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Full-Text Articles in Mechanical Engineering

Wake Bifurcations Behind Two Circular Disks In Tandem Arrangement, Jianzhi Yang, Xiaowei Wu, Minghou Liu, Changjian Wang, Yuxin Wu, Zhihe Shen Jun 2022

Wake Bifurcations Behind Two Circular Disks In Tandem Arrangement, Jianzhi Yang, Xiaowei Wu, Minghou Liu, Changjian Wang, Yuxin Wu, Zhihe Shen

Mechanical and Materials Engineering Faculty Publications and Presentations

The wake bifurcations behind two circular disks in tandem arrangement are investigated through numerical simulations. The separation distance between the disks, S/d, is chosen at 1, 2, 4, and 6, and the Reynolds number, Re, lies in the range of 100 Re 500. The wake dynamics are examined in terms of the flow structures as well as drag and lift coefficient characteristics. Seven main wake regimes are observed in the considered (Re, S/d) space: steady state (SS), Zig-zig (Zz) mode, standing wave mode, periodic state with reflectional symmetry breaking (RSB), periodic state with double-helical (DH) structures shedding, periodic state with …


Latam Intelligent Filter For Education (Life), Andrew Lemus, Jonathan Woo, Edison Yang, Cinthya Jauregui, Daniel Mccann-Sayles Jun 2022

Latam Intelligent Filter For Education (Life), Andrew Lemus, Jonathan Woo, Edison Yang, Cinthya Jauregui, Daniel Mccann-Sayles

Interdisciplinary Design Senior Theses

The LIFE system is designed to inspire primary-aged students in Latin American schools to pursue higher education in STEM related fields. We hope the students educate others in their community about the public health implications stemming from the lack of clean water and grow to bring about more lasting solutions to the water crisis. Many family’s lives are stymied by the inability to access clean drinking water, with many students ending up spending hours carrying water or spending time recovering water themselves in lieu of attending school. The LIFE team created a tabletop water filter and pump system accompanied by …


Neurogen: Eeg And Near-Infrared Light Stimulation Device, Louisa Mantilla, Samantha Perez, Michelle Wong Jun 2022

Neurogen: Eeg And Near-Infrared Light Stimulation Device, Louisa Mantilla, Samantha Perez, Michelle Wong

Interdisciplinary Design Senior Theses

Neurodegenerative diseases such as Alzheimer’s, Dementia, and Parkinson’s affect hundreds of millions of people across the nation and world each year. While medications targeting disease pathways have often resulted in debilitating side effects, neurodegenerative diseases may be targeted by common pathways that promote healing of tissues via reduced inflammation, increased perfusion, and increased energy production. Photobiomodulation (PBM) targets all of these physiological processes with non-invasive near infra-red light stimulation and for this application the treatment will be applied to the head. Transcranial PBM has been used to effectively treat neurodegenerative diseases with improved cognitive and motor control outcomes. PBM applied …


San Francisco Space Saving Bike Rack, Silas Viskovich, James Mertke, Webster Mertke, Evan Josa Jun 2022

San Francisco Space Saving Bike Rack, Silas Viskovich, James Mertke, Webster Mertke, Evan Josa

Mechanical Engineering Senior Theses

Large cities like San Francisco can experience congested streets and crowded sidewalks. Increasing bike ridership has been shown to alleviate some of these pains, but they are currently being undersupported. In order to properly account for the growing cyclist population, more efficient bike storage solutions need to be made available. Current bike racks take up too much space, are not reasonably theft resistant, and are not adaptable to a variety of both indoor and outdoor spaces. In this paper, we designed and constructed a bike rack to take advantage of vertical space in order to reduce the footprint that storing …


How Advances In Low-G Plumbing Enable Space Exploration, Mark M. Weislogel, John Graft, Andrew P. Wollman, Karl Cardin, Logan Torres, J. E. Goodman, J. C. Buchli Jun 2022

How Advances In Low-G Plumbing Enable Space Exploration, Mark M. Weislogel, John Graft, Andrew P. Wollman, Karl Cardin, Logan Torres, J. E. Goodman, J. C. Buchli

Mechanical and Materials Engineering Faculty Publications and Presentations

In many ways, plumbing is essential to life support. In fact, the advance of humankind on Earth is directly linked to the advance of clean, healthy, reliable plumbing solutions. Shouldn’t this also be true for the advancement of humankind in space? Unfortunately, the reliability of even the simplest plumbing element aboard spacecraft is rarely that of its terrestrial counterpart. This state of affairs is due entirely to the near-weightless “low-g” state of orbiting and coast spacecraft. But the combined passive capillary effects of surface tension, wetting, and system geometry in space can be exploited to replace the passive role of …


Numerical Modelling Of Elastic Wave Propagation In Anisotropic Media Using The Finite-Difference Time Domain (Fdtd) And Elastodynamic Finite Integration Technique (Efit), Seth M. Golembeski Jun 2022

Numerical Modelling Of Elastic Wave Propagation In Anisotropic Media Using The Finite-Difference Time Domain (Fdtd) And Elastodynamic Finite Integration Technique (Efit), Seth M. Golembeski

Master's Theses

As ultrasonic testing becomes increasingly widespread, education and simulation in UT becomes increasingly useful. This thesis describes development of two simulations - the first, a Finite Difference Time Domain method that can be deployed to consumer GPUs. This simulation is designed to be user-friendly and provide quick interactivity for pedagogical use, for example, in a classroom or industry training. The second simulation is an anisotropic Elastodynamic Finite Integration Technique implementation, which can be deployed to high performance computers for large-scale parallel simulations. This anisotropic simulation is, to the author’s knowledge, the first open-source implementation of anisotropic EFIT.


Evaluating The Effects Of Granulated Rubber And Glass Fibers In Polymer Concrete As A Structural Material For Wafer Grinding Machines, Kevin Gabriel Kuehn, Philip Randall Streeter Jun 2022

Evaluating The Effects Of Granulated Rubber And Glass Fibers In Polymer Concrete As A Structural Material For Wafer Grinding Machines, Kevin Gabriel Kuehn, Philip Randall Streeter

Materials Engineering

Polymer concrete is a composite material used to replace cast iron and steel in wafer grinding machines for vibration damping. During the grinding and lapping processes of manufacturing silicon wafers, excessive vibrations may cause subsurface damage which requires additional polishing and reduces yield. Nine compositions containing various levels of granulated rubber and glass fibers were manufactured. CRM WRF-10 granulated rubber was examined at 0%, 5%, and 10% and Corning Cem-Fil glass fibers were added at 0%, 0.5%, and 1% by weight. Smooth-On EpoxAcast 690 epoxy resin was held constant at 16% for each composition. Crushed granite aggregate from Martin Marietta, …


Barker Bird Animatronic Senior Project Report, Marcus Monroe, Nolan Clapp, Ishan Jandaur, Jonathan Ogden Jun 2022

Barker Bird Animatronic Senior Project Report, Marcus Monroe, Nolan Clapp, Ishan Jandaur, Jonathan Ogden

Mechanical Engineering

This document describes how our F71 Senior Design Project team developed a 3D printed, electronic bird that mimics Disneyland’s first animatronic, the Barker Bird. An animatronic is a mechanical puppet that replicates real life movement with robotic parts. Disney’s Barker Bird is a well-known animatronic that replicates a talking macaw with multiple moving systems. The final prototype completed by our team serves as a teaching tool for CAPED (Cal Poly Amusement Park Engineers and Designers) club members that are interested in the field of animated robots.


Wave Goodbye To Salt, Andy Wu, Amanda Olla, Solie Grantham, Charlie Sinclair Jun 2022

Wave Goodbye To Salt, Andy Wu, Amanda Olla, Solie Grantham, Charlie Sinclair

Mechanical Engineering

Our team of Cal Poly Mechanical Engineers ideated, designed, built, and tested a system to help combat the growing problem of widespread drought in coastal and island communities. We developed a proof-of-concept model of a wave powered, mechanical system to desalinate ocean water using a reverse osmosis process. From topical research, it was found that there are many ways to harness a portion of the huge amount of energy that the ocean provides. While large scale ocean water desalination plants are already in operation, smaller scale desalination units powered by ocean waves are largely underdeveloped. Our relatively small and inexpensive …


Heating Lanyard To Warm Body Core, Cole Bunker, Spencer Alonge, Tyler Elsom, Matthew Hyland Jun 2022

Heating Lanyard To Warm Body Core, Cole Bunker, Spencer Alonge, Tyler Elsom, Matthew Hyland

Mechanical Engineering

Calculated Industries, a company that specializes in construction products headquartered in Carson City, Nevada, has sponsored the Heating Lanyard to Warm Body Core senior project. The objective of the project was to design and manufacture a body core heating device that will be used by construction workers to keep warm in cold environments. The goal is to create a device that is safe, comfortable, and temperature controllable. Our team consists of four mechanical engineering students at California Polytechnic State University, San Luis Obispo. Research was performed to analyze current products in the market, analyze how to best provide heat to …


Insulated Solar Electric Cooker With Phase Change Materials, Weijun Zhao, Jake Lung, Owen Chu, Sarah Melzer Jun 2022

Insulated Solar Electric Cooker With Phase Change Materials, Weijun Zhao, Jake Lung, Owen Chu, Sarah Melzer

Mechanical Engineering

This Senior Project Report documents the development and design process of the Insulated Solar Electric Cooker with a Phase Change Material (ISEC w/ PCM). In this project, we developed a PCM assembly that can be integrated into an existing ISEC system which utilizes two 100 W solar panels. This report details the use of a nitrate salt solution of 60% NaNO3 and 40% KNO3 and demonstrates its potential as a viable form of thermal storage solution for cooking. We found that only 1kg of PCM is able to retain its heat for around 5 hours after power removal and believe …


Insulated Solar Electric Cooker With Solid Thermal Storage, Eric M. Cortes, Andy M. Mccombs, Dominick Trageser, Nami Suzuki Jun 2022

Insulated Solar Electric Cooker With Solid Thermal Storage, Eric M. Cortes, Andy M. Mccombs, Dominick Trageser, Nami Suzuki

Mechanical Engineering

This Senior Project report outlines the design for our senior project under the Mechanical Engineering department of California Polytechnic State University. Insulated solar electric cookers (ISEC) are a relatively novel and exciting solution to the ethical, environmental, and medical issues associated with the conventional cooking methods - burning of biomass and charcoal - practiced in nonindustrial countries around the world. ISECs use solar energy input from a solar panel to cook food within an insulated chamber and have been researched and developed by Dr. Peter Schartz and his research group over the past several years. However, our target users expressed …


Shallow-Water Wind Turbine Foundation, Andrew Walker, Nico Nani, James Cusanelli, Zachary Dunkelberger Jun 2022

Shallow-Water Wind Turbine Foundation, Andrew Walker, Nico Nani, James Cusanelli, Zachary Dunkelberger

Mechanical Engineering

Over the 2021-2022 academic year, we, the Shallow Water Wind Turbine Foundation senior project team, designed, manufactured, and tested a fixed bottom, sand mounted turbine foundation for the Cal Poly Wind Power Club’s Collegiate Wind Competition turbine. The foundation was restricted to certain material, installation, and geometric constraints outlined in this report, and needed to support the turbine under operating conditions including 22 m/s wind speeds. The design was analyzed using primarily a bearing capacity geotechnical analysis to determine final geometry and weight. The foundation was then manufactured using welded, custom carbon steel parts.

The foundation was inspected for geometric …


Brush Clearing Trimming Device: Drivetrain, Dallas Russell, Nathan Small, Alex Imbery, Jordan Aguana Jun 2022

Brush Clearing Trimming Device: Drivetrain, Dallas Russell, Nathan Small, Alex Imbery, Jordan Aguana

Mechanical Engineering

We, the “DT Inc.” team, have been tasked with the redesign of the drivetrain of an electric brush clearing tool created for trail and roadside use. We started the design process by doing research on the currently available products and determining their strengths and shortcomings. We also tested the prototype given to us by our sponsor, and listened to our sponsor about what he liked about his design and what he wanted changed. We resolved from this research that the most important improvements that we needed to make were to improve the traction, reduce the speed and increase the torque, …


Baker/Koob Final Report: Solar Solution For Mini Mars Rover, Jonathan Cederquist, Cole Korchek, Derick Louie, Michaella Ochotorena, Collin Petersen Jun 2022

Baker/Koob Final Report: Solar Solution For Mini Mars Rover, Jonathan Cederquist, Cole Korchek, Derick Louie, Michaella Ochotorena, Collin Petersen

Mechanical Engineering

This project focused on designing, building, and testing a functional prototype of a collapsible solar array on the mini Mars rover being developed by client and sponsor, Mr. Rich Murray. Although many previous collapsible solar arrays have been deployed for space missions, the previous solar-powered Mars rovers only deployed their arrays once upon landing. This solar array will be able to collapse and deploy multiple times to allow for greater rover mobility and stability when the rover is not charging. This system is critical to the success of the rover project because it provides power without which the rover cannot …


Model Predictive Controller Design For Internal Combustion Engines Based On The Second Law Of Thermodynamics, Muataz Abotabik Jun 2022

Model Predictive Controller Design For Internal Combustion Engines Based On The Second Law Of Thermodynamics, Muataz Abotabik

Dissertations

Energy resources depletion and worldwide strict emissions policies pose challenges that automotive manufacturers try to overcome through researching advanced powertrain technologies such as lean-burn gasoline, direct injection, homogeneous charge compression ignition engines, powertrain electrification, etc. Most of these developments have been focused on conventional internal combustion engines (ICE) emissions and performance enhancements. Most ICE control strategies are built based on the First Law of Thermodynamics (FLT) i.e., to deliver a specific load requirement, enhancing thermal efficiency, etc. The FLT doesn’t account for in-cylinder high temperature thermodynamics process irreversibilities that cause losses in the work potential; up to 25% of the …


Me-Em Enewsbrief, June 2022, Department Of Mechanical Engineering-Engineering Mechanics, Michigan Technological University Jun 2022

Me-Em Enewsbrief, June 2022, Department Of Mechanical Engineering-Engineering Mechanics, Michigan Technological University

Department of Mechanical and Aerospace Engineering eNewsBrief

No abstract provided.


Grey-Taguchi Approach To Optimize Fused Deposition Modeling Process In Terms Of Mechanical Properties And Dimensional Accuracy, Md Asif Bin Syed, Qausar Rhaman, Hasan Md Shahriar, Mohammad Muhshin Aziz Khan Jun 2022

Grey-Taguchi Approach To Optimize Fused Deposition Modeling Process In Terms Of Mechanical Properties And Dimensional Accuracy, Md Asif Bin Syed, Qausar Rhaman, Hasan Md Shahriar, Mohammad Muhshin Aziz Khan

Graduate Student Scholarship

Fused Deposition Modeling (FDM) is a process that allows for the rapid production of functional parts through the deposition of fused material layers in a sequential manner. FDM has flexibility and the potential to create complicated parts. This study aims to optimize the FDM process parameters in terms of tensile strength, flexural strength, and longitudinal shrinkage using the Grey-Taguchi approach. The input parameters chosen to study the effects on dimension and mechanical properties are layer thickness, the raster angle, fill density, the number of contours, printing temperature, and printing speed. The Taguchi L27 orthogonal array is used as the statistical …


Model-Based Design Of An Optimal Lqg Regulator For A Piezoelectric Actuated Smart Structure Using A High-Precision Laser Interferometry Measurement System, Grant P. Gallagher Jun 2022

Model-Based Design Of An Optimal Lqg Regulator For A Piezoelectric Actuated Smart Structure Using A High-Precision Laser Interferometry Measurement System, Grant P. Gallagher

Master's Theses

Smart structure control systems commonly use piezoceramic sensors or accelerometers as vibration measurement devices. These measurement devices often produce noisy and/or low-precision signals, which makes it difficult to measure small-amplitude vibrations. Laser interferometry devices pose as an alternative high-precision position measurement method, capable of nanometer-scale resolution. The aim of this research is to utilize a model-based design approach to develop and implement a real-time Linear Quadratic Gaussian (LQG) regulator for a piezoelectric actuated smart structure using a high-precision laser interferometry measurement system to suppress the excitation of vibratory modes.

The analytical model of the smart structure is derived using the …


Development Of A Body Weight Reduction Algorithm In Micro-Gravity Treadmills™, Alexander Hibbert Jun 2022

Development Of A Body Weight Reduction Algorithm In Micro-Gravity Treadmills™, Alexander Hibbert

Master's Theses

Boost Treadmills™, a company specializing in the use of differential air-pressure (DAP) technology in the realm of exercise and rehabilitation, is developing their second-generation micro-gravity treadmill™ named the Boost 2. This machine will allow individuals in all types of fitness environments to move and exercise at a fraction of their normal body weight, reducing the impact forces on lower body extremities and allowing for accelerated returns to activity.

The purpose of this thesis was to create an algorithm to be implemented on the Boost 2 that related the percentage of body weight reduction of a user to a required pressure …


Aerodynamics And Aeroacoustics Optimization Of Vehicle’S Side Mirror Base And Exhaust Pipe, Moath Nayef Mohamed Zaareer Jun 2022

Aerodynamics And Aeroacoustics Optimization Of Vehicle’S Side Mirror Base And Exhaust Pipe, Moath Nayef Mohamed Zaareer

Theses

This thesis is concerned with studying two different vehicle parts in terms of aerodynamics and aeroacoustics. Two main factors determine the efficiency and luxury of the vehicle, the low aerodynamic forces and low noise emission. The aerodynamic drag coefficient is concerned with how easy a vehicle can travel through the air; the lower the value, the less fuel is needed to move the vehicle forward and less air resistance the vehicle faces. The aerodynamic lift coefficient is related to vehicle ground stability, and the more negative the value is, the higher the vehicle's stability. Moreover, the aeroacoustics is concerned with …


Flowunsteady: An Interactional Aerodynamics Solver For Multirotor Aircraft And Wind Energy, Eduardo Alvarez, Judd Mehr, Andrew Ning Jun 2022

Flowunsteady: An Interactional Aerodynamics Solver For Multirotor Aircraft And Wind Energy, Eduardo Alvarez, Judd Mehr, Andrew Ning

Faculty Publications

The ability to accurately and rapidly assess unsteady interactional aerodynamics is a shortcoming and bottleneck in the design of various next-generation aerospace systems: from electric vertical takeoff and landing (eVTOL) aircraft to airborne wind energy (AWE) and wind farms. In this study, we present a meshless CFD framework based on the reformulated vortex particle method (rVPM) for the analysis of complex interactional aerodynamics. The rVPM is a large eddy simulation (LES) solving the Navier-Stokes equations in their vorticity form. It uses a meshless Lagrangian scheme, which not only avoids the hurdles of mesh generation, but it also conserves the vortical …


Investigation Of Topological Phonons In Acoustic Metamaterials, Wenting Cheng May 2022

Investigation Of Topological Phonons In Acoustic Metamaterials, Wenting Cheng

Dissertations

Topological acoustics is a recent and intense area of research. It merges the knowledge of mathematical topology, condensed matter physics, and acoustics. At the same time, it has been pointed out that quasiperiodicity can greatly enhance the periodic table of topological systems. Because quasiperiodic patterns have an intrinsic global degree of freedom, which exists in the topological space called the hull of a pattern, where the shape traced in this topological space is called the phason. The hull augments the physical space, which opens a door to the physics of the integer quantum Hall effect (IQHE) in arbitrary dimensions. In …


Design And Control Of Next-Generation Uavs For Effectively Interacting With Environments, Caiwu Ding May 2022

Design And Control Of Next-Generation Uavs For Effectively Interacting With Environments, Caiwu Ding

Dissertations

In this dissertation, the design and control of a novel multirotor for aerial manipulation is studied, with the aim of endowing the aerial vehicle with more degrees of freedom of motion and stability when interacting with the environments. Firstly, it presents an energy-efficient adaptive robust tracking control method for a class of fully actuated, thrust vectoring unmanned aerial vehicles (UAVs) with parametric uncertainties including unknown moment of inertia, mass and center of mass, which would occur in aerial maneuvering and manipulation. The effectiveness of this method is demonstrated through simulation. Secondly, a humanoid robot arm is adopted to serve as …


Monolithic Integration Of Hybrid Perovskite Single Crystals With Silicon For Highly Sensitive X - Ray Detectors, Jinsong Huang, Wei Wei May 2022

Monolithic Integration Of Hybrid Perovskite Single Crystals With Silicon For Highly Sensitive X - Ray Detectors, Jinsong Huang, Wei Wei

Department of Mechanical and Materials Engineering: Faculty Publications

Perovskite single crystal X - ray radiation detector devices including an X - ray wavelength - responsive active layer including an organolead trihalide perovskite single crystal, a substrate layer comprising an oxide, and a binding layer disposed between the active layer and the substrate layer. The binding layer including a binding molecule having a first functional group that bonds to the organolead trihalide perovskite single crystal and a second functional bonds with the oxide. Inclusion of the binding layer advantageously reduces device noise while retaining signal intensity.


Integrating Deep Learning And Hydrodynamic Modeling To Improve The Great Lakes Forecast, Pengfei Xue, Aditya Wagh, Gangfeng Ma, Yilin Wang, Yongchao Yang, Tao Liu, Chenfu Huang May 2022

Integrating Deep Learning And Hydrodynamic Modeling To Improve The Great Lakes Forecast, Pengfei Xue, Aditya Wagh, Gangfeng Ma, Yilin Wang, Yongchao Yang, Tao Liu, Chenfu Huang

Michigan Tech Publications, Part 1

The Laurentian Great Lakes, one of the world’s largest surface freshwater systems, pose a modeling challenge in seasonal forecast and climate projection. While physics-based hydrodynamic modeling is a fundamental approach, improving the forecast accuracy remains critical. In recent years, machine learning (ML) has quickly emerged in geoscience applications, but its application to the Great Lakes hydrodynamic prediction is still in its early stages. This work is the first one to explore a deep learning approach to predicting spatiotemporal distributions of the lake surface temperature (LST) in the Great Lakes. Our study shows that the Long Short-Term Memory (LSTM) neural network, …


Simple, Accurate Calculation Of Mechanical Power In Pressure Controlled Ventilation (Pcv), Christine A. Trinkle, Richard N. Broaddus, Jamie L. Sturgill, Christopher M. Waters, Peter E. Morris May 2022

Simple, Accurate Calculation Of Mechanical Power In Pressure Controlled Ventilation (Pcv), Christine A. Trinkle, Richard N. Broaddus, Jamie L. Sturgill, Christopher M. Waters, Peter E. Morris

Mechanical Engineering Faculty Publications

Background: Mechanical power is a promising new metric to assess energy transfer from a mechanical ventilator to a patient, which combines the contributions of multiple parameters into a single comprehensive value. However, at present, most ventilators are not capable of calculating mechanical power automatically, so there is a need for a simple equation that can be used to estimate this parameter at the bedside. For volume-controlled ventilation (VCV), excellent equations exist for calculating power from basic ventilator parameters, but for pressure-controlled ventilation (PCV), an accurate, easy-to-use equation has been elusive.

Results: Here, we present a new power equation …


Free-Decay Heave Motion Of A Spherical Buoy, Jacob K. Colling, Saeed Jafari Kang, Esmaeil Dehdashti, Salman Husain, Hassan Masoud, Gordon Parker May 2022

Free-Decay Heave Motion Of A Spherical Buoy, Jacob K. Colling, Saeed Jafari Kang, Esmaeil Dehdashti, Salman Husain, Hassan Masoud, Gordon Parker

Michigan Tech Publications, Part 1

We examined the heave motion of a spherical buoy during a free-decay drop test. A comprehensive approach was adopted to study the oscillations of the buoy involving experimental measurements and complementary numerical simulations. The experiments were performed in a wave tank equipped with an array of high-speed motion-capture cameras and a set of high-precision wave gauges. The simulations included three sets of calculations with varying levels of sophistication. Specifically, in one set, the volume-of-fluid (VOF) method was used to solve the incompressible, two-phase, Navier–Stokes equations on an overset grid, whereas the calculations in other sets were based on Cummins and …


Cloudbots: Autonomous Atmospheric Explorers, Akash Binoj May 2022

Cloudbots: Autonomous Atmospheric Explorers, Akash Binoj

Honors Scholar Theses

The CloudBot is an autonomous weather balloon that operates on the principle of variable buoyancy to ascend and descend in the atmosphere. This project aims to develop a device that will collect atmospheric measurements and communicate them mid-flight. The apparatus consists of a helium-filled balloon, the robotic payload, and an air cell. The fixed-volume helium balloon at the top provides an upwards buoyancy force, while the air cell at the bottom can hold a variable amount of pressure to adjust the weight of the CloudBot. By doing so, it is able to travel in storm conditions and collect valuable atmospheric …


Natural Layered Mercury Antimony Sulfosalt Livingstonite With Anisotropic Optical Properties, Ravi P.N. Tripathi, Jie Gao, Xiaodong Yang May 2022

Natural Layered Mercury Antimony Sulfosalt Livingstonite With Anisotropic Optical Properties, Ravi P.N. Tripathi, Jie Gao, Xiaodong Yang

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Naturally occurring layered mineral livingstonite is identified as a new type of van der Waals (vdW) heterostructure based 2D material, consisting of two commensurately modulated alternating layers of HgSb2S4 and Sb2S4. The heterostructures of livingstonite crystal are prepared as thin flakes via mechanical exfoliation method. The prepared livingstonite crystals are further investigated in the context of vibrational, linear, and nonlinear optical properties, including anisotropic Raman scattering, wavelength-dependent linear dichroism (LD) transition effect, birefringence, and anisotropic third-harmonic generation (THG). Owing to the monoclinic crystal structure, livingstonite crystals exhibit strong anisotropic vibrational and optical responses. In contrast to conventional vdW heterostructures, the …