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Structural And Catalytic Differences In The Effect Of Co And Mo As Promoters For Pt-Based Aqueous Phase Reforming Catalysts, Paul J. Dietrich, Fred G. Sollberger, M. Cem Akatay, Eric A. Stach, W.Nicholas Delgass, Jeffrey T. Miller, Fabio H. Ribeiro 2014 Purdue University

Structural And Catalytic Differences In The Effect Of Co And Mo As Promoters For Pt-Based Aqueous Phase Reforming Catalysts, Paul J. Dietrich, Fred G. Sollberger, M. Cem Akatay, Eric A. Stach, W.Nicholas Delgass, Jeffrey T. Miller, Fabio H. Ribeiro

Birck and NCN Publications

Reaction rates (site time yields, normalized to CO chemisorption sites) and product selectivity were determined for PtCo, PtMo, and Pt supported on multi-walled carbon nanotubes for aqueous phase reforming of glycerol. The bimetallic PtCo and PtMo catalysts had 4.6x and 5.4x higher glycerol consumption rates than Pt, and 3.9x and 0.6x rates in H-2 formation compared to Pt. Hydrogen generation selectivity was similar on Pt and PtCo, but PtMo had an increase in selectivity to C-O cleavage products, which reduced H-2 yield at conversions over 60% (85-90% hydrogen yield for Pt and PtCo, 65% for PtMo ...


Opto-Electronic Devices With Nanoparticles And Their Assemblies, Chieu Van Nguyen 2014 University of Nebraska - Lincoln

Opto-Electronic Devices With Nanoparticles And Their Assemblies, Chieu Van Nguyen

Chemical & Biomolecular Engineering Theses, Dissertations, & Student Research

Nanotechnology is a fast growing field; engineering matters at the nano-meter scale. A key nanomaterial is nanoparticles (NPs). These sub-wavelength (< 100nm) particles provide tremendous possibilities due to their unique electrical, optical, and mechanical properties. Plethora of NPs with various chemical composition, size and shape has been synthesized. Clever designs of sub-wavelength structures enable observation of unusual properties of materials, and have led to new areas of research such as metamaterials. This dissertation describes two self-assemblies of gold nanoparticles, leading to an ultra-soft thin film and multi-functional single electron device at room temperature. First, the layer-by-layer self-assembly of 10nm Au nanoparticles and polyelectrolytes is shown to behave like a cellular-foam with modulus below 100 kPa. As a result, the composite thin film (~ 100nm) is 5 orders of magnitude softer than an equally thin typical polymer film. The thin film can be compressed reversibly to 60% strain. The extraordinarily low modulus and high compressibility are advantageous in pressure sensing applications. The unique mechanical properties of the composite film lead to development of an ultra-sensitive tactile imaging device capable of screening for breast cancer. On par with human finger sensitivity, the tactile device can detect a 5mm imbedded object up to 20mm below the surface with low background noise. The second device is based on a one-dimensional (1-D) self-directed self-assembly of Au NPs mediated by dielectric materials. Depending on the coverage density of the Au NPs assembly deposited on the device, electronic emission was observed at ultra-low bias of 40V, leading to low-power plasma generation in air at atmospheric pressure. Light emitted from the plasma is apparent to the naked eyes. Similarly, 1-D self-assembly of Au NPs mediated by iron oxide was fabricated and exhibits ferro-magnetic behavior. The multi-functional 1-D self-assembly of Au NPs has great potential in modern electronics such as solid state lighting, plasma-based nanoelectronics, and memory devices.

Adviser: Ravi F. Saraf


In-Situ Fluorescent Immunomagnetic Multiplex Detection Of Foodborne Pathogens In Very Low Numbers, Il-Hoon Cho, Lisa Mauer, Joseph Irudayaraj 2014 Purdue University

In-Situ Fluorescent Immunomagnetic Multiplex Detection Of Foodborne Pathogens In Very Low Numbers, Il-Hoon Cho, Lisa Mauer, Joseph Irudayaraj

Birck and NCN Publications

Consumption of foods contaminated with pathogenic bacteria is a major public health concern. Foods contain microorganisms, the overwhelming majority of which are nonpathogenic, some are responsible for food spoilage, and some cause serious illness leading to death or a variety of diseases in humans. The key challenge in food safety is to rapidly screen foods to determine the presence of pathogens so that appropriate intervention protocols can be pursued. A simple fluorometric immunological method in combination with a magnetic concentration step was developed for rapid detection of target bacteria with high sensitivity and specificity in less than 2 h without ...


Surface Topography And Chemistry Shape Cellular Behavior On Wide Band-Gap Semiconductors, Lauren E. Bain, Ramon Collazo, Shu-han Hsu, Nicole Pfiester Latham, Michael J. Manfra, Albena Ivanisevic 2014 Purdue University

Surface Topography And Chemistry Shape Cellular Behavior On Wide Band-Gap Semiconductors, Lauren E. Bain, Ramon Collazo, Shu-Han Hsu, Nicole Pfiester Latham, Michael J. Manfra, Albena Ivanisevic

Birck and NCN Publications

The chemical stability and electrical properties of gallium nitride make it a promising material for the development of biocompatible electronics, a range of devices including biosensors as well as interfaces for probing and controlling cellular growth and signaling. To improve the interface formed between the probe material and the cell or biosystem, surface topography and chemistry can be applied to modify the ways in which the device interacts with its environment. PC12 cells are cultured on as-grown planar, unidirectionally polished, etched nanoporous and nanowire GaN surfaces with and without a physi-sorbed peptide sequence that promotes cell adhesion. While cells demonstrate ...


Technique For Quantitative Mapping Of Three-Dimensional Liquid-Gas Phase Boundaries In Microchannel Flows, Ravi S. Patel, Suresh V. Garimella 2014 Purdue University

Technique For Quantitative Mapping Of Three-Dimensional Liquid-Gas Phase Boundaries In Microchannel Flows, Ravi S. Patel, Suresh V. Garimella

Birck and NCN Publications

A diagnostic technique capable of characterizing interfaces between transparent, immiscible fluids is developed and demonstrated by investigating the morphology of liquid-gas interfaces in an adiabatic two-phase flow through a microchannel of 500 mu m x 500 mu m square cross section. Water seeded with 0.5 mu m-diameter fluorescent polystyrene particles is pumped through the channel, and the desired adiabatic two-phase flow regime is achieved through controlled air injection. The diagnostic technique relies on obtaining particle position data through epifluorescent imaging of the flow at excitation and emission wavelengths of 532 nm and 620 nm, respectively. The particle position data ...


Developent Of A Phospholipid Encapsulation Process For Quantum Dots To Be Used In Biologic Applications, Logan Grimes 2014 California Polytechnic State University

Developent Of A Phospholipid Encapsulation Process For Quantum Dots To Be Used In Biologic Applications, Logan Grimes

Master's Theses and Project Reports

The American Cancer Society predicts that 1,665,540 people will be diagnosed with cancer, and 585,720 people will die from cancer in 2014. One of the most common types of cancer in the United States is skin cancer. Melanoma alone is predicted to account for 10,000 of the cancer related deaths in 2014. As a highly mobile and aggressive form of cancer, melanoma is difficult to fight once it has metastasized through the body. Early detection in such varieties of cancer is critical in improving survival rates in afflicted patients. Present methods of detection rely on visual ...


Nanite Sensor Cube Casing, Morgan Crisp, Robert Izuta, Andrea Zimkowski 2014 California Polytechnic State University

Nanite Sensor Cube Casing, Morgan Crisp, Robert Izuta, Andrea Zimkowski

Mechanical Engineering

Oceanit has developed an innovative weigh-in motion system that uses a new nanomaterial called Nanite, also know as a ‘smart’ concrete, for the load-cell. For the system to function accurately the load-cell must be protected. The Nanite will be molded into 2-inch cubes to be used as the load-cell in the weigh-in motion system. This system will be a cheaper alternative to current weigh-in motion systems, and allow for better-widespread health monitoring of roadways. These sensors will be placed under the roadway and need protection from both the environment and the weight of passing vehicles on the road. Oceanit is ...


Quantum And Classical Magnetoresistance In Ambipolar Topological Insulator Transistors With Gate-Tunable Bulk And Surface Conduction, Jifa Tian, Cuizu Chang, Helin Cao, Ke He, Xucun Ma, Qikun Xue, Yong P. Chen 2014 Purdue University

Quantum And Classical Magnetoresistance In Ambipolar Topological Insulator Transistors With Gate-Tunable Bulk And Surface Conduction, Jifa Tian, Cuizu Chang, Helin Cao, Ke He, Xucun Ma, Qikun Xue, Yong P. Chen

Birck and NCN Publications

Weak antilocalization (WAL) and linear magnetoresistance (LMR) are two most commonly observed magnetoresistance (MR) phenomena in topological insulators (TIs) and often attributed to the Dirac topological surface states (TSS). However, ambiguities exist because these phenomena could also come from bulk states (often carrying significant conduction in many TIs) and are observable even in non-TI materials. Here, we demonstrate back-gated ambipolar TI field-effect transistors in (Bi0.04Sb0.96)(2)Te-3 thin films grown by molecular beam epitaxy on SrTiO3(111), exhibiting a large carrier density tunability (by nearly 2 orders of magnitude) and a metal-insulator transition in the bulk (allowing switching ...


Non-Volatile Switching Of Magnetism In Multiferroic Heterostructures, Tianxiang Nan 2014 Northeastern University

Non-Volatile Switching Of Magnetism In Multiferroic Heterostructures, Tianxiang Nan

Electrical and Computer Engineering Master's Theses

Multiferroic materials and devices have attracted intensified interests due to the demonstrated strong magnetoelectric coupling in new multiferroic materials, artificial multiferroic heterostructures and devices with unique functionalities and superior performance characteristics. This offers great opportunities for achieving compact, fast, energy-efficient and voltage tunable spintronic devices. In traditional magnetic materials based magnetic random access memories (MRAM) devices, the binary information is stored as magnetization. The high coercivity of the ferromagnetic media requires large magnetic fields for switching the magnetic states thus consuming large amount of energy. In modern MRAM information writing process, spin-torque technique is utilized for minimizing the large energy ...


Role Of Atomic Variability And Mechanical Constraints On The Martensitic Phase Transformation Of A Model Disordered Shape Memory Alloy Via Molecular Dynamics, Keith Ryan Morrison, Mathew J. Cherukara, Karthink Guda Vishnu, Alejandro Strachan 2014 Purdue University

Role Of Atomic Variability And Mechanical Constraints On The Martensitic Phase Transformation Of A Model Disordered Shape Memory Alloy Via Molecular Dynamics, Keith Ryan Morrison, Mathew J. Cherukara, Karthink Guda Vishnu, Alejandro Strachan

Birck and NCN Publications

We use molecular dynamics (MD) with an embedded atom model potential parameterized for NiAl to study martensitic phase transformations in a disordered shape memory alloy. We focus on the role of intrinsic atomic-level variability and mechanical constraints on the martensite and austenite transformation temperatures and on the martensite microstructure for specimens with varying size. We find that periodic system size has a weak effect on transformation temperature all the way to the nanometer scale, with the entropy-stabilized austenite phase slightly penalized with decreasing size. Atomic-level variability in these random alloys leads to significant sample-tosample variability in transformation temperature. The uncertainty ...


Unidirectional Amplification And Shaping Of Optical Pulses By Three-Wave Mixing With Negative Phonons, Alexander K. Popov, Mikhail I. Shalaev, Sergey A. Myslivets, Vitaly V. Slabko 2014 Purdue University

Unidirectional Amplification And Shaping Of Optical Pulses By Three-Wave Mixing With Negative Phonons, Alexander K. Popov, Mikhail I. Shalaev, Sergey A. Myslivets, Vitaly V. Slabko

Birck and NCN Publications

A possibility to greatly enhance frequency-conversion efficiency of stimulated Raman scattering is shown by making use of extraordinary properties of three-wave mixing of ordinary and backward waves. Such processes are commonly attributed to negative-index plasmonic metamaterials. This work demonstrates the possibility to replace such metamaterials that are very challenging to engineer by readily available crystals which support elastic waves with contra-directed phase and group velocities. The main goal of this work was to investigate specific properties of indicated nonlinear optical process in short-pulse regime and to show that it enables elimination of fundamental detrimental effect of fast damping of optical ...


Mos2 Field-Effect Transistors With Graphene/Metal Heterocontacts, Yuchen Du, Lingming Yang, Jingyun Zhang, Han Liu, Kausik Majumdar, Paul D. Kirsch, Peide D. Ye 2014 Purdue University

Mos2 Field-Effect Transistors With Graphene/Metal Heterocontacts, Yuchen Du, Lingming Yang, Jingyun Zhang, Han Liu, Kausik Majumdar, Paul D. Kirsch, Peide D. Ye

Birck and NCN Publications

For the first time, n-type few-layer MoS2 field-effect transistors (FETs) with graphene/Ti as the heterocontacts have been fabricated, showing more than 160-mA/mm drain current at 1-mu m gate length with an ON-OFF current ratio of 10(7). The enhanced electrical characteristic is confirmed in a nearly 2.1 times improvement in ON-resistance and a 3.3 times improvement in contact resistance with heterocontacts compared with the MoS2 FETs without graphene contact layer. Temperature-dependent study on MoS2/graphene heterocontacts has been also performed, still unveiling its Schottky contact nature. Transfer length method and a devised I-V method have been ...


Oriented Collagen And Applications Of Waveguide Evanescent Field Scattering (Wefs) Microscopy, Qamrun Nahar 2014 Western University

Oriented Collagen And Applications Of Waveguide Evanescent Field Scattering (Wefs) Microscopy, Qamrun Nahar

University of Western Ontario - Electronic Thesis and Dissertation Repository

In this thesis, Waveguide Evanescent Field Scattering (WEFS) microscopy is developed as a non-invasive, label-free live cell imaging technique. This new high-contrast imaging can be employed to study the first hundred nanometers from the surface as it utilizes the evanescent field of a waveguide as the illumination source. Previously, waveguide evanescent field fluorescence (WEFF) microscopy was developed as a fluorescence imaging technique comparable to the total internal reflection fluorescent (TIRF) microscopy. Both the WEFF and WEFS technique utilizes the same fundamental concepts except in WEFS microscopy imaging is accomplished without the application of any fluorescent labeling. In this work, bacterial ...


Electron Spin Magnetism Of Zigzag Graphene Nanoribbon Edge States, Kun Xu, Peide D. Ye 2014 Purdue University

Electron Spin Magnetism Of Zigzag Graphene Nanoribbon Edge States, Kun Xu, Peide D. Ye

Birck and NCN Publications

The electron spin states of zigzag graphene nanoribbon (ZGNR) edge play a pivotal role in the applications of graphene nanoribbons. However, the exact arrangements of the electron spins remain unclear to date. In this report, the electronic spin states of the ZGNR edge have been elucidated through a combination of quantum chemical investigation and previous electron spin resonance experiment observations. An alternating alpha and beta spin configuration of the unpaired electrons along the ZGNR edge is established in ambient condition without any external magnetic field, and the origin of the spin magnetism of the ZGNR edge is revealed. It paves ...


Refractory Plasmonics, Urcan Guler, Alexandra Boltasseva, Vladimir M. Shalaev 2014 Purdue University

Refractory Plasmonics, Urcan Guler, Alexandra Boltasseva, Vladimir M. Shalaev

Birck and NCN Publications

No abstract provided.


Biogenic Fabrication Of Au@Ceo2 Nanocomposite With Enhanced Visible Light Activity, Mohammad Mansoob Khan Dr, S. A. Ansari, M. O. Ansari, B. K. Min, J Lee, M. H. Cho 2014 SelectedWorks

Biogenic Fabrication Of Au@Ceo2 Nanocomposite With Enhanced Visible Light Activity, Mohammad Mansoob Khan Dr, S. A. Ansari, M. O. Ansari, B. K. Min, J Lee, M. H. Cho

Dr. Mohammad Mansoob Khan

This study reports a biogenic approach to the synthesis of Au@CeO2 nanocomposite using electrochemically active biofilms (EABs) in water under normal pressure and 30 °C. This work presents the results of extensive morphological, structural, optical, visible light photoelectrochemical and photocatalytic studies of Au@CeO2 nanocomposite. The presence of a large number of interfaces between Au nanoparticles and CeO2 for charge transfer is believed to play a key role in enhancing the optical and visible light photoelectrochemical and photocatalytic performance of Au@CeO2 nanocomposite. The enhanced visible light degradation of methyl orange and methylene blue by Au@CeO2 nanocomposite was ...


Observation Of Coulomb Repulsion Between Cu Intercalants In Cuxbi2se3, Chris Mann, Damien West, Ireneusz Miotkowski, Yong P. Chen, Shengbai Zhang, Chih-Kang Shih 2014 Purdue University

Observation Of Coulomb Repulsion Between Cu Intercalants In Cuxbi2se3, Chris Mann, Damien West, Ireneusz Miotkowski, Yong P. Chen, Shengbai Zhang, Chih-Kang Shih

Birck and NCN Publications

Using scanning tunneling microscopy and ab initio simulations, we have identified several configurations for Cu dopants in CuxBi2Se3, with Cu intercalants being the most abundant. Through statistical analysis, we show strong short-range repulsive interactions between Cu intercalants. At intermediate range (>5 nm), the pair distribution function shows oscillatory structure along the < 10 (1) over bar > directions, which appear to be influenced by different diffusion barriers along the < 10 (1) over bar > and < 2 (1) over bar(1) over bar > directions.


Ptsa Doped Conducting Graphene/Polyaniline Nanocomposite Fibers: Thermoelectric Behavior And Electrode Analysis, Mohammad Mansoob Khan Dr, M. O. Ansari, S. A. Ansari, M. I. Amal, J Lee, M. H. Cho 2014 SelectedWorks

Ptsa Doped Conducting Graphene/Polyaniline Nanocomposite Fibers: Thermoelectric Behavior And Electrode Analysis, Mohammad Mansoob Khan Dr, M. O. Ansari, S. A. Ansari, M. I. Amal, J Lee, M. H. Cho

Dr. Mohammad Mansoob Khan

Highly conducting graphene/polyaniline (GN@Pani) nanocomposite was prepared by the in-situ oxidative polymerization of aniline in the presence of GN and the surfactant, cetyltrimethylammonium bromide (CTAB). The micellar structure of CTAB assisted both, the formation of GN@Pani tubules and the dispersion of GN. Sheet-like GN was distributed uniformly in the Pani matrix, leading to high electrical conductivity because of the π-π interactions between Pani and GN. Studies of the thermoelectrical behavior using isothermal and cyclic aging techniques showed that GN@Pani possessed a high combination of electrical conductivity and thermal stability, even beyond 150°C. GN@Pani was ...


Droplet Evaporation On Heated Hydrophobic And Superhydrophobic Surfaces, Susmita Dash, Suresh V. Garimella 2014 Purdue University

Droplet Evaporation On Heated Hydrophobic And Superhydrophobic Surfaces, Susmita Dash, Suresh V. Garimella

Birck and NCN Publications

The evaporation characteristics of sessile water droplets on smooth hydrophobic and structured superhydrophobic heated surfaces are experimentally investigated. Droplets placed on the hierarchical superhydrophobic surface subtend a very high contact angle (similar to 160 degrees) and demonstrate low roll-off angle (similar to 1 degrees), while the hydrophobic substrate supports corresponding values of 120 degrees and similar to 10 degrees. The substrates are heated to different constant temperatures in the range of 40-60 degrees C, which causes the droplet to evaporate much faster than in the case of natural evaporation without heating. The geometric parameters of the droplet, such as contact ...


Variable-Cell Method For Stress-Controlled Jamming Of Athermal, Frictionless Grains, Kyle C. Smith, Ishan Srivastava, Timothy Fisher, Meheboob Alam 2014 Purdue University

Variable-Cell Method For Stress-Controlled Jamming Of Athermal, Frictionless Grains, Kyle C. Smith, Ishan Srivastava, Timothy Fisher, Meheboob Alam

Birck and NCN Publications

A method is introduced to simulate jamming of polyhedral grains under controlled stress that incorporates global degrees of freedom through the metric tensor of a periodic cell containing grains. Jamming under hydrostatic (isotropic) stress and athermal conditions leads to a precise definition of the ideal jamming point at zero shear stress. The structures of tetrahedra jammed hydrostatically exhibit less translational order and lower jamming-point density than previously described maximally random jammed hard tetrahedra. Under the same conditions, cubes jam with negligible nematic order. Grains with octahedral symmetry having s > 0.5 (where s interpolates from octahedra [s = 0] to cubes ...


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