Nanoscience and Nanotechnology Commons^™

Multifunctional Operational Component For Robotic Devices, Shane M. Farritor, Amy Lehman, Mark Rentschler

Department of Mechanical and Materials Engineering: Faculty Publications

The various embodiments disclosed herein relate to modular medical devices, including various devices with detachable modular components and various devices with pivotally attached modular components. Additional embodiments relate to procedures in which various of the devices are used cooperatively. Certain embodiments of the medical devices are robotic in vivo devices.

Scaffold Structural Microenvironmental Cues To Guide Tissue Regeneration In Bone Tissue Applications, Xuening Chen, Hongyuan Fan, Xiaowei Deng, Lina Wu, Tao Yi, Linxia Gu, Changchun Zhou, Yujiang Fan, Xingdong Zhang

Department of Mechanical and Materials Engineering: Faculty Publications

In the process of bone regeneration, new bone formation is largely affected by physico-chemical cues in the surrounding microenvironment. Tissue cells reside in a complex scaffold physiological microenvironment. The scaffold should provide certain circumstance full of structural cues to enhance multipotent mesenchymal stem cell (MSC) differentiation, osteoblast growth, extracellular matrix (ECM) deposition, and subsequent new bone formation. This article reviewed advances in fabrication technology that enable the creation of biomaterials with well-defined pore structure and surface topography, which can be sensed by host tissue cells (esp., stem cells) and subsequently determine cell fates during differentiation. Three important cues, including scaffold …

Complementary Microscopy Techniques Applied For Characterizing The Localized Nanoscale Structure Of Poly (Vinylidene Fluoride), Wen Qian, Shuo Sun, Charles Nguyen, Wenlong Li, Stephen Ducharme, Joesph A. Turner

Department of Mechanical and Materials Engineering: Faculty Publications

Poly (vinylidenefluoride) (PVDF), a well-recognized electroactive polymer, has been studied extensively over many decades. Recently, there has been increasing interest in tuning the electrical properties of PVDF from ferroelectric to piezoelectric and to pyroelectric, which can be attained via controlling the microscale structure down to the nanoscale structure [1-2]. To optimize the preparation conditions of PVDF and its copolymers, as well as to improve the performance for many applications, comprehensive analytical techniques are of great importance. In this paper, we demonstrate complementary nanoscale characterization and measurement techniques, by conducting a systematic and coordinated study involving scanning electron microscopy (SEM), high …

Graphene As A Solid-State Ligand For Palladium Catalyzed Cross-Coupling Reactions, Yuan Yang

Theses and Dissertations

Palladium-catalyzed carbon-carbon cross-coupling reactions have emerged a broadly useful, selective and widely applicable method to synthesize pharmaceutical active ingredients. As currently practiced in the pharmaceutical industry, homogeneous Pd catalysts are typically used in cross-coupling reactions. The rational development of heterogeneous catalysts for cross-coupling reactions is critical for overcoming the major drawbacks of homogeneous catalysis including difficulties in the separation, purification, and quality control process in drug production. In order to apply heterogeneous catalysis to flow reactors that may overcome this limitation, the catalyst must be strongly bound to a support, highly stable with respect to leaching, and highly active. While …

Tissue Stresses In Stented Coronary Arteries With Different Geometries: Effect Of The Relation Between Stent Length And Lesion Length, Xiang Shen, Song Ji, Yong-Quan Deng, Hong-Fei Zhu, Jia-Bao Jiang, Linxia Gu

Department of Mechanical and Materials Engineering: Faculty Publications

In-stent restenosis after stent deployment remains an obstruction in the long-term benefits of stenting. This study sought to investigate the influence of the relation between stent length and lesion length on the mechanics of the arterial wall with different geometries, including straight and tapered vessels. Results showed that when the length of the stent was longer than the lesion length, the maximum stress in plaque and vessel increased as the length of stent increased. When the length of the stent was shorter than the lesion length, the vessel stress induced by stent inflation was lower; both ends of the stenosis …

Experimental Measurement Of Dolphin Thrust Generated During A Tail Stand Using Dpiv, Frank E. Fish, Terrie M. Williams, Erica Sherman, Yae Eun Moon, Vicki Wu, Timothy Wei

Department of Mechanical and Materials Engineering: Faculty Publications

Estimation of force generated by dolphins has long been debated. The problem was that indirect estimates of force production for dolphins resulted in low values that could not be validated. Bubble digital particle image velocimetry (DPIV) measured hydrodynamic force production for swimming dolphins and demonstrated high force production. To validate the bubble DPIV and reconcile force production measurements, two bottlenose dolphins (Tursiops truncatus) performing tail stands were measured with bubble DPIV. Microbubbles were generated from a finely porous hose and compressed air source. Displacement of the bubbles by the propulsive motions of the dolphin was tracked with a …

Engineering Zinc Oxide Nanoparticles To Be Used As Nanofertilizers, Zeinah Elhaj Baddar

Theses and Dissertations--Plant and Soil Sciences

Zinc deficient soils, or soils with low Zn bioavailability, are widespread, which exacerbates Zn deficiency in human as crops grown on these soils have low Zn content. Often crop yields are also compromised. Fertilizers based on soluble Zn salts often have limited efficacy in such soils. In this research, we evaluate the performance of polymer coated and bare ZnO nanoparticles (NPs) in an attempt to overcome limitations of soluble Zn salts in alkaline soils. We first synthesized 20-30 nm bare ZnO NPs with different surface chemistries to impart colloidal stability to the particles. Bare ZnO were treated in phosphate solution …

Lanthanide-Based Core-Shell Nanoparticles As Multifunctional Platforms For Targeted Radionuclide Therapy And Multimodal Molecular Imaging, Miguel Toro-Gonzalez

Theses and Dissertations

Lanthanide phosphate (LnPO₄) and lanthanide vanadate (LnVO₄) nanoparticles (NPs) are promising platforms for theranostic applications because of their chemical stability, low solubility, low toxicity, and unique luminescence and magnetic properties. Motivated by the high radiation resistance and ability to host actinides of naturally occurring lanthanide-based compounds, LnPO₄ and LnVO₄ NPs were studied as radionuclide carriers for targeted radionuclide therapy using in vivoα-generators, ²²³Ra, ²²⁵Ac, and ²²⁷Th. The implementation of these radionuclides has shown potential for the treatment of micrometastases and solid tumors as well as challenges in the retention of …

Preparation And Characterization Of Nickel Based Nanocomposite Coatings With Enhanced Mechanical And Surface Properties, Malay Kumar Das

Chulalongkorn University Theses and Dissertations (Chula ETD)

Ni-W alloy and Ni-W/diamond monolayer and multilayer composite coatings were prepared by electrodeposition from a Ni-W plating bath with diamond particles suspended into the bath. Ni-W/diamond composite coatings were also prepared with varying amounts of Cobalt sulphate additives. The morphology and the composition of the deposits was investigated by means of SEM and EDS, respectively. The effect of operating conditions and additives on the Ni-W coatings were analyzed. The effect of the plating parameters, composite particle size, multilayer deposits and cobalt additives on microstructure and mechanical properties of the Ni-W/diamond composite coatings was investigated. The electrodeposited Ni-W/diamond deposits reported a …

Preparation Of Graphene Nanocomposites For Anticorrosion And Sensors, Nadtinan Promphet

Chulalongkorn University Theses and Dissertations (Chula ETD)

This dissertation focused on the development of graphene (GO) nanocomposite coating to improve various substrate properties for the sensor application, which is divided into 2 main parts. The first part is the development of GO incorporated into electroless nickel phosphorus (NiP) coating to improve the properties of metal for electrochemical sensor application. Nickel phosphorus - titanium dioxide sol - reduced graphene oxide (NiP-TiO2 sol -RGO) coated surface was successfully prepared by one-pot electroless deposition on the steel substrate. The results show that the homogeneously formation of water-repellent RGO film covering on the coated surface leading to improve the corrosion resistance …

Fundamental Studies Of Chemical Stability And Carrier Process In Hybrid Perovskite Materials, Jue Gong

Graduate Research Theses & Dissertations

This dissertation comprehensively studies the optoelectronic properties of organic-inorganic hybrid perovskites to fundamentally answer their foundations of outstanding performance on solar cells, photodetectors, nanowire lasers and other optoelectronic applications. Specifically, a novel type of charge carrier-lattice interaction was discovered in perovskite methylammonium lead iodide (CH3NH3PbI3), where photoluminescence lifetime of photoinduced carriers is strongly dependent on the rotational frequency of CH3NH3+, as modulated via substitution of hydrogens with deuterium atoms in the organic cation. In addition, two-dimensional Ruddlesden-Popper perovskite (CH3NH3)2Pb(SeCN)2I2 was first synthesized and characterized in the field, and its photoluminescence properties were systematically examined. The existence of intensive photoluminescence peak …

Investigating The Effects Of Orientation Control Of Graphene Nanoplatelet Suspensions By A Magnetic Field On The Viscosity Of A Nanofluid System, Radhika Iyer

Graduate Research Theses & Dissertations

In this investigation, the rheological behavior of paraffin oil containing diamagnetic suspensions is characterized under varying magnetic field conditions. The particles suspended in the white paraffin oil at mass concentrations of 0.1, 0.3, 0.5, 0.7 and 1% m/m are two-dimensional graphene nanoplatelets with an average thickness of 2 – 8 nm. Rheological experiments were conducted using a Brookfield DV2T viscometer with a modified cylindrical spindle over the range of shear rates between 192 s-1 to 1928 s-1. A Neodymium N42 ring magnet with a surface strength of 1.32 T generated the magnetic field conditions for the rheological experiments and was …

The Role Of Microenvironment Reagent Solubility On Reaction Kinetics Of 4-Nitrophenol Reduction, Michael P. Zeevi, Andrew Harrison, Christina Tang

UROP Posters

The Role of Microenvironment Reagent Solubility on Reaction Kinetics of 4-Nitrophenol Reduction

Michael Zeevi¹ with Andrew Harrison¹ and Christina Tang, PhD¹

¹Department of Chemical and Life Science Engineering, VCU School of Engineering

Introduction: Nanoparticles are of increasing interest due to their high surface area to volume ratio, as well as that they enable fine-tuning of the reaction microenvironment. Through flash nanoprecipitation, core-shell polymer nanoreactors were formed by directed self-assembly. Using the reduction of 4-nitrophenol as a model reduction reaction, we investigated the effect of reagent solubility in the nanoreactor microenvironment’s on nanoreactor kinetics.

Methods: The standard …

Magnetic And Catalytic Properties Of Transition Metal Doped Mos2 Nanocrystals, Luis Martinez

Open Access Theses & Dissertations

Magnetism and catalytic activity of nanoscale layered two-dimensional (2D) transition metal dichalcogenides (TMDs) have gained an increasing research interest in the recent past. To broaden the current knowledge and understanding on this subject, in this work, together with my collaborators, I study the magnetic and electrocatalytic properties of hydrothermally grown pristine and transition metal doped (10% of Co, Ni, Fe and Mn) 2H-MoS2 nanosheets/nanocrystals (NCs), with the particle size of 25-30 nm. A broad range of experimental measurements such as x-ray diffraction, transmission electron microscopy, x-ray photo absorption spectroscopy, Raman spectroscopy, magnetic, catalytic and electron spin resonance have been employed …

Exploring The Effects Of Zinc Nanoparticle Concentration, Antioxidant, And Media On Cilantro (Coriandrum Sativum), And Radish (Raphanus Sativus) Plants Growth, Venkata Laxma Reddy Pullagurala

Open Access Theses & Dissertations

Engineered nanomaterials (ENMs) have proven to be one of the emerging chemicals of concern in the contemporary times. Soil acts as one of the major sinks of these ENMs. Reports have shown that ENMs have varied effects on soil biota. Particularly, their effects on plants are inconsistent. Amongst these ENMs, ZnO nanoparticles (nZnO) are the fourth largest raw materials in the nanotechnology industry. Globally, it is estimated that around 34,000 tons of n ZnO are utilized per year. The nZnO exposure on terrestrial plants yielded both beneficial as well as detrimental effects. Recently, there is an emerging evidence about the …

Development Of Antimicrobial Chitosan Based Nanofiber Dressings For Wound Healing Applications, Lee Cremar, Jorge Gutierrez, Jennifer Martinez, Luis A. Materon, Robert Gilkerson, Fenghua Xu, Karen Lozano

Mechanical Engineering Faculty Publications

Objective(s): Chitosan based composite fine fibers were successfully produced via a centrifugal spinning technology. This study evaluates the ability of the composites to function as scaffolds for cell growth while maintaining an antibacterial activity.

Materials and Methods: Two sets of chitosan fiber composites were prepared, one filled with anti-microbial silver nanoparticles and another one with cinnamaldeyhde. Chitosan powder was dissolved in trifluoroacetic acid and dichloromethane followed by addition of the fillers. The fiber output was optimized by configuring the polymer weight concentration (7, 8, and 9 w/w% chitosan) and applied angular velocity (6000-9000 RPM) within the spinning process.

Results: …

Engineered Nanomaterials And Human Health: Part 1. Preparation, Functionalization And Characterization (Iupac Technical Report), Vladimir Gubala, Linda J. Johnston, Harald Friedrich Krug, Colin J. Moore, Christopher K. Ober, Michael Schwenk, Michel R. Vert

Reports

Research on engineered nanomaterials (ENM) has progressed rapidly from the very early stages of studying their unique, size-dependent physicochemical properties and commercial exploration to the development of products that influence our everyday lives. We have previously reviewed various methods for synthesis, surface functionalization, and analytical characterization of ENM in a publication titled 'Engineered Nanomaterials: Preparation, Functionalization and Characterization'. In this second, inter-linked document, we first provide an overview of important applications of ENM in products relevant to human healthcare and consumer goods, such as food, textiles, and cosmetics. We then highlight the challenges for the design and development of new …

Plasmon-Enhanced Optical Sensing By Engineering Metallic Nanostructures, Peng Zheng

Graduate Theses, Dissertations, and Problem Reports (ETD)

The world’s booming population projected to reach 10 billion by 2050 causes enormous stresses on environmental safety, food supply, and healthcare, which in return threatens human civilizations. One of the most promising solutions lies at innovating point-of-care (POC) sensing technologies to conduct detection of environmental hazards, monitoring of food safety, and early diagnosis of diseases in a timely and accurate manner. The discovery of surface-enhanced spectroscopy in the 1970s has significantly stimulated research on light-matter interaction which gives rise to enhanced optical phenomena such as surface-enhanced Raman scattering (SERS), plasmon-enhanced fluorescence (PEF), and particularly, they have found enormous applications in …

An Integrated Microstructural-Nanomechanical-Chemical Approach To Examine Material-Specific Characteristics Of Cementitious Interphase Regions, Mahdieh Khedmati, Yong-Rak Kim, Joesph A. Turner, Hani Alanazi, Charles Nguyen

Department of Mechanical and Materials Engineering: Faculty Publications

Effective properties and structural performance of cementitious mixtures are substantially governed by the quality of the interphase region because it acts as a bridge transferring forces between aggregates and a binding matrix and is generally susceptible to damage. As alternative binding agents like alkali-activated precursors have obtained substantial attention in recent years, there is a growing need for fundamental knowledge to uncover interphase formation mechanisms. In this paper, two different types of binding materials, i.e., fly ash-based geopolymer and ordinary portland cement, were mixed with limestone aggregate to examine and compare the microstructures and nanomechanical properties of interphase region. To …

Flow Patterns Through Vascular Graft Models With And Without Cuffs, Chia Min Leong, Gary B. Nackman, Timothy Wei

Department of Mechanical and Materials Engineering: Faculty Publications

The shape of a bypass graft plays an important role on its efficacy. Here, we investigated flow through two vascular graft designs±with and without cuff at the anastomosis. We conducted Digital Particle Image Velocimetry (DPIV) measurements to obtain the flow field information through these vascular grafts. Two pulsatile flow waveforms corresponding to cardiac cycles during the rest and the excitation states, with 10% and without retrograde flow out the proximal end of the native artery were examined. In the absence of retrograde flow, the straight end-to-side graft showed recirculation and stagnation regions that lasted throughout the full cardiac cycle with …