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Faculty Publications

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Articles 391 - 420 of 914

Full-Text Articles in Chemical Engineering

Characterization Of Macromolecular Structure Elements From A Green River Oil Shale, Ii. Characterization Of Pyrolysis Products By 13c Nmr, Gc/Ms, And Ftir, Thomas H. Fletcher, Ryan Gillis, Jacob Adams, Trent Hall Jan 2014

Characterization Of Macromolecular Structure Elements From A Green River Oil Shale, Ii. Characterization Of Pyrolysis Products By 13c Nmr, Gc/Ms, And Ftir, Thomas H. Fletcher, Ryan Gillis, Jacob Adams, Trent Hall

Faculty Publications

This paper is Part II of a study of the chemical structural components of the organic matter of oil shale in the Green River formation. Three sections of a well-characterized oil shale core from the Utah Green River formation were demineralized, and the resulting kerogen was pyrolyzed at 10 °C/min in nitrogen at atmospheric pressure at temperatures up to 525 °C. The pyrolysis products (light gas, tar, and char) were analyzed using 13C NMR, GC/MS, and (FTIR). Pyrolysis yields of 80% (daf basis) were achieved at these conditions, with 60% daf tar yield at the highest temperature. The solid-state …

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A Post-Installed Subsea Monitoring System For Structural And Flow Assurance Evaluation, David Brower, Alexis Brower, John Hedengren, Reza Asgharzadeh Shishavan Jan 2014

A Post-Installed Subsea Monitoring System For Structural And Flow Assurance Evaluation, David Brower, Alexis Brower, John Hedengren, Reza Asgharzadeh Shishavan

Faculty Publications

This paper describes major advancements for deploying sensing systems on existing subsea structures as part of the Clear Gulf study. In the past, a major shortcoming of post-installed monitoring systems has been poor coupling between the sensor and structure; this study provided methods to overcome this problem. Both subsea field testing and laboratory testing were performed to verify these advancements. The Clear Gulf study is a collaboration between the offshore energy industry and NASA with the goals of risk mitigation, safety, efficiency and environmental concerns in the offshore energy industry. The study is ongoing and has investigated new methods to …

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Optimal Trajectory Generation Using Model Predictive Control For Aerially Towed Cable Systems, Liang Sun, John Hedengren, Randal W. Beard Jan 2014

Optimal Trajectory Generation Using Model Predictive Control For Aerially Towed Cable Systems, Liang Sun, John Hedengren, Randal W. Beard

Faculty Publications

This paper studies trajectory generation for a mothership that tows a drogue using a flexible cable. The contributions of this paper include model validation for the towed cable system described by a lumped mass extensible cable using flight data, and optimal trajectory generation for the towed cable system with tension constraints using model predictive control. The optimization problem is formulated using a combination of the squared error and l1-norm objective functions. Different desired circular trajectories of the towed body are used to calculate optimal trajectories for the towing vehicle subject to performance limits and wind disturbances. Trajectory generation for transitions …

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Co2 Char Gasification Rates Of Sawdust, Switchgrass, And Corn Stover In A Pressurized Entrained-Flow Reactor, Thomas H. Fletcher, Aaron D. Lewis, Emmett G. Fletcher Jan 2014

Co2 Char Gasification Rates Of Sawdust, Switchgrass, And Corn Stover In A Pressurized Entrained-Flow Reactor, Thomas H. Fletcher, Aaron D. Lewis, Emmett G. Fletcher

Faculty Publications

An entrained-flow flat-flame burner reactor was used to measure apparent CO2 gasification rates of near-spherical biomass chars of poplar sawdust, switchgrass, and corn stover using particle residence times1258−1891 K and 6.1− 13.5 atm, respectively. A new method was developed to produce near-spherical particles from nonspherical biomass chars. The apparent CO2 gasification rates for the three biomass chars with mean diameters near 100 μm were fit to a global first-order model, and the optimal kinetic parameters are reported. The measured gasification rate of poplar sawdust was about 3.9 times faster than that of switchgrass char, but only about 20% faster than …

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Co2 Gasification Rates Of Petroleum Coke In A Pressurized Flat-Flame Burner Entrained-Flow Reactor, Aaron D. Lewis, Emmett G. Fletcher, Thomas H. Fletcher Jan 2014

Co2 Gasification Rates Of Petroleum Coke In A Pressurized Flat-Flame Burner Entrained-Flow Reactor, Aaron D. Lewis, Emmett G. Fletcher, Thomas H. Fletcher

Faculty Publications

Two petcoke samples were gasified by CO2 at total pressures of 10 and 15 atm in a high-pressure flat-flame burner reactor at conditions where the bulk phase consisted of either 40 or 90 mol % CO2 with gas temperatures up to 1909 K. Particle diameters of 45−75 μm were used in the experiments. The morphology of the two petroleum coke chars was drastically different and evaluated using scanning electron microscopy images of the chars. The mass release data caused by CO2 gasification of the petcoke chars were fit to a global first-order model, and the optimal kinetic parameters are reported. …

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Application Of L-Systems To Geometrical Construction Of Chamise And Juniper Shrubs, Dallan R. Prince, Marianne E. Fletcher, Chen Shen, Thomas H. Fletcher Jan 2014

Application Of L-Systems To Geometrical Construction Of Chamise And Juniper Shrubs, Dallan R. Prince, Marianne E. Fletcher, Chen Shen, Thomas H. Fletcher

Faculty Publications

Improved models of fire spread and fire characteristics are desired for live shrub fuels, since the majority of existing research efforts focus on either dead fuel beds or crown fires in trees. Efforts have been made to improve live fuel modeling, including detailed studies of individual leaf combustion, with results incorporated into a shrub combustion model for broadleaf species. However, this approach was not well-suited to non-broadleaf shrubs since their fuel consists of long needle-covered branches rather than easily discretized leaves. Methods were therefore developed to simulate the branching structure of chamise (Adenostoma fasciculatum) and Utah juniper (Juniperus osteosperma). The …

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Simulation Of The Swelling Of High-Volatile Bituminous Coal During Pyrolysis, He Yang, Sufen Li, Thomas H. Fletcher, Ming Dong Jan 2014

Simulation Of The Swelling Of High-Volatile Bituminous Coal During Pyrolysis, He Yang, Sufen Li, Thomas H. Fletcher, Ming Dong

Faculty Publications

In this paper, a model is established to predict the swelling ratio of high-volatile bituminous coal during pyrolysis, based on the assumption that the structure of bubble distribution in the particle at the beginning of the plastic stage is a central bubble surrounded by many surrounding bubbles. The initial number and size of the bubbles when the particles become plastic are calculated by the pressure in the particle. The chemical percolation devolatilization (CPD) model is used to describe pyrolysis. The pyrolysis of eight types of high-volatile bituminous coals is simulated, and the results are compared with experimental results to verify …

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Simulation Of The Evolution Of Pressure In A Lignite Particle During Pyrolysis, He Yang, Sufen Li, Thomas H. Fletcher, Ming Dong, Weishi Zhou Jan 2014

Simulation Of The Evolution Of Pressure In A Lignite Particle During Pyrolysis, He Yang, Sufen Li, Thomas H. Fletcher, Ming Dong, Weishi Zhou

Faculty Publications

The evolution of pressure in a lignite particle during pyrolysis was simulated on the basis of the gas motion equation in porous media and considering the Klinkenberg effect. The chemical percolation devolatilization (CPD) model was used to describe pyrolysis. The pore diameter in the particle is close to the average free path of volatile gas molecules; therefore, the solid phase restrains the movement of gas. Because flow out of the particle is restricted, the internal pressure rises. The internal pressure first increases and then decreases during pyrolysis, and the evolution is influenced by heating conditions. The pressure rise is larger …

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Differences In Burning Behavior Of Live And Dead Leaves, Part 1: Measurements, Thomas H. Fletcher, Dallan R. Prince Jan 2014

Differences In Burning Behavior Of Live And Dead Leaves, Part 1: Measurements, Thomas H. Fletcher, Dallan R. Prince

Faculty Publications

Burning behaviors of individual live and dead leaves were measured in a well-instrumented, well-controlled flat-flame burner. Manzanita (Arctostaphylos glandulosa) branches were harvested from the Chaparral near Riverside, California. Leaves were conditioned to several moisture contents. Two “live” (i.e., not fully dried) groups remained above the fiber saturation point at 34% moisture content (MC; dry basis) and 63% MC. Two “dead” groups were dried to about 4% MC, and one was rehydrated back up to 26% MC. Distinct plateaus in surface temperatures at 175◦C were observed while burning live leaves, but dead leaves showed weaker plateaus, if any. Evidence of high …

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Self-Healing Catalysts: Co3O4 Nanorods For Fischer-Tropsch Synthesis, Cun Wen, Darrius D. Dunbar, Xin Zhang, Jochen A. Lauterbach, Jason R. Hattrick-Simpers Jan 2014

Self-Healing Catalysts: Co3O4 Nanorods For Fischer-Tropsch Synthesis, Cun Wen, Darrius D. Dunbar, Xin Zhang, Jochen A. Lauterbach, Jason R. Hattrick-Simpers

Faculty Publications

We combine kinetic and spectroscopic data to demonstrate the concept of a self-healing catalyst, which effectively eliminates the need for catalyst regeneration. The observed self-healing is triggered by controlling the crystallographic orientation at the catalyst surface.

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One-Step Production Of Long-Chain Hydrocarbons From Waste-Biomass-Derived Chemicals Using Bi-Functional Heterogeneous Catalysts, Cun Wen, Elizabeth A. Barrow, Jason R. Hattrick-Simpers, Jochen A. Lauterbach Jan 2014

One-Step Production Of Long-Chain Hydrocarbons From Waste-Biomass-Derived Chemicals Using Bi-Functional Heterogeneous Catalysts, Cun Wen, Elizabeth A. Barrow, Jason R. Hattrick-Simpers, Jochen A. Lauterbach

Faculty Publications

n this study, we demonstrate the production of long-chain hydrocarbons (C8+) from 2-methylfuran (2MF) and butanal in a single step reactive process by utilizing a bi-functional catalyst with both acid and metallic sites. Our approach utilizes a solid acid for the hydroalkylation function and as a support as well as a transition metal as hydrodeoxygenation catalyst. A series of solid acids was screened, among which MCM-41 demonstrated the best combination of activity and stability. Platinum nanoparticles were then incorporated into the MCM-41. The Pt/MCM-41 catalyst showed 96% yield for C8+ hydrocarbons and the catalytic performance was stable …

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Tuning The Underwater Oleophobicity Of Graphene Oxide Coatings Via Uv Irradiation, H. Li, Yi Huang, Y. Mao, W. Xu, Harry J. Ploehn, Miao Yu Jan 2014

Tuning The Underwater Oleophobicity Of Graphene Oxide Coatings Via Uv Irradiation, H. Li, Yi Huang, Y. Mao, W. Xu, Harry J. Ploehn, Miao Yu

Faculty Publications

Ultraviolet (UV) irradiation was utilized to gradually modify the chemistry and structure of graphene oxide (GO) flakes, as confirmed by XPS and AFM. Ultrathin GO coatings/membranes, made of UV-irradiated flakes, showed tunable underwater oleophobicity. UV-treated, superoleophobic GO membranes exhibited excellent antifouling capability for oil/water separation.

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In-Situ Study Of E-Beam Al And Hf Metal Deposition On Native Oxide Inp (100), H. Dong, Santosh Kc, A. Azcatl, W. Cabrera, X. Qin, B. Brennan, D. Zhernokletov, K. Cho, R. Wallace Nov 2013

In-Situ Study Of E-Beam Al And Hf Metal Deposition On Native Oxide Inp (100), H. Dong, Santosh Kc, A. Azcatl, W. Cabrera, X. Qin, B. Brennan, D. Zhernokletov, K. Cho, R. Wallace

Faculty Publications

The interfacial chemistry of thin Al (∼3 nm) and Hf (∼2 nm) metal films deposited by electron beam (e-beam) evaporation on native oxide InP (100) samples at room temperature and after annealing has been studied by in situ angle resolved X-ray photoelectron spectroscopy and low energy ion scattering spectroscopy. The In-oxides are completely scavenged forming In-In/In-(Al/Hf) bonding after Al and Hf metal deposition. The P-oxide concentration is significantly decreased, and the P-oxide chemical states have been changed to more P-rich oxides upon metal deposition. Indium diffusion through these metals before and after annealing at 250 °C has also been characterized. …

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Modeling The Relaxation Time Of Dna Confined In A Nanochannel, Douglas R. Tree, Yanwei Wang, Kevin D. Dorfman Oct 2013

Modeling The Relaxation Time Of Dna Confined In A Nanochannel, Douglas R. Tree, Yanwei Wang, Kevin D. Dorfman

Faculty Publications

Using a mapping between a Rouse dumbbell model and fine-grained Monte Carlo simulations, we have computed the relaxation time of λ-DNA in a high ionic strength buffer confined in a nanochannel. The relaxation time thus obtained agrees quantitatively with experimental data [Reisner et al., Phys. Rev. Lett. 94, 196101 (2005)] using only a single O(1) fitting parameter to account for the uncertainty in model parameters. In addition to validating our mapping, this agreement supports our previous estimates of the friction coefficient of DNA confined in a nanochannel [Tree et al., Phys. Rev. Lett. 108, 228105 …

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In Situ Study Of The Role Of Substrate Temperature During Atomic Layer Deposition Of Hfo2 On Inp, H. Dong, Santosh Kc, X. Qin, B. Brennan, S. Mcdonnell, D. Zhernokletov, C. Hinkle, J. Kim, K. Cho, R. Wallace Oct 2013

In Situ Study Of The Role Of Substrate Temperature During Atomic Layer Deposition Of Hfo2 On Inp, H. Dong, Santosh Kc, X. Qin, B. Brennan, S. Mcdonnell, D. Zhernokletov, C. Hinkle, J. Kim, K. Cho, R. Wallace

Faculty Publications

The dependence of the “self cleaning” effect of the substrate oxides on substrate temperature during atomic layer deposition (ALD) of HfO2 on various chemically treated and native oxide InP (100) substrates is investigated using in situ X-ray photoelectron spectroscopy. The removal of In-oxide is found to be more efficient at higher ALD temperatures. The P oxidation states on native oxide and acid etched samples are seen to change, with the total P-oxide concentration remaining constant, after 10 cycles of ALD HfO2 at different temperatures. An (NH4)2 S treatment is seen to effectively remove native oxides and passivate the InP surfaces …

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Is Dna A Good Model Polymer?, Douglas R. Tree, Abhiram Muralidhar, Patrick S. Doyle, Kevin D. Dorfman Oct 2013

Is Dna A Good Model Polymer?, Douglas R. Tree, Abhiram Muralidhar, Patrick S. Doyle, Kevin D. Dorfman

Faculty Publications

The details surrounding the crossover from wormlike-specific to universal polymeric behavior has been the subject of debate and confusion even for the simple case of a dilute, unconfined wormlike chain. We have directly computed the polymer size, form factor, free energy, and Kirkwood diffusivity for unconfined wormlike chains as a function of molecular weight, focusing on persistence lengths and effective widths that represent single-stranded and double-stranded DNA in a high ionic strength buffer. To do so, we use a chain-growth Monte Carlo algorithm, the pruned-enriched Rosenbluth method (PERM), which allows us to estimate equilibrium and near-equilibrium dynamic properties of wormlike …

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Cell-Free Unnatural Amino Acid Incorporation With Alternative Energy Systems And Linear Expression Templates, Prashanta Shrestha, Mark Thomas Smith, Bradley Charles Bundy Oct 2013

Cell-Free Unnatural Amino Acid Incorporation With Alternative Energy Systems And Linear Expression Templates, Prashanta Shrestha, Mark Thomas Smith, Bradley Charles Bundy

Faculty Publications

Site-specific incorporation of unnatural amino acids (uAAs) during protein synthesis expands the proteomic code through the addition of unique residue chemistry. This field provides a unique tool to improve pharmacokinetics, cancer treatments, vaccine development, proteomics and protein engineering. The limited ability to predict the characteristics of proteins with uAA-incorporation creates a need for a low-cost system with the potential for rapid screening. Escherichia coli-based cell-free protein synthesis is a compelling platform for uAA incorporation due to the open and accessible nature of the reaction environment. However, typical cell-free systems can be expensive due to the high cost of energizing …

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A Course Grain Model For Protein-Surface Interactions, Shuai Wei, Thomas A. Knotts Iv Sep 2013

A Course Grain Model For Protein-Surface Interactions, Shuai Wei, Thomas A. Knotts Iv

Faculty Publications

The interaction of proteins with surfaces is important in numerous applications in many fields—such as biotechnology, proteomics, sensors, and medicine—but fundamental understanding of how protein stability and structure are affected by surfaces remains incomplete. Over the last several years, molecular simulation using coarse grain models has yielded significant insights, but the formalisms used to represent the surface interactions have been rudimentary. We present a new model for protein surface interactions that incorporates the chemical specificity of both the surface and the residues comprising the protein in the context of a one-bead-per-residue, coarse grain approach that maintains computational efficiency. The model …

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A Multi-Physics Model For Solid Oxide Iron-Air Redox Flow Battery: Simulation Of Discharge Behavior At High Current Density, Meng Guo, Xuan Zhao, Ralph E. White, Kevin Huang Aug 2013

A Multi-Physics Model For Solid Oxide Iron-Air Redox Flow Battery: Simulation Of Discharge Behavior At High Current Density, Meng Guo, Xuan Zhao, Ralph E. White, Kevin Huang

Faculty Publications

A rigorous physics-based mathematical model for a solid oxide iron-air redox flow battery system is presented in this paper. The modeled flow battery system combines a Fe-FeO redox couple as the energy storage unit and a regenerative solid oxide fuel cell as the electrical functioning unit in a 2D axial symmetric geometry. This model was developed from fundamental theories of reaction engineering in which basic transport phenomena and chemical/electrochemical kinetics are included. The model shows good agreement with the experimental data. Simulation results for the chemical, electrochemical and transport behavior of the battery are discussed.

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Indium Diffusion Through High-K Dielectrics In High-K/Inp Stacks, H. Dong, W. Cabrera, R. Galatage, Santosh Kc, B. Brennan, X. Qin, S. Mcdonnell, D. Zhernokletov, C. Hinkle, K. Cho, Y. Chabal, R. Wallace Aug 2013

Indium Diffusion Through High-K Dielectrics In High-K/Inp Stacks, H. Dong, W. Cabrera, R. Galatage, Santosh Kc, B. Brennan, X. Qin, S. Mcdonnell, D. Zhernokletov, C. Hinkle, K. Cho, Y. Chabal, R. Wallace

Faculty Publications

Evidence of indium diffusion through high-k dielectric (Al2O3 and HfO2) films grown on InP (100) by atomic layer deposition is observed by angle resolved X-ray photoelectron spectroscopy and low energy ion scattering spectroscopy. The analysis establishes that In-out diffusion occurs and results in the formation of a POx rich interface.High mobility III-V channel materials are contenders to replace Si in semiconductor devices like metal oxide semiconductor filed effect transistors (MOSFETs) for the sub 22 nm technology node.1 Extensive research is being carried out to determine the validity of these III-V materials for use as the channel, in a variety of …

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Model Predictive Control With A Rigorous Model Of A Solid Oxide Fuel Cell, Lee T. Jacobsen, John Hedengren Jul 2013

Model Predictive Control With A Rigorous Model Of A Solid Oxide Fuel Cell, Lee T. Jacobsen, John Hedengren

Faculty Publications

Degradation of Solid Oxide Fuel Cells (SOFCs) can be minimized by maintaining reliability parameters during load changes. These reliability parameters are critical to maintain power generation efficiency over an extended life of the SOFC. For SOFCs to be commercially viable, the life must exceed 20,000 hours for load following applications. This is not yet achieved because transient stresses damage the fuel cell and degrade the performance over time. This study relates the development of a dynamic model for SOFC systems in order to predict optimal manipulated variable moves along a prediction horizon. The model consists of hundreds of states and …

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Dynamic Optimization Of A Solar Thermal Energy Storage System Over A 24 Hour Period Using Weather Forecasts, Kody Powell, John Hedengren, Thomas F. Edgar Jul 2013

Dynamic Optimization Of A Solar Thermal Energy Storage System Over A 24 Hour Period Using Weather Forecasts, Kody Powell, John Hedengren, Thomas F. Edgar

Faculty Publications

A solar thermal power plant is used as a case study for dynamic heat integration with thermal energy storage. Findings show that thermal energy storage gives the system the ability to make the power dispatchable. Additionally, by solving a 24-hour dynamic optimization problem where the plant temperatures and power output are variable allows the system to capture and harvest a higher percentage of solar energy, with the most benefit occurring on mostly cloudy days. The solar energy captured increases 64% from 4.75 MWh to 7.80 MWh using this scheme. Hybrid plant operation and the ability to bypass the storage tanks …

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Advanced Deepwater Monitoring System, David Brower, John Hedengren, Reza Asgharzadeh Shishavan, Alexis Brower Jun 2013

Advanced Deepwater Monitoring System, David Brower, John Hedengren, Reza Asgharzadeh Shishavan, Alexis Brower

Faculty Publications

This study investigates new methods to improve deepwater monitoring and addresses installation of advanced sensors on ”already deployed” risers, flowlines, trees, and other deepwater devices. A major shortcoming of post installed monitoring systems in subsea is poor coupling between the sensor and structure. This study provided methods to overcome this problem. Both field testing in subsea environments and laboratory testing were performed. Test articles included actual flowline pipe and steel catenary risers up to twenty-four inches in diameter. A monitoring device resulting from this study can be installed in-situ on underwater structures and could enhance productivity and improve safety of …

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Extension Of Dna In A Nanochannel As A Rod-To-Coil Transition, Douglas R. Tree, Yanwei Wang, Kevin D. Dorfman May 2013

Extension Of Dna In A Nanochannel As A Rod-To-Coil Transition, Douglas R. Tree, Yanwei Wang, Kevin D. Dorfman

Faculty Publications

DNA confinement in nanochannels is emerging as an important tool for genomics and an excellent platform for testing the theories of confined wormlike polymers. Using cutting-edge, large scale Monte Carlo simulations of asymptotically long wormlike chains, we show that, in analogy to the rod-to-coil transition for free wormlike polymers, there exists a universal, Gauss–de Gennes regime that connects the classic Odijk and de Gennes regimes of channel-confined chains. For DNA in a nanochannel, this Gauss–de Gennes regime spans practically the entire experimentally relevant range of channel sizes, including the nanochannels used in an incipient genome mapping technology.

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A Polarizable Reactive Force Field For Water To Enable Molecular Dynamics Simulations Of Proton Transport, Abhishek Asthana, Dean R. Wheeler May 2013

A Polarizable Reactive Force Field For Water To Enable Molecular Dynamics Simulations Of Proton Transport, Abhishek Asthana, Dean R. Wheeler

Faculty Publications

A new polarizable water model is developed for molecular dynamics (MD) simulations of the proton transport process. The interatomic potential model has three important submodels corresponding to electrostatic interactions, making and breaking of covalent bonds, and treatment of electron exchange and correlation through a van der Waals potential. A polarizable diffuse charge density function was used to describe Coulombic interactions between atoms. Most of the model parameters were obtained from ab initio data for a lone water molecule. Molecules respond realistically to their electrochemical environment by the use of coupled fluctuating charge and fluctuating dipole dynamics, which controlled the charge …

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Revisiting Blob Theory For Dna Diffusivity In Slitlike Confinement, Liang Dai, Douglas R. Tree, Johan R. C. Van Der Maarel, Kevin D. Dorfman, Patrick S. Doyle Apr 2013

Revisiting Blob Theory For Dna Diffusivity In Slitlike Confinement, Liang Dai, Douglas R. Tree, Johan R. C. Van Der Maarel, Kevin D. Dorfman, Patrick S. Doyle

Faculty Publications

Blob theory has been widely applied to describe polymer conformations and dynamics in nanoconfinement. In slit confinement, blob theory predicts a scaling exponent of 2/3 for polymer diffusivity as a function of slit height, yet a large body of experimental studies using DNA produce a scaling exponent significantly less than 2/3. In this work, we develop a theory that predicts that this discrepancy occurs because the segment correlation function for a semiflexible chain such as DNA does not follow the Flory exponent for length scales smaller than the persistence length. We show that these short length scale effects contribute significantly …

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Transforming Synthetic Biology With Cell-Free Systems, Arnaz Ranji, Jeffrey C. Wu, Bradley Charles Bundy, Michael C. Jewett Mar 2013

Transforming Synthetic Biology With Cell-Free Systems, Arnaz Ranji, Jeffrey C. Wu, Bradley Charles Bundy, Michael C. Jewett

Faculty Publications

Cell-free synthetic biology offers an unprecedented level of control and freedom of design for understanding, harnessing, and expanding the capabilities of natural biological systems. Inspired by advances in synthetic biology projects in vivo, recent years have witnessed the emergence of cell-free systems not only as a testing ground for our ability to engineer and analyze biology, but also as technologies capable of efficient and scalable synthesis of complex biological products. Dominant efforts in the field include: programmable nucleic acid circuits; nanomachines; cell-free protein synthesis; cell-free metabolic engineering; and minimal cells. The goals are understanding why nature’s designs work the way …

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Effect Of Cd44 Binding Peptide Conjugated To An Engineered Inert Matrix On Maintenance Of Breast Cancer Stem Cells And Tumorsphere Formation, Xiaoming Yang, Samaneh Kamali Sarvestani, Seyedsina Moeinzadeh, Xuezhong He, Esmaiel Jabbari Mar 2013

Effect Of Cd44 Binding Peptide Conjugated To An Engineered Inert Matrix On Maintenance Of Breast Cancer Stem Cells And Tumorsphere Formation, Xiaoming Yang, Samaneh Kamali Sarvestani, Seyedsina Moeinzadeh, Xuezhong He, Esmaiel Jabbari

Faculty Publications

Introduction: As cancer cells are affected by many factors in their microenvironment, a major challenge is to isolate the effect of a specific factor on cancer stem cells (CSCs) while keeping other factors unchanged. We have developed a synthetic inert 3D polyethylene glycol diacrylate (PEGDA) gel culture system as a unique tool to study the effect of microenvironmental factors on CSCs response. We have reported that CSCs formed in the inert PEGDA gel by encapsulation of breast cancer cells maintain their stemness within a certain range of gel stiffness. The objective was to investigate the effect of CD44 binding peptide …

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A Steady-State Detection (Ssd) Algorithm To Detect Non-Stationary Drifts In Processes, Jeff Kelly, John Hedengren Mar 2013

A Steady-State Detection (Ssd) Algorithm To Detect Non-Stationary Drifts In Processes, Jeff Kelly, John Hedengren

Faculty Publications

Detecting windows or intervals of when a continuous process is operating in a state of steadiness is useful especially when steady-state models are being used to optimize the process or plant on-line or in real-time. The term steady-state implies that the process is operating around some stable point or within some stationary region where it must be assumed that the accumulation or rate-of-change of material, energy and momentum is statistically insignificant or negligible. This new approach is to assume the null-hypothesis that the process is stationary about its mean subject to independent and identically distributed random error or shocks (white-noise) …

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Entropic Depletion Of Dna In Triangular Nanochannels, Wesley F. Reinhart, Douglas R. Tree, Kevin D. Dorfman Mar 2013

Entropic Depletion Of Dna In Triangular Nanochannels, Wesley F. Reinhart, Douglas R. Tree, Kevin D. Dorfman

Faculty Publications

Using Monte Carlo simulations of a touching-bead model of double-stranded DNA, we show that DNA extension is enhanced in isosceles triangular nanochannels (relative to a circular nanochannel of the same effective size) due to entropic depletion in the channel corners. The extent of the enhanced extension depends non-monotonically on both the accessible area of the nanochannel and the apex angle of the triangle. We also develop a metric to quantify the extent of entropic depletion, thereby collapsing the extension data for circular, square, and various triangular nanochannels onto a single master curve for channel sizes in the transition between the …

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