Nanoscience and Nanotechnology Commons^™

Electrocatalysis In Li-S Batteries, Hesham I. Al Salem

Wayne State University Dissertations

Stabilizing polysulfide-shuttle process while ensuring high sulfur loading holds the key to realize high theoretical energy density (2500 Wh/kg) of lithium-sulfur (Li-S) batteries. Though several carbon based porous materials have been used as host structures for sulfur and its intermediate polysulfides, the week adsorption of polysulfides on carbon surface and its poor reaction kinetics limits them from practical application. Here, we preset a novel ‘electcatalysis’ approach to stabilize polysulfide shuttle process and also enhance its red-ox kinetics. As a proof of concept, we have studied in-detail using conventional electrocatalyst i.e Pt/graphene composite, further the same extended to cost-effective electrocatalysts such …

Biomimetic Substrate Control Of Cellular Mechanotransduction, Mohammad Nahid Andalib, Yuris A. Dzenis, Henry J. Donahue, Jung Yul Lim

Department of Mechanical and Materials Engineering: Faculty Publications

Extracellular mechanophysical signals from both static substrate cue and dynamic mechanical loading have strong potential to regulate cell functions. Most of the studies have adopted either static or dynamic cue and shown that each cue can regulate cell adhesion, spreading, migration, proliferation, lineage commitment, and differentiation. However, there is limited information on the integrative control of cell functions by the static and dynamic mechanophysical signals. For example, a majority of dynamic loading studies have tested mechanical stimulation of cells utilizing cultures on flat surfaces without any surface modification. While these approaches have provided significant information on cell mechanotransduction, obtained outcomes …

Characterizing The Boundary Lateral To The Shear Direction Of Deformation Twins In Magnesium, Y. Liu, N. Li, S. Shao, M. Gong, J Wang, R.J. Mccabe, Y. Jiang, C.N. Tome

Department of Mechanical and Materials Engineering: Faculty Publications

The three-dimensional nature of twins, especially the atomic structures and motion mechanisms of the boundary lateral to the shear direction of the twin, has never been characterized at the atomic level, because such boundary is, in principle, crystallographically unobservable.We thus refer to it here as the dark side of the twin. Here, using high-resolution transmission electron microscopy and atomistic simulations, we characterize the dark side of {1012} deformation twins in magnesium. It is found that the dark side is serrated and comprised of {1012} coherent twin boundaries and semi-coherent twist prismatic–prismatic {2110} boundaries that control twin growth. The conclusions of …

Stress-Dependent Ultrasonic Scattering In Polycrystalline Materials, Christopher M. Kube, Christopher A Turner

Department of Mechanical and Materials Engineering: Faculty Publications

Stress-dependent elastic moduli of polycrystalline materials are used in a statistically based model for the scattering of ultrasonic waves from randomly oriented grains that are members of a stressed polycrystal. The stress is assumed to be homogeneous and can be either residual or generated from external loads. The stress-dependent elastic properties are incorporated into the definition of the differential scattering cross-section, which defines how strongly an incident wave is scattered into various directions. Nine stress-dependent differential scattering cross-sections or scattering coefficients are defined to include all possibilities of incident and scattered waves, which can be either longitudinal or (two) transverse …

Graphene Platform For Neural Regenerative Medicine, Tasneem Bouzid, Alexander Sinitskii, Jung Yul Lim

Department of Mechanical and Materials Engineering: Faculty Publications

Graphene is a material composed of a single layer of carbon atoms arranged in a two-dimensional honeycomb lattice. The unique electrical, optical, thermal, and mechanical properties of graphene are extensively exploited for various applications in electronics, energy, and sensors. Studies also proposed the potential of graphene for biomedical applications. The intrinsic characteristics of graphene and its availability for chemical and physical modifications make graphene a promising vehicle for various biomedical applications including drug delivery, bioimaging, disease diagnostics, etc. The chemical structure of graphene and, in turn, its functionality, can be altered by attaching functional groups, which not only modify the …

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 …

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, 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, 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 …

Pulsed Laser Cutting Of Magnesium-Calcium For Biodegradable Stents, M. P. Sealy, Y. B. Guo, J. F. Liu, C. Li

Department of Mechanical and Materials Engineering: Faculty Publications

There is growing interests in the use of biodegradable magnesium implants for cardiovascular and pulmonary applications such as stents. Magnesium is a metal that has the ability to gradually dissolve and absorb into the human body after implantation. There is very little work discussing the relationship between process parameters and cut quality of magnesium stents by laser cutting. The objective of this research is to determine the effect of laser cutting conditions including peak laser power and cutting speed of a millisecond range pulsed laser on kerf geometry, surface topography, surface roughness, and microstructure. An assessment on the experimental work …

Impact Of Patient Factors On Operative Duration During Laparoscopic Cholecystectomy: Evaluation From The National Surgical Quality Improvement Program Database, Bethany Rose Lowndes, Cornelius A. Thiels, Elizabeth B. Habermann, Juliane Bingener, M. Susan Hallbeck, Denny Yu

Department of Mechanical and Materials Engineering: Faculty Publications

BACKGROUND: Patient factors impact laparoscopic cholecystectomy (LC) difficulty, specifically operative duration. This study quantifies the impact of patient factors on LC duration.

METHODS: The national surgery database (American College of Surgeons National Surgical Quality Improvement Program) was reviewed for all elective LC for biliary colic from 2005 to 2013. Multivariate general linear model and logistic regression were used to evaluate patient factors as predictors of operative duration greater than 60 minutes, adjusted for resident involvement and cholangiography.

RESULTS: A total of 24,099 LC met inclusion criteria. Regression analysis found procedure duration greater than 60 minutes was less likely for patients …

A Comparative Study On Machining Capabilities Of Wet And Dry Nanoscale Electro-Machining, Muhammad P. Jahan, Kamlakar P. Rajurkar, Ajay P. Malshe

Department of Mechanical and Materials Engineering: Faculty Publications

Presently, the nano scale electro-machining (nano-EM) process has been demonstrated in both the liquid and air dielectric mediums, which are known as wet and dry nano-EM respectively. In the current study, two important aspects of the nano-EM have been investigated: the minimum possible feature dimension and mass fabrication capability of nano-EM. Firstly, the investigation has been done on the capability of machining graphene at atomic scale with focus on obtaining smallest possible nano-feature using the wet nano-EM. Secondly, the ability of the nano-EM process for the fabrication of arrays of nano-holes has been investigated using dry nano-EM. It was found …

Bioink Properties Before, During And After 3d Bioprinting, Katja Holzl, Shengmao Lin, Liesbeth Tytgat, Sandra Van Vlierberghe, Linxia Gu, Aleksandr Ovsianikov

Department of Mechanical and Materials Engineering: Faculty Publications

Bioprinting is a process based on additive manufacturing from materials containing living cells. These materials, often referred to as bioink, are based on cytocompatible hydrogel precursor formulations, which gel in a manner compatible with different bioprinting approaches. The bioink properties before, during and after gelation are essential for its printability, comprising such features as achievable structural resolution, shape fidelity and cell survival. However, it is the final properties of the matured bioprinted tissue construct that are crucial for the end application. During tissue formation these properties are influenced by the amount of cells present in the construct, their proliferation, migration …

Development Of A Synthetic Gene Network To Modulate Gene Expression By Mechanical Forces, Zoltan Kis, Tania Rodin, Asma Zafar, Zhangxing Lai, Grace Freke, Oliver Fleck, Armando Del Rio Hernandez, Leila Towhidi, Ryan M. Pedrigi, Takayuki Homma, Rob Krams

Department of Mechanical and Materials Engineering: Faculty Publications

The majority of (mammalian) cells in our body are sensitive to mechanical forces, but little work has been done to develop assays to monitor mechanosensor activity. Furthermore, it is currently impossible to use mechanosensor activity to drive gene expression. To address these needs, we developed the first mammalian mechanosensitive synthetic gene network to monitor endothelial cell shear stress levels and directly modulate expression of an atheroprotective transcription factor by shear stress. The technique is highly modular, easily scalable and allows graded control of gene expression by mechanical stimuli in hard-to-transfect mammalian cells. We call this new approach mechanosyngenetics. To insert …

Portable Camera Aided Simulator (Portcas) For Minimally Invasive Surgical Training, Ka-Chun Sui, Carl Nelson, Mohsen Zahiri, Dmitry Oleynikov

Department of Mechanical and Materials Engineering: Faculty Publications

The present disclosure is directed to a system and method for surgical training with low cost, reusable materials and a highly customizable virtual environment for skill-building. According to various embodiments, a surgical training tool is usable in conjunction with a support structure configured to at least partially constrain the tool movement. Meanwhile, the tool is tracked in real-time with off-tool detectors to generate a tool path driving a virtual rendering of the surgical training tool in an operative environment. The virtual rendering may be visually observable via a display device and may include a customizable and/or selectable operative environment with …

Secondary Pool Boiling Effects, C. Kruse, A. Tsubaki, C. A. Zuhlke, T. P. Anderson, Dennis R. Alexander, George Gogos, Sidy Ndao

Department of Mechanical and Materials Engineering: Faculty Publications

A pool boiling phenomenon referred to as secondary boiling effects is discussed. Based on the experimental trends, a mechanism is proposed that identifies the parameters that lead to this phenomenon. Secondary boiling effects refer to a distinct decrease in the wall superheat temperature near the critical heat flux due to a significant increase in the heat transfer coefficient. Recent pool boiling heat transfer experiments using femtosecond laser processed Inconel, stainless steel, and copper multiscale surfaces consistently displayed secondary boiling effects, which were found to be a result of both temperature drop along the microstructures and nucleation characteristic length scales. The …

Experimental Explanation Of The Formation Mechanism Of Surface Mound-Structures By Femtosecond Laser On Polycrystalline Ni60Nb40, Edwin Peng, A. Tsubaki, Craig A. Zuhlke, Meiyu Wang, Ryan Bell, Michael J. Lucis, Troy P. Anderson, Dennis R. Alexander, George Gogos, Jeffrey E. Shield

Department of Mechanical and Materials Engineering: Faculty Publications

Femtosecond laser surface processing (FLSP) is an emerging technique for creating functionalized surfaces with specialized properties, such as broadband optical absorption or superhydrophobicity/ superhydrophilicity. It has been demonstrated in the past that FLSP can be used to form two distinct classes of mound-like, self-organized micro/nanostructures on the surfaces of various metals. Here, the formation mechanisms of below surface growth (BSG) and above surface growth (ASG) mounds on polycrystalline Ni₆₀Nb₄₀ are studied. Cross-sectional imaging of these mounds by focused ion beam milling and subsequent scanning electron microscopy revealed evidence of the unique formation processes for each class of …

Dose Dependence Of Radiation Damage In Nano-Structured Amorphous Sioc/Crystalline Fe Composite, Qing Su, Lloyd Price, Lin Shao, Michael Nastasi

Department of Mechanical and Materials Engineering: Faculty Publications

Through examination of radiation tolerance properties of amorphous silicon oxycarbide (SiOC) and crystalline Fe composite to averaged damage levels, from approximately 8 to 30 displacements per atom (dpa), we demonstrated that the Fe/SiOC interface and the Fe/amorphous Fe_xSi_yO_z interface act as efficient defect sinks and promote the recombination of vacancies and interstitials. For thick Fe/SiOC multilayers, a clear Fe/SiOC interface remained and no irradiation-induced mixing was observed even after 32 dpa. For thin Fe/SiOC multilayers, an amorphous Fe_xSi_yO_z intermixed layer was observed to form at 8 dpa, but no further …

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 …

An Analysis Of Plasticity In The Rat Respiratory System Following Cervical Spinal Cord Injury And The Application Of Nanotechnology To Induce Or Enhance Recovery Of Diaphragm Function, Janelle Lorien Walker

Wayne State University Dissertations

Second cervical segment spinal cord hemisection (C2Hx) results in ipsilateral hemidiaphragm paralysis. However, the intact latent crossed phrenic pathway can restore function spontaneously over time or immediately following drug administration.

WGA bound fluorochromes were administered to identify nuclei associated with diaphragm function in both the acute and chronic C2Hx models. WGA is unique in that it undergoes receptor mediated endocytosis and is transsynaptically transported across select physiologically active synapses. Comparison of labeling in the acutely injured to the chronically injured rat provided an anatomical map of spinal and supraspinal injury induced synaptic plasticity. The plasticity occurs over time in the …

Diagnostics And Degradation Investigations Of Li-Ion Battery Electrodes Using Single Nanowire Electrochemical Cells, Naveen Kumar Reddy Palapati, Naveen Kumar Reddy Palapati

Theses and Dissertations

Portable energy storage devices, which drive advanced technological devices, are improving the productivity and quality of our everyday lives. In order to meet the growing needs for energy storage in transportation applications, the current lithium-ion (Li-ion) battery technology requires new electrode materials with performance improvements in multiple aspects: (1) energy and power densities, (2) safety, and (3) performance lifetime. While a number of interesting nanomaterials have been synthesized in recent years with promising performance, accurate capabilities to probe the intrinsic performance of these high-performance materials within a battery environment are lacking. Most studies on electrode nanomaterials have so far used …

Peptide-Functionalized Magnetic Nanoparticles For Cancer Therapy Applications, Anastasia K. Hauser

Theses and Dissertations--Chemical and Materials Engineering

Lung cancer is one of the leading causes of cancer deaths in the United States. Radiation and chemotherapy are conventional treatments, but they result in serious side effects and the probability of tumor recurrence remains high. Therefore, there is an increasing need to enhance the efficacy of conventional treatments. Magnetic nanoparticles have been previously studied for a variety of applications such as magnetic resonance imaging contrast agents, anemia treatment, magnetic cell sorting and magnetically mediated hyperthermia (MMH). In this work, dextran coated iron oxide nanoparticles were developed and functionalized with peptides to target the nanoparticles to either the extracellular matrix …

Synthesis Of Titania Thin Films With Controlled Mesopore Orientation: Nanostructure For Energy Conversion And Storage, Suraj R. Nagpure

Theses and Dissertations--Chemical and Materials Engineering

This dissertation addresses the synthesis mechanism of mesoporous titania thin films with 2D Hexagonal Close Packed (HCP) cylindrical nanopores by an evaporation-induced self-assembly (EISA) method with Pluronic surfactants P123 and F127 as structure directing agents, and their applications in photovoltaics and lithium ion batteries. To provide orthogonal alignment of the pores, surface modification of substrates with crosslinked surfactant has been used to provide a chemically neutral surface. GISAXS studies show not only that aging at 4°C facilitates ordered mesostructure development, but also that aging at this temperature helps to provide orthogonal orientation of the cylindrical micelles which assemble into an …

Electric Field Controlled Strain Induced Switching Of Magnetization Of Galfenol Nanomagnets In Magneto-Electrically Coupled Multiferroic Stack, Hasnain Ahmad

Theses and Dissertations

The ability to control the bi-stable magnetization states of shape anisotropic single domain nanomagnets has enormous potential for spawning non-volatile and energy-efficient computing and signal processing systems. One of the most energy efficient switching methods is to adopt a system of a 2-phase multiferroic nanomagnet, where a voltage applied on the piezoelectric layer generates a strain in it and the strain is elastically transferred to the magnetostrictive nanomagnet which rotates the magnetization states of the nanomagnet at room temperature via the converse magnet-electric effect. Recently, it has been demonstrated that the magnetization of a Co nanomagnet can be switched between …

Hybrid Straintronics-Spintronics: Energy-Efficient Non-Volatile Devices For Boolean And Non-Boolean Computation, Ayan K. Biswas

Theses and Dissertations

Research in future generation computing is focused on reducing energy dissipation while maintaining the switching speed in a binary operation to continue the current trend of increasing transistor-density according to Moore’s law. Unlike charge-based CMOS technology, spin-based nanomagnetic technology, based on switching bistable magnetization of single domain shape-anisotropic nanomagnets, has the potential to achieve ultralow energy dissipation due to the fact that no charge motion is directly involved in switching. However, switching of magnetization has not been any less dissipative than switching transistors because most magnet switching schemes involve generating a current to produce a magnetic field, or spin transfer …

Iron Phosphide Nanostructures As An Efficient Bifunctional Catalysts For Water Splitting, Nikitaa Ashokan

Masters Theses

"The first part of this thesis work focuses on developing a bifunctional catalyst for electrochemical water splitting encompassing both oxygen and hydrogen evolution. A highly efficient catalyst is necessary to improve kinetics of the sluggish four electron process for oxygen evolution reaction (OER) and two-electron process for hydrogen evolution reaction (HER). Recently, transition metal phosphides have gained increasing interest in this field because of their good electrical conductivity properties as well as better catalytic activity. Many transition-metal phosphides are being considered for this application and iron phosphide (FeP) has proved to be a good HER catalyst. In this work, we …

Tracking Silver, Gold, And Titanium Dioxide Nanoparticles Through Drinking Water Systems By Single Particle - Inductively Coupled Plasma - Mass Spectrometry, Ariel Renee Donovan

Masters Theses

"Single particle (SP)-ICP-MS methods were developed to characterize and quantify Ti-containing, titanium dioxide, silver, and gold NP concentration, size, size distribution and dissolved metal element concentration in surface water and treated drinking water. The effectiveness of conventional drinking water treatments (including lime softening, alum coagulation, filtration, and disinfection) to remove NPs from surface water was evaluated using six-gang stirrer jar test simulations. Six-gang stirrers were used to simulate drinking water treatments including lime softening, alum coagulation, powdered activated carbon sorption, filtration, and disinfection by free chlorine. Lime softening effectively removed most nanoparticles added. Source and drinking waters from three large …

Dynamic Atomistic Study Of Tunnel Functions In Nanostructured Transitional Metal Oxides, Yifei Yuan

Dissertations, Master's Theses and Master's Reports

Alpha (α-) MnO₂ is a well know transitional metal oxide possessing one dimensional 2×2 (4.6 × 4.6 Ų) tunnels for accommodation of various ions. Such a characteristic tunneled structure has enabled the wide applications of α-MnO₂ in the fields of ion exchange, molecular sieves, biosensor, catalysis and energy storage. This PhD dissertation focuses on the dynamic study of ion transport functionality of α-MnO₂ at atomic level using an aberration corrected scanning transmission electron microscopy equipped with a special holder with a scanning tunneling microscopy probe.

The wide application of in situ TEM studying the dynamic …

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 …

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, …