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Establishment And Application Of Fractal Capillary Tube Bundle Model Of Porous Media, Zhonghua Liu, Jianing Shen, Qianhua Xiao, Zhongpei Ding, Shunpeng Zeng, Baojun Bai Nov 2018

Establishment And Application Of Fractal Capillary Tube Bundle Model Of Porous Media, Zhonghua Liu, Jianing Shen, Qianhua Xiao, Zhongpei Ding, Shunpeng Zeng, Baojun Bai

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

In view of the problem of statistical regression constant in the model of capillary tube bundles in the porous media, a capillary bundle percolation model with fractal geometry was reconstructed. The function expressions of the fractal coefficient and Kozeny constant were deduced. The relationship between the macroscopic fractal properties of porous media and the fractal dimension and the micro pore parameters were obtained. Results show: Fractal coefficient is a function of fractal dimension, maximum pore radius and minimum pore radius; The macroscopic physical properties of porous media are a function of the fractal dimension and the radius of the capillary …


Crustal Azimuthal Anisotropy Beneath The Southeastern Tibetan Plateau And Its Geodynamic Implications, Tuo Zheng, Zhifeng Ding, Jieyuan Ning, Lijun Chang, Xingchen Wang, Fansheng Kong, Kelly H. Liu, Stephen S. Gao Nov 2018

Crustal Azimuthal Anisotropy Beneath The Southeastern Tibetan Plateau And Its Geodynamic Implications, Tuo Zheng, Zhifeng Ding, Jieyuan Ning, Lijun Chang, Xingchen Wang, Fansheng Kong, Kelly H. Liu, Stephen S. Gao

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

The fast orientation and magnitude of crustal azimuthal anisotropy beneath the southeastern Tibetan Plateau and adjacent areas are measured by analyzing the sinusoidal moveout of the P to S converted phase from the Moho. Beneath the tectonically active plateau, the mean magnitude is 0.48 ±Â 0.13 s, which is about twice as large as that observed in the stable Sichuan Basin (0.23 ±Â 0.10 s). The two areas are separated by the Longmenshan fault zone, a zone of devastating earthquakes including the 12 May 2008 MW 7.9 Wenchuan earthquake. Fault orthogonal fast orientations observed in the southern Longmenshan fault …


Comprehensive Evaluation Of The Ifloods Radar Rainfall Products For Hydrologic Applications, Bong Chul Seo, Witold F. Krajewski, Felipe Quintero, Mohamed Elsaadani, Radoslaw Goska, Luciana K. Cunha, Brenda Dolan, David B. Wolff, James A. Smith, Steven A. Rutledge, Walter A. Petersen Nov 2018

Comprehensive Evaluation Of The Ifloods Radar Rainfall Products For Hydrologic Applications, Bong Chul Seo, Witold F. Krajewski, Felipe Quintero, Mohamed Elsaadani, Radoslaw Goska, Luciana K. Cunha, Brenda Dolan, David B. Wolff, James A. Smith, Steven A. Rutledge, Walter A. Petersen

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This study describes the generation and testing of a reference rainfall product created from field campaign datasets collected during the NASA Global Precipitation Measurement (GPM) mission Ground Validation Iowa Flood Studies (IFloodS) experiment. The study evaluates ground-based radar rainfall (RR) products acquired during IFloodS in the context of building the reference rainfall product. The purpose of IFloodS was not only to attain a high-quality ground-based reference for the validation of satellite rainfall estimates but also to enhance understanding of flood-related rainfall processes and the predictability of flood forecasting. We assessed the six RR estimates (IFC, Q2, CSU-DP, NWS-DP, Stage IV, …


The Missouri Miner, October 31, 2018 Oct 2018

The Missouri Miner, October 31, 2018

The Missouri Miner Newspaper

No abstract provided.


A Sensitivity Analysis For Mixed Criticality: Trading Criticality With Computational Resource, Luca Santinelli, Zhishan Guo Oct 2018

A Sensitivity Analysis For Mixed Criticality: Trading Criticality With Computational Resource, Luca Santinelli, Zhishan Guo

Computer Science Faculty Research & Creative Works

Mixing workloads with multiple criticality levels raises challenges both in timing analysis and schedulability analysis. The timing models have to characterize the different behaviors that real-time tasks can experience under the various criticality modes. Instead, the schedulability analysis has to combine every task and task interactions providing several guarantees, depending on the criticality level demanded at runtime. With this work, at first, we propose representations to model every possible system criticality mode as a combination of task criticality modes. A set of bounding functions is obtained, a bound for each mode combination thus corresponding to a system criticality level. Secondly, …


Introduction To The Finite-Difference Time-Domain (Fdtd) Technique, Bruce Archambeault Oct 2018

Introduction To The Finite-Difference Time-Domain (Fdtd) Technique, Bruce Archambeault

Electrical and Computer Engineering Faculty Research & Creative Works

No abstract provided.


Physical And Technological Aspects Of Microstrip Ebg Filter Design, Marina Koledintseva, Sergiu Radu, Joe Nuebel Oct 2018

Physical And Technological Aspects Of Microstrip Ebg Filter Design, Marina Koledintseva, Sergiu Radu, Joe Nuebel

Electrical and Computer Engineering Faculty Research & Creative Works

Some physical and technological aspects of the electromagnetic bandgap (EBG) common-mode (CM) filters are discussed. A simple EBG notch filter for CM in edge-coupled differential microstrip pair is designed using full-wave numerical electromagnetic software. Mixed-mode S-parameters of the EBG structure are analyzed as functions of its basic geometry, including size and number of EBG patches, gaps between them, geometry and position of signal traces across the EBG patches. In this work, one and two differential pairs crossing the EBG patches are considered. It is shown that the filter performance depends on various technological features, such as frequency-dispersive core and prepreg …


Quality Criteria For Electromagnetic Wave Absorbers, Konstantin N. Rozanov, Marina Y. Koledintseva Oct 2018

Quality Criteria For Electromagnetic Wave Absorbers, Konstantin N. Rozanov, Marina Y. Koledintseva

Electrical and Computer Engineering Faculty Research & Creative Works

No abstract provided.


Close Examination Of The Ground-State Casimir-Polder Interaction: Time-Ordered Versus Covariant Formalism And Radiative Corrections, C. M. Adhikari, Ulrich D. Jentschura Oct 2018

Close Examination Of The Ground-State Casimir-Polder Interaction: Time-Ordered Versus Covariant Formalism And Radiative Corrections, C. M. Adhikari, Ulrich D. Jentschura

Physics Faculty Research & Creative Works

The purpose of this paper is twofold. First, we compare, in detail, the derivation of the Casimir-Polder interaction using time-ordered perturbation theory, to the matching of the scattering amplitude using quantum electrodynamics. In the first case, a total of twelve time-ordered diagrams need to be considered, while in the second case, one encounters only two Feynman diagrams, namely, the ladder and crossed-ladder contributions. For ground-state interactions, we match the contribution of six of the time-ordered diagrams against the corresponding Feynman diagrams, showing the consistency of the two approaches. Second, we also examine the leading radiative correction to the long-range interaction, …


Meta-Learning Related Tasks With Recurrent Networks: Optimization And Generalization, Thy Nguyen, A. Steven Younger, Emmett Redd, Tayo Obafemi-Ajayi Oct 2018

Meta-Learning Related Tasks With Recurrent Networks: Optimization And Generalization, Thy Nguyen, A. Steven Younger, Emmett Redd, Tayo Obafemi-Ajayi

Electrical and Computer Engineering Faculty Research & Creative Works

There have been recent interest in meta-learning systems: I.e., networks that are trained to learn across multiple tasks. This paper focuses on optimization and generalization of a meta-learning system based on recurrent networks. The optimization investigates the influence of diverse structures and parameters on its performance. We demonstrate the generalization (robustness) of our meta-learning system to learn across multiple tasks including tasks unseen during the meta training phase. We introduce a meta-cost function (Mean Squared Fair Error) that enhances the performance of the system by not penalizing it during transitions to learning a new task. Evaluation results are presented for …


Elm-Som: A Continuous Self-Organizing Map For Visualization, Renjie Hu, Venous Roshdibenam, Hans J. Johnson, Emil Eirola, Anton Akusok, Yoan Miche, Kaj Mikael Björk, Amaury Lendasse Oct 2018

Elm-Som: A Continuous Self-Organizing Map For Visualization, Renjie Hu, Venous Roshdibenam, Hans J. Johnson, Emil Eirola, Anton Akusok, Yoan Miche, Kaj Mikael Björk, Amaury Lendasse

Engineering Management and Systems Engineering Faculty Research & Creative Works

This Paper Presents a Novel Dimensionality Reduction Technique: Elm-Som. This Technique Preserves the Intrinsic Quality of Self-Organizing Maps (Som): It is Nonlinear and Suitable for Big Data. It Also Brings Continuity to the Projection using Two Extreme Learning Machine (Elm) Models, the First One to Perform the Dimensionality Reduction and the Second One to Perform the Reconstruction. Elm-Som is Tested Successfully on Six Diverse Datasets. Regarding Reconstruction Error, Elm-Som is Comparable to Som While Bringing Continuity.


Impulsive Dynamics And Control Of The Inertia-Wheel Pendulum, Nilay Kant, Ranjan Mukherjee Oct 2018

Impulsive Dynamics And Control Of The Inertia-Wheel Pendulum, Nilay Kant, Ranjan Mukherjee

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The dynamics of the inertia-wheel pendulum, when subjected to impulsive inputs, can be described by algebraic equations. Optimal sequences of these inputs, that minimize their infinity norm, are designed for rest-to-rest maneuvers. The results are applied to the well-studied swing-up problem, and high-gain feedback is used for continuous approximation of the inputs and simulation of the impulsive dynamics. Analytical and simulation results establish a direct link between high wheel velocities during swing-up and control strategies that take the pendulum directly to the upright configuration. They also indicate that optimal trajectories resemble those of energy-based controllers and can be designed to …


Explosive Dust Test Vessel Comparison Using Pulverized Pittsburgh Coal, Jacob Miller, Jay Schafler, Phillip R. Mulligan, Robert Eades, Kyle A. Perry, Catherine E. Johnson Oct 2018

Explosive Dust Test Vessel Comparison Using Pulverized Pittsburgh Coal, Jacob Miller, Jay Schafler, Phillip R. Mulligan, Robert Eades, Kyle A. Perry, Catherine E. Johnson

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Explosions of coal dust are a major safety concern within the coal mining industry. The explosion and subsequent fires caused by coal dust can result in significant property damage, loss of life in underground coal mines and damage to coal processing facilities. The United States Bureau of Mines conducted research on coal dust explosions until 1996 when it was dissolved. In the following years, the American Society for Testing and Materials (ASTM) developed a test standard, ASTM E1226, to provide a standard test method characterizing the “explosibility” of particulate solids of combustible materials suspended in air. The research presented herein …


Effects Of Nearwall Modeling In The Improved-Delayed-Detached-Eddy-Simulation (Iddes) Methodology, Rohit Saini, Nader Karimi, Lian Duan, Amsini Sadiki, Amirfarhang Mehdizadeh Oct 2018

Effects Of Nearwall Modeling In The Improved-Delayed-Detached-Eddy-Simulation (Iddes) Methodology, Rohit Saini, Nader Karimi, Lian Duan, Amsini Sadiki, Amirfarhang Mehdizadeh

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The present study aims to assess the effects of two different underlying RANS models on overall behavior of the IDDES methodology when applied to different flow configurations ranging from fully attached (plane channel flow) to separated flows (periodic hill flow). This includes investigating prediction accuracy of first and second order statistics, response to grid refinement, grey area dynamics and triggering mechanism. Further, several criteria have been investigated to assess reliability and quality of the methodology when operating in scale resolving mode. It turns out that irrespective of the near wall modeling strategy, the IDDES methodology does not satisfy all criteria …


Radiation Detector Deadtime And Pile Up: A Review Of The Status Of Science, Shoaib Usman, Amol Patil Oct 2018

Radiation Detector Deadtime And Pile Up: A Review Of The Status Of Science, Shoaib Usman, Amol Patil

Nuclear Engineering and Radiation Science Faculty Research & Creative Works

Since the early forties, researchers from around the world have been studying the phenomenon of deadtime in radiation detectors. Many have attempted to develop models to represent this phenomenon. Two highly idealized models; paralyzable and non-paralyzable are commonly used by most individuals involved in radiation measurements. Most put little thought about the operating conditions and applicability of these ideal models for their experimental conditions. So far, there is no general agreement on the applicability of any given model for a specific detector under specific operating conditions, let alone a universal model for all detectors and all operating conditions. Further the …


From Tag To Protect: A Tag-Driven Policy Recommender System For Image Sharing, Anna Cinzia Squicciarini, Andrea Novelli, Dan Lin, Cornelia Caragea, Haoti Zhong Sep 2018

From Tag To Protect: A Tag-Driven Policy Recommender System For Image Sharing, Anna Cinzia Squicciarini, Andrea Novelli, Dan Lin, Cornelia Caragea, Haoti Zhong

Computer Science Faculty Research & Creative Works

Sharing images on social network sites has become a part of daily routine for more and more online users. However, in face of the considerable number of images shared online, it is not a trivial task for a person to manually configure proper privacy settings for each of the images that he/she uploaded. The lack of proper privacy protection during image sharing could raise many potential privacy breaches of people's private lives that they are not aware of. In this work, we propose a privacy setting recommender system to help people effortlessly set up the privacy settings for their online …


Ultralow Dispersion Multicomponent Thin-Film Chalcogenide Glass For Broadband Gradient-Index Optics, Myungkoo Kang, Andrew M. Swisher, Alexej V. Pogrebnyakov, Liu Liu, Andrew Kirk, Stephen Aiken, Laura Sisken, Charmayne Lonergan, Justin Cook, Teodor Malendevych, Fedor Kompan, Ivan Divliansky, Leonid B. Glebov, Martin C. Richardson, Clara Rivero-Baleine, Carlo G. Pantano Sep 2018

Ultralow Dispersion Multicomponent Thin-Film Chalcogenide Glass For Broadband Gradient-Index Optics, Myungkoo Kang, Andrew M. Swisher, Alexej V. Pogrebnyakov, Liu Liu, Andrew Kirk, Stephen Aiken, Laura Sisken, Charmayne Lonergan, Justin Cook, Teodor Malendevych, Fedor Kompan, Ivan Divliansky, Leonid B. Glebov, Martin C. Richardson, Clara Rivero-Baleine, Carlo G. Pantano

Materials Science and Engineering Faculty Research & Creative Works

A novel photothermal process to spatially modulate the concentration of sub-wavelength, high-index nanocrystals in a multicomponent Ge-As-Pb-Se chalcogenide glass thin film resulting in an optically functional infrared grating is demonstrated. The process results in the formation of an optical nanocomposite possessing ultralow dispersion over unprecedented bandwidth. The spatially tailored index and dispersion modification enables creation of arbitrary refractive index gradients. Sub-bandgap laser exposure generates a Pb-rich amorphous phase transforming on heat treatment to high-index crystal phases. Spatially varying nanocrystal density is controlled by laser dose and is correlated to index change, yielding local index modification to ≈+0.1 in the mid-infrared.


Toward Autonomous Wall-Climbing Robots For Inspection Of Concrete Bridges And Tunnels, Jizhong Xiao Sep 2018

Toward Autonomous Wall-Climbing Robots For Inspection Of Concrete Bridges And Tunnels, Jizhong Xiao

INSPIRE Archived Webinars

In addition to visual inspection for surface flaws, inspectors are often required to detect subsurface defects (e.g., delamination and voids) using nondestructive evaluation (NDE) instruments, such as ground penetration radar (GPR) and impact sounding device, in order to determine the structural integrity of bridges and tunnels. In these cases, access to critical locations for reliable and safe inspections is a challenge.

Since 2002, Dr. Jizhong Xiao’s group has developed four generations of wall-climbing robots for NDE inspection of bridges and tunnels. These robots combine the advantages of aerodynamic attraction and suction to achieve a desirable balance of strong adhesion and …


Solid State Nmr Spectroscopy/Imaging In Situ Measuring Devices And Methods For Calibration And Determining One Or More Quantitative Properties Of A Target Sample, Lingyu Chi, Ming Huang, Rex E. Gerald, Klaus Woelk Sep 2018

Solid State Nmr Spectroscopy/Imaging In Situ Measuring Devices And Methods For Calibration And Determining One Or More Quantitative Properties Of A Target Sample, Lingyu Chi, Ming Huang, Rex E. Gerald, Klaus Woelk

Chemistry Faculty Research & Creative Works

In situ measuring devices, methods of making the same, and methods of using the same are provided herein. The in situ measuring devices can include a capillary tube having a reference material sealed inside the capillary tube, where the capillary tube is positioned inside of a solid state or MAS NMR rotor. A target sample can also be positioned in the interior of the solid state or MAS NMR rotor but is sequestered from the reference material by a capillary tube wall. The in situ measuring devices can be used in solid state MAS NMR spectroscopy to quantify one or …


Solid State Nmr Spectroscopy/Imaging In Situ Measuring Devices And Methods For Calibration And Determining One Or More Quantitative Properties Of A Target Sampleabstract, Lingyu Chi, Ming Huang, R. Gerald Ii, Klaus Woelk Sep 2018

Solid State Nmr Spectroscopy/Imaging In Situ Measuring Devices And Methods For Calibration And Determining One Or More Quantitative Properties Of A Target Sampleabstract, Lingyu Chi, Ming Huang, R. Gerald Ii, Klaus Woelk

Chemistry Faculty Research & Creative Works

In situ measuring devices, methods of making the same, and methods of using the same are provided herein. The in situ measuring devices can include a capillary tube having a reference material sealed inside the capillary tube, where the capillary tube is positioned inside of a solid state or MAS NMR rotor. A target sample can also be positioned in the interior of the solid state or MAS NMR rotor but is sequestered from the reference material by a capillary tube wall. The in situ measuring devices can be used in solid state MAS NMR spectroscopy to quantify one or …


Icis 2017 Panel Report: Break Your Shackles! Emancipating Information Systems From The Tyranny Of Peer Review, Cecil Eng Huang Chua, Jason Bennett Thatcher, Fred Niederman, Yolande E. Chan, Elizabeth J. Davidson Sep 2018

Icis 2017 Panel Report: Break Your Shackles! Emancipating Information Systems From The Tyranny Of Peer Review, Cecil Eng Huang Chua, Jason Bennett Thatcher, Fred Niederman, Yolande E. Chan, Elizabeth J. Davidson

Business and Information Technology Faculty Research & Creative Works

The paper presents the report of a panel that debated the review process in the information systems (IS) discipline at ICIS 2017 in Seoul, Korea. The panel asked the fundamental question of whether we need to rethink the way we review papers in the discipline. The panelists partnered with the audience to explore some reviewing limitations in IS today and the ways that reviewing in the discipline might change to address some of its difficulties. We first report key concerns with modern reviewing. We then present arguments for and against three proposals (i.e., paying for reviews, mandatory reviews, and open …


Metaphysics Or Metaphors For The Anthropocene? Scientific Naturalism And The Agency Of Things, Patrick Gamez Sep 2018

Metaphysics Or Metaphors For The Anthropocene? Scientific Naturalism And The Agency Of Things, Patrick Gamez

Arts, Languages and Philosophy Faculty Research & Creative Works

In this paper, I provide the outlines of an alternative meta philosophical orientation for Continental philosophy, namely, a form of scientific naturalism that has proximate roots in the work of Bachelard and Althusser. I describe this orientation as an "alternative" insofar as it provides a framework for doing justice to some of the motivations behind the recent revival of metaphysics in Continental philosophy, in particular its ecological-ethical motivations. In the second section of the paper, I demonstrate how ecological-ethical issues motivate new metaphysicians like Bruno Latour, Jane Bennett, Timothy Morton, Ian Bogost, and Graham Harman to impute to objects real …


Missouri S&T Magazine Fall/Winter 2018, Missouri S&T Marketing And Communications Department, Miner Alumni Association Sep 2018

Missouri S&T Magazine Fall/Winter 2018, Missouri S&T Marketing And Communications Department, Miner Alumni Association

Missouri S&T Magazine

No abstract provided.


Gravitational Effects In G -Factor Measurements And High-Precision Spectroscopy: Limits Of Einstein's Equivalence Principle, Ulrich D. Jentschura Sep 2018

Gravitational Effects In G -Factor Measurements And High-Precision Spectroscopy: Limits Of Einstein's Equivalence Principle, Ulrich D. Jentschura

Physics Faculty Research & Creative Works

We study the interplay of general relativity, the equivalence principle, and high-precision experiments involving atomic transitions and g-factor measurements. In particular, we derive a generalized Dirac Hamiltonian, which describes both the gravitational coupling for weak fields and the electromagnetic coupling, e.g., to a central Coulomb field. An approximate form of this Hamiltonian is used to derive the leading gravitational corrections to transition frequencies and g factors. The position dependence of atomic transitions is shown to be compatible with the equivalence principle, up to a very good approximation. The compatibility of g-factor measurements requires a deeper subtle analysis in order to …


Graphene-Based Materials For The Fast Removal Of Cytokines From Blood Plasma, Mykola Seredych, Bernard Haines, Viktoriia Sokolova, Paul Cheung, Fayan Meng, Lon Stone, Lyuba Mikhalovska, Sergey Mikhalovsky, Vadym Mochalin, Yury Gogotsi Aug 2018

Graphene-Based Materials For The Fast Removal Of Cytokines From Blood Plasma, Mykola Seredych, Bernard Haines, Viktoriia Sokolova, Paul Cheung, Fayan Meng, Lon Stone, Lyuba Mikhalovska, Sergey Mikhalovsky, Vadym Mochalin, Yury Gogotsi

Chemistry Faculty Research & Creative Works

There is a range of medical conditions, which include acute organ failure, bacterial and viral infection, and sepsis, that result in overactivation of the inflammatory response of the organism and release of proinflammatory cytokines into the bloodstream. Fast removal of these cytokines from blood circulation could offer a potentially efficient treatment of such conditions. This study aims at the development and assessment of novel biocompatible graphene-based adsorbents for blood purification from proinflammatory cytokines. These graphene-based materials were chosen on the basis of their surface accessibility for small molecules further facilitated by the interlayer porosity, which is comparable to the size …


A Distributed Semi-Supervised Platform For Dnase-Seq Data Analytics Using Deep Generative Convolutional Networks, Shayan Shams, Richard Platania, Joohyun Kim, Jian Zhang, Kisung Lee, Seungwon Yang, Seung Jong Park Aug 2018

A Distributed Semi-Supervised Platform For Dnase-Seq Data Analytics Using Deep Generative Convolutional Networks, Shayan Shams, Richard Platania, Joohyun Kim, Jian Zhang, Kisung Lee, Seungwon Yang, Seung Jong Park

Computer Science Faculty Research & Creative Works

A deep learning approach for analyzing DNase-seq datasets is presented, which has promising potentials for unraveling biological underpinnings on transcription regulation mechanisms. Further understanding of these mechanisms can lead to important advances in life sciences in general and drug, biomarker discovery, and cancer research in particular. Motivated by recent remarkable advances in the field of deep learning, we developed a platform, Deep Semi-Supervised DNase-seq Analytics (DSSDA). Primarily empowered by deep generative Convolutional Networks (ConvNets), the most notable aspect is the capability of semi-supervised learning, which is highly beneficial for common biological settings often plagued with a less sufficient number of …


Additive Manufacturing Of Metal Bandpass Filters For Future Radar Receivers, Bradley Grothaus, Dane Huck, Austin T. Sutton, Ming-Chuan Leu, Ben Brown Aug 2018

Additive Manufacturing Of Metal Bandpass Filters For Future Radar Receivers, Bradley Grothaus, Dane Huck, Austin T. Sutton, Ming-Chuan Leu, Ben Brown

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Selective laser melting (SLM) is a powder-bed fusion (PBF) process that bonds successive layers of powder with a laser to create components directly from computer-aided design (CAD) files. The additive nature of the SLM process in addition to the use of fine powders facilitates the construction of complex geometries, which has captured the attention of those involved in the design of bandpass filters for radar applications. However, a significant drawback of SLM is its difficulty in fabricating parts with overhangs necessitating the use of support structures, which, if not removed, can greatly impact the performance of bandpass filters. Therefore, in …


Recyclability Of 304l Stainless Steel In The Selective Laser Melting Process, Austin T. Sutton, Caitlin S. Kriewall, Ming-Chuan Leu, Joseph William Newkirk Aug 2018

Recyclability Of 304l Stainless Steel In The Selective Laser Melting Process, Austin T. Sutton, Caitlin S. Kriewall, Ming-Chuan Leu, Joseph William Newkirk

Mechanical and Aerospace Engineering Faculty Research & Creative Works

During part fabrication by selective laser melting (SLM), a powder-bed fusion process in Additive Manufacturing (AM), a large amount of energy is input from the laser into the melt pool, causing generation of spatter and condensate, both of which have the potential to settle in the surrounding powder-bed compromising its reusability. In this study, 304L stainless steel powder is subjected to five reuses in the SLM process to assess its recyclability through characterization of both powder and mechanical properties. Powder was characterized morphologically by particle size distribution measurements, oxygen content with inert gas fusion analysis, and phase identification by X-ray …


Effect Of Environmental Variables On Ti-64 Am Simulation Results, Aaron Flood, Frank W. Liou Aug 2018

Effect Of Environmental Variables On Ti-64 Am Simulation Results, Aaron Flood, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In metal AM the environment is critical and therefore care should be taken to ensure that the simulation matches reality. This paper will investigate the effect that various environmental factors have on the results of the simulation. This will help to determine their importance in the simulation setup. The material properties which relate to this are the convective coefficient and the emissivity. These material properties will be investigated to determine their effect on the outcome of the simulation. In addition to these properties, the size of the substrate will be investigated to determine if any results are altered. Lastly, the …


Effects Of Thermal Camera Resolution On Feature Extraction In Selective Laser Melting, Xin Wang, Cody S. Lough, Douglas A. Bristow, Edward C. Kinzel, Robert G. Landers Aug 2018

Effects Of Thermal Camera Resolution On Feature Extraction In Selective Laser Melting, Xin Wang, Cody S. Lough, Douglas A. Bristow, Edward C. Kinzel, Robert G. Landers

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Selective Laser Melting (SLM) is a common additive manufacturing process which uses a laser energy source to fuse metal powder layer by layer. Engineering properties and microstructure are related to the part’s thermal history. It is important to measure the thermal history in-situ to qualify parts and provide the sensing which is necessary for process control. A common measurement tool for this purpose is a thermal camera that records the thermal emission of the part’s surface.

This study investigates the effects of spatial sampling resolution of thermal cameras when monitoring the temperature in SLM processes. High-fidelity simulation of an SLM …