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Customized Boron And Magnesium-Based Reactive Materials Prepared By High Energy Mechanical Milling, Xinhang Liu 2019 New Jersey Institute of Technology

Customized Boron And Magnesium-Based Reactive Materials Prepared By High Energy Mechanical Milling, Xinhang Liu

Dissertations

New reactive materials need to be developed having biocidal combustion products. When ignited, such material can add chemical biocidal effects to the common effects of high temperature and pressure. Biocidal combustion products are capable of deactivating harmful spores or bacteria, which can be released by targets containing biological weapons of mass destruction. Research showed that halogens, especially iodine, are effective as biocidal components of reactive material formulations. Recently, magnesium combustion product MgO is also found to have a biocidal effect. Thus, advanced formulations containing both magnesium and iodine are of interest; such formulations are prepared and investigated here.

Reactive materials ...


Generalized Ultrasonic Scattering Model For Arbitrary Transducer Configurations, Andrea P. Arguelles, Joseph A. Turner 2019 Pennsylvania State University

Generalized Ultrasonic Scattering Model For Arbitrary Transducer Configurations, Andrea P. Arguelles, Joseph A. Turner

Mechanical & Materials Engineering Faculty Publications

Ultrasonic scattering in polycrystalline media is directly tied to microstructural features. As a result, modeling efforts of scattering from microstructure have been abundant. The inclusion of beam modeling for the ultrasonic transducers greatly simplified the ability to perform quantitative, fully calibrated experiments. In this article, a theoretical scattering model is generalized to allow for arbitrary source and receiver configurations, while accounting for beam behavior through the total propagation path. This extension elucidates the importance and potential of out-of-plane scattering modes in the context of microstructure characterization. The scattering coefficient is explicitly written for the case of statistical isotropy and ellipsoidal ...


Highly Reactive Energetic Films By Pre-Stressing Nano-Aluminum Particles, Michael N. Bello, Alan M. Williams, Valery I. Levitas, Nobumichi Tamura, Daniel K. Unruh, Juliusz Warzywoda, Michelle L. Pantoya 2019 Texas Tech University

Highly Reactive Energetic Films By Pre-Stressing Nano-Aluminum Particles, Michael N. Bello, Alan M. Williams, Valery I. Levitas, Nobumichi Tamura, Daniel K. Unruh, Juliusz Warzywoda, Michelle L. Pantoya

Aerospace Engineering Publications

Energetic films were synthesized using stress altered nano-aluminum particles (nAl). The nAl powder was pre-stressed to examine how modified mechanical properties of the fuel particles influenced film reactivity. Pre-stressing conditions varied by quenching rate. Slow and rapid quenching rates induced elevated dilatational strain within the nAl particles that was measured using synchrotron X-ray diffraction (XRD). An analytical model for stress and strain in a nAl core–Al2O3 shell particle that includes creep in the shell and delamination at the core–shell boundary, was developed and used for interpretation of strain measurements. Results show rapid quenching induced 81% delamination at the ...


Me-Em Enewsbrief, December 2019, Department of Mechanical Engineering-Engineering Mechanics, Michigan Technological University 2019 Michigan Technological University

Me-Em Enewsbrief, December 2019, Department Of Mechanical Engineering-Engineering Mechanics, Michigan Technological University

Department of Mechanical Engineering-Engineering Mechanics eNewsBrief

No abstract provided.


A Cfd Study On The Performance Of High Speed Planing Hulls, Mowgli J. Crosby 2019 Grand Valley State University

A Cfd Study On The Performance Of High Speed Planing Hulls, Mowgli J. Crosby

Masters Theses

Most high speed water craft are able to achieve high speeds through the use of a planing hull. Planing hulls use hydrodynamic forces to lift a portion of the vessel out of the water, reducing drag, and allowing for greater speeds. Determining the flow around such vessels is traditionally achieved using a scale model in a tow tank. The purpose of this study was to analyze the performance of a high speed planing hull determine the effects of several geometric features using computational fluid dynamics rather than traditional experimentation. The goal was to determine the best configuration to ensure the ...


Optimizing Block-Stacking Operations With Relocation, Hueon Lee 2019 University of Arkansas, Fayetteville

Optimizing Block-Stacking Operations With Relocation, Hueon Lee

Theses and Dissertations

The focus of the dissertation is developing the optimization problem of finding the minimum-cost operational plan of block stacking with relocation as well as devising a solution procedure to solve practical-sized instances of the problem. Assuming changeable row depth instead of permanent row depth, this research is distinguished from conventional block stacking studies.

The first contribution of the dissertation is the development of the optimization problem under the assumption of deterministic demand. The problem is modeled using integer programming as a variation of the unsplittable multi-commodity flow problem. To find a good feasible solution of practical-sized instances in reasonable time ...


Design, Modeling And Control Of A Two-Wheel Balancing Robot Driven By Bldc Motors, Charles T. Refvem 2019 California Polytechnic State University, San Luis Obispo

Design, Modeling And Control Of A Two-Wheel Balancing Robot Driven By Bldc Motors, Charles T. Refvem

Master's Theses and Project Reports

The focus of this document is on the design, modeling, and control of a self-balancing two wheel robot, hereafter referred to as the balance bot, driven by independent brushless DC (BLDC) motors. The balance bot frame is composed of stacked layers allowing a lightweight, modular, and rigid mechanical design. The robot is actuated by a pair of brushless DC motors equipped with Hall effect sensors and encoders allowing determination of the angle and angular velocity of each wheel. Absolute orientation measurement is accomplished using a full 9-axis IMU consisting of a 3-axis gyroscope, a 3-axis accelerometer, and a 3-axis magnetometer ...


Multi-Resonant Feedback Control Of Multiple Degree-Of-Freedom Wave Energy Converters, Ossama Abdelkhalik, Shangyan Zou, Rush D. Robinett III, David G. Wilson, Giorgio Bacelli, Ryan G. Coe, Umesh Korde 2019 Michigan Technological University

Multi-Resonant Feedback Control Of Multiple Degree-Of-Freedom Wave Energy Converters, Ossama Abdelkhalik, Shangyan Zou, Rush D. Robinett Iii, David G. Wilson, Giorgio Bacelli, Ryan G. Coe, Umesh Korde

Michigan Tech Patents

Multi-resonant control of a 3 degree-of-freedom (heave-pitch-surge) wave energy converter enables energy capture that can be in the order of three times the energy capture of a heave-only wave energy converter. The invention uses a time domain feedback control strategy that is optimal based on the criteria of complex conjugate control. The multi-resonant control can also be used to shift the harvested energy from one of the coupled modes to another, enabling the elimination of one of the actuators otherwise required in a 3 degree-of-freedom wave energy converter. This feedback control strategy does not require wave prediction; it only requires ...


Effect Of Annealing On The Contact Resistance Of Aluminum On A P-Type Substrate, Shrey Shah, George Patrick Watson 2019 Singh Center for Nanotechnology

Effect Of Annealing On The Contact Resistance Of Aluminum On A P-Type Substrate, Shrey Shah, George Patrick Watson

Protocols and Reports

Aluminum contacts are widely used to form both ohmic and rectifying contacts. The process to form these contacts involves annealing, thus it is important to study the effect of annealing on the electrical properties of the contacts. Here, we present a way to measure the contact resistance of aluminum contacts formed on a p-type silicon substrate. It was found the contact resistivity decreased by an average of 18%. It was thus found that annealing at 400°C in a forming gas environment improves the electrical properties of aluminum contacts.


Development Of Mbd Model And Analysis Methodology For Vehicle Design, Alfonso Christopher Ponce 2019 University of New Mexico

Development Of Mbd Model And Analysis Methodology For Vehicle Design, Alfonso Christopher Ponce

Mechanical Engineering ETDs

This thesis is to provide a new methodology that considers the effects the chassis applies during dynamic load to the suspension and the handling characteristics of a road course vehicle. A methodology in which is described in detail as well as an applied demonstration where literature before this thesis, lacks in replication and serves to establish a basis for multi-body dynamic analysis in this area. Two models to be created, rigid and flexible, and to compare each other to study the effects the chassis torsional stiffness has during load transfer. Ultimately, to assist in the design of a vehicle that ...


Development Of Engineered Cementitious Composites With Conductive Inclusions For Use In Self-Sensing Applications, Benny Suryanto Dr, Danah Saraireh Ms, Steven Walls Mr, Jaehwan Kim Dr, W John McCarter Prof 2019 Heriot-Watt University

Development Of Engineered Cementitious Composites With Conductive Inclusions For Use In Self-Sensing Applications, Benny Suryanto Dr, Danah Saraireh Ms, Steven Walls Mr, Jaehwan Kim Dr, W John Mccarter Prof

International Conference on Durability of Concrete Structures

The mechanical and a.c. electrical properties of a new varietal of engineered cementitious composite (ECC) incorporating conductive inclusions are presented. Electrical measurements were undertaken over a wide frequency range while curing and when under uniaxial tensile loading to study the influence of ongoing hydration and multiple microcrack formation on the composite electrical impedance. When presented in Nyquist format, the work shows that conductive inclusions reduce the bulk resistance of the composite while enhancing its polarizability, transforming the classic, single-arc bulk response of typical cement-based materials to a two-arc response. The bulk resistance was shown to increase with time and ...


Load-Bearing Capacity Of Corroded Reinforced Concrete Structures Caused By Carbonation And Exposed To Xc4, Esko Sistonen 2019 Purdue University

Load-Bearing Capacity Of Corroded Reinforced Concrete Structures Caused By Carbonation And Exposed To Xc4, Esko Sistonen

International Conference on Durability of Concrete Structures

Concrete corrosion can be visualized as a combination of chemical reaction on concrete and electrochemical reaction on steel reinforcement. Failure of steel reinforcement due to corrosion can inflict significant stress on concrete during load distribution. As such, it is necessary to analyse the long-term effects of corrosion on the load bearing capacity and bending strength of steel reinforcement. This research investigated the mechanical and electrochemical properties of concrete exposed to long-term corrosion for a period of 16 years. Non-destructive testing like crack width measurements, visual examination, electrochemical measurements using Galva Pulse and determination of average chloride content were undertaken to ...


Experimental And Numerical Investigation On The Irregularity Of Carbonation Depth Of Concrete Under Supercritical Condition, Hao Bao Masc, Min Yu Dr., Jianqiao Ye Dr., Lihua Xu Dr., Yin Chi Dr., J Ye 2019 Wuhan University

Experimental And Numerical Investigation On The Irregularity Of Carbonation Depth Of Concrete Under Supercritical Condition, Hao Bao Masc, Min Yu Dr., Jianqiao Ye Dr., Lihua Xu Dr., Yin Chi Dr., J Ye

International Conference on Durability of Concrete Structures

The heterogeneity of a cement-based material results in a random spatial distribution of carbonation depth, which may significantly affect the mechanical properties and durability of the material. Currently, there is a lack of both experimental and numerical investigations aiming at a statistical understanding of this important phenomenon. This paper presents both experimental and numerical supercritical carbonation test results of concrete blocks. The random fields of porosity and two-dimension random aggregate model of concrete were proposed for the simulation. The carbonation depths are measured and distributed along the carbonation boundary by the proposed rapid image processing technique, which are then statistically ...


Alkali Reactive Carbonate Rocks: Is It Alkali Silica Reaction (Asr) Or Alkali Carbonate Reaction (Acr)?, Mengesha Beyene, RC Meininger 2019 SES Group & Associates, LLC

Alkali Reactive Carbonate Rocks: Is It Alkali Silica Reaction (Asr) Or Alkali Carbonate Reaction (Acr)?, Mengesha Beyene, Rc Meininger

International Conference on Durability of Concrete Structures

The root cause of distress in two different concrete structures made from carbonate coarse aggregates that fit the textural and compositional criteria cited for ACR was found to be caused by ASR, not ACR. Stereo-optical examination and transmitted polarized light microscopy (PLM) analysis showed that the concretes contain some dark gray, fine-grained argillaceous dolomitic coarse aggregates in which secondary white deposit filling the cracks extending from these aggregates into the paste (as well as lining air voids) is ASR gel. Back scattered electron (BSE) imaging with EDS spectra and x-ray elemental mappings, clearly confirm that the white secondary deposits consist ...


Factors Influencing Retirement Decision Making For Louisiana State Government Employees, Osama A. Amous 2019 Louisiana State University

Factors Influencing Retirement Decision Making For Louisiana State Government Employees, Osama A. Amous

LSU Doctoral Dissertations

ABSTRACT

Public pension members continually face factors affecting their decision to retire in the changing American society. Workers are living longer and need more medical care with better retirement benefits. For Louisiana public employees specifically, no prior studies have examined the factors affecting workers’ decision to retire nor evaluated the factors impacting workers’ decision.

This multiphase study aimed to identify factors and evaluate the decision-making process that enables Louisianans to retire happily and satisfied with a guaranteed income, and to examine millennials’ decision-making process. In the initial phase, ten active and retired male and female participants answered questions in-person, leading ...


Beyond The Toolpath: Site-Specific Melt Pool Size Control Enables Printing Of Extra-Toolpath Geometry In Laserwire-Based Directed Energy Deposition, Brian T. Gibson, Bradley S. Richardson, Tayler W. Undermann, Lonnie J. Love 2019 Oak Ridge National Laboratory

Beyond The Toolpath: Site-Specific Melt Pool Size Control Enables Printing Of Extra-Toolpath Geometry In Laserwire-Based Directed Energy Deposition, Brian T. Gibson, Bradley S. Richardson, Tayler W. Undermann, Lonnie J. Love

Mechanical & Materials Engineering Faculty Publications

A variety of techniques have been utilized in metal additive manufacturing (AM) for melt pool size management, including modeling and feed-forward approaches. In a few cases, closed-loop control has been demonstrated. In this research, closed-loop melt pool size control for large-scale, laser wire-based directed energy deposition is demonstrated with a novel modification, i.e., site-specific changes to the controller setpoint were commanded at trigger points, the locations of which were generated by the projection of a secondary geometry onto the primary three-dimensional (3D) printed component geometry. The present work shows that, through this technique, it is possible to print a ...


Influence Of Flow Rate, Nozzle Speed, Pitch And The Number Of Passes On The Thickness Of S1805 Photoresist In Suss Microtec As8 Spray Coater, Rohan Sanghvi, Gyuseok Kim 2019 Singh Center for Nanotechnology

Influence Of Flow Rate, Nozzle Speed, Pitch And The Number Of Passes On The Thickness Of S1805 Photoresist In Suss Microtec As8 Spray Coater, Rohan Sanghvi, Gyuseok Kim

Tool Data

S1805 positive photoresist has been deposited on single crystalline Si wafers using a Suss MicroTec Alta Spray. The in?uence of ?ow rate, nozzle speed, pitch and number of passes on the thickness of the photoresist was studied. Results show that the thickness of S1805 is linearly proportional to the ?ow rate and number of passes, and inversely proportional to the nozzle speed and pitch.


Effect Of Silica Fume In Concrete On Mechanical Properties And Dynamic Behaviors Under Impact Loading, Shijun Zhao, Qing Zhang 2019 Hohai University & University of Nebraska-Lincoln

Effect Of Silica Fume In Concrete On Mechanical Properties And Dynamic Behaviors Under Impact Loading, Shijun Zhao, Qing Zhang

Mechanical & Materials Engineering Faculty Publications

The effect of silica fume (SF) in concrete on mechanical properties and dynamic behaviors was experimentally studied by split Hopkinson pressure bar (SHPB) device with pulse shaping technique. Three series of concrete with 0, 12%, and 16% SF as a cement replacement by weight were produced firstly. Then the experimental procedure for dynamic tests of concrete specimens with SF under a high loading rate was presented. Considering the mechanical performance and behaviors of the concrete mixtures, those tests were conducted under five different impact velocities. The experimental results clearly show concrete with different levels of SF is a strain-rate sensitive ...


Correction Of Pattern Size Deviations In The Fabrication Of Photomasks Made With A Laser Direct-Writer, Ningzhi Xie, George Patrick Watson 2019 Singh Center for Nanotechnology

Correction Of Pattern Size Deviations In The Fabrication Of Photomasks Made With A Laser Direct-Writer, Ningzhi Xie, George Patrick Watson

Protocols and Reports

When using Heidelberg DWL66+ laser writer to fabricate the photomask, the pattern feature dimensions may have deviations. These deviations can be caused by the lithography process and the undercut in the metal etch process. The same deviation value of 0.8μm was found to appear in all the patterns independent of the pattern original size and local pattern density. To overcome this universal deviation, a universal bias is suggested to be applied to the original patterns during the data preparation for the lithography process. In order to ensure this pre-exposure bias method can work, both the laser direct-write exposure conditions ...


Stimulating Higher Order Thinking In Mechatronics By Comparing Pid And Fuzzy Control, Christopher J. Lowrance, John R. Rogers 2019 United States Military Academy

Stimulating Higher Order Thinking In Mechatronics By Comparing Pid And Fuzzy Control, Christopher J. Lowrance, John R. Rogers

West Point Research Papers

Many studies have found active learning, either in the form of in-class exercises or projects, to be superior to traditional lectures. However, these forms of hands-on learning do not always get students to reach the higher order thinking skills associated with the highest levels of Bloom’s Taxonomy (i.e., analysis, synthesis, and evaluation). Assignments that expect students to take an expected approach to reach a well-defined solution contribute to a lack of higher order thinking at the college level. Professional engineers often face complex and ambiguous problems that require design decisions, where there is no straightforward answer. To strengthen ...


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