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Articles 1 - 18 of 18

Full-Text Articles in Nanoscience and Nanotechnology

Novel Nanocomposite Clay Brick For Strain Sensing In Structural Masonry, F. Ubertini, A. D'Alessandro, A. L. Materazzi, Simon Laflamme, Austin Downey Feb 2018

Novel Nanocomposite Clay Brick For Strain Sensing In Structural Masonry, F. Ubertini, A. D'Alessandro, A. L. Materazzi, Simon Laflamme, Austin Downey

Simon Laflamme

The monitoring of civil structures is critical in ensuring users' safety. Structural health monitoring (SHM) is the automation of this monitoring task. It is typically used to identify incipient damages through a spatio-temporal comparison in structural behaviors. Traditional sensors exhibit mechanical characteristics that are usually very different from those of the structures they monitor, which is a factor limiting their durability. Ideally, the material of a sensor would share the same mechanical characteristics as the material onto or into which it is installed. A solution is to fabricate multifunctional materials, capable of serving both structural and sensing functions, also known ...


Continuous And Embedded Solutions For Shm Of Concrete Structures Using Changing Electrical Potential In Self-Sensing Cement-Based Composites, Austin Downey, Enrique Garcia-Macias, Antonella D'Alessandro, Simon Laflamme, Rafael Castro-Triguero, Filippo Ubertini Feb 2018

Continuous And Embedded Solutions For Shm Of Concrete Structures Using Changing Electrical Potential In Self-Sensing Cement-Based Composites, Austin Downey, Enrique Garcia-Macias, Antonella D'Alessandro, Simon Laflamme, Rafael Castro-Triguero, Filippo Ubertini

Simon Laflamme

Interest in the concept of self-sensing structural materials has grown in recent years due to its potential to enable continuous low-cost monitoring of next-generation smart-structures. The development of cement-based smart sensors appears particularly well suited for monitoring applications due to their numerous possible field applications, their ease of use and long-term stability. Additionally, cement-based sensors offer a unique opportunity for structural health monitoring of civil structures because of their compatibility with new or existing infrastructure. Particularly, the addition of conductive carbon nanofillers into a cementitious matrix provides a self-sensing structural material with piezoresistive characteristics sensitive to deformations. The strain-sensing ability ...


Novel Nanocomposite Clay Brick For Strain Sensing In Structural Masonry, F. Ubertini, A. D'Alessandro, A. L. Materazzi, Simon Laflamme, Austin Downey Jul 2017

Novel Nanocomposite Clay Brick For Strain Sensing In Structural Masonry, F. Ubertini, A. D'Alessandro, A. L. Materazzi, Simon Laflamme, Austin Downey

Civil, Construction and Environmental Engineering Conference Presentations and Proceedings

The monitoring of civil structures is critical in ensuring users' safety. Structural health monitoring (SHM) is the automation of this monitoring task. It is typically used to identify incipient damages through a spatio-temporal comparison in structural behaviors. Traditional sensors exhibit mechanical characteristics that are usually very different from those of the structures they monitor, which is a factor limiting their durability. Ideally, the material of a sensor would share the same mechanical characteristics as the material onto or into which it is installed. A solution is to fabricate multifunctional materials, capable of serving both structural and sensing functions, also known ...


Mechanical Characterization Of Polymer Concrete With Nanomaterials, Alaeddin Douba Jun 2017

Mechanical Characterization Of Polymer Concrete With Nanomaterials, Alaeddin Douba

Civil Engineering ETDs

Nanomaterials are defined by those whose characteristic length scale lies within the nanometer scale. Their extreme dimension achieves extraordinary mechanical properties superior to other micro and macro additives. The introduction of nanotechnology to Civil Engineering utilizes low volume inclusions of nanomaterials to alter the properties of conventionally used bulk materials. Polymer Concrete (PC) where epoxy polymer binders replace cement binders, has become a common repair material among many other application and often can be considered an alternative to Portland cement concrete (PCC). PC is often used in bridge deck overlays, manholes, machine foundations and repairs. Its diverse chemical composition and ...


Enhanced Lumped Circuit Model For Smart Nanocomposite Cement-Based Sensors Under Dynamic Compressive Loading Conditions, Enrique García-Macías, Austin Downey, Antonella D’Alessandro, Rafael Castro-Triguero, Simon Laflamme, Filippo Ubertini Jun 2017

Enhanced Lumped Circuit Model For Smart Nanocomposite Cement-Based Sensors Under Dynamic Compressive Loading Conditions, Enrique García-Macías, Austin Downey, Antonella D’Alessandro, Rafael Castro-Triguero, Simon Laflamme, Filippo Ubertini

Civil, Construction and Environmental Engineering Publications

Smart composite nanostructured materials represent one of the fastest-growing areas of interest among scientists in recent years and, in particular, carbon nanotube (CNT) cement-based composites are attracting more and more attention. These composites exhibit self-sensing capabilities providing measurable variations of their electrical properties under the application of mechanical deformations. Together with this exceptional property, the similarity and compatibility between these composites and structural concrete suggest the possibility of developing distributed embedded strain-sensing systems with substantial improvements in the cost-effectiveness in applications to large-scale concrete structures. In order to design and optimize CNT reinforced cement based dynamic sensors, it is fundamental ...


Trihalomethane, Dihaloacetonitrile, And Total N-Nitrosamine Precursor Adsorption By Carbon Nanotubes: The Importance Of Surface Oxides And Pore Volume, Erin Needham May 2017

Trihalomethane, Dihaloacetonitrile, And Total N-Nitrosamine Precursor Adsorption By Carbon Nanotubes: The Importance Of Surface Oxides And Pore Volume, Erin Needham

Theses and Dissertations

As drinking water sources become increasingly impaired, enhanced removal of natural organic matter (NOM) may be required to curb formation of disinfection byproducts (DBPs) upon chlor(am)ination. While carbon nanotubes (CNTs) can adsorb NOM, their properties for DBP precursor adsorption have not been elucidated. Nine types of CNTs were assessed for trihalomethane (THM), dihaloacetonitrile (DHAN), and total N-nitrosamine (TONO) precursor adsorption. Batch isotherm experiments were completed with lake water and, to simulate an impaired condition, effluent from a wastewater treatment plant (WWTP). Adsorption varied with CNT type and dose, with TONO precursors having the highest percent removals from WWTP ...


Total N-Nitrosamine Precursor Adsorption With Carbon Nanotubes: Elucidating Controlling Physiochemical Properties And Developing A Size-Resolved Precursor Surrogate, Erin Needham May 2017

Total N-Nitrosamine Precursor Adsorption With Carbon Nanotubes: Elucidating Controlling Physiochemical Properties And Developing A Size-Resolved Precursor Surrogate, Erin Needham

Theses and Dissertations

As drinking water sources become increasingly impaired with nutrients and wastewater treatment plant (WWTP) effluent, formation of disinfection byproducts (DBPs) – such as trihalomethanes (THMs), dihaloacetonitriles (DHANs), and N-nitrosamines – during water treatment may also increase. N-nitrosamines may comprise the bulk of the chronic toxicity in treated drinking waters despite forming at low ng/L levels. This research seeks to elucidate physicochemical properties of carbon nanotubes (CNTs) for removal of DBP precursors, with an emphasis on total N-nitrosamines (TONO).

Batch experiments with CNTs were completed to assess adsorption of THM, DHAN, and TONO precursors; physiochemical properties of CNTs were quantified through gas ...


Continuous And Embedded Solutions For Shm Of Concrete Structures Using Changing Electrical Potential In Self-Sensing Cement-Based Composites, Austin Downey, Enrique Garcia-Macias, Antonella D'Alessandro, Simon Laflamme, Rafael Castro-Triguero, Filippo Ubertini Apr 2017

Continuous And Embedded Solutions For Shm Of Concrete Structures Using Changing Electrical Potential In Self-Sensing Cement-Based Composites, Austin Downey, Enrique Garcia-Macias, Antonella D'Alessandro, Simon Laflamme, Rafael Castro-Triguero, Filippo Ubertini

Civil, Construction and Environmental Engineering Conference Presentations and Proceedings

Interest in the concept of self-sensing structural materials has grown in recent years due to its potential to enable continuous low-cost monitoring of next-generation smart-structures. The development of cement-based smart sensors appears particularly well suited for monitoring applications due to their numerous possible field applications, their ease of use and long-term stability. Additionally, cement-based sensors offer a unique opportunity for structural health monitoring of civil structures because of their compatibility with new or existing infrastructure. Particularly, the addition of conductive carbon nanofillers into a cementitious matrix provides a self-sensing structural material with piezoresistive characteristics sensitive to deformations. The strain-sensing ability ...


Effect Of Hydration And Confinement On Micro-Structure Of Calcium-Silicate-Hydrate Gels, Harish Kumar Gadde Jan 2017

Effect Of Hydration And Confinement On Micro-Structure Of Calcium-Silicate-Hydrate Gels, Harish Kumar Gadde

Civil Engineering Graduate Theses & Dissertations

Calcium-silicate-hydrate(C-S-H) gel is a primary nano-crystalline phase present in hydrated Ordinary Portland Cement (OPC) responsible for its strength and creep behavior. Our reliance on cement for infrastructure is global, and there is a need to improve infrastructure life-times. A way forward is to engineer the cement with more durability and long-term strength. The main purpose of this research is to quantify the micro-structure of C-S-H to see if cement can be engineered at various length scales to improve long-term behavior by spatial arrangement. We investigate the micro-structure evolution of C-S-H in cement as a function of hydration time and ...


Effect Of Hydration And Confinement On Micro-Structure Of Calcium-Silicate-Hydrate Gels, Harish Kumar Gadde Jan 2017

Effect Of Hydration And Confinement On Micro-Structure Of Calcium-Silicate-Hydrate Gels, Harish Kumar Gadde

Civil Engineering Graduate Theses & Dissertations

Calcium-silicate-hydrate(C-S-H) gel is a primary nano-crystalline phase present in hydrated Ordinary Portland Cement (OPC) responsible for its strength and creep behavior. Our reliance on cement for infrastructure is global, and there is a need to improve infrastructure life-times. A way forward is to engineer the cement with more durability and long-term strength. The main purpose of this research is to quantify the micro-structure of C-S-H to see if cement can be engineered at various length scales to improve long-term behavior by spatial arrangement. We investigate the micro-structure evolution of C-S-H in cement as a function of hydration time and ...


The Experiment And Analysis Of Active Mechanisms For Enhancing Heat And Mass Transfer In Sorption Fluids, Ziqi Shen Jul 2016

The Experiment And Analysis Of Active Mechanisms For Enhancing Heat And Mass Transfer In Sorption Fluids, Ziqi Shen

Architectural Engineering -- Dissertations and Student Research

This project was funded by American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE RP-1462). It is a three years’ research, including the literature review, labs construction, experiments and data analysis.

In this thesis, first of all, we conducted literature review of mechanism motion influence on heat and mass transfer and additive effect in absorption chiller. This part helps us understand the basic idea of how mechanism motion affects the heat and mass transfer of sorption fluids and gives us reference on how to select the experiment instrument and the experiment operation range.

In the second part, the instrument selection ...


Strain Sensitivity Of Carbon Nanotube Cement-Based Composites For Structural Health Monitoring, Antonella D'Alessandro, Filippo Ubertini, Simon Laflamme, Marco Rallini, Josè M. Kenny Apr 2016

Strain Sensitivity Of Carbon Nanotube Cement-Based Composites For Structural Health Monitoring, Antonella D'Alessandro, Filippo Ubertini, Simon Laflamme, Marco Rallini, Josè M. Kenny

Civil, Construction and Environmental Engineering Conference Presentations and Proceedings

Cement-based smart sensors appear particularly suitable for monitoring applications, due to their self-sensing abilities, their ease of use, and their numerous possible field applications. The addition of conductive carbon nanofillers into a cementitious matrix provides the material with piezoresistive characteristics and enhanced sensitivity to mechanical alterations. The strain-sensing ability is achieved by correlating the variation of external loads or deformations with the variation of specific electrical parameters, such as the electrical resistance. Among conductive nanofillers, carbon nanotubes (CNTs) have shown promise for the fabrication of self-monitoring composites. However, some issues related to the filler dispersion and the mix design of ...


Nano-Modification For High Performance Cement Composites With Cellulose Nanocrystals And Carbon Nanotubes, Yizheng Cao Oct 2014

Nano-Modification For High Performance Cement Composites With Cellulose Nanocrystals And Carbon Nanotubes, Yizheng Cao

Open Access Dissertations

One of the new engineering frontiers is the exploration of infrastructure materials with novel combinations of properties that break traditional paradigms. The goal of this study is to utilize two different nano-fibers, cellulose nanocrystals (CNCs) and carbon nanotubes (CNTs) to modify the nanoscale structures of cement composites and thereby improve the performance at the macro-level. This study also evaluates the mechanism behind the modification, since fiber bridging, the most common reinforcing mechanism for fiber-reinforced composites, cannot be simply applied because CNCs are too short to bridge cracks in cement composites. ^ The mechanical tests show an increase in the flexural strength ...


Transport Properties Of Nano-Silica Contained Self-Consolidating Concrete, Borhan Moradi Aug 2014

Transport Properties Of Nano-Silica Contained Self-Consolidating Concrete, Borhan Moradi

UNLV Theses, Dissertations, Professional Papers, and Capstones

In this research study, transport properties of various self-consolidating concretes (SCCs) containing nano-particles (SiO2) were investigated. Nano-silica replaced a portion of the cementitious materials at different replacement levels ranging from 1.5 to 7.5% by weight. For the purpose of this investigation, flow, bulk, and transport properties of SCCs were studied. The investigated transport properties were absorption, water penetration, rapid chloride permeability, capillary absorption, rapid migration, and chloride diffusion. Transport properties of nano-silica SCCs were also compared to those of equivalent silica fume (micro silica) contained concretes, as well as those of control mixture (concrete without nano or micro ...


Selected Durability Studies Of Geopolymer Concrete With Respect To Carbonation, Elevated Temperature, And Microbial Induced Corrosion, Mohammad Sufian Badar Apr 2014

Selected Durability Studies Of Geopolymer Concrete With Respect To Carbonation, Elevated Temperature, And Microbial Induced Corrosion, Mohammad Sufian Badar

Doctoral Dissertations

This thesis reports a comprehensive study related to the experimental evaluation of carbonation in reinforced geopolymer concrete, the evaluation of geopolymer concretes at elevated temperature, and the resistance of geopolymer concrete to microbial induced corrosion (MIC).

Carbonation: Reinforced concretes, made of geopolymer, prepared from two class F fly ashes and one class C fly ash, were subjected to accelerated carbonation treatment for a period of 450 days. Electrochemical, microstructure and pore structure examinations were performed to evaluate the effect of corrosion caused due to carbonation. GPC specimens prepared from class F fly ash exhibited lower corrosion rates by a factor ...


Crystalline Cellulose – Atomistic Modeling Toolkit, Mateo Gomez, Pablo Zavattieri Dr. Oct 2013

Crystalline Cellulose – Atomistic Modeling Toolkit, Mateo Gomez, Pablo Zavattieri Dr.

The Summer Undergraduate Research Fellowship (SURF) Symposium

Nature has created efficient strategies to make materials with hierarchical internal structure that often exhibit exceptional mechanical properties. One such example is found in cellulose, in fact it is eight times stronger than stainless steel and advantage is that cellulose incredibly cheap, because processing is obtained from purified wood pulp (it is environmental friendly). The most prevalent modeling technique to study the fundamental mechanical behavior of the crystalline cellulose has been Molecular Dynamics (MD). As a predictive tool, MD allows us to study the behavior of crystalline cellulose at the atomic level, and as such, it accurately predicts the crystalline ...


Enhanced Polymer Nanocomposites For Condition Assessment Of Wind Turbine Blades, Husaam S. Saleem, M. Thunga, M. Kollosche, Michael R. Kessler, Simon Laflamme Apr 2013

Enhanced Polymer Nanocomposites For Condition Assessment Of Wind Turbine Blades, Husaam S. Saleem, M. Thunga, M. Kollosche, Michael R. Kessler, Simon Laflamme

Civil, Construction and Environmental Engineering Conference Presentations and Proceedings

Damages in composite components of wind turbine blades and large-scale structures can lead to increase in maintenance and repair costs, inoperability, and structural failure. The vast majority of condition assessment of composite structures is conducted by visual inspection and non-destructive evaluation (NDE) techniques. NDE techniques are temporally limited, and may be further impeded by the anisotropy of the composite materials, conductivity of the fibers, and the insulating properties of the matrix. In previous work, the authors have proposed a novel soft elastomeric capacitor (SEC) sensor for monitoring of large surfaces, applicable to composite materials. This soft capacitor is fabricated using ...


Halloysite Clay Nanotubes For Controlled Delivery Of Chemically Active Agents, Elshard Abdullayev Oct 2010

Halloysite Clay Nanotubes For Controlled Delivery Of Chemically Active Agents, Elshard Abdullayev

Doctoral Dissertations

In this work we explored the capabilities of halloysite nanotubes as capsules for encapsulation and controlled delivery of the chemically and biologically active substances. Halloysite is a two-layered aluminosilicate which has a predominantly hollow tubular structure in the submicron range and is chemically similar to kaolinite [1, 2].

In the first section of this work, we analyzed the structure of the halloysite nanotubes as well as its capability to encapsulate and deliver biologically and chemically active agents, similarities and differences between release characteristics of different agents and how these differences relate with their chemical structure. Models were used to describe ...