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Articles 5431 - 5460 of 14174

Full-Text Articles in Engineering

Steady-State Method To Measure The In-Plane Thermal Conductivity Of Thin Sheet Materials, Evgeny Pakhomenko, Andrew James Wildridge, Abraham Mathew Koshy, Souvik Das, Andreas Jung Aug 2018

Steady-State Method To Measure The In-Plane Thermal Conductivity Of Thin Sheet Materials, Evgeny Pakhomenko, Andrew James Wildridge, Abraham Mathew Koshy, Souvik Das, Andreas Jung

The Summer Undergraduate Research Fellowship (SURF) Symposium

A new generation of silicon pixel detectors is required to cope with the unprecedented luminosities at the high-luminosity phase of the Large Hadron Collider (HL-LHC) in 2025. The HL-LHC provides a high radiation, high interaction rate environment for the innermost detector region of the CMS detector. This can lead to an uncontrolled increase in temperature of the detector that can destroy the silicon pixels. Moreover, too high operating temperature can add noise to the data obtained from the detector and can slow the read out cheap down. Therefore, the Phase II upgrade to the Compact Muon Solenoid (CMS) experiment requires …


Scaling Relationships Across Chemically Related Adsorbates For Fast Screening Of Alloy Catalysts For Propane Dehydrogenation, Anne Esther Serban, Ranga Rohit Seemakurthi, Brandon C. Bukowski, Jeffrey Greeley Aug 2018

Scaling Relationships Across Chemically Related Adsorbates For Fast Screening Of Alloy Catalysts For Propane Dehydrogenation, Anne Esther Serban, Ranga Rohit Seemakurthi, Brandon C. Bukowski, Jeffrey Greeley

The Summer Undergraduate Research Fellowship (SURF) Symposium

A catalyst is a material which speeds up the rate of a specific reaction. A reaction that is of significant importance to the chemical industry is the selective transformations of light alkanes (ethane, propane), which are largely available in shale gas, to olefins. These olefins can then be converted into higher-value chemicals, materials, and fuels. However, there are several undesired reactions that take place alongside the main dehydrogenation reaction, so a catalyst of high selectivity is desired. Apart from the industrially used PtSn catalyst, work by our experimental collaborators has shown that various other Pt and Pd alloys (In, Zn) …


Bringing Particle Scale Properties Into Descriptions Of Powder Behavior Through The Enhanced Centrifuge Method, Andrew R. Roginski, Caralyn A. Coultas-Mckenney, Contessa G. Norris, Stephen P. Beaudoin Aug 2018

Bringing Particle Scale Properties Into Descriptions Of Powder Behavior Through The Enhanced Centrifuge Method, Andrew R. Roginski, Caralyn A. Coultas-Mckenney, Contessa G. Norris, Stephen P. Beaudoin

The Summer Undergraduate Research Fellowship (SURF) Symposium

Inconsistent powder behavior introduces problems such as agglomeration, poor flowability, dust hazards, and segregation that decrease efficiency in powder processing environments. Understanding how a powder interacts with a surface at the particle scale provides insight into how to accommodate individual particle properties and avoid process deficiencies. This project uses an enhanced centrifuge technique to evaluate the adhesion between a stainless-steel surface and a powder comprised of fluorescent particles. Particles are deposited onto stainless steel plates which are rotated in a centrifuge. The adhesion properties are monitored by tracking the rotational speed at which particles of a known size are removed …


Satellite-Based Monitoring Of Spatiotemporal Changes In Batudulang Forest In Sumbawa, Indonesia, Mohammad Muslim, Arief Budhi Witarto, Wahyu Indrajaya Aug 2018

Satellite-Based Monitoring Of Spatiotemporal Changes In Batudulang Forest In Sumbawa, Indonesia, Mohammad Muslim, Arief Budhi Witarto, Wahyu Indrajaya

Makara Journal of Technology

Space-based earth observation technology applicable to forest inventory and monitoring is well known in the scientific community. High-resolution satellite images form an important data source for forest mapping and change detection at regional and national scales. The value of forest change information derived from remote sensing data is significantly enhanced if this information is integrated into a spatially explicit geographic information system. Satellite-based rapid assessment was conducted to measure spatiotemporal changes in Batudulang forest over the years. The general approach to quantify change in the spatial aspect of the forest involved change detection using moderate-resolution imaging spectro-radiometer satellite-based normalized difference …


Strength Structure Analysis Of Main Gate Graving Dock Using Pontoons For Condition Repairs, Budianto Budianto Aug 2018

Strength Structure Analysis Of Main Gate Graving Dock Using Pontoons For Condition Repairs, Budianto Budianto

Makara Journal of Technology

Main gate graving dock with pontoon type can certainly suffered some level of damage after a long period of operation. Many employments within the graving dock can delay the process repair of main gate. The main gate may not be opened, because employees are still working to ship fabrication process under sea waterline. For accommodate these interrelated conditions, the best solution with repair one side of the main gate with type pontoon and employees can still work ship fabrication process in graving dock conducted simultaneously. The repair process conditions must be required main gate structure that consists of only one …


Microstructures And Hardness Of Tig Welded Experimental 57fe15cr25ni Steel, Parikin Parikin, Mohammad Dani, Abu Khalid Rivai, Agus Hadi Ismoyo, Riza Iskandar, Arbi Dimyati Aug 2018

Microstructures And Hardness Of Tig Welded Experimental 57fe15cr25ni Steel, Parikin Parikin, Mohammad Dani, Abu Khalid Rivai, Agus Hadi Ismoyo, Riza Iskandar, Arbi Dimyati

Makara Journal of Technology

The microstructures and hardness of tungsten inert gas (TIG) welded experimental 57Fe15Cr25Ni steel were investigated through optical–scanning electron microscopy analyses and with a hardness tester, respectively. The welding process restructured the constituent atoms into regular and irregular crystal lattices. Rapid cooling of the weld metal allowed the formation of a dendritic (columnar) structure, with porous grains. By contrast, slow cooling influenced HAZ and led to the formation of grain structures. The crystal lattice became more organized and larger than other zones. Meanwhile, the base metal formed circular nets that covered large area inside thick and thin grain boundaries. The diffraction …


Mapping Of Bruise Of Oil Palm Fresh Fruit Bunch During Loading And Transportation From Field To Mill, Andreas Wahyu Krisdiarto Aug 2018

Mapping Of Bruise Of Oil Palm Fresh Fruit Bunch During Loading And Transportation From Field To Mill, Andreas Wahyu Krisdiarto

Makara Journal of Technology

Fresh fruit bunches (FFBs) are used as raw materials for palm oil, and their transport from a field is a critical step to maintain their quality. Fruit integrity should be maintained so the mill can efficiently obtain palm oil with less than 5% free fatty acid content. Physical treatments for FFBs during loading to truck bins and transport may cause physical injuries. This research aimed to map fruit bruises. The map can be used as a basis in managing transport of FFBs. Physical injuries were assessed by bruise index (BI), which was calculated by measuring the bruise area and weight …


Benchmarking Product Service System Of Generator Set Distributors, Venny Violetta Tiurindah, Tanika Dewi Sofianti Aug 2018

Benchmarking Product Service System Of Generator Set Distributors, Venny Violetta Tiurindah, Tanika Dewi Sofianti

Makara Journal of Technology

Power generation is an industry that is essential to sustain daily life and competes with generator set distributors. The product service system of distributors must be improved to survive the competition. This research aims to develop tools for benchmarking the product service system of generator set distributors. Benchmarking identifies gaps between a product and other competitors’ products. In this work, a product service system board is used to visualize the current product service system of a generator set distributor. A PPIAF framework and a SERVQUAL framework are adapted to assess product performance and service quality, respectively. AHP is used as …


Economic Model Predictive Control Design Via Nonlinear Model Identification, Laura Giuliani, Helen Durand Aug 2018

Economic Model Predictive Control Design Via Nonlinear Model Identification, Laura Giuliani, Helen Durand

Chemical Engineering and Materials Science Faculty Research Publications

Increasing pushes toward next-generation/smart manufacturing motivate the development of economic model predictive control (EMPC) designs which can be practically deployed. For EMPC, the constraints, objective function, and accuracy of the state predictions would benefit from process models that describe the process physics. However, obtaining first- principles models of chemical process systems can be time-consuming or challenging such that it is preferable to develop physics-based process models automatically from process operating data. In this work, we take initial steps in this direction by suggesting that because experiments that are used to characterize first-principles models often target specific types of data, an …


Imaging Characterization Of Current Generating Lipid-Protein Membranes, Joel D. Kamwa Aug 2018

Imaging Characterization Of Current Generating Lipid-Protein Membranes, Joel D. Kamwa

Microelectronics-Photonics Student Works

Imaging Characterization of Current Generating Lipid-protein Membranes


Insights Into Low Salinity Water Flooding, Hasan N. Al-Saedi, Ralph E. Flori, Patrick V. Brady Aug 2018

Insights Into Low Salinity Water Flooding, Hasan N. Al-Saedi, Ralph E. Flori, Patrick V. Brady

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

In our previous work, we examined the potential of divalent cations (Mg2+ and Ca2+) in formation water (FW) for low-salinity (LS) EOR effect, where the increase in divalent cations in FW lowered the impact of LS water EOR.

In this paper, we demonstrate the importance of the same divalent cations in the injected water (both FW and LS water). We also try to relate the percentage of the divalent cations in the injected water to that in the FW to engineer the optimum concentration of the injected water and obtain the maximum oil recovery from sandstone reservoirs. …


A Reference High-Pressure Co2 Adsorption Isotherm For Ammonium Zsm-5 Zeolite: Results Of An Interlaboratory Study, H. G.T. Nguyen, L. Espinal, R. D. Van Zee, M. Thommes, B. Toman, M. S.L. Hudson, E. Mangano, S. Brandani, D. P. Broom, M. J. Benham, K. Cychosz, P. Bertier, F. Yang, B. M. Krooss, R. L. Siegelman, M. Hakuman, K. Nakai, A. D. Ebner, L. Erden, J. A. Ritter, A. Moran, Orhan Talu, Y. Huang, K. S. Walton, P. Billemont, G. De Weireld Aug 2018

A Reference High-Pressure Co2 Adsorption Isotherm For Ammonium Zsm-5 Zeolite: Results Of An Interlaboratory Study, H. G.T. Nguyen, L. Espinal, R. D. Van Zee, M. Thommes, B. Toman, M. S.L. Hudson, E. Mangano, S. Brandani, D. P. Broom, M. J. Benham, K. Cychosz, P. Bertier, F. Yang, B. M. Krooss, R. L. Siegelman, M. Hakuman, K. Nakai, A. D. Ebner, L. Erden, J. A. Ritter, A. Moran, Orhan Talu, Y. Huang, K. S. Walton, P. Billemont, G. De Weireld

Chemical & Biomedical Engineering Faculty Publications

© 2018, The Author(s). This paper reports the results of an international interlaboratory study led by the National Institute of Standards and Technology (NIST) on the measurement of high-pressure surface excess carbon dioxide adsorption isotherms on NIST Reference Material RM 8852 (ammonium ZSM-5 zeolite), at 293.15 K (20 °C) from 1 kPa up to 4.5 MPa. Eleven laboratories participated in this exercise and, for the first time, high-pressure adsorption reference data are reported using a reference material. An empirical reference equation nex=d(1+exp[(-ln(P)+a)/b])c, [nex-surface excess uptake (mmol/g), P-equilibrium pressure (MPa), a = −6.22, b = 1.97, c = 4.73, and d …


State Measurement Spoofing Prevention Through Model Predictive Control Design, Helen Durand Aug 2018

State Measurement Spoofing Prevention Through Model Predictive Control Design, Helen Durand

Chemical Engineering and Materials Science Faculty Research Publications

Security of chemical process control systems against cyberattacks is critical due to the potential for injuries and loss of life when chemical process systems fail. A potential means by which process control systems may be attacked is through the manipulation of the measurements received by the controller. One approach for addressing this is to design controllers that make manipulating the measurements received by the controller in any meaningful fashion very difficult, making the controllers a less attractive target for a cyberattack of this type. In this work, we develop a model predictive control (MPC) implementation strategy that incorporates Lyapunov-based stability …


Opto-Thermal Characterization Of Plasmon And Coupled Lattice Resonances In 2-D Metamaterial Arrays, Vinith Bejugam Aug 2018

Opto-Thermal Characterization Of Plasmon And Coupled Lattice Resonances In 2-D Metamaterial Arrays, Vinith Bejugam

Graduate Theses and Dissertations

Growing population and climate change inevitably requires longstanding dependency on sustainable sources of energy that are conducive to ecological balance, economies of scale and reduction of waste heat. Plasmonic-photonic systems are at the forefront of offering a promising path towards efficient light harvesting for enhanced optoelectronics, sensing, and chemical separations. Two-dimensional (2-D) metamaterial arrays of plasmonic nanoparticles arranged in polymer lattices developed herein support thermoplasmonic heating at off-resonances (near infrared, NIR) in addition to regular plasmonic resonances (visible), which extends their applicability compared to random dispersions. Especially, thermal responses of 2-D arrays at coupled lattice resonance (CLR) wavelengths were comparable …


Screen Printed Moisture Sensor On Barrier Coated Sbs Board: The Characterizations Of The Hemicellulose-Based Biofilms And Their Applications For Smart Packaging, Ruoxi Ma Aug 2018

Screen Printed Moisture Sensor On Barrier Coated Sbs Board: The Characterizations Of The Hemicellulose-Based Biofilms And Their Applications For Smart Packaging, Ruoxi Ma

Dissertations

Fiber-based packaging materials have many advantages over their petroleum-based plastic competitors, such as sustainability, recyclability and stiffness/weight ratio. However, the poor barrier properties and sensitivity towards moisture are the main challenges for their extended use. Therefore, there has been a need to provide a biodegradable and biocompatible biopolymer packaging material with improved barrier properties for food and pharmaceutical packaging. Also, the moisture loss/gain problem causes a lot of waste every year. Therefore, there is a need of better tracking and sensing methods attached to the package in order to control the moisture level along the supply chain. To accomplish these …


First Principles-Based Microkinetic Modeling Of Ethanol From Syngas On Bimetallic Co-Pd Catalysts, Anuradha Gundamaraju Aug 2018

First Principles-Based Microkinetic Modeling Of Ethanol From Syngas On Bimetallic Co-Pd Catalysts, Anuradha Gundamaraju

All Dissertations

In the future, the availability of reliable alternative fuels will be crucial for any country to become energy independent. One such alternative is ethanol as it can be used both as a fuel and as a fuel additive. Most of the ethanol produced in the world today is derived from biomass. The biomass feedstocks and fermentation broths used in ethanol production both contain high amounts of water and therefore, the energy efficiency of the process is lessened by product separation processes (azeotropic separation of water and ethanol) that are non-trivial and highly inefficient (due to the evaporation of water). An …


Pyrolysis Of Plastic Waste From Medical Services Facilities Into Potential Fuel And/Or Fuel Additives, Bright Kweku Ansah Baiden Aug 2018

Pyrolysis Of Plastic Waste From Medical Services Facilities Into Potential Fuel And/Or Fuel Additives, Bright Kweku Ansah Baiden

Masters Theses

Limited space and high costs for landfilling as well as increasing regulations in plastic waste disposal, has led to high operating costs for organizations involved in managing plastic waste from medical facilities which led to the need to investigate an alternative option such as pyrolysis. The overall goal of this study was to evaluate pyrolysis as a means to repurpose plastic waste obtained from medical service facilities into fuel and fuel additive compounds, with two objectives involving, (1) to examine the effect of heat input (as voltage) and reaction/residence time; and (2) to evaluate the effect of the plastic waste …


Uncoupling Fermentative Synthesis Of Molecular Hydrogen From Biomass Formation In Thermotoga Maritima, Raghuveer Singh, Derrick White, Yaşar Demirel, Robert Kelley, Kenneth Noll, Paul H. Blum Aug 2018

Uncoupling Fermentative Synthesis Of Molecular Hydrogen From Biomass Formation In Thermotoga Maritima, Raghuveer Singh, Derrick White, Yaşar Demirel, Robert Kelley, Kenneth Noll, Paul H. Blum

Department of Chemical and Biomolecular Engineering: Faculty Publications

When carbohydrates are fermented by the hyperthermophilic anaerobe Thermotoga maritima, molecular hydrogen (H2) is formed in strict proportion to substrate availability. Excretion of the organic acids acetate and lactate provide an additional sink for removal of excess reductant. However, mechanisms controlling energy management of these metabolic pathways are largely unexplored. To investigate this topic, transient gene inactivation was used to block lactate production as a strategy to produce spontaneous mutant cell lines that overproduced H2 through mutation of unpredicted genetic targets. Single-crossover homologous chromosomal recombination was used to disrupt lactate dehydrogenase (encoded by ldh) with …


Effect Of Differences In The Primary Structure Of The A-Chain On The Aggregation Of Insulin Fragments, Paul P. Nakka, Ke Li, Daniel Forciniti Aug 2018

Effect Of Differences In The Primary Structure Of The A-Chain On The Aggregation Of Insulin Fragments, Paul P. Nakka, Ke Li, Daniel Forciniti

Chemical and Biochemical Engineering Faculty Research & Creative Works

Bovine and human insulin have similar primary structures. In this article, the region of the insulin A-chain of bovine and human insulin where the amino acid composition is different was studied. Bovine insulin fragment (BIF) and human insulin fragment (HIF) were synthesized in solid-phase peptide synthesis. The effects of pH, temperature, urea, ionic strength, and stirring on the formation of fibrils were studied using a fractional factorial resolution III experimental design. Fibrillation was monitored by fluorescence and infrared spectroscopy and optical microscopy. Both fragments formed fibrils at pH 1.6 and a temperature of 60 °C. The lag time and apparent …


Membrane-Based Separation Processes For Treating High Salinity Produced Waters, Kamyar Sardari Aug 2018

Membrane-Based Separation Processes For Treating High Salinity Produced Waters, Kamyar Sardari

Graduate Theses and Dissertations

Produced waters (PW) generated in the oil and gas industry within the United States often contain extreme levels of total dissolved solids (TDS). These high TDS waste streams need to be treated cost-effectively as the costs associated with the current management techniques can exceed 15 USD per barrel of discharged PW. Thermally and osmotically-driven membrane separation technologies can show promising potential for treating high TDS waste streams, as onsite low-grade waste heat may be used for their operation. In this dissertation, the application of membrane distillation (MD), forward osmosis (FO) and a hybrid FO-MD process for treating synthetic and actual …


Design Of Peptoid-Based Coating To Reduce Biofouling In Gas Exchange Devices, Neda Mahmoudi Aug 2018

Design Of Peptoid-Based Coating To Reduce Biofouling In Gas Exchange Devices, Neda Mahmoudi

Graduate Theses and Dissertations

In recent decades, membrane technology has been used commonly in biomedical area. However, membrane fouling is a widespread problem in different applications. One method to minimize fouling is through surface modification of membranes. My research explores a novel polymer to minimize nonspecific protein adsorption in biomedical applications.

It firstly focuses on grafting the electrically neutral NMEG peptoid, containing 2-methoxyethyl side chains, to polysulfone (PSU) membrane via polydopamine. Contact angle measurements indicated that the hydrophilicity of the peptoid-grafted membranes was significantly improved while the pore size and strength of the membranes remained unchanged. The modified membranes showed an improved fouling resistance …


Electrocatalytic Properties Of Ni-Fe Basedalloys Toward Oxygen Evolution Reaction, Xiaodan Cui Jul 2018

Electrocatalytic Properties Of Ni-Fe Basedalloys Toward Oxygen Evolution Reaction, Xiaodan Cui

LSU Doctoral Dissertations

In this dissertation, laser-based manufacturing was applied to develop NiFe-based alloys, with focus on their electrochemical characteristics toward oxygen evolution reaction during water electrocatalysis. The targeted electrocatalysts were designed by combining catalysis principles of absorption energy, electronic effect and geometry effect. Firstly, a one-step laser-based manufacturing method was applied to prepare a thin layer of NiFe-based electrodes with varied Ni to Fe ratios to replace high-cost noble metals as the electrocatalyst for oxygen evolution reaction (OER). Since each Ni has 0.6 d-vacancy and each Fe atom has 2.2 d-vacancies. The alloying of Ni-Fe allows electrons flowing from Ni to Fe, …


Incorporating Germanium Oxide Into The Glass Phase Of Novel Zinc/Magnesium-Based Gpcs Designed For Bone Void Filling: Evaluating Their Physical And Mechanical Properties, Basel A. Khader, Omar Rodriguez, Mark R. Towler Jul 2018

Incorporating Germanium Oxide Into The Glass Phase Of Novel Zinc/Magnesium-Based Gpcs Designed For Bone Void Filling: Evaluating Their Physical And Mechanical Properties, Basel A. Khader, Omar Rodriguez, Mark R. Towler

Chemical and Biochemical Engineering Faculty Research & Creative Works

The structural role of Germanium (Ge), when substituting for Zinc (Zn) up to 8 mol % in the 0.48SiO2-0.12CaO-0.36ZnO-0.04MgO glass series, was investigated with respect to both the glass chemistry and also the properties of glass polyalkenoate cements (GPCs) manufactured from them. The Network connectivity (NC) of the glass was calculated to increase from 1.83 to 2.42 with the addition of GeO2 (0-8 mol %). Differential thermal analysis (DTA) results confirmed an increase in the glass transition temperature (Tg) of the glass series with GeO2 content. X-ray photoelectron spectroscopy (XPS) showed an increase in …


Data-Based Nonlinear Model Identification In Economic Model Predictive Control, Laura Giuliani, Helen Durand Jul 2018

Data-Based Nonlinear Model Identification In Economic Model Predictive Control, Laura Giuliani, Helen Durand

Chemical Engineering and Materials Science Faculty Research Publications

Many chemical/petrochemical processes in industry are not completely modeled from a first-principles perspective because of the complexity of the underlying physico-chemical phenomena and the cost of obtaining more accurate, physically relevant models. System identification methods have been utilized successfully for developing empirical, though not necessarily physical, models for advanced model-based control designs such as model predictive control (MPC) for decades. However, a fairly recent development in MPC is economic model predictive control (EMPC), which is an MPC formulated with an economics-based objective function that may operate a process in a dynamic (i.e., off steady-state) fashion, in which case the details …


Reverse Flotation Separation Of Fluorite From Calcite: A Novel Reagent Scheme, Jianjun Wang, Zihan Zhou, Yuesheng Gao, Wei Sun, Yuehua Hu, Zhiyong Gao Jul 2018

Reverse Flotation Separation Of Fluorite From Calcite: A Novel Reagent Scheme, Jianjun Wang, Zihan Zhou, Yuesheng Gao, Wei Sun, Yuehua Hu, Zhiyong Gao

Michigan Tech Publications, Part 1

Fluorite (CaF2), as an important strategic mineral source, is usually separated from calcite by the common froth flotation method, but this separation is still not selective enough. The development of a selective collector and/or depressant is the key to achieving high selective separation. 1-Hydroxyethylidene-1,1-diphosphonic acid (HEDP or H4L) is widely used as an environmentally friendly water treatment reagent due to its low cost and excellent anti-scaling performance in an aqueous solution. In this study, a novel reagent scheme was developed using HEDP as a fluorite depressant and sodium oleate (NaOL) as a calcite collector for the …


Diverse Lignocellulosic Feedstocks Can Achieve High Field‐Scale Ethanol Yields While Providing Flexibility For The Biorefinery And Landscape‐Level Environmental Benefits, Yaoping Zhang, Lawrence G. Oates, Jose Serate, Dan Xie, Edward Pohlman, Yury Bukhman, Rebecca Garlock Ong, Et Al. Jul 2018

Diverse Lignocellulosic Feedstocks Can Achieve High Field‐Scale Ethanol Yields While Providing Flexibility For The Biorefinery And Landscape‐Level Environmental Benefits, Yaoping Zhang, Lawrence G. Oates, Jose Serate, Dan Xie, Edward Pohlman, Yury Bukhman, Rebecca Garlock Ong, Et Al.

Department of Chemical Engineering Publications

Increasing the diversity of lignocellulosic feedstocks accepted by a regional biorefinery has the potential to improve the environmental footprint of the facility; harvest,storage, and transportation logistics; and biorefinery economics. However, feedstocks can vary widely in terms of their biomass yields and quality characteristics (chemical composition, moisture content, etc.). To investigate how the diversity of potential biofuel cropping systems and feedstock supply might affect process and field‐scale ethanol yields, we processed and experimentally quantified ethanol production from five different herbaceous feedstocks: two annuals (corn stover and energy sorghum) and three perennials (switchgrass, miscanthus, and mixed prairie). The feedstocks werepretreated using ammonia …


Tio2 Assisted Photodegradation For Low Substrate Concentrations And Transition Metal Electron Scavengers, Hassan A. Alsaud, Ahmed E. Abibat, Roger Painter, Lonnie Sharpe, Samuel Keith Hargrove Jul 2018

Tio2 Assisted Photodegradation For Low Substrate Concentrations And Transition Metal Electron Scavengers, Hassan A. Alsaud, Ahmed E. Abibat, Roger Painter, Lonnie Sharpe, Samuel Keith Hargrove

Mechanical and Manufacturing Engineering Faculty Research

Some contaminants of emerging concern (CECs) are known to survive conventional wastewater treatment, which introduces them back to the environment, allowing them to potentially cycle into drinking water. This is especially concerning because of the inherent ability of some CECs to induce physiological effects in humans at very low doses. Advanced oxidation processes (AOPs) such as TiO2-based photocatalysis are of great interest for addressing CECs in aqueous environments. Natural water resources often contain dissolved metal cation concentrations in excess of targeted CEC concentrations. These cations may significantly adversely impact the degradation of CECs by scavenging TiO2 surface generated electrons. Consequently, …


Rates Of Cavity Filling By Liquids, Dongjin Seo, Alex M. Schrader, Szu-Ying Chen, Yair Kaufman, Thomas R. Cristiani, Steven H. Page, Peter H. Koenig, Yonas Gizaw, Dong Woog Lee, Jacob N. Israelachvili Jul 2018

Rates Of Cavity Filling By Liquids, Dongjin Seo, Alex M. Schrader, Szu-Ying Chen, Yair Kaufman, Thomas R. Cristiani, Steven H. Page, Peter H. Koenig, Yonas Gizaw, Dong Woog Lee, Jacob N. Israelachvili

Faculty Publications

Understanding the fundamental wetting behavior of liquids on surfaces with pores or cavities provides insights into the wetting phenomena associated with rough or patterned surfaces, such as skin and fabrics, as well as the development of everyday products such as ointments and paints, and industrial applications such as enhanced oil recovery and pitting during chemical mechanical polishing. We have studied, both experimentally and theoretically, the dynamics of the transitions from the unfilled/partially filled (Cassie–Baxter) wetting state to the fully filled (Wenzel) wetting state on intrinsically hydrophilic surfaces (intrinsic water contact angle < 90°, where the Wenzel state is always the thermodynamically favorable state, while a temporary metastable Cassie–Baxter state can also exist) to determine the variables that control the rates of such transitions. We prepared silicon wafers with cylindrical cavities of different geometries and immersed them in bulk water. With bright-field and confocal fluorescence microscopy, we observed the details of, and the rates associated with, water penetration into the cavities from the bulk. We find that unconnected, reentrant cavities (i.e., cavities that open up below the surface) have the slowest cavity-filling rates, while connected or non-reentrant cavities undergo very rapid transitions. Using these unconnected, reentrant cavities, we identified the variables that affect cavity-filling rates: (i) the intrinsic contact angle, (ii) …


Catalysts For Nitrogen Reduction To Ammonia, Royce D. Duda, Julie N. Renner Jul 2018

Catalysts For Nitrogen Reduction To Ammonia, Royce D. Duda, Julie N. Renner

Faculty Scholarship

The production of synthetic ammonia remains dependent on the energy- and capital-intensive Haber-Bosch process. Extensive research in molecular catalysis has demonstrated ammonia production from dinitrogen, albeit at low production rates. Mechanistic understanding of dinitrogen reduction to ammonia continues to be delineated through study of molecular catalyst structure, as well as through understanding the naturally occurring nitrogenase enzyme. The transition to Haber-Bosch alternatives through robust, heterogeneous catalyst surfaces remains an unsolved research challenge. Catalysts for electrochemical reduction of dinitrogen to ammonia are a specific focus of research, due to the potential to compete with the Haber-Bosch process and reduce associated carbon …


Modeling Soot Formation From Solid Complex Fuels, Alexander J. Josephson, Rod R. Linn, David O. Lignell Jul 2018

Modeling Soot Formation From Solid Complex Fuels, Alexander J. Josephson, Rod R. Linn, David O. Lignell

Faculty Publications

A detailed model is proposed for predicting soot formation from complex solid fuels. The proposed model resolves two particle size distributions, one for soot precursors and another for soot particles. The precursor size distribution is represented with a sectional approach while the soot particle-size distribution is represented with the method of moments and an interpolative closure method is used to resolve fractional methods. Based on established mechanisms, this model includes submodels for precursor coagulation, growth, and consumption, as well as soot nucleation, surface growth, agglomeration, and consumption. The model is validated with comparisons to experimental data for two …