Engineering Commons^™

Finite Element Analysis (Fea) Study Of The Thermal Stress Concentrations In Planar-Type Sodium Sulfur (Nas) Secondary Batteries, Jeffrey P. Colker

Theses and Dissertations

The importance of a reliable and safe way to store energy, and allow for on-demand usage, has led to much research in the field of secondary battery development. The thesis herein explores a technology that has shown promising results when implemented in large-scale energy grid applications. Though the technology has proven viable in both load-leveling on existing grids as well as serving to legitimize renewable energy sources, the development of such advanced battery systems is not without challenge. Sodium-sulfur (NaS) secondary cells have shown promising results when implemented in the aforementioned energy storage applications. One of the main drawbacks to …

Investigation Of Electrolyte Wetting In Lithium Ion Batteries: Effects Of Electrode Pore Structures And Solution, Yangping Sheng

Theses and Dissertations

Beside natural source energy carriers such as petroleum, coal and natural gas, the lithium ion battery is a promising man-made energy carrier for the future. This is a similar process evolved from horse-powered era to engine driven age. There are still a lot of challenges ahead like low energy density, low rate performance, aging problems, high cost and safety etc.

In lithium ion batteries, investigation about manufacturing process is as important as the development of material. The manufacturing of lithium ion battery, including production process (slurry making, coating, drying etc.), and post-production (slitting, calendering etc.) is also complicated and critical …

Thermodynamic And Kinetic Simulation Of Transient Liquid-Phase Bonding, Brad Allen Lindner

Theses and Dissertations

ABSTRACT

THERMODYNAMIC AND KINETIC SIMULATION OF TRANSIENT LIQUID-PHASE BONDING

by

Brad Lindner

The University of Wisconsin-Milwaukee, 2015

Under the Supervision of Professor Benjamin C. Church

The use of numeric computational methods for the simulation of materials systems is becoming more prevalent and an understanding of these tools may soon be a necessity for Materials Engineers and Scientists. The applicability of numerical simulation methods to transient liquid-phase (TLP) bonding is evaluated using a type 316L/MBF-51 material system. The comparisons involve the calculation of bulk diffusivities, tracking of interface positions during dissolution, widening, and isothermal solidification stages, as well as comparison of …

The Optimization Of Concrete Mixtures For Use In Highway Applications, Mohamadreza Moini

Theses and Dissertations

Portland cement concrete is most used commodity in the world after water. Major part of civil and transportation infrastructure including bridges, roadway pavements, dams, and buildings is made of concrete. In addition to this, concrete durability is often of major concerns. In 2013 American Society of Civil Engineers (ASCE) estimated that an annual investment of $170 billion on roads and $20.5 billion for bridges is needed on an annual basis to substantially improve the condition of infrastructure. Same article reports that one-third of America’s major roads are in poor or mediocre condition [1]. However, portland cement production is recognized with …

Tin Nanoparticles Encapsulated In Hollow Tio2 Spheres As High Performance Anode Materials For Li-Ion Batteries, Xiang Pan

Theses and Dissertations

Tin, an anode material with a high capacity for lithium-ion batteries, has poor cyclic performance because of the high volume expansion upon lithiation. Based on a literature review of the applications of lithium-ion batteries and current research progress of the tin-based anode materials for lithium-ion batteries, we developed a method to synthesize hollow TiO2 spheres with tin nanoparticles anchored on the inner surface of the TiO2 shell. Such a unique tin/TiO2 composite alleviates the volume change of tin–based anode materials in charge-discharge processes. SnCl2·2H2O (Tin (II) chloride dihydrate) and titanium (IV) isopropoxide (TIPT) were used as the Sn source and …

A Study On The Synthesis - Structure - Property - Performance Relationship Of Bulk Functionalized Polyurethane Foams For Water Filtration Applications, Subhashini Gunashekar

Theses and Dissertations

Polymers, macromolecules made of repeat units, are one of the major building blocks of life. They exist naturally in the form of DNA, proteins, sugars, cellulose, natural rubber etc. However, it was only in the mid twentieth century man began to understand its true nature and developed a new class of materials called ‘Plastics’. In recent years, the concept of a truly tailor made polymer has become a reality as a result of better understanding of the polymer structure-property relationships, newer polymerization techniques and due to the availability of new low cost monomers. Polymers from different elements with any desired …

Experimental Evaluation Of The Effect Of Coal Combustion Products On Constructability, Damage And Aging Resistance Of Asphalt Mastics, Emil Garibaldy Bautista

Theses and Dissertations

Developing a cost-efficient and long-term road infrastructure requires innovative approaches that are both green and environmentally sustainable. Today, building a sustainable, long-lasting, and efficient road infrastructure with little or no repairs is a challenging task and highly innovative technological breakthroughs are urgently needed. For many years fly ash has been effectively used as a partial replacement of portland cement in the production of different types of concrete, as well as in embankments and soil stabilization. On the other hand, the use of Coal Combustion Products (CCPs), including fly ash, as a mineral filler in asphalt pavements has been very limited. …

Novel Two-Dimensional Nanomaterials And Their Gas Sensing Properties, Haihui Pu

Theses and Dissertations

Graphene, an atomic thin two-dimensional (2D) material with C atoms arranged in a honeycomb lattice, has sparked an unprecedented research interest across various scientific communities since its initial mechanical isolation in 2004. The linear energy dispersion with respect to the momentum within 1 eV around the Fermi level at the high symmetric K (Dirac) points in the Brillouin zone renders graphene a wonder material for scientists. However, graphene’s semimetallic nature significantly limits its high-end applications, e.g., in digital logic circuits. Therefore, continued efforts in opening the band gap for graphene and in searching for novel 2D semiconducting materials are rewarding. …

The Design Of High Performance And Ultra-High Performance Fiber Reinforced Cementitious Composites With Nano Materials, Scott W. Muzenski

Theses and Dissertations

The use of high performance and ultra-high performance cementitious composites (HPC/UHPC) in critical elements of infrastructure can be a sustainable alternative to conventional concrete. These materials provide superior durability, reducing the need for maintenance and early replacement. The use of special cements and nano-materials improve the strength and durability of HPC/UHPC composites by providing a denser microstructure. The addition of high performance fibers enhances the ductility and restricts the crack size, reducing water penetration in cracked material. In HPC, the addition of superhydrophobic admixtures further reduces water permeability and thus provides superior durability and freeze-thaw resistance by producing a preferred …