Materials Science and Engineering Commons^™

Functional Porous Polydimethlysiloxane As Piezoresistive And Piezoelectric Materials, Taissa Rose Michel

Theses and Dissertations

In this paper, polydimethylsiloxane (PDMS), carbon nanotubes (CNTs), and zinc oxide (ZnO) were combined to create functionalized piezoresistive and piezoelectric sensors for pressure sensing and energy harvesting. Samples were foamed to show that the increased deformability of the foam sensors makes them suitable for a range of applications including dexterous robotics, tactile sensing, energy harvesting, and biosensing. Uniform dispersion of CNTs was achieved with chloroform as the solvent. Samples were foamed using chemical blowing and scaffolding but granulated sugar at 70% porosity resulted in foamed samples with the most consistent mechanical properties. Samples underwent tensile and compressive testing for their …

Thermal Interface Material, Matthew Collins Weisenberger, John Davis Craddock

Center for Applied Energy Research Faculty Patents

A flexible sheet of aligned carbon nanotubes includes an array of aligned nanotubes in a free standing film form not adhered to the synthesis substrate, with a matrix infiltrated interstitially into the nanotube array with access to the nanotube tips from both the top and bottom. That is, the infiltrant is purposely limited from over-filling or coating one or both exterior top and/or bottom surfaces of the array, blocking access to the tips. A typical matrix is a polymer material.

60th Annual Rocky Mountain Conference On Magnetic Resonance

Rocky Mountain Conference on Magnetic Resonance

Final program, abstracts, and information about the 60th annual meeting of the Rocky Mountain Conference on Magnetic Resonance, co-endorsed by the Colorado Section of the American Chemical Society and the Society for Applied Spectroscopy. Held in Denver, Colorado, July 21-25, 2019.

Stress Corrosion Cracking Resistance Of Cold-Sprayed Al 6061 Deposits Using A Newly Developed Test Fixture, Mala M. Sharma, Jeremy Schreiber, Timothy Eden, Victor Champagne

Faculty Journal Articles

The stress corrosion cracking (SCC) response of Al 6061 bulk deposits produced by high-pressure cold spray (HPCS) was investigated and compared to commercial wrought Al 6061-T6 material. Representative tensile coupons were stressed to 25%, 65% and 85% of their respective yield strength and exposed to ASTM B117 salt fog for 90 days. After exposure, the samples were mechanically tested to failure, and subsequently investigated for stress corrosion cracking via optical and scanning electron microscopy with energy-dispersive X-ray spectroscopy (EDS). The results were compared to the wrought Al 6061-T6 properties and correlated with the observed microstructures. Wrought samples showed the initiation …

Non-Conventional Mechanism Of Ferroelectric Fatigue Via Cation Migration, Anton Ievlev, Santosh Kc, Rama Vasudevan, Yunseok Kim, Xiaoli Lu, Marin Alexe, Valentino Cooper, Sergei Kalinin, Olga Ovchinnikova

Faculty Publications

The unique properties of ferroelectric materials enable a plethora of applications, which are hindered by the phenomenon known as ferroelectric fatigue that leads to the degradation of ferroelectric properties with polarization cycling. Multiple microscopic models explaining fatigue have been suggested; however, the chemical origins remain poorly understood. Here, we utilize multimodal chemical imaging that combines atomic force microscopy with time-of-flight secondary mass spectrometry to explore the chemical phenomena associated with fatigue in PbZr0.2Ti0.8O3 (PZT) thin films. Investigations reveal that the degradation of ferroelectric properties is correlated with a local chemical change and migration of electrode ions into the PZT structure. …

Study Of Transition Metal Dichalcogenides Via Linear And Non-Linear Spectroscopy, Christopher E. Stevens

USF Tampa Graduate Theses and Dissertations

Beginning with the discovery of graphene, two-dimensional materials have amassed a strong interest. Like graphene, transition metal dichalcogenides (TMDs) can be coaxed into atomically thin sheets which have some impressive properties. Unlike graphene, TMDs also has a change in their electronic band structure causing an indirect band gap to a direct gap transition in its monolayer form. Additionally, these materials lose their inversion symmetry as a monolayer. These unique properties make TMDs a strong candidate for being used in optoelectronic and valleytronic devices. In order for these devices to be successful, the optical properties of TMDs must be thoroughly understood. …

High Enthalpy Storage Thermoset Network With Giant Stress And Energy Output In Rubbery State And Associated Applications, Jizhou Fan

LSU Doctoral Dissertations

In this study, a new shape memory thermoset network with giant stress and energy output in rubbery state is synthesized and studied firstly since the low output in stress and energy in rubbery state has been a bottleneck for wide-spread applications of thermoset shape memory polymers (SMPs). Traditionally, stress or energy storage in thermoset network is through entropy reduction by mechanical deformation or programming. We here report another mechanism for energy storage, which stores energy primarily through enthalpy increase by stretched bonds during programming. As compared to entropy-driven counterparts, which usually have a stable recovery stress from tenths to several …

Teaching Top-Down Approaches To The Engineering Design Process, Joshua E. Katz, Joshua E. Katz

STAR Program Research Presentations

One of the main focuses of metacognition is to have students think about their learning. By bringing the engineering design process with educational psychology together, it can lead to a society that thinks more in-depth on various topics. The goal of the internship was to utilize and teach top-down educational and instructional objectives. Throughout the project, we followed a modified progression of the System Architecture Methodology to help other interns think in a top-down fashion. The purpose of this procedure is to create and induce new innovative and creative ideas for different projects. As teaching this methodology was tasked, research …

Manipulating Fiber Orientation For The Reduction Of Warpage In Carbon Fiber Composite Sandwich Panels, Landon Burnley, Gabrielle Correia

Materials Engineering

Safran Cabin (Santa Maria, CA), previously known as Zodiac Aerospace, designs and manufactures interior cabin components for private and commercial aircraft. Carbon fiber face sheets have recently been incorporated in their overhead luggage bin assemblies which utilize a composite sandwich panel design, in order to provide additional stiffness to the previous glass fiber sandwich panels. Since the introduction of carbon fiber in these luggage bin panels, Safran has experienced an increase in warpage during manufacturing. When inspected by quality control, the panels are tested mimicking how they are installed in aircraft. If the panels do not meet specifications, the warped …

Investigation Of Fundamental Principles Of Rigid Body Impact Mechanics, Khalid Alluhydan

Mechanical Engineering Research Theses and Dissertations

In impact mechanics, the collision between two or more bodies is a common, yet a very challenging problem. Producing analytical solutions that can predict the post-collision motion of the colliding bodies require consistent modeling of the dynamics of the colliding bodies. This dissertation presents a new method for solving the two and multibody impact problems that can be used to predict the post-collision motion of the colliding bodies. Also, we solve the rigid body collision problem of planar kinematic chains with multiple contacts with external surfaces.

In the first part of this dissertation, we study planar collisions of Balls and …

Effect Of Humic Acid Extracted From Thailand's Leonardite On Rice Growth, B Jomhataikool, K Faungnawakij, S Kuboon, W Kraithong, S Chutipaichit, M Fuji, A Eiad-Ua

Journal of Metals, Materials and Minerals

Humic acid have been successfully extracted from leonardite using base-acid treatment. Humic acid is an essential part of soil. This material, present in good soil, makes available of uptake to the plant and the soil nutrients for improving the physical structure of the soil. To extract humic and fulvic acid, the Leonardite is processed in a strongly basic aqueous solution. To precipitate the humic acid, the solution is adjusted to pH 1 with a mineral acid. Carbon, Oxygen, Nitrogen, Aluminium, Silicon and Potassium were extracted from humic acid in humate form (Humic acid reacted with KOH). Rice grower have expressed …

Investigation Of Dissimilar Joining Ferritic Stainless Steel 430 To Austenitic Stainless Steel 304 By Transient Liquid Phase Bonding Process, H Nasri Nasrabadi, M Kasiri Asgarani, K Amini

Journal of Metals, Materials and Minerals

In this study, dissimilar joining of ferritic stainless steel 430 with austenitic stainless steel 304 with BNi-2 Interlayer was investigated by the joint process of the transient liquid phase under inert gas. The joint process was carried out at a constant temperature of 1120°C and at four storage times of 30, 60, 120 and 180 min. To investigate the microscopic structure of the optical microscope, a scanning electron microscope and an X-ray diffraction spectroscopy were used to investigate the mechanical properties of the microhardness and stretching device. At 120 min of storage, due to the proper penetration of the interlayer …

Structural Integrity Assessment Of Tufted Textile Composite And Its Comparison With Laminated Textile Composite, A Saboktakin, A Ghasemi, H Mohammadi

Journal of Metals, Materials and Minerals

Three dimensional composites have been used in aerospace industry to improve interlaminar strength. This paper evaluates the 3D tufted composites from aspect of their mechanical properties. The tufted composite panel was manufactured based on polyester resin as well as an untufted laminated composite for comparison purposes. Experiments show that specimens with transverse tufting suffer slighter reduction in the tensile strength than longitudinal tufting. The tufted composites are found lower tensile strength compared with laminated composite samples accompanied with slight improvement in the compression strength and high strain rate tensile strength. The experimental results presented in this paper should be valuable …

Thermal Correction Judd-Ofelt Analyze Of Eu3+ Ion Doped Calcium Gadolinium Silicoborate Oxyfluoride Glass, N Wantana, Y Ruangtaweep, J Kaewkhao

Journal of Metals, Materials and Minerals

The Calcium Gadolinium Silicoborate Oxyfluoride glass doped with 1.0 mol% of Eu3+ concentration. (CaGdSiBF:Eu3+) was prepared by a melt quenching technique for study in the absorption and emission properties. Glass absorbed photon in ultraviolet, visible light and near infrared regions. The excitation with 275 nm of Gd3+ show the strongest red emission at 613 nm from 5D0→7F2 transition. The Judd-Ofelt (J-O) intensity parameters are derived from the integrated area under absorption and emission, including the refractive index. The thermal correction was used to improve J-O analysis from an uncertainty of Eu3+ population on the ground state. The spectroscopic results were …

Methyl Methacrylate Magnetic Molecularly Imprinted Polymer For Gluten Determination, D Limthin, K Chattrairat, P Leepheng, S Wisutthipat, P Gansa, A Klamchuen, D Phromyothin

Journal of Metals, Materials and Minerals

The gluten protein is found in some rice and flour. The allergy of gluten, a little bit of gluten in diet cause long-term damage and dangerous to the body. Even tiny amounts of gluten in diet may bring enormous symptoms. The rapid and simple method for gluten detection is molecularly imprinted polymers (MIP) combined with electrochemical analysis. In addition, magnetic molecularly imprinted polymers (MMIP) as known as Fe3O4 magnetic nanoparticles have used in combination with electrochemical measurement as well to improve the sensitivity of detection. In this work, the MMIP was combined with electrochemical technique. The Fe3O4 magnetic nanoparticles were …

Effects Of Sulfur Vulcanization System On Cure Characteristics, Physical Properties And Thermal Aging Of Epoxidized Natural Rubber, A Larpkasemsek, L Raksaksri, S Chuayjuljit, P Chaiwutthinan, A Boonmahitthisud

Journal of Metals, Materials and Minerals

The epoxidized natural rubber (ENR) with 40 mol% epoxidation (ENR-40) was initially prepared via 'in situ' epoxidation of concentrated natural rubber latex with formic acid (1M to isoprene unit) and hydrogen peroxide (0.75 M to isoprene unit) at 50ºC for 8 h. The as-prepared ENR-40 was then cured with three different sulfur vulcanization/curing systems, including conventional (CV), semi-efficiency (semi-EV) and efficiency (EV) systems using tetrabenzylthiuram disulphide (TBzTD) as a non-carcinogenic accelerator on a compression molding machine. The effects of sulfur to accelerator ratio on the cure characteristics, tensile properties (tensile strength, modulus at 300% strain (M300) and elongation at break), …

Investigation On The Tribological Characteristics Of Lubricated Al2o3-Tic (Altic) Surface, S Jitphayomkun, P Dechadilok, D Tungasmita, S Tungasmita

Journal of Metals, Materials and Minerals

Lapping process is one of the most important processes in modern hard disk drive manufacturing. Using lubricant in the lapping process does not only reduce the friction but also transfers heat and captures debris away from the surface contacts. The effects of tribological parameters on the lubricant characteristics and friction regime were investigated, using tribometer. The tribological behaviors of the lubricated alumine-titanium carbide (AlTiC) surface with different types of lubricants were also investigated. The coefficient of friction values of stainless steel ball sliding on the lubricated surface exhibited much lower than dry surface. The variation of normal force and sliding …

Recovery Of Recycled Poly(Ethylene Terephthalate) Via Melt Mixing With Poly(Butylene Succinate) And Ultrafine Wollastonite, P Chaiwutthinan, S Chuayjuljit, A Boonmahitthisud, A Larpkasemsuk

Journal of Metals, Materials and Minerals

Recycled poly(ethylene terephthalate) (R-PET) flakes obtained from postconsumer bottles were melt mixed with poly(butylene succinate) (PBS) or with PBS plus ultrafine wollastonite (2000 mesh) at various compositions on a twin screw extruder, followed by injection molding. The tensile properties, morphology, thermal stability and limiting oxygen index (LOI) of the resulting blends and composites were evaluated. Among the investigated R-PET/PBS blend compositions (20, 30, 40, 50, and 60 wt% PBS), the 60/40 wt% blend exhibited the highest tensile strength and elongation at break, but a lower tensile modulus and thermal stability compared to those of the neat R-PET. This blend was …

Effect Of Carbon Addition On Microstructure And Properties Of Boron-Containing Steel Sintered Under Different Atmospheres, W Koetniyom, P Chantawet, N Tosangthum, M Morakotjinda, T Yotkaew, P Wila, R Tongsri

Journal of Metals, Materials and Minerals

High performance sintered steels can be obtained by simultaneous tailoring microstructural feature and improving sintered density. Although sintered hardening is used to produce sintered components with microstructural features providing high tensile strength and hardness, but the performance is limited by low ductility due to the presence of porosity. Near full density can be achieved by liquid phase forming as a result of boron addition to a sintered steel. A liquid formed due to the eutectic reaction of Fe + Fe2B, spreads to interparticle spaces leading to densification improvement. Carbon is an indispensable element for high strength sintered steels. It plays …

Comparison Of Zno Film Prepared By Spray Pyrolysis And Screen Printing Methods, S Suchat, J Potisart, S Supprakob, G Gitgeatpong, P Prachopchok

Journal of Metals, Materials and Minerals

Zinc oxide (ZnO) thin films were prepared and compared between spray pyrolysis and screen-printing techniques. The obtained thin films from both methods were annealed at 400, 450, 500 and 550°C in the air for 30 min, then characterized by x-ray diffraction, ultraviolet-visible spectroscopy and four-point probes techniques. Optical transmittance spectra of ZnO thin films prepared by spray pyrolysis methods and screen printing methods were transmitted through thin film in the range from 300 nm to 800 nm. The lowest of sheet resistance of thin films from both techniques were found to develop at the same annealing temperature of 400°C with …