Materials Science and Engineering Commons^™

Söyleşi- Rauf H Eric, Güney Afrika'da Madencilik Ve Metal Kazanımı (Interview With Rauf H Eric, Mining And Metal Extraction In South Africa), Ahmet Deniz Bas

Ahmet Deniz Bas

No abstract provided.

Methods For Analyzing The Structure Of Creases In Heat Sealed Paperboard Packages, Ville Leminen, Petri Mäkelä, Panu Tanninen, Juha Varis

Journal of Applied Packaging Research

Press-forming of paperboard has been previously studied by several authors. A point of interest regarding gas tight heat sealing of the packages are the creases in the package. The objective of this article was to study and compare different microscopic imaging methods to research an optimal imaging method for the formation of creases in the press-forming process of polymer coated paperboard trays. The studied methods were: Scanning electrode microscopy (SEM), X-ray Microtomography, Optical light microscopy and Polarized light microscopy. All four tested methods delivered clear images. Casting of the samples in an acrylic resin and light microscope imaging was found ...

Amine-Pillared Nanosheet Adsorbents For Co2 Capture Applications, Hui Jiang

Chemical Engineering Master's Theses

Amine-functionalized solid adsorbents have gained attention within the last decade for their application in carbon dioxide capture, due to their many advantages such as low energy cost for regeneration, tunable structure, elimination of corrosion problems, and additional advantages. However, one of the challenges facing this technology is to accomplish both high CO₂ capture capacity along with high CO₂ diffusion rates concurrently. Current amine-based solid sorbents such as porous materials similar to SBA-15 have large pores diffusion entering molecules; however, the pores become clogged upon amine inclusion.

To meet this challenge, our group's solution involves the creation of ...

Microanalysis Of Polymer Chain Diffusion In Heat Seals, Russell Cooper

All Theses

Heat sealing is an integral method for the closure and protection of packaging. Previous work has shown that seal strength is developed by the interdiffusion of polymer chains within heat seals. Heat seals were made between two dissimilar materials. Poly(ethylene-co-acrylic acid) (EAA) was heat sealed to ionomer. Diffusion within the EAA-ionomer heat seals was estimated. The diffusion estimates were then related to resulting seal strength in the EAA-ionomer sealant system. Heated tooling sealing was utilized to make heat seals at 40 psi (275.79 kPa), 0.5 seconds, and a range of temperatures between 180˚F (82.22˚C ...

Fabrication And Characterization Of Magnetic Nanoparticle Composite Membranes, Akeem Cruickshank

All Theses

To effectively and accurately deliver drugs within the human body, both new designs and components for implantable micropumps are being studied. Designs must ensure high biocompatibility, drug compatibility, accuracy and small power consumption. The focus of this thesis was to fabricate a prototype magnetic nanoparticle membrane for eventual incorporation into a biomedical pump and then determine the relationship between this membrane deflection and applied pneumatic or magnetic force. The magnetic nanoparticle polymer composite (MNPC) membranes in this study were composed of crosslinked polydimethylsiloxane (PDMS) and iron oxide nanoparticles (IONPs). An optimal iron oxide fabrication route was identified and particle size ...

Synthesis And Characterization Of Chemically Functionalized Shape Memory Nanofoams For Unattended Sensing Applications, Anna Paola Soliani

All Dissertations

The work in this dissertation is devoted to the synthesis and characterization of novel materials for off-line unattended sensing: shape-memory grafted nanofoams. The fabrication process and characterization of highly efficient, polymeric nanosensor element with the ability to selectively detect analytes and retain memory of specific exposure events is reported. These shape memory nanofoams could potentially act as efficient and highly sensitive coatings for evanescent waveguide-based optical monitoring systems. On exposure to specific analytes, the polymeric coatings locally change their internal structure irreversibly at the nanolevel, affecting the local optical properties such as refractive index. Currently, enrichment polymer layers (EPLs) are ...

Customizing Fiber Spinning Approaches For Polymer/Nano-Carbon Composites, Kenan Song

Mechanical Engineering Dissertations

Among the many potential applications of nano-carbon (nC), their ability to improve stiffening, strengthening, and toughening mechanisms in polymeric materials has been given considerable attention due to the excellent mechanical properties, and low density of these graphitic materials. The approaches toward designing composites have provided numerous opportunities for the invention of new materials for applications requiring high-strength and high-modulus. Precise control of processing factors including (i) preserving intact nC structure, (ii) uniform dispersion of the nC in polymers, (iii) effective filler-matrix interfacial interactions, and (iv) alignment/orientation of the nC and/or polymer chains all can contribute to the superior ...

Size Effects In Human Visual Inspection For Micro/Meso Scale Parts, Sri Harsha Kavuri

Mechanical (and Materials) Engineering -- Dissertations, Theses, and Student Research

Visual inspection has been a major method of quality control in conventional manufacturing processes for the last fifty years. Utilizing trained human inspectors to perform this visual inspection has been the most effective means of maintaining quality control. Extensive research has been performed to understand the factors that influence the human inspection process.

In the recent years, there has been a significant emphasis on manufacturing at the smaller end of the size-spectrum such as Micro and Meso scale manufacturing. Quality control at becomes a challenging task due to the extremely small sizes. Several automated visual inspection techniques have been proposed ...

Nanohub.Org: A Gateway To Undergraduate Simulation-Based Research In Materials Science And Related Fields, Tanya A. Faltens, Peter A. Bermel, Amanda Buckles, K Anna Douglas, Alejandro H. Strachan, Lynn K. Zentner, Gerhard Klimeck

Birck and NCN Publications

Our future engineers and scientists will likely be required to use advanced simulations to solve many of tomorrow's challenges in nanotechnology. To prepare students to meet this need, the Network for Computational Nanotechnology (NCN) provides simulation-focused research experiences for undergraduates at an early point in their educational path, to increase the likelihood that they will ultimately complete a doctoral program. The NCN summer research program currently serves over 20 undergraduate students per year who are recruited nationwide, and selected by NCN and the faculty for aptitude in their chosen field within STEM, as well as complementary skills such as ...

Treatment Of A Copper-Rich Gold Ore By Cyanide Leaching, Ammonia Pretreatment And Ammoniacal Cyanide Leaching, Ahmet Deniz Bas, Elif Koc, Ersin Y. Yazici, Haci Deveci

Ahmet Deniz Bas

No abstract provided.

Computational Study Of Microstructure-Propertymechanism Relations In Ferroic Composites, Fengde D. Ma

Dissertations, Master's Theses and Master's Reports - Open

Ferroic materials, as notable members of smart materials, have been widely used in applications that perform sensing, actuation and control. The macroscopic property change of ferroic materials may become remarkably large during ferroic phase transition, leading to the fact that the macroscopic properties can be tuned by carefully applying a suitable external field (electric, magnetic, stress). To obtain an enhancement in physical and/or mechanical properties, different kinds of ferroic composites have been fabricated. The properties of a ferroic composite are determined not only by the properties and relative amounts of the constituent phases, but also by the microstructure of ...

Nudged-Elastic Band Method With Two Climbing Images: Finding Transition States In Complex Energy Landscapes, Nikolai A. Zarkevich, Duane D. Johnson

Ames Laboratory Publications and Papers

The nudged-elastic band (NEB) method is modified with concomitant two climbing images (C2-NEB) to find a transition state (TS) in complex energy landscapes, such as those with a serpentine minimal energy path (MEP). If a single climbing image (C1-NEB) successfully finds the TS, then C2-NEB finds it too. However, improved stability of C2-NEB makes it suitable for more complex cases, where C1-NEB misses the TS because the MEP and NEB directions near the saddle point are different. Generally, C2-NEB not only finds the TS, but also guarantees, by construction, that the climbing images approach it from the opposite sides along ...

Shape-Memory Transformations Of Niti: Minimum-Energy Pathways Between Austenite, Martensites, And Kinetically Limited Intermediate States, Nikolai A. Zarkevich, Duane D. Johnson

Ames Laboratory Publications and Papers

NiTi is the most used shape-memory alloy; nonetheless, a lack of understanding remains regarding the associated structures and transitions, including their barriers. Using a generalized solid-state nudged elastic band method implemented via density-functional theory, we detail the structural transformations in NiTi relevant to shape memory: those between a body-centered orthorhombic (bco) ground state and a newly identified stable austenite (“glassy” B2-like) structure, including energy barriers (hysteresis) and intermediate structures (observed as a kinetically limited Rphase), and between martensite variants (bco orientations). All results are in good agreement with available experiment. We contrast the austenite results to those from the often-assumed ...

Influence Of The Temperature On Flow-Induced Crystallization Of Isotactic Polypropylene And Propylene-Ethylene Random Copolymer, Hugo Boitout

Mechanical (and Materials) Engineering -- Dissertations, Theses, and Student Research

When flow is applied on a semi-crystalline polymer melt, it can greatly impact how it crystallizes its final properties. Therefore, it is crucial to understand the basic mechanism of flow induced crystallization (FIC). Only then will it be possible to predict final properties from the type of resin and processing conditions. Polypropylene is one of the most widely used polymers. Its processing generally involves subjecting the melt to intense flow fields, so FIC commonly occurs.

This study investigates the influence of temperature of shear and crystallization on the FIC behavior of isotactic polypropylene (iPP). Temperature is one of the main ...

Thermophonon, Nikolai A. Zarkevich

Ames Laboratory Software

ThermoPhonon is a stand-alone code, which can be integrated into other software packages. Typically, it is used together with a density functional theory (DFT) code (such as VASP, Wien2k, AbInit, SIESTA) and a phonon code (such as Phonopy or Phon). The workflow is the following.

• Molecular dynamics (MD) in a supercell at a given temperature T is performed using another code. After sufficient equilibration, the output in the form of atomic positions and forces for a large number of selected MD steps is recorded into a file. If needed, one can modify this file by applying additional constraints, such as ...

Microstructure And Magnetic Behavior Studies Of Processing-Controlled And Composition-Modified Fe-Ni And Mn-Al Alloys, Yunlong Geng

Mechanical (and Materials) Engineering -- Dissertations, Theses, and Student Research

L1₀-type (Space group P4/mmm) magnetic compounds, including FeNi and MnAl, possess promising technical magnetic properties of both high magnetization and large magnetocrystalline anisotropy energy, and thus offer potential in replacing rare earth permanent magnets in some applications.

In equiatomic Fe-Ni, the disorder-order transformation from fcc structure to the L1₀ structure is a diffusional transformation, but is inhibited by the low ordering temperature. The transformation could be enhanced through the creation of vacancies. Thus, mechanical alloying was employed to generate more open-volume defects. A decrease in grain size and concomitant increase in grain boundary area resulted from ...

Power Variation With Electret Surface Potential And Frequency Of Vibration In Vertical Vibration Based Cantilever-Electret Micro-Power Generation, Innovative Research Publications Irp India, Akin-Ponnle A.E, Ponnle A.A, Falaki S.O.

Innovative Research Publications IRP India

A cantilever-electret based electrostatic micro-power generator for energy harvesting was set up in which Cyclic Transparent Optical Polymer (CYTOP) was used as the electret, and the upper electrode was made in form of an Ashaped cantilever which was fabricated from materials of copper with embedded glass epoxy. The cantilever was vibrated in the vertical direction in close to contact point mode of operation. Experimental result showed that the average output power increases with increasing electret surface potential, and the minimum distance to contact point decreases with increasing electret surface potential. Also, variation of output power with frequency was investigated by ...

Utilization Of Aqueous Raft Prepared Copolymers To Improve Anticancer Drug Efficacy, Andrew Christopher Holley

Dissertations

The advent of controlled radical polymerization (CRP) techniques, along with advancements in facile conjugation chemistry, now allow synthetic tailoring of precise, polymeric architectures necessary for drug/gene delivery. Reversible addition- fragmentation chain transfer (RAFT) polymerization and its aqueous counterpart (aRAFT) afford quantitative control over key synthetic parameters including block length, microstructure, and placement of structo-pendent and structo-terminal functionality for conjugation of active agents and targeting moieties. The relevance of water-soluble and amphiphilic (co)polymers synthesized by RAFT for in vitro delivery of therapeutics in biological fluids is an especially attractive feature. In many cases, polymerization, binding ...

Zone Refining Of Raw Materials For Metal Halide Scintillator Crystal Growth, Thomas Williams Mcalexander

Masters Theses

In recent years, scintillators have been researched for homeland security applications where properties such as high light output and low energy resolution are required for efficient gamma ray spectroscopy. Several promising scintillators, including SrI₂ [Strontium Iodide], CsSrI₃ [Cesium Strontium Iodide]_, and KSr₂I₅ [Potassium Strontium Iodide] are activated with EuI₂ [Europium Iodide]. The quality of EuI₂ raw material is generally poor and inconsistent as-received from the manufacturer. Material purity is known to affect its scintillation performance, and so purification processes have been investigated to improve the performance of Eu-doped [Europium-doped] scintillators. In this work ...

Low Molecular Weight Glucosamine/L-Lactide Copolymers As Potential Carriers For The Development Of A Sustained Rifampicin Release System: Mycobacterium Smegmatis As A Tuberculosis Model, Jorge Ragusa

Chemical & Biomolecular Engineering Theses, Dissertations, & Student Research

Tuberculosis, a highly contagious disease, ranks as the second leading cause of death from an infectious disease, and remains a major global health problem. In 2013, 9 million new cases were diagnosed and 1.5 million people died worldwide from tuberculosis. This dissertation aims at developing a new, ultrafine particle-based efficient antibiotic delivery system for the treatment of tuberculosis. The carrier material to make the rifampicin (RIF)-loaded particles is a low molecular weight star-shaped polymer produced from glucosamine (molecular core building unit) and L-lactide (GluN-LLA). Stable particles with a very high 50% drug loading capacity were made via electrohydrodynamic ...