Nanoscience and Nanotechnology Commons^™

Mechanical Characteristics Of Cement Paste In The Presence Of Carbon Nanotubes And Silica Oxide Nanoparticles: An Experimental Study, Moses Karakouzian, Visar Farhangi, Marzieh R. Farani, Alireza Joshaghani, Mehdi Zadehmohamad, Mohammad Ahmadzadeh

Civil and Environmental Engineering and Construction Faculty Research

Considering the remarkable characteristics of nanomaterials, previous research studies investigated the effects of incorporating different types of these materials on improving the concrete properties. However, further studies are required to evaluate the complementary hybridization and synergistic influence of nanomaterials. In this research, the combined effect of adding nano silica particles (NS) and multi-walled carbon nanotubes (MWCNT) on enhancing both the compressive and flexural strengths of the cement paste was investigated. Moreover, the morphology of the interface between cement paste and aggregates was studied by scanning electron microscopy (SEM). The mixtures were prepared using three different portions of MWCNT and NS. …

Buckling Of Blue Phosphorus Nanotubes Under Axial Compression: Insights From Molecular Dynamics Simulations, Shiping Jiang, Huiling Wu, Liangzhi Kou, Chun Tang, Chengyuan Wang, Changfeng Chen

Physics & Astronomy Faculty Research

We report on mechanical properties of blue phosphorus nanotubes (BluePNTs) from systematic molecular dynamics simulations, adopting a Stillinger-Weber potential with parameters determined by fitting to energetic and structural data from first-principles calculations. Our results corroborate the previously reported bending poison effect and size-dependent buckling behaviors. Under axial compression, current simulations predict a shell-to-column buckling mode transition for BluePNTs with increasing aspect ratios; further compression of BluePNTs with large aspect ratios results in a column-to-shell buckling mode transition. Associated critical buckling strains can be described by the continuum mechanics theory. We also simulated buckling behavior of black phosphorus nanotubes (BlackPNTs) and …

Lanthanum Halide Nanoparticle Scintillators For Nuclear Radiation Detection, Paul Guss, Ronald Guise, Ding Yuan, Sanjoy Mukhopadhyay, Robert O’Brien, Daniel Robert Lowe, Zhitao Kang, Hisham Menkara, Vivek V. Nagarkar

Mechanical Engineering Faculty Research

Nanoparticles with sizesscintillators, in order to determine the viability of using scintillators employing nanostructured lanthanum trifluoride. Preliminary results of this investigation are consistent with the idea that these materials have an intrinsic response to nuclear radiation that may be correlated to the energy of the incident radiation.

Transparent Actuator Made With Few Layer Graphene Electrode And Dielectric Elastomer, For Variable Focus Lens, Taeseon Hwang, Hyeok-Yong Kwon, Joon-Suk Oh, Jung-Pyo Hong, Seung-Chul Hong, Youngkwan Lee, Hyouk Ryeo Choi, Kwang J. Kim, Mainul Hossain Bhuiya, Jae Do Nam

Mechanical Engineering Faculty Research

A transparent dielectric elastomer actuator driven by few-layer-graphene (FLG) electrode was experimentally investigated. The electrodes were made of graphene, which was dispersed inN-methyl-pyrrolidone. The transparent actuator was fabricated from developed FLG electrodes.The FLG electrode with its sheet resistance of 0.45 kΩ/sq (80 nm thick) was implemented to mask silicone elastomer. The developed FLG-driven actuator exhibited an optical transparency of over 57% at a wavenumber of 600 nm and produced bending displacement performance ranging from 29 to 946 μm as functions of frequency and voltage. The focus variation was clearly demonstrated under actuation to study its application-feasibility in …

Streaming Potential Generated By A Pressure-Driven Flow Over Superhydrophobic Stripes, Hui Zhao

Mechanical Engineering Faculty Research

The streaming potential generated by a pressure-driven flow over a weakly charged slip-stick surface [the zeta potential of the surface is smaller than the thermal potential (25 mV)] with an arbitrary double layer thickness is theoretically studied by solving the Debye–Huckel equation and Stokes equation. A series solution of the streaming potential is derived. Approximate expressions for the streaming potential in the limits of thin double layers and thick double layers are also given in excellent agreement with the full solution. To understand the impact of the slip, the streaming potential is compared against that over a homogeneously charged smooth …

On The Effect Of Hydrodynamic Slip On The Polarization Of A Nonconducting Spherical Particle In An Alternating Electric Field, Hui Zhao

Mechanical Engineering Faculty Research

The polarization of a charged, dielectric, spherical particle with a hydrodynamically slipping surface under the influence of a uniform alternating electric field is studied by solving the standard model (the Poisson–Nernst–Planck equations). The dipole moment characterizing the strength of the polarization is computed as a function of the double layer thickness, the electric field frequency, the particle’s surface charge, and the slip length. Our studies reveal that two processes contribute to the dipole moment: ion transport inside the double layer driven by the electric field and the particle’s electrophoretic motion. The hydrodynamic slip will simultaneously impact both processes. In the …

Giant Raman Enhancement On Nanoporous Gold Film By Conjugating With Nanoparticles For Single-Molecule Detection, Lihua Qian, Biswajit Das, Yan Li, Zhilin Yang

Electrical & Computer Engineering Faculty Research

Hot spots have the contradictively geometrical requirements for both the narrowest interstices to provide strong near-field coupling, and sufficient space to allow entrance of the analytes. Herein, a two-step method is employed to create hot spots within hybrid nanostructures, which consist of self-supported nanoporous gold films with the absorbed probes and subsequent nanoparticle conjugates without surface agents or mechanical motion. The molecules confined into 1 nm interstice exhibit 2.9 × 10⁷ times enhancement in Raman scattering compared to pure nanoporous gold. Giant enhancement primarily results from strong near-field coupling between nanopore and nanoparticle, which is theoretically confirmed by finite-difference …

Research On The Transport And Deposition Of Nanoparticles In A Rotating Curved Pipe, Jianzhong Lin, Peifeng Lin, Huajun Chen

Mechanical Engineering Faculty Research

A finite-volume code and the SIMPLE scheme are used to study the transport and deposition of nanoparticles in a rotating curved pipe for different angular velocities, Dean numbers, and Schmidt numbers. The results show that when the Schmidt number is small, the nanoparticle distributions are mostly determined by the axial velocity. When the Schmidt number is many orders of magnitude larger than 1, the secondary flow will dominate the nanoparticle distribution. When the pipe corotates, the distribution of nanoparticle mass fraction is similar to that for the stationary case. There is a “hot spot” deposition region near the outside edge …

An Ultrahigh Vacuum Complementary Metal Oxide Silicon Compatible Nonlithographic System To Fabricate Nanoparticle-Based Devices, Arghya Banerjee, Biswajit Das

Electrical & Computer Engineering Faculty Research

Nanoparticles of metals and semiconductors are promising for the implementation of a variety of photonic and electronic devices with superior performances and new functionalities. However, their successful implementation has been limited due to the lack of appropriate fabrication processes that are suitable for volume manufacturing. The current techniques for the fabrication of nanoparticles either are solution based, thus requiring complex surface passivation, or have severe constraints over the choice of particle size and material. We have developed an ultrahigh vacuum system for the implementation of a complex nanosystem that is flexible and compatible with the silicon integrated circuit process, thus …

Development Of Nanostructure Based Corrosion-Barrier Coatings On Steel For Transmutation Applications, Biswajit Das

Transmutation Sciences Materials (TRP)

Advanced transmutation systems require structural materials that are able to withstand high neutron fluxes, high thermal cycling, and high resistance to chemical corrosion. The current candidate materials for such structures are ferritic and ferritic-martensitic steels due to their strong resistance to swelling, good microstructural stability under irradiation, and the retention of adequate ductility at typical reactor operating temperatures.

In parallel, lead-bismuth eutectic (LBE) has emerged as a potential spallation target material for efficient production of neutrons, as well as a coolant in the accelerator system. While LBE has excellent properties as a nuclear coolant, it is also highly corrosive to …

A New Method Of Synthesizing Black Birnessite Nanoparticles: From Brown To Black Birnessite With Nanostructures, Shizhi Qian, Marcos A. Cheney, Pradip K. Bhowmik, Sang W. Joo, Wensheng Hou, Joseph M. Okoh

Mechanical Engineering Faculty Research

A new method for preparing black birnessite nanoparticles is introduced. The initial synthesis process resembles the classical McKenzie method of preparing brown birnessite except for slower cooling and closing the system from the ambient air. Subsequent process, including wet-aging at 7◦C for 48 hours, overnight freezing, and lyophilization, is shown to convert the brown birnessite into black birnessite with complex nanomorphology with folded sheets and spirals. Characterization of the product is performed by X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), thermogravimetric analysis (TGA), and N2 adsorption (BET) techniques. Wet-aging and lyophilization times are shown to …

Development Of Nanostructure Based Corrosion-Barrier Coatings On Steel For Transmutation Applications, Biswajit Das

Transmutation Sciences Materials (TRP)

Advanced transmutation systems require structural materials that are able to withstand high neutron fluxes, high thermal cycling, and high resistance to chemical corrosion. The current candidate materials for such structures are ferritic and ferritic-martensitic steels due to their strong resistance to swelling, good microstructural stability under irradiation, and the retention of adequate ductility at typical reactor operating temperatures.

In parallel, lead-bismuth eutectic (LBE) has emerged as a potential spallation target material for efficient production of neutrons, as well as a coolant in the accelerator system. While LBE has excellent properties as a nuclear coolant, it is also highly corrosive to …

Modeling Redox-Based Magnetohydrodynamics In Three-Dimensional Microfluidic Channels, Hussameddine S. Kabbani, Aihua Wang, Xiaobing Luo, Shizhi Qian

Mechanical Engineering Faculty Research

RedOx-based magnetohydrodynamic MHD[1] flows in three-dimensional microfluidic channels are investigated theoretically with a coupled mathematical model consisting of the Nernst-Planck equations for the concentrations of ionic species, the local electroneutrality condition for the electric potential, and the Navier-Stokes equations for the flow field. A potential difference is externally applied across two planar electrodes positioned along the opposing walls of a microchannel that is filled with a dilute RedOx electrolyte solution, and a Faradaic current transmitted through the solution results. The entire device is positioned under a magnetic field which can be provided by either a permanent magnet or an electromagnet. …

Corrosion Barrier Development For Lbe Corrosion Resistance: Quarterly Report (April 2006), Biswajit Das

Transmutation Sciences Materials (TRP)

As reported in the last quarterly report, synthesis of Cr nanowires was found to be problematic in terms of uniform coverage. Hence Ni was identified as the alternative metal to form the nanowires. The purpose of the metal nanowires is to provide structural integrity to the nanoporous alumina, as well as a second defense mechanism against corrosion by oxidizing in case the top alumina layer is compromised. Nickel was selected due to its established electrochemical synthesis procedure. While Ni can provide very good structural integrity to the porous alumina, one potential problem is its higher dissolution rate in LBE. However, …

Development Of Nanostructure Based Corrosion-Barrier Coatings On Steel For Transmutation Applications, Biswajit Das

Transmutation Sciences Materials (TRP)

Advanced transmutation systems require structural materials that are able to withstand high neutron fluxes, high thermal cycling, and high resistance to chemical corrosion. The current candidate materials for such structures are ferritic and ferritic-martensitic steels due to their strong resistance to swelling, good microstructural stability under irradiation, and the retention of adequate ductility at typical reactor operating temperatures.

In parallel, lead bismuth eutectic (LBE) has emerged as a potential spallation target material for efficient production of neutrons, as well as a coolant in the accelerator system. While LBE has excellent properties as a nuclear coolant, it is also highly corrosive …

Corrosion Barrier Development For Lbe Corrosion Resistance, Biswajit Das

Transmutation Sciences Materials (TRP)

In the last quarter, a specialized sample holder was developed for the anodization of alumina on steel. In addition, it was determined that oxalic acid was the most appropriate acid for the anodization of these structures. The steel samples obtained from LANL were first cut into a number of pieces, each measuring 11mm x 8mm x 1.6mm, to allow multiple experiments. Special care was taken to ensure that the cutting process did not damage the samples. After investigation of several techniques, including laser cutting, the samples were cut using EDM wires. The cut steel pieces did not show any damage …

Corrosion Barrier Development For Lbe Corrosion Resistance: Quaterly Report, Biswajit Das

Transmutation Sciences Materials (TRP)

With the demonstration of formation of nanoporous alumina on steel and its good adhesion to substrate under thermal cycling, the next project task was to synthesize Chromium nanowires inside the alumina pores. During the previous quarter, a specialized sample holder was developed towards this goal. Various techniques for the deposition of Chromium were investigated and electro-deposition was determined to be the most suitable approach due to the large aspect ratio of the pores. A challenge in using electro-deposition for porous alumina is the potential sealing of the pores in aqueous solutions at higher temperatures. To avoid this problem, a search …

Development Of Nanostructure Based Corrosion-Barrier Coatings On Steel For Transmutation Applications, Biswajit Das

Transmutation Sciences Materials (TRP)

Advanced transmutation systems require structural materials that are able to withstand high neutron fluxes, high thermal cycling, and high resistance to chemical corrosion. The current candidate materials for such structures are ferritic and ferritic-martensitic steels due to their strong resistance to swelling, good microstructural stability under irradiation, and the retention of adequate ductility at typical reactor operating temperatures.

In parallel, lead bismuth eutectic (LBE) has emerged as a potential spallation target material for efficient production of neutrons, as well as a coolant in the accelerator system. While LBE has excellent properties as a nuclear coolant, it is also highly corrosive …

Development Of Nanostructure Based Corrosion-Barrier Coatings On Steel For Transmutation Applications, Biswajit Das

Transmutation Sciences Materials (TRP)

The objective of this project is to develop a novel nanostructure based coating technology that will provide significantly improved corrosion resistance for steel in LBE at elevated temperatures (500 - 600^oC), as well as provide long-term reliability under thermal cycling. The nanostructure based coatings will consist of a layer of nanoporous alumina with the pores filled with an oxidizing metal such as Cr, followed by a capping layer of alumina. Alumina, which is a robust anti-corrosion material, provides corrosion resistance at elevated temperatures. The Cr serves two purposes: (1) it acts as a solid filler material for the …

Development Of Nanostructure Based Corrosion-Barrier Coatings On Steel For Transmutation Applications: Quaterly Report, Biswajit Das

Transmutation Sciences Materials (TRP)

During the past quarter, this project employed one graduate student and two undergraduate student researchers and made the following accomplishments :

• Acquisition of steel samples for experiments

• Design and fabrication of specialized anodization apparatus to accommodate steel samples

• Investigation of adhesiveness of aluminum on steel

• Investigation of effects of anodizing acids on steel to identify most appropriate acid and a suitable barrier material

A Self-Consistent Numerical Method For Simulation Of Quantum Transport In High Electron Mobility Transistor; Part Ii: The Full Quantum Transport, Rahim Khoie

Electrical & Computer Engineering Faculty Research

In Part I of this paper we reported a self-consistent Boltzmann-Schrodinger-Poisson simulator for HEMT in which only electrons in the first subband were assumed to be quantized with their motion restricted to 2 dimensions. In that model, the electrons in the second and higher subbands were treated as bulk system behaving as a 3 dimensional electron gas. In Part II of this paper, we extend our simulator to a self-consistent full-quantum model in which the electrons in the second subband are also treated as quantized 2 dimensional gas. In this model, we consider the electrons in the lowest two subbands …