Materials Science and Engineering Commons^™

Oxidation Kinetics Of Nicrofer-6025ht For Use In Elevated Temperature Electrochemical Devices, Tyler Cook, Alan Meier, Ph.D.

TECHxpo

Recent advances in high temperature electrochemical devices have prompted research into potential materials for component fabrication.

Processing And Characterization Of Zr-Based Metallic Glass By Laser Direct Depositon, Heehun Bae

Open Access Theses

Bulk Metallic Glass has become famous for its exceptional mechanical and corrosion properties. Especially, Zirconium has been the prominent constituent in Bulk Metallic Glass due to its superior glass forming ability, the ability to form amorphous phase with low cooling rate, thereby giving advantages in structural applications.

In this study, Zirconium powder was alloyed with Aluminum, Nickel and Copper powder at an atomic ratio of 65:10:10:15, respectively. Using the ball milling process to mix the powders, Zr65 Al10 Ni 10 Cu15 amorphous structure was manufactured by laser direct deposition.

Laser power and laser scanning speed were optimized to increase the …

Shear Rheological Characterization Of Gel Healing Response And Construction Of Rheo-Piv System, Abhishek Deepak Bawiskar

Open Access Theses

Thermo-reversible gels are solvent-filled 3D networks of polymer chains interconnected by physical (transient) crosslinks. On applying a high shear stress, the crosslinks are broken and these gels show a typical stress-strain behavior due to cohesive fracture of the gel. When heated above a critical temperature and cooled back to room temperature, all the crosslinks are re-formed. Interestingly, partial to full recovery of broken crosslinks is also observed by simply letting the gel stand at room temperature. In this study, the fracture and healing behavior of a model acrylic triblock copolymer gel has been characterized by shear rheometry. A mathematical model …

Effect Of Multivalent Ions On The Swelling And Mechanical Behavior Of Superabsorbent Polymers (Saps) For Mitigation Of Mortar Autogenous Shrinkage, Qian Zhu

Open Access Theses

The chemical and physical structure-property relationships of model superabsorbent polymer (SAP) hydrogels were characterized with respect to swelling behavior and mechanical properties in different ionic solutions (Na+ , Ca2+ , and Al3+ ). The model hydrogels were composed of poly(sodium acrylate-acrylamide) (PANa-PAM) copolymer with varying concentrations of PANa (0, 17, 33, 67, and 83 wt.%) and covalent crosslinking densities of 1, 1.5, and 2 wt.%. By synthesizing the hydrogels in-house, systems with independently tunable amounts of covalent crosslinking and anionic functional groups were created, allowing for the relative effects of covalent and ionic crosslinking on the properties of the hydrogels …

Design Of A Uv Curing Cartridge For 3d Inkjet Printing, Richard Wiswell

Thinking Matters Symposium Archive

In printing multi-layer electronic circuits, each layer must be formed as a continuous pattern in high resolution from ink jetted liquid droplets and be in precise alignment with the other layers, precluding substrate removal for UV curing. This research seeks to determine the optimal method for in-situ UV curing of the ink jetted material in a single pass. The inkjet replacement cartridge designed for this purpose was constructed of aluminum, fit into the printer head assembly in good alignment with the other ink cartridges, and contained a UV LED for in-situ curing and a cooling fan to maintain safe operating …

Section Abstracts: Astronomy, Mathematics, And Physics With Materials Science

Virginia Journal of Science

Abstracts of the Astronomy, Mathematics, and Physics with Materials Science Section for the 92nd Annual Meeting of the Virginia Academy of Science, May 13-15, 2014, Virginia Commonwealth University, Richmond, Virginia

Functionalization Of Carbon Nanotube Yarn By Acid Treatment, Heath E. Misak, Ramazan Asmatulu, Mat O'Malley, Emil Jurak, Shankar Mall

Faculty Publications

Carbon nanotube (CNT) yarn was functionalized using sulfuric and nitric acid solutions in 3:1 volumetric ratio. Successful functionalization of CNT yarn with carboxyl and hydroxyl groups (e.g., COOH, COO–, OH, etc.) was confirmed by attenuated total reflectance spectroscopy. X-ray diffraction revealed no significant change to the atomic in-plane alignment in the CNTs; however, the coherent length along the diameter was significantly reduced during functionalization. A morphology change of wavy extensions protruding from the surface was observed after the functionalization treatment. The force required to fracture the yarn remained the same after the functionalization process; however, the linear density was increased …

Synthesis Of Nanolaminate Structures Of Alternating Layers Of Lead Telluride And Lead Selenide By Atomic Layer Deposition For Thermoelectric Applications, Arun Deepak Ramalingom Pillai

Electrical & Computer Engineering Theses & Dissertations

Alloys composed of lead, telluride and selenide compounds exhibit very high figure of merit ZT values at intermediate temperatures, making them exceptional thermoelectric materials in a particular temperature range. Advancement in thermoelectric devices and applications hinges on increasing ZT, which is a ratio of the thermoelectric power factor to the thermal conductivity. One of the proposed avenues to achieving this goal is the use of low dimensional structures such as quantum wells, quantum dots, superlattices (SL) and nanolaminates to affect heat transport. SL structures can effectively confine charge carriers as well as scatter phonons which contribute significantly to thermal conductivity. …

Examining The Freezing And Thawing Behavior Of Concretes With Improved Performance Through Internal Curing And Other Methods, Wesley A. Jones

Open Access Theses

Internally cured (IC) concrete has been emerging over the last decade as an effective way to improve the performance of concrete. IC holds promise for producing concretes with an increased resistance to early-age cracking and ultimately enhancing the durability of structures. It is a simple and effective way to ensure proper hydration of cementitious material in high performance concrete mixtures; mixtures in which traditional, external, curing can be ineffective. IC supplies water that is necessary to relieve stress buildup from chemical shrinkage and in turn helping to prevent early age shrinkage cracking.^ The first part of this thesis presents and …

Microstructural Indicators Of Transition Mechanisms In Time-Dependent Fatigue Crack Growth In Nickel Base Superalloys, Ann Elizabeth Heeter

Open Access Theses

Gas turbine engines are an important part of power generation in modern society, especially in the field of aerospace. Aerospace engines are design to last approximately 30 years and the engine components must be designed to survive for the life of the engine or to be replaced at regular intervals to ensure consumer safety. Fatigue crack growth analysis is a vital component of design for an aerospace component. Crack growth modeling and design methods date back to an origin around 1950 with a high rate of accuracy. The new generation of aerospace engines is designed to be efficient as possible …

Cztsse Thin Film Solar Cells : Surface Treatments, Chinmay S. Joglekar

Open Access Theses

Chalcopyrite semiconducting materials, specifically CZTS, are a promising alternative to traditional silicon solar cell technology. Because of the high absorption coefficient; films of the order of 1 micrometer thickness are sufficient for the fabrication of solar cells. Liquid based synthesis methods are advantageous because they are easily scalable using the roll to roll manufacturing techniques.

Various treatments are explored in this study to enhance the performance of the selenized CZTS film based solar cells. Thiourea can be used as a sulfur source and can be used to tune band gap of CZTSSe. Bromine etching can be used to manipulate the …

Detailed Finite Element Analysis And Preliminary Study Of The Effects Of Friction And Fastener Pre-Tension On The Mechanical Behavior Of Fastened Built-Up Members, Francisco Javier Bonachera Martin

Open Access Theses

The characterization of fatigue resistance is one of the main concerns in structural engineering, a concern that is particularly important in the evaluation of existing bridge members designed or erected before the development of fatigue design provisions. The ability of a structural member to develop alternate load paths after the failure of a component is known as member-level or internal redundancy. In fastened built-up members, these alternate load paths are affected by the combination of fastener pre-tension and friction between the structural member components in contact. In this study, a finite element methodology to model and analyze riveted and bolted …

Blast Energy Mitigation In Porous Rocks, Brittany Corinne Essink

Open Access Theses

Geo-materials are commonly used and sought after for blast mitigation applications due to their wide availability and low cost compared to industry trademarked materials. Characterization of these natural geo-materials such as volcanic rocks is of paramount importance in determining their blast mitigation capabilities. While there is a large amount of information available for materials such as concrete or sand blasts, information on the properties of volcanic rocks is far more scarce. This lack of data is due to the wide range of existing natural volcanic rocks and the variation in the minerals and pore structures of the rocks.

In this …

Dynamic Characteristic Identification Of Seismic-Excited Multi-Story Buildings Through Response-Only Technique, Agung Budipriyanto, Priyo Suprobo

Makara Journal of Technology

Identifying dynamic characteristics of civil engineering structures is still a challenging task. It intends to assess behavior of the structures under time-dependent loads. This paper discusses a methodology suitable for identifying the characteristics of multi-story buildings using only their measured response under earthquake ground excitations. Appropriateness of technique used for structural identification was corroborated through coherence of the structure’s responses. The methodology was applied for identifying the characteristics of 14-story and 20-story office buildings located in a high seismic region. Responses of these two buildings recorded during three different seismic ground motions were investigated. The buildings’ response spectral densities and …

Synthesis And Characterization Of Soy-Based Polyurethane Foam With Utilization Of Ethylene Glycol In Polyol, Flora Elvistia Firdaus

Makara Journal of Technology

The use of vegetable oils on replacing petroleum has attracted attention of many researchers. The chemical structure of vegetable oils are different from petrochemicals, so the structure of soybean oil has to be chemically modified through its unsaturated fatty acid chain in triglyceride. A two step process was conducted for the preparation of soy-polyol in designated temperatures; 50 °C, 60 °C, and 70 °C. Ethylene glycol (EG) as co-reagent was taking part in soy-polyol synthesis, and the soy-polyol was used as a sole polyol for polyurethane synthesis. Referred to the previous study, the existence of EG in polyurethane synthesis can …

Performances Of Free-Space Optical Communication System Over Strong Turbulence, Ucuk Darusalam, Purnomo Sidi Priambodo, Harry Sudibyo, Eko Tjipto Rahardjo

Makara Journal of Technology

We report an experimental of free-space optical communication (FSOC) system that use tube propagation simulator (TPS) as the turbulence medium. The FSOC system use wavelength of 1550 nm at the rate transmission of 1000 Mbps and amplified with EDFA at the output of +23 dBm. Index structure of 10-15–10-13 as the representation of atmosphere index turbulences are used for simulation of intensity distribution model or scintillation. The simulation use gammagamma and K model as well. The beam wave propagation models used in simulation are plane wave, spherical wave and Gaussian wave. Spherical wave achieves highest performance via gamma-gamma in strong …

Preparations Of Nanostructured Silicide Bundles And Oxide Arrays, Hirokazu Tatsuoka, Wen Li, Erchao Meng, Daisuke Ishikwa, Kaito Nakane, Shingo Oda, Tomoji Matsushita, Natsuki Kurebayashi

Makara Journal of Technology

A variety of nanostructured silicide bundles and oxide nanowire arrays with abundant, non-toxic materials we are prepared. The CrSi2 nanowire and Mg2Si/MgO composite nanowire bundles were synthesized using a Si substrate and a SiOx nanofiber bundle, respectively. The hexagonal MoSi2 nanosheet bundles were also synthesized using a MoS2 layered material as a template. In addition, ZnO, CuO/Cu2O and a-Fe2O3 nanowire arrays were prepared on semiconductor or metallic substrates. The growth phenomena and the structural properties of the nanostructured materials awere investigated. In addition, the preparations of axial and radial nanowire structures weare examined.

Bioethanol Production From Iles-Iles And Sorghum Starch As Raw Materials (Effect Of Cacl 2 Addition And Saccharification Time), Kusmiyati Kusmiyati, Ali Mahmudi

Makara Journal of Technology

Bioethanol produced from agricultural sources is one alternative energy that has been developed to substitute for petroleum. However, the use of food sources such as corn and cassava to produce bioethanol still face obstacles that lead to the scarcity of food and an increase in food prices. The aim of this study was to produce bioethanol from sorghum and iles-iles, which are not used by humans as food, especially in Indonesia. For both materials, the variables studied were saccharification time (4, 8, 24, and 48 h) and concentration of CaCl2 added to the liquefaction slurry (0, 100, 200, 300, and …

The Effect Of Zephyr Layer Orientation On Zephyrboard Made From Oil Palm Petiole, Lusita Wardani, Muhamad Yusram Massijaya, Yusuf Sudo Hadi, I Wayan Darmawan

Makara Journal of Technology

It is very important to utilize oil palm petiole for the production of zephyr boards. This study aimed to analyze the effect of layer orientation on zephyr board quality. Zephyr boards were made with three coating patterns (A = cross perpendicular, B= combine A and C, and C= paralell) and five zephyr layers using urea formaldehyde adhesive. They were pressed for 20 min at a pressure of 25 kgf/cm² and a temperature 120 ºC, to a target density of 0.80 g/cm³ and a size of 300 mm X 300 mm X 12 mm. Our results showed that the physical and …

Performance Evaluation Of An Optimized Floating Breakwater In Oblique Waves With A Higher-Order Boundary Element Method, Faisal Mahmuddin, Masashi Kashiwagi

Makara Journal of Technology

In the previous study, the optimal performance of a two-dimensional (2D) floating breakwater shape was obtained. The performance of this shape was also confirmed with a model experiment in a towing tank. Moreover, the shape’s performance in three dimensions (3D) was investigated in a subsequent study. However, to predict the shape’s performance in a real application more accurately, the shape’s characteristics in oblique waves must also be evaluated. In this study, the performance and characteristics of the model (hydrodynamic forces, body motions, wave elevations, and drift forces) are computed using a higher-order boundary element method (HOBEM). The HOBEM, which is …

Co2 Recycling Using Microalgae For The Production Of Fuels, Michael H. Wilson, John Groppo, Andrew Placido, S. Graham, S. A. Morton Iii, Eduardo Santillan-Jimenez, Aubrey Shea, Mark Crocker, Czarena Crofcheck, Rodney Andrews

Center for Applied Energy Research Faculty and Staff Publications

CO₂ capture and recycle using microalgae was demonstrated at a coal-fired power plant (Duke Energy’s East Bend Station, Kentucky). Using an in-house designed closed loop, vertical tube photobioreactor, Scenedesmus acutus was cultured using flue gas as the CO₂ source. Algae productivity of 39 g/(m² day) in June–July was achieved at significant scale (18,000 L), while average daily productivity slightly in excess of 10 g/(m² day) was demonstrated in the month of December. A protocol for low-cost algae harvesting and dewatering was developed, and the conversion of algal lipids—extracted from the harvested biomass—to diesel-range hydrocarbons via catalytic …

Investigation Of The High-Temperature Redox Chemistry Of Sr2Fe1.5Mo0.5O6-Δ Via In Situ Neutron Diffraction, Daniel E. Bugaris, Jason P. Hodges, Ashfia Hug, W. Michael Chance, Andreas Heyden, Fanglin Chen, Hans-Conrad Zur Loye

Faculty Publications

Crystallographic structural changes were investigated for Sr₂Fe_1.5Mo_0.5O_6−δ, an electrode material for symmetric solid oxide fuel cells. The samples of this material were heated and cooled in wet hydrogen and wet oxygen atmospheres, to simulate the reducing and oxidizing conditions experienced under actual fuel cell operating conditions, and their structures and oxygen contents were determined using in situ powder neutron diffraction. The existence of a reversible tetragonal to cubic phase transition was established to occur between room temperature and 400 °C, both on heating and cooling in either oxygen or hydrogen. The …

Porous Nanocomposites With Integrated Internal Domains: Application To Separation Membranes, Wenle Li, John Y. Walz

Chemical and Materials Engineering Faculty Publications

Asymmetric membranes with layered structure have made significant achievements due to their balanced properties and multi-functionalities that come from a combination of multiple layers. However, issues such as delamination and substructure resistance are generated by the intrinsic layered structure. Here, we present a strategy to integrate the traditional layered structure into an asymmetric but continuous porous network. Through infiltrations of microparticles and nanoparticles to targeted regions, active domains are created inside the porous scaffold versus having them applied externally. The fabricated internal active domains are highly adjustable in terms of its dimensions, pore size, and materials. We demonstrate that it …

Mos2 Functionalization For Ultra-Thin Atomic Layer Deposited Dielectrics, Angelica Azcatl, Stephen Mcdonnell, Santosh Kc, Xin Peng, Hong Dong, Xiaoye Qin, Rafik Addou, Greg Mordi, Ning Lu, Jiyoung Kim, Moon Kim, Kyeongjae Cho, Robert Wallace

Faculty Publications

The effect of room temperature ultraviolet-ozone (UV-O3) exposure of MoS2 on the uniformity of subsequent atomic layer deposition of Al2O3 is investigated. It is found that a UV-O3 pre-treatment removes adsorbed carbon contamination from the MoS2 surface and also functionalizes the MoS2 surface through the formation of a weak sulfur-oxygen bond without any evidence of molybdenum-sulfur bond disruption. This is supported by first principles density functional theory calculations which show that oxygen bonded to a surface sulfur atom while the sulfur is simultaneously back-bonded to three molybdenum atoms is a thermodynamically favorable configuration. The adsorbed oxygen increases the reactivity of …

Carbon Allotrope Dependence On Temperature And Pressure During Thermal Decomposition Of Silicon Carbide, Munson J. Anderson

Theses and Dissertations

Bulk CNT and graphene films form on SiC using a metal-catalyst-free thermal decomposition approach. In this work, the background vacuum pressure and temperature used in the decomposition process are varied to investigate their impact on the type and quality of carbon allotrope formed on the SiC substrate. The carbon nanostructure growth is performed using two approaches, both of which involve intense heating (1400-1700°C) of SiC under moderate vacuum conditions (0.01 - 0.00001 Torr). The first growth method uses a conventional graphite resistance furnace capable of annealing waferscale samples over 1700°C under vacuum. Using this approach, post-growth characterization is performed using …

Experimental Investigation Of Mechanical Behavior Of An Oxide/Oxide Ceramic Composite In Interlaminar Shear And Under Combined Tension-Torsion Loading, Skyler R. Hilburn

Theses and Dissertations

Creep behavior in interlaminar shear of an oxide-oxide ceramic composite, Nextel 720™/aluminosilicate (N720/AS), was investigated at 1100°C in laboratory air and in steam. The interlaminar shear strength (ILSS) was determined as 7.65 MPa. The creep behavior was examined for interlaminar shear stresses in the 2-6 MPa range. Primary and secondary creep regimes were observed in all tests conducted in air and in steam. Tertiary creep was noted in the tests performed at 6 MPa. Larger creep strains and higher creep strain rates were produced in steam. Surprisingly, the presence of steam had a beneficial effect on creep lifetimes. It appears …

Hydrothermal Crystal Growth Of Lithium Tetraborate And Lithium 𝛾-Metaborate, Jeffrey J. Graham

Theses and Dissertations

Growth of lithium tetraborate by the hydrothermal method was attempted in 10^-6 M LiOH, both by spontaneous nucleation and transport growth. Tetraborate grew out of the first spontaneous nucleation reaction, while the seed dissolved and lithium gamma-metaborate formed during the transport growth reactions. A species thermodynamic stability study showed gamma-metaborate formed exclusively from 350°C to 550°C, and Li₃B₅O₈(OH)₂ was observed at 250°C; tetraborate was not observed. A solubility study on lithium tetraborate did not achieve equilibrium conditions, but did demonstrate that gamma-metaborate is significantly more thermodynamically stable than tetraborate under the tested …

Memristive Responses Of Jammed Granular Copper Array Sensors To Mechanical Stress, Gary A. Willey

Theses and Dissertations

A granular memristive device with the end goal of creating a novel system protection device is introduced in a 1-Dimension array. The electromechanical network will lay the groundwork for future 2-Dimensional and 3-Dimensional devices for simultaneous protection from intrusion. Off the shelf copper spheres with diameter of 710 ± 11microns were found through nano-indentation measurements to have elastic modulus of 106GPa, and compressive yield strength of 729MPa, these spheres were prepared for test in a 1-Dimensional array device. The arrays response to mechanical perturbations modeled by Hertz contact mechanics can be monitored by simultaneous electrical measurements across the multiple metal-insulator-metal …

Post-Fracture Capacity Of Railroad Flat Car Bridges, Teresa L. Washeleski

Purdue Road School

Railroad flatcars (RRFCs) are a convenient option to replace existing deteriorating bridge structures on low-volume roads. They are typically used as the bridge superstructure by placing two or more flatcars side-by-side to achieve the desired bridge width. Utilizing RRFCs as a bridge allows for rapid construction and greater cost savings compared to traditional practices. These benefits make them an attractive solution for rural communities in Indiana, as well as other states.

Uncertainty remains about the response under higher loads than could be easily achieved in the field and the level of redundancy of railroad flatcar bridges. Using RRFCs as bridges …

Post-Failure Capacity Of Built-Up Steel Members, Matthew H. Hebdon

Purdue Road School

Mechanically fastened built-up steel members have long been known to possess internal member redundancy and, as a result, multiple load paths which can be exploited to increase their functional life. Internal redundancy provides the ability to resist total member failure in the event of a fracture of an individual component. However, there is little experimental data in the literature regarding post-fracture capacity in terms of strength and subsequent fatigue life. The experimental study currently underway will provide needed information on parameters that affect the ability of built- up members to arrest a fracture as well as the available remaining fatigue …