Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 10 of 10
Full-Text Articles in Engineering
Additive Manufacturing Of Binary And Ternary Shape Memory Polyester Blends As A Pathway Towards High Entropy Polymer Systems., Luis Eduardo Lares Carrillo
Additive Manufacturing Of Binary And Ternary Shape Memory Polyester Blends As A Pathway Towards High Entropy Polymer Systems., Luis Eduardo Lares Carrillo
Open Access Theses & Dissertations
The purpose of this work is to incorporate additive manufacturing technology (AM) in the development of shape memory polymer blends. Two polyester blend systems were developed, one binary and the other ternary. The binary blend consisted of polycaprolactone (PCL) and thermoplastic polyurethane (TPU) and the ternary blend was composed of PCL, TPU and polylactic acid (PLA). Test specimens were fabricated with the AM technology of fused filament fabrication (FFF). Several tests were performed to characterize the mechanical and shape memory properties. A dynamic mechanical analyzer (DMA) was first used to establish the shape recovery temperature. Tensile testing was carried out …
Synthesis And Characterization Of Functiona Materials For 3d Printed Composites, Elizabeth Irene Reza
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.
Photovoltage Enhancement For Stable Perovskite Solar Cells With A Temperature-Controlled Grain Growth Technique, Luis Eduardo Valerio
Photovoltage Enhancement For Stable Perovskite Solar Cells With A Temperature-Controlled Grain Growth Technique, Luis Eduardo Valerio
Open Access Theses & Dissertations
By performing strong characterizations methods, one can begin to fully understand the chemistry and composition behind a great performing perovskite solar cell. Understanding how the interaction between layers inside a solar cell is driven by the temperature and overall environment is a key element to improve the fabrication process and overall efficiency of such cells. This Thesis will present a study of the hybrid organic-inorganic, mixed-cation, mixed-halide, temperature and thickness-controlled perovskite solar cell. A constant power conversion efficiency (PCE) ranging between 15-17% and an open circuit voltage V¬oc above 1.05 V for a wide-band gap perovskite cell is presented.
Development And Characterization Of Perovskite Solar Cells For Tandem Device Configuration, Angel Moiseis De La Rosa
Development And Characterization Of Perovskite Solar Cells For Tandem Device Configuration, Angel Moiseis De La Rosa
Open Access Theses & Dissertations
Photovoltaic devices based on perovskite materials are constantly progressing towards more applicability in large-area panels. In order for perovskite-based photovoltaics to reach reliable and stable commercialization, common issues with the use of perovskite still need to be resolved, including the need to identify fabrication processes that can yield optimal material parameters for better photovoltaic performance. Defining an optimal fabrication process requires that researchers and manufacturers alike come to an agreement regarding perovskite characteristics that result from device operation and material processing. This work focuses on characterizing physical, electrical, and electronic properties of a FAxCs1-xPb(IyBr1-y)3 perovskite, and how some of these …
Materials Characterization In The Development Of Combustion-Based Methods For Synthesis Of Niobium Silicides, Edgar Maguregui
Materials Characterization In The Development Of Combustion-Based Methods For Synthesis Of Niobium Silicides, Edgar Maguregui
Open Access Theses & Dissertations
The use of characterization techniques is essential for a better understanding of novel manufacturing processes and for investigating how the process parameters affect the products. Mechanically activated self-propagating high-temperature synthesis (MASHS) is an attractive method for the production of high-temperature structural materials. In the present work, it was used to fabricate Nb5Si3 compound and Nb5Si3/Nb composites. It has been shown that for mechanical activation of Nb/Si mixtures, a planetary ball mill is more effective than a shaker ball mill used in prior research on MASHS of Nb5Si3. The influence of mixture composition and experimental parameters, such as milling time and …
Manufacturing And Characterization Of Energetic Materials, Carlos Alberto Catzin
Manufacturing And Characterization Of Energetic Materials, Carlos Alberto Catzin
Open Access Theses & Dissertations
Few products take several years of research effort to be synthesize yet disintegrate in scarcely millionths of a second when used. Despite their short lifespan energetic materials, particularly high explosives, are in demand as never before by the Aerospace, Defense, Energy, Gas, Mining, and Oil Industry for their unique properties. One class of high explosives known as polymer bonded explosives (PBXs) are popularly used in a wide variety of applications ranging from solid rocket propellants to the main explosive charge in conventional ammunitions. A key characteristic behind the popularity of PBXs in comparison to other high explosives is their handling …
Characterization In 2d Sulfides And Graphene Composites For Sensing Applications, Alberto Delgado
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
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
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
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. …