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Articles 1 - 30 of 442

Full-Text Articles in Nanoscience and Nanotechnology

Effects Of Three Dry Powder Inhalers On Deposition Of Aerosolized Medicine In The Human Oral-Pharyngeal-Laryngeal Regions, Mohammed Ali Sep 2019

Effects Of Three Dry Powder Inhalers On Deposition Of Aerosolized Medicine In The Human Oral-Pharyngeal-Laryngeal Regions, Mohammed Ali

Mohammed Ali

The dry powder inhaler (DPI) is a popular, effective and convenient drug delivery device for inhalation therapy to treat asthma. However, a large quantity (approximately 54%) of inhaled aerosols deposit in the oropharyngeal region. Deposition in this region is undesirable because it provides minimum therapeutic benefits and has adverse localized or systemic side effects. This study reports a method of examining electrostatic charge effects on deposition of three DPI aerosols (Spiriva™ Handihaler, Advair Diskus™, and Pulmicort™ Turbohaler) in a cadaver-based cast of the human oral-pharyngeal-laryngeal (OPL) regions. Experimental aerosols were generated from the three commercially available …

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Quantifying Thermal Boundary Conductance Of 2d–3d Interfaces, Zlatan Aksamija, Cameron J. Foss Feb 2019

Quantifying Thermal Boundary Conductance Of 2d–3d Interfaces, Zlatan Aksamija, Cameron J. Foss

Zlatan Aksamija

Heat dissipation in next-generation electronics based on two-dimensional (2D) materials is a
critical issue in their development and implementation. A potential bottleneck for heat removal in
2D-based devices is the thermal pathway from the 2D layer into its supporting substrate. The choice
of substrate, its composition and structure, can strongly impact the thermal boundary conductance
(TBC). Here we investigate the temperature-dependent TBC of 42 interfaces formed between a
group of six 2D materials and seven crystalline and amorphous substrates. We use first-principles
density functional perturbation theory to calculate the full phonon dispersion of the 2D layers and
substrates and then …

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Impact Of Substrate And Process On The Electrical Performance Of Screen-Printed Nickel Electrodes: Fundamental Mechanism Of Ink Film Roughness, Bilge N. Altay, Jerome Jourdan, Vikram S. Turkani, Hervé Dietsch, Dinesh Maddipatla, Alexandra Pekarovicova, Paul D. Fleming, Massood Atashbar Nov 2018

Impact Of Substrate And Process On The Electrical Performance Of Screen-Printed Nickel Electrodes: Fundamental Mechanism Of Ink Film Roughness, Bilge N. Altay, Jerome Jourdan, Vikram S. Turkani, Hervé Dietsch, Dinesh Maddipatla, Alexandra Pekarovicova, Paul D. Fleming, Massood Atashbar

Bilge Nazli Altay

In recent years, traditional printing methods have been integrated to print flexible electronic devices and circuits. Since process requirements for electronics diff er from those for graphic printing, the fundamentals require rediscovery mainly to optimize manufacturing techniques and to find cost reduction methods without compromising functional performance. In addition, alternative inks need to be formulated to increase the variety of functional inks and to pioneer new product developments. In this report, we investigate a thermoplastic-based nickel ink prototype to print electrodes using a screen-printing process. Process fundamentals are explored, and cost reduction methods are addressed by studying …

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Dynamical Thermal Conductivity Of Suspended Graphene Ribbons In The Hydrodynamic Regime, Zlatan Aksamija, Arnab K. Majee Jul 2018

Dynamical Thermal Conductivity Of Suspended Graphene Ribbons In The Hydrodynamic Regime, Zlatan Aksamija, Arnab K. Majee

Zlatan Aksamija

The steady-state behavior of thermal transport in bulk and nanostructured semiconductors has been widely
studied, both theoretically and experimentally. On the other hand, fast transients and frequency dynamics of
thermal conduction has been given less attention. The frequency response of thermal conductivity has become
more crucial in recent years, especially in light of the constant rise in the clock frequencies in microprocessors
and terahertz sensing applications. Thermal conductivity in response to a time-varying temperature field starts
decaying when the frequency exceeds a cutoff frequency Omega_c, which is related to the inverse of phonon relaxation time τ, on the order of …

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Power Dissipation Of Wse2 Field-Effect Transistors Probed By Low- Frequency Raman Thermometry, Zlatan Aksamija, Cameron J. Foss, Arnab K. Majee, Amin Salehi-Khojin Jun 2018

Power Dissipation Of Wse2 Field-Effect Transistors Probed By Low- Frequency Raman Thermometry, Zlatan Aksamija, Cameron J. Foss, Arnab K. Majee, Amin Salehi-Khojin

Zlatan Aksamija

The ongoing shrinkage in the size of two-dimensional (2D) electronic circuitry results in high power densities during device operation, which could cause a significant temperature rise within 2D channels. One challenge in
Raman thermometry of 2D materials is that the commonly used high-frequency modes do not precisely represent the temperature rise in some 2D materials because of peak broadening and intensity weakening at elevated temperatures. In this work, we show that a low-frequency E2g 2 shear mode can be used to accurately extract temperature and measure thermal boundary conductance (TBC) in backgated tungsten diselenide (WSe2) field-effect transistors, whereas the high-frequency …

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Interfacial Thermal Transport In Monolayer Mos2- And Graphene-Based Devices, Zlatan Aksamija Dec 2017

Interfacial Thermal Transport In Monolayer Mos2- And Graphene-Based Devices, Zlatan Aksamija

Zlatan Aksamija

No abstract provided.

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S41598-017-16744-0.Pdf, Zlatan Aksamija Nov 2017

S41598-017-16744-0.Pdf, Zlatan Aksamija

Zlatan Aksamija

No abstract provided.

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Cobalt-Doped Ceria/Reduced Graphene Oxide Nanocomposite As An Efficient Oxygen Reduction Reaction Catalyst And Supercapacitor Material, Shaikh Parwaiz, Kousik Bhunia, Ashok Kumar Das, Mohammad Mansoob Khan Dr, Debabrata Pradhan Aug 2017

Cobalt-Doped Ceria/Reduced Graphene Oxide Nanocomposite As An Efficient Oxygen Reduction Reaction Catalyst And Supercapacitor Material, Shaikh Parwaiz, Kousik Bhunia, Ashok Kumar Das, Mohammad Mansoob Khan Dr, Debabrata Pradhan

Dr. Mohammad Mansoob Khan

 Design and development of highly active and durable oxygen reduction reaction (ORR) catalyst to replace Pt- and Pt-based materials are present challenges in fuel cell research including direct methanol fuel cells (DMFC). The methanol crossover and its subsequent oxidation at the cathode is another unwanted issue that reduces the efficiency of DMFC. Herein we report cobalt-doped ceria (Co-CeO2) as a promising electrocatalyst with competent ORR kinetics mainly through a four-electron reduction pathway, and it surpasses Pt/C by a great margin in terms of stability and methanol tolerance. The Co-CeO2 nanoparticles of diameter 4–7 nm were uniformly …

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Interfacial Thermal Transport In Monolayer Mos2- And Graphene-Based Devices, Zlatan Aksamija, Amin Salehi-Khojin, Cameron J. Foss, Arnab K. Majee, Fatemeh Khalili-Araghi Jul 2017

Interfacial Thermal Transport In Monolayer Mos2- And Graphene-Based Devices, Zlatan Aksamija, Amin Salehi-Khojin, Cameron J. Foss, Arnab K. Majee, Fatemeh Khalili-Araghi

Zlatan Aksamija

In many device architectures based on 2D materials, a major part of the heat generated in hot-spots dissipates in the through-plane direction where the interfacial thermal resistances can significantly restrain the heat removal
capability of the device. Despite its importance, there is an enormous (1–2 orders of magnitude) disagreement in the literature on the interfacial thermal transport characteristics of MoS2 and other transition metal dichalcogenides (TMDs) (0.1–14 MW m−2 K−1). In this report, the thermal boundary conductance (TBC) across MoS2 and graphene monolayers with SiO2/Si and sapphire substrates is systematically investigated using a
custom-made electrical thermometry platform followed by 3D …

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Progress Towards Terahertz Acoustic Phonon Generation In Doping Superlattices, Thomas E. Wilson Mar 2017

Progress Towards Terahertz Acoustic Phonon Generation In Doping Superlattices, Thomas E. Wilson

Thomas E. Wilson

Progress is described in experiments to generate coherent terahertz acoustic phonons in silicon doping superlattices by the resonant absorption of nanosecond-pulsed far-infrared laser radiation. Future experiments are proposed that would use the superlattice as a transducer in a terahertz cryogenic acoustic reflection microscope with sub-nanometer resolution.

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Impact Of Mismatch Angle On Electronic Transport Across Grain Boundaries And Interfaces In 2d Materials, Zlatan Aksamija Dec 2016

Impact Of Mismatch Angle On Electronic Transport Across Grain Boundaries And Interfaces In 2d Materials, Zlatan Aksamija

Zlatan Aksamija

We study the impact of grain boundaries (GB) and misorientation angles between grains on electronic
transport in 2-dimensional materials. Here we have developed a numerical model based on the firstprinciples
electronic bandstructure calculations in conjunction with a method which computes electron
transmission coefficients from simultaneous conservation of energy and momentum at the interface to
essentially evaluate GB/interface resistance in a Landauer formalism. We find that the resistance across
graphene GBs vary over a wide range depending on misorientation angles and type of GBs, starting
from 53 Ω μm for low-mismatch angles in twin (symmetric) GBs to about 1020 Ω μm …

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Exploring Public Values Implications Of The I-Corps Program, Jan Youtie, Philip Shapira Oct 2016

Exploring Public Values Implications Of The I-Corps Program, Jan Youtie, Philip Shapira

Philip Shapira

This paper examines how the concept of public values can be operationalized in an ongoing public initiative to stimulate innovation in an emerging technology. Our study focuses on Innovation Corps (I-Corps)—a program initiated in 2011 by the National Science Foundation (NSF) to accelerate the process of commercializing science-driven discoveries. The I-Corps method has since spread rapidly across multiple US agencies. Separately, there has also been heightened attention to the early anticipation and mitigation of the implications of emerging science and technology. Drawing on the case of nanotechnology, the paper considers how public values related to nanotechnology commercialization can be integrated …

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Analysis Of Corrosion-Induced Diffusion Layer In Zk60a Magnesium Alloy.Pdf, Shumin Li Oct 2016

Analysis Of Corrosion-Induced Diffusion Layer In Zk60a Magnesium Alloy.Pdf, Shumin Li

Shumin Li

Corrosion-induced damage in ZK60A magnesium alloy is analyzed via chemo-mechanical tests. A certain “diffusion” corrosion layer (DCL) is identified, where partial corrosion takes place. This layer is different from the corrosion product layer (CPL). Nanoindentation analysis shows that corrosion modifies mechanical properties in the DCL, which extends up to 8–9 micrometers into the bulk, away from the CPL. Measurements over the DCL indicate a lower elastic modulus and lower fracture toughness compared with the bulk, as well as higher variance (heterogeneity). Elemental analysis confirms the layer is composed of partially oxidized magnesium and diffused chloride ions. Gradual changes in mechanical …

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Hydrogel Microphones For Stealthy Underwater Listening.Pdf, Shumin Li Aug 2016

Hydrogel Microphones For Stealthy Underwater Listening.Pdf, Shumin Li

Shumin Li

No abstract provided.

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Balancing Research And Funding Using Value Of Information And Portfolio Tools For Nanomaterial Risk Classification Jan 2016

Balancing Research And Funding Using Value Of Information And Portfolio Tools For Nanomaterial Risk Classification

Jeffrey Keisler

Risk research for nanomaterials is currently prioritized by means of expert workshops and other deliberative processes. However, analytical techniques that quantify and compare alternative research investments are increasingly recommended. Here, we apply value of information and portfolio decision analysis—methods commonly applied in financial and operations management—to prioritize risk research for multiwalled carbon nanotubes and nanoparticulate silver and titanium dioxide. We modify the widely accepted CB Nanotool hazard evaluation framework, which combines nano- and bulk-material properties into a hazard score, to operate probabilistically with uncertain inputs. Literature is reviewed to develop uncertain estimates for each input parameter, and a Monte Carlo …

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Ferroelectric Polymer Nanopillars Arrays On Flexible Substrates By.Pdf, Shumin Li Dec 2015

Ferroelectric Polymer Nanopillars Arrays On Flexible Substrates By.Pdf, Shumin Li

Shumin Li

No abstract provided.

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Smart Ink For Flexo - 1, Bilge N. Altay Dec 2015

Smart Ink For Flexo - 1, Bilge N. Altay

Bilge Nazli Altay

No abstract provided.

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Shot Noise Thermometry For Thermal Characterization Of Templated Carbon Nanotubes, Robert A. Sayer, Sunkook Kim, Aaron D. Franklin, Saeed Mohammadi, Timothy Fisher Dec 2015

Shot Noise Thermometry For Thermal Characterization Of Templated Carbon Nanotubes, Robert A. Sayer, Sunkook Kim, Aaron D. Franklin, Saeed Mohammadi, Timothy Fisher

Robert A Sayer

A carbon nanotube (CNT) thermometer that operates on the principles of electrical shot noise is reported. Shot noise thermometry is a self-calibrating measurement technique that relates statistical fluctuations in dc current across a device to temperature. A structure consisting of vertical, top, and bottom-contacted single-walled carbon nanotubes in a porous anodic alumina template was fabricated and used to measure shot noise. Frequencies between 60 and 100 kHz were observed to preclude significant influence from 1/f noise, which does not contain thermally relevant information. Because isothermal models do not accurately reproduce the observed noise trends, a self-heating shot noise model has …

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The Effect Of Frictional And Adhesion Forces Attributed To Slurry Particles On The Surface Quality Of Polished Copper, Yi-Koan Hong, Ja-Hyung Han, Tae-Gon Kim, Jin-Goo Park, Ahmed A. Busnaina Dec 2015

The Effect Of Frictional And Adhesion Forces Attributed To Slurry Particles On The Surface Quality Of Polished Copper, Yi-Koan Hong, Ja-Hyung Han, Tae-Gon Kim, Jin-Goo Park, Ahmed A. Busnaina

Ahmed A. Busnaina

The effect of frictional and adhesion forces attributed to slurry particles on the quality of copper surfaces was experimentally investigated during copper chemical mechanical planarization process. The highest frictional force of 9 Kgf and adhesion force of 5.83 nN were observed in a deionized water-based alumina slurry. On the other hand, the smallest frictional force of 4 Kgf and adhesion force of 0.38 nN were measured in an alumina slurry containing citric acid. However, frictional (6 Kgf) and adhesion (1 nN) forces of silica particles in the slurry were not significantly changed regardless of the addition of citric acid. These …

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The Effect Of Frictional And Adhesion Forces Attributed To Slurry Particles On The Surface Quality Of Polished Copper, Yi-Koan Hong, Ja-Hyung Han, Tae-Gon Kim, Jin-Goo Park, Ahmed A. Busnaina Dec 2015

The Effect Of Frictional And Adhesion Forces Attributed To Slurry Particles On The Surface Quality Of Polished Copper, Yi-Koan Hong, Ja-Hyung Han, Tae-Gon Kim, Jin-Goo Park, Ahmed A. Busnaina

Ahmed A. Busnaina

The effect of frictional and adhesion forces attributed to slurry particles on the quality of copper surfaces was experimentally investigated during copper chemical mechanical planarization process. The highest frictional force of 9 Kgf and adhesion force of 5.83 nN were observed in a deionized water-based alumina slurry. On the other hand, the smallest frictional force of 4 Kgf and adhesion force of 0.38 nN were measured in an alumina slurry containing citric acid. However, frictional (6 Kgf) and adhesion (1 nN) forces of silica particles in the slurry were not significantly changed regardless of the addition of citric acid. These …

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Spectrally-Selective All-Inorganic Scattering Luminophores For Solar Energy-Harvesting Clear Glass Windows, Ramzy Alghamedi, Mikhail Vasiliev, Mohammad Alam, Kamal Alameh Jul 2015

Spectrally-Selective All-Inorganic Scattering Luminophores For Solar Energy-Harvesting Clear Glass Windows, Ramzy Alghamedi, Mikhail Vasiliev, Mohammad Alam, Kamal Alameh

Mikhail Vasiliev

All-inorganic visibly-transparent energy-harvesting clear laminated glass windows are the most practical solution to boosting building-integrated photovoltaics (BIPV) energy outputs significantly while reducing cooling- and heating-related energy consumption in buildings. By incorporating luminophore materials into lamination interlayers and using spectrally-selective thin-film coatings in conjunction with CuInSe2 solar cells, most of the visible solar radiation can be transmitted through the glass window with minimum attenuation while ultraviolet (UV) radiation is down-converted and routed together with a significant part of infrared radiation to the edges for collection by solar cells. Experimental results demonstrate a 10 cm × 10 cm vertically-placed energy-harvesting clear glass …

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Unidirectional Spaser In Symmetry-Broken Plasmonic Core-Shell Nanocavity, Xiangeng Meng, Urcan Guler, Alexander V. Kildishev, Koji Fujita, Katsuhisa Tanaka, Vladimir M. Shalaev Jul 2015

Unidirectional Spaser In Symmetry-Broken Plasmonic Core-Shell Nanocavity, Xiangeng Meng, Urcan Guler, Alexander V. Kildishev, Koji Fujita, Katsuhisa Tanaka, Vladimir M. Shalaev

U. Guler

The spaser, a quantum amplifier of surface plasmons by stimulated emission of radiation, is recognized as a coherent light source capable of confining optical fields at subwavelength scale. The control over the directionality of spasing has not been addressed so far, especially for a single-particle spasing nanocavity where optical feedback is solely provided by a plasmon resonance. In this work we numerically examine an asymmetric spaser - a resonant system comprising a dielectric core capped by a metal semishell. The proposed spaser emits unidirectionally along the axis of the semishell; this directionality depends neither on the incident polarization nor on …

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Nanonickel Catalyst Reinforced With Silicate For Methane Decomposition To Produce Hydrogen And Nanocarbon: Synthesis By Co-Precipitation Cum Modified Stöber Method, Upm Ashik, Wma Wan Daud May 2015

Nanonickel Catalyst Reinforced With Silicate For Methane Decomposition To Produce Hydrogen And Nanocarbon: Synthesis By Co-Precipitation Cum Modified Stöber Method, Upm Ashik, Wma Wan Daud

upm ashik

Co-precipitation cum modified Stöber method is a continuous process avoiding application of higher temperature treatment before supporting nanometal with SiO2, irrespective of pre-preparation methods. We have conducted the co-precipitation process without undertaking calcination under air in order to avoid even a partial particle agglomeration and hence maintained average particle size [similar]30 nm after enforcing with SiO2. This is the first report adopting such an unceasing preparation for preparing metal/silicate nanostructures. Furthermore, n-Ni/SiO2 nanostructured catalysts were used for thermocatalytic decomposition of methane to produce hydrogen and carbon nanotubes. The catalyst was found to be very stable and the methane transformation activity …

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Nanoparticle Plasmonics: Going Practical With Transition Metal Nitrides, U. Guler, V. M. Shalaev, A. Boltasseva Apr 2015

Nanoparticle Plasmonics: Going Practical With Transition Metal Nitrides, U. Guler, V. M. Shalaev, A. Boltasseva

U. Guler

Promising designs and experimental realizations of devices with unusual properties in the field of plasmonics have attracted a great deal of attention over the past few decades. However, the high expectations for realized technology products have not been met so far. The main complication is the absence of robust, high performance, low cost plasmonic materials that can be easily integrated into already established technologies such as microelectronics. This review provides a brief discussion on alternative plasmonic materials for localized surface plasmon applications and focuses on transition metal nitrides, in particular, titanium nitride, which has recently been shown to be a …

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Optical Down-Conversion In Doped Znse:Tb3+ Nanocrystals, Sandip Das, K. C. Mandal Apr 2015

Optical Down-Conversion In Doped Znse:Tb3+ Nanocrystals, Sandip Das, K. C. Mandal

Krishna C. Mandal

No abstract provided.

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Optical Down-Conversion In Doped Znse:Tb3+ Nanocrystals, Sandip Das, K. C. Mandal Apr 2015

Optical Down-Conversion In Doped Znse:Tb3+ Nanocrystals, Sandip Das, K. C. Mandal

Krishna C. Mandal

No abstract provided.

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Tunable Integrated-Optics Nanoscaled Devices Based On Magnetic Photonic Crystals, Mikhail Vasiliev, Vladimir I. Belotelov, Kamal Alameh, R Jeffery, V A. Kotov, A K. Zvezdin Apr 2015

Tunable Integrated-Optics Nanoscaled Devices Based On Magnetic Photonic Crystals, Mikhail Vasiliev, Vladimir I. Belotelov, Kamal Alameh, R Jeffery, V A. Kotov, A K. Zvezdin

Mikhail Vasiliev

Magnetooptical properties of magnetic photonic crystals have been investigated in the view of their possible applications for the modern integrated-optics devices. A "transfer matrices" formalism was expanded for the case of oblique light incidence on the periodic nanoscaled magnetic multilayered systems. Several new effects such as the Faraday effect dependence on the incidence angle and the tunability of the bandgap defect modes spectral location by external magnetic fields were found. Several possibilities of one-dimensional magnetic photonic crystals applications for the optical devices are discussed. Initial steps towards the practical implementation of the proposed devices are reported.

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Nanostructured Engineered Materials With High Magneto-Optic Performance For Integrated Photonics Applications, Mikhail Vasiliev, Kamal Alameh, Viatcheslav A. Kotov, Y T. Lee Apr 2015

Nanostructured Engineered Materials With High Magneto-Optic Performance For Integrated Photonics Applications, Mikhail Vasiliev, Kamal Alameh, Viatcheslav A. Kotov, Y T. Lee

Mikhail Vasiliev

In this paper, we experimentally investigate the performance of a set of technologies used for the deposition, annealing and characterization of high-performance magnetooptic rare-earth-doped garnet materials and all-garnet heterostructures for use in photonic crystals and novel integrated-optics devices.

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Tunable Integrated-Optics Nanoscaled Devices Based On Magnetic Photonic Crystals, Mikhail Vasiliev, Vladimir I. Belotelov, Kamal Alameh, R Jeffery, V A. Kotov, A K. Zvezdin Apr 2015

Tunable Integrated-Optics Nanoscaled Devices Based On Magnetic Photonic Crystals, Mikhail Vasiliev, Vladimir I. Belotelov, Kamal Alameh, R Jeffery, V A. Kotov, A K. Zvezdin

Mikhail Vasiliev

Magnetooptical properties of magnetic photonic crystals have been investigated in the view of their possible applications for the modern integrated-optics devices. A "transfer matrices" formalism was expanded for the case of oblique light incidence on the periodic nanoscaled magnetic multilayered systems. Several new effects such as the Faraday effect dependence on the incidence angle and the tunability of the bandgap defect modes spectral location by external magnetic fields were found. Several possibilities of one-dimensional magnetic photonic crystals applications for the optical devices are discussed. Initial steps towards the practical implementation of the proposed devices are reported.

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Nanostructured Engineered Materials With High Magneto-Optic Performance For Integrated Photonics Applications, Mikhail Vasiliev, Kamal Alameh, Viatcheslav A. Kotov, Y T. Lee Apr 2015

Nanostructured Engineered Materials With High Magneto-Optic Performance For Integrated Photonics Applications, Mikhail Vasiliev, Kamal Alameh, Viatcheslav A. Kotov, Y T. Lee

Mikhail Vasiliev

In this paper, we experimentally investigate the performance of a set of technologies used for the deposition, annealing and characterization of high-performance magnetooptic rare-earth-doped garnet materials and all-garnet heterostructures for use in photonic crystals and novel integrated-optics devices.

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