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Missouri University of Science and Technology

Mechanical and Aerospace Engineering Faculty Research & Creative Works

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Full-Text Articles in Physical Sciences and Mathematics

Sharprazor: Automatic Removal Of Hair And Ruler Marks From Dermoscopy Images, Reda Kasmi, Jason Hagerty, Reagan Harris Young, Norsang Lama, Januka Nepal, Jessica Miinch, William V. Stoecker, R. Joe Stanley Apr 2023

Sharprazor: Automatic Removal Of Hair And Ruler Marks From Dermoscopy Images, Reda Kasmi, Jason Hagerty, Reagan Harris Young, Norsang Lama, Januka Nepal, Jessica Miinch, William V. Stoecker, R. Joe Stanley

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Background: The removal of hair and ruler marks is critical in handcrafted image analysis of dermoscopic skin lesions. No other dermoscopic artifacts cause more problems in segmentation and structure detection. Purpose: The aim of the work is to detect both white and black hair, artifacts and finally inpaint correctly the image. Method: We introduce a new algorithm: SharpRazor, to detect hair and ruler marks and remove them from the image. Our multiple-filter approach detects hairs of varying widths within varying backgrounds, while avoiding detection of vessels and bubbles. The proposed algorithm utilizes grayscale plane modification, hair enhancement, segmentation using tri-directional …


Jointly-Learnt Networks For Future Action Anticipation Via Self-Knowledge Distillation And Cycle Consistency, Md Moniruzzaman, Zhaozheng Yin, Zhihai He, Ming-Chuan Leu, Ruwen Qin Jan 2022

Jointly-Learnt Networks For Future Action Anticipation Via Self-Knowledge Distillation And Cycle Consistency, Md Moniruzzaman, Zhaozheng Yin, Zhihai He, Ming-Chuan Leu, Ruwen Qin

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Future action anticipation aims to infer future actions from the observation of a small set of past video frames. In this paper, we propose a novel Jointly learnt Action Anticipation Network (J-AAN) via Self-Knowledge Distillation (Self-KD) and cycle consistency for future action anticipation. In contrast to the current state-of-the-art methods which anticipate the future actions either directly or recursively, our proposed J-AAN anticipates the future actions jointly in both direct and recursive ways. However, when dealing with future action anticipation, one important challenge to address is the future's uncertainty since multiple action sequences may come from or be followed by …


Modeling Of Cloud-Based Digital Twins For Smart Manufacturing With Mt Connect, Liwen Hu, Ngoc-Tu Nguyen, Wenjin Tao, Ming-Chuan Leu, Xiaoqing Frank Liu, Rakib Shahriar, S M Nahian Al Sunny Jun 2018

Modeling Of Cloud-Based Digital Twins For Smart Manufacturing With Mt Connect, Liwen Hu, Ngoc-Tu Nguyen, Wenjin Tao, Ming-Chuan Leu, Xiaoqing Frank Liu, Rakib Shahriar, S M Nahian Al Sunny

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The common modeling of digital twins uses an information model to describe the physical machines. The integration of digital twins into productive cyber-physical cloud manufacturing (CPCM) systems imposes strong demands such as reducing overhead and saving resources. In this paper, we develop and investigate a new method for building cloud-based digital twins (CBDT), which can be adapted to the CPCM platform. Our method helps reduce computing resources in the information processing center for efficient interactions between human users and physical machines. We introduce a knowledge resource center (KRC) built on a cloud server for information intensive applications. An information model …


Worker Activity Recognition In Smart Manufacturing Using Imu And Semg Signals With Convolutional Neural Networks, Wenjin Tao, Ze-Hao Lai, Ming-Chuan Leu, Zhaozheng Yin Jun 2018

Worker Activity Recognition In Smart Manufacturing Using Imu And Semg Signals With Convolutional Neural Networks, Wenjin Tao, Ze-Hao Lai, Ming-Chuan Leu, Zhaozheng Yin

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In a smart manufacturing system involving workers, recognition of the worker's activity can be used for quantification and evaluation of the worker's performance, as well as to provide onsite instructions with augmented reality. In this paper, we propose a method for activity recognition using Inertial Measurement Unit (IMU) and surface electromyography (sEMG) signals obtained from a Myo armband. The raw 10-channel IMU signals are stacked to form a signal image. This image is transformed into an activity image by applying Discrete Fourier Transformation (DFT) and then fed into a Convolutional Neural Network (CNN) for feature extraction, resulting in a high-level …


High-Frequency Instabilities Of Stationary Crossflow Vortices In A Hypersonic Boundary Layer, Fei Li, Meelan Choudhari, Pedro Paredes-Gonzalez, Lian Duan Sep 2016

High-Frequency Instabilities Of Stationary Crossflow Vortices In A Hypersonic Boundary Layer, Fei Li, Meelan Choudhari, Pedro Paredes-Gonzalez, Lian Duan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Hypersonic boundary layer flows over a circular cone at moderate incidence angle can support strong crossflow instability in between the windward and leeward rays on the plane of symmetry. Due to more efficient excitation of stationary crossflow vortices by surface roughness, such boundary layer flows may transition to turbulence via rapid amplification of the high-frequency secondary instabilities of finite-amplitude stationary crossflow vortices. The amplification characteristics of these secondary instabilities are investigated for crossflow vortices generated by an azimuthally periodic array of roughness elements over a 7° half-angle circular cone in a Mach 6 free stream. The analysis is based on …


Geometric Consideration Of Nanostructures For Energy Storage Systems, Jonghyun Park, Jie Li, Wei Lu, Ann Marie Sastry Jan 2016

Geometric Consideration Of Nanostructures For Energy Storage Systems, Jonghyun Park, Jie Li, Wei Lu, Ann Marie Sastry

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Battery performance and its fade are determined by various aspects such as the transport of ions and electrons through heterogeneous internal structures; kinetic reactions at the interfaces; and the corresponding interplay between mechanical, chemical, and thermal responses. The fundamental factor determining this complex multiscale and multiphysical nature of a battery is the geometry of active materials. In this work, we systematically consider the tradeoffs among a selection of limiting geometries of media designed to store ions or other species via a diffusion process. Specifically, we begin the investigation by considering diffusion in spheres, rods, and plates at the particle level, …


Silicon-Wall Interfacial Free Energy Via Thermodynamics Integration, Wan Shou, Heng Pan Jan 2016

Silicon-Wall Interfacial Free Energy Via Thermodynamics Integration, Wan Shou, Heng Pan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

We compute the interfacial free energy of a silicon system in contact with flat and structured walls by molecular dynamics simulation. The thermodynamics integration method, previously applied to Lennard-Jones potentials [R. Benjamin and J. Horbach, J. Chem. Phys. 137, 044707 (2012)], has been extended and implemented in Tersoff potentials with two-body and three-body interactions taken into consideration. The thermodynamic integration scheme includes two steps. In the first step, the bulk Tersoff system is reversibly transformed to a state where it interacts with a structureless flat wall, and in a second step, the flat structureless wall is reversibly transformed into an …


Ionic And Electronic Conductivities Of Atomic Layer Deposition Thin Film Coated Lithium Ion Battery Cathode Particles, Rajankumar L. Patel, Jonghyun Park, Xinhua Liang Jan 2016

Ionic And Electronic Conductivities Of Atomic Layer Deposition Thin Film Coated Lithium Ion Battery Cathode Particles, Rajankumar L. Patel, Jonghyun Park, Xinhua Liang

Mechanical and Aerospace Engineering Faculty Research & Creative Works

It is imperative to ascertain the ionic and electronic components of the total conductivity of an electrochemically active material. A blocking technique, called the “Hebb-Wagner method”, is normally used to explain the two components (ionic and electronic) of a mixed conductor, in combination with the complex ac impedance method and dc polarization measurements. CeO2 atomic layer deposition (ALD)-coated and uncoated, LiMn2O4 (LMO) and LiMn1.5Ni0.5O4 (LMNO) powders were pressed into pellets and then painted with silver to act as a blocking electrode. The electronic conductivities were derived from the currents obtained using …


Crystallization In Nano-Confinement Seeded By A Nanocrystal -- A Molecular Dynamics Study, Heng Pan, Costas Grigoropoulos Jan 2014

Crystallization In Nano-Confinement Seeded By A Nanocrystal -- A Molecular Dynamics Study, Heng Pan, Costas Grigoropoulos

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Seeded crystallization and solidification in nanoscale confinement volumes have become an important and complex topic. Due to the complexity and limitations in observing nanoscale crystallization, computer simulation can provide valuable details for supporting and interpreting experimental observations. In this article, seeded crystallization from nano-confined liquid, as represented by the crystallization of a suspended gold nano-droplet seeded by a pre-existing gold nanocrystal seed, was investigated using molecular dynamics simulations in canonical (NVT) ensemble. We found that the crystallization temperature depends on nano-confinement volume, crystal orientation, and seed size as explained by classical two-sphere model and Gibbs-Thomson effect.


Nonlinear Development And Secondary Instability Of Traveling Crossflow Vortices, Fei Li, Meelan M. Choudhari, Lian Duan, Chau-Lyan Chang Jan 2014

Nonlinear Development And Secondary Instability Of Traveling Crossflow Vortices, Fei Li, Meelan M. Choudhari, Lian Duan, Chau-Lyan Chang

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Building upon the prior research targeting the laminar breakdown mechanisms associated with stationary crossflow instability over a swept-wing configuration, this paper investigates the secondary instability of traveling crossflow modes as an alternate scenario for transition. For the parameter range investigated herein, this alternate scenario is shown to be viable unless the initial amplitudes of the traveling crossflow instability are lower than those of the stationary modes by considerably more than one order of magnitude. The linear growth predictions based on the secondary instability theory are found to agree well with both parabolized stability equations and direct numerical simulation, and the …


Robustness Analysis Of Slow Learning In Iterative Learning Control Systems, John R. Singler, Douglas A. Bristow Jan 2011

Robustness Analysis Of Slow Learning In Iterative Learning Control Systems, John R. Singler, Douglas A. Bristow

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This paper examines robust stability and robust transient growth in Iterative Learning Control (ILC). It is well known that small perturbations in system dynamics can result in very large transient growth of some ILC systems. Even larger perturbations can result in instability. One ad hoc technique commonly employed to improve robustness is to slow the learning rate by reducing the learning filter gain or lowpass filtering the error signal. Here, pseudospectra analysis is used to analyze the robustness of ILC algorithms with slow learning. It is found that robustness bounds can be increased and transient growth decreased with decreasing learning …


Towards Transient Growth Analysis And Design In Iterative Learning Control, Douglas A. Bristow, John R. Singler Jan 2011

Towards Transient Growth Analysis And Design In Iterative Learning Control, Douglas A. Bristow, John R. Singler

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In this article the problem of bounding transient growth in iterative learning control (ILC) is examined. While transient growth is not a desirable property, the alternative, robust monotonic convergence, leads to fundamental performance limitations. to circumvent these limitations, this article considers the possibility that some transient growth, if properly limited, is a viable and practical option. Towards this end, this article proposes tools for analysing worst-case transient growth in ILC. the proposed tools are based on pseudospectra analysis, which is extended to apply to ILC of uncertain systems. Two practical problems in norm-optimal ILC weighting parameter design are considered. Using …


Analysis Of Transient Growth In Iterative Learning Control Using Pseudospectra, Douglas A. Bristow, John R. Singler Dec 2009

Analysis Of Transient Growth In Iterative Learning Control Using Pseudospectra, Douglas A. Bristow, John R. Singler

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In this paper we examine the problem of transient growth in Iterative Learning Co ntrol (ILC). Transient growth is generally avoided in design by using robust monotonic convergence (RMC) criteria. However, RMC leads to fundamental performance limitations. We consider the possibility of allowing safe transient growth in ILC algorithms as a means to circumvent these limitations. Here the pseudospectra is used for the first time to study transient growth in ILC. Basic properties of the pseudospectra that are relevant to the ILC problem are presented. Two ILC design problems are considered and examined using pseduospectra. The pseudospectra provides new results …


Three-Dimensional Modeling Of The Plasma Arc In Arc Welding, Gu Xu, J. Hu, Hai-Lung Tsai Nov 2008

Three-Dimensional Modeling Of The Plasma Arc In Arc Welding, Gu Xu, J. Hu, Hai-Lung Tsai

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Most previous three-dimensional modeling on gas tungsten arc welding (GTAW) and gas metal arc welding (GMAW) focuses on the weld pool dynamics and assumes the two-dimensional axisymmetric Gaussian distributions for plasma arc pressure and heat flux. In this article, a three-dimensional plasma arc model is developed, and the distributions of velocity, pressure, temperature, current density, and magnetic field of the plasma arc are calculated by solving the conservation equations of mass, momentum, and energy, as well as part of the Maxwell's equations. This three-dimensional model can be used to study the nonaxisymmetric plasma arc caused by external perturbations such as …


Risk Assessment In Early Software Design Based On The Software Function-Failure Design Method, Jayson P. Vucovich, Robert B. Stone, Xiaoqing Frank Liu, Irem Y. Tumer Aug 2007

Risk Assessment In Early Software Design Based On The Software Function-Failure Design Method, Jayson P. Vucovich, Robert B. Stone, Xiaoqing Frank Liu, Irem Y. Tumer

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Potential software failures present a sizable risk element in the design and development of many systems. In this paper, we augment the Software Function-Failure Design method, which is capable of predicting potential software failures in the very early stages of design, with the Risk in Early Design technique. This synergistic combination allows a risk assessment to be conducted at an early time in the software development process when traditional techniques are not applicable. The results are concise risk statements regarding the potential failure of functionalities with likelihood and consequence quantifications that can be used as part of a risk management …


Grouping Www Image Search Results By Novel Inhomogeneous Clustering Method, Gu Xu, Zhiwei Li, Mingjing Li, Wei-Ying Ma, Hong-Jiang Zhang Jan 2005

Grouping Www Image Search Results By Novel Inhomogeneous Clustering Method, Gu Xu, Zhiwei Li, Mingjing Li, Wei-Ying Ma, Hong-Jiang Zhang

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In this paper, a novel inhomogeneous clustering method is proposed for grouping web images. It is used to re-organize the search result of web image search engines into a hierarchical structure so that the users can conveniently browse the search result. This method takes into account various features associated with web images, and treats them in different ways. For the surrounding text extracted from the containing web pages, co-clustering approach is adopted; for low-level features of the image content and other features, one-way clustering approach is adopted. The clustering results of different approaches are combined together to produce the final …


Object-Oriented Modeling And Fault Detection Of A Powder Feeder For A Laser Metal Deposition System, Robert G. Landers, Michael Gene Hilgers, Frank W. Liou, Bruce M. Mcmillin Aug 2002

Object-Oriented Modeling And Fault Detection Of A Powder Feeder For A Laser Metal Deposition System, Robert G. Landers, Michael Gene Hilgers, Frank W. Liou, Bruce M. Mcmillin

Mechanical and Aerospace Engineering Faculty Research & Creative Works

One of the most critical components of a laser metal deposition system is the powder feeder unit. Techniques are required to efficiently design and analyze these systems and to ensure fault tolerance during the operation. In this paper, a model of the powder feeder unit, based on object-oriented abstractions of it components, is developed. This model is modular in that specific components can be efficiently updated or replaced with components that perform a similar function. In addition, the model can be used for simulation allowing for efficient design and analysis. Assurance of the correctness of the powder feeder system is …


Object-Oriented Modeling And Fauly Detection Of A Powder Feeder For A Laser Metal Deposition System, Robert G. Landers, Michael Gene Hilgers, Frank W. Liou, Bruce M. Mcmillin Aug 2002

Object-Oriented Modeling And Fauly Detection Of A Powder Feeder For A Laser Metal Deposition System, Robert G. Landers, Michael Gene Hilgers, Frank W. Liou, Bruce M. Mcmillin

Mechanical and Aerospace Engineering Faculty Research & Creative Works

One of the most critical components of a laser metal deposition system is the powder feeder unit. Techniques are required to efficiently design and analyze these systems and to ensure fault tolerance during the operation. In this paper, a model of the powder feeder unit, based on object- oriented abstractions of it components, is developed. This model is modular in that specific components can be efficiently updated or replaced with components that perform a similar function. In addition, the model can be used for simulation allowing for efficient design and analysis. Assurance of the correctness of the powder feeder system …


Motion Based Event Recognition Using Hmm, Gu Xu, Yu-Fei Ma, Hong-Jiang Zhang, Shiqiang Yang Jan 2002

Motion Based Event Recognition Using Hmm, Gu Xu, Yu-Fei Ma, Hong-Jiang Zhang, Shiqiang Yang

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Motion is an important cue for video understanding and is widely used in many semantic video analyses. We present a new motion representation scheme in which motion in a video is represented by the responses of frames to a set of motion filters. Each of these filters is designed to be most responsive to a type of dominant motion. Then we employ hidden Markov models (HMMs) to characterize the motion patterns based on these features and thus classify basketball video into 16 events. The evaluation by human satisfaction rate to classification result is 75%, demonstrating effectiveness of the proposed approach …


Dynamics Of Poly(Vinyl Acetate)-D₃ On Silica, Robert D. O'Connor, Frank D. Blum, Gu Xu Jan 2001

Dynamics Of Poly(Vinyl Acetate)-D₃ On Silica, Robert D. O'Connor, Frank D. Blum, Gu Xu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Poly(vinyl acetate) (PVAc) is an important polymer in applications because of both its bulk and surface characteristics. Its chain architecture gives it a low Tg and, generally, good qualities for processing and applications, which include paints, adhesives, thin films and surface coatings. In this study, we investigate the surface dynamics of PVAc absorbed onto silica with deuterium nuclear magnetic resonance (2H NMR). For dynamics studies, 2H NMR is an excellent technique because it uses an innocuous probe that can report on correlation times (τc) from approximately 10-8 s to 10 s. We report the use of two-dimensional exchange NMR (2D-X) …


A System For Collecting Milligram Quantities Of Cloud Condensation Nuclei, Darryl J. Alofs, Donald E. Hagen, Steven D. Medley, Daniel R. White, John L. Schmitt, Allen L. Williams Jan 1997

A System For Collecting Milligram Quantities Of Cloud Condensation Nuclei, Darryl J. Alofs, Donald E. Hagen, Steven D. Medley, Daniel R. White, John L. Schmitt, Allen L. Williams

Mechanical and Aerospace Engineering Faculty Research & Creative Works

An Experimental System to Collect Cloud Condensation Nuclei (CCN) Onto Filters in Amounts Sufficient for Chemical Analysis is Described. This Experimental Apparatus is Designed to Process Ambient Air at a Rate of More Than 1 M3/min. Two Identical Systems Have Been Built. One is Installed in a Laboratory at Rolla, MO. the Other is Installed on an 11 M Long Trailer. the System Isolates Three Size Classes of CCN, Having Mass Median Diameters of 0.27, 0.12, and 0.075 Μm, Respectively, and Mass Collection Rates of 11.5, 1.28, and 0.13 Mg/day, Respectively. the above Sizes and Collection Rates Are Obtained from …


Intercomparison Between Commercial Condensation Nucleus Counters And An Alternating Temperature Gradient Cloud Chamber, Darryl J. Alofs, C. K. Lutrus, Donald E. Hagen Jan 1995

Intercomparison Between Commercial Condensation Nucleus Counters And An Alternating Temperature Gradient Cloud Chamber, Darryl J. Alofs, C. K. Lutrus, Donald E. Hagen

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Three Commercial CNC Counters (TSI Models 3010, 3022A, and 3025A) Are Compared with an Alternating Temperature Gradient Cloud Chamber (ALGR). Electrically Size Classified Aerosols of Sodium Chloride and Silver Are Used. Diffusional Losses within the ALGR Are Much Larger Than for the TSI Instruments: Therefore the ALGR Concentrations Are Corrected for Internal Diffusional Losses, But the TSI Instruments Are Not. the Particle Size Range Tested is 4–90 Nm. for Sodium Chloride, the TSI Concentrations Agreed Fairly Well with the Corrected ALGR at Larger Sizes, and Were Below the Corrected ALGR at Smaller Sizes. the Electrical Aerosol Classifier (EAC) Setting at …


Identification Of Cutting Force In End Milling Operations Using Recurrent Neural Networks, Q. Xu, K. Krishnamurthy, Bruce M. Mcmillin, Wen Feng Lu Jun 1994

Identification Of Cutting Force In End Milling Operations Using Recurrent Neural Networks, Q. Xu, K. Krishnamurthy, Bruce M. Mcmillin, Wen Feng Lu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The problem of identifying the cutting force in end milling operations is considered in this study. Recurrent neural networks are used here and are trained using a recursive least squares training algorithm. Training results for data obtained from a SAJO 3-axis vertical milling machine for steady slot cuts are presented. The results show that a recurrent neural network can learn the functional relationship between the feed rate and steady-state average resultant cutting force very well. Furthermore, results for the Mackey-Glass time series prediction problem are presented to illustrate the faster learning capability of the neural network scheme presented here


A Recursive Least Squares Training Algorithm For Multilayer Recurrent Neural Networks, Q. Xu, K. Krishnamurthy, Bruce M. Mcmillin, Wen Feng Lu Jun 1994

A Recursive Least Squares Training Algorithm For Multilayer Recurrent Neural Networks, Q. Xu, K. Krishnamurthy, Bruce M. Mcmillin, Wen Feng Lu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Recurrent neural networks have the potential to perform significantly better than the commonly used feedforward neural networks due to their dynamical nature. However, they have received less attention because training algorithms/architectures have not been well developed. In this study, a recursive least squares algorithm to train recurrent neural networks with an arbitrary number of hidden layers is developed. The training algorithm is developed as an extension of the standard recursive estimation problem. Simulated results obtained for identification of the dynamics of a nonlinear dynamical system show promising results.


Neural Modeling And Control Of A Distillation Column, James Edward Steck, K. Krishnamurthy, Bruce M. Mcmillin, Gary G. Leininger Jul 1992

Neural Modeling And Control Of A Distillation Column, James Edward Steck, K. Krishnamurthy, Bruce M. Mcmillin, Gary G. Leininger

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Control of a nine-stage three-component distillation column is considered. The control objective is achieved using a neural estimator and a neural controller. The neural estimator is trained to represent the chemical process accurately, and the neural controller is trained to give an input to the chemical process which will yield the desired output. Training of both the neural networks is accomplished using a recursive least squares training algorithm implemented on an Intel iPSC/2 multicomputer (hypercube). Simulated results are presented for a numerical example.


Determining The Chemical Composition Of Cloud Condensation Nuclei, Allen L. Williams, Jane E. Rothert, Kent E. Mcclure, Darryl J. Alofs, Donald E. Hagen, Daniel R. White, A. R. Hopkins, Max B. Trueblood Feb 1992

Determining The Chemical Composition Of Cloud Condensation Nuclei, Allen L. Williams, Jane E. Rothert, Kent E. Mcclure, Darryl J. Alofs, Donald E. Hagen, Daniel R. White, A. R. Hopkins, Max B. Trueblood

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This second progress report describes the status of the project one and one-half years after the start. The goal of the project is to develop the instrumentation to collect cloud condensation nuclei (CCN) in sufficient amounts to determine their chemical composition, and to survey the CCN composition in different climates through a series of field measurements. Our approach to CCN collection is to first form droplets on the nuclei under simulated cloud humidity conditions, which is the only known method of identifying CCN from the background aerosol. Under cloud chamber conditions, the droplets formed become larger than the surrounding aerosol, …


Hydration Behavior Of Laser Dye Aerosols Of Mixed Composition Having High Critical Supersaturations, Max B. Trueblood, Donald E. Hagen, Darryl J. Alofs Jan 1992

Hydration Behavior Of Laser Dye Aerosols Of Mixed Composition Having High Critical Supersaturations, Max B. Trueblood, Donald E. Hagen, Darryl J. Alofs

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This Study Concerns Aerosol Particles of Mixed Composition. the Particles Contain a Water Insoluble Core (Polystyrene Latex), Surrounded by a Water Soluble Shell (Various Fluorescent Dyes). a Collison Nebulizer and an Electrostatic Aerosol Classifier Are Used to Prepare the Aerosol; its Critical Supersaturation Spectrum is Measured with a Diffusion Cloud Chamber. Experiments Were Done using Four Different Dyes (Disodium Fluorescein, Sulforhodamine 640, Sulforhodamine B and Rhodamine 560 Chloride) with Five Different Polystyrene Latex Sphere Sizes. the Results Indicate that a Kohler-Type Behavior is Obeyed. This Technique of Putting a Soluble Coating Onto an Insoluble Core is Found to Be a …


A Study Of The Hydration Properties Of Selected Laser Dye Aerosols Including Continuous-Flow Parallel Plate And Alternating-Gradient Thermal Diffusion Cloud Chamber Measurements In The High Supersaturation Regime, Donald E. Hagen, Max B. Trueblood, Darryl J. Alofs Jan 1990

A Study Of The Hydration Properties Of Selected Laser Dye Aerosols Including Continuous-Flow Parallel Plate And Alternating-Gradient Thermal Diffusion Cloud Chamber Measurements In The High Supersaturation Regime, Donald E. Hagen, Max B. Trueblood, Darryl J. Alofs

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The Hydration Behavior of Aerosols made Up of Various Fluorescent Dyes when Exposed to Water Saturation or Supersaturated Conditions Has Been Studied. Critical Supersaturation Spectra Are Reported. the Dyes Are Found to Behave as High Molecular Weight Ionic Compounds that Obey Kohler Theory. their Relevant Kohler Parameters Are Measured. This Study Makes Use of and Compares Results from the Isothermal Hazecontinuous-Flowand Alternating-Gradient Thermal Diffusion Cloud Chambers. the Ability of the Continuous-Flow Thermal Diffusion Chamber to Operate Correctly at High Supersaturations is Shown. © 1990 Elsevier Science Publishing Co., Inc.


Measured Spectra Of The Hygroscopic Fraction Of Atmospheric Aerosol Particles, Darryl J. Alofs, Donald E. Hagen, Max B. Trueblood Feb 1989

Measured Spectra Of The Hygroscopic Fraction Of Atmospheric Aerosol Particles, Darryl J. Alofs, Donald E. Hagen, Max B. Trueblood

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The relation between dry diameter (X0) and critical supersaturation (Sc) for atmospheric submicron aerosol particles is investigated using a long term air sampling program at Rolla, Missouri. The particles are passed through an electrostatic aerosol size classifier, and then through an isothermal haze chamber. Results are reported in terms of an apparent volume fraction of soluble material, εv defined such that for particles composed only of ammonium sulfate and water insoluble compounds, εv is the actual volume fraction of soluble material. The probability distribution of εv is found to be approximately Gaussian in …


Measured Spectra Of The Hygroscopic Fraction Of Atmospheric Aerosol Particles, Darryl J. Alofs, Donald E. Hagen, Max B. Trueblood Jan 1989

Measured Spectra Of The Hygroscopic Fraction Of Atmospheric Aerosol Particles, Darryl J. Alofs, Donald E. Hagen, Max B. Trueblood

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The Relation between Dry Diameter (Xo) and Critical Supersaturation (Sc) for Atmospheric Submicron Aerosol Particles is Investigated. the Particles Are Passed through an Electrostatic Aerosol Size Classifier, and Then through an Isothermal Haze Chamber. Results Are Reported in Terms of an Apparent Volume Fraction of Soluble Material, Εv, Defined Such that for Particles Composed Only of Ammonium Sulfate and Water Insoluble Compounds, Εv is the Actual Volume Fraction of Soluble Material. the Probability Distribution of Εv is Found to Be Approximately Gaussian in the Εv Range 0.2 to 1.3. the Mean Εv is 0.5, for Electrostatic Aerosol Classifier Settings of …