169 research outputs found
The Benefits of Being Economics Professor A (and not Z)
No full textAlphabetic name ordering on multi-authored academic papers, which is the convention in the economics discipline and various other disciplines, is to the advantage of people whose last name initials are placed early in the alphabet. As it turns out, Professor A, who has been a first author more often than Professor Z, will have published more articles and experienced afaster growth rate over the course of her career as a result of reputation and visibility. Moreover, authors know that name ordering matters and indeed take ordering seriously: Several characteristics of an author group composition determine the decision to deviate from the default alphabetic name order to a significant extent.performance measurement, incentives, economists, name ordering
Electrical Stimulation of Rat Primary Motor Cortex for Neurorehabilitation and Neuroprosthetic Applications.
No full textCortical electrical stimulation (CES) has been used extensively in experimental neuroscience to modulate neuronal or behavioral activity, which has led this technique to be considered in neurorehabilitation. Because the cortex and the surrounding anatomy have irregular geometries as well as inhomogeneous and anisotropic electrical properties, the mechanisms by which CES has therapeutic effects are poorly understood. Therapeutic effects of CES can be improved by optimizing the stimulation parameters for targeted brain regions.
In this dissertation, the effects of CES pulse polarity on neural signals such as unit activity (spikes), local field potentials (LFP), and electrocorticograms (ECoG) recorded from rat primary motor cortex were investigated. The results showed that units located in lower cortical layers are preferentially excited by anodic stimulation, while cathodic stimulation excites those located in upper cortical layers. These opposing effects were also frequency- and amplitude-dependent. Time-frequency analysis of LFPs showed high correlation of gamma (30-120Hz) power with unit activity in corresponding layers. On the other hand, high gamma (60-120Hz) power of ECoG signals only showed high correlation with the unit activity in lower layers. Time-frequency correlations, which were found between LFPs, ECoGs and unit activity were also frequency- and amplitude-dependent. In addition the intracortical microstimulation study showed that lower motor thresholds can be obtained by anodic stimulation in upper layers of motor cortex compared to cathodic and vice versa in lower layers (V/VI). The data demonstrates that the poststimulus effects in neural activity after manipulation of CES parameters changes according to the location (depth) of the recorded neural activity in motor cortex. The signature of the neural activity observed in LFP and ECoG signals provides a better understanding of the effects of stimulation on the affected network and has a promising potential to be used in closed-loop control stimulation systems. These results demonstrate that the neurorehabilitation and neuroprosthetic applications of CES can be further improved by optimizing CES parameters.PhDBiomedical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/86570/1/azadehy_1.pd
Isolated intrasplenic vascular calcifications in a child with type 1 diabetes mellitus‐‐‐A case report
No full textImproving the Imaging Speed of an Atomic Force Microscope: A simulation study
No full textThe Atomic Force Microscope is a type of high-resolution Scanning Probe Microscope where the image resolution has been demonstrated to be 3 orders of magnitude better than the optical diffraction limit. Directly observing individual protein molecules in action at high spatio-temporal resolutions has long been a holy grail for biological science. High-Speed Atomic Force Microscopy allows us to directly visualize the structural dynamics and dynamic processes of biological molecules in physiological solutions, at sub-second to sub-100-ms temporal resolutions, without disturbing their function. This has been demonstrated, where dynamically acting molecules such as Myosin V walking on an Actin filament and Bacteriorhodopsin in response to light were successfully visualized. Despite this remarkable progress, there are still many biomolecules whose structure is still not elucidated due limitations in scanning speed.The goal of this thesis is to investigate control techniques namely Q-Control and Direct Tip-sample Force estimation in a simulation environment developed over the course of this thesis to see if they can be used to improve the imaging speed of an AFM. A next step towards implementing these controllers on aField-Programmable Gate Array (FPGA) is also made, where a Fixed-Point implementationof the controller is realized and simulated in a FPGA simulation environmentMechanical Engineering | Systems and Contro
Problem Sets for Aerospace Structures
No full textThis collection of interactive problems and solutions includes over twenty-five collections of 3-5 problems each on topics relevant to undergraduate-level aerospace structures such as: load factors, strain, stress, stress transformation and principal stresses, material properties, composites, equations of equilibrium, Airy stress function, thermoelasticity, failure theories, elastic-plastic analysis, fracture, beam bending, principal of minimum total potential energy, finite element method for beams, plate bending, buckling, structural dynamics, and aeroelasticity.
Purpose
The problem sets were developed to help faculty provide regular formative assessments to the students without any corresponding grading burden (for the faculty or TA). The assessments can be given twice a week in a typical class and can help the students get feedback on a regular basis. Problem sets supplement the open textbook, Aerospace Structures by Eric Raymond Johnson (2022) https://doi.org/10.21061/AerospaceStructures.
Author and license information
The problem sets were developed by Mayuresh Patil, former Associate Department Chair, Kevin T. Crofton Department of Aerospace and Oceanic Engineering at Virginia Tech, and currently Professor of Practice at Daniel Guggenheim School of Aerospace Engineering at Georgia Tech.
Problem sets are ©2021 Mayuresh Patil and released under a Creative Commons NonCommercial ShareAlike 4.0 (CC BY NC-SA) license. License terms are available at https://creativecommons.org/licenses/by-nc-sa/4.0.
Suggested citation
Patil, Mayuresh. (2021) Problem Sets for Aerospace Structures. CC BY-NC-SA. Retrieved from http://hdl.handle.net/10919/104169.
Technical notes regarding use of the problem sets
Each of the 25+ problem sets were built in Canvas “legacy quizzes” and exported into the IMS QTI 1.2 format.
Open access to the problem sets
- Problem sets are available for free public view in Canvas Commons. View the list of direct links provided below, download the file titled "Problem_set_URLs_for_Canvas_Commons.txt (2.863Kb)" from this page, or search for “Aerospace Structures” at https://lor.instructure.com. A Canvas account is not required to view items designated as “public” in Canvas Commons.
- Users logged into a Canvas account may import these directly to an existing course or download them in IMS QTI 1.2 format for use in a different IMS QTI compatible system such as Blackboard, D2L, or other IMS QTI-compliant systems.
- Users without a Canvas account have the option to create a free canvas account at: https://canvas.instructure.com/register_from_website, which will allow them to export / download them.
- IMS QTI 1.2 formatted downloads of problem sets are also available as Zip files without a login on the left side of this page. They were exported using open source 7zip software.
Please note that we are unable to provide additional file types, support for uploading, or assistance with reformatting files. Please contact your local learning management system (LMS) manager for additional support.
Help us!
If you are an instructor using, reviewing, adopting, or adapting questions from the problem set we would love to know! Please help us understand your use by filling out this form.
Acknowledgments
This project was made possible in part by funding of the Virtual Library of Virginia and assistance from the Open Education Initiative of the University Libraries at Virginia Tech.
Author: Mayuresh Patil
Project Manager: Anita Walz
Direct links to problem sets in the Canvas Commons system
- Airy Stress Function (Part I)
https://lor.instructure.com/resources/bc7f1eac158e4ec69d8542348492cbe7?shared
- Airy Stress Function (Part II):
https://lor.instructure.com/resources/cadcd3b91117444a8539e6068fae4860?shared
- Beam Buckling:
https://lor.instructure.com/resources/dbd9e74cbe4c474483aed9ba3d46cebd?shared
- Beam Buckling using PMTPE:
https://lor.instructure.com/resources/09051d82e6f145d292d43f2192a08dce?shared
- Buckling (Discrete Systems):
https://lor.instructure.com/resources/1f444c42b32c40899ebbf183cc43ad80?shared
- Beam Analysis using PMTPE:
https://lor.instructure.com/resources/d1cc9160c39b48f493a59c6104d5d33a?shared
- Composites:
https://lor.instructure.com/resources/4b776606c2e9494f8464b775815878c3?shared
- Constitutive Law:
https://lor.instructure.com/resources/e55059203a5d45f29a9f1468f1a48b9d?shared
- Elastic-Plastic Analysis:
https://lor.instructure.com/resources/7b7f2fcf64bd44d880695ee33bda08fd?shared
- Equilibrium:
https://lor.instructure.com/resources/52995ce999ad4894b8e2b312bba7bfc6?shared
- Failure Theories:
https://lor.instructure.com/resources/007a7ae0772644e387f2473ba5a1ed46?shared
- Fracture:
https://lor.instructure.com/resources/f7c46457a70e4a21a2b5b3bf819fc804?shared
- Load Factors:
https://lor.instructure.com/resources/b1d1974fe78c46ba8f4c5c6c733a1737?shared
- Material Properties:
https://lor.instructure.com/resources/75def72391b945c3bce8c73a5eb6c052?shared
- Plate Bending:
https://lor.instructure.com/resources/285f2faccc8a4ce5a45d2256e8106066?shared
- Plate Buckling using PMTPE:
https://lor.instructure.com/resources/49937783dff542e1b4dc80fa979a4d87?shared
- PMTPE (Discrete Systems):
https://lor.instructure.com/resources/3b9e350fa6004c18aa2568b16caddfc8?shared
- Strain:
https://lor.instructure.com/resources/934505d71f124d249067be1f5b7eb753?shared
- Stress:
https://lor.instructure.com/resources/90190ea55ae641459661c1f199549948?shared
- Thermoelasticity:
https://lor.instructure.com/resources/d0a90b895c2545768b3df07c0210ffea?shared
- V-n diagram:
https://lor.instructure.com/resources/32617ae1ff3344258354b4385693f4aa?shared
- Plate Buckling:
https://lor.instructure.com/resources/1264f807f84f44808e03e00be51e5c49?shared
- Plate with a Hole:
https://lor.instructure.com/resources/672eca566a814e16b052757004f68963?shared
- Polar Coordinates:
https://lor.instructure.com/resources/2b20db974faa44309430866eae247a9e?shared
- Principle/Maximum Stresses:
https://lor.instructure.com/resources/df7c8e088ccb4a9991753f87b15c99ff?shared
- Stress/Strain Transformation:
https://lor.instructure.com/resources/4a11d3349e8e4443b607915656279cd3?sharedVIVA (Virtual Library of Virginia
Low temperature silicon nitride deposited by Cat-CVD for deep sub-micron metal–oxide–semiconductor devices
No full textSilicon nitride as a gate dielectric can improve the performance of ULSI CMOS devices by decreasing the gate leakage currents. In this paper we report a a-SiN:H gate dielectric fabricated using Cat-CVD at a relatively low substrate temperature of ∼250°C, using silane and ammonia as the source gases. The films were deposited at various gas pressures, (NH3/SiH4) flow rate ratios and at different filament temperatures (TF). The deposition parameters, i.e. total gas pressure and gas composition (silane+ammonia) were optimized to deposit insulating and transparent films with high breakdown strength. The structural properties of these films were studied by Fourier transform infrared (FTIR) spectroscopy and ultraviolet-visible (UV-vis) spectroscopy. Films with bandgap as high as 5.5 eV were obtained. The optimized conditions were used to deposit ultrathin films of the order of 8 nm thickness for deep-submicron CMOS technology. Electrical properties such as C–V and I–V measurements were studied on metal–nitride–semiconductor (MNS) capacitor structures. These characterization results on MNS capacitors show breakdown fields of the order of 10 MV cm−1 and good interface properties
Steady state and time resolved methods of fluorescence quenching of heterocyclic compound in dioxane solvent using linear S-V plots
No full text
Algorithm for Solving Tri-diagonal Finite Volume Discretized Linear Systems
No full textIn this paper we present efficient computational algorithms for solving finite volume discretized tri-diagonal linear systems. The implementation of the algorithm for steady state finite volume structured grids linear system using MS Excel is presented. An example is given in order to illustrate the algorithms
Algorithm for Solving Tri-diagonal Finite Volume Discretized Linear Systems
No full textAbstract In this paper we present efficient computational algorithms for solving finite volume discretized tri-diagonal linear systems. The implementation of the algorithm for steady state finite volume structured grids linear system using MS Excel is presented. An example is given in order to illustrate the algorithms
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