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2006

Iowa State University

Engineering

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Synthesis And Characterization Of Hydrated Rubidium Thio-Hydroxosilicogermanates Using Mechanochemical Hydrothermal Synthesis, Carly R. Nelson, Sarah Olson, Steven A. Poling, Steve W. Martin Dec 2006

Synthesis And Characterization Of Hydrated Rubidium Thio-Hydroxosilicogermanates Using Mechanochemical Hydrothermal Synthesis, Carly R. Nelson, Sarah Olson, Steven A. Poling, Steve W. Martin

Materials Science and Engineering Publications

The synthesis, structure, and proton conductivity of the hydrated thio-hydroxosilicogermanates RbzGexSi1-xSz(OH)4-z·yH2O (2 ≤ z ≤ 3; 0 < y < 1.7) are reported. X-ray diffraction indicates that the z = 2 materials are amorphous and show no unreacted starting materials, which is consistent with the mechanochemical hydrothermal evaporation−precipitation synthesis method. Infrared spectroscopy shows a fully reacted system where both silicon and germanium central anions have vibrational modes at 950, 780, 667, and 450 cm-1 associated with asymmetric modes for Si−O, Ge−O, Si−S, and Ge−S chemical bonds, respectively. O−H stretching and bending modes are present at ...


Carbon Monoxide Mass Transfer In A Syngas Mixture, Amir Kapic, Samuel T. Jones, Theodore J. Heindel Dec 2006

Carbon Monoxide Mass Transfer In A Syngas Mixture, Amir Kapic, Samuel T. Jones, Theodore J. Heindel

Mechanical Engineering Publications

A myoglobin assay for measuring concentrations of dissolved carbon monoxide (CO) from an artificial synthesis gas blend (20% CO, 18% CO2, 52% N2, and 10% H2) was utilized to determine volumetric CO−water mass-transfer rates in a 0.211-m-diameter stirred-tank reactor (STR). The data are well correlated using the power density and superficial gas velocity, but this correlation is valid only for this STR size. A gas−liquid scale-up model developed for dissolved oxygen mass-transfer rates using air was used to develop a CO−liquid scale-up model for syngas fermentation. The model is applicable in the STR hydrodynamic range associated ...


Dynamics And Structures Of Segregation In A Dense, Vibrating Granular Bed, Jin Sun, Francine Battaglia, Shankar Subramaniam Dec 2006

Dynamics And Structures Of Segregation In A Dense, Vibrating Granular Bed, Jin Sun, Francine Battaglia, Shankar Subramaniam

Mechanical Engineering Publications

We study the rise dynamics of a large particle in a granular bed under vertical vibration using molecular dynamics simulations. Systematic variation of the particle properties and external wall friction in the simulations shows that the large particle rising is very sensitive to external wall friction. The dynamical response of the granular bed with wall friction is shown to include an expansion stage and a compression stage within one cycle. With wall friction, large-scale force networks bearing larger-than-average forces are found in the compression stage. However, without wall friction, large strong force networks do not exist. The distribution of normal ...


High-Resolution, Real-Time Three-Dimensional Shape Measurement, Song Zhang, Peisen S. Huang Dec 2006

High-Resolution, Real-Time Three-Dimensional Shape Measurement, Song Zhang, Peisen S. Huang

Song Zhang

We describe a high-resolution, real-time 3-D shape measurement system based on a digital fringe projection and phase-shifting technique. It utilizes a single-chip digital light processing projector to project computer-generated fringe patterns onto the object, and a high-speed CCD camera synchronized with the projector to acquire the fringe images at a frame rate of 120frames∕s. A color CCD camera is also used to capture images for texture mapping. Based on a three-step phase-shifting technique, each frame of the 3-D shape is reconstructed using three consecutive fringe images. Therefore the 3-D data acquisition speed of the system is 40frames∕s. With ...


Modeling Of The Size Effects On The Behavior Of Metals In Microscale Deformation Processes, Gap-Yong Kim, Jun Ni, Muammer Koc Dec 2006

Modeling Of The Size Effects On The Behavior Of Metals In Microscale Deformation Processes, Gap-Yong Kim, Jun Ni, Muammer Koc

Gap-Yong Kim

For the accurate analysis and design of microforming process, proper modeling of material behavior at the micro/mesoscale is necessary by considering the size effects. Two size effects are known to exist in metallic materials. One is the “grain size” effect, and the other is the “feature/specimen size” effect. This study investigated the feature/specimen size effect and introduced a scaling model which combined both feature/specimen and grain size effects. Predicted size effects were compared with three separate experiments obtained from previous research: a simple compression with a round specimen, a simple tension with a round specimen, and ...


Effect Of Chain Architecture And Surface Energies On The Ordering Behavior Of Lamellar And Cylinder Forming Block Copolymers, V. Khanna, Eric W. Cochran, A. Hexemer, G. E. Stein, G. H. Fredrickson, E. J. Kramer, X. Li, J. Wang, S. F. Hahn Dec 2006

Effect Of Chain Architecture And Surface Energies On The Ordering Behavior Of Lamellar And Cylinder Forming Block Copolymers, V. Khanna, Eric W. Cochran, A. Hexemer, G. E. Stein, G. H. Fredrickson, E. J. Kramer, X. Li, J. Wang, S. F. Hahn

Eric W. Cochran

We investigate the effect of surface energy and chain architecture on the orientation of microdomains in relatively thick films (600-800 nm) of lamellar and cylindrical block copolymers of poly(cyclohexylethylene) (C) and poly(ethylene) (E). The E block has 26 ethyl branches per 1000 backbone carbon atoms. Melt surface energies of the C and E blocks are 22.3 and 20.9 mJ/m 2, respectively. Grazing-incidence small-angle X-ray scattering (GISAXS), scanning force microscopy (SFM), and cross-sectional transmission electron microscopy (TEM) show that cylindrical and lamellar CEC triblock copolymers orient their microdomains normal to the surface throughout the film thickness ...


Potential Benefits Of Wetland Filters For Tile Drainage Systems: Impact On Nitrate Loads To Mississippi River Subbasins, William G. Crumpton, Greg A. Stenback, Bradley Allen Miller, Matt Helmers Dec 2006

Potential Benefits Of Wetland Filters For Tile Drainage Systems: Impact On Nitrate Loads To Mississippi River Subbasins, William G. Crumpton, Greg A. Stenback, Bradley Allen Miller, Matt Helmers

Ecology, Evolution and Organismal Biology Reports

The primary objective of this project was to estimate the nitrate reduction that could be achieved using restored wetlands as nitrogen sinks in tile-drained regions of the upper Mississippi River (UMR) and Ohio River basins. This report provides an assessment of nitrate concentrations and loads across the UMR and Ohio River basins and the mass reduction of nitrate loading that could be achieved using wetlands to intercept nonpoint source nitrate loads. Nitrate concentration and stream discharge data were used to calculate stream nitrate loading and annual flow-weighted average (FWA) nitrate concentrations and to develop a model of FWA nitrate concentration ...


Potential Benefits Of Wetland Filters For Tile Drainage Systems: Impact On Nitrate Loads To Mississippi River Subbasins, William G. Crumpton, Greg A. Stenback, B. A. Miller, Matthew J. Helmers Dec 2006

Potential Benefits Of Wetland Filters For Tile Drainage Systems: Impact On Nitrate Loads To Mississippi River Subbasins, William G. Crumpton, Greg A. Stenback, B. A. Miller, Matthew J. Helmers

Agricultural and Biosystems Engineering Technical Reports and White Papers

The primary objective of this project was to estimate the nitrate reduction that could be achieved using restored wetlands as nitrogen sinks in tile-drained regions of the upper Mississippi River (UMR) and Ohio River basins. This report provides an assessment of nitrate concentrations and loads across the UMR and Ohio River basins and the mass reduction of nitrate loading that could be achieved using wetlands to intercept nonpoint source nitrate loads. Nitrate concentration and stream discharge data were used to calculate stream nitrate loading and annual flow-weighted average (FWA) nitrate concentrations and to develop a model of FWA nitrate concentration ...


Disaster Recovery—Managing Immature Crops For Grain Or Silage, Stephen K. Barnhart, Roger W. Elmore, Palle Pedersen, H. Mark Hanna Dec 2006

Disaster Recovery—Managing Immature Crops For Grain Or Silage, Stephen K. Barnhart, Roger W. Elmore, Palle Pedersen, H. Mark Hanna

Agriculture and Environment Extension Publications

Tips on managing crops that may not mature before the first killing freeze of fall.


An Ultrasonic Array Sensor For Spacecraft Leak Direction Finding, Stephen D. Holland, Ronald A. Roberts, Dale E. Chimenti, Junho Song Dec 2006

An Ultrasonic Array Sensor For Spacecraft Leak Direction Finding, Stephen D. Holland, Ronald A. Roberts, Dale E. Chimenti, Junho Song

Aerospace Engineering Publications

We have developed an ultrasonic array sensor useable for locating air leaks in manned spacecraft and have found that this sensor locates leaks in a 1-m2 plate to within 2 cm. The sensor consists of a 63-element multiplexed array plus a reference element, all constructed from a single PZT disc and a printed circuit board. Cross-correlations of signals from the array elements with signals from the single reference element provide a measurement of the leak noise passing through the spacecraft skin under the array. A spatial Fourier transform reveals the dominant direction of propagation. Triangulation from multiple sensor locations ...


Spray Equipment Selection For Best Protection Against Soybean Rust And Aphid, Erdal Ozkan Nov 2006

Spray Equipment Selection For Best Protection Against Soybean Rust And Aphid, Erdal Ozkan

Proceedings of the Integrated Crop Management Conference

Fungicides manufactured to control soybean rust are effective; however, successful control of this disease will mostly depend on proper application methods. Spray coverage and deposition from 9 application equipment/spray nozzles were analyzed. In general, the spray treatments with air assistance were more effective in spraying rust fungicides than the treatments with the conventional boom sprayer. Spray performances from the boom sprayer with a canopy opener were very similar to the air assisted spray treatments, and were better than other treatments with the boom sprayer. Twinjet, Turbo Dual pattern and hollow cone nozzles produced lower spray performances than single-flow pattern ...


Sourcing Corn For Ethanol: Effects Of Increased Local Processing, Connie L. Hardy, Howard E. Shepherd, Charles R. Hurburgh Jr., Mary S. Holz-Clause Nov 2006

Sourcing Corn For Ethanol: Effects Of Increased Local Processing, Connie L. Hardy, Howard E. Shepherd, Charles R. Hurburgh Jr., Mary S. Holz-Clause

Proceedings of the Integrated Crop Management Conference

Rapid growth of ethanol production continues to generate many questions related to future analysis, shifts in existing businesses and policy development. In Iowa, new dry-grind ethanol processing plant construction is announced frequently, financed by either local or remote investor groups. New dry-grind ethanol plants are also being added to existing wet milling operations. As these markets develop, there will be innovation in contracts, price discovery and market information. There will also be changes to supplier interaction and service aspects as well. One of the growing concerns is the balance of corn supplies between new ethanol demand and existing feed/export ...


Economic And Environmental Considerations For Drainage Design, Matthew J. Helmers, Ranvir Singh Nov 2006

Economic And Environmental Considerations For Drainage Design, Matthew J. Helmers, Ranvir Singh

Proceedings of the Integrated Crop Management Conference

Water table management through the use of artificial subsurface drainage systems is of primary importance in humid areas with poorly or somewhat poorly drained soils to maximize agricultural productivity Excess precipitation in Iowa and many other Mississippi/Ohio River watershed agricultural production states is removed artificially via subsurface drainage systems that intercept and usually divert it to surface waters. Subsurface drainage systems have been installed to allow timely seedbed preparation, planting and harvesting and to protect crops from extended periods of flooded soil conditions. The tradeoff of improved subsurface drainage is a significant increase in the losses of nitrate-nitrogen (Gilliam ...


Foliar Fungicide Application Techniques On Soybeans, H. Mark Hanna, Alison Robertson, W. Mark Carlton, Robert E. Wolf Nov 2006

Foliar Fungicide Application Techniques On Soybeans, H. Mark Hanna, Alison Robertson, W. Mark Carlton, Robert E. Wolf

Proceedings of the Integrated Crop Management Conference

Soybeans (Glycine max L.) are a major commodity crop grown on over 29 million hectare (72 million acres) in the United States. A large part of the cropland base in Iowa, 5 million hectare (11 to 13 million acres) annually, is devoted to soybean production. Although long term crop yield trends are upward, soybean yield increases have been more stagnant than corn, the common companion rotational crop, causing growers to question factors such as disease that might be slowing yield growth. In late 2004 Asian Soybean Rust (Phahopsora pachyrhizi) was detected in the United States. Because of the potential for ...


Ethanol Webcast Archived Online, Jean Mcguire Nov 2006

Ethanol Webcast Archived Online, Jean Mcguire

Integrated Crop Management News

The Perspectives on Present and Future Corn-Based Ethanol Industry webcast was presented by Iowa State University (ISU) Extension on Monday, November 13. An archive of the program is available athttp://www.extension.iastate.edu/webcast/archive.htm. Seven Iowa State University economists presented economic information on several aspects of the industry during the 3-hour, 15-minute program. Links to papers offering additional information on each topic and the PowerPoint each presenter used are available at http://www.extension.iastate.edu/ag/ethanol.html.


Elastic Properties Of Gd5si2ge2 Studied With An Ultrasonic Pulse-Echo Technique, O. Svitelskiy, A. Suslov, Deborah L. Schlagel, Thomas A. Lograsso, Karl A. Gschneidner Jr., Vitalij K. Pecharsky Nov 2006

Elastic Properties Of Gd5si2ge2 Studied With An Ultrasonic Pulse-Echo Technique, O. Svitelskiy, A. Suslov, Deborah L. Schlagel, Thomas A. Lograsso, Karl A. Gschneidner Jr., Vitalij K. Pecharsky

Ames Laboratory Publications

We present the results of a study of the elastic properties of Gd5Si2Ge2, an alloy with giant magnetocaloric, magnetostrictive, and colossal magnetoresistive properties. Sound wave velocities measured in a number of different geometries allowed us to determine the whole elastic tensor for the monoclinic phase of this material. The anisotropy of the crystal is explored using the polar plots of the variations in the main crystallographic planes of the sound speed, the Young’s modulus, the shear modulus, and the linear compressibility. The effect of hydrostatic pressure on the Gd5Si2Ge2 ...


An Integrated Systems Approach To The Development Of Winter Maintenance / Management Systems, James S. Noble, Wooseung Jang, Cerry M. Klein, Charles J. Nemmers Nov 2006

An Integrated Systems Approach To The Development Of Winter Maintenance / Management Systems, James S. Noble, Wooseung Jang, Cerry M. Klein, Charles J. Nemmers

InTrans Project Reports

Winter road maintenance operations require many complex strategic and operational planning decisions. The five primary problems involved in this intricate planning procedure include locating depots, designing sectors, routing service vehicles, scheduling vehicles, and configuring the vehicle fleet. The complexity involved in each of these decisions has resulted mainly in research that approaches each of the problems separately and sequentially, which can lead to isolated and suboptimal solutions. After discussing the complexity of the relaxed subproblems that would need to be solved to optimize the intricate winter maintenance operations, the research turns to a heuristic approach to more feasibly address the ...


Posterminaries: After Nabarro, Alexander H. King Nov 2006

Posterminaries: After Nabarro, Alexander H. King

Alexander H. King

With the passing of Frank Nabarro in July of this year, we have lost one of the founding fathers of materials science. His name appears in many of the textbooks from which we train our students today, and also on the spines of several volumes on dislocation theory, including his classic monograph on the subject. He rightly stands among the gods of our field. Ninety years old at his death, he was a sprightly dancer at the frontiers of knowledge, right up to the end.


Numerical Simulations Of Gas-Liquid Flow Dynamics In Bubble Columns, Deify Law, Francine Battaglia, Theodore J. Heindel Nov 2006

Numerical Simulations Of Gas-Liquid Flow Dynamics In Bubble Columns, Deify Law, Francine Battaglia, Theodore J. Heindel

Mechanical Engineering Conference Presentations, Papers, and Proceedings

There is great potential for using computational fluid dynamics (CFD) as a tool in scale-up and design of bubble columns. Full-scale experimentation in bubble columns is expensive and CFD is an alternative approach to study bubble column hydrodynamics. However, CFD can be computationally intensive as a predictive tool for a full three-dimensional geometry. In this paper, a 0.2 m diameter semi-batch bubble column is numerically simulated and the results are compared to experimental measurements performed by Rampure et al. [1]. The objectives are to examine and determine an appropriate set of numerical parameters and to determine if two-dimensional simulations ...


Characterization Of Volatile Organic Compounds And Odors By In-Vivo Sampling Of Beef Cattle Rumen Gas, By Solid-Phase Microextraction, And Gas Chromatography–Mass Spectrometry–Olfactometry, Lingshuang Cai, Jacek A. Koziel, Jeremiah Davis, Yin-Cheung Lo, Hongwei Xin Nov 2006

Characterization Of Volatile Organic Compounds And Odors By In-Vivo Sampling Of Beef Cattle Rumen Gas, By Solid-Phase Microextraction, And Gas Chromatography–Mass Spectrometry–Olfactometry, Lingshuang Cai, Jacek A. Koziel, Jeremiah Davis, Yin-Cheung Lo, Hongwei Xin

Agricultural and Biosystems Engineering Publications

Volatile organic compounds (VOCs) and odors in cattle rumen gas have been characterized by in-vivo headspace sampling by solid-phase microextraction (SPME) and analysis by gas chromatography–mass spectrometry–olfactometry (GC–MS–O). A novel device enabling headspace SPME (HS-SPME) sampling through a cannula was designed, refined, and used to collect rumen gas samples from steers. A Carboxen–polydimethylsiloxane (PDMS) fiber (85 μm) was used for SPME sampling. Fifty VOCs from ten chemical groups were identified in the rumen headspace. The VOCs identified had a wide range of molecular weight (MW) (34 to 184), boiling point (−63.3 to 292 °C ...


Modeling Of The Semi-Solid Material Behavior And Analysis Of Micro-/Mesoscale Feature Forming, Gap-Yong Kim, Muammer Koc, Rhet Mayor, Jun Ni Oct 2006

Modeling Of The Semi-Solid Material Behavior And Analysis Of Micro-/Mesoscale Feature Forming, Gap-Yong Kim, Muammer Koc, Rhet Mayor, Jun Ni

Gap-Yong Kim

One of the major challenges in simulation of semi-solid forming is characterizing the complex behavior of a material that consists of both solid and liquid phases. In this study, a material model for an A356 alloy in a semi-solid state has been developed for high solid fractions (>0.6) and implemented into a finite element simulation tool to investigate the micro-/mesoscale feature formation during the forming process. Compared to previous stress models, which are limited to expressing the stress dependency on only the strain rate and the temperature (or the solid fraction), the proposed stress model adds the capability ...


Analytical And Experimental Studies Of Properties Of Ethanol Coproduct-Filled Plastics, Robert Tatara, Andrew Otieno, Srikrishna Suraparaju, Kurt A. Rosentrater Oct 2006

Analytical And Experimental Studies Of Properties Of Ethanol Coproduct-Filled Plastics, Robert Tatara, Andrew Otieno, Srikrishna Suraparaju, Kurt A. Rosentrater

Kurt A. Rosentrater

As the renewable fuels industry continues to grow, the quantity of resulting byproducts has expanded in tandem. Currently, these materials are primarily used for animal feed, but at some point will saturate the animal feeds market. Thus, it is necessary to investigate alternative methods and applications by which these coproducts can be utilized. One potential application for these process residues involves plastics manufacturing. Due, in part, to the increasing cost of resins and conventional fillers, alternate fillers have been increasingly sought. Many of these include biological materials such as grasses, bamboo, starch, chicken feathers, soy protein, and cellulose. Not only ...


The Importance Of Emerging Biobased Industries To Engineering And Technology, Kurt A. Rosentrater, R. Balamuralikrishma Oct 2006

The Importance Of Emerging Biobased Industries To Engineering And Technology, Kurt A. Rosentrater, R. Balamuralikrishma

Kurt A. Rosentrater

Our society has developed an insatiable demand for energy and material goods. Historically, these needs have been met primarily by fossil fuels and other non-renewable raw materials. As environmental concerns grow, however, renewable resources are gaining increased attention. This paper examines the emergence and importance that biobased industries are increasingly beginning to play. A biobased enterprise, similar in concept to a traditional refinery or factory, utilizes conversion technologies to produce various products. These operations are rapidly increasing both in number as well as in capacity throughout this country, and are poised to add significantly to the nation’s energy and ...


Mass Customization And Its Curricular Implications For Four-Year Degree Programs In Manufacturing Technologies, R. Balamuralikrishma, Kurt A. Rosentrater, Mark Rajai Oct 2006

Mass Customization And Its Curricular Implications For Four-Year Degree Programs In Manufacturing Technologies, R. Balamuralikrishma, Kurt A. Rosentrater, Mark Rajai

Kurt A. Rosentrater

Mass customization is fast emerging as a popular business strategy which aims to also cater to individual expressed needs of end users at prices closely comparable to mass produced items. Companies are able to switch to this mode of operation by primarily making their own operations demand-driven, flexible systems and asking their suppliers to do the same. Customers by and large are delighted to be part of this new kind of supply chain and are willing to invest time to specify what exactly they want provided businesses are willing to keep their end of the bargain in terms of high ...


Extraction Of Recombinant Dog Gastric Lipase From Transgenic Corn Seed, Qixin Zhong, Zhengrong Gu, Charles E. Glatz Oct 2006

Extraction Of Recombinant Dog Gastric Lipase From Transgenic Corn Seed, Qixin Zhong, Zhengrong Gu, Charles E. Glatz

Chemical and Biological Engineering Publications

Several approaches were examined for extracting the relatively hydrophobic protein recombinant dog gastric lipase (rDGL) expressed in the endosperm of transgenic corn seed. The first approach used minimal processing of the seed before extraction (i.e. simple grinding of whole seed) followed by selective extraction to eliminate 72% of contaminant proteins without compromising rDGL recovery from the meal of whole grain. The second approach added defatting of the whole grain meal to reduce the amount of detergent in the subsequent step for extracting rDGL. The third approach incorporated dry-milling of the corn to recover an endosperm rich fraction, followed by ...


An Experimental Investigation On Semi-Solid Forming Of Micro/Meso-Scale Features, Gap-Yong Kim, Jun Ni, Rhett Mayor, Heesool Kim Oct 2006

An Experimental Investigation On Semi-Solid Forming Of Micro/Meso-Scale Features, Gap-Yong Kim, Jun Ni, Rhett Mayor, Heesool Kim

Gap-Yong Kim

The potentials of semi-solid forming technology have generated much interest regarding its application in micromanufacturing. This study investigates the feasibility of using semi-solid forming technology to produce parts with micro/meso features. An experimental setup has been developed to study the effects of die/punch temperature, initial solid fraction, punch speed, and workpiece shape on the semi-solid forming process. A part has been produced for a microreactor application and has been analyzed with an optical measurement system for feature formation. The results indicated complex interaction among the process parameters and the material flow, which affected the final pin formation. The ...


Grain Quality And Handling Issues For 2006, Charles R. Hurburgh Oct 2006

Grain Quality And Handling Issues For 2006, Charles R. Hurburgh

Integrated Crop Management News

The erratic rainfall patterns across Iowa have affected both yield and quality for corn and soybeans. Because more corn is likely to be stored for local use through the entire crop year, attention to harvest and storage management details will be very important.


Method Of Making Active Magnetic Refrigerant Materials Based On Gd-Si-Ge Alloys, Alexandra O. Pecharsky, Karl A. Gschneidner Jr., Vitalij K. Pecharsky Oct 2006

Method Of Making Active Magnetic Refrigerant Materials Based On Gd-Si-Ge Alloys, Alexandra O. Pecharsky, Karl A. Gschneidner Jr., Vitalij K. Pecharsky

Iowa State University Patents

An alloy made of heat treated material represented by Gd5(SixGe1−x)4 where 0.47≦x≦0.56 that exhibits a magnetic entropy change (−ΔSm) of at least 16 J/kg K, a magnetostriction of at least 2000 parts per million, and a magnetoresistance of at least 5 percent at a temperature of about 300K and below, and method of heat treating the material between 800 to 1600 degrees C. for a time to this end.


Phase Field Theory Of Surface- And Size-Induced Microstructures, Valery I. Levitas, D.W. Lee, D. L. Preston Oct 2006

Phase Field Theory Of Surface- And Size-Induced Microstructures, Valery I. Levitas, D.W. Lee, D. L. Preston

Valery I. Levitas

New surface- and size-induced microstructures are found as analytic solutions to a phase field theory of first-order phase transformations. A recently developed exact stability criterion, based on most destabilizing fluctuations, is used to analyze the stability and physical interpretation of each microstructure. Conditions for barrierless surface nucleation, i.e. relationship between surface energy, driving force for the transformation and sample size, are found. If they are met, some of these microstructures are destroyed resulting in the barrierless transformation to alternative phases.


Semicrystalline Thermoplastic Elastomeric Polyolefins: Advances Through Catalyst Development And Macromolecular Design, Atsushi Hotta, Eric W. Cochran, Janne Ruokolainen, Vikram Khann, Glenn H. Fredrickson, Edward J. Kramer, Yong-Woo Shin, Fumihiko Shimizu, Anna E. Cherian, Phillip D. Hustad, Jeffrey M. Rose, Geoffrey W. Coates Oct 2006

Semicrystalline Thermoplastic Elastomeric Polyolefins: Advances Through Catalyst Development And Macromolecular Design, Atsushi Hotta, Eric W. Cochran, Janne Ruokolainen, Vikram Khann, Glenn H. Fredrickson, Edward J. Kramer, Yong-Woo Shin, Fumihiko Shimizu, Anna E. Cherian, Phillip D. Hustad, Jeffrey M. Rose, Geoffrey W. Coates

Eric W. Cochran

We report the design, synthesis, morphology, phase behavior, and mechanical properties of semicrystalline, polyolefin-based block copolymers. By using living, stereoselective insertion polymerization catalysts, syndiotactic polypropylene-block-poly(ethylene-co-propylene)-block-syndiotactic polypropylene and isotactic poly propylene-block-regioirregular poly propylene-block- isotactic polypropylene triblock copolymers were synthesized. The volume fraction and composition of the blocks, as well as the overall size of the macromolecules, were controlled by sequential synthesis of each block of the polymers. These triblock copolymers, with semicrystalline end-blocks and mid-segments with low glass-transition temperatures, show significant potential as thermoplastic elastomers. They have low Young's moduli, large strains at break, and better than 90 ...