Materials Science and Engineering Commons^™

Chemical Heterogeneity In Electroceramics: The Good, The Bad, And The Difficult To Characterize, Michaela Kuzara, Narit Triamnak, Harlan Brown-Shaklee, David Cann, Geoff Brennecka

Composites at Lake Louise (CALL 2015)

As characterization techniques continue to advance, the materials community is reminded again and again that our samples are not as perfect as we generally describe them to be. This presentation will focus on Bi(Zn_0.5Ti_0.5)O₃–BaTiO₃-based ceramics in which subtle mesoscale cation gradients have been identified as a key factor in the phenomenal temperature- and field-stable permittivity of these unusual dielectrics as well as their remarkably high resistivity values and associated activation energies.[1,2] Earlier work has shown that the single perovskite phase that results after calcination of mixed oxides and carbonates is formed through …

Iron Oxide Thin Film Photoelectrodes For Water Splitting, Avner Rothschild

Composites at Lake Louise (CALL 2015)

Reliable utilization of solar power on a large scale requires affordable energy storage technology, cheaper than batteries, in order to synchronize the variable power production with the changing demand. Likewise, there is a need for renewable fuels to replace fossil fuels. These challenges can be achieved, potentially, by splitting water into hydrogen and oxygen, H₂O à H₂ + ½O₂, using solar power to drive this endergonic reaction uphill. The hydrogen can be stored and converted to electricity and heat on demand. Alternatively, it may serve as feedstock for the production of liquid fuels for transportation …

Nature’S Tough Composites: A Look Into Biological Fibrous Architectures, Christopher Salinas

Composites at Lake Louise (CALL 2015)

Over a period of hundreds of millions of years, numerous examples of biological organisms have evolved light-weight, strong, and tough composite materials in order to adapt to ecological pressures and thrive in their specific niches. These composite structures consist of fiber-reinforced materials with different architectures including lamellar, cellular and helicoidal motifs. This lamellar motif is a common design utilized by a variety of distantly related organisms from mollusks to plants (e.g., queen conch and bamboo). The strength of the structures are dependent on the orientation of the reinforcing fibers. The fiber-matrix interface increases the toughness of the composite through crack …

Increasing Dispersion, Performance, And Pot-Life In Cellulose Nanocrystal/Waterborne Epoxy Composites, Meisha Shofner

Composites at Lake Louise (CALL 2015)

Recent emphasis on the pilot scale production of cellulosic nanomaterials, cellulose nanocrystals (CNCs) and cellulose nanofibrils (CNFs), has increased interest in the effective use of these materials as reinforcements for polymer composites. These studies have been motivated in part by the combination of attractive specific mechanical properties of cellulosic nanomaterials as well as their renewable and possibly sustainable manufacturing routes. The objective of this research complements these efforts and is concerned with more fully understanding the materials design space available for CNC reinforced polymer composites, specifically CNC/waterborne epoxy composites. These composites were processed using different protocols and the structure and …

Radiation Resistance Of Vanadium-Graphene Nanolayered Composites, Seung Min Han

Composites at Lake Louise (CALL 2015)

Metal nanolyered composites are regarded as promising nuclear structural material due to not only the high strength, but due to the ability to absorb the crystalline defects that are introduced from irradiation environment. In this work, vanadium-graphene nanolayered composite is explored for radiation resistance using He ion irradiation tests. Metal-graphene nanolayered composite was previously reported to be ultra high strength due to the effectiveness of graphene in constraining the dislocation motion. Our experimental and MD simulations indicate that the crystalline defects that are produced from He ion irradiations can also absorbed at the metal-graphene interfaces that results in significantly reduced …

Probing Micro- And Nano-Scale Elastic Modulus Variation In Organic-Rich Shale—A Naturally Occurring Composite, Corinne Packard, Taylor Wilkinson, Saeed Zargari, Manika Prasard

Composites at Lake Louise (CALL 2015)

Organic-rich shales are heterogeneous, naturally occurring composites that act as source rocks for oil and gas, which can be extracted through the process of hydraulic fracturing. Shales are composed of clays, minerals, and evolving organic matter and developed through long periods of sedimentation and compression. An elastic modulus mapping technique based on spatially continuous dynamic nanoindentation is applied to map microscale variations in a fine-grained, organic-rich shale consisting of inorganic minerals with an inter-

penetrating network of microscale pores filled with organic matter. A sample of Bakken shale from the Williston Basin was chosen for analysis, in which the organic …

Manufacturing And Testing Of Lightweight, Liner-Less All-Composite Tanks For Storage And Transportation Of Cng, Ranji Vaidyanathan

Composites at Lake Louise (CALL 2015)

Compressed natural gas is one viable fuel source to replace gasoline or diesel in cars, trucks and other passenger vehicles. There are 5 types of tanks that can be used for storage and transportation of CNG. Out of these 5 types, 3 types of tanks have some form of composite structure introduced into the tank construction. Additionally, the type V tank is an all-composite construction, which has not been introduced into the NGV market in a significant manner. In this presentation, we will describe the manufacturing and testing of type V all-composite tanks by the team formed between a small …

In Situ Study Of Phase Transformations And Phase Equilibria In The Tantala And Hafnia Binary System, Waltraud Kriven

Composites at Lake Louise (CALL 2015)

Tantala (Ta₂O₅) has useful dielectric, optical, catalytic and chemical properties while hafnia (HfO₂) has found applications as a high temperature structural ceramic. Tantala and hafnia ceramics have yet to be studied in detailed. During this study, the Ta₂O₅-HfO₂ binary system was investigated using high temperature x-ray diffraction from room temperature to 1650˚C in air using synchrotron radiation. The crystal structures of Ta₂O₅, HfO₂ and Hf₆Ta₂O₁₇ were examined with their corresponding phase transformations and 3-D thermal expansions.

Preparation Of Chitosan-Siloxane Porous Hybrids With Hydroxyapatite For Repair Of Skull Defect, Yuki Shirosaki

Composites at Lake Louise (CALL 2015)

A craniotomy is performed for various neurological diseases, injuries, or conditions such as brain tumors, hematomas, aneurysms, and skull fractures. First, the small-sized holes, called “burr holes” were made to insert some surgical tools such as a shunt, a drain, an intracranial pressure monitor, and endoscope, etc. or be the starting point of removing large skull fracture. After surgery, the holes should be closed by the calcium phosphate cements or the titanium plates, because the skull defects are not spontaneously regenerated.

Calcium phosphate cements (CPCs) have attracted great interest as bone substitute material. However, the cements easily flow into the …

Exploration Of The Materials Paradigm With Respect To Bioinspiration, John Nychka

Composites at Lake Louise (CALL 2015)

From the perspective of materials science and engineering the materials paradigm has traditionally been made of four grouped, and interrelated, fundamental aspects of materials: structure, properties, processing/synthesis, and performance. In order to make connections between these aspects we often rely on characterization techniques. When considering the field of bioinspiration, does the materials paradigm adequately cover what nature has to offer? Our way of approaching the issue of bioinspiration has largely been based in applying the materials paradigm, however, is there anything missing in our approach? Can we map nature to the materials paradigm? How can we? What can the paradigms …

Enhancing Grain Boundary Ionic Conductivity In Mixed Ionic Electronic Conductors, Kyle Brinkman, Ye Lin, Shumin Fang, Frank Chen, Dong Su

Composites at Lake Louise (CALL 2015)

The emergent properties arising from the interactions of phases including interfacial contributions and phase evolution at the mesoscale present new opportunities, as well as challenges, for materials performance and functionality. Mixed ionic-electronic conductors are widely used in devices for energy conversion and storage. Grain boundaries in these materials have nanoscale spatial dimensions, which can generate substantial resistance to ionic transport due to dopant segregation. Here, we report a concept of targeted phase formation in a Ce_0.8Gd_0.2O_2-δ-CoFe₂O₄ (CGO-CFO) composite that serves to enhance the grain boundary ionic conductivity. Using spatially resolved electron …

Characterizing The Functionality Of Transmembrane Ion Channels Using Planar Bilayer Membranes Device And Stopped Flow Spectrometer, Andrew Jo, Hiofan Hoi, C. Montemagno

Composites at Lake Louise (CALL 2015)

Transmembrane ion channels can be used in biomaterials as a way to selectively allow only certain molecules to pass through a given membrane. To produce these types of membranes predictably and reliably for commercial activity, its characterization is crucial. We have characterized the conductivity and ion selectivity of NaChBac, a voltage-gated sodium channel from Bacillus haloduran, using a planar bilayer membrane device. Furthermore, we have devised a dye-free flux assay to measure the channel function using stopped flow spectrometer.. Planar bilayer membrane is a common technique for ion channels function characterization. We first incorporated purified NaChBac protein into lipid vesicle. …

Experimentally Characterizing The Behavior Of Fiber Reinforced Composite Laminates Under Multi-Axial Loading: A Historical Review And Current State Of The Art, John Wolodko

Composites at Lake Louise (CALL 2015)

The mechanical behaviour of fibre reinforced composite laminates under applied loading is a complex process due to a variety of factors including geometry effects at various scales (micro-, meso- and macro-level), complex constitutive responses, and the interaction and competition between progressive damage modes. While the study of fibre reinforced composite laminates under multi-axial loading conditions has been an area of study for over 40 years, the number of experimental studies is limited primarily due to the difficulty in performing relevant experiments. The importance of these types of experiments, however, is critical to help advance the understanding and prediction of laminate …

Using Polymer Brushes To Tune The Structure-Plasmonic Relationship In Polymer Nanocomposites Containing Nanorods, Russell Composto

Composites at Lake Louise (CALL 2015)

The thermodynamic factors that affect the dispersion of polymer-brush grafted gold nanorods (NRs) added to polymer matrix films have been studied by experiment and theory. When the brush (degree of polymerization N) and matrix (degree of polymerization P) have a favorable interaction (enthalpy driven), NRs uniformly disperse in the matrix, independent of P/N. When the brush and matrix are chemically similar, NRs randomly disperse for P/N < 2 (i.e., wet brush), but align side-by-side for P/N > 2. UV-visible spectroscopy is used to investigate the structure-optical property relationship as function of P/N. For P/N > 2, self-consistent field theory (SCFT) and density functional theory (DFT) indicate that NR aggregation correlates with rod-rod …

Electronic And Optical Hybrid Materials Via Self-Assembly And Nanoimprint Lithography, Jim Watkins

Composites at Lake Louise (CALL 2015)

Polymer/nanoparticle hybrid materials organized at the local level by additive driven self-assembly and patterned at the device level using nanoimprint lithography offer versatile approaches to the solution-based fabrication of nanostructured devices. Block copolymers have long held promise for templating periodic functional materials, however the ability to fabricate well-ordered composites with high loadings of nanoparticles and with domain sizes large enough to be useful for the manipulation of visible light has remained challenging. We demonstrate the formation of well-ordered nanocomposites with tunable magnetic and optical characteristics containing up to 70 wt. % of metal, metal oxide and/or semiconducting nanoparticles through phase …

Mechanical Behavior And Properties Of Repo4 Studied By Nanoindentation, Corinne Packard

Composites at Lake Louise (CALL 2015)

Rare-earth orthophosphates (REPO₄s) have been used in experimental fiber matrix composites and are known to deform via a variety of mechanisms including dislocation motion, fracture, twinning, and pressure-induced phase transformations. REPO₄ with RE in the range of Z=64-66 (Gd-Dy) are particularly interesting due to their proclivity for polymorphism and phase transformation. To date, the behavior of these materials has been briefly studied using nanoindentation; however, detailed analysis of the indentation curves is made difficult due to the large number of potential deformation mechanisms. This study analyzes the behavior of nanoindentation load-depth curves and mechanical properties collected from …

Ductile Organic Aerogels For Multifunctional Applications, Hongbing Lu

Composites at Lake Louise (CALL 2015)

Monolithic polyurea aerogels were prepared by controlling the relative isocyanate/water/catalyst (Et3N) ratio in acetone, acetonitrile, or DMSO to prevent precipitation, yielding polyurea (PUA) gels which can be subsequently dried to form highly porous (up to 98.6% v/v) aerogels over a very wide range of densities (0.016-0.55 g cm^-3). The method has been implemented successfully with several aliphatic and aromatic di and triisocyanates. Polyurea aerogels were then studied at the molecular level, the elementary nanoparticle level, and the microscopic level. Their porous structure was probed with N₂-sorption porosimetry. Despite that the nanomorphology varies with density from fibrous …

Thermal Expansion And Phase Transformation Behavior In The Rare-Earth Titanate System, Waltraud Kriven, Kevin Seymour

Composites at Lake Louise (CALL 2015)

The thermal expansion and phase transformation behavior in the rare-earth titanate system has not been well understood. Much of the previous work in this material system was performed ex situ and reveals little information about the thermal expansion, mechanisms behind this expansion, and the relationship between the orthorhombic and hexagonal phases with temperature.

In this paper, a unique method using a thermal image furnace and synchrotron radiation was employed to monitor crystallographic changes in this material system in situ to determine the thermal expansion tensor and describe the mechanism behind such behavior. In addition, this information was paired with insights …

Role Of Interfaces In Polymer Matrix Composites And Methodologies To Improve And Characterize Interfaces In Composites, B.K Khatiwada

Composites at Lake Louise (CALL 2015)

Interfaces in composite materials play disproportionate roles in the ultimate physical properties in systems where polymers are used. Generally, the adsorption of polymers on solid substrates changes the behavior of the polymers at the interface. These changes can be dramatic and have major effects on the mechanical and chemical properties of the composite materials. The distance scales over which these changes occur are small, even as small as 10 nm or less (often less than the unperturbed radius of the molecule) and it is difficult to use many standard techniques to study them. The focus of the work presented here …

Oxygen And Carbon Dioxide Separation Membranes Based On Mixed Conductors, Hitoshi Takamura

Composites at Lake Louise (CALL 2015)

Gas separation is one of the key technologies to improve the efficiency of combustion process, and to reduce the emission of global warming gases. By using pure or concentrated oxygen, flame temperature governing the Carnot efficiency and the concentration of CO₂ in exhaust gas can be raised. Among a number of oxygen separation techniques such as cryogenic separation, oxygen separation membranes based on mixed oxide-ion and electronic conductors have been attracting much attention because of its high selectivity (100% in principle) and the ease of integration into various combustion systems. Figure 1(a) shows how the oxygen separation membrane works; …