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Mechanical and Aerospace Engineering Faculty Research & Creative Works

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Full-Text Articles in Engineering

Oxidation Polymerization Additive Manufacturing, Jonghyun Park, Tazdik Patwary Plateau, Hiep Pham Apr 2021

Oxidation Polymerization Additive Manufacturing, Jonghyun Park, Tazdik Patwary Plateau, Hiep Pham

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Various processes for producing three dimensional electrically conductive polymer structures, such as three dimensional structures of poly(3,4-ethylenedioxythiophene), are described as well as materials produced by these processes.


Experimental And Numerical Investigation In Directed Energy Deposition For Component Repair, Lan Li, Xinchang Zhang, Frank W. Liou Mar 2021

Experimental And Numerical Investigation In Directed Energy Deposition For Component Repair, Lan Li, Xinchang Zhang, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Directed energy deposition (DED) has been widely used for component repair. In the repair process, the surface defects are machined to a groove or slot and then refilled. The sidewall inclination angle of the groove geometry has been recognized to have a considerable impact on the mechanical properties of repaired parts. The objective of this work was to investigate the feasibility of repairing various V-shaped defects with both experiments and modeling. At first, the repair volume was defined by scanning the defective zone. Then, the repair volume was sliced to generate the repair toolpath. After that, the DED process was …


Time-Dependent System Reliability Analysis With Second-Order Reliability Method, Hao Wu, Zhangli Hu, Xiaoping Du Mar 2021

Time-Dependent System Reliability Analysis With Second-Order Reliability Method, Hao Wu, Zhangli Hu, Xiaoping Du

Mechanical and Aerospace Engineering Faculty Research & Creative Works

System reliability is quantified by the probability that a system performs its intended function in a period of time without failures. System reliability can be predicted if all the limit-state functions of the components of the system are available, and such a prediction is usually time consuming. This work develops a time-dependent system reliability method that is extended from the component time-dependent reliability method using the envelope method and second-order reliability method. The proposed method is efficient and is intended for series systems with limit-state functions whose input variables include random variables and time. The component reliability is estimated by …


Adaptive Kriging Method For Uncertainty Quantification Of The Photoelectron Sheath And Dust Levitation On The Lunar Surface, Xinpeng Wei, Jianxun Zhao, Xiaoming He, Zhen Hu, Xiaoping Du, Daoru Han Mar 2021

Adaptive Kriging Method For Uncertainty Quantification Of The Photoelectron Sheath And Dust Levitation On The Lunar Surface, Xinpeng Wei, Jianxun Zhao, Xiaoming He, Zhen Hu, Xiaoping Du, Daoru Han

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This paper presents an adaptive Kriging based method to perform uncertainty quantification (UQ) of the photoelectron sheath and dust levitation on the lunar surface. The objective of this study is to identify the upper and lower bounds of the electric potential and that of dust levitation height, given the intervals of model parameters in the one-dimensional (1D) photoelectron sheath model. To improve the calculation efficiency, we employ the widely used adaptive Kriging method (AKM). A task-oriented learning function and a stopping criterion are developed to train the Kriging model and customize the AKM. Experiment analysis shows that the proposed AKM …


Fuel Cell Having Corrugated Membrane Electrode Assembly, Jonghyun Park Feb 2021

Fuel Cell Having Corrugated Membrane Electrode Assembly, Jonghyun Park

Mechanical and Aerospace Engineering Faculty Research & Creative Works

An electrochemical reaction cell comprising an anode electrode, a cathode electrode, and a membrane electrode assembly (MEA). The MEA is positioned between the anode electrode and the cathode electrode. The anode electrode, the cathode electrode, and the MEA each have a corrugated shape and are contained within a recess of a housing.


Non-Prehensile Manipulation Of A Devil-Stick: Planar Symmetric Juggling Using Impulsive Forces, Nilay Kant, Ranjan Mukherjee Feb 2021

Non-Prehensile Manipulation Of A Devil-Stick: Planar Symmetric Juggling Using Impulsive Forces, Nilay Kant, Ranjan Mukherjee

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Juggling a devil-stick can be described as a problem of non-prehensile manipulation. Assuming that the devil-stick remains confined to the vertical plane, the problem of juggling the stick between two symmetric configurations is considered. Impulsive forces are applied to the stick intermittently and the impulse of the force and its point of application are modeled as control inputs to the system. The dynamics of the devil-stick due to the impulsive forces and gravity is described by half-return maps between two Poincaré sections; the symmetric configurations are fixed points of these sections. A coordinate transformation is used to convert the juggling …


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 Feb 2021

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 …


Dynamics Of A Pair Of Paramagnetic Janus Particles Under A Uniform Magnetic Field And Simple Shear Flow, Christopher Sobecki, Jie Zhang, Cheng Wang Jan 2021

Dynamics Of A Pair Of Paramagnetic Janus Particles Under A Uniform Magnetic Field And Simple Shear Flow, Christopher Sobecki, Jie Zhang, Cheng Wang

Mechanical and Aerospace Engineering Faculty Research & Creative Works

We numerically investigate the dynamics of a pair of circular Janus microparticles immersed in a Newtonian fluid under a simple shear flow and a uniform magnetic field by direct numerical simulation. Using the COMSOL software, we applied the finite element method, based on an arbitrary Lagrangian-Eulerian approach, and analyzed the dynamics of two anisotropic particles (i.e., one-half is paramagnetic, and the other is non-magnetic) due to the center-to-center distance, magnetic field strength, initial particle orientation, and configuration. This article considers two configurations: the LR-configuration (magnetic material is on the left side of the first particle and on the right side …


Aerothermal Uncertainty Quantification Of Deployable Entry Technologies Using Multi-Fidelity Modeling, Mario Santos, Serhat Hosder, Thomas K. West Jan 2021

Aerothermal Uncertainty Quantification Of Deployable Entry Technologies Using Multi-Fidelity Modeling, Mario Santos, Serhat Hosder, Thomas K. West

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The objective of this work was to investigate the use of a co-Kriging based multi-fidelity modeling approach with a Monte Carlo uncertainty quantification analyses of surface heating on hypersonic inflatable aerodynamic decelerator vehicles and adaptable, deployable entry placement technology vehicles in Mars entry. A previously developed co-Kriging based multi-fidelity modeling approach was used to model the laminar and turbulent convective and radiative heat fluxes along the vehicle. Monte Carlo analyses of surface heat load for nine different vehicle nose radii was performed for both vehicles, assuming the same thermal protection system is used for both vehicles. The maximum heat loads …


Efficient Solution Of Surface Erosion In Particle-Laden Hypersonic Flows, Andrew Hinkle, Serhat Hosder, Christopher Johnston Jan 2021

Efficient Solution Of Surface Erosion In Particle-Laden Hypersonic Flows, Andrew Hinkle, Serhat Hosder, Christopher Johnston

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The standard approach for simulating hypersonic dust erosion problems using mixed Eulerian-Lagrangian two-phase solvers is too computationally expensive for routine simulations, and particularly for uncertainty quantification (UQ) analyses. To enable these analyses, a new approach for solving this problem with a sparse set of particles is presented and demonstrated on a problem from literature involving the ExoMars Schiaparelli entry vehicle. This new approach, referred to here as the Trajectory Control Volume (TCV) method is verified against traditional approaches based on Monte Carlo, and is shown to require over 3 orders-of-magnitude less samples to obtain the same results. An example UQ …


Enthesis Strength, Toughness And Stiffness: An Image-Based Model Comparing Tendon Insertions With Varying Bony Attachment Geometries, Mikhail Golman, Victor Birman, Stavros Thomopoulos, Guy M. Genin Jan 2021

Enthesis Strength, Toughness And Stiffness: An Image-Based Model Comparing Tendon Insertions With Varying Bony Attachment Geometries, Mikhail Golman, Victor Birman, Stavros Thomopoulos, Guy M. Genin

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Tendons of the body differ dramatically in their function, mechanics and range of motion, but all connect to bone via an enthesis. Effective force transfer at the enthesis enables joint stability and mobility, with strength and stiffness arising from a fibrous architecture. However, how enthesis toughness arises across tendons with diverse loading orientations remains unclear. To study this, we performed simultaneous imaging of the bone and tendon in entheses that represent the range of tendon-to-bone insertions and extended a mathematical model to account for variations in insertion and bone geometry. We tested the hypothesis that toughness, across a range of …


Modeling Rack Force For Steering Maneuvers In A Stationary Vehicle, Nilay Kant, Raunav Chitkara, Prerit Pramod Jan 2021

Modeling Rack Force For Steering Maneuvers In A Stationary Vehicle, Nilay Kant, Raunav Chitkara, Prerit Pramod

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A steering system converts circular motion of the steering wheel into yaw motion of the road-wheels. In absence of a steering assist mechanism, the driver torque overcomes the tire-road friction forces, which is transmitted to the steering rack through tie rods attached to the road-wheels. The net force acting on the rack is then transmitted to the steering wheel through mechanical linkages which results in natural haptic feedback, commonly referred to as the steering feel. In an electric/hydraulic power steering, an electro-mechanical actuator applies assist force, which reduces the torque required by the driver. In order to maintain stability of …


Novel Adaptive Sampling Algorithm For Pod-Based Non-Intrusive Reduced Order Model, Jiachen Wang, Xiaosong Du, Joaquim R.R.A. Martins Jan 2021

Novel Adaptive Sampling Algorithm For Pod-Based Non-Intrusive Reduced Order Model, Jiachen Wang, Xiaosong Du, Joaquim R.R.A. Martins

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The proper orthogonal decomposition (POD) based reduced-order model (ROM) has been an effective tool for flow field prediction in the engineering industry. The sample selection in the design space for POD basis construction affects the ROM performance sensitively. Adaptive sampling can significantly reduce the number of samples to achieve the required model accuracy. In this work, we propose a novel adaptive sampling algorithm, called conjunction sampling strategy, which is based on proven strategies. The conjunction sampling strategy is demonstrated on airfoil flow field prediction within the transonic regime. We demonstrate the performance of the proposed strategy by running 10 trials …


A Convolutional Neural Network Model Based On Multiscale Structural Similarity For The Prediction Of Flow Fields, Yifu An, Xiaosong Du, Joaquim R.R.A. Martins Jan 2021

A Convolutional Neural Network Model Based On Multiscale Structural Similarity For The Prediction Of Flow Fields, Yifu An, Xiaosong Du, Joaquim R.R.A. Martins

Mechanical and Aerospace Engineering Faculty Research & Creative Works

We have seen the emerging applications of deep neural networks for flow field predictions in the past few years. Most of the efforts rely on the increased complexity of the model itself or take advantage of novel network architectures, such as convolutional neural networks (CNN). However, reaching low prediction error cannot guarantee the quality of the predicted flow fields in terms of the perceived visual quality. This work introduces the multi-scale structural similarity (MS-SSIM) index method for flow field prediction. First, we train CNN models using the commonly used root mean squared error (RMSE) loss function as the reference. Then …


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 Jan 2021

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 …


Effect Of Nonlinear Mixing On Electrospray Propulsion Predictions, Mitchell J. Wainwright, Joshua L. Rovey Jan 2021

Effect Of Nonlinear Mixing On Electrospray Propulsion Predictions, Mitchell J. Wainwright, Joshua L. Rovey

Mechanical and Aerospace Engineering Faculty Research & Creative Works

No abstract provided.


The Effect Of Laser Welding Modes On Mechanical Properties And Microstructure Of 304l Stainless Steel Parts Fabricated By Laser-Foil-Printing Additive Manufacturing, Chia Hung Hung, Wei Ting Chen, M. Hossein Sehhat, Ming C. Leu Jan 2021

The Effect Of Laser Welding Modes On Mechanical Properties And Microstructure Of 304l Stainless Steel Parts Fabricated By Laser-Foil-Printing Additive Manufacturing, Chia Hung Hung, Wei Ting Chen, M. Hossein Sehhat, Ming C. Leu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The success of laser-foil-printing (LFP) additive manufacturing depends critically on the laser welding of sheet metals onto the substrate or the previous layer during the part fabrication process. The welding can be generally categorized into two modes: conduction mode and keyhole mode. In this study, 304L stainless steel parts fabricated by the LFP process using the two laser welding modes are compared. The porosity, microstructure, and tensile properties of the fabricated parts in these two modes are measured and compared in the laser scanning direction (X) and part building direction (Z). The parts fabricated in the conduction mode have a …


In-Plane Anisotropic Third-Harmonic Generation From Germanium Arsenide Thin Flakes, Huseyin Sar, Jie Gao, Xiaodong Yang Dec 2020

In-Plane Anisotropic Third-Harmonic Generation From Germanium Arsenide Thin Flakes, Huseyin Sar, Jie Gao, Xiaodong Yang

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A newly introduced two-dimensional (2D) layered germanium arsenide (GeAs) has attracted growing interest due to its promising highly in-plane anisotropic crystal structure and electronic properties for photonic and optoelectronic applications. The potential of 2D layered GeAs for many applications such as anisotropic photodetection, electronics, superconductivity and thermoelectricity is being investigated in recent studies. However, the intrinsic nonlinear optical properties of 2D layered GeAs have not been explored yet. Here, thickness- and incident polarization-dependent in-plane anisotropic third-harmonic generation (THG) from the mechanically exfoliated thin GeAs flakes is reported. Furthermore, the effect of the flake thickness on the THG conversion efficiency is …


Modular Framework For Implementation And Analysis Of Recursive Filters With Considered And Neglected Parameters, Kyle J. Demars, Kari C. Ward Dec 2020

Modular Framework For Implementation And Analysis Of Recursive Filters With Considered And Neglected Parameters, Kyle J. Demars, Kari C. Ward

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This paper develops novel covariance and square-root factor formulations of a consider-neglect Kalman filter for navigation applications. The proposed filter partitions system parameters into three distinct categories: those to be estimated by the filter, those whose contribution to the system are considered without being explicitly estimated, and those with sufficiently low effect on the system such that their contribution can be neglected altogether. Discussion on appropriate selection of parameters to be considered and neglected is provided with specific attention given to descent-to-landing navigation. Monte Carlo simulations and analysis are performed to assess the performance of the developed square-root consider-neglect filter …


Laser-Based Interfacial Patterning Enables Toughening Of Cfrp/Epoxy Joints Through Bridging Of Adhesive Ligaments, Ran Tao, Xiaole Li, Arief Yudhanto, Marco Alfano, Gilles Lubineau Dec 2020

Laser-Based Interfacial Patterning Enables Toughening Of Cfrp/Epoxy Joints Through Bridging Of Adhesive Ligaments, Ran Tao, Xiaole Li, Arief Yudhanto, Marco Alfano, Gilles Lubineau

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The ability to prevent catastrophic failures in secondary bonded CFRP adhesive joints is important for reliable automotive and aerospace structures. In a previous study, we proposed an innovative damage-tolerant interfacial design concept for adhesively bonded composite joints, which relied on the extrinsic dissipation of bridging adhesive ligaments enabled by controlling the adhesion at CFRP/epoxy interfaces. In this work, we experimentally validate this strategy by combining laser processing and mechanical testing using double cantilever beam (DCB) joints. Mechanical tests indicate that the pattern geometry, i.e., number and spacing of the areas with different adhesion, controls the formation of either single or …


Additive Manufacturing-Enabled Design, Manufacturing, And Lifecycle Performance, Tao Peng, Yi Zhu, Ming Leu, David Bourell Dec 2020

Additive Manufacturing-Enabled Design, Manufacturing, And Lifecycle Performance, Tao Peng, Yi Zhu, Ming Leu, David Bourell

Mechanical and Aerospace Engineering Faculty Research & Creative Works

No abstract provided.


Vibration Analysis Of Simultaneous Drilling And Reaming Bha, Mohammed F. Al Dushaishi, Daniel S. Stutts Dec 2020

Vibration Analysis Of Simultaneous Drilling And Reaming Bha, Mohammed F. Al Dushaishi, Daniel S. Stutts

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The drillstring used in the oil and gas exploration is a complex structure due to the different forces acting on it. One of the primary sources of drillstring vibrations is the cutting forces caused by the drill bit contact with the rock formation. In some drilling applications, such as hole enlargement and underreaming, the source of the cutting action originates from the drill bit as well as the reamer which increases the dynamic complexity of the drillstring. This paper’s objective is to investigate the torsional vibration behaviors of the bottom hole assembly (BHA) under simultaneous drilling and reaming. More specifically, …


Coalescence Speed Of Two Equal-Sized Nanobubbles, Eric Bird, Jun Zhou, Zhi Liang Dec 2020

Coalescence Speed Of Two Equal-Sized Nanobubbles, Eric Bird, Jun Zhou, Zhi Liang

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In This Work, We Use Molecular Dynamics (MD) Simulations Coupled with Continuum-Based Theoretical Analysis to Study the Coalescence Dynamics of Two Equal-Sized Nanobubbles (NBs). We First Derive a Governing Equation for the Evolution of the Capillary Bridge Radius between Two Coalescing NBs from the Axisymmetric Navier-Stokes Equation. to Verify the Prediction from the Governing Equation, We Carry Out MD Simulations of the Coalescence of Two NBs in a Lennard-Jones Fluid System and Directly Measure the Bridge Radius, Rb, as a Function of Time, T. by Varying the Bubble Diameter, We Change the NB Ohnesorge Number from 0.46 to 0.33. in …


Explosive Compaction Of Additively Manufactured Material, Phillip R. Mulligan, Cody Lough, Douglas A. Bristow, Edward Kinzel, Catherine E. Johnson Nov 2020

Explosive Compaction Of Additively Manufactured Material, Phillip R. Mulligan, Cody Lough, Douglas A. Bristow, Edward Kinzel, Catherine E. Johnson

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Selective Laser Melting (SLM) is an additive manufacturing (AM) technique that uses a laser to locally fuse material in a metal-powder bed. The process is performed in layers enabling significant geometric freedom over traditional manufacturing techniques. During the deposition process, the metal is locally melted and rapidly self-quenched, leading to rapid solidification with well-defined melt-pool boundaries. Analogies are often drawn to the microstructure created in welding, albeit extending to the entire part. The SLM process parameters are optimized to produce near full density metal parts. The process parameters can also be adjusted to produce local regions that are of unmelted …


Direct 3d Printing Of Silica Doped Transparent Magnesium Aluminate Spinel Ceramics, John M. Pappas, Xiangyang Dong Nov 2020

Direct 3d Printing Of Silica Doped Transparent Magnesium Aluminate Spinel Ceramics, John M. Pappas, Xiangyang Dong

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Transparent magnesium aluminate spinel ceramics were additively manufactured via a laser direct deposition method in this study. With a minimum porosity of 0.3% achieved, highly transparent spinel samples with the highest total optical transmittance of 82% at a wavelength of 632.8 nm, were obtained by a 3D printing approach. However, cracking was found to be a major issue affecting printed spinel samples. To control prevalent cracking, the effect of silica dopants was investigated. Increased silica dopants reduced average total crack length by up to 79% and average crack density by up to 71%. However, a high dopant level limited optical …


Efficient Yield Estimation Of Multiband Patch Antennas By Polynomial Chaos-Based Kriging, Leifur Leifsson, Xiaosong Du, Slawomir Koziel Nov 2020

Efficient Yield Estimation Of Multiband Patch Antennas By Polynomial Chaos-Based Kriging, Leifur Leifsson, Xiaosong Du, Slawomir Koziel

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Yield estimation of antenna systems is important to check their robustness with respect to the uncertain sources. Since direct Monte Carlo sampling of accurate physics-based models can be computationally intensive, this work proposes the use of the polynomial chaos–Kriging (PC-Kriging) metamodeling method for fast yield estimation of multiband patch antennas. PC-Kriging integrates the polynomial chaos expansion (PCE) as the trend function of Kriging metamodel since the PCE is good at capturing the function tendency and Kriging is good at matching the observations at training points. The PC-Kriging method is demonstrated on two analytical cases and two multiband patch antenna cases …


Enhancement Of Fracture Toughness In Secondary Bonded Cfrp Using Hybrid Thermoplastic/Thermoset Bondline Architecture, A. Yudhanto, M. Almulhim, F. Kamal, R. Tao, L. Fatta, M. Alfano, G. Lubineau Oct 2020

Enhancement Of Fracture Toughness In Secondary Bonded Cfrp Using Hybrid Thermoplastic/Thermoset Bondline Architecture, A. Yudhanto, M. Almulhim, F. Kamal, R. Tao, L. Fatta, M. Alfano, G. Lubineau

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Structures made of carbon fiber-reinforced polymer (CFRP) can be assembled using adhesive bonding. However, such bonding is prone to brittle delamination, and a method to improve delamination resistance is desirable. Here, we propose a technique to introduce crack-arrest features that increase the R-curve response by engineering the adhesive bond line/interface. We specifically designed a wavy net-like thermoplastic insert that was embedded into the thermoset adhesive bond line where the new mechanisms of energy dissipation were generated. We demonstrate that the technique is effective at improving mode I fracture toughness of secondary bonded carbon/epoxy by more than 400%. The hybrid thermoset/thermoplastic …


Maximum Evaporating Flux Of Molecular Fluids From A Planar Liquid Surface, Eric Bird, Zhi Liang Oct 2020

Maximum Evaporating Flux Of Molecular Fluids From A Planar Liquid Surface, Eric Bird, Zhi Liang

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In This Work, We Use the Kinetic Theory of Gases (KTG) to Develop a Theoretical Model to Understand the Role of Internal Motions of Molecules on the Maximum Evaporation Flux from a Planar Liquid Surface. the Kinetic Theory is Applied to Study the Evaporation of Molecular Fluids into a Vacuum and Predict the Dimensionless Maximum Evaporation Flux (JR,max, I.e., the Ratio of the Maximum Evaporation Flux to the Molar Flux Emitted from a Liquid Surface). the Key Assumptions Regarding the Velocity Distribution Function (VDF) of Polyatomic Molecules in the Highly Nonequilibrium Vapor Near the Evaporating Surface Are Validated by the …


Review Of Multimode Space Propulsion, Joshua L. Rovey, Christopher T. Lyne, Alex J. Mundahl, Nicolas Rasmont, Matthew S. Glascock, Mitchell J. Wainwright, Steven P. Berg Oct 2020

Review Of Multimode Space Propulsion, Joshua L. Rovey, Christopher T. Lyne, Alex J. Mundahl, Nicolas Rasmont, Matthew S. Glascock, Mitchell J. Wainwright, Steven P. Berg

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Multimode propulsion is the integration of two or more propulsive modes with shared propellant into a single spacecraft propulsion system. Multimode propulsion is emerging as an enabling technology that promises enhanced capabilities for spacecraft and space missions and can therefore play an important role in the future of in-space propulsion. Multimode propulsion has the potential to provide unprecedented flexibility and adaptability to spacecraft as a direct result of shared propellant and can provide mass savings for certain missions. These benefits can apply regardless of spacecraft size. Additional mass savings may be realized by sharing thruster hardware between modes, especially for …


Inkjet-Printed Ti3c2tx Mxene Electrodes For Multimodal Cutaneous Biosensing, Abdulelah Saleh, Shofarul Wustoni, Eloise Bihar, Jehad K. El-Demellawi, Yizhou Zhang, Adel Hama, Victor Druet, Arief Yudhanto, Gilles Lubineau, Husam N. Alshareef, Sahika Inal Oct 2020

Inkjet-Printed Ti3c2tx Mxene Electrodes For Multimodal Cutaneous Biosensing, Abdulelah Saleh, Shofarul Wustoni, Eloise Bihar, Jehad K. El-Demellawi, Yizhou Zhang, Adel Hama, Victor Druet, Arief Yudhanto, Gilles Lubineau, Husam N. Alshareef, Sahika Inal

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Among the existing two-dimensional materials, MXenes, i.e. transition metal carbides, nitrides and/or carbonitrides, stand out for their excellent electrochemical properties. Due to their high charge storage capacity, metal-like conductivity, biocompatibility as well as hydrophilicity, Ti3C2Tx MXene-based inks hold great potential for scalable production of skin conformable electronics via direct printing methods. Herein, we develop an aqueous MXene ink and inkjet-print MXene films on freestanding, flexible, and conducting polymer-based substrates. These skin-adherent MXene electrodes detect electrocardiography signals with high signal-to-noise ratio while exhibiting preserved electrical performance after 1000 cycles of bending with a 50 d long shelf life in ambient conditions. …