Mode-Converted Ultrasonic Scattering In Polycrystals With
Elongated Grains,
2016
U.S. Army Research Laboratory, Aberdeen
Mode-Converted Ultrasonic Scattering In Polycrystals With Elongated Grains, Andrea P. Arguelles, Christopher M. Kube, Ping Hu, Joseph A. Turner
Department of Mechanical and Materials Engineering: Faculty Publications
Elastic wave scattering is used to study polycrystalline media for a wide range of applications. Received signals, which include scattering from the randomly oriented grains comprising the polycrystal, contain information from which useful microstructural parameters may often be inferred. Recently, a mode-converted diffuse ultrasonic scattering model was developed for evaluating the scattered response of a transverse wave from an incident longitudinal wave in a polycrystalline medium containing equiaxed single-phase grains with cubic elastic symmetry. In this article, that theoretical mode-converted scattering model is modified to account for grain elongation within the sample. The model shows the dependence on scattering angle …
Expanded 3d Nanofiber Scaffolds: Cell Penetration, Neovascularization, And Host Response,
2016
University of Nebraska Medical Center
Expanded 3d Nanofiber Scaffolds: Cell Penetration, Neovascularization, And Host Response, Jiang Jiang, Zhuoran Li, Hongjun Wang, Yue Wang, Mark A. Carlson, Matthew J. Teusink, Matthew R. Macewan, Linxia Gu, Jingwei Xie
Department of Mechanical and Materials Engineering: Faculty Publications
Herein, a robust method to fabricate expanded nanofiber scaffolds with controlled size and thickness using a customized mold during the modified gas-foaming process is reported. The expansion of nanofiber membranes is also simulated using a computational fluid model. Expanded nanofiber scaffolds implanted subcutaneously in rats show cellular infiltration, whereas non-expanded scaffolds only have surface cellular attachment. Compared to unexpanded nanofiber scaffolds, more CD68+ and CD163+ cells are observed within expanded scaffolds at all tested time points post-implantation. More CCR7+ cells appear within expanded scaffolds at week 8 post-implantation. In addition, new blood vessels are present within the expanded scaffolds at …
Enhancing Stability And Efficiency Of Perovskite Solar Cells With Crosslinkable Silane-Functionalized And Doped Fullerene,
2016
University of Nebraska-Lincoln
Enhancing Stability And Efficiency Of Perovskite Solar Cells With Crosslinkable Silane-Functionalized And Doped Fullerene, Yang Bai, Qingfeng Dong, Yuchuan Shao, Yehao Deng, Qi Wang, Liang Shen, Dong Wang, Wei Wei, Jinsong Huang
Department of Mechanical and Materials Engineering: Faculty Publications
The instability of hybrid perovskite materials due to water and moisture arises as one major challenge to be addressed before any practical application of the demonstrated high efficiency perovskite solar cells. Here we report a facile strategy that can simultaneously enhance the stability and efficiency of p–i–n planar heterojunction-structure perovskite devices. Crosslinkable silane molecules with hydrophobic functional groups are bonded onto fullerene to make the fullerene layer highly water-resistant. Methylammonium iodide is introduced in the fullerene layer for n-doping via anion-induced electron transfer, resulting in dramatically increased conductivity over 100-fold. With crosslinkable silane-functionalized and doped fullerene electron transport layer, the …
Stabilized Wide Bandgap MapbbrXI3– X Perovskite By Enhanced Grain Size And Improved Crystallinity,
2016
University of Nebraska–Lincoln
Stabilized Wide Bandgap MapbbrXI3– X Perovskite By Enhanced Grain Size And Improved Crystallinity, Miao Hu, Cheng Bi, Yongbo Yuan, Yang Bai, Jinsong Huang
Department of Mechanical and Materials Engineering: Faculty Publications
Methylammonium lead trihalide perovskite (MAPbX3, where MA is methylammonium, and X is a halide)-based solar cells have been intensively investigated recently, with the demonstrated certified solar power conversion efficiency (PCE) exceeding 20%. To further boost the PCE to beyond the Schockley–Queisser limit, tandem structured solar cells have been investigated based on integrating MAPbX3 and low bandgap solar cells. However, the efficiency of the two-terminal integrated perovskite-silicon tandem cells is still low. The best reported efficiency of 13.7% for this type of tandem cells is far smaller than the individual cells yet, partially due to the limited performance …
Ultrahigh Sensitivity Of Methylammonium Lead
Tribromide Perovskite Single Crystals To
Environmental Gases,
2016
University of Groningen
Ultrahigh Sensitivity Of Methylammonium Lead Tribromide Perovskite Single Crystals To Environmental Gases, Hong-Hua Fang, Sampson Adjokatse, Haotong Wei, Jie Yang, Graeme R. Blake, Jinsong Huang, Jacky Even, Maria Antonietta Loi
Department of Mechanical and Materials Engineering: Faculty Publications
One of the limiting factors to high device performance in photovoltaics is the presence of surface traps. Hence, the understanding and control of carrier recombination at the surface of organic-inorganic hybrid perovskite is critical for the design and optimization of devices with this material as the active layer. We demonstrate that the surface recombination rate (or surface trap state density) inmethylammonium lead tribromide (MAPbBr3) single crystals can be fully and reversibly controlled by the physisorption of oxygen and water molecules, leading to a modulation of the photoluminescence intensity by over two orders of magnitude.We report an unusually low surface recombination …
The Metal/Organic Interface In Cobalt/Vinylidene Fluoride
Heterostructures,
2016
University of Nebraska-Lincoln
The Metal/Organic Interface In Cobalt/Vinylidene Fluoride Heterostructures, Keith Foreman, E Echeverria, Mark A. Koten, R. M. Lindsay, N. Hong, Jeffrey E. Shield, Shireen Adenwalla
Shireen Adenwalla Papers
Organic-based electronic devices are rapidly increasing in popularity, making it essential to understand and characterize the interface between organic materials and metallic electrodes. This work reports on the characterization of the interface between thin films of an emerging organic ferroelectric, vinylidene fluoride (VDF) oligomer, and Co, an important high Curie temperature ferromagnet. Using a wide battery of experimental techniques, it is shown that VDF oligomer thin films as thin as 15 nm can halt, or prevent, Co oxidization in atmospheric conditions, a necessary condition for device applications. Selectivity of magnetic properties, such as remanent magnetization, is enabled by the clarification …
Ferroelectric Characterization And Growth Optimization Of Thermally Evaporated Vinylidene Fluoride Thin Films,
2016
University of Nebraska-Lincoln
Ferroelectric Characterization And Growth Optimization Of Thermally Evaporated Vinylidene Fluoride Thin Films, Keith Foreman, N. Hong, C. Labedz, C. Shearer, Stephen Ducharme, Shireen Adenwalla
Shireen Adenwalla Papers
Organic thin films have numerous advantages over inorganics in device processing and price. The large polarization of the organic ferroelectric oligomer vinylidene fluoride (VDF) could prove useful for both device applications and the investigation of fundamental physical phenomena. A VDF oligomer thin film vacuum deposition process, such as thermal evaporation, preserves film and interface cleanliness, but is challenging, with successful deposition occurring only within a narrow parameter space. We report on the optimal deposition parameters for VDF oligomer thin films, refining the parameter space for successful deposition, resulting in a high yield of robust ferroelectric films. In particular, we investigate …
An Assessment Of The Validity Of The Kinetic Model For Liquid-Vapor Phase Change By Examining Cryogenic Propellants,
2016
Michigan Technological University
An Assessment Of The Validity Of The Kinetic Model For Liquid-Vapor Phase Change By Examining Cryogenic Propellants, Kishan Bellur
Dissertations, Master's Theses and Master's Reports
Evaporation is ubiquitous in nature and occurs even in a microgravity space envi- ronment. Long term space missions require storage of cryogenic propellents and an accurate prediction of phase change rates. Kinetic theory has been used to model and predict evaporation rates for over a century but the reported values of accommodation coefficients are highly inconsistent and no accurate data is available for cryogens. The proposed study involves a combined experimental and computational approach to ex- tract the accommodation coefficients. Neutron imaging is used as the visualization technique due to the difference in attenuation between the cryogen and the metallic …
Single Particle-Inductively Coupled Plasma-Mass Spectrometry Technology Development For Metallic Nanoparticle Characterization In Complex Matrices,
2016
Missouri University of Science and Technology
Single Particle-Inductively Coupled Plasma-Mass Spectrometry Technology Development For Metallic Nanoparticle Characterization In Complex Matrices, Yongbo Dan
Doctoral Dissertations
"As the rapid growing of nanotechnology, the release of engineered nanoparticles (ENPs) into the environment is inevitable. After entering the real environment, ENPs tend to react with different components of the ecosystem (e.g. water, soil, air, plants) and make their characterization difficult. Analyzing ENPs in these complex matrices still remains as a grand challenge. ENPs characterization is normally the first step of risk assessment. Current analytical techniques have shown some limitations in revealing the unique characteristics of ENPs in complex matrices and reliable analytical techniques are in urgent need. Single particle inductively coupled plasma mass spectrometry (SP-ICP-MS) is an emerging …
Slip-Jump Model For Carbon Combustion Synthesis Of Complex Oxide Nanoparticles,
2016
The University of Texas Rio Grande Valley
Slip-Jump Model For Carbon Combustion Synthesis Of Complex Oxide Nanoparticles, A. A. Markov, Mkhitar A. Hobosyan, Karen S. Martirosyan
Physics & Astronomy Faculty Publications
Carbon Combustion Synthesis of Oxides (CCSO) is a promising method to produce submicron- and nano- sized complex oxides. The CCSO was successfully utilized for producing several complex oxides, a complete theoretical model including the sample porosity, fl ow parameters and reaction energetics is needed to predict the combustion parameters for CCSO. In this work, we studied the ignition temperature and combustion wave axial temperature distribution, activation energy, combustion heat and thermal losses for a typical CCSO synthesis for cylindrical samples of Ni-Zn ferrites with high (>85%) porosity. We developed a two level combustion model of chemically active nano-dispersed mixture, …
Intrinsic And Metal-Doped Gallium Oxide Based High-Temperature Oxygen Sensors For Combustion Processes,
2016
University of Texas at El Paso
Intrinsic And Metal-Doped Gallium Oxide Based High-Temperature Oxygen Sensors For Combustion Processes, Ernesto Javier Rubio
Open Access Theses & Dissertations
Currently, there is enormous interest in research, development and optimization of the combustion processes for energy harvesting. Recent statistical and economic analyses estimated that by improving the coal-based firing/combustion processes in the power plants, savings up to ~$450-500 million yearly can be achieved. Advanced sensors and controls capable of withstanding extreme environments such as high temperatures, highly corrosive atmospheres, and high pressures are critical to such efficiency enhancement and cost savings. For instance, optimization of the combustion processes in power generation systems can be achieved by sensing, monitoring and control of oxygen, which is a measure of the completeness of …
Electrokinetic Phenomena In Pencil Lead-Based Microfluidics,
2016
Old Dominion University
Electrokinetic Phenomena In Pencil Lead-Based Microfluidics, Yashar Bashirzadeh, Venkat Maruthamuthu, Shizhi Qian
Mechanical & Aerospace Engineering Faculty Publications
Fabrication of microchannels and associated electrodes to generate electrokinetic phenomena often involves costly materials and considerable effort. In this study, we used graphite pencil-leads as low cost, disposable 3D electrodes to investigate various electrokinetic phenomena in straight cylindrical microchannels, which were themselves fabricated by using a graphite rod as the microchannel mold. Individual pencil-leads were employed as the micro-electrodes arranged along the side walls of the microchannel. Efficient electrokinetic phenomena provided by the 3D electrodes, including alternating current electroosmosis (ACEO), induced-charge electroosmosis (ICEO), and dielectrophoresis (DEP), were demonstrated by the introduced pencil-lead based microfluidic devices. The electrokinetic phenomena were characterized …
Synthesis Of Porous Carbon Nanosheets And Its Application In Sodium-Ion Battery,
2015
Jiangsu Key Laboratory of New Power Batteries, School of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210023, China;
Synthesis Of Porous Carbon Nanosheets And Its Application In Sodium-Ion Battery, Jing-Fei Zhang, Jing Lu, Xiao-Yu Yang, Yun-Di Huang, Lin Xu, Dong-Mei Sun, Ya-Wen Tang
Journal of Electrochemistry
Owning to sodium’s high abundance, relatively low cost, similar chemical properties to Li and very suitable redox potential of E0(Na+/Na) = -2.71 V versus SHE which is only 0.3 V above that of lithium, rechargeable sodium ion battery hold much promise as potential alternatives to current lithium ion batteries for energy storage applications. Carbon material is regarded as the most promising anode candidate for sodium ion battery. Particularly, carbon nanosheet with porous structure and high conductivity is expected to have improved sodium ion storage properties. In this paper, we present a two-step pyrolysis-based method for facile …
Intercalation Of Clo4- Into Hopg Investigated By Ec-Stm,
2015
State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, Fujian, China;
Intercalation Of Clo4- Into Hopg Investigated By Ec-Stm, Xiao-Yan Hu, Alice Aliwowe, Jia-Wei Yan, Bing-Wei Mao
Journal of Electrochemistry
The electrochemical intercalation and surface morphology of highly oriented pyrolytic graphite (HOPG) electrode in 2 mol⋅L-1 HClO4 were studied by in situ scanning tunneling microscopy (STM) and cyclic voltammetry (CV). Based on the step-height changes observed before and after the intercalation, the effects of different step sites on intercalation are compared. The feasibility, reversibility and speed of intercalation are discussed. The intercalation ofClO4- into HOPG can be divided into three types depending on the number of graphite layers at the step site: When the layers of graphite are more than three, the intercalation becomes feasible; when …
Electrochemical Properties Of Graphene/Porous Nano-Silicon Anode,
2015
Shanghai Institute of Space Power Sources, Shanghai 200245, China;
Electrochemical Properties Of Graphene/Porous Nano-Silicon Anode, Chun-Li Li, Guang Yang, Ping Zhang, Zhi-Yu Jiang
Journal of Electrochemistry
Porous nano-silicon (Si) was prepared by acid etching Al-Si alloy powder method, and used as an active material for fabricating a grapene/porous nano-Si electrode. The results of SEM and TEM measurements indicated that porous nano-Si powder was uniformly mixed with graphene by emulsification dispersion-ultrasonication method. As an anode for lithium ion battery, the graphene/porous nano-Si electrode presented relatively high performance in 1 mol•L-1LiPF6/EC:DMC = 1:1(by volume) + 1.5% (by mass) VC solution. At the charge and discharge current densities of 0.5A•g-1, the first discharge capacity was 1768.6mAh•g-1with coulombic efficiency of 68.3%. The discharge capacity …
Turning An Organic Semiconductor Into A Low-Resistance Material By Ion Implantation,
2015
Università di Bologna
Turning An Organic Semiconductor Into A Low-Resistance Material By Ion Implantation, Beatrice Fraboni, Alessandra Scidà, Piero Cosseddu, Yongqiang Wang, Michael Nastasi, Silvia Milita, Annalisa Bonfiglio
Nebraska Center for Energy Sciences Research: Publications
We report on the effects of low energy ion implantation on thin films of pentacene, carried out to investigate the efficacy of this process in the fabrication of organic electronic devices. Two different ions, Ne and N, have been implanted and compared, to assess the effects of different reactivity within the hydrocarbon matrix. Strong modification of the electrical conductivity, stable in time, is observed following ion implantation. This effect is significantly larger for N implants (up to six orders of magnitude), which are shown to introduce stable charged species within the hydrocarbon matrix, not only damage as is the case …
Three Dimensional Nanowire Array Piezo-Phototronic And Piezo-Photo-Magnetotronic Sensors,
2015
University of New Orleans
Three Dimensional Nanowire Array Piezo-Phototronic And Piezo-Photo-Magnetotronic Sensors, Satish C. Rai
LSU New Orleans Theses and Dissertations
Piezotronic and piezo-phototronic is a burgeoning field of study which emerges from the coupling of intrinsic materials properties exhibited by non-centrosymmetric semiconductors. In the past decade research efforts were mainly focused on the wurtzite family of 1D nanostructures, with major emphasis on ZnO nanowire nanogenerators, MS piezotronic transistors, LEDs and photodetectors mainly integrated on single nanowires. In view of previously known advantages of charge carrier separation in radial heterojunctions, particularly in type-II core/shell nanowires, it can be anticipated that the performance of photosensing devices can be largely enhanced by piezo-phototronic effect. Moreover, the performance metrics can be further improved in …
Epitaxial Growth Of Si-Ge-Sn Alloys For Optoelectronic Device Application,
2015
University of Arkansas, Fayetteville
Epitaxial Growth Of Si-Ge-Sn Alloys For Optoelectronic Device Application, Aboozar Mosleh
Graduate Theses and Dissertations
Microelectronics industry has experienced a tremendous change over the last few decades and has shown that Moore’s law has been followed by doubling the number of transistors on the chip every 18 months. However, continuous scaling down of the transistors size is reaching the physical limits and data transfer through metal interconnects will not be able to catch up with the increasing data processing speed in the future. Therefore, optical data transfer between chips and on-chip has been widely investigated. Silicon based optoelectronics has received phenomenal attention since Si has been the core material on which microelectronic industry has been …
When 1 + 1 > 2: Nanostructured Composites For Hard Tissue Engineering Applications,
2015
Chapman University
When 1 + 1 > 2: Nanostructured Composites For Hard Tissue Engineering Applications, Vuk Uskoković
Pharmacy Faculty Articles and Research
Multicomponent, synergistic and multifunctional nanostructures have taken over the spotlight in the realm of biomedical nanotechnologies. The most prospective materials for bone regeneration today are almost exclusively composites comprising two or more components that compensate for the shortcomings of each one of them alone. This is quite natural in view of the fact that all hard tissues in the human body, except perhaps the tooth enamel, are composite nanostructures. This review article highlights some of the most prospective breakthroughs made in this research direction, with the hard tissues in main focus being those comprising bone, tooth cementum, dentin and enamel. …
Imaging Thermal Conductivity With Nanoscale Resolution Using A Scanning Spin Probe,
2015
CUNY-City College of New York
Imaging Thermal Conductivity With Nanoscale Resolution Using A Scanning Spin Probe, Abdelghani Laraoui, Halley Aycock-Rizzo, Yang Gao, Xi Lu, Elisa Riedo, Carlos A. Meriles
Department of Mechanical and Materials Engineering: Faculty Publications
The ability to probe nanoscale heat flow in a material is often limited by lack of spatial resolution. Here, we use a diamond-nanocrystal-hosted nitrogen-vacancy centre attached to the apex of a silicon thermal tip as a local temperature sensor. We apply an electrical current to heat up the tip and rely on the nitrogen vacancy to monitor the thermal changes the tip experiences as it is brought into contact with surfaces of varying thermal conductivity. By combining atomic force and confocal microscopy, we image phantom microstructures with nanoscale resolution, and attain excellent agreement between the thermal conductivity and topographic maps. …
