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2020

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Articles 151 - 166 of 166

Full-Text Articles in Nanoscience and Nanotechnology

Hydrogel Microphone, Li Tan, Yang Gao, Qin Zhou, Yongmei Chen Jan 2020

Hydrogel Microphone, Li Tan, Yang Gao, Qin Zhou, Yongmei Chen

Department of Mechanical and Materials Engineering: Faculty Publications

A device includes a capacitive sensor having a hydrogel structure that includes a first surface and a second surface. A first electrode is provided at the first surface of the hydrogel structure, the first electrode including a network of conductive nanoparticles extending into the hydrogel structure. A second electrode is provided at the second surface of the hydrogel structure.

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Low Velocity Impact Of Hybrid Stacked Steel Plates, H. Hadidi, R. Q. Feng, M. P. Sealy Jan 2020

Low Velocity Impact Of Hybrid Stacked Steel Plates, H. Hadidi, R. Q. Feng, M. P. Sealy

Department of Mechanical and Materials Engineering: Faculty Publications

Designing and manufacturing high-strength, low-weight parts with enhanced impact resistance is highly sought after in the transportation industry. The most common methods to improve strength-to-weight ratios of impact targets is a composite material composition or a favorable geometric design. An alternative method to improve impact performance is functionally gradient mechanical properties in a single material by hybrid additive stacking. In this study, low-velocity impact tests were conducted on hybrid stacked 1070 steel plates where individual layers were subjected to shot peening (SP) to functionally grade mechanical properties. Hybrid additive stacking refers to secondarily processing preferential layers within a stacked build …

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Challenges In Path Planning Of High Energy Density Beams For Additive Manufacturing, Karunakaran K. P, Seema Negi, Arun Nambolan, Yogesh Patil, Milan Pandya, Sajan Kapil, Dmitriy Trushnikov, Michael P. Sealy, Alain Bernard Jan 2020

Challenges In Path Planning Of High Energy Density Beams For Additive Manufacturing, Karunakaran K. P, Seema Negi, Arun Nambolan, Yogesh Patil, Milan Pandya, Sajan Kapil, Dmitriy Trushnikov, Michael P. Sealy, Alain Bernard

Department of Mechanical and Materials Engineering: Faculty Publications

As there are no cutting forces in High Energy Density (HED) beams like lasers and Electron Beam (EB), their speeds are limited only by their positioning systems. On the other hand, as the entire matrix of the 3D printed part has to be addressed by the thin beam in multiple passes in multiple layers, they have to travel several kilometers in tiny motions. Therefore, the acceleration of the motion system becomes the limiting factor than velocity or precision. The authors have proposed an area-filling strategy for EB to fill the layer with optimal squares to exploit analog and hardware computing. …

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Improvement Of Zno Doping Properties Via Sputtering Process With Gas-Timing Technique, Nattaya Tajina Yossapong Jan 2020

Improvement Of Zno Doping Properties Via Sputtering Process With Gas-Timing Technique, Nattaya Tajina Yossapong

Chulalongkorn University Theses and Dissertations (Chula ETD)

In order to obtain high quality of ZnO thin film on plastic and glass substrate for applying to the production of flexible devices, ZnO thin film was investigated by using LP-ZnO buffer layer and gas-timing technique with RF magnetron sputtering at low or room temperature without heat treatment. Growing ZnO thin film directly on plastic substrate without buffer layer, the result was cracking, cavity and wrinkling film. The first part, the effect of buffer layer was studied by growing homo-buffer layer with low-power on plastic substrate and growing main film with high-power on top of that layer calling 2 step …

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Nanostructured Metal Thin Films As Components Of Composite Membranes For Separations And Catalysis, Michael J. Detisch Jan 2020

Nanostructured Metal Thin Films As Components Of Composite Membranes For Separations And Catalysis, Michael J. Detisch

Theses and Dissertations--Chemical and Materials Engineering

Novel metallic thin film composite membranes are synthesized and evaluated in this work for improved separations and catalysis capabilities. Advances in technology that allow for improved membrane performance in solvent separations are desirable for low molecular weight organic separation applications such as those in pharmaceutical industries. Additionally, the introduction of catalytic materials into membrane systems allow for optimization of complex processes in a single step. By adding a nanostructured metallic thin film to its surface, a polymer membrane may be modified to exhibit these improved properties. Using magnetron sputtering, thin metal films may be deposited on commercially available membranes to …

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Synthesis Of Metal Oxide Surface And Interface Arrays By A Combined Solid-Liquid- Vapor/Vapor-Liquid-Solid Approach, Alexandra J. Riddle Jan 2020

Synthesis Of Metal Oxide Surface And Interface Arrays By A Combined Solid-Liquid- Vapor/Vapor-Liquid-Solid Approach, Alexandra J. Riddle

Theses and Dissertations--Chemistry

This project was motivated by an in situ heating experiment in the transmission electron microscope (TEM) in which gold (Au) nanoparticles were observed to dissolve tin dioxide (SnO2) nanowires (NWs) under vacuum. The explanation for this observation was that the high-temperature and low-pressure environment of the TEM caused the reverse reaction of the well-known vapor-liquid-solid (VLS) method commonly used to grow NWs. In the VLS process, a metal catalyst absorbs reactant vapor until it becomes supersaturated. The precipitation of the NW occurs at the liquid-solid interface, which ceases when there is no longer reactant vapor, and the diameter of the …

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Modification Of The Optical Response Of Alpha Quartz Via The Deposition Of Gold Nanoparticles In Etched Ion Tracks, Maria C. Garcia Toro Jan 2020

Modification Of The Optical Response Of Alpha Quartz Via The Deposition Of Gold Nanoparticles In Etched Ion Tracks, Maria C. Garcia Toro

Doctoral Dissertations

”This study addresses the experimental methods used to develop and characterize plasmonic devices capable of modifying the optical response of alpha quartz via the deposition of gold nanoparticles in etched ion tracks. In the first part of the research, the microstructural characterization of latent and etched ion tracks produced in alpha quartz (α-SiO2) is presented. Single crystals of α-SiO2 were irradiated with two highly energetic ions to different nominal fluences. As expected, the morphology of the resulting ion tracks depends on the energy of the incident ion and their stopping powers within the target material. Subsequent chemical …

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Tem Analysis Of Elo Gan Nanostructures On Stripe-Patterned Gaas Substrate By Movpe, Nattamon Suwannaharn Jan 2020

Tem Analysis Of Elo Gan Nanostructures On Stripe-Patterned Gaas Substrate By Movpe, Nattamon Suwannaharn

Chulalongkorn University Theses and Dissertations (Chula ETD)

Epitaxial lateral overgrown (ELO) GaN with AlGaN intermediate layers was grown on stripe-patterned in [110] direction on GaAs (001) substrate by metal-organic vapor phase epitaxy. The purpose of this work is to study the effects of AlGaN intermediate layers and the growth on stripe-patterned in [110] direction on structural phase transformation and defects formation/annihilation in GaN films by high-resolution X-ray diffraction and transmission electron microscopy. The growth rate of AlGaN, and the incorporation of Al into AlGaN was extremely low. According to transmission electron microscopy images, GaN at the window area directly on the substrate nucleates in the mixed phases …

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Formulation And Validation Of Nanoparticle Controlled Delivery For Chemotherapeutic Drug Products, Shani L. Levit Jan 2020

Formulation And Validation Of Nanoparticle Controlled Delivery For Chemotherapeutic Drug Products, Shani L. Levit

Theses and Dissertations

Taxol, a formulation of paclitaxel (PTX), is one of the most widely used anticancer drugs, particularly for treating recurring ovarian carcinomas following surgery. Clinically, PTX is used in combination with other drugs such as lapatinib (LAP) to increase treatment efficacy. Delivering drug combinations with nanoparticles has the potential to improve chemotherapy outcomes. In this study, we use Flash NanoPrecipitation, a rapid, scalable process to encapsulate weakly hydrophobic drugs (logP in vitro. Encapsulating either PTX or LAP into nanoparticles increases drug potency. When PTX and LAP are co-loaded in the same nanoparticle, they have a synergistic effect that is greater than …

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Classification And Biological Identity Of Complex Nano Shapes, Luca Boselli, Hender Lopez, Wei Zhang, Qi Cai, Valeria A. Giannone, Jingji Li, Alirio Moura, João M. De Araujo, Jennifer Cookman, Valentina Castagnola, Yan Yan, Kenneth A. Dawson Jan 2020

Classification And Biological Identity Of Complex Nano Shapes, Luca Boselli, Hender Lopez, Wei Zhang, Qi Cai, Valeria A. Giannone, Jingji Li, Alirio Moura, João M. De Araujo, Jennifer Cookman, Valentina Castagnola, Yan Yan, Kenneth A. Dawson

Articles

Everywhere in our surroundings we increasingly come in contact with nanostructures that have distinctive complex shape features on a scale comparable to the particle itself. Such shape ensembles can be made by modern nano-synthetic methods and many industrial processes. With the ever growing universe of nanoscale shapes, names such as “nanoflowers” and “nanostars” no longer precisely describe or characterise the distinct nature of the particles. Here we capture and digitise particle shape information on the relevant size scale and create a condensed representation in which the essential shape features can be captured, recognized and correlated. We find the natural emergence …

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Artificial Synthetic Scaffolds For Tissue Engineering Application Emphasizing The Role Of Biophysical Cues, Samerender Nagam Hanumantharao Jan 2020

Artificial Synthetic Scaffolds For Tissue Engineering Application Emphasizing The Role Of Biophysical Cues, Samerender Nagam Hanumantharao

Dissertations, Master's Theses and Master's Reports

The mechanotransduction of cells is the intrinsic ability of cells to convert the mechanical signals provided by the surrounding matrix and other cells into biochemical signals that affect several distinct processes such as tumorigenesis, wound healing, and organ formation. The use of biomaterials as an artificial scaffold for cell attachment, differentiation and proliferation provides a tool to modulate and understand the mechanotransduction pathways, develop better in vitro models and clinical remedies. The effect of topographical cues and stiffness was investigated in fibroblasts using polycaprolactone (PCL)- Polyaniline (PANI) based scaffolds that were fabricated using a self-assembly method and electrospinning. Through this …

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3d Printing Of Iron Oxide Incorporated Polydimethylsiloxane Soft Magnetic Actuator, Rasoul Bayaniahangar Jan 2020

3d Printing Of Iron Oxide Incorporated Polydimethylsiloxane Soft Magnetic Actuator, Rasoul Bayaniahangar

Dissertations, Master's Theses and Master's Reports

Soft actuators have grown to be a topic of great scientific interest recently. As the fabrication of soft actuators with conventional microfabrication methods are tedious, expensive, and time consuming, employment of 3-D printing fabrication methods appears promising as they can simplify fabrication and reduce the production cost. Complex structures can be fabricated with 3-D printing such as helical coils can achieve actuation performances that otherwise would not be possible with simpler geometries. In this thesis development of soft magnetic helical coil actuators of iron-oxide embedded polydimethylsiloxane (PDMS) was achieved with embedded 3-D printing techniques. Composites with three different weight ratios …

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Synthesis Of Ruthenium Bipyridine Conjugated Antibiotic For Fluorescence Lifetime Imaging And Spectroscopy Aided Tracking In Citrus, Ryan Parente Jan 2020

Synthesis Of Ruthenium Bipyridine Conjugated Antibiotic For Fluorescence Lifetime Imaging And Spectroscopy Aided Tracking In Citrus, Ryan Parente

Electronic Theses and Dissertations, 2020-2023

Antibiotic treatment of systemic bacterial plant pathogens is an established practice in many crops; however, in citrus it has only recently become available for growers to utilize against Huanglongbing disease. The preliminary efficacy of these treatments is uncertain due to the inability to track their presence in phloem. The need to monitor their movement in planta, especially their presence and translocation in vascular tissue, is a necessary step in clarifying their effectiveness. Previous work has shown the value of Fluorescence Lifetime Imaging (FLIM) in distinguishing between fluorescent probes and plant tissue autofluorescence, which is normally a barrier in photochemical studies …

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Paper-Based Point-Of-Care Tools For Blood Testing, Xuefei Gao Jan 2020

Paper-Based Point-Of-Care Tools For Blood Testing, Xuefei Gao

Graduate Theses, Dissertations, and Problem Reports (ETD)

Early detection of malignant disease is crucial for timely diagnosis and effective medical intervention, which significantly increases survival rates and reduce financial burden on patients. Biomarkers are becoming increasingly important in detection of malignant diseases, because they can be employed for indicating diseases, predicting risks and monitoring the progression of diseases. In addition, biomarkers show up at early stages of diseases in human tissues and fluids (e.g., blood, urine and saliva), which shows great promise for early disease detection. In this dissertation, paper-based lateral flow strips (PLFSs) have been developed for the detection of disease biomarkers, including protein biomarkers and …

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The Synthesis Of Palladium-Platinum Core-Shell Nanoparticles With High Catalytic Peroxidase Activities For Biosensing Applications, Edwin Davidson Jan 2020

The Synthesis Of Palladium-Platinum Core-Shell Nanoparticles With High Catalytic Peroxidase Activities For Biosensing Applications, Edwin Davidson

Electronic Theses and Dissertations, 2020-2023

In recent years, peroxidase mimic nanostructures have attracted special interest due to their low cost, high stability, and high catalytic activity. Herein, we demonstrate the use of Pd-Pt nanocubes (NCs) to achieve the rapid and sensitive colorimetric detection of ascorbic acid (AA), commonly known as vitamin C. The colored signal generated by the catalyzed oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) by the decomposition of hydrogen peroxide (H2O2) is quenched in the presence of AA based on its antioxidant property. This colorimetric method attains a detection limit of 0.40 µM and a linear range from 0 to 15 µM, with good linearity. To …

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Sequence-Coded Coherent Laser Ranging With High Detection Sensitivity, Keren Shemer, Gil Bashan, H Hagai Diamandi, Yosef London, Tzur Raanan, Yochai Israelashvili, Alon Charny, Itzik Cohen, Arik Bergman, Nadav Levanon, Avi Zadok Jan 2020

Sequence-Coded Coherent Laser Ranging With High Detection Sensitivity, Keren Shemer, Gil Bashan, H Hagai Diamandi, Yosef London, Tzur Raanan, Yochai Israelashvili, Alon Charny, Itzik Cohen, Arik Bergman, Nadav Levanon, Avi Zadok

Advanced Science Research Center

The compression of extended, coded sequences allows for laser ranging measurements with low peak power levels. Previous realizations of this approach were restricted by additive noise of direct, incoherent detection. In this work we bring together pulse sequence coding and optical coherent detection to achieve very high sensitivity. Collected sequences with an overall energy equivalent to only 800 photons are successfully compressed. The observed sensitivity agrees with analytic predictions. Compared with incoherent detection, measurement durations are reduced by four orders of magnitude. The protocol is suitable for laser ranging over tens of kilometers, depending on atmospheric conditions.

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