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Full-Text Articles in Engineering

Synthesis And Characterization Of Functiona Materials For 3d Printed Composites, Elizabeth Irene Reza May 2021

Synthesis And Characterization Of Functiona Materials For 3d Printed Composites, Elizabeth Irene Reza

Open Access Theses & Dissertations

The following body of work encompasses the synThesis, upscaling, additive manufacturing, and characterization of microspheres as functional fillers incorporated into polymer syntactic foams. Synthesizing microspheres permits control over morphology, dispersion of particles, and size while the use of direct write manufacturing allowed for the controllability of filler orientation. Two different syntactic foams were developed from similar methodologies: (1) a silicone syntactic foam (2) epoxy syntactic foam. The silicone epoxy foam showed an increasing in damping and elastic modulus. The epoxy syntactic foams showed an enhanced thermal and electrical properties.


Characterization And Modeling Of Asphalt Concrete For Dynamic Properties And Performances, A S M A. Rahman Dec 2017

Characterization And Modeling Of Asphalt Concrete For Dynamic Properties And Performances, A S M A. Rahman

Civil Engineering ETDs

The recently developed mechanistic-empirical pavement design guide (MEPDG, also known as Pavement M-E design method) uses the nationally calibrated, binder viscosity-based dynamic modulus predictive model for the design and analysis of asphalt pavements. In this study, this model is assessed for its appropriateness for asphalt-aggregate mixtures typically used in New Mexico. In essence, this study investigates the predictability issue of complex modulus of New Mexico mixes. A total of 54 Superpave mixes with different aggregate gradations, air voids, and binder grades were collected from the mixing plants and from the pavement construction sites. The loose asphalt mixtures were then compacted, …


Characterization Of Suspension Polymerized Polyacrylamide And Poly(Sodium Acrylate-Acrylamide) Copolymer And Their Size Influence On The Properties Of Concrete, Cole R. Davis, Kendra A. Erk, Stacey L. Kelly Aug 2016

Characterization Of Suspension Polymerized Polyacrylamide And Poly(Sodium Acrylate-Acrylamide) Copolymer And Their Size Influence On The Properties Of Concrete, Cole R. Davis, Kendra A. Erk, Stacey L. Kelly

The Summer Undergraduate Research Fellowship (SURF) Symposium

Shrinkage leading to cracking and mechanical instability is a major problem for concrete due to the loss of water during the curing process. However, through the addition of Superabsorbent Polymer (SAP) hydrogels, shrinkage can be prevented, increasing the strength of concrete. Characterization of suspension polymerized polyacrylamide (PAM) poly(sodium acrylate-polyacrylamide) (PANa-PAM) copolymer microsphere sizes, morphology and swelling behavior was conducted before adding them to concrete. Size was determined using microscopy paired with ImageJ analysis. Coulter Counter size characterization was also used to determine the particle size distribution. Swelling behavior was determined using the tea bag method as well as size analysis …


Characterization In 2d Sulfides And Graphene Composites For Sensing Applications, Alberto Delgado Jan 2016

Characterization In 2d Sulfides And Graphene Composites For Sensing Applications, Alberto Delgado

Open Access Theses & Dissertations

In this work, we have evaluated 2D layered material composites for opto-electro-mechanical sensing applications. In particular, we have focused on TMDCs and graphite and studied the effects of chemical liquid exfoliation on the structural characteristics of the 2D layered materials, through particle size, x-ray diffraction, Raman and surface area analysis. An approach was developed to combine the solution-processed dispersion with organic and inorganic matrix materials for forming the composites. From Raman Spectroscopy of the ultra-sonicated samples, the I2D/IG>2 for graphite, and for MoS2 the difference between the A1g and E2g peak was 22.85cm-1, consistent with few layer 2D MoS2. …


Growth And Analysis Of Micro And Nano Cdte Arrays For Solar Cell Applications, Brandon Adrian Aguirre Jan 2014

Growth And Analysis Of Micro And Nano Cdte Arrays For Solar Cell Applications, Brandon Adrian Aguirre

Open Access Theses & Dissertations

CdTe is an excellent material for infrared detectors and photovoltaic applications. The efficiency of CdTe/CdS solar cells has increased very rapidly in the last 3 years to ~20% but is still below the maximum theoretical value of 30%. Although the short-circuit current density is close to its maximum of 30 mA/cm2, the open circuit voltage has potential to be increased further to over 1 Volt. The main limitation that prevents further increase in the open-circuit voltage and therefore efficiency is the high defect density in the CdTe absorber layer. Reducing the defect density will increase the open-circuit voltage above 1 …


Nanoprobe I-V Characterization Of Cdte/Cds Micro And Nano-Patterned Solar Cells, Heber Prieto Jan 2012

Nanoprobe I-V Characterization Of Cdte/Cds Micro And Nano-Patterned Solar Cells, Heber Prieto

Open Access Theses & Dissertations

This thesis presents a novel way to characterize micro and nano patterned cadmium telluride thin film solar cells via a nano-probe system. A historical review of CdTe-based solar cells is presented first followed by review of the technology developed to produce the patterned CdTe cells. A detailed presentation is then provided on the use of a Zyvex nanoprobing system to characterize the patterned solar cells. The I-V response of micro- and nano-patterned solar cells stimulated under different e-beam conditions is presented and analyzed. Suggestions of how to improve the technique are provided. This work documents, for the first time, the …


Characterization And Cytotoxic Assessment Of Ballistic Aerosolized Particulates For Tungsten Alloy Penetrators Interacting With Steel Targets, Brenda Ivette Machado Jan 2009

Characterization And Cytotoxic Assessment Of Ballistic Aerosolized Particulates For Tungsten Alloy Penetrators Interacting With Steel Targets, Brenda Ivette Machado

Open Access Theses & Dissertations

The aerosolized particulates produced during an impact of depleted uranium munitions can potentially contaminate extensive areas around the impact sites and cause a wide spectrum of civilian and military damage. Thus materials such as WHA have been prompted for consideration. The present research is concerned with the regular collection of aerosol particulates associated with ballistic WHA rod penetration into rolled homogeneous steel (RHA) or other related steel armor as armor plate sequences. Particulate size characterization via scanning electron microscopy (SEM) and transmission electron microscopy (TEM) along with chemical compositions via energy dispersive spectroscopy (EDS) were the focus of this research. …