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Iowa State University

2005

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Articles 1 - 30 of 56

Full-Text Articles in Engineering

Quantitative Elucidation Of A Distinct Spatial Gradient-Sensing Mechanism In Fibroblasts, Ian C. Schneider, Jason M. Haugh Dec 2005

Quantitative Elucidation Of A Distinct Spatial Gradient-Sensing Mechanism In Fibroblasts, Ian C. Schneider, Jason M. Haugh

Ian C. Schneider

Migration of eukaryotic cells toward a chemoattractant often relies on their ability to distinguish receptor-mediated signaling at different subcellular locations, a phenomenon known as spatial sensing. A prominent example that is seen during wound healing is fibroblast migration in platelet-derived growth factor (PDGF) gradients. As in the well-characterized chemotactic cells Dictyostelium discoideum and neutrophils, signaling to the cytoskeleton via the phosphoinositide 3-kinase pathway in fibroblasts is spatially polarized by a PDGF gradient; however, the sensitivity of this process and how it is regulated are unknown. Through a quantitative analysis of mathematical models and live cell total internal reflection fluorescence microscopy …

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A Fast Three-Step Phase-Shifting Algorithm, Peisen S. Huang, Song Zhang Oct 2005

A Fast Three-Step Phase-Shifting Algorithm, Peisen S. Huang, Song Zhang

Song Zhang

We propose a new three-step phase-shifting algorithm, which is much faster than the traditional three-step algorithm. We achieve the speed advantage by using a simple intensity ratio function to replace the arctangent function in the traditional algorithm. The phase error caused by this new algorithm is compensated for by use of a look-up-table (LUT). Our experimental results show that both the new algorithm and the traditional algorithm generate similar results, but the new algorithm is 3.4 times faster. By implementing this new algorithm in a high-resolution, real-time 3D shape measurement system, we were able to achieve a measurement speed of …

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3-D Optical Measurement Using Phase Shifting Based Methods, Peisen S. Huang, Song Zhang Oct 2005

3-D Optical Measurement Using Phase Shifting Based Methods, Peisen S. Huang, Song Zhang

Song Zhang

We review some of our most recent works on 3-D shape measurement using the digital fringe projection and phase-shifting method. First, we introduce the measurement principle and phase-shifting algorithms. Then we discuss an effective method for phase error compensation and a novel idea for system calibration. Finally, we describe a 3-D shape measurement system for high-resolution, real-time 3-D shape acquisition, reconstruction and display.

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Systematic, Multisite Short-Range-Order Corrections To The Electronic Structure Of Disordered Alloys From First Principles: The Kkr Nonlocal Cpa From The Dynamical Cluster Approximation, D. A. Biava, Subhradip Ghosh, Duane D. Johnson, W. A. Shelton, Andrei V. Smirnov Sep 2005

Systematic, Multisite Short-Range-Order Corrections To The Electronic Structure Of Disordered Alloys From First Principles: The Kkr Nonlocal Cpa From The Dynamical Cluster Approximation, D. A. Biava, Subhradip Ghosh, Duane D. Johnson, W. A. Shelton, Andrei V. Smirnov

Duane D. Johnson

Although the Korringa-Kohn-Rostoker coherent-potential approximation (KKR-CPA) is used widely to configurationally average and get electronic structures and energies of disordered alloys, a single-site CPA misses local environment effects, including short-range order (SRO). A proposed nonlocal CPA (NLCPA) recovers translational invariance of the effective medium via k-space coarse graining from the dynamical cluster approximation (DCA), where corrections are systematic as cluster size increases. We implement a first-principles KKR-NLCPA/DCA and show the effects of environment, including SRO, on the electronic structures of fcc CuAu and bcc NiAl.

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Scaling Relations For Dislocation Structure And Response, Richard Alan Lesar, M. Koslowski, Robb Thomson, J. M. Rickman Sep 2005

Scaling Relations For Dislocation Structure And Response, Richard Alan Lesar, M. Koslowski, Robb Thomson, J. M. Rickman

Richard Alan Lesar

A major goal in dislocation theory is the development of a coarse-grained method that would enable predictions of dislocation response without resolving the degrees of freedom of all the dislocations. While a number of possible coarse-grained theories have been proposed, all of these need information about structures at scales smaller than the coarse-graining volume. Here we present results from dislocation simulations that yield scaling relations with the hope that they can provide a framework for modeling the sub-scale dislocation structures and dynamics. For example, we show that dislocations have a self-similar (fractal) structure over wide range of stress/strain; dislocations move …

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Phase Error Compensation For A 3-D Shape Measurement System Based On The Phase-Shifting Method, Song Zhang, Peisen S. Huang Sep 2005

Phase Error Compensation For A 3-D Shape Measurement System Based On The Phase-Shifting Method, Song Zhang, Peisen S. Huang

Song Zhang

This paper describes a novel phase error compensation method for reducing the measurement error caused by non-sinusoidal waveforms in the phase-shifting method. For 3D shape measurement systems using commercial video projectors, the non-sinusoidal nature of the projected fringe patterns as a result of the nonlinear gamma curve of the projectors causes significant phase measurement error and therefore shape measurement error. The proposed phase error compensation method is based on our finding that the phase error due to the non-sinusoidal waveform of the fringe patterns depends only on the nonlinearity of the projector's gamma curve. Therefore, if the projector's gamma curve …

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Signal Processing Strategies That Improve Performance And Understanding Of The Quantitative Ultrasound Spectral Fit Algorithm, Timothy A. Bigelow, William D. O'Brien Sep 2005

Signal Processing Strategies That Improve Performance And Understanding Of The Quantitative Ultrasound Spectral Fit Algorithm, Timothy A. Bigelow, William D. O'Brien

Timothy A. Bigelow

Quantifying the size of the tissue microstructure using the backscattered power spectrum has had limited success due to frequency-dependent attenuation along the propagation path, thus masking the frequency dependence of the scatterer size. Previously, the SPECTRAL FIT algorithm was developed to solve for total attenuation and scatterer size simultaneously [Bigelow et al., J. Acoust. Soc. Am. 117, 1431-1439 (2005)]. Herein, the outcomes from signal processing strategies on the SPECTRAL FIT algorithm are investigated. The signal processing methods can be grouped into two categories, viz., methods that improve the performance of the algorithm and methods that provide insight. The methods that …

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Genetic Programming For Multitimescale Modeling, Kumara Sastry, Duane D. Johnson, David E. Goldberg, Pascal Bellon Aug 2005

Genetic Programming For Multitimescale Modeling, Kumara Sastry, Duane D. Johnson, David E. Goldberg, Pascal Bellon

Duane D. Johnson

A bottleneck for multitimescale thermally activated dynamics is the computation of the potential energy surface. We explore the use of genetic programming (GP) to symbolically regress a mapping of the saddle-point barriers from only a few calculated points via molecular dynamics, thereby avoiding explicit calculation of all barriers. The GP-regressed barrier function enables use of kinetic Monte Carlo to simulate real-time kinetics (seconds to hours) based upon realistic atomic interactions. To illustrate the concept, we apply a GP regression to vacancy-assisted migration on a surface of a concentrated binary alloy (from both quantum and empirical potentials) and predict the diffusion …

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A Model For Estimating Ultrasound Attenuation Along The Propagation Path To The Fetus From Backscattered Waveforms, Timothy A. Bigelow, William D. O'Brien Aug 2005

A Model For Estimating Ultrasound Attenuation Along The Propagation Path To The Fetus From Backscattered Waveforms, Timothy A. Bigelow, William D. O'Brien

Timothy A. Bigelow

Accurate estimates of the ultrasound pressure and/or intensity incident on the developing fetus on a patient-specific basis could improve the diagnostic potential of medical ultrasound by allowing the clinician to increase the transmit power while still avoiding the potential for harmful bioeffects. Neglecting nonlinear effects, the pressure/intensity can be estimated if an accurate estimate of the attenuation along the propagation path (i.e., total attenuation) can be obtained. Herein, a method for determining the total attenuation from the backscattered power spectrum from the developing fetus is proposed. The boundaries between amnion and either the fetus' skull or soft tissue are each …

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The Effect Of A Repetitive, Fatiguing Lifting Task On Horizontal Ground Reaction Forces, Yu Shu, Jonathan Drum, Stephanie Southard, Gwanseob Shin, Gary A. Mirka Aug 2005

The Effect Of A Repetitive, Fatiguing Lifting Task On Horizontal Ground Reaction Forces, Yu Shu, Jonathan Drum, Stephanie Southard, Gwanseob Shin, Gary A. Mirka

Gary A. Mirka

There are many outdoor work environments that involve the combination of repetitive, fatiguing lifting tasks and less-than-optimal footing (muddy/slippery ground surfaces). The focus of the current research was to evaluate the effects of lifting-induced fatigue of the low back extensors on lifting kinematics and ground reaction forces. Ten participants performed a repetitive lifting task over a period of 8 minutes. As they performed this task, the ground reaction forces and whole body kinematics were captured using a force platform and magnetic motion tracking system, respectively. Fatigue was verified in this experiment by documenting a decrease in the median frequency of …

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Synthesis And Characterization Of Highly Amine Functionalized Mesoporous Organosilicas By An “All-In-One” Approach, Rebecca Voss, Arne Thomas, Markus Antonietti, Geoffrey A. Ozin Aug 2005

Synthesis And Characterization Of Highly Amine Functionalized Mesoporous Organosilicas By An “All-In-One” Approach, Rebecca Voss, Arne Thomas, Markus Antonietti, Geoffrey A. Ozin

Rebecca Cademartiri

Mesoporous organosilicas (MOs) represent a promising class of organic–inorganic nanocomposites for a broad range of applications like catalysis, sensing, separation, or microelectronics. Their distinct feature is the presence of organic groups incorporated into the channel walls of a mesoporous structure. Here, we present a convenient “all-in-one” approach using silsesquioxane surfactant precursors for the functionalization of the channel walls with primary amine groups. The monomer is made by a hydroboration/aminolysis sequence on the base of a commercial monomer, with the template bound to the functionalization site by hydroboration and released after silica condensation and aminolysis. This combination ensures both the placement …

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Spatial Analysis Of 3′ Phosphoinositide Signaling In Living Fibroblasts, Iii: Influence Of Cell Morphology And Morphological Polarity, Ian C. Schneider, Elizabeth M. Parrish, Jason M. Haugh Aug 2005

Spatial Analysis Of 3′ Phosphoinositide Signaling In Living Fibroblasts, Iii: Influence Of Cell Morphology And Morphological Polarity, Ian C. Schneider, Elizabeth M. Parrish, Jason M. Haugh

Ian C. Schneider

Activation of phosphoinositide (PI) 3-kinase is a required signaling pathway in fibroblast migration directed by platelet-derived growth factor. The pattern of 3′ PI lipids in the plasma membrane, integrating local Pl 3-kinase activity as well as 3′ PI diffusion and turnover, influences the spatiotemporal regulation of the cytoskeleton. In fibroblasts stimulated uniformly with platelet-derived growth factor, visualized using total internal reflection fluorescence microscopy, we consistently observed localized regions with significantly higher or lower 3′ PI levels than adjacent regions (hot and cold spots, respectively). A typical cell contained multiple hot spots, coinciding with apparent leading edge structures, and at most …

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Crystal-Amorphous And Crystal-Crystal Phase Transformations Via Virtual Melting, Valery I. Levitas Aug 2005

Crystal-Amorphous And Crystal-Crystal Phase Transformations Via Virtual Melting, Valery I. Levitas

Valery I. Levitas

A new mechanism of crystal (c)–amorphous (a) and c-c phase transformations (PTs) and internal stress relaxation via virtual melting (VM) induced by internal stresses was justified thermodynamically and kinetically. VM removes interface friction, reduces kinetic barrier, increases atomic mobility, and can reduce thermodynamic melting temperature. We combine VM and nonequilibrium PT diagrams to develop new scenarios of c-a and c-c PTs. Results are applied for a new interpretation of c-c and c-a PT mechanisms in ice Ih and are also applicable for other materials.

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Elastic Waves Push Organic Fluids From Reservoir Rock, Igor A. Beresnev, R. Dennis Vigil, Wenqing Li, Wayne D. Pennington, Roger M. Turpening, Pavel P. Iassonov, Robert P. Ewing Jul 2005

Elastic Waves Push Organic Fluids From Reservoir Rock, Igor A. Beresnev, R. Dennis Vigil, Wenqing Li, Wayne D. Pennington, Roger M. Turpening, Pavel P. Iassonov, Robert P. Ewing

R. Dennis Vigil

Elastic waves have been observed to increase productivity of oil wells, although the reason for the vibratory mobilization of the residual organic fluids has remained unclear. Residual oil is entrapped as ganglia in pore constrictions because of resisting capillary forces. An external pressure gradient exceeding an ‘‘unplugging’’ threshold is needed to carry the ganglia through. The vibrations help overcome this resistance by adding an oscillatory inertial forcing to the external gradient; when the vibratory forcing acts along the gradient and the threshold is exceeded, instant ‘‘unplugging’’ occurs. The mobilization effect is proportional to the amplitude and inversely proportional to the …

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Inverse Design Of And Experimental Measurements In A Double-Passage Transonic Turbine Cascade Model, G. M. Laskowski, A. Vicharelli, G. Medic, C. J. Elkins, J. K. Eaton, Paul A. Durbin Jul 2005

Inverse Design Of And Experimental Measurements In A Double-Passage Transonic Turbine Cascade Model, G. M. Laskowski, A. Vicharelli, G. Medic, C. J. Elkins, J. K. Eaton, Paul A. Durbin

Paul A. Durbin

A new transonic turbine cascade model that accurately produces infinite cascade flow conditions with minimal compressor requirements is presented. An inverse design procedure using the Favre-averaged Navier-Stokes equations and k-ε turbulence model based on the method of steepest descent was applied to a geometry consisting of a single turbine blade in a passage. For a fixed blade geometry, the passage walls were designed such that the surface isentropic Mach number (SIMN) distribution on the blade in the passage matched the SIMN distribution on the blade in an infinite cascade, while maintaining attached flow along both passage walls. An experimental rig …

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Temperature Dependence Of Order, Disorder, And Defects In Laterally Confined Diblock Copolymer Cylinder Monolayers, Matthew R. Hammond, Eric W. Cochran, Glenn H. Fredrickson, Edward J. Kramer Jul 2005

Temperature Dependence Of Order, Disorder, And Defects In Laterally Confined Diblock Copolymer Cylinder Monolayers, Matthew R. Hammond, Eric W. Cochran, Glenn H. Fredrickson, Edward J. Kramer

Eric W. Cochran

Monolayer arrays of polystyrene-poly(2-vinylpyridine) diblock copolymer cylinders with excellent orientational order and a very low density of dislocations are prepared by cooling slowly from above the bulk order - disorder temperature (ODT) ∼212°C within silicon oxide channels one cylinder spacing a in depth and 2 μm in width. The translational order of this array, however, is short range with a correlation length of ∼12a. If such an array is heated to a temperature above the glass transition temperature of the block copolymer (100°C) but well below the ODT, a finite density of thermally generated dislocations is observed, which leads to …

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Design Considerations For The Construction And Operation Of Malting Facilities. Part I: Planning, Structural, And Life Safety Considerations, Gregory D. Williams, Kurt A. Rosentrater Jul 2005

Design Considerations For The Construction And Operation Of Malting Facilities. Part I: Planning, Structural, And Life Safety Considerations, Gregory D. Williams, Kurt A. Rosentrater

Kurt A. Rosentrater

Malt production facilities are the producers of ingredients for our baking, beverage, and specialty food industries. To date, information about the unique design requirements of these facilities has been limited. In an effort to summarize state of the art design procedures for malting facilities constructed in North America, an overview of accepted standards and procedures has been assembled. With this paper engineers should become more familiar with specific design considerations for malting plants and develop appropriate references to expand their knowledge base. Educators may find this paper useful too.

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Effect Of Moisture Content And Soluble Levels On The Physical And Chemical Properties Of Ddgs, Vykundeshwari Ganesan, Kasiviswanathan Muthukumarappan, Kurt A. Rosentrater Jul 2005

Effect Of Moisture Content And Soluble Levels On The Physical And Chemical Properties Of Ddgs, Vykundeshwari Ganesan, Kasiviswanathan Muthukumarappan, Kurt A. Rosentrater

Kurt A. Rosentrater

Over the past few decades, researches concerning handling and storage characteristics of bulk solids have been conducted to a large extent. Distillers Dried Grains with Solubles (DDGS) are a bulk material that has been widely used as a protein source for ruminants and non-ruminants for more than two decades. Distillers’ grains are energy dense as they contain high fat levels. With the exponential growth of the fuel ethanol industry in the past several years, significant quantities of distiller’s grains are now being produced. To effectively utilize these feeds in the domestic market, however, these coproduct streams are increasingly being transported …

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Utilization Of Distillers Dried Grains For Fish Feed By Extrusion Technology—A Review, Nehru Chevanan, Kurt A. Rosentrater, Kasiviswanathan Muthukumarappan Jul 2005

Utilization Of Distillers Dried Grains For Fish Feed By Extrusion Technology—A Review, Nehru Chevanan, Kurt A. Rosentrater, Kasiviswanathan Muthukumarappan

Kurt A. Rosentrater

Protein-rich distillers dried grains (DDG) from ethanol plants has been used as livestock feed for many years. Feed conversion efficiency in fish, however, is typically much higher compared to traditional livestock. But, the cost of fish feed is one of the challenges for profitable fish cultivation. Due to the exponential growth of ethanol plants in recent years, DDG is becoming readily available as a reasonably-priced base material for animal feeds, and because it has a relatively high protein content, it also has much potential for use as a fish feed ingredient. Even though much literature is available on conversion of …

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Update On Utilizing Ethanol Processing Residues In Food Products, Kurt A. Rosentrater, Padmanaban Krishnan Jul 2005

Update On Utilizing Ethanol Processing Residues In Food Products, Kurt A. Rosentrater, Padmanaban Krishnan

Kurt A. Rosentrater

The production of corn-based ethanol in the U.S. is dramatically increasing, and consequently so is the quantity of byproduct materials generated from this processing sector. These coproduct streams are currently solely utilized as livestock feed, which is a route that provides ethanol processors with a substantial revenue source and significantly increases the profitability of the production process. With the construction and operation of many new plants in recent years, these residuals do, however, have much potential for value-added processing and utilization in the human food sector as well. This option holds promise of economic benefit for corn processors, especially if …

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Update On Ethanol Processing Residue Properties, Kurt A. Rosentrater, Kasiviswanathan Muthukumarappan, James Julson, Padmanaban Krishnan Jul 2005

Update On Ethanol Processing Residue Properties, Kurt A. Rosentrater, Kasiviswanathan Muthukumarappan, James Julson, Padmanaban Krishnan

Kurt A. Rosentrater

The production of corn-based ethanol in the U.S. is dramatically increasing, and consequently so is the amount of byproduct materials generated from this processing sector. These coproduct streams are currently solely utilized as livestock feed, which is a route that provides ethanol processors with a substantial revenue source and significantly increases the profitability of the production process. With the construction and operation of many new plants in recent years, these residuals do, however, have much potential for value-added processing and utilization in other sectors as well. This option holds promise of economic benefit for corn processors, especially if the livestock …

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Physical Properties Of Extruded Tilapia Feed With Distiller Dried Grains With Solubles, Nehru Chevanan, Kurt A. Rosentrater, Kasiviswanathan Muthukumarappan Jul 2005

Physical Properties Of Extruded Tilapia Feed With Distiller Dried Grains With Solubles, Nehru Chevanan, Kurt A. Rosentrater, Kasiviswanathan Muthukumarappan

Kurt A. Rosentrater

Distillers’ dried grains with solubles (DDGS) from ethanol manufacturing plants contain a high percentage of protein, and are primarily used as livestock feed. The conversion efficiency of feed into body tissue is generally much higher in fish than farm animals. Fish can convert up to 36% of feed protein into body protein, whereas beef typically converts only 15%. Extrusion technology is very widely used for the production of floating and non floating aquaculture feeds. Therefore, the objective of this study was to quantify physical properties of extrudates containing 20,30 & 40% DDGS and net protein content adjusted to 28%. Three …

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Ethics For Industrial Technology Majors: Need And Plan Of Action, Kurt A. Rosentrater, R. Balamuralikrishma Jun 2005

Ethics For Industrial Technology Majors: Need And Plan Of Action, Kurt A. Rosentrater, R. Balamuralikrishma

Kurt A. Rosentrater

The recent introduction of sessions dedicated to “Industrial Technology” in the annual ASEE conference is testimony that this discipline has gained its rightful place in the company of engineering and engineering technology. This new level of partnership and collaboration between engineering and technology programs promises to be a step in the right direction for society at large. Engineering and technology majors both supplement and complement each other’s knowledge and skills and it is crucial for educators to build bridges of active interaction. This paper takes aim at one specific as well as basic need in teamwork and interdisciplinary projects – …

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Essential Highlights Of The History Of Fluid Mechanics, Kurt A. Rosentrater, R. Balamuralikrishma Jun 2005

Essential Highlights Of The History Of Fluid Mechanics, Kurt A. Rosentrater, R. Balamuralikrishma

Kurt A. Rosentrater

To achieve accreditation, engineering and technology programs throughout the United States must meet guidelines established by the Accreditation Board for Engineering and Technology (ABET). One of these requirements is that departments demonstrate that they provide students with an understanding of engineering in a broad, societal context. Examination of engineering history can be an essential element to this endeavor, because the development of modern theories and practices have diverse and complex evolutions which are often intimately intertwined with the development of societies themselves. Fluid mechanics is a key field of engineering, whose body of knowledge has had a significant influence on …

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Flowability And Handling Characteristics Of Bulk Solids And Powders—A Review, Vykundeshwari Ganesan, Kasiviswanathan Muthukumarappan, Kurt A. Rosentrater Jun 2005

Flowability And Handling Characteristics Of Bulk Solids And Powders—A Review, Vykundeshwari Ganesan, Kasiviswanathan Muthukumarappan, Kurt A. Rosentrater

Kurt A. Rosentrater

Much research regarding handling and storage characteristics of bulk solids has been conducted over the years. Physical properties of granular solids play a significant role in their resulting flow and storage behavior, and are therefore essential to design appropriate, efficient, and economic bulk solids handling and storage equipment and structures. Distillers Dried Grains with Solubles (DDGS) are a bulk material that has been widely used as a protein source for ruminants and non-ruminants for more than two decades. Distillers' grains are energy dense as they contain high fat levels. With the exponential growth of the fuel ethanol industry in the …

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Evaluation Of Controller Area Network Data Collection System In Confined Animal Feeding Operations, Matthew J. Darr, Lingying Zhao, M. R. Ehsani, J. K. Ward, T. S. Stombaugh May 2005

Evaluation Of Controller Area Network Data Collection System In Confined Animal Feeding Operations, Matthew J. Darr, Lingying Zhao, M. R. Ehsani, J. K. Ward, T. S. Stombaugh

Matthew J. Darr

Livestock and poultry industries play an important role in the food supply and economy of US agriculturalists. Current and historical trends show that the number of animals housed in individual facilities continues to grow on a yearly basis. While design improvements have enabled structures to physically house the growing number of livestock, a new problem exists in maintaining a safe indoor environment due to the increases in animal waste production. The Environmental Protection Agency is also beginning to enforce regulations to limit the daily emission rate of specific gases and odors associated with animal production. Research is needed to identify …

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Ammonia And Hydrogen Sulfide Flux From Beef Cattle Pens: Implications For Air Quality Measurement Methodologies And Evaluation Of Emission Controls, Jacek A. Koziel, David B. Parker, Bok-Haeng Baek, Kevin J. Bush, Marty Rhoades, Zena Perschbacher-Buser May 2005

Ammonia And Hydrogen Sulfide Flux From Beef Cattle Pens: Implications For Air Quality Measurement Methodologies And Evaluation Of Emission Controls, Jacek A. Koziel, David B. Parker, Bok-Haeng Baek, Kevin J. Bush, Marty Rhoades, Zena Perschbacher-Buser

Jacek A. Koziel

Ammonia (NH 3 ) and hydrogen sulfide (H 2 S) are emitted from beef cattle feedlots with NH 3 being greater by nearly three orders of magnitude. Nearly 30% of the U.S. beef cattle are fed in the High Plains of Texas. Earlier research indicates that abatement technologies may be needed to significantly reduce NH 3 emissions. To date, little is known about the appropriate measurement methods to evaluate the effectiveness of NH 3 emission controls. In this research, we determined the (a) variability of NH 3 and H 2 S fluxes within a single pen and (b) the relationships …

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Unsteady Effects On Trailing Edge Cooling, G. Medic, Paul A. Durbin Apr 2005

Unsteady Effects On Trailing Edge Cooling, G. Medic, Paul A. Durbin

Paul A. Durbin

It is shown how natural and forced unsteadiness play a major role in turbine blade trailing edge cooling flows. Reynolds averaged simulations are presented for a surface jet in coflow, resembling the geometry of the pressure side breakout on a turbine blade. Steady computations show very effective cooling; however when natural-or even moreso, forced-unsteadiness is allowed, the adiabatic effectiveness decreases substantially. Streamwise vortices in the mean flow are found to be the cause of the increased heat transfer.

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Optimizing Vibration Isolation Of Flex Circuits In Hard Disk Drives, M. R. Brake, Jonathan A. Wickert Apr 2005

Optimizing Vibration Isolation Of Flex Circuits In Hard Disk Drives, M. R. Brake, Jonathan A. Wickert

Jonathan A. Wickert

A "flex circuit" is a laminate of polyimide substrate, adhesive, and copper conductors that is used to connect the stationary electronic components in a computer hard disk drive to the rotating arm that positions read/write heads above the disks. The flex circuit's transverse and longitudinal vibrations couple with the arm, and those motions, although seemingly small, degrade performance during seek operations from one data track to another. The flex circuit and arm mechanism is defined by a number of geometric parameters, and some latitude is available at the design stage for choosing dimensions and angles so as to minimize vibration …

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Essential Considerations For Manufacturing Products Containing Biological Materials, Kurt A. Rosentrater, Andrew W. Otieno Apr 2005

Essential Considerations For Manufacturing Products Containing Biological Materials, Kurt A. Rosentrater, Andrew W. Otieno

Kurt A. Rosentrater

An engine that drives the United States’ economic growth is an ever-increasing demand for manufactured products, both at home and abroad. As environmental concerns grow, however, renewable resources are gaining increasing attention, especially as industrial ecology and product biodegradability gain in prevalence. Added to this, biological materials are increasingly being utilized to replace traditional materials in manufacturing. To aid both educators as well as researchers, this paper examines several considerations that are essential for manufacturing products that contain biomaterials. These include the selection of materials, the selection of manufacturing processes, manufacturing costs, and the quality of final products. Additionally, several …

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