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Alternative Routes For Purification Of Collagen Type I Α1 From A Whole Corn Extract, Christopher Michael Setina 2010 Iowa State University

Alternative Routes For Purification Of Collagen Type I Α1 From A Whole Corn Extract, Christopher Michael Setina

Graduate Theses and Dissertations

Transgenic corn is capable of producing and storing Type I α1 human collagen (r-CIα1) containing a sequence that assists assembly (foldon) and the mature cleaved form (without foldon). Extracts of ground corn grain spiked with Pichia-sourced collagen (rP-CIα1), with and without foldon, were precipitated with NaCl to purify collagen from host cell proteins. The low acid solubility of host cell proteins (HCP's) along with the acid stability of collagen favored extraction at pH 2. NaCl concentrations >0.75 M provided complete precipitation of rP-CIα1 without foldon and >70% purity. A fractional cut to remove HCP's with 0 ...


Polymer/Mesoporous Metal Oxide Composites, Melissa Ann Ver Meer 2010 Iowa State University

Polymer/Mesoporous Metal Oxide Composites, Melissa Ann Ver Meer

Graduate Theses and Dissertations

Understanding the nature of the interfacial region between an organic polymer matrix and an inorganic filler component is essential in determining how this region impacts the overall bulk properties of the organic/inorganic hybrid composite material. In this work, polystyrene was used as the model polymer matrix coupled with silica-based filler materials to investigate the nature of structure-property relationships in polymer composites.

Initial work was conducted on synthesis and characterization of colloidal and mesoporous silica particles melt blended into the polystyrene matrix. Modification of the interface was accomplished by chemically bonding the silica particles with the polystyrene chains through polymerization ...


Numerical Modeling Of Free Surface And Rapid Solidification For Simulation And Analysis Of Melt Spinning, Chunbai Wang 2010 Iowa State University

Numerical Modeling Of Free Surface And Rapid Solidification For Simulation And Analysis Of Melt Spinning, Chunbai Wang

Graduate Theses and Dissertations

The work provides methodologies for studying, designing, and optimizing melt spinning processes of fiber manufacture. Amorphous metallic materials can be created through melt spinning processes, in which a highly spinning wheel undercools a jet of molten metal or alloy below the equilibrium melting and the nucleation temperatures. Free-jet melt spinning employs a larger nozzle-wheel gap compared to planar flow casting. The instability of melt pool formation in a free-jet melt spinning will allow the variability of ribbon production. In general, a stable delivery of amorphous materials depends simultaneously on various control parameters, such as wheel speed, molten flow viscosity, surface ...


Silica Nanosphere Textured Back Reflectors For Increased Absorption In Thin Film Amorphous Silicon Solar Cells, Brian Wellington Lewis 2010 Iowa State University

Silica Nanosphere Textured Back Reflectors For Increased Absorption In Thin Film Amorphous Silicon Solar Cells, Brian Wellington Lewis

Graduate Theses and Dissertations

Absorption of long-wavelength photons in thin-film hydrogenated amorphous silicon (a-Si:H) solar cells is inherently low due to an absorption layer thickness of 250-300nm and long absorption lengths for photons of wavelengths above 700nm. When used in a thin-film solar cell, back reflectors that exhibit diffuse reflection increase the probability of absorption by lengthening the path-lengths of photons. Ordered monolayers of silica nanospheres coated with a reflective surface were investigated for use as a diffuse back reflector.

A method for fabricating a monolayer of silica nanospheres was developed using a custom built dip-coating apparatus. Repeatable monolayers of 500nm nanospheres were ...


Focussed Electric Field Induced Ion Transport: A Novel Nano-Patterning Process, Dibyadeep Paul 2010 Iowa State University

Focussed Electric Field Induced Ion Transport: A Novel Nano-Patterning Process, Dibyadeep Paul

Graduate Theses and Dissertations

FEFIIT is a unique method, which can be utilized to imprint complex structures on the surface of a conducting substrate. Experimental results have shown that under certain conditions, it is possible to obtain surface structures with characteristic length smaller than that of the mask. DC chopped simulations in particular yield unique features, which can be exploited to yield high aspect ratio structures. In this thesis, a model of this process is established and studied. Studies are conducted on the various length scale parameters as well as the starting concentration, and the potential applied. Two independent dimensionless parameters are found to ...


Experimental Study Of Inhomogeneous Deformation In Bulk Metallic Glass And Their Composite During Wedge-Like Cylindrical Indentation, Hui Wang 2010 Iowa State University

Experimental Study Of Inhomogeneous Deformation In Bulk Metallic Glass And Their Composite During Wedge-Like Cylindrical Indentation, Hui Wang

Graduate Theses and Dissertations

Bulk metallic glasses (BMGs) are amorphous metals with impressive mechanical properties, such as high elastic strain up to 2%, high strength (up to 2% of Young's modulus) and high hardness. Their weight normalized properties exceed the high strength to weight ratio of titanium alloys. Because of the lack of crystalline defects such as grain boundaries and dislocations, they have good corrosion resistance and good formability. The unique die molding properties of BMGs render them as excellent candidates for micro-scale machine parts, pressure sensor, golf clubs and casings. BMG's also exhibit enhanced plastic creep resistance, since homogeneous plastic deformation ...


Seismic Performance Of An I-Girder To Inverted-T Bent Cap Bridge Connection, Richard Manning Snyder 2010 Iowa State University

Seismic Performance Of An I-Girder To Inverted-T Bent Cap Bridge Connection, Richard Manning Snyder

Graduate Theses and Dissertations

This thesis represents a portion of the research conducted as part of an investigation for the California Department of Transportation (Caltrans) regarding the seismic response and overall moment capacity of precast I-girder to inverted-T bent cap bridge connections for seismic applications. The current design practice, as outlined by Caltrans' Seismic Design Criteria, assumes that the connection between the precast I-girders and the inverted-T bent cap will degrade in a seismic event and shall therefore be designed as a pinned connection, making the precast girder option for seismic bridges inefficient. A prototype I-girder to inverted-T bent cap bridge and a 50 ...


Devitrification Kinetics And Phase Selection Mechanisms In Cu-Zr Metallic Glasses, Ilkay Kalay 2010 Iowa State University

Devitrification Kinetics And Phase Selection Mechanisms In Cu-Zr Metallic Glasses, Ilkay Kalay

Graduate Theses and Dissertations

Metallic glasses have been a promising class of materials since their discovery in the 1960s. Indeed, remarkable chemical, mechanical and physical properties have attracted considerable attention, and several excellent reviews are available. Moreover, the special group of glass forming alloys known as the bulk metallic glasses (BMG) become amorphous solids even at relatively low cooling rates, allowing them to be cast in large cross sections, opening the scope of potential applications to include bulk forms and net shape structural applications. Recent studies have been reported for new bulk metallic glasses produced with lower cooling rates, from 0.1 to several ...


Reducing Phase Noise Degradation Due To Vibration Of Crystal Oscillators, Cory Nelson 2010 Iowa State University

Reducing Phase Noise Degradation Due To Vibration Of Crystal Oscillators, Cory Nelson

Graduate Theses and Dissertations

In the radio communications industry, one major problem is the vibration induced on to a frequency standard. The most commonly used frequency standard is the crystal oscillator; as the crystal oscillator gets vibrated with varying force and frequencies of vibration the phase noise of the signal changes. As the phase noise increases, the signal to noise ratio decreases causing the likelihood of transmitting or receiving an incorrect signal to rise. This makes it critical to limit the phase noise increase that occurs in the frequency standard of the system.

Mechanical isolation systems have been implemented in the industry to limit ...


Medium Access Control And Network Planning In Wireless Networks, Zakhia Abichar 2010 Iowa State University

Medium Access Control And Network Planning In Wireless Networks, Zakhia Abichar

Graduate Theses and Dissertations

Wireless Local Area Networks (WLANs) and Wireless Metropolitan Area Networks (WMANs) are two of the main technologies in wireless data networks. WLANs have a short range and aim at providing connectivity to end users. On the other hand, WMANs have a long range and aim at serving as a backbone network and also at serving end users. In this dissertation, we consider the problem of Medium Access Control (MAC) in WLANs and the placement of Relay Stations (RSs) in WMANs. We propose a MAC scheme for WLANs in which stations contend by using jams on the channel. We present analytic ...


Molecular Dynamics Simulations On The Inhibition Of Methane Hydrates, Zhiju Zheng 2010 Iowa State University

Molecular Dynamics Simulations On The Inhibition Of Methane Hydrates, Zhiju Zheng

Graduate Theses and Dissertations

We study the effect of a specific hyperbranched poly(ester amide)s on the growth of the methane hydrate with atomistic molecular dynamics simulation. The growth of methane hydrates was modeled as a solid/liquid system containing a slab of hydrate crystallite and a liquid methane/water mixture. We modeled the effects of two versions of this molecular system, either the core structure (H400) or a full sized version molecule (H1500), to examine whether the molecular weight of inhibitors affect the growth of the hydrate. Radial distribution functions for carbon atoms of methane molecules are employed to examine the growth ...


A Plug And Play Framework For An Hvac Air Handling Unit And Temperature Sensor Auto Recognition Technique, Xiaohui Zhou 2010 Iowa State University

A Plug And Play Framework For An Hvac Air Handling Unit And Temperature Sensor Auto Recognition Technique, Xiaohui Zhou

Graduate Theses and Dissertations

A plug and play framework for an HVAC air handling unit control system is proposed in this study. This is the foundation and the first step towards the plug and play HVAC control system that will eventually lead to self-configuring of HVAC control systems for automatic building controls system set-up, commissioning, more robust HVAC system operations, and automatic detection and repair of potential controls problems. This framework is built on the commercially available smart transducers that are compatible with the IEEE 1451 family of standards, and a data acquisition system that can read and write the smart transducer information. As ...


Smart Maintenance Decision Support Systems (Smdss), Daniel Paul Bumblauskas 2010 Iowa State University

Smart Maintenance Decision Support Systems (Smdss), Daniel Paul Bumblauskas

Graduate Theses and Dissertations

Computerized information systems are used in all contemporary industries and have been applied to track maintenance information and history. To a lesser extent, such information systems have also been used to predict or simulate maintenance decisions and actions. This work details two models, a population data analysis, and a system infrastructure, to aid operations and maintenance managers with the difficult resource allocation decisions they face in the field. The first model addresses the consideration of component dependency for series network connections using a Markov Decision Process model and solution algorithm. The second model addresses the prioritization of maintenance activities for ...


Instrumentation And Monitoring Of An Integral Abutment Bridge Supported On Hp-Steel Piles/Concrete Drilled Shafts, Ashley Elizabeth Cook 2010 Iowa State University

Instrumentation And Monitoring Of An Integral Abutment Bridge Supported On Hp-Steel Piles/Concrete Drilled Shafts, Ashley Elizabeth Cook

Graduate Theses and Dissertations

The topic of integral abutment bridges has been of interest for the Iowa Department of Transportation for the past few decades. One specific bridge design implementing an integral abutment supported on HP-steel piles embedded in concrete drilled shafts was utilized on the 9th Street Bridge in Des Moines, Iowa and is the topic of this study. The primary objective of this study was to monitor the bridge behavior over a two year period in order to better understand the bridge behavior. In order to satisfy the objectives of this study, a literature review was performed, a monitoring system was developed ...


Effect Of Heat Generation From Cement Hydration On Mass Concrete Placement, Soo Geun Kim 2010 Iowa State University

Effect Of Heat Generation From Cement Hydration On Mass Concrete Placement, Soo Geun Kim

Graduate Theses and Dissertations

Construction of a concrete dam requires large volume of concrete. Due to the small surface area-to-volume ratio, concrete dams are often subjected to high potential of thermal cracking, caused by the heat generation from cement hydration. To reduce the thermal cracking and ensure dam structure safety, a concrete dam is often constructed with low heat-generating cement and separated blocks having relative thin lift thickness. In Korea, low heat Type IV has been mainly used to reduce the temperature rise. Although benefits of using supplementary cementitious materials (SCMs) in concrete have been recognized, the practice of SCMs in dam concrete is ...


Dislocation Dynamics Simulations Of Plasticity At Small Scales, Caizhi Zhou 2010 Iowa State University

Dislocation Dynamics Simulations Of Plasticity At Small Scales, Caizhi Zhou

Graduate Theses and Dissertations

As metallic structures and devices are being created on a dimension comparable to the length scales of the underlying dislocation microstructures, the mechanical properties of them change drastically. Since such small structures are increasingly common in modern technologies, there is an emergent need to understand the critical roles of elasticity, plasticity, and fracture in small structures. Dislocation dynamics (DD) simulations, in which the dislocations are the simulated entities, offer a way to extend length scales beyond those of atomistic simulations and the results from DD simulations can be directly compared with the micromechanical tests.

The primary objective of this research ...


Issures In Discontinuous High-Order Methods: Broadband Wave Computation And Viscous Boundary Layer Resolution, Yi Li 2010 Iowa State University

Issures In Discontinuous High-Order Methods: Broadband Wave Computation And Viscous Boundary Layer Resolution, Yi Li

Graduate Theses and Dissertations

A new discontinuous formulation named Correction Procedure via Reconstruction (CPR) was developed for conservation laws. CPR is an efficient nodal differential formulation unifying the discontinuous Galerkin (DG), spectral volume (SV) and spectral difference (SD) methods, is easy to implement. In this thesis, we deal with two issues: the efficient computation of broadband waves, and the proper resolution of a viscous boundary layer with the high-order CPR method.

A hybrid discontinuous space including polynomial and Fourier bases is employed in the CPR formulation in order to compute broad-band waves. The polynomial bases are used to achieve a certain order of accuracy ...


Discrete Element Simulations And Constitutive Modeling Of Dense Granular Flows, Vidyapati Vidyapati 2010 Iowa State University

Discrete Element Simulations And Constitutive Modeling Of Dense Granular Flows, Vidyapati Vidyapati

Graduate Theses and Dissertations

The aim of this study is to understand and explore the rheology of

dense granular flow, in particular the phenomenon of regime

transition, using both microscale DEM (discrete element method)

simulations and macroscale modeling methods. The rheology of dense sheared granular flow in a Couette device is simulated using DEM. It is found that DEM simulations are capable of capturing the regime transition from quasi-static to intermediate behavior. A constitutive model based on the order parameter (OP) framework is refined, and a linear model with new model coefficients extracted from data of 3D DEM simulations of homogeneously sheared granular flows ...


Thixotropic Behavior Of Cement-Based Materials: Effect Of Clay And Cement Types, Zhuojun Quanji 2010 Iowa State University

Thixotropic Behavior Of Cement-Based Materials: Effect Of Clay And Cement Types, Zhuojun Quanji

Graduate Theses and Dissertations

In this thesis, effects of clay addition, clay replacement, and cement types on thixotropic behavior of cement-based materials are investigated.

Thixotropy is the property of certain fluid materials that are thick or viscous under normal conditions but flow or become less viscous over time when shaken, agitated, or otherwise stressed. Freshly-mixed cement pastes are thixotropic materials, which become fluid when agitated but restore its structural form at rest. This is because cement pastes experience microstructure change with time due to the particles flocculation and cement hydration.

The thixotropic behavior of cement-based materials is important in the modern concrete construction. Shape ...


Performance Of A Pilot Scale Biomass Gasification And Producer Gas Combustion System Using Feedstock With Controlled Nitrogen Content, Sharan Sethuraman 2010 Iowa State University

Performance Of A Pilot Scale Biomass Gasification And Producer Gas Combustion System Using Feedstock With Controlled Nitrogen Content, Sharan Sethuraman

Graduate Theses and Dissertations

This study is focused on the effects of nitrogen content in biomass feedstock on the producer gas composition and the flue gas NOx emissions from a pilot-scale gasification and combustion system. Biomass gasification has the potential to produce carbon negative

energy by using renewable resources. The greenhouse gases emitted by burning fossil fuels have to be reduced, and biomass gasification is one of the means to achieving this. When the biomass-derived gas is burned, NOx emissions are a critical factor that can limit the use of the system. The government regulations limit the amount of NOx that can be emitted ...


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