Pressurized Metal Bellows Shock Absorber For Space Applications.,
2015
University of Central Florida
Pressurized Metal Bellows Shock Absorber For Space Applications., John Trautwein
Electronic Theses and Dissertations
Numerous spacecraft designs exist for exploring the surfaces of planetary bodies and each have their own advantages and disadvantages. All successful landings have been made by stationary landers or wheeled rovers that rely on one-time use mechanisms, such as crushable aluminum honeycomb shock absorbers or inflatable airbags, to reduce shock loading to the spacecraft during landing. The stationary lander is the simplest type of lander, but can only take data from one location. Wheeled rovers add complexity in exchange for mobility to explore different locations. Rovers are limited by the terrain they can traverse; rovers becoming stuck have ended missions. …
Combustion Kinetics Of Advanced Biofuels,
2015
University of Central Florida
Combustion Kinetics Of Advanced Biofuels, Ghazal Barari
Electronic Theses and Dissertations
Use of biofuels, especially in automotive applications, is a growing trend due to their potential to lower greenhouse gas emissions from combustion. Ketones are a class of biofuel candidates which are produced from cellulose. However, ketones received rather scarce attention from the combustion community compared to other classes such as, alcohols, esters, and ethers. There is little knowledge on their combustion performance and pollutant generation. Hence their combustion chemistry needs to be investigated in detail. Diisopropyl ketone (DIPK) is a promising biofuel candidate, which is produced using endophytic fungal conversion. A detailed understanding of the combustion kinetics of the oxidation …
Assessment Of The Wear Effects Of Alumina-Nanofluids On Heat-Exchanger Materials,
2015
Georgia Southern University
Assessment Of The Wear Effects Of Alumina-Nanofluids On Heat-Exchanger Materials, Fnu Aktaruzzaman
Electronic Theses and Dissertations
Nanofluids are nano-size-powder suspensions in liquids that are mainly studied for their abnormal thermal transport properties, and hence as enhanced alternatives to ordinary cooling fluids. The tribological effects of nanofluids are, however, largely unknown, in particular their likely wear and/or erosion effects, because of their interaction with cooling-system (heat-exchanger) materials. The thesis presents research to establish methodologies for testing and evaluating surface-change by nanofluid impact. The work is presented on development of novel test rigs and testing methodologies, and on the use of typical surface analysis tools for assessment of wear and erosion that may be produced by nanofluids; prediction …
Design And Implementation Of An Interactive Animatronic System For Guest Response Analysis,
2015
Georgia Southern University
Design And Implementation Of An Interactive Animatronic System For Guest Response Analysis, Brian Burns
Electronic Theses and Dissertations
In theme park based entertainment applications, there is a need for interactive, autonomous animatronic systems to create engaging and compelling experiences for the guests. The animatronic figures must identify the guests and recognize their status in dynamic interactions for enhanced acceptance and effectiveness as socially interactive agents, in the general framework of human-robot interactions. The design and implementation of an interactive, autonomous animatronic system in form of a tabletop dragon and the comparisons of guest responses in its passive and interactive modes are presented in this work. The dragon capabilities include a four degrees-of-freedom head, moving wings, tail, jaw, blinking …
Networked Heterogeneous Systems In A Ros-Enabled Cloud Environment,
2015
Georgia Southern University
Networked Heterogeneous Systems In A Ros-Enabled Cloud Environment, Christopher Reid
Electronic Theses and Dissertations
It is important in the development of cloud robotics that the challenges presented by transferring computational loads to networked resources are properly addressed. The challenges include network latency, data integrity, security, and privacy. The objective of the present work is to investigate the issues of latency and data integrity in a representative cloud robotics environment. The present work involves setting up a cloud robotics network in an open-source Robot Operating System (ROS) framework and carrying out investigations on the levels of latency and reduction in data integrity as utilization of the network increases. In this study, a virtual datacenter has …
Development And Operation Of A Mobile Test Facility For Education,
2015
Michigan Technological University
Development And Operation Of A Mobile Test Facility For Education, Christopher Davis
Dissertations, Master's Theses and Master's Reports
The automotive industry saw a large shift towards vehicle electrification after the turn of the century. It became necessary to ensure that new and existing engineers were qualified to design and calibrate these new systems. To ensure this training, Michigan Tech received a grant to develop a curriculum based around vehicle electrification. As part of this agenda, the Michigan Tech Mobile Laboratory was developed to provide hands-on training for professional engineers and technicians in hybrid electric vehicles and vehicle electrification. The Mobile Lab has since then increased the scope of the delivered curriculum to include other automotive areas and even …
Combustion And Pollutant Characteristics Of Ic Engines Fueled With Hydrogen And Diesel/Hydrogen Mixtures Using 3d Computations With Detailed Chemical Kinetics,
2015
Missouri University of Science and Technology
Combustion And Pollutant Characteristics Of Ic Engines Fueled With Hydrogen And Diesel/Hydrogen Mixtures Using 3d Computations With Detailed Chemical Kinetics, Hassan A. Khairallah
Doctoral Dissertations
In order to develop design guidelines for optimum operations of internal combustion engines fueled with alternative fuels, a comprehensive understanding combustion behavior and the pollutant formation inside the cylinder are needed. The first part of this thesis aimed to numerically study the engine performance and in-cylinder pollutant formation in a spark ignition engine fueled with hydrogen. Advanced simulations were performed using multi- dimensional software AVL FIRE coupled with CHEMKIN. The detailed chemical reactions with 29 steps of hydrogen oxidation with additional nitrogen oxidation reactions were also employed. Formation rates of nitrogen oxides (NOx) within the engine were accurately predicted using …
Operating Principles, Common Questions, And Performance Data For An Atmospheric Driven Atmos Clock,
2015
Clemson University
Operating Principles, Common Questions, And Performance Data For An Atmospheric Driven Atmos Clock, David Moline, John Wagner
Publications
The elegance of the Atmos clock and the curiosity of mankind in self-operational mechanical systems have propelled this time device into our collective desire for more knowledge. The search for a self-winding time piece, based on normal atmospheric fluctuations, was pursued for centuries by horologists with the well-known clock proposed by J. L. Reutter and commercialized by Jaeger LeCoultre. This clock has generated numerous discussions throughout the years as noted in past Bulletin articles and other correspondences within the time keeping community. In this paper, the operating principles of the Atmos clock will be reviewed using fundamental science and engineering …
Voigt, Reuss, Hill, And Self-Consistent Techniques For Modeling Ultrasonic Scattering,
2015
University of Nebraska-Lincoln
Voigt, Reuss, Hill, And Self-Consistent Techniques For Modeling Ultrasonic Scattering, Christopher M. Kube, Joseph A. Turner
Department of Mechanical and Materials Engineering: Faculty Publications
An elastic wave propagating in a metal loses a portion of its energy from scattering caused by acoustic impedance differences existing at the boundaries of anisotropic grains. Theoretical scattering models capture this phenomena by assuming the incoming wave is described by an average elastic moduli tensorC0ijkl (x) that is perturbed by a grain with elasticityCijkl (x ') where the scattering event occurs when x = x’. Previous models have assumed that C0ijkl (x) is the Voigt average of the singlecrystal elastic moduli tensor. However, this assumption …
Acoustic Nonlinearity Parameters For Transversely Isotropic
Polycrystalline Materials,
2015
University of Nebraska-Lincoln
Acoustic Nonlinearity Parameters For Transversely Isotropic Polycrystalline Materials, Christopher M. Kube, Joseph A. Turner
Department of Mechanical and Materials Engineering: Faculty Publications
This article considers polycrystalline materials with macroscopic elastic anisotropy and the effect of the anisotropy on the quadratic nonlinearity parameter used to describe second harmonic generation in solids. The polycrystal is assumed to have transversely isotropic elastic symmetry, which leads to a directional dependence of the nonlinearity parameters. Additionally, the anisotropy leads to second harmonic generation from an input shear wave. Estimates of the longitudinal and shear wave nonlinearity parameters are given as a function of single-crystal elastic constants, macroscopic anisotropy constants, and propagation direction. An inverse model is presented that relates measured nonlinearity parameters to the macroscopic anisotropy constants. …
Acoustic Attenuation Coefficients For Polycrystalline Materials Containing Crystallites Of Any Symmetry Class,
2015
University of Nebraska-Lincoln
Acoustic Attenuation Coefficients For Polycrystalline Materials Containing Crystallites Of Any Symmetry Class, Christopher M. Kube, Joesph A. Turner
Department of Mechanical and Materials Engineering: Faculty Publications
This letter provides a theoretical extension to the elastic properties of polycrystals in order to describe elastic wave scattering from grain boundaries. The extension allows the longitudinal and shear attenuation coefficients for scattering to be derived and is valid for polycrystals containing crystallites of any symmetry class. Attenuation curves are given for polycrystalline SiO2, ZrO2, and SnF2, which contain monoclinic crystallites. This work will allow ultrasonic techniques to be applied to new classes of materials containing nontrivial microstructures.
Interfacial Electronic Structure At The Ch3nh3pbi3/Moox Interface,
2015
Central South University
Interfacial Electronic Structure At The Ch3nh3pbi3/Moox Interface, Peng Liu, Xiaoliang Liu, Lu Lyu, Haipeng Xie, Hong Zhang, Dongmei Niu, Han Huang, Cheng Bi, Zhengguo Xiao, Jinsong Huang, Yongli Gao
Department of Mechanical and Materials Engineering: Faculty Publications
Interfacial electronic properties of the CH3NH3PbI3 (MAPbI3)/MoOx interface are investigated using ultraviolet photoemission spectroscopy and X-ray photoemission spectroscopy. It is found that the pristine MAPbI3 film coated onto the substrate of poly (3,4-ethylenedioxythiophene) poly(styrenesulfonate)/indium tin oxide by two-step method behaves as an n-type semiconductor, with a band gap of ~1.7 eV and a valence band edge of 1.40 eV below the Fermi energy (EF). With the MoOx deposition of 64A ° upon MAPbI3, the energy levels of MAPbI3 shift toward higher binding energy by 0.25 eV due to electron transfer …
Erratum: “The Operation Mechanism Of Poly (9,9-Dioctylfluorenyl-2,7-Diyl) Dots In High Efficiency Polymer Solar Cells” [Appl. Phys. Lett. 106, 193904 (2015)],
2015
Jilin University
Erratum: “The Operation Mechanism Of Poly (9,9-Dioctylfluorenyl-2,7-Diyl) Dots In High Efficiency Polymer Solar Cells” [Appl. Phys. Lett. 106, 193904 (2015)], Chunyu Liu, Yeyuan He, Xinyuan Zhang, Zhiqi Li, Jinfeng Li, Liang Shen, Zhihui Zhang, Wenbin Guo, Shengping Ruan
Department of Mechanical and Materials Engineering: Faculty Publications
We have noticed an error in Fig. 7 of the original article. Figs. 7(a) and 7(b) should be exchanged and the revised figure is shown below. We apologize for this error.1
The Operation Mechanism Of Poly(9,9-Dioctylfluorenyl-2,7-Diyl) Dots In High Efficiency Polymer Solar Cells,
2015
Jilin University
The Operation Mechanism Of Poly(9,9-Dioctylfluorenyl-2,7-Diyl) Dots In High Efficiency Polymer Solar Cells, Chunyu Liu, Yeyuan He, Xinyuan Zhang, Zhiqi Li, Liang Shen, Zhihui Zhang, Wenbin Guo, Shengping Ruan
Department of Mechanical and Materials Engineering: Faculty Publications
The highly efficient polymer solar cells were realized by doping poly(9,9-dioctylfluorenyl-2,7-diyl) (PFO) dots into active layer. The dependence of doping amount on devices performance was investigated and a high efficiency of 7.15% was obtained at an optimal concentration, accounting for a 22.4% enhancement. The incorporation of PFO dots (Pdots) is conducted to the improvement of Jsc and fill factor mainly due to the enhancement of light absorption and charge transport property. Pdots blended in active layer provides an interface for charge transfer and enables the formation of percolation pathways for electron transport. The introduction of Pdots was proven an effective …
Surface Analytical Investigation On Organometal Triiodide Perovskite,
2015
University of Rochester
Surface Analytical Investigation On Organometal Triiodide Perovskite, Chengong Wang, Xiaoliang Liu, Congcong Wang, Zhengguo Xiao, Cheng Bi, Yuchuan Shao, Jinsong Huang, Yongli Gao
Department of Mechanical and Materials Engineering: Faculty Publications
In a little over a year, there has been an unexpected breakthrough and rapid evolution of highly efficient solid-state hybrid solar cells based on organometal trihalide perovskite materials. This technology has the potential to produce solar cells with the very highest efficiencies while retaining the very lowest cost. The authors have measured the electronic density of states of CH3NH3PbI3 using ultraviolet photoemission spectroscopy (UPS), inverse photoemission spectroscopy (IPES), and x-ray photoemission spectroscopy (XPS). The valence band maximum and conduction band minimum positions are obtained from the UPS and IPES spectra, respectively, by linear extrapolation of …
Phase Transformation And Magnetic Properties Of Rapidly Solidified Mn-Al-C Alloys Modified With Zr,
2015
University of Nebraska–Lincoln
Phase Transformation And Magnetic Properties Of Rapidly Solidified Mn-Al-C Alloys Modified With Zr, Yunlong Geng, Micheal J. Lucis, Pamela Rasmussen, Jeffrey E. Shield
Department of Mechanical and Materials Engineering: Faculty Publications
Mn54-xAl43C3Zrx (x=1, 3) alloys were prepared by rapid solidification followed by heat treatment to produce the ferromagnetic s phase. The substitution of Zr for Mn in the structure resulted in an increase of the saturation magnetization (Ms) compared to that of Mn54-xAl43C3. While the highest Ms (12861 emu/g) was obtained in Mn54-xAl43C3Zr1, the coercivity was also improved to 1.62 kOe, compared to 1.25 kOe for Mn54-xAl43C3. To further improve the coercivity through grain …
Extracting Continuum-Like Deformation And Stress From
Molecular Dynamics Simulations,
2015
University of Oxford
Extracting Continuum-Like Deformation And Stress From Molecular Dynamics Simulations, Lili Zhang, John Jasa, George Gazonas, Antoine Jerusalem, Mehrdad Negahban
Department of Mechanical and Materials Engineering: Faculty Publications
We present methods that use results from molecular dynamics (MD) simulations to construct continuum parameters, such as deformation gradient and Cauchy stress, from all or any part of an MD system. These parameters are based on the idea of minimizing the difference between MD measures for deformation and traction and their continuum counterparts. The procedures should be applicable to non-equilibrium and inhomogeneous systems, and to any part of a system, such as a polymer chain. The resulting procedures provide methods to obtain first and higher order deformation gradients associated with any subset of the MD system, and associated expressions for …
Evaluation Of Peritoneal Microbubble Oxygenation
Therapy In A Rabbit Model Of Hypoxemia,
2015
University of Nebraska-Lincoln
Evaluation Of Peritoneal Microbubble Oxygenation Therapy In A Rabbit Model Of Hypoxemia, Nathan D. Legband, Jameel A. Feshitan, Mark A. Borden, Benjamin S. Terry
Department of Mechanical and Materials Engineering: Faculty Publications
Alternative extrapulmonary oxygenation technologies are needed to treat patients suffering from severe hypoxemia refractory to mechanical ventilation. We previously demonstrated that peritoneal microbubble oxygenation (PMO), in which phospholipid-coated oxygen microbubbles (OMBs) are delivered into the peritoneal cavity, can successfully oxygenate rats suffering from a right pneumothorax. This study addressed the need to scale up the procedure to a larger animal with a splanchnic cardiac output similar to humans. Our results show that PMO therapy can double the survival time of rabbits experiencing complete tracheal occlusion from6.6 ± 0.6 min for the saline controls to 12.2 ± 3.0 min for the …
Electronic Structure Evolution Of Fullerene On Ch3Nh3Pbi3,
2015
University of Rochester
Electronic Structure Evolution Of Fullerene On Ch3Nh3Pbi3, Chenggong Wang, Congcong Wang, Xiaoliang Liu, John Kauppi, Yuchuan Shao, Zhengguo Xiao, Cheng Bi, Jinsong Huang, Yongli Gao
Department of Mechanical and Materials Engineering: Faculty Publications
The thickness dependence of fullerene on CH3NH3PbI3 perovskite film surface has been investigated by using ultraviolet photoemission spectroscopy (UPS), X-ray photoemission spectroscopy (XPS), and inverse photoemission spectroscopy (IPES). The lowest unoccupied molecular orbital and highest occupied molecular orbital (HOMO) can be observed directly with IPES and UPS. It is observed that the HOMO level in fullerene shifts to lower binding energy. The XPS results show a strong initial shift of core levels to lower binding energy in the perovskite, which indicates that electrons transfer from the perovskite film to fullerene molecules. Further deposition of fullerene …
Improving The Sensitivity Of A Near-Infrared Nanocomposite Photodetector By Enhancing Trap Induced Hole Injection,
2015
University of Nebraska-Lincoln
Improving The Sensitivity Of A Near-Infrared Nanocomposite Photodetector By Enhancing Trap Induced Hole Injection, Liang Shen, Yanjun Fang, Qingfeng Dong, Zhengguo Xiao, Jinsong Huang
Department of Mechanical and Materials Engineering: Faculty Publications
We report the enhancement of the photoconductive gain of nanocomposite near-infrared photodetectors by a zinc oxide nanoparticles (ZnO NPs) rich surface at the nanocomposite/cathode interface. An argon plasma etching process was used to remove polymer at the surface of nanocomposite films, which resulted in a ZnO NPs rich surface. The other way is to spin-coat a thin layer of ZnO NPs onto the nanocomposite layer. The ZnO NPs rich surface, which acts as electron traps to induce secondary hole injection under reverse bias, increased hole injection, and thus the external quantum efficiency by 2–3 times. The darkcurrent declined one order …
