Other Engineering Science and Materials Commons^™

Scalar Differential Equation For Slowly-Varying Thickness-Shear Modes In At-Cut Quartz Resonators With Surface Impedance For Acoustic Wave Sensor Application, Huijing He, Jiashi Yang, John A. Kosinski

Department of Mechanical and Materials Engineering: Faculty Publications

For time-harmonic motions, we generalize a 2-D scalar differential equation derived previously by Tiersten for slowly-varying thickness-shear vibrations of AT-cut quartz resonators. The purpose of the generalization is to include the effects of surface acoustic impedance from, e.g., mass layers or fluids for sensor applications. In addition to the variation of fields along the plate thickness, which is considered in the usual 1-D acoustic wave sensor models, the equation obtained also describes in-plane variations of the fields, and therefore can be used to study the vibrations of finite plate sensors with edge effects. The equation is compared with the theory …

A New Angle On Microscopic Suspension Feeders Near Boundaries, Rachel E. Pepper, Marcus Roper, Sangjin Ryu, Nobuyoshi Matsumoto, Moeto Nagai, Howard A. Stone

Department of Mechanical and Materials Engineering: Faculty Publications

Microscopic sessile suspension feeders are a critical component in aquatic ecosystems, acting as an intermediate trophic stage between bacteria and higher eukaryotic taxa. Because they live attached to boundaries, it has long been thought that recirculation of the feeding currents produced by sessile suspension feeders inhibits their ability to access fresh fluid. However, previous models for the feeding flows of these organisms assume that they feed by pushing fluid perpendicular to surfaces they live upon, whereas we observe that sessile suspension feeders often feed at an angle to these boundaries. Using experiments and calculations, we show that living suspension feeders …

Pan Nanofibers And Nanofiber Reinforced Composites, Cheng Ren

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Nanomaterials play an important role in the development of nanotechnology. They possess unique mechanical, physical, and chemical properties coupled with small size and ultrahigh surface area that can provide critical advantages for applications. Continuous nanofibers attract special interest due to their dual nano-macro nature and ability to bridge scales. Nanofibers are being considered for a broad range of applications spanning advanced filters, separation membranes, ultrasensitive sensors, micro/nano actuators, nanoprobes, tissue engineering scaffolds, protective and smart closing, and multifunctional composites. Most of these applications require certain mechanical properties and robustness. However, the literature on the mechanical behavior of nanofibers and their …

Materials Education And Research In Art And Design: A New Role For Libraries (Survey Stats), Mark Pompelia

Materials Education and Research in Art and Design: A New Role for Libraries

No abstract provided.

Materials Education And Research In Art And Design: A New Role For Libraries (Program Sheet), Mark Pompelia

Materials Education and Research in Art and Design: A New Role for Libraries

No abstract provided.

Materials Education And Research In Art And Design: A New Role For Libraries (Program Booklet), Mark Pompelia

Materials Education and Research in Art and Design: A New Role for Libraries

No abstract provided.

Materials Education And Research In Art And Design: A New Role For Libraries (Website), Mark Pompelia

Materials Education and Research in Art and Design: A New Role for Libraries

No abstract provided.

Materials Collection Creation And Administration: A New Role For Libraries (White Paper), Mark Pompelia

Materials Education and Research in Art and Design: A New Role for Libraries

The Problem/Opportunity: To define, identify, and guide design-based materials collections in academic settings and foster community among those with existing collections and/or those considering creating and supporting one.

Contents and topics:

1. What is a materials collection?
2. Why have a materials collection?
3. Acquisition strategies
4. Organizational approaches
5. Programming possibilities
6. Symposium summary
7. Resources

Thickness-Shear And Thickness-Twist Vibrations Of Circular At-Cut Quartz Resonators, Huijing He, Jiashi Yang, Qing Jiang

Department of Mechanical and Materials Engineering: Faculty Publications

Exact solutions for free vibration frequencies and modes are obtained for thickness-shear and thickness-twist vibrations of unelectroded circular AT-cut quartz plates governed by the two-dimensional scalar differential equation derived by Tiersten and Smythe. Comparisons are made with experimental results and the widely-used perturbation solution by Tiersten and Smythe under the assumption of weak in-plane anisotropy. Our solution is found to be much closer to the experimental results than the perturbation solution . For the frequency of the fundamental thickness- shear mode, the error of the perturbation method is 0.4549%, significant in resonator applications.

Plastic Deformation Of Astm A36 Steel Using Two-Stage Light Gas Gun, Shawoon Kumar Roy

College of Engineering: Graduate Celebration Programs

To characterize material deformation in high velocity impact. To validate material models for computation simulation purposes.

This ongoing research is an attempt to study the plastic deformation of A36 steel plate (0.5” thick) under hypervelocity impact. Plastic deformation of the target plate was simulated using finite element software LS-DYNA.

Analysis Of Bolted Joints Under Medium And High Impact Loading, Deepak Sankar Somasundaram, Mohamed Trabia, Brendan J. O'Toole

College of Engineering: Graduate Celebration Programs

• Develop test fixture for medium impact study on bolted joints
• Create FEA model that can replicate the experiment
• Develop test fixture for high impact loading
• Create FEA model and select material properties that can produce results that
  closely match experiments.
• Compare different modeling techniques for high impact loading

High-Resolution Correlation Spectroscopy Of 13c Spins Near A Nitrogen-Vacancy Centre In Diamond, Abdelghani Laraoui, Florian Dolde, Christian Burk, Friedemann Reinhard, Jorg Wrachtrup, Carlos A. Meriles

Department of Mechanical and Materials Engineering: Faculty Publications

Spin complexes comprising the nitrogen-vacancy centre and neighbouring spins are being considered as a building block for a new generation of spintronic and quantum information processing devices. As assembling identical spin clusters is difficult, new strategies are being developed to determine individual node structures with the highest precision. Here we use a pulse protocol to monitor the time evolution of the 13C ensemble in the vicinity of a nitrogenvacancy centre. We observe long-lived time correlations in the nuclear spin dynamics, limited by nitrogen-vacancy spin–lattice relaxation. We use the host 14N spin as a quantum register and demonstrate that hyperfine-shifted resonances …

Thickness-Shear Vibration Of A Rectangular Quartz Plate With Partial Electrodes, Huijing He, Jiashi Yang, John A. Kosinski, Ji Wang

Department of Mechanical and Materials Engineering: Faculty Publications

We study free vibration of a thickness-shear mode crystal resonator of AT-cut quartz. The resonator is a rectangular plate partially and symmetrically electroded at the center with rectangular electrodes. A single-mode, three-dimensional equation governing the thickness-shear displacement is used. A Fourier series solution is obtained. Numerical results calculated from the series show that there exist trapped thickness-shear modes whose vibration is mainly under the electrodes and decays rapidly outside the electrodes. The effects of the electrode size and thickness on the trapped modes are examined.

Room-Temperature Organic Ferromagnetism In The Crystalline Poly(3-Hexylthiophene): Phenyl-C61-Butyric Acid Methyl Ester Blend Film, Bin Yang, Zhengguo Xiao, Yongbo Yuan, Tanjore V. Jayaraman, Jeffrey E. Shield, Ralph Skomski, Jinsong Huang

Department of Mechanical and Materials Engineering: Faculty Publications

Pronounced ferromagnetism was observed in a crystalline blend film of conjugated polymer poly(3-hexylthiophene) (P3HT) and phenyl-C61-butyric acid methyl ester (PCBM) by using magnetic force microscopy measurements. A substantial room-temperature saturation magnetization of about 0.65 emu g−1 was measured by an alternating gradient field magnetometer. Multiple experimental evidences demonstrate the charge transfer from the P3HT to the PCBM and the formation of P3HT crystal domain are expected to be two critical factors for the originals of room-temperature organic ferromagnetism.

A Mathematical Evaluation Of Hemodynamic Parameters After Carotid Eversion And Conventional Patch Angioplasty, Alexey Kamenskiy, Iraklis I. Pipinos, Yuris A. Dzenis, Prateek K. Gupta, Syed A. Jaffar Kazmi, Jason N. Mactaggart

Department of Mechanical and Materials Engineering: Faculty Publications

Carotid endarterectomy has a long history in stroke prevention, yet controversy remains concerning optimal techniques. Two methods frequently used are endarterectomy with patch angioplasty (CEAP) and eversion endarterectomy (CEE). The objective of this study was to compare hemodynamics-related stress and strain distributions between arteries repaired using CEAP and CEE. Mathematical models were based on in vivo three-dimensional arterial geometry, pulsatile velocity profiles, and intraluminal pressure inputs obtained from 16 patients with carotid artery disease. These data were combined with experimentally derived nonlinear, anisotropic carotid artery mechanical properties to create fluid-structure interaction models of CEAP and CEE. These models were then …

Effects Of Mode Coupling On The Admittance Of An At-Cut Quartz Thickness-Shear Resonator, Huijing He, Jiashi Yang, Wei-Ping Zhang, Ji Wang

Department of Mechanical and Materials Engineering: Faculty Publications

We study the effects of couplings to flexure and face-shear modes on the admittance of an AT-cut quartz plate thickness-shear mode resonator. Mindlin’s two-dimensional equations for piezoelectric plates are employed. Electrically forced vibration solutions are obtained for three cases: pure thickness-shear mode alone; two coupled modes of thickness shear and flexure; and three coupled modes of thickness shear, flexure, and face shear. Admittance is calculated and its dependence on the driving frequency and the length/thickness ratio of the resonator is examined. Results show that near the thickness-shear resonance, admittance assumes maxima, and that for certain values of the length/thickness ratio, …

A Comparative Study Of The Dry And Wet Nano-Scale Electro-Machining, M. P. Jahan, K. R. Virwani, Kamlakar P. Rajurkar, A. P. Malshe

Department of Mechanical and Materials Engineering: Faculty Publications

In recent years, a nano-electromachining (nano-EM) process based on a scanning tunneling microscope (STM) platform has been demonstrated. Nano-EM is capable of machining nano-features, under both, liquid dielectric (wet nano-EM) and air dielectric (dry nano-EM) media. The objective of this paper is to present a comparative study between the wet and dry nano-EM processes based on process mechanism, machining performance, consistency and dimensional repeatability of these two processes. The comparison of the two processes has been conducted at near field nano-EM, where the gap between the tool electrode and workpiece is 2 nm and the machining is performed at room …

Inducing Neurite Outgrowth By Mechanical Cell Stretch, Suzanne Higgins, Jeong Soon Lee, Ligyeom Ha, Jung Yul Lim

Department of Mechanical and Materials Engineering: Faculty Publications

Establishing extracellular milieus to stimulate neuronal regeneration is a critical need in neuronal tissue engineering. Many studies have used a soluble factor (such as nerve growth factor or retinoic acid [RA]), micropatterned substrate, and electrical stimulation to induce enhanced neurogenesis in neuronal precursor cells. However, little attention has been paid to mechanical stimulation because neuronal cells are not generally recognized as being mechanically functional, a characteristic of mechanoresponsive cells such as osteoblasts, chondrocytes, and muscle cells. In this study, we performed proof-of-concept experiments to demonstrate the potential anabolic effects of mechanical stretch to enhance cellular neurogenesis. We cultured human neuroblastoma …

Systems Biology Of The Functional And Dysfunctional Endothelium, Jennifer Frueh, Nataly Maimari, Takayuki Homma, Sandra M. Bovens, Ryan M. Pedrigi, Leila Towhidi, Rob Krams

Department of Mechanical and Materials Engineering: Faculty Publications

This review provides an overview of the effect of blood flow on endothelial cell (EC) signalling pathways, applying microarray technologies to cultured cells, and in vivo studies of normal and atherosclerotic animals. It is found that in cultured ECs, 5–10% of genes are up- or down-regulated in response to fluid flow, whereas only 3–6% of genes are regulated by varying levels of fluid flow. Of all genes, 90%are regulated by the steady part of fluid flow and 10% by pulsatile components. The associated gene profiles show high variability from experiment to experiment depending on experimental conditions, and importantly, the bioinformatical …

Solution-Processed Nanoparticle Super-Float-Gated Organic Field-Effect Transistor As Un-Cooled Ultraviolet And Infrared Photon Counter, Yongbo Yuan, Qingfeng Dong, Bin Yang, Fawen Guo, Qi Zhang, Ming Han, Jinsong Huang

Department of Mechanical and Materials Engineering: Faculty Publications

High sensitivity photodetectors in ultraviolet (UV) and infrared (IR) range have broad civilian and military applications. Here we report on an un-cooled solution-processed UV-IR photon counter based on modified organic field-effect transistors. This type of UV detectors have light absorbing zinc oxide nanoparticles (NPs) sandwiched between two gate dielectric layers as a floating gate. The photon-generated charges on the floating gate cause high resistance regions in the transistor channel and tune the source-drain output current. This ‘‘super-float-gating’’ mechanism enables very high sensitivity photodetectors with a minimum detectable ultraviolet light intensity of 2.6 photons/µm²s at room temperature as well …