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Articles 76051 - 76080 of 196361

Full-Text Articles in Engineering

How Much Privacy Do We Have Today? A Study Of The Life Of Marc Mezvinsky, Miguel Mares, Salomon Gilles, Brian D. Gobran, Dan Engels Jul 2018

How Much Privacy Do We Have Today? A Study Of The Life Of Marc Mezvinsky, Miguel Mares, Salomon Gilles, Brian D. Gobran, Dan Engels

SMU Data Science Review

In this paper, we present a case study evaluating the level of information available about an individual through public, Internet-accessible sources. Privacy is a basic tenet of democratic society, but technological advances have made access to information and the identification of individuals much easier through Internet-accessible databases and information stores. To determine the potential level of privacy available to an individual in today’s interconnected world, we sought to develop a detailed history of Marc Mezvinsky, a semi-public figure, husband of Chelsea Clinton, and son of two former members of the United States House of Representatives. By utilizing only publicly and …


Fuel Flow Reduction Impact Analysis Of Drag Reducing Film Applied To Aircraft Wings, Damon Resnick, Chris Donlan, Nimish Sakalle, Cody Pinkerman Jul 2018

Fuel Flow Reduction Impact Analysis Of Drag Reducing Film Applied To Aircraft Wings, Damon Resnick, Chris Donlan, Nimish Sakalle, Cody Pinkerman

SMU Data Science Review

In this paper, we present an analysis of flight data in order to determine whether the application of the Edge Aerodynamix Conformal Vortex Generator (CVG), applied to the wings of aircraft, reduces fuel flow during cruising conditions of flight. The CVG is a special treatment and film applied to the wings of an aircraft to protect the wings and reduce the non-laminar flow of air around the wings during flight. It is thought that by reducing the non-laminar flow or vortices around and directly behind the wings that an aircraft will move more smoothly through the air and provide a …


Biomedical Engineering - An Art Or A Science?, Sowmya Anjur Jul 2018

Biomedical Engineering - An Art Or A Science?, Sowmya Anjur

Faculty Publications & Research

Students discussed recent advances in technology and classified them as belonging to science or engineering. Students were introduced to the human heart and its mechanics, after which they brainstormed in groups to build their own life-sized heart models, choosing from the materials provided and demonstrated their working models to each other. Students were encouraged to create "diseases" in their heart models and explain how they would correlate this to "real'life" experiences. Students were also introduced to my newest project, arduino heart rate monitors and asked to suggest creative projects that they could work on in the near future.


Examination Of Factors Influencing Fcg In Legacy Aluminum Alloys, Sarah E. Galyon Dorman, Scott A Fawaz, Justin W Rausch Jul 2018

Examination Of Factors Influencing Fcg In Legacy Aluminum Alloys, Sarah E. Galyon Dorman, Scott A Fawaz, Justin W Rausch

Stress-Assisted Corrosion Damage V

In work sponsored by the Office of Naval Research a corrosion fatigue test method to better replicate real world corrosion conditions using salt film, relative humidity, ozone and UV-light, is being developed [1]. This method is being used to evaluate the effect of atmospheric corrosion conditions in AA7075-T651 with inhibitive coatings including epoxy chromate and three chromate replacement coatings (water and epoxy based rare earth primers and an aluminum rich primer). The corrosion fatigue results are being paired with leaching studies under traditional immersion and atmospheric conditions on the primers to determine how the leaching rates relate to the ability …


Phase Equilibrium Modelling And Implications For P-T Determinations Of Medium-Temperature Uhp Eclogites, North Qaidam Terrane, China, David Hernández‐Uribe, Chris G. Mattinson, Jianxin Zhang Jul 2018

Phase Equilibrium Modelling And Implications For P-T Determinations Of Medium-Temperature Uhp Eclogites, North Qaidam Terrane, China, David Hernández‐Uribe, Chris G. Mattinson, Jianxin Zhang

All Faculty Scholarship for the College of the Sciences

In contrast to low-T eclogites (garnet growth zoning preserved) or high-T eclogites (garnet diffusionally homogenized at peak conditions), medium-temperature eclogites pose additional challenges to P-T determinations due to the partial preservation of garnet zoning. The Dulan area, in the southeastern part of North Qaidam ultrahigh-pressure terrane, exposes minor eclogites hosted by ortho- and paragneisses. Four fresh, medium-temperature eclogites contain the paragenesis Grt+Omp+Rt+Qz/Coe+Ph +/- Ky +/- Zo. In all samples, garnet X-Mg shows little zoning, suggesting diffusional modification, and precludes the use of pyrope+almandine+grossular isopleth intersections to determine a P-T path. However, in one sample, sharp zoning in grossular content suggests …


A Rheometry Method To Assess The Evaporation-Induced Mechanical Strength Development Of Polymer Solutions Used For Membrane Applications, Eduard Caicedo Casso, Jessica L Sargent, Rachel M. Dorin, Ulrich B. Wiesner, William A. Phillip, Bryan M. Boudouris, Kendra Erk Jul 2018

A Rheometry Method To Assess The Evaporation-Induced Mechanical Strength Development Of Polymer Solutions Used For Membrane Applications, Eduard Caicedo Casso, Jessica L Sargent, Rachel M. Dorin, Ulrich B. Wiesner, William A. Phillip, Bryan M. Boudouris, Kendra Erk

School of Materials Engineering Faculty Publications

Rotational and oscillatory shear rheometry were used to quantify the flow behavior under minimal and significant solvent evaporation conditions for polymer solutions used to fabricate isoporous asymmetric membranes by the self-assembly and non-solvent induced phase separation (SNIPS) method. Three different A-B-C triblock terpolymer chemistries of similar molar mass were evaluated: polyisoprene-^-polystyrene-6-poly(4-vinylpyridine) (ISV); polyisoprene-6- polystyrene-6-poly(V,A-dimethylacrylamide) (ISD); and polyisoprene-Z>-polystyrene-h-poly(fer/- butyl methacrylate) (ISB). Solvent evaporation resulted in the formation of a viscoelastic film typical of asymmetric membranes. Solution viscosity and film viscoelasticity were strongly dependent on the chemical structure of the triblock terpolymer molecules. A hierarchical magnitude (ISV>ISB>ISD) was observed …


Dna Identification Of Polyculture, Andrew Schuler Jul 2018

Dna Identification Of Polyculture, Andrew Schuler

Energize New Mexico (NSF EPSCoR Track 1 IV)

DNA sequencing of algae polyculture growing in oilfield produced water. It is dominated by the algae species Parachlorella kessleri and Cyanobacterium aponinum.


V. Dean Adams Retires From Usu’S College Of Engineering, Usu College Of Engineering Jul 2018

V. Dean Adams Retires From Usu’S College Of Engineering, Usu College Of Engineering

College of Engineering News

Students, faculty and staff members at Utah State University extend their heartfelt congratulations and farewell to Dr. V. Dean Adams who last month officially retired from his role as Executive Associate Dean of the College of Engineering.


Transition From Small To Large Cracks In Ti-6al-4v Specimens, Emanuele Vincenzo Arcieri, Sergio Baragetti, Emanuele Borzini Jul 2018

Transition From Small To Large Cracks In Ti-6al-4v Specimens, Emanuele Vincenzo Arcieri, Sergio Baragetti, Emanuele Borzini

Stress-Assisted Corrosion Damage V

Light alloys allow us to have light components with interesting mechanical features. Ti-6Al-4V is a bimodal titanium alloy employed in aerospace, automotive, maritime and biomedical applications. This alloy has also a good corrosion strength which can be reduced by damages on the passivating surface layer. These damages can be due to an inadequate adhesion of the surface layer, variable loads and interactions with aggressive media [1,2].

For these reasons, quasi-static and fatigue tests on Ti-6Al-4V specimens in different inert, aggressive and very aggressive environments were carried out in the past. Air, air + beeswax coating, paraffin oil, 3.5wt.% NaCl-water solution …


Molecular Dynamics Simulation Study On The Possible Factors Affecting Stability Of Ods Steel, M. Mustafa Azeem, Zhongyu Li, Qingyu Wang, Abid Hussian Jul 2018

Molecular Dynamics Simulation Study On The Possible Factors Affecting Stability Of Ods Steel, M. Mustafa Azeem, Zhongyu Li, Qingyu Wang, Abid Hussian

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Oxide-dispersed-strengthened (ODS) steel has excellent mechanical, thermodynamic and radiation resistant properties, which makes it an important candidate material for high-Temperature reactors applications. Radiation stability of oxide is very important to study at the atomic level. In present case molecular dynamics (MD) simulation is used to study stabilities of Y2O3 particles in ODS steel as a function of particle sizes. The size dependence is obvious for particle sizes larger than 2.8 nm. Furthermore, the stabilities depend on charges of Y and O atoms.


Design Of Lattice Structures With Graded Density Fabricated By Additive Manufacturing, Wenjin Tao, Yong Liu, Austin T. Sutton, Krishna C. R. Kolan, Ming-Chuan Leu Jul 2018

Design Of Lattice Structures With Graded Density Fabricated By Additive Manufacturing, Wenjin Tao, Yong Liu, Austin T. Sutton, Krishna C. R. Kolan, Ming-Chuan Leu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Lattice structures fabricated by Additive Manufacturing (AM) processes are promising for many applications, such as lightweight structures and energy absorbers. However, predicting and controlling of their mechanical behaviors is challenging due to the complexity of modeling and the uncertainties exist in the manufacturing process. In this paper, we explore the possibilities enabled by controlling the local densities. A set of lattice structures with different density gradients are designed using an implicit isosurface equation, and they are manufactured by Selective Laser Melting (SLM) process with 304L stainless steel. Finite element analysis and compression test are used to evaluate their mechanical properties. …


U.S. Government Aviation Safety Information Resources, Bert Chapman Jul 2018

U.S. Government Aviation Safety Information Resources, Bert Chapman

Libraries Faculty and Staff Presentations

Presentation covering U.S. Government aviation safety information resources. Topics addressed include U.S. laws,legislation, regulations, court cases, information resources from agencies such as the Federal Aviation Administration, Transportation Security Administration, National Aeronautics and Space Administration, congressional aviation oversight committees and congressional support agencies including the Congressional Budget Office, Congressional Research Service, and Government Accountability Office.


Cyclists' Queue Discharge Characteristics At Signalized Intersections, Kirk Thomas Paulsen Jul 2018

Cyclists' Queue Discharge Characteristics At Signalized Intersections, Kirk Thomas Paulsen

Dissertations and Theses

Wider bike facilities intuitively accommodate a greater number of cyclists in the same amount of time, but specific queue discharge characteristics associated with varying widths and/or types of bike facilities have not been thoroughly documented.

The focus of this research analyzed queues of cyclists at four signalized intersections in Portland, OR with varying widths on the approach and downstream intersection legs. A total of 2,820 cyclists within 630 groups of queued cyclists were observed at five different intersection layouts in Portland, Oregon. The layouts consisted of: a standard bike lane six feet wide connecting bicyclists to a standard bike lane …


Rates Of Cavity Filling By Liquids, Dongjin Seo, Alex M. Schrader, Szu-Ying Chen, Yair Kaufman, Thomas R. Cristiani, Steven H. Page, Peter H. Koenig, Yonas Gizaw, Dong Woog Lee, Jacob N. Israelachvili Jul 2018

Rates Of Cavity Filling By Liquids, Dongjin Seo, Alex M. Schrader, Szu-Ying Chen, Yair Kaufman, Thomas R. Cristiani, Steven H. Page, Peter H. Koenig, Yonas Gizaw, Dong Woog Lee, Jacob N. Israelachvili

Faculty Publications

Understanding the fundamental wetting behavior of liquids on surfaces with pores or cavities provides insights into the wetting phenomena associated with rough or patterned surfaces, such as skin and fabrics, as well as the development of everyday products such as ointments and paints, and industrial applications such as enhanced oil recovery and pitting during chemical mechanical polishing. We have studied, both experimentally and theoretically, the dynamics of the transitions from the unfilled/partially filled (Cassie–Baxter) wetting state to the fully filled (Wenzel) wetting state on intrinsically hydrophilic surfaces (intrinsic water contact angle < 90°, where the Wenzel state is always the thermodynamically favorable state, while a temporary metastable Cassie–Baxter state can also exist) to determine the variables that control the rates of such transitions. We prepared silicon wafers with cylindrical cavities of different geometries and immersed them in bulk water. With bright-field and confocal fluorescence microscopy, we observed the details of, and the rates associated with, water penetration into the cavities from the bulk. We find that unconnected, reentrant cavities (i.e., cavities that open up below the surface) have the slowest cavity-filling rates, while connected or non-reentrant cavities undergo very rapid transitions. Using these unconnected, reentrant cavities, we identified the variables that affect cavity-filling rates: (i) the intrinsic contact angle, (ii) …


Whole Cell Cross-Linking To Discover Host-Microbe Protein Cognate Receptor/Ligand Pairs, Bart C. Weimer, Poyin Chen, Prerak T. Desai, Dong Chen, Jigna Shah Jul 2018

Whole Cell Cross-Linking To Discover Host-Microbe Protein Cognate Receptor/Ligand Pairs, Bart C. Weimer, Poyin Chen, Prerak T. Desai, Dong Chen, Jigna Shah

Biological Engineering Faculty Publications

Bacterial surface ligands mediate interactions with the host cell during association that determines the specific outcome for the host–microbe association. The association begins with receptors on the host cell binding ligands on the microbial cell to form a partnership that initiates responses in both cells. Methods to determine the specific cognate partnerships are lacking. Determining these molecular interactions between the host and microbial surfaces are difficult, yet crucial in defining biologically important events that are triggered during association of the microbiome, and critical in defining the initiating signal from the host membrane that results in pathology or commensal association. In …


Retrieval Of Infotainment System Artifacts From Vehicles Using Ive, Celia J. Whelan, John Sammons, Brian Mcmanus, Terry W. Fenger Jul 2018

Retrieval Of Infotainment System Artifacts From Vehicles Using Ive, Celia J. Whelan, John Sammons, Brian Mcmanus, Terry W. Fenger

Journal of Applied Digital Evidence

The analysis of mobile devices and hard drives has been the focus of the digital forensics world for years, but there is another source of potential evidence not often considered: vehicles. Many of today’s “connected cars” have systems that function like computers, storing information they process including user data from devices synced to the system. There has been little to no research done regarding what types of user artifacts can be found on the system, how long these artifacts remain, whether or not the user can remove those artifacts, and whether certain systems provide more information than others. For this …


Effect Of Cyclic Loading On Hydrogen Diffusion In Low Carbon Steels, Diego Pesenti Bucella, Lorenzi S, Pastore T, Cabrini M. Jul 2018

Effect Of Cyclic Loading On Hydrogen Diffusion In Low Carbon Steels, Diego Pesenti Bucella, Lorenzi S, Pastore T, Cabrini M.

Stress-Assisted Corrosion Damage V

Carbon steels or low-alloyed steels may be affected by damaging phenomena due to Hydrogen Embrittlement (HE), which is a particular form of Environmental Assisted Cracking (EAC). The insurgence of HE depends on the intrinsic susceptibility of the steel, the applied stress, and the concentration of hydrogen inside the metal. It occurs by a mechanism of absorption and subsequent diffusion of atomic hydrogen through the metal lattice.

On steels with a yield strength lower than 700 MPa, HE occurs in the plastic deformation field, in the presence of dynamic loading at slow strain rates or cyclic fatigue loading at very low …


Investigation Of Scc Of High Strength Aluminum Alloys By Means Of Slow Strain Rate Test And Cyclic Anodic Polarization In Combination, Monica Trueba, Guido Russo, Stefano P. Trasatti, Sergio Lorenzi, Marina Cabrini, Antonietta Loconte Jul 2018

Investigation Of Scc Of High Strength Aluminum Alloys By Means Of Slow Strain Rate Test And Cyclic Anodic Polarization In Combination, Monica Trueba, Guido Russo, Stefano P. Trasatti, Sergio Lorenzi, Marina Cabrini, Antonietta Loconte

Stress-Assisted Corrosion Damage V

The stress corrosion cracking (SCC) behavior of high strength 7075-T6 and 2024-T3 Al alloys in NaCl solutions is investigated by means of slow strain rate test (SSRT) and cyclic anodic polarization in combination. Smooth, dog-bone shaped flat tension test specimens, having gage section areas of 40 mm2 and 32 mm2, respectively, and 90 mm of gage length, were machined in the longitudinal (rolling) direction from the commercial wrought sheets (Aviometal Spa). The tensile test was performed at a constant strain rate (ἐ = 10-7, 10-6 or 10-5 s-1) from a pre-load …


Assessment Of Seismic Retrofit Prioritization Methodology For Oregon's Highway Bridges Based On The Vulnerability Of Highway Segments, Selamawit Tesfayesus Mehary Jul 2018

Assessment Of Seismic Retrofit Prioritization Methodology For Oregon's Highway Bridges Based On The Vulnerability Of Highway Segments, Selamawit Tesfayesus Mehary

Dissertations and Theses

Geologists have indicated that the question is not if a catastrophic earthquake will occur in Oregon but when one will occur. Scientists estimate that there is close to 40 percent conditional probability that a Cascadia subduction zone earthquake of magnitude 8.0 or above will strike Oregon in the next 50 years. In addition, the majority of Oregon's bridge inventory was built prior to the current understanding of bridge response and prior to current understanding of the expected earthquake demands. In order to minimize potential bridge damage in the case of an earthquake, one approach is to retrofit seismically deficient bridges. …


Adoption Of An Internet Of Things Framework For Distributed Energy Resource Coordination And Control, Tylor Slay Jul 2018

Adoption Of An Internet Of Things Framework For Distributed Energy Resource Coordination And Control, Tylor Slay

Dissertations and Theses

Increasing penetration of non-dispatchable renewable energy resources and greater peak power demand present growing challenges to Bulk Power System (BPS) reliability and resilience. This research investigates the use of an Internet of Things (IoT) framework for large scale Distributed Energy Resource (DER) aggregation and control to reduce energy imbalance caused by stochastic renewable generation. The aggregator developed for this research is Distributed Energy Resource Aggregation System (DERAS). DERAS comprises two AllJoyn applications written in C++. The first application is the Energy Management System (EMS), which aggregates, emulates, and controls connected DERs. The second application is the Distributed Management System (DMS), …


Advanced Recurrent Network-Based Hybrid Acoustic Models For Low Resource Speech Recognition, Jian Kang, Wei-Qiang Zhang, Wei-Wei Liu, Jia Liu, Michael T. Johnson Jul 2018

Advanced Recurrent Network-Based Hybrid Acoustic Models For Low Resource Speech Recognition, Jian Kang, Wei-Qiang Zhang, Wei-Wei Liu, Jia Liu, Michael T. Johnson

Electrical and Computer Engineering Faculty Publications

Recurrent neural networks (RNNs) have shown an ability to model temporal dependencies. However, the problem of exploding or vanishing gradients has limited their application. In recent years, long short-term memory RNNs (LSTM RNNs) have been proposed to solve this problem and have achieved excellent results. Bidirectional LSTM (BLSTM), which uses both preceding and following context, has shown particularly good performance. However, the computational requirements of BLSTM approaches are quite heavy, even when implemented efficiently with GPU-based high performance computers. In addition, because the output of LSTM units is bounded, there is often still a vanishing gradient issue over multiple layers. …


An Optimal Airline Revenue Management Seat Pricing Plan Model, Constantine M. Koursaris, James W. Marion Jr. Jul 2018

An Optimal Airline Revenue Management Seat Pricing Plan Model, Constantine M. Koursaris, James W. Marion Jr.

International Journal of Aviation, Aeronautics, and Aerospace

The goal of an airline is to sell tickets at the highest fare possible, thus yielding maximum profit for the stakeholders. As airline seat pricing is divided into different fare classes, a revenue management system is created and maintained to identify opportunity costs where the airline may sell an optimum number of available seats in both discounted fare and full fare classes. Ideally, under perfect conditions, the airline will sell all available seats at full capacity for each leg of a trip. Under non-ideal conditions for the airline, not all available seats may sell at either full fare or discounted …


A Comparative Study Of Signal Processing Methods For Fetal Phonocardiography Analysis, Venkata Akshay Bhargav Krishna Vadali Jul 2018

A Comparative Study Of Signal Processing Methods For Fetal Phonocardiography Analysis, Venkata Akshay Bhargav Krishna Vadali

USF Tampa Graduate Theses and Dissertations

More than one million fetal deaths occur in the United States every year [1]. Monitoring the long-term heart rate variability provides a great amount of information about the fetal health condition which requires continuous monitoring of the fetal heart rate. All the existing technologies have either complex instrumentation or need a trained professional at all times or both. The existing technologies are proven to be impractical for continuous monitoring [2]. Hence, there is an increased interest towards noninvasive, continuous monitoring, and less expensive technologies like fetal phonocardiography.

Fetal Phonocardiography (FPCG) signal is obtained by placing an acoustic transducer on the …


Data-Driven Development Of A Roadside Safety Marketing Campaign For Tree Removal – Phase I, Cody S. Stolle, Thomas Ammon, Chris M. Vargas, Ronald K. Faller, Karla A. Lechtenberg, Erin L. Urbank Jul 2018

Data-Driven Development Of A Roadside Safety Marketing Campaign For Tree Removal – Phase I, Cody S. Stolle, Thomas Ammon, Chris M. Vargas, Ronald K. Faller, Karla A. Lechtenberg, Erin L. Urbank

Nebraska Department of Transportation: Research Reports

Since the 1970s, tree crashes have been one of the most common and deadly fixed-object fatal crash types, resulting in more than 3,000 fatal crashes and 3,500 fatalities each year. While fatal tree crashes could be prevented by removing trees adjacent to the roadway, an extensive national tree removal project would be unnecessary, cost-prohibitive, and would experience significant political resistance.

The Midwest Pooled Fund Program jointly funded a research study to develop marketing methods and approaches which would focus on tree removal, replacement, or relocation in the most critical areas. Researchers conducted an extensive background investigation into tree crashes, other …


The Perceived Value Of Frequent Flyer Program Benefits Among Australian Travelers, Yi Gao, Madeline Carrigg, Robert Lewinski, Danielle Polderman, Paul Tkalcevic Jul 2018

The Perceived Value Of Frequent Flyer Program Benefits Among Australian Travelers, Yi Gao, Madeline Carrigg, Robert Lewinski, Danielle Polderman, Paul Tkalcevic

International Journal of Aviation, Aeronautics, and Aerospace

Understanding the perceived value of frequent flyer program benefits is crucial for commercial operations of airlines. This study aimed to investigate if travelers value various benefits provided by airlines and if such valuation correlates with certain characteristics of travelers. Through a scenario-based questionnaire it was confirmed that travelers do value extra and premium benefits offered by airlines, and such valuation increases along with the distance of route. It was also been found that top-tier members were willing to make a much higher offer for the same benefits on long-haul international route than members of lower status, but such difference in …


Tunable Plasmonic Resonances In Highly Porous Nano-Bamboo Si-Au Superlattice-Type Thin Films, Ufuk Kılıç, Alyssa Mock, René Feder, Derek Sekora, Matthew J. Hilfiker, Rafal Korlacki, Eva Schubert, Christos Argyropoulos, Mathias Schubert Jul 2018

Tunable Plasmonic Resonances In Highly Porous Nano-Bamboo Si-Au Superlattice-Type Thin Films, Ufuk Kılıç, Alyssa Mock, René Feder, Derek Sekora, Matthew J. Hilfiker, Rafal Korlacki, Eva Schubert, Christos Argyropoulos, Mathias Schubert

Department of Electrical and Computer Engineering: Faculty Publications

We report on fabrication of spatially-coherent columnar plasmonic nanostructure superlattice-type thin films with high porosity and strong optical anisotropy using glancing angle deposition. Subsequent and repeated depositions of silicon and gold lead to nanometer-dimension subcolumns with controlled lengths. The superlattice-type columns resemble bamboo structures where smaller column sections of gold form junctions sandwiched between larger silicon column sections (“nano-bamboo”). We perform generalized spectroscopic ellipsometry measurements and finite element method computations to elucidate the strongly anisotropic optical properties of the highly-porous nano-bamboo structures. The occurrence of a strongly localized plasmonic mode with displacement pattern reminiscent of a dark quadrupole mode is …


Investigation Of The Acoustic Response Of A Confined Mesoscopic Water Film Utilizing A Combined Atomic Force Microscope And Shear Force Microscope Technique, Monte Allen Kozell Jul 2018

Investigation Of The Acoustic Response Of A Confined Mesoscopic Water Film Utilizing A Combined Atomic Force Microscope And Shear Force Microscope Technique, Monte Allen Kozell

Dissertations and Theses

An atomic force microscopy beam-like cantilever is combined with an electrical tuning fork to form a shear force probe that is capable of generating an acoustic response from the mesoscopic water layer under ambient conditions while simultaneously monitoring force applied in the normal direction and the electrical response of the tuning fork shear force probe. Two shear force probes were designed and fabricated. A gallium ion beam was used to deposit carbon as a probe material. The carbon probe material was characterized using energy dispersive x-ray spectroscopy and scanning transmission electron microscopy. The probes were experimentally validated by demonstrating the …


Relative Navigation: A Keyframe-Based Approach For Observable Gps-Degraded Navigation, David O. Wheeler, Daniel P. Koch, James S. Jackson, Timothy W. Mclain, Randal W. Beard Jul 2018

Relative Navigation: A Keyframe-Based Approach For Observable Gps-Degraded Navigation, David O. Wheeler, Daniel P. Koch, James S. Jackson, Timothy W. Mclain, Randal W. Beard

Faculty Publications

State estimation for micro air vehicles (MAVs) often depends heavily on reliable global measurements such as GPS. When global measurements are unavailable, additional sensors, such as cameras or laser scanners, are commonly used to provide measurements of the MAV’s translation and rotation relative to a previously observed keyframe image or scan. With the use of only relative sensors, however, the global position and heading of the vehicle are unobservable and cannot be reliably reconstructed. Many existing approaches work with respect to a global reference frame, resulting in a loss of state observability. This article highlights that unobservability leads to inconsistency …


Short Crack Tolerance Under Eac Conditions, Jtp Castro, Rv Landin, In Viçosa, Gr Altoé, Rrc Saúde Jul 2018

Short Crack Tolerance Under Eac Conditions, Jtp Castro, Rv Landin, In Viçosa, Gr Altoé, Rrc Saúde

Stress-Assisted Corrosion Damage V

Notch sensitivity effects under environmentally-assisted cracking (EAC) conditions have been recently quantified considering the tolerance to short cracks that may start at their tips and become non-propagating after growing for a while, a behavior that depends on the stress gradients ahead of the notch tips and on the basic material resistances to crack initiation (SEAC) and propagation (KIEAC) inside an aggressive medium under static loadings. Such properties are time-independent, so they can be directly compared with the notch gradient-affected stress intensity factors of the short cracks that depart from notch tips. This model can provide a …


In Situ Strain And Damage Monitoring Of Gfrp Laminates Incorporating Carbon Nanofibers Under Tension, Yanlei Wang, Yongshuai Wang, Baoguo Han, Baolin Wan, Gaochuang Cai, Ruijuan Chang Jul 2018

In Situ Strain And Damage Monitoring Of Gfrp Laminates Incorporating Carbon Nanofibers Under Tension, Yanlei Wang, Yongshuai Wang, Baoguo Han, Baolin Wan, Gaochuang Cai, Ruijuan Chang

Civil and Environmental Engineering Faculty Research and Publications

In this study, conductive carbon nanofibers (CNFs) were dispersed into epoxy resin and then infused into glass fiber fabric to fabricate CNF/glass fiber-reinforced polymer (GFRP) laminates. The electrical resistance and strain of CNF/GFRP laminates were measured simultaneously during tensile loadings to investigate the in situ strain and damage monitoring capability of CNF/GFRP laminates. The damage evolution and conduction mechanisms of the laminates were also presented. The results indicated that the percolation threshold of CNFs content for CNF/GFRP laminates was 0.86 wt % based on a typical power law. The resistance response during monotonic tensile loading could be classified into three …