Corrosion Initiation And Propagation On Carburized Martensitic Stainless Steel Surfaces Studied Via Advanced Scanning Probe Microscopy, Armen Kvryan, Corey M. Efaw, Kari A. Higginbotham, Olivia O. Maryon, Paul H. Davis, Elton Graugnard, Michael F. Hurley
Historically, high carbon steels have been used in mechanical applications because their high surface hardness contributes to excellent wear performance. However, in aggressive environments, current bearing steels exhibit insufficient corrosion resistance. Martensitic stainless steels are attractive for bearing applications due to their high corrosion resistance and ability to be surface hardened via carburizing heat treatments. Here three different carburizing heat treatments were applied to UNS S42670: a high-temperature temper (HTT), a low-temperature temper (LTT), and carbo-nitriding (CN). Magnetic force microscopy showed differences in magnetic domains between the matrix and carbides, while scanning Kelvin probe force microscopy (SKPFM) revealed a 90 ...
Phase Transitions And Their Interaction With Dislocations In Silicon, 2019 Iowa State University
Phase Transitions And Their Interaction With Dislocations In Silicon, Valery I. Levitas, Hao Chen, Liming Xiong
Valery I. Levitas
In this paper, phase transformations (PTs) in silicon were investigated through molecular dynamics (MD) using Tersoff potential. In the first step, simulations of PTs in single crystal silicon under various stress-controlled loading were carried out. Results shows that all instability points under various stress states are described by criteria, which are linear in the space of normal stresses. There is a region in the stress space in which conditions for direct and reverse PTs coincide and a unique homogeneous phase transition (without nucleation) can be realized. Finally, phase transition in bi-crystalline silicon with a dislocation pileup along the grain boundary ...
Synthesis And Characterization Of A-Site And B-Site Disordered High-Entropy Perovskites, 2019 University of Tennessee Knoxville
Synthesis And Characterization Of A-Site And B-Site Disordered High-Entropy Perovskites, Quinton Wright
EURēCA: Exhibition of Undergraduate Research and Creative Achievement
Entropy-stabilized oxides are a new class of ceramic material inspired by high-entropy alloys. In entropy-stabilized oxides, many metallic elements in approximately equal amounts occupy one lattice site. The large number of atom types present in the crystal results in a high degree of disorder in the material. The purpose of this study was to determine if a single-phase samples of two entropy-stabilized oxides could be successfully created through solid-state synthesis. The first of these materials - (Gd0.2La0.2Nd0.2Sm0.2Y0.2)MnO3 - has has 5 A-site elements creating a high degree of disorder. The second of these materials - La(Co0 ...
Developing A Method For Testing Tackiness Of Bituminous Tack Coats, 2019 The University of Tennessee
Developing A Method For Testing Tackiness Of Bituminous Tack Coats, Collin M. Pekol Mr.
EURēCA: Exhibition of Undergraduate Research and Creative Achievement
In the construction of roads, asphalt is paved in individual layers. To ensure that these layers behave as a single, cohesive unit, a bituminous tack coat is applied between layers. It is critical that this tack coat is adhesive when the hot mix asphalt is applied and non-adhesive otherwise. As of present, there is no standard method for testing the adhesion of bituminous tack coats. A procedure was developed such that a sample tack coat of ~1 mm thickness was allowed to adhere to a temperature-controlled lower plate. After a set time, the upper geometry was lowered until a set ...
Machine Learning Applications In Computer Integrated Material Design And Modeling, 2019 University of Texas at Tyler
Machine Learning Applications In Computer Integrated Material Design And Modeling, Joseph O. Oyedele
Mechanical Engineering Theses
This research seeks to develop and test a framework for considering Inductive Hierarchical Analysis (IHA) using Machine Learning (ML) technique in a multistage material design of a gear manufacturing process. A ML model was developed, which implements Random Forest (RF) regression algorithm together with analysis of variance (ANOVA) approach for mapping sets of material and product design variables, thus classifying the design space into feasible and non-feasible solution space. This approach is applied to the design of steel gear within specified performance requirements by exploring the design space for the Process-Structure-Property-Performance (PSPP) relation in the hot rolling process. With an ...
The Effect Of Flinak Molten Salt Corrosion On The Hardness Of Hastelloy N, 2019 Olivet Nazarene University
The Effect Of Flinak Molten Salt Corrosion On The Hardness Of Hastelloy N, David Kok
Scholar Week 2016 - present
The Molten Salt Reactor (MSR) has been identified as a promising candidate to replace aging nuclear reactors around the world. However, a suitable combination of molten salt and container material needs to be found in order to reduce the potential for corrosion in the MSR before it can be considered commercially viable. FLiNaK molten salt and the nickel-based alloy Hastelloy N have been identified as prime candidates for this function, but the severity of FLiNaK corrosion in Hastelloy N requires additional study before this combination can be used in the operation of a MSR. In this study, Hastelloy N samples ...
Evaluating The Scalability Of Graphene Synthesis, 2019 Olivet Nazarene University
Evaluating The Scalability Of Graphene Synthesis, Evan Dexter
Scholar Week 2016 - present
Graphene is a new material, first isolated in 2004, consisting of one to a few atomic layers of carbon in a lattice sheet structure. Graphene has high tensile strength, high surface area, very low electrical resistance, and various other special properties that make it an excellent material for use in emerging technologies in the categories of electrical components, energy systems, and high strength applications. The production scale of graphene sheets and its variations is currently limited to laboratory use, with a great amount of current research going into the development of manufacturing techniques of the material. I conducted experiments to ...
X-Ray Determination Of Compressive Residual Stresses In Spring Steel Generated By High-Speed Water Quenching, 2019 Universidad de Monterrey
X-Ray Determination Of Compressive Residual Stresses In Spring Steel Generated By High-Speed Water Quenching, Diego E. Lozano, George E. Totten, Yaneth Bedolla-Gil, Martha Guerrero-Mata, Marcel Carpio, Gabriela M. Martinez-Cazares
Mechanical and Materials Engineering Faculty Publications and Presentations
Automotive components manufacturers use the 5160 steel in leaf and coil springs. The industrial heat treatment process consists in austenitizing followed by the oil quenching and tempering process. Typically, compressive residual stresses are induced by shot peening on the surface of automotive springs to bestow compressive residual stresses that improve the fatigue resistance and increase the service life of the parts after heat treatment. In this work, a high-speed quenching was used to achieve compressive residual stresses on the surface of AISI/SAE 5160 steel samples by producing high thermal gradients and interrupting the cooling in order to generate a ...
Effects Of Disorder On Thermoelectric Properties Of Semiconducting Polymers, 2019 University of Massachusetts - Amherst
Effects Of Disorder On Thermoelectric Properties Of Semiconducting Polymers, Zlatan Aksamija, Dhandapani Venkataraman, Connor J. Boyle, Meenakshi Upadhyaya
Quantifying Bonding Characteristics Between Uhpc And Normal-Strength Concrete For Bridge Deck Application, 2019 University of Alabama - Tuscaloosa
Quantifying Bonding Characteristics Between Uhpc And Normal-Strength Concrete For Bridge Deck Application, Sriram Aaleti, Sri Sritharan
Ultrahigh performance concrete (UHPC) is an advanced cementitious material which has excellent mechanical and durability properties, making it appropriate for the rehabilitation of concrete structures. This paper investigates the usage of a thin layer of UHPC overlaying a normal strength concrete (NC) deck. The behavior of the interface connection will have a significant impact on the overall structural and durability performance of the UHPC-NC composite deck system. An integrated experimental and analytical study was conducted to understand the influence of several variables, such as normal concrete strength, interface roughness, and curing condition on the shear transfer behavior across the interface ...
Surface-Controlled Dissolution Rates: A Case Study Of Nanoceria In Carboxylic Acid Solutions, 2019 University of Kentucky
Surface-Controlled Dissolution Rates: A Case Study Of Nanoceria In Carboxylic Acid Solutions, Eric A. Grulke, Matthew J. Beck, Robert A. Yokel, Jason M. Unrine, Uschi M. Graham, Matthew L. Hancock
Chemical and Materials Engineering Faculty Publications
Nanoparticle dissolution in local milieu can affect their ecotoxicity and therapeutic applications. For example, carboxylic acid release from plant roots can solubilize nanoceria in the rhizosphere, affecting cerium uptake in plants. Nanoparticle dispersions were dialyzed against ten carboxylic acid solutions for up to 30 weeks; the membrane passed cerium-ligand complexes but not nanoceria. Dispersion and solution samples were analyzed for cerium by inductively coupled plasma mass spectrometry (ICP-MS). Particle size and shape distributions were measured by transmission electron microscopy (TEM). Nanoceria dissolved in all carboxylic acid solutions, leading to cascades of progressively smaller nanoparticles and producing soluble products. The dissolution ...
Surrogate Modeling Of Ultrasonic Nondestructive Evaluation Simulations, 2019 Iowa State University
Surrogate Modeling Of Ultrasonic Nondestructive Evaluation Simulations, Jacob Siegler, Leifur Leifsson, Robert Grandin, Slawomir Koziel, Adrian Bekasiewicz
Ultrasonic testing (UT) is used to detect internal flaws in materials or to characterize material properties. Computational simulations are an important part of the UT process. Fast models are essential for UT applications such as inverse design or model-assisted probability of detection. This paper presents investigations of using surrogate modeling techniques to create fast approximate models of UT simulator responses. In particular, we propose to use data-driven surrogate modeling techniques (kriging interpolation), and physics-based surrogate modeling techniques (space mapping), as well a mixture of the two approaches. These techniques are investigated for two cases involving UT simulations of metal components ...
Comparison Of Organic Food Packaging In Denmark, Finland, Germany, Great Britain And Italy, 2019 VTT Technical Research Institute of Finland Ltd
Comparison Of Organic Food Packaging In Denmark, Finland, Germany, Great Britain And Italy, Sara Paunonen, Marja Pitkänen, Mika Vähä-Nissi, Ville Leminen, Mika Kainusalmi
Journal of Applied Packaging Research
The objective of this study was to provide a snapshot of organic food assortments in supermarkets in Denmark, Finland, Germany, Great Britain, and Italy, and compare the packages used for five organic food products (eggs, meat, fish, mushrooms, berries). In addition, a comparison was made between packaging for regular and organic whole eggs. The highest number of organic products was found in the Danish supermarket. The main difference between the countries was in the use of national organic logos. Of the different food products, egg cartons had the most variation in materials and visual design. In all countries the product ...
Green Synthesis Nanocomposite Membranes, 2019 University of Kentucky
Green Synthesis Nanocomposite Membranes, Dibakar Bhattacharyya, Vasile Smuleac, Rajender S. Varma, Subhas K. Sikdar
Chemical and Materials Engineering Faculty Patents
A nanocomposite membrane includes a macroporous polymer membrane having a plurality of pores. A plurality of metal nanoparticles are synthesized and immobilized within those plurality of pores. The nanoparticles are reduced and capped with a green reducing and capping agent such as green tea extract.
A Smart Bandage Equipped With Miniaturized Needle Arrays And Wirelessly-Controlled Drug Delivery System For The Treatment Of Chronic Wounds, 2019 University of Nebraska-Lincoln
A Smart Bandage Equipped With Miniaturized Needle Arrays And Wirelessly-Controlled Drug Delivery System For The Treatment Of Chronic Wounds, Hossein Derakhshandeh
Mechanical (and Materials) Engineering -- Dissertations, Theses, and Student Research
Chronic wounds are one of the most challenging complications of diabetes and are the leading cause of non-traumatic limb amputation. Despite the progress in identifying factors and promising in vitro results for the treatment of chronic wounds, their clinical translation has been limited. Given the range of disruptive processes necessary for wound healing, different pharmacological agents are needed at different stages of tissue regeneration. This requires the capability of wearable devices to deliver agents to critical layers of the epidermis with minimum invasiveness. Here, for the first time, I have engineered a programmable platform which is capable of actively delivering ...
Plasmonic Metamaterials: Physical Background And Some Technological Applications, 2019 Liberty University
Plasmonic Metamaterials: Physical Background And Some Technological Applications, Benjamin G. Schmidt
Senior Honors Theses
New technological frontiers appear every year, and few are as intriguing as the field of plasmonic metamaterials (PMMs). These uniquely designed materials use coherent electron oscillations to accomplish an astonishing array of tasks, and they present diverse opportunities in many scientific fields.
This paper consists of an explanation of the scientific background of PMMs and some technological applications of these fascinating materials. The physics section addresses the foundational concepts necessary to understand the operation of PMMs, while the technology section addresses various applications, like precise biological and chemical sensors, cloaking devices for several frequency ranges, nanoscale photovoltaics, experimental optical computing ...
The Effects Of Organic And Inorganic Nanoparticles On Bacterial Deactivation, 2019 Western Kentucky University
The Effects Of Organic And Inorganic Nanoparticles On Bacterial Deactivation, Lauren Cooper
Honors College Capstone Experience/Thesis Projects
Antibacterial resistance is one of the greatest problems in modern medicine, as healthcare professionals are experiencing more and more difficulty in providing effective care. As such, alternative methods of treatment are needed in order to overcome this issue. One recently proposed method of alternative treatment is photodynamic therapy. Photodynamic therapy is a light-based method of treatment that utilizes (1) a photosensitizing agent, (2) light, (3) produced oxygen species. When the photosensitizing agent is injected into an infected region of interest and then irradiated with a certain wavelength of light, the agent is photoactivated and begins to produce harmful forms of ...
Soft-Matter Damage Detection Systems For Electronics And Structures, 2019 Iowa State University
Soft-Matter Damage Detection Systems For Electronics And Structures, Michael D. Bartlett, Eric J. Markvicka, Ravi Tutika, Carmel Majidi
Materials Science and Engineering Publications
Soft-matter technologies are essential for emerging applications in wearable computing, human-machine interaction, and soft robotics. However, as these technologies gain adoption in society and interact with unstructured environments, material and structure damage becomes inevitable. Here, we present a robotic material that mimics soft tissues found in biological systems to identify, compute, and respond to damage. This system is composed of liquid metal droplets dispersed in soft elastomers that rupture when damaged, creating electrically conductive pathways that are identified with a soft active-matrix grid. This presents new opportunities to autonomously identify damage, calculate severity, and respond to prevent failure within robotic ...
A Dual Nanostructured Approach To Sers Amenable To Large-Scale Production, 2019 Old Dominion University
A Dual Nanostructured Approach To Sers Amenable To Large-Scale Production, Kory Brian Castro
Chemistry & Biochemistry Theses & Dissertations
A SERS device was made using a dual-nanostructured surface comprised of silver nanoparticle and silver nanowires. The ability of each nanostructure to produce a uniform surface was characterized and the surface-enhanced Raman scattering (SERS) response of the resulting surfaces were examined using the reporter molecule 4-aminothiolphenol (ATP) and a 638 nm excitation laser.
A synthetic method was developed to produce silver nanowires with lengths of ~20 μm and diameters of ~100 nm with a narrow size distribution. The method utilized a simple, one-pot synthesis that is amenable to large-scale production. A selective precipitation method was used to the isolate the ...
Off Axis Compressive Response Of Ice-Templated Ceramics, 2019 Old Dominion University
Off Axis Compressive Response Of Ice-Templated Ceramics, Rahul Kumar Jujjavarapu
Mechanical & Aerospace Engineering Theses & Dissertations
The off-axis compressive behavior of ice-templated ceramic was analyzed using experimental results and micro-mechanical model simulation. Ice-templated ceramics is a versatile processing technique used to manufacture anisotropic ceramic foam by exploiting the anisotropic growth characteristics and lamellar morphology. The ice-templating process results in processing-structure-property relationships determined by the microstructure. The processed alumina samples which were later manufactured by water jet machine from the freeze casting were tested under quasi-static off-axis loading conditions and were used to determine the mechanical properties of the material. Digital image correlation (DIC) was used to measure the strain response of ice-templated ceramic under off-axis loading ...