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Full-Text Articles in Engineering Science and Materials

Thermal And Orbital Analysis Of Darkness Cubesat, Katie Dickey May 2019

Thermal And Orbital Analysis Of Darkness Cubesat, Katie Dickey

Honors Program Projects

Fermi National Accelerator Laboratory is sending a 3U CubeSat into LEO to search for a 3.5 keV photon corresponding to the decay of a theorized dark matter particle called the sterile neutrino. The CubeSat will encounter environmental variations while in orbit that can be computed through an orbital analysis using System’s Tool Kit. In order to minimize thermal noise readout, improve optical resolution, and increase bandwidth, the sensors must be kept below 170K while taking data. This temperature is difficult to achieve due to radiation from the Sun and the Earth’s albedo radiation. Through the thermal analysis ...


Energy Conversion System For Travelers (Ecost), Thipok Bovornratanaraks Jun 2018

Energy Conversion System For Travelers (Ecost), Thipok Bovornratanaraks

The International Student Science Fair 2018

We have innovated “The Energy Conversion System for Travelers” or the ECoST. With the fact that most travelers have wheeled cabin-bags, whilst walking, the wheels will rotate so why don’t we harvest electricity from this kinetic energy? We thus install our innovation, the ECoST, to the bag to generate electricity from the spinning wheels. The electricity is then kept in the storage unit and ready to charge your empty battery devices in an emergency case via a USB port. To make life easy, our ECoST was designed to replicate the power bank charging method; therefore, we can charge it ...


Precision Radio-Frequency And Microwave Dielectric Spectroscopy And Characterization Of Ionic Aqueous Solutions, Amin Gorji-Bandpy Jan 2018

Precision Radio-Frequency And Microwave Dielectric Spectroscopy And Characterization Of Ionic Aqueous Solutions, Amin Gorji-Bandpy

Graduate Theses and Dissertations

Excessive amounts of chemicals and ions flowing into water sources, which are mainly due to efflux from agricultural lands, cause serious environmental and human-health related concerns. The lack of affordable and real-time monitoring systems for these contaminants limits effective conservation and management strategies. To establish a basis for developing an effective, fast, real-time, and affordable sensing system, dielectric spectroscopy has been applied to characterize agriculturally-relevant aqueous solutions of most commonly found ions in tile drainage water. Dielectric spectra of aqueous sodium chloride (NaCl), sodium nitrate (NaNO3), and sodium sulphate (Na2SO4) ionic solutions, which are the common pollutants found in agricultural ...


Investigating Degradation Pathways In Organic Solar Cell Materials, Satvik Shah Jan 2018

Investigating Degradation Pathways In Organic Solar Cell Materials, Satvik Shah

Graduate Theses and Dissertations

Thin film organic solar is a recent technology with tremendous potential – low cost materials, quicker manufacturing processes and synthetic tuning of organic materials to optimize material properties. Cell efficiencies > 12% have already been achieved. But the bottleneck problem this technology faces is instability. Performance of these cells degrades much faster than traditional solar cells. The degradation occurs on exposure to solar radiation, both through extrinsic ingress of moisture and oxygen as well as intrinsic degradation mechanisms.

One of the most common type of thin film organic cell with efficiency ~10% is PTB7:PCBM organic solar cell. Hence I have tried ...


Inkjet Printing Of Nano-Silver Conductive Ink On Pet Substrate, Skyler Jiang Jun 2017

Inkjet Printing Of Nano-Silver Conductive Ink On Pet Substrate, Skyler Jiang

Materials Engineering

Printing of conductive ink traditionally uses copper-based ink and was used on high temperature metal substrates due to the high curing and sintering temperature of copper. In this experiment, however, Metalon JS-B25P nano-silver conductive ink was printed using an Epson Stylus C88+ inkjet printer on polyethylene terephthalate (PET) based Novele printing media made for low temperature applications. With silver’s lower sintering temperature, the nano-silver particles in this ink are desired to be able to sinter at a low enough temperature to be used on the PET substrate. The printed ink traces were cured with a temperature-controlled hotplate at 100 ...


Flexible, Photopatterned, Colloidal Cdse Semiconductor Nanocrystal Integrated Circuits, Franklin Scott Stinner Jan 2017

Flexible, Photopatterned, Colloidal Cdse Semiconductor Nanocrystal Integrated Circuits, Franklin Scott Stinner

Publicly Accessible Penn Dissertations

As semiconductor manufacturing pushes towards smaller and faster transistors, a parallel goal exists to create transistors which are not nearly as small. These transistors are not intended to match the performance of traditional crystalline semiconductors; they are designed to be significantly lower in cost and manufactured using methods that can make them physically flexible for applications where form is more important than speed. One of the developing technologies for this application is semiconductor nanocrystals.

We first explore methods to develop CdSe nanocrystal semiconducting “inks” into large-scale, high-speed integrated circuits. We demonstrate photopatterned transistors with mobilities of 10 cm2/Vs on ...


Vapor Grown Perovskite Solar Cells, Hisham Abdussamad Abbas Jan 2017

Vapor Grown Perovskite Solar Cells, Hisham Abdussamad Abbas

Graduate Theses and Dissertations

Perovskite solar cells has been the fastest growing solar cell material till date with verified efficiencies of over 22%. Most groups in the world focuses their research on solution based devices that has residual solvent in the material bulk. This work focuses extensively on the fabrication and properties of vapor based perovskite devices that is devoid of solvents.

The initial part of my work focuses on the detailed fabrication of high efficiency consistent sequential vapor NIP devices made using P3HT as P-type Type II heterojunction. The sequential vapor devices experiences device anomalies like voltage evolution and IV hysteresis owing to ...


Dynamic Range Limitations Of Low-Noise Microwave Transistors At Cryogenic Temperatures, Ahmet Hakan Coskun Jan 2017

Dynamic Range Limitations Of Low-Noise Microwave Transistors At Cryogenic Temperatures, Ahmet Hakan Coskun

Doctoral Dissertations

Dynamic range is an important metric that specifies the limits of input signal amplitude for the ideal operation of a given receiver. The low end of dynamic range is defined by the noise floor whereas the upper limit is determined by large-signal distortion. While dynamic range can be predicted in the temperature range where compact transistor models are valid, the lack of large-signal models at temperatures below -55 C prevents the prediction and optimization of dynamic range for applications that require cryogenic cooling. For decades, the main goal concerning the performance of these applications was lowering the noise floor of ...


Structural And Electrical Characterization Of Tin Oxide Resistive Switching, Arka Talukdar Jan 2017

Structural And Electrical Characterization Of Tin Oxide Resistive Switching, Arka Talukdar

Open Access Theses & Dissertations

Resistive switching in metal oxide is a phenomenon in which the metal oxide changes its resistance upon application of electric field and thus giving two states; high resistance state (HRS) and low resistance state (LRS). Many metal oxides have been investigated however very little is known about unipolar resistive switching in SnO2 though it has shown excellent resistive switching characteristics. Defects in the material play a vital role in resistive switching of the metal oxides. In this work, the role of defects in resistive switching of SnO2 are investigated in Ti/SnO2/Au structures. Two methods were used to control ...


Organic-Inorganic Graphite And Transition Metal Dichalcogenide Based Composites For 3d Printing, Jorge Alfredo Catalan Gonzalez Jan 2017

Organic-Inorganic Graphite And Transition Metal Dichalcogenide Based Composites For 3d Printing, Jorge Alfredo Catalan Gonzalez

Open Access Theses & Dissertations

This project was multipronged to help fuse together topics of additive manufacturing and two-dimensional (2D) layered materials, and studying the mechanical and electrical properties of the composites produced. The composites are made from the thermoplastic polymer acting as a matrix and the graphite and 2D transition metal dichalcogenides (TMDs) serving as the filler or reinforcement. Different concentrations of TMD's were added to the matrix to study the effect of composition on the mechanical and electrical properties. To shed insights into the mechanical properties, test coupons were produced as "dog bone" structures for tensile testing using the ASTM D638 type ...


Investigation Of Electrical Defects Arising From Excessive Sidewall Force And Excessive Tensile Strain On Power Cables, Darren Mcconnon, Joseph Kearney, Tom Looby, James O'Shaughnessy Jan 2017

Investigation Of Electrical Defects Arising From Excessive Sidewall Force And Excessive Tensile Strain On Power Cables, Darren Mcconnon, Joseph Kearney, Tom Looby, James O'Shaughnessy

Conference papers

The study includes a comprehensive review of the existing literature and guidelines regarding the effects of sidewall force and tensile strain on power cables during installation. The most appropriate diagnostic test methods required to analyse these effects are also assessed. The results of tests and analysis of the existing literature are then combined in an attempt to determine a realistic basis for guidelines and recommendations relevant to cable installation forces.


Novel Biomarker Assays Based On Photothermal Effects And Nanophotonics, Yunfei Zhao Jan 2017

Novel Biomarker Assays Based On Photothermal Effects And Nanophotonics, Yunfei Zhao

Graduate Theses and Dissertations

The early diagnosis of some chronic and severe diseases such as cancer, tuberculosis, etc. has been a long-sought goal of the medicine community. Traditional diagnostic tools such as X-ray and fecal blood tests cannot detect the disease before the focus or tumor have grown to an appreciable size or before the number of pathogens or tumor cells has reached a considerable amount in body fluids. These drawbacks could significantly delay the diagnosis. To detect and diagnose such diseases at an early stage, people have sought to detect the biomarkers related to certain physical conditions so that the anomalies caused by ...


Microwave Impedance Microscopy Of Nanostructured Carbon, Timothy Scott Jones Jan 2016

Microwave Impedance Microscopy Of Nanostructured Carbon, Timothy Scott Jones

Publicly Accessible Penn Dissertations

Microwave impedance microscopy (MIM) is a scanning probe technique that measures local changes in tip-sample admittance. The imaginary part of the reported change is calibrated with finite element simulations and physical measurements of a standard capacitive sample, and thereafter the output ∆Y is given a reference value in siemens. Simulations also provide a means of extracting sample conductivity and permittivity from admittance, a procedure verified by comparing the estimated permittivity of polytetrafluoroethlyene (PTFE) to the accepted value. Finally, the well-known effective medium approximation of Bruggeman is considered as a means of estimating the volume fractions of the constituents in inhomogeneous ...


Organic Solar Cells: Degradation Processes And Approaches To Enhance Performance, Fadzai Fungura Jan 2016

Organic Solar Cells: Degradation Processes And Approaches To Enhance Performance, Fadzai Fungura

Graduate Theses and Dissertations

Organic solar cells (OSCs) have attracted a lot of attention due to their potential as flexible, lightweight, and low-cost renewable energy sources. Significant improvements have been made in increasing the devices’ power conversion efficiency (PCE) and extensive efforts to understand degradation mechanisms and increase OSCs’ lifetimes are ongoing. OSCs with higher than 10% efficiency have been reported. Enhanced stability and efficiency of inverted poly(3-hexylthiophene) (P3HT) solar cells with Cesium (Cs) halides were achieved by spin-coating Bphen (4,7-di(phenyl)-1,10-phenanthroline) on the halide layer and adding an ~100nm polystyrene beads layer on the blank side of the OSC ...


Integrated Solar Technologies With Outdoor Pedestrian Bridge Superstructure Decking, Richard K. Racz Mr., Richard Racz Jan 2016

Integrated Solar Technologies With Outdoor Pedestrian Bridge Superstructure Decking, Richard K. Racz Mr., Richard Racz

Masters Theses

Solar technology has been a major topic in sustainable design for many years. In the last five years, however, the solar technology industry has seen a rapid growth in installations and technological advances in cell design. Combined with a rapidly declining overall system cost, the idea of introducing solar technology into a wider range of applications is becoming a focus for engineers and scientists around the world. So many variables which alter solar energy production, such as the sun and surrounding environment, determine whether a solar design is beneficial. This thesis presents a bridge deck surface integrated with solar cells ...


Understanding The Photostability Of Perovskite Solar Cell, Pranav Hemanta Joshi Jan 2016

Understanding The Photostability Of Perovskite Solar Cell, Pranav Hemanta Joshi

Graduate Theses and Dissertations

Global climate change and increasing energy demands have led to a greater focus on cheaper photovoltaic energy solutions. Perovskite solar cells and organic solar cells have emerged as promising technologies for alternative cheaper photovoltaics.

Perovskite solar cells have shown unprecedentedly rapid improvement in power conversion efficiency, from 3% in 2009 to more than 21% today. High absorption coefficient, long diffusion lengths, low exciton binding energy, low defect density and easy of fabrication has made perovskites near ideal material for economical and efficient photovoltaics.

However, stability of perovskite and organic solar cells, especially photostability is still not well understood. In this ...


Synthesis, Device Fabrication, And Characterization Of Two-Dimensional Molybdenum Disulfide, Gustavo Alberto Lara Saenz Jan 2016

Synthesis, Device Fabrication, And Characterization Of Two-Dimensional Molybdenum Disulfide, Gustavo Alberto Lara Saenz

Open Access Theses & Dissertations

The miniaturization of electronic devices according to Moore's Law has been propelled by the continuous demand for faster and smaller devices which continue to advance technology. One recent contribution to this trend was the isolation and characterization of one atom thick of graphite, known as graphene, which led to the Nobel Prize in physics in 2010 being awarded to Andre Geim and Konstantin Novoselov. Graphene and its related nanocarbon derivatives have exceptional mechanical, thermal, optical and electronic properties, making them a potential candidate for electronics and optoelectronics applications. However, this material has no intrinsic bandgap and complicated processes are ...


Experimental And Theoretical Investigations Of Charge Generation And Transport In Thin Film Photovoltaics, Ryan Scott Gebhardt Jan 2016

Experimental And Theoretical Investigations Of Charge Generation And Transport In Thin Film Photovoltaics, Ryan Scott Gebhardt

Graduate Theses and Dissertations

With concerns regarding climate change, pollution, and a limited supply of fossil fuels, photovoltaics are an attractive alternate energy source. Within the field of photovoltaics, thin film organic solar cells are alluring due to their potential low cost, mechanical flexibility, and ease of fabrication. However, there are many drawbacks that need to be overcome such as incomplete photon absorption, incomplete exciton dissociation, and carrier recombination. Three distinct projects addressing charge generation and collection in thin film photovoltaics are described.

The first details the use of microlens arrays (MLAs) as a nonintrusive method to increase photon absorption in organic solar cells ...


Electromechanics Of An Ocean Current Turbine, Vasileios Tzelepis Dec 2015

Electromechanics Of An Ocean Current Turbine, Vasileios Tzelepis

University of New Orleans Theses and Dissertations

The development of a numeric simulation for predicting the performance of an Ocean Current Energy Conversion System is presented in this thesis along with a control system development using a PID controller for the achievement of specified rotational velocity set-points. In the beginning, this numeric model is implemented in MATLAB/Simulink® and it is used to predict the performance of a three phase squirrel single-cage type induction motor/generator in two different cases. The first case is a small 3 meter rotor diameter, 20 kW ocean current turbine with fixed pitch blades, and the second case a 20 meter, 720 ...


Crystal-Amorphous Transformation Via Defect-Templating In Phase-Change Materials, Pavan Nukala Jan 2015

Crystal-Amorphous Transformation Via Defect-Templating In Phase-Change Materials, Pavan Nukala

Publicly Accessible Penn Dissertations

Phase-change materials (PCM) such as GeTe and Ge-Sb-Te alloys are potential candidates for non-volatile memory applications, because they can reversibly and rapidly transform between a crystalline phase and an amorphous phase with medium-range order. Traditionally, crystal-amorphous transformation in these materials has been carried out via melt-quench pathway, where the crystalline phase is heated beyond its melting point by the rising edge of an electric pulse, and the melt phase is quenched by the falling edge into a glassy phase. Formation of an intermediate melt phase in this transformation pathway requires usage of large switching current densities, resulting in energy wastage ...


Ruo2 Nanorods As An Electrocatalyst For Proton Exchange Membrane Water Electrolysis, Richard Smith Jan 2015

Ruo2 Nanorods As An Electrocatalyst For Proton Exchange Membrane Water Electrolysis, Richard Smith

Graduate College Dissertations and Theses

The desire for pure diatomic hydrogen gas, H2(g), has been on the rise since the concept of the hydrogen economy system was proposed back in 1970. The production of hydrogen has been extensively examined over 40 + years as the need to replace current fuel sources, hydrocarbons, has become more prevalent. Currently there are only two practical and renewable production methods of hydrogen; landfill gas and power to gas. This study focuses on the later method; using various renewable energy sources, such as photovoltaics, to provide off-peak energy to perform water electrolysis. Efficient electrolysis takes place in electrochemical cells which ...


Detection Of Sub-Surface Stresses In Ferromagnetic Materials Using A New Barkhausen Noise Method, Orfeas Kypris Jan 2015

Detection Of Sub-Surface Stresses In Ferromagnetic Materials Using A New Barkhausen Noise Method, Orfeas Kypris

Graduate Theses and Dissertations

In this work, a new, non-destructive method for obtaining stress-depth gradients in ferromagnetic structures was developed, using the information contained within magnetic Barkhausen emissions. A depth- and stress-dependent model for the frequency spectrum of Barkhausen emissions was derived and fitted to measured data obtained from steel samples with controlled stress-depth gradients. To achieve this, a library of signal processing and optimization algorithms was developed, which allowed the analysis of large datasets. To validate experimental procedures, a number of solid mechanics finite element simulations were carried out. Proof of concept is demonstrated by assuming linear stress-depth gradients and successfully calculating the ...


Uv Laser-Assisted Diamond Deposition, Mengxiao Wang Nov 2014

Uv Laser-Assisted Diamond Deposition, Mengxiao Wang

Theses, Dissertations, and Student Research from Electrical & Computer Engineering

Diamond, due to its unique properties, has been studied for decades. Many diamond synthesis methods have been developed as well. As one of the synthesis methods, combustion flame chemical vapor deposition (CVD) is considered as the most flexible way. Combined with laser irradiation, laser-assisted combustion flame CVD can enhance the deposition process of diamond films. In this thesis work, efforts were made to explore the capability of a laser-assisted combustion flame CVD technique with krypton fluoride (KrF) excimer laser irradiation for improving diamond thin film quality and deposition rate. The research efforts mainly focus on following activities, including: 1) studying ...


Synthesis, Fabrication And Characterization Of Magnetic And Dielectric Nanoparticles And Nanocomposite Films, Xiaohua Liu Oct 2014

Synthesis, Fabrication And Characterization Of Magnetic And Dielectric Nanoparticles And Nanocomposite Films, Xiaohua Liu

All Dissertations, Theses, and Capstone Projects

Materials science is an interdisciplinary field investigating the structure-property relationship in solid-state materials scientifically and technologically. Nanoscience is concerned with the distinctive properties that matter exhibits when confined to physical dimensions on the order of 10-9 meters. At these length scales, behaviors of particles or elaborate structures are often governed by the rules of quantum mechanics in addition to the physical properties associated with the bulk material.

The work reported here seeks to employ nanocystals, binary nanocomposites and thin films of materials, to build versatile, functional systems and devices. With a focus on dielectric, ferroelectric, and magnetoelectric performance, a ...


Dynamic Characterization Of A Soft Elastomeric Capacitor For Structural Health Monitoring Applications, Husaam Saleem, Simon Laflamme, Filippo Ubertini Mar 2014

Dynamic Characterization Of A Soft Elastomeric Capacitor For Structural Health Monitoring Applications, Husaam Saleem, Simon Laflamme, Filippo Ubertini

Civil, Construction and Environmental Engineering Conference Presentations and Proceedings

A novel thin film sensor consisting of a soft elastomeric capacitor (SEC) for meso-scale monitoring has been developed by the authors. Each SEC transduces surface strain into a measurable change in capacitance. In previous work, the authors have shown that the performance of the SEC compares well with conventional resistive strain gauges, providing a resolution of 25 με using an inexpensive off-the-shelf data acquisition system for capacitance measurements. Here, we further the understanding of the thin film sensor by characterizing its dynamic behavior. The SEC is subjected to dynamic loads in bending mode. The study of Fourier and wavelet transforms ...


Flexible Electronics Based On Solution Processable Organic Semiconductors And Colloidal Semiconductor Nanocrystals, Yuming Lai Jan 2014

Flexible Electronics Based On Solution Processable Organic Semiconductors And Colloidal Semiconductor Nanocrystals, Yuming Lai

Publicly Accessible Penn Dissertations

Solution-processable semiconductors hold great potential for the large-area, low-cost fabrication of flexible electronics. Recent advances in flexible electronics have introduced new functional devices such as light-weight displays and conformal sensors. However, key challenges remain to develop flexible devices from emerging materials that use simple fabrication processes and have high-performance.

In this thesis, we first use a solution-processable organic semiconductor to build field-effect transistors on large-area plastic with mobility of 0.1 cm^2/Vs. Combined with passive components, we are able to build voltage amplifiers to capture few mV amplitude bio-signals. This work provides a proof of concept on applying ...


Resistance Switching Devices Based On Amorphous Insulator-Metal Thin Films, Xiang Yang Jan 2014

Resistance Switching Devices Based On Amorphous Insulator-Metal Thin Films, Xiang Yang

Publicly Accessible Penn Dissertations

Nanometallic resistance switching devices based on amorphous insulator-metal thin films are developed to provide a novel non-volatile resistance-switching random-access memory (RRAM) that is CMOS-compatible and meeting technological demand. In these devices, data recording/converting is controlled by a bipolar voltage, which tunes electron localization lengths, hence resistivity, through electron trapping and detrapping. The low-resistance state is a metallic state while the high-resistance state is an insulating state, as established by conductivity studies from 2K to 300K.

The material is exemplified by a Si3N4 thin film with randomly dispersed Pt or Cr. It has been extended to other ...


Designing Nanomaterials For Electronic And Optoelectronic Devices Through Charge Carrier Control, Soong Ju Oh Jan 2014

Designing Nanomaterials For Electronic And Optoelectronic Devices Through Charge Carrier Control, Soong Ju Oh

Publicly Accessible Penn Dissertations

Colloidal semiconductor nanocrystals (NCs) have been shown to be promising materials for electronic and optoelectronic device applications because of their unique size-dependent properties and low-cost solution processability. However, the integration of these materials into devices has been challenging due to a lack of available methods to: 1) accurately control charge carrier statistics, such as majority carrier type and concentration, and carrier mobilities, and 2) efficiently passivate surface defects inherent in NC materials arising from their high surface-volume ratio.

In this thesis, we study the fundamental physics of charge carriers paramount for device application. Then, we introduce several measurement techniques to ...


Evaluating Thermal Imaging For Identification And Characterization Of Solar Cell Defects, Jiahao Chen Jan 2014

Evaluating Thermal Imaging For Identification And Characterization Of Solar Cell Defects, Jiahao Chen

Graduate Theses and Dissertations

Solar cells have become a primary technology in today's world for harvesting clean and renewable energy. Progress has been made towards improving the performance and quality of solar cells and reducing the cost. Both industry and researchers have done a lot of work in designing the solar cell structures, finding better materials for fabricating solar cells and studying the physics of solar cells. However, there remain challenges in fabrication and materials that degrade the performance of solar cells, one of which is the existence of shunts. Shunts have been broadly studied and are known to be common defects in ...


Magnetic Hysteresis And Barkhausen Noise Emission Analysis Of Magnetic Materials And Composites, Neelam Prabhu Gaunkar Jan 2014

Magnetic Hysteresis And Barkhausen Noise Emission Analysis Of Magnetic Materials And Composites, Neelam Prabhu Gaunkar

Graduate Theses and Dissertations

Barkhausen emission studies have been used to analyze the effect of residual stresses in ferromagnetic materials. The stresses generated due to mechanical wear and tear, abrasion and prolonged use can also lead to phase changes within the material. These phase changes can cause damage to the structural parts and should be prevented. In this study we analyze the magnetic hysteresis and Barkhausen noise profile of materials with more than one ferromagnetic phase. The correlation between the hysteresis and Barkhausen noise profiles for such materials is studied. Secondary Barkhausen emission peaks can be simulated for such materials. Experimental observations are compared ...