Mechanical Engineering Commons^™

Cosolvent Incorporation Modulates The Thermal And Structural Response Of Pnipam/Silyl Methacrylate Copolymers, Jason D. Linn, Fabian A. Rodriguez, Michelle A. Calabrese

Mechanical Engineering Faculty Publications

Polymers functionalized with inorganic silane groups have been used in wide-ranging applications due to the silane reactivity, which enables formation of covalently-crosslinked polymeric structures. Utilizing stimuli-responsive polymers in these hybrid systems can lead to smart and tunable behavior for sensing, drug delivery, and optical coatings. Previously, the thermoresponsive polymer poly(N-isopropyl acrylamide) (PNIPAM) functionalized with 3-(trimethoxysilyl)propyl methacrylate (TMA) has demonstrated unique aqueous self-assembly and optical responses following temperature elevation. Here, we investigate how cosolvent addition, particularly ethanol and N,N-dimethyl formamide (DMF), impacts these transition temperatures, optical clouding, and structure formation in NIPAM/TMA copolymers. Versus purely aqueous …

Lamina Cribrosa Insertions Into The Sclera Are Sparser, Narrower, And More Slanted In The Anterior Lamina, Fengting Ji, Mohammad R. Islam, Bingrui Wang, Yi Hua, Ian A. Sigal

Mechanical Engineering Faculty Publications

Purpose: The lamina cribrosa (LC) depends on the sclera for support. The support must be provided through the LC insertions. Although a continuous insertion over the whole LC periphery is often assumed, LC insertions are actually discrete locations where LC collagenous beams meet the sclera. We hypothesized that LC insertions vary in number, size, and shape by quadrant and depth.

Methods: Coronal cryosections through the full LCs from six healthy monkey eyes were imaged using instant polarized light microscopy. The images were registered into a stack, on which we manually marked LC insertion outlines, nothing their position in-depth and quadrant …

Existence Of A Nonzero Worst-Case Ach For Short-Term Exposure In Ventilated Indoor Spaces, K. A. Krishnaprasad, ‪Nadim Zgheib, K. Choudhary, M. Y. Ha, C. Y. Choi, K. S. Bang, S. Jang, S. Balachandar

Mechanical Engineering Faculty Publications

A well-ventilated room is essential to reduce the risk of airborne transmission. As such, the scientific community sets minimum limits on ventilation with the idea that increased ventilation reduces pathogen concentration and thus reduces the risk of transmission. In contrast, the upper limit on ventilation is usually determined by human comfort and the need to reduce energy consumption. While average pathogen concentration decreases with increased ventilation, local concentration depends on multiple factors and may not follow the same trend, especially within short exposure times over large separation distances. Here, we show through experiments and high-fidelity simulations the existence of a …

Characterization Of Microstructural And Mechanical Properties Of 17-4 Ph Stainless Steel By Cold Rolled And Machining Vs. Dmls Additive Manufacturing, Pablo Moreno-Garibaldi, Melvyn Alvarez-Vera, Juan Alfonso Beltrán-Fernández, Rafael Carrera-Espinoza, Héctor Manuel Hdz-García, J. C. Díaz-Guillen, Rita Muñoz-Arroyo, Javier A. Ortega, Paul Molenda

Mechanical Engineering Faculty Publications

The 17-4 PH stainless steel is widely used in the aerospace, petrochemical, chemical, food, and general metallurgical industries. The present study was conducted to analyze the mechanical properties of two types of 17-4 PH stainless steel—commercial cold-rolled and direct metal laser sintering (DMLS) manufactured. This study employed linear and nonlinear tensile FEM simulations, combined with various materials characterization techniques such as tensile testing and nanoindentation. Moreover, microstructural analysis was performed using metallographic techniques, optical microscopy, scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD). The results on the microstructure for 17-4 PH DMLS stainless steel reveal …

Multilayer Pva/Gelatin Nanofibrous Scaffolds Incorporated With Tanacetum Polycephalum Essential Oil And Amoxicillin For Skin Tissue Engineering Application, Ebrahim Soleiman-Dehkordi, Vahid Reisi-Vanani, Samanesadat Hosseini, Zahra Lorigooini, Vajihe Azimian Zvareh, Mahour Farzan, Elham Moghtadaie Khorasgani, Karen Lozano, Zohreh Abolhassanzadeh

Mechanical Engineering Faculty Publications

Wound infection is still an important challenge in healing of different types of skin injuries. This highlights the need for new and improved antibacterial agents with novel and different mechanisms of action. In this study, by electrospinning process Tanacetum polycephalum essential oil (EO), as a natural antibacterial and anti-inflammatory agent, along with Amoxicillin (AMX) as an antibiotic are incorporated into PVA/gelatin-based nanofiber mats individually and in combination to fabricate a novel wound dressing. Briefly, we fabricated PVA/gelatin loaded by Amoxicillin as first layer for direct contact with wound surface to protects the wound from exogenous bacteria, and then built a …

Wire Texture C-Axis Distribution Of Strontium Ferrite/Pa-12 Extruded Filament, Gabriela Espinosa-Rodriguez, Oluwasola Arigbabowo, Jonathan Alvarado, Jitendra Tate, Wilhelmus J. Geerts

Mechanical Engineering Faculty Publications

The magnetic anisotropy of strontium ferrite (SF)/PA12 filament, a popular hard magnetic ferrimagnetic composites that is used for 3D-printing of permanent magnets, is studied by vibrating sample magnetometry. The studied filaments have a composition of SF/PA-12 thermoplastic composite with a 40% wt.  ratio of SF. SF particles are non-spherical platelets with an average diameter of 1.3 um and a diameter to thickness ratio of 3. Filaments are produced by a twin-screw extruder and have a diameter of 1.5 mm. SEM images show that the SF particles are homogeneously distributed through the filament. VSM measurements on different parts of the filaments …

Reduced Order Model Of Parametric Resonance Of Electrostatically Actuated Cantilever Resonators: Comparison Uniform Versus Non-Uniform Resonators, Dumitru I. Caruntu, Rigoberto Flores

Mechanical Engineering Faculty Publications

A comparison of the frequency-amplitude and voltage-amplitude responses of parametric resonance between electrostatically actuated uniform and non-uniform cantilever resonator is conducted. The non-uniform cantilever resonator has constant width and linearly varying thickness. Both microstructures uniform and non-uniform are under soft AC electrostatic actuation. Two Reduced Order Models for predicting the responses of the MEMS cantilever are used in this paper, namely one using one mode of vibration, and another one using two modes of vibration. The Method of Multiple Scales is used to solve the Reduced Order Model with one mode of vibration. A second method is a direct numerical …

Assessing The Lubrication Performance Of Sunflower Oil Modified With Montmorillonite Clay (Mmt) Nanoparticles For Industrial Applications, Md Mashfiqur Rahman, Md Abu Sayeed Biswas, Laura Peña-Pará, Demófilo Maldonado- Cortés, Javier A. Ortega

Mechanical Engineering Faculty Publications

Because of the environmental impact and price volatility, there has been a growing concern about using petroleum-based lubricants. This issue has encouraged research into the development of biodegradable lubricants like vegetable oils. This study assessed the tribological behavior of sunflower oil modified with Montmorillonite nanoclay (MMT) as lubricant additives. A block-on-ring tribometer was used to assess the wear and friction characteristics of the nano-lubricants. A custom-made tapping torque tester was used to evaluate the nano-lubricants in a real-world application. It was found that the volumetric wear, Coefficient of Friction, and torque of the system decreased when MMT nanoparticles were added. …

Predicting Oscillatory Patterns Of Mud Circulating Along The Well-Bore In Drilling Procedures: A Finite Element Model, Eleazar Marquez

Mechanical Engineering Faculty Publications

In this paper, a mathematical model is proposed to further understand the dynamic effects [drilling] mud exerts on the drill-string assembly. The proposed model consists of a rotor subjected to various revolutions per minute (RPM’s), an axial force which accounts for the weight-on bit requirements, and a harmonic excitation simulating fluid mud circulating along the well-bore. In this regard, Euler-Bernoulli beam theory is incorporated to establish a multi-degree-of-freedom (MDOF) mathematical expression of a specific section of the BHA. In this regard, a finite element methodology was implemented to determine the corresponding parameters of the equation of motion and elucidate the …

Modelling Of A Drone To Analyze Dynamic Instabilities With Its Delivery System, Eleazar Marquez, Ivan Luna

Mechanical Engineering Faculty Publications

In the study herein, an alternative mathematical model was developed with the intention of understanding the dynamics associated with the instabilities generated by an UAV and its delivery system, particularly the coupled nonlinearities of the system, and thus provide feedback to optimize drone design. In this regard, a Newton-Euler methodology was adopted to establish the parameters of the equations of motion of the target UAV system, which consisted of a combination of a platform and delivery system operating simultaneously. Specifically, the UAV platform was modelled as a rigid body which accounted for a total of six-degrees-of-freedom, three corresponding to the …

Graphene Reinforced Pvdf Nanofibers Fabricated With The Forcespinning® Method For Water Desalination Applications, Elmmer A. Vera Alvarado, Md. Abdur Rahman Bin Abdus Salam, Ali Ashraf, Karen Lozano

Mechanical Engineering Faculty Publications

Direct contact membrane distillation (DCMD) is a thermally driven energy and cost-efficient desalination technique where low-grade energy from solar or waste heat from plants can be used to recover fresh water from high saline water. The DCMD technique allows both the feed and permeate solutions to be in contact with the membrane, where vapor from the feed gets condensed in the permeate side once it collides with low- temperature water. Polyvinylidene fluoride (PVDF) nanofiber membranes were prepared by the ForceSpinning® method, these were later dip coated in graphene solutions prepared with different solvents. The ForceSpinning® method, unlike electrospinning, operates in …

In-Situ Shear Exfoliation Of Graphene From Graphite Polymer Nanocomposites For Lung And Heart Motion, Md Ashiqur Rahman, Md Abdur Rahman Bin Abdus Salam, Ali Ashraf

Mechanical Engineering Faculty Publications

Graphene-based nanocomposites have become attractive for different applications such as energy storage, sensors, biomolecule detection, biomedical, healthcare, and wearable devices due to their unique mechanical, electrical, and thermal properties. However, using commercial graphene for making nanocomposite devices can be expensive, and fabricating nanocomposites can be challenging due to impurities while transferring graphene to elastomer composites. In this study, we used a simple, inexpensive in-situ shear exfoliation method to produce graphene from graphite directly within the elastomer. As the graphene in the elastomer reached beyond its percolation or threshold, electrons hop or tunnel around from one graphene flake to another. So, …

Identifying Sick Cells From High-Resolution Solid-State Micropore Data, Abdul Hafeez, Azhar Ilyas, Ali R. Butt, Samir M. Iqbal

Mechanical Engineering Faculty Publications

Early detection of diseases such as cancer can drastically improve prognosis and treatment. To this end, solid-state micropores can measure distinct mechanical properties of diseased cells from their translocation behavior — detected as pulses in the temporal data stream of ionic current — and help diagnose diseases at early stages. However, the obstacle in such approaches is that the accuracy of the sensor is affected by noise, making the pulse detection task too subjective. This is inefficient especially when the disease-relevant data is only a fraction of the total acquired data. Thus, it is important to intelligently automate the detection …

Effect Of Foot Additional Mass On The Clinical Angles Of Knee Extension Exercise, Dumitru I. Caruntu, Alfirio Trejo, Eric Rodriguez, Camila T. Alvarez B

Mechanical Engineering Faculty Publications

This study investigates the effect of foot additional mass on the abduction and internal rotation knee angles during knee extension exercise. Three subjects (two male and one female) performed four sets of ten repetitions of the knee extension exercise for the right leg. For the first set, the subject performed the exercise with no additional weight. For each set after, weight was added around the subject’s right foot and the subject was allowed a rest period before beginning the next set. The weights for sets 1, 2, 3, and 4 were 0.00kg (no additional weight) ,0.82kg, 1.64kg, and 2.27kg respectively. …

Fibrous Finite Element Modeling Of The Optic Nerve Head Region, Mohammad R. Islam, Fengting Ji, Manik Bansal, Yi Hua, Ian A. Sigal

Mechanical Engineering Faculty Publications

The optic nerve head (ONH) region at the posterior pole of the eye is supported by a fibrous structure of collagen fiber bundles. Discerning how the fibrous structure determines the region biomechanics is crucial to understand normal physiology, and the roles of biomechanics on vision loss. The fiber bundles within the ONH structure exhibit complex three-dimensional (3D) organization and continuity across the various tissue components. Computational models of the ONH, however, usually represent collagen fibers in a homogenized fashion without accounting for their continuity across tissues, fibers interacting with each other and other fiber-specific effects in a fibrous structure. We …

Computational Modelling Of A Triaxial Vibrating Sample Magnetometer, Leo Rodriguez, Arjun Sapkota, Jonathan Alvarado, Jitendra S. Tate, Wilhelmus J. Geerts

Mechanical Engineering Faculty Publications

Magnetic Field Assisted Additive Manufacturing (MFAAM) enables 3D printing of magnetic materials of various shapes which exhibit a complex anisotropy energy surface containing contributions generated from different origins such as sample, particle, and agglomerate shape anisotropy, flow and field induced anisotropy, and particle crystal anisotropy. These novel magnet shapes require the need to measure the x, y, and z components of the magnetic dipole moment simultaneously to fully understand the magnetic reversal mechanism and unravel the complex magnetic anisotropy energy surface of 3D printed magnetic composites. This work aims to develop a triaxial vibrating sample magnetometer (VSM) by adding a …

An Automated On-The-Go Unloading System Reduces Harvest Operator Stress Relative To Manual Operation, Travis A. Burgers, Kusha Kamarei, Mukund Vora, Matthew Horne

Mechanical Engineering Faculty Publications

On-the-go unloading improves harvest operational efficiency, but it requires skilled labor because it is challenging and stressful to balance numerous concurrent tasks. Harvest automation reduces workload, stress, and fatigue. The objective of this study was to determine if using a commercially available, automated on-the-go unloading system (Raven Cart Automation TM , RCA, Raven Industries) would reduce operator stress com- pared to manual operation. Nine grain cart tractor operators and six combine operators participated in this study. Operators performed their typical harvest operation, except to alternate on-the-go unloading using RCA or operating manually. Skin conductance (elec- trodermal activity) was measured with …

Near-Optimal Trajectory Tracking In Quadcopters Using Reinforcement Learning, Randal Engelhardt, Alberto Velazquez, Tohid Sardarmehni

Mechanical Engineering Faculty Publications

The control of quadcopters poses significant challenges due to their complex dynamics characterized by highly nonlinear couplings, high system order, and under-actuation. This paper presents a novel control solution aimed at achieving near-optimal trajectory tracking for quadcopters. A near-optimal solution based on approximate dynamic programming is proposed to address the curse of dimensionality inherent in traditional dynamic programming, employing a single network adaptive critic. Extensive simulations validate the effectiveness and robustness of the proposed solution.

Functionalized Thermoplastic Polyurethane Nanofibers: An Innovative Triboelectric Energy Generator, Julia I. Salas, Diego De Leon, Sk Shamim Hasan Abir, Mohammed Jasim Uddin, Karen Lozano

Mechanical Engineering Faculty Publications

A triboelectric nanogenerator (TENG) is one of the most significantly innovative microdevices for built-in energy harvesting with wearable and portable electronics. In this study, the forcespinning technology was used to synthesize a nanofiber (NF) mat-based TENG. Polyvinylidene fluoride (PVDF) membrane was used as the negative triboelectric electrode/pole, and chemically designed and functionalized thermoplastic polyurethane (TPU) was used as the positive electrode/pole for the TENG. The electronic interference, sensitivity, and gate voltage of the synthesized microdevices were investigated using chemically modified bridging of multi-walled carbon nanotubes (MWCNT) with a TPU polymer repeating unit and bare TPU-based positive electrodes. The chemical functionality …

Mems Cantilever Biosensors Driven By Fringe Effect: Voltage-Amplitude Response Of Parametric Resonance, Miguel A. Martinez, Dumitru I. Caruntu

Mechanical Engineering Faculty Publications

This paper deals with voltage-amplitude response of fringing field/effect actuated micro-electromechanical system (MEMS) cantilever beam resonator biosensors at parametric resonance. The system consists of a flexible electrode (cantilever beam) and a fixed electrode (ground plate) in parallel, connected through an AC voltage source. The electrostatic force induced is due to the parallel-plate capacitance, which is directly related to the overlapping area of the two electrodes (Palmer’s Formula). In addition, fringing field electrostatic actuation must be accounted for. This is due to the bending of electric field lines from the ground plate to the top and side walls of the cantilever …

Amplitude-Voltage Response Of Parametric Resonance Of Electrostatically Actuated Circular Membranes, Marcos Alipi, Dumitru I. Caruntu

Mechanical Engineering Faculty Publications

This paper deals with the amplitude-voltage response of parametric resonance of electrostatically actuated MEMS circular membranes resonator for sensing applications. The system consists of a flexible circular membrane over a parallel ground plate. A soft AC voltage is applied between the MEMS membrane and ground plate to actuate the membrane near its first natural frequency. Two methods of investigation are used in this research, namely the method of multiple scales (MMS), and the reduced order model (ROM). These methods were used to solve for the voltage response of the MEMS analytically and numerically. This work also reports the effects the …

Thermal Transport And Rheological Properties Of Hybrid Nanofluids Based On Vegetable Lubricants, Helio Ribeiro, Jaime Taha-Tijerina, Ofelia Gomez, Ever Acosta, Gabriel M. Pinto, Lorena R. C. Moraes, Guilhermino J. M. Fechine, Ricardo J. E. Andrade, Jefferson Reinoza, Victoria Padilla, Karen Lozano

Mechanical Engineering Faculty Publications

Nanofluids based on vegetal oil with different wt.% of carbon nanotubes (CNT), hexagonal boron nitride (h-BN), and its hybrid (h-BN@CNT) were produced to investigate the effects of these nano-additives on the thermal conductivity and rheological properties of nanofluids. Stable suspensions of these oil/nanostructures were produced without the use of stabilizing agents. The dispersed nanostructures were investigated by SEM, EDS, XRD, and XPS, while the thermal conductivity and rheological characteristics were studied by a transient hot-wire method and steady-state flow tests, respectively. Increases in thermal conductivity of up to 39% were observed for fluids produced with 0.5 wt.% of the hybrid …

Development Of Pullulan/Chitosan/Salvianolic Acid Ternary Fibrous Membranes And Their Potential For Chemotherapeutic Applications, Salahuddin Ahmed, Megan Keniry, Victoria Padilla, Narcedalia Anaya-Barbosa, Md Noushad Javed, Robert Gilkerson, Kithzia Gomez, Acharan S. Narula, Karen Lozano

Mechanical Engineering Faculty Publications

This study investigates the feasibility of centrifugal spinning for producing fibrous membranes containing pullulan, chitosan, and danshen extract. The danshen extract is composed of 20 wt% salvianolic acid B (SA). Citric acid was added to the mixture as a crosslinking agent to promote its use in the aqueous medium. The influence of the danshen concentration (25 wt% and 33 wt%) on fiber morphology, thermal behavior, and the biochemical effect was analyzed. Developed fiber-based membranes consist of long, continuous, and uniform fibers with a sparse scattering of beads. Fiber diameter analysis shows values ranging from 384 ± 123 nm to 644 …

Effect Of Room Size, Shape, Ac Placement, And Air Leakage On Indoor Airborne Viral Transmission, K. Choudhary, K. A. Krishnaprasad, ‪Nadim Zgheib, M. Y. Ha, S. Balachandar

Mechanical Engineering Faculty Publications

Highlights

• Statistical overloading is used to obtain spatio-temporal pathogen concentration.

• Symmetrically placed AC limits pathogen propagation over long distances.

• Well-mixed model captures room-averaged concentration for any shape and AC location.

• The pathogens level of mixing is reduced when AC is symmetrically positioned.

• Air leakage has insignificant impact on indoor pathogen distribution.

Abstract

We conducted Euler–Lagrange Reynolds-Averaged Navier–Stokes simulations with statistical overloading to investigate the effect of room shape, air-condition (AC) location, and the presence of an open window on indoor airborne viral transmission, particularly as it relates to the spatio-temporal distribution of viral-laden droplet nuclei. Two room geometries were …

A Facile Graphene Conductive Polymer Paper Based Biosensor For Dopamine, Tnf-Α, And Il-6 Detection, Md Ashiqur Rahman, Ramendra Kishor Pal, Nazmul Islam, Robert Freeman, Francois Berthiaume, Aaron Mazzeo, Ali Ashraf

Mechanical Engineering Faculty Publications

Paper-based biosensors are a potential paradigm of sensitivity achieved via microporous spreading/microfluidics, simplicity, and affordability. In this paper, we develop decorated paper with graphene and conductive polymer (herein referred to as graphene conductive polymer paper-based sensor or GCPPS) for sensitive detection of biomolecules. Planetary mixing resulted in uniformly dispersed graphene and conductive polymer ink, which was applied to laser-cut Whatman filter paper substrates. Scanning electron microscopy and Raman spectroscopy showed strong attachment of conductive polymer-functionalized graphene to cellulose fibers. The GCPPS detected dopamine and cytokines, such as tumor necrosis factor-alpha (TNF-α), and interleukin 6 (IL-6) in the ranges of 12.5–400 …

Multifunctional Graphene–Polymer Nanocomposite Sensors Formed By One-Step In Situ Shear Exfoliation Of Graphite, Ali Ashraf, Elizabeth Chang, Md Ashiqur Rahman, Dipannita Ghosh, Nazmul Islam, Jennifer K. Lynch-Branzoi

Mechanical Engineering Faculty Publications

Graphene nanocomposites are a promising class of advanced materials for sensing applications; yet, their commercialization is hindered due to impurity incorporation during fabrication and high costs. The aim of this work is to prepare graphene–polysulfone (G−PSU) and graphene–polyvinylidene fluoride (G−PVDF) nanocomposites that perform as multifunctional sensors and are formed using a one-step, in situ exfoliation process whereby graphite is exfoliated into graphene nanoflakes (GNFs) directly within the polymer. This low-cost method creates a nanocomposite while avoiding impurity exposure since the raw materials used in the in situ shear exfoliation process are graphite and polymers. The morphology, structure, thermal properties, and …

Extrusion Of Uniform-Diameter Polyetheretherketone-Magnesium Phosphate Bio-Composite Filaments For 3d Printing Of Design-Specific Multi-Functional Implants, Vijay K. Bokam, Surendrasingh Y. Sonaye, Phaniteja Nagaraju, Harsha P.S. Naganaboyina, Prabaha Sikder

Mechanical Engineering Faculty Publications

Polyetheretherketone (PEEK) is a high-performance polymer material for developing implants for orthopedic, spinal, cranial, maxillofacial, and dentistry applications. However, the major limitation of PEEK implants is their bioinertness, i.e., their incapability to integrate with tissues. Therefore, prior efforts have always focused on developing hydroxyapatite (HA) coatings on PEEK or PEEK-HA composites. However, in this study, we engineered a highly novel bioceramic known as amorphous magnesium phosphate (AMP), which surpasses the bioactivity and biodegradation kinetics of HA. Subsequently, we incorporated AMP in PEEK to develop a unique PEEK-AMP bioactive composite in the form of uniform-diameter filaments, such that it can be …

Regulating The Size And Assembled Structure Of Graphene Building Blocks For High-Performance Silicon Nanocomposite Anodes, Bo Nie, David Sanchez, Mataz Alcoutlabi, Tengxiao Liu, Saurabh Basu, Soundar Kumara, Gongkai Wang, Hongtao Sun

Mechanical Engineering Faculty Publications

Silicon-based composites have received significant interest as a high-capacity anode material for high-performance lithium-ion batteries. However, the large volume change during prolonged charge/discharge cycles, poor electric conductivity, and unstable solid electrolyte interface of the Si electrodes lead to performance degradations, such as fast capacity decay and low coulombic efficiency (CE). It's promising but challenging to fabricate Si-based composite anodes with a high Si active material, which enables high energy density, high-rate capability, and good cycling stability. Herein, the size effect of mechanically robust and highly conductive graphene sheets was investigated to effectively regulate the charge transport kinetics, volume changes, first …

Effect Of Nanoparticle Loading And Magnetic Field Application On The Thermodynamic, Optical, And Rheological Behavior Of Thermoresponsive Polymer Solutions, Christopher A. P. Neal, Grace V. Kresge, Michelle C. Quan, Valeria León, Nondumiso O. Chibambo, Michelle A. Calabrese

Mechanical Engineering Faculty Publications

Although processing via external stimuli is a promising technique to tune the structure and properties of polymeric materials, the impact of magnetic fields on phase transitions in thermoresponsive polymer solutions is not well-understood. As nanoparticle (NP) addition is also known to impact these thermodynamic and optical properties, synergistic effects from combining magnetic fields with NP incorporation provide a novel route for tuning material properties. Here, the thermodynamic, optical, and rheological properties of aqueous poly(N-isopropyl acrylamide) (PNIPAM) solutions are examined in the presence of hydrophilic silica NPs and magnetic fields, individually and jointly, via Fourier-transform infrared spectroscopy (FTIR), magneto-turbidimetry, …

A Direct Fiber Approach To Model Sclera Collagen Architecture And Biomechanics, Fengting Ji, Manik Bansal, Bingrui Wang, Yi Hua, Mohammad R. Islam, Felix Matuschke, Markus Axer, Ian A. Sigal

Mechanical Engineering Faculty Publications

Sclera collagen fiber microstructure and mechanical behavior are central to eye physiology and pathology. They are also complex, and are therefore often studied using modeling. Most models of sclera, however, have been built within a conventional continuum framework. In this framework, collagen fibers are incorporated as statistical distributions of fiber characteristics such as the orientation of a family of fibers. The conventional continuum approach, while proven successful for describing the macroscale behavior of the sclera, does not account for the sclera fibers are long, interwoven and interact with one another. Hence, by not considering these potentially crucial characteristics, …