about the micromechanics of random networks is therefore of major importance to understand the peculiar mechanical properties displayed by those soft materials. In this presentation, a new mean …

Growth And Instability Of Soft Tissue In Confined Environment, Mir Jalil Razavi Aghjeh, Xianqiao Wang

Society of Engineering Science 51st Annual Technical Meeting Archive

Soft tissues are complex materials with typical nonlinear, anisotropic, inhomogeneous behaviors subjected to large strains and stresses. Growth or atrophy of soft materials (refer both of them as growth in the next) in media may lead to instability and formation of surface wrinkling, folding or creasing which depends on a variety of factors, such as geometry and material properties. Instabilities in the soft materials to adjust the shape configuration and dictate morphological evolution is playing a crucial role in the healthy behavior of soft biological tissues like artery, heart, brain, and airway. Inappropriate growth process may cause physiological and pathological …

A Unified 3d Phase Diagram Of Growth Induced Surface Instabilities, Qiming Wang, Xuanhe Zhao

Society of Engineering Science 51st Annual Technical Meeting Archive

Biological world metabolizes itself with germination, growth, development, and aging every second. A variety of fascinating morphological patterns arise on surfaces of growing, developing or aging tissues, organs and micro--organism colonies. The basic mechanism has been long believed to be the mechanical mismatch due to -differential growth between layers with different biological compositions. These patterns have been observed in separate systems and topologically classified as crease, wrinkle-fold, period-double, ridge, delaminated-buckle, and coexistence states. However, a general and systematic understanding of their initiation and evolution remains largely elusive. We construct a unified 3D phase diagram that predicts initially flat tissue layers …

Determining Local Mechanical Properties Of Biological Scaffolds, Christian Franck

Society of Engineering Science 51st Annual Technical Meeting Archive

The last decade has shown great progress in developing increasingly sophisticated 3D extracellular scaffolds closely mimicking in-vivo environments, yet our understanding of material properties of these scaffolds is still in its infancy. This is in large part due to the lack of available experimental techniques capable of mechanically characterizing these networks at the microscale. Traditional material testing procedures including shear and uniaxial characterization protocols have not been able to resolve details at the microscale due to their intrinsic macroscale nature. Yet, this information is critically important not only to understand how cells function within their surroundings in 3D, but also …

Multiscale Molecular Simulation Of Membranes, Amin Aghaei, Kaushik Dayal

Society of Engineering Science 51st Annual Technical Meeting Archive

Fundamental advances in the understanding of the molecular mechanisms enable a guided strategy towards analysis, modeling, and design of nanoscale structures. An essential difficulty in molecular modeling is that relevant system sizes of interest are very large. Although molecular mechanics has developed accurate models of interactions between individual molecules, the difficulty is that it is simply infeasible to solve these models on existing – or even conceived – computers. Although accurate models of the individual interactions between the molecules are available, the engineered materials typically consist of well over a billion such molecules. However, multiscale methods are well-suited to such …

Stress Evolution Of Anodic Alumina Films Prior To The Pore Formation, Ömer Özgür Çapraz, Shinsuke Ide, Pranav Shrotriya, Kurt R. Hebert

Society of Engineering Science 51st Annual Technical Meeting Archive

Porous anodic oxide (PAO) films are grown by electrochemical oxidation of metals in a solution that dissolve the oxide. During the film formation, voltage increases linearly until the peak, then declines to steady-state value. PAO finds extensive usage as templates and substrates in many applications, such as solar cells and optical devices. However, the mechanism underlying the observed initiation and evolution of self-organized PAO structure is not understood. Recent studies on pore formation points out the role of plastic flow on pore initiation process [1–3]. In this study, we characterized stress profiles and its evolution during the film formation prior …

Strain Mediated Nanoscale Transport In Nanostructured Carbon Materials, Md Hossain

Society of Engineering Science 51st Annual Technical Meeting Archive

Low-dimensional materials such as graphene or carbon nanotube show remarkable promise for next generation electronics (transistors), structural materials (composites), energy (thermoelectrics, solar cells), and biology (biosensors, drug delivery). However, owing to nanoscale dimension they are very susceptible to undergo mechanical deformation and respond to electronic interactions. As a result, their pristine properties are altered substantially in the vicinity of insulating substrates (on which they are grown), electrodes (that they are attached to) as well as external reactive molecules such as H2O. To quantify how deformation affects transport across the interface and how it couples with nanoscale deformation, this research uses …

Shape Optimization Of Microvascular Composites Used In Active Cooling Applications, Ahmad Raeisi Najafi, Marcus H.Y. Tan, Masoud Safdari, Philippe H. Geubelle

Society of Engineering Science 51st Annual Technical Meeting Archive

Inspired by microchannels networks in biological systems, microvascular composites are being used for various applications including active cooling, autonomic healing, and sensing. The recent development of a manufacturing technique for microvascular composites based on a sacrificial fiber approach has enabled the creation of complex networks of microchannels embedded in composite parts [1]. Motivated by these recent improvements in manufacturing of microvascular composites, we study design of an actively cooled composite plate. We examine the impact of microchannels configuration on the thermal response of the microvascular composite. Here, the composite plate is subjected to a heat flux that causes a high …

Phase Transforming Cellular Materials, David Restrepo, Pablo Zavattieri, Nilesh Makame

Society of Engineering Science 51st Annual Technical Meeting Archive

A phase transition is the transformation of a thermodynamic system from one phase to another. This transformation occurs in a wide range of structure and systems by the deformation of the crystal into a new structure changing the packing arrangement of the atoms in the unit cell. The different phases exhibit distinct properties and this change in the properties is exploited by technological innovations. Shape memory alloys are materials that present phase transformation alloys where martensitic phase transformation occurs by the deformation of the crystal into a new structure. A characteristic feature of the phase transformation in memory alloys is …

Wave Propagation In Random Fiberous Networks, Sahab Babaee, Pai Wang, Katia Bertoldi, Shervin Shahsavari, R. C. Picu

Society of Engineering Science 51st Annual Technical Meeting Archive

Random fiberous networks are ubiquitous in different length scales with a broad range of applications including biological tissues, paper, polymer transistors, protective clothing and packaging materials. Given the importance of fiber networks, their static behavior has been extensively studied and it has been shown that network deformation is nonaffine for compliant, low-density networks and affine for stiff, high-density networks. However, little is known about the dynamic response of fibrous systems. In this study, we investigated numerically the propagation of small-amplitude elastic waves in these random networks and characterize their dynamic response as a function of network parameters. Interestingly, our numerical …

On A Computational Framework To Model Material Degradation Due To Moisture, Temperature, And Chemical Reactions, Can Xu

Society of Engineering Science 51st Annual Technical Meeting Archive

Degradation is a major, widespread, and an important engineering problem. Its manifestations have been well known in infrastructure and various other real-life applications. This can be attributed to the fact that not only the durability of materials will be reduced, but also the material properties can be affected. For instance, thermal conductivity and diffusivity can change its behavior from isotropic to anisotropic because of the influence of material damage. Degradation can be caused by various mechanisms such as mechanical processes, chemical dissolution, oxidation, photolysis, biological effects, and radiation. Moreover, coupling effects between these mechanisms can have a significant impact on …

Thermal Fluctuations Of Biological Membranes, Pradeep Sharma, Fatemeh Ahmadpoor, Liping Liu, Yuranan Hanlumyuang

Society of Engineering Science 51st Annual Technical Meeting Archive

At physiological temperatures, most biological membranes noticeably fluctuate and these thermal fluctuations appear to govern an astounding array of biological functions: cell adhesion, membrane fusion, self-assembly, binding–unbinding transition among others. In this discussion, I will: (i) critically re-examine the entropic repulsive force between two fluctuating membranes and attempt to resolve a recent controversy on this issue, (ii) discuss the effect of curvature on thermal fluctuations and, (iii) discuss the connection between thermal fluctuations and electromechanical coupling in membranes –including implications for the minimum electric field that can be -detected by a cell.

Raman Thermometry Based Thermal Conductivity Measurement Of Bovine Cortical Bone As A Function Of Compressive Stress, Yang Zhang, Vikas Tomar

Society of Engineering Science 51st Annual Technical Meeting Archive

Biological materials such as bone have microstructure that incorporates a presence of a significant number of interfaces in a hierarchical manner that lead to a unique combination of properties such as toughness and hardness. However, studies regarding the influence of structural hierarchy on physical properties such as thermal conductivity and its correlation with mechanical stress of biomaterials are limited. Such studies can point out important insights regarding the role of biological structural hierarchy in influencing mechanophysical properties. This study presents an analytic-experimental approach to establish stress–thermal conductivity correlation in bovine cortical bone as a function of nanomechanical compressive stress using …

Potential Within: Topology Optimization Of The Spine, Ahmed Elbanna, Darin Peetz

Society of Engineering Science 51st Annual Technical Meeting Archive

As scientists and engineers continually seek to optimize systems and structures, biology has become an increasingly popular source of inspiration. Many common algorithms for optimization are based on natural phenomenon; therefore, it is only logical to assume that many natural structures are already optimally designed. In fact, Wolff’s law states that the trabecular structure of our own bones is a self-optimizing structure. This presentation explores that theory in relation to the vertebrae found in humans and animals alike.

The Wandering Spider Guild Of Webb County, Texas, Monica Trevino

Theses and Dissertations

Analysis of 10 years of spider collecting in Webb County, Texas has yielded 549 specimens in 21 genera and 55 species. This study was performed to establish similarities and relationships among wandering spiders of south Texas in Webb County and to identify the members of the wandering spider guild. The families included in this guild are the Clubionidae, Corinnidae, Gnaphosidae, Liocranidae, and Miturgidae. Wet pitfall traps and hand collecting were utilized in the gathering of the specimens. Spiders were identified using the most recent literature and allowed for an examination of the interactions of the members of this guild based …

The Santa Clara, 2014-10-02, Santa Clara University

The Santa Clara

No abstract provided.

10-02-2014 Swosu King And Queen Candidates To Be Narrowed To Three Finalists, Southwestern Oklahoma State University

THE BARK ARCHIVE 2014

Southwestern Oklahoma State University students will vote on Homecoming king and queen candidates this Friday, October 3.

The Utah Statesman, October 2, 2014, Utah State University

The Utah Statesman

Weekly student newspaper of Utah State University in Logan.

Western News, October 2, 2014, Western Michigan University

Western News (1972-2018)

Story highlights: WMU gets $3.2 million education grant; Enrollment down slightly; gains seen in key areas; Two to receive Distinguished Faculty Scholar Award; WMU earns its sixth consecutive ‘military friendly’ designation; On Campus with Gary and Sherry Sandlin.

October 2, 2014, James Madison University

The Breeze, 2010-2019

The Breeze is the student newspaper of James Madison University in Harrisonburg, Virginia.

The Scarlet - Volume Xciv, No. 4 (October 2, 2014), Scarlet Staff

The Scarlet (Student Newspaper) (2011-present)

The October 2, 2014 edition of The Scarlet (est. 1939), Clark University's student-run newspaper. The Scarlet is intellectually and editorially independent of the University.

Otter Realm, October 2, 2014, California State University, Monterey Bay

The Otter Realm

Viva La Herencia Hispanica! CSUMB Celebrates Chican@/Latin@ Heritage Month -- Seeing is Believing -- What You Otter Be Doing October 2 - October 15 -- Are You Afraid of the Dark? CSUMB Students Express Concerns About Campus Lighting and Safety -- Drop, Cover and Hold: Otters Prepare for the Great California Shakeout -- Not a Clear Ally: Students Face Challenges in Student Housing -- Serving Your World: Students Fulfill Service Learning Requirement Abroad -- Sirviendo Al Mundo: Estudiantes Hacen Su Servicio en Espana -- Viva La Herencia Hispanica! CSUMB Celebrates Chica@/Latin@ Heritage Month -- Sitting Pretty: Salinas SPCA Provides Happier …

Acute Repeated Intracerebroventricular Injections Of Angiotensin Ii Reduce Agonist And Antagonist Radioligand Binding In The Paraventricular Nucleus Of The Hypothalamus And Median Preoptic Nucleus In The Rat Brain, Robert C. Speth, Peter J. Vento, Eduardo J. Carrera, Luz Gonzalez-Reily, Andrea Linares, Kira Santos, Jamala D. Swindle, Derek Daniels

HPD Articles

Angiotensin II (Ang II) stimulates water and saline intakes when injected into the brain of rats. This arises from activation of the AT1 Ang II receptor subtype. Acute repeated injections, however, decrease the water intake response to Ang II without affecting saline intake. Previous studies provide evidence that Ang II-induced water intake is mediated via the classical G protein coupling pathway, whereas the saline intake caused by Ang II is mediated by an ERK 1/2 MAP kinase signaling pathway. Accordingly, the different behavioral response to repeated injections of Ang II may reflect a selective effect on G protein coupling. To …

Universal Assessment Challenges In Healthcare Related Education, Jane M. Souza

Educational Effectiveness Assessment Faculty/Staff Publications

Webinar Description:

Whether you are accountable to the American Council on Pharmacy Education, the Standards for Accreditation of Medical Education Programs Leading to the MD Degree, the World Federal Medical Education Standards, or any other accrediting agency, you have no doubt seen the increased emphasis on the use of student outcomes data. The call to articulate formal program objectives and track assessment of student achievement on those objectives is universal. This webinar will demonstrate how the learning analytics capabilities of ExamSoft can be used to address both didactic and experiential objectives to serve multiple purposes including remediation, curriculum development, and …

Neurolunch: Incorporation Of Inwardly Rectifying Ampa Receptors At Silent Synapses During Hippocampal Long-Term Potentiation, Oct. 2, Ohio University College Of Arts & Sciences

All Forum Articles

No abstract provided.

The Gazette October 2, 2014, Langston University

LU Gazette, 2010-2019

The student newspaper for Langston University