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Full-Text Articles in Mechanical Engineering
Impact Of Surface And Pore Characteristics On Fatigue Life Of Laser Powder Bed Fusion Ti–6al–4v Alloy Described By Neural Network Models, Seunghyun Moon, Ruimin Ma, Ross Attardo, Charles Tomonto, Mark Nordin, Paul Wheelock, Michael Glavicic, Maxwell Layman, Richard Billo, Tengfei Luo
Impact Of Surface And Pore Characteristics On Fatigue Life Of Laser Powder Bed Fusion Ti–6al–4v Alloy Described By Neural Network Models, Seunghyun Moon, Ruimin Ma, Ross Attardo, Charles Tomonto, Mark Nordin, Paul Wheelock, Michael Glavicic, Maxwell Layman, Richard Billo, Tengfei Luo
Mechanical and Aerospace Engineering Faculty Research & Creative Works
In this study, the effects of surface roughness and pore characteristics on fatigue lives of laser powder bed fusion (LPBF) Ti–6Al–4V parts were investigated. The 197 fatigue bars were printed using the same laser power but with varied scanning speeds. These actions led to variations in the geometries of microscale pores, and such variations were characterized using micro-computed tomography. To generate differences in surface roughness in fatigue bars, half of the samples were grit-blasted and the other half were machined. Fatigue behaviors were analyzed with respect to surface roughness and statistics of the pores. For the grit-blasted samples, the contour …
Coalescence Characteristics Of Bulk Nanobubbles In Water: A Molecular Dynamics Study Coupled With Theoretical Analysis, Eric Bird, Eric Smith, Zhi Liang
Coalescence Characteristics Of Bulk Nanobubbles In Water: A Molecular Dynamics Study Coupled With Theoretical Analysis, Eric Bird, Eric Smith, Zhi Liang
Mechanical and Aerospace Engineering Faculty Research & Creative Works
The Coalescence of Two Nanobubbles (NBs) in Water is a Process of Great Importance to Many Industrial Applications. in This Work, We Study the Coalescence of Two Equal-Sized Nitrogen NBs in Water using Molecular Dynamics (MD) Simulations and Continuum-Based Theoretical Analysis. We Vary the NB Diameter from 30 to 50 Nm and Study the Coalescence Characteristics Including the Expansion Speed of the Capillary Bridge between Two Coalescing NBs, the Dynamic Regime of NB Coalescence, the Diameter of Fully Merged NBs, and the Temperature Variation of NBs during the Coalescence Process. for All Cases, We Show the MD Simulation Results Can …
On The Applicability Of Continuum Scale Models For Ultrafast Nanoscale Liquid-Vapor Phase Change, Anirban Chandra, Zhi Liang, Assad A. Oberai, Onkar Sahni, Pawel Keblinski
On The Applicability Of Continuum Scale Models For Ultrafast Nanoscale Liquid-Vapor Phase Change, Anirban Chandra, Zhi Liang, Assad A. Oberai, Onkar Sahni, Pawel Keblinski
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Continuum Methods Are Efficient in Modeling Multi-Phase Flow at Large Time and Length Scales, However, their Applicability to Nanoscale Systems and Processes is Questionable. When Mean Free Path and Average Time between Atomic Collisions Are Comparable to the Characteristic Length and Time Scales of Interest, the Continuum Hypothesis Approaches its Spatial and Temporal Limit. Here We Discuss the Implications of Modeling Such a Limiting Problem Involving Liquid-Vapor Phase Change using Continuum Equations of Mass, Momentum, and Energy Conservation. Our Results Indicate that, Continuum Conservation Laws Can Correctly Represent the Dynamics of the Specific Problem of Interest Provided Appropriate Constitutive Relations …
Simulation And Modeling Of Hypersonic Turbulent Boundary Layers Subject To Adverse Pressure Gradients Due To Concave Streamline Curvature, Gary L. Nicholson, Junji Huang, Lian Duan, Meelan M. Choudhari
Simulation And Modeling Of Hypersonic Turbulent Boundary Layers Subject To Adverse Pressure Gradients Due To Concave Streamline Curvature, Gary L. Nicholson, Junji Huang, Lian Duan, Meelan M. Choudhari
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Direct numerical simulations (DNS) of adverse-pressure-gradient turbulent boundary layers over a planar concave wall are presented for a nominal freestream Mach number of 5, with the objective of assessing the limitations of the currently available Reynolds-averaged Navier-Stokes (RANS) models. The wall geometry and flow conditions of the DNS are representative of the experimental data for a Mach 4.9 turbulent boundary layer that was tested on a two-dimensional planar concave wall model in the high-speed blow-down wind tunnel located at the National Aerothermochemistry Laboratory at Texas A&M University (TAMU). The DNS was validated against the experimental results of TAMU for the …
Theoretical Study Of Magnetic Particles In A Shear Flow Subjected To A Uniform Magnetic Field, Christopher A. Sobecki
Theoretical Study Of Magnetic Particles In A Shear Flow Subjected To A Uniform Magnetic Field, Christopher A. Sobecki
Doctoral Dissertations
"Magnetic manipulation of non-spherical magnetic microparticles is important for applications in shape-based and magnetic-based separations such as waste management, disease diagnostics, drug delivery, and mining. Manipulations of magnetic microparticles also include chain formation to assemble compositions for electronics, drug loading designs, and magnetorheological fluids for smart armor, hydraulic brakes, and dampers. In microfluidic devices, separation-formation-effectiveness depends on the shape of the channel, the shear rate, and the magnetic field strength and direction.
Particle separation and chain formation involved highly complex and computational expense-demanding studies in microfluidic devices, magnetic fields, and particle- particle/wall interactions. This research took complex experimental studies and …
Dynamic Behavior And Interactions Of Ferrofluid Droplets Under Magnetic Fields In Low Reynolds Number Flows, Md Rifat Hassan
Dynamic Behavior And Interactions Of Ferrofluid Droplets Under Magnetic Fields In Low Reynolds Number Flows, Md Rifat Hassan
Doctoral Dissertations
Digital microfluidics in combination with emulsion microfluidics are crucial building blocks of droplet-based microfluidics, which are prevalent in a wide variety of industrial and biomedical applications, including polymer processing, food production, drug delivery, inkjet printing, and cell-based assays. Therefore, understanding the dynamics and interactions of droplets as well as the interactions between the droplets and solid surfaces are of great importance in order to improve the performance or product in these applications.
Recently, several studies in the literature have demonstrated the potential of magnetic fields in controlling the behavior of droplets in microscale; however, the fundamental mechanism behind the interesting …
Novel Piezo Actuators For Surface Cleaning, Yezad H. Anklesaria
Novel Piezo Actuators For Surface Cleaning, Yezad H. Anklesaria
Doctoral Dissertations
"Optical cameras are becoming increasingly common and are used in a variety of applications. With recent progress and transition toward more autonomous systems, the usage of optical systems will be common and widespread. Applications of the optical systems range from autonomous vehicles, home security systems, aviation, extraterrestrial vehicles, spacecraft, and satellites. Imaging systems are used in decision-making in many of these applications. Fouling of the field of view of the imaging system can impede the decision process. An active autonomous cleaning method for the optical surface of the optical systems reliably would be advantageous. The research work focuses on developing …