bluuebunny/crossref_metadata_2025_split huggingface dataset:
Variations of In-Plane Mechanical Properties of Cellular Structures With Different Hierarchical Organizations
Authors: Chakraborty Souvik , Hebert Dylan , Faisal Tanvir Rahman 
Published: February 2021

Abstract
Inspired by the nature, this study analyzes in-plane compressive responses of different modes of hierarchical architected structures with varying topologies. Architected cellular structures with two different unit cell topologies — square and kagome are considered, both having a relative density of 0.25. Each unit cell topology is designed with three different configurations. The base structure is the primitive one with solid homogeneous cell wall. The nested hierarchical structure is derived from the primitive one with cellular structuring in the cell wall. The third and final one is the fractal-like hierarchical structure, where same unit cells appear on different length scales. 3D printed structures were subjected to uniaxial compression to characterize their in-plane mechanical properties. The compressive stress-strain behaviors reveal that all the structures demonstrate the classical behavior of cellular structures followed by significant recovery of their initial shape upon load withdrawal. The energy absorptions demonstrated by the plateau regions before densification are not only governed by their structural topologies, but also largely governed by the configurations of hierarchical organizations. Hence, this study suggests the application specific design of hierarchical architected structures for defined loading conditions.
Design and Implementation of a Pulley-Based Movable LED System for Optimal Plant Growth
Authors: Ilhan Zeki Okan , Ok Jeong Tae , Eakins Brandon , Masters Clayton , Thompson Kelcee , Vital Tojya 
Published: February 2021

Abstract
A pulley-based movable LED light apparatus is designed and implemented based on a request from the Biology Department of the Midwestern State University to provide a controllable environment for plant research. The proposed apparatus consists of a large aluminum structure with added pulleys, the movable LED light platform, a DC-motor-driven gearbox, and electronics for sensing and control. The proposed conceptual design has been fabricated, tested, and successfully implemented in the MSU greenhouse. Performance of the initial design is also demonstrated through mechanical efficiency, light intensity profile, and the ultrasonic sensor sensitivity. Finally, some propositions are introduced to improve upon the hardware, sensors, and the control logic, that could allow for a better performance and an increased overall life span of the apparatus.
Experiential Learning in STEM for a Diverse Student Population at the University of the District of Columbia (UDC) Through the Implementation of the UDC Rover Project
Authors: D'Orazio Giancarlo , Xu Jiajun , Haghani Sasan 
Published: February 2021

Abstract
In 2018, the University of the District of Columbia (UDC) participated in the NASA Human Exploration Rover Challenge for the first time in the school’s history. An interdisciplinary team of students designed and fabricated a two-person, human-powered rover which competed against 100 other colleges and universities. Based on their success, in 2019 UDC again formed a team to participate in the challenge, improving on the 2018 rover design and performance. This paper reports the process of implementing this experiential learning activity and how this project has contributed to the STEM curriculum at UDC, and recruitment and participation of underrepresented STEM students. Lessons learned from implementing this project is also shared and discussed in this paper.
Combined Brayton, Inverse Brayton and Steam Cycles Power Plant
Authors: Carapellucci R. , Di Battista D. 
Published: February 2021

Abstract
Nowadays, more significant effort is needed to improve power generation efficiency to respond to environmental concerns. Several innovative technological options are under development and, among them, the integration of different energy systems is one remarkable opportunity.
In this work, a combination of three different thermodynamic cycles has been proposed and studied: an Inverted Brayton cycle (IBC) is used to exploit the exhaust gas enthalpy of a Brayton-Joule cycle and a Steam Power Plant is bottomed to the Inverted Brayton Cycle, in order to recover the high thermal power wasted in its cooling section. In other words, a quite conventional natural gas combined cycle power plant is repowered introducing the Inverted Brayton Cycle to exploit the gas thermal power between the gas turbine and the heat recovery steam generator.
In this integration, each parameter has a strong influence on the overall performance of the system: pressure ratio of the gas cycle, sub-atmospheric pressure of the inverted one, turbines inlet and outlet temperatures and heat recovery grade in the bottom steam section have been investigated in order to optimize the working conditions and find a best operating point. A post combustion opportunity was also considered, exploring for the best position to place it along the gases path and to get the maximum additional power through the repowering intervention.
Nonlinear Dynamics and Stability of Pressure-Loaded Shallow Spherical Caps
Authors: Iarriccio G. , Pellicano F. 
Published: February 2021

Abstract
In this work, the nonlinear dynamic response of a shallow spherical cap subjected to a time-dependent pressure load is analyzed. The Novozhilov’s nonlinear thin shell theory is used to express the strain-displacement relations, geometric imperfections are considered. Using the Rayleigh-Ritz method, the displacement fields are expanded using a mixed series: Legendre polynomials are considered in the azimuthal direction and harmonic functions in the circumferential one. The dynamic model is derived by using the Lagrange equations. The response of a homogeneous shell, made of isotropic material, clamped at its ends, and subjected to an external pressure load is investigated: using the continuation software AUTO, the bifurcation analysis of equilibrium points and periodic responses has been performed. The model is validated by means of comparison with the existing results in literature for spherical shells having a circular base, in particular with models developed through the Marguerre’s theory.
Optimum Tick Collection Material and Design for Autonomous Tick Collection Robot
Authors: Harrison Moretto Caroline “Niki” , Dong Janet , Qiu Yesiliang 
Published: February 2021

Abstract
This paper discusses the design and testing material utilized to collect ticks from rugged terrain in remote areas via a mobile robot using a mast system, focusing on locating the ideal design and material to ensure maximum tick collection without impacting mobility. Drags are used to collect ticks from short grass, and flags, in the air along the side of the robot, are used to collect ticks from tall grass and shrubs. The design was tested in the field and a laboratory. Cotton and sponge cloth materials were evaluated, along with the shape of the material.
The optimum design uses strips of rough sponge cloth to collect ticks. The roughness and fibrous nature of the material increase the number of ticks collected and performed the best of all materials tested. Seams in the sponge cloth allow them to tear away from the robot, if they become tangled in brush, to prevent the robot from being incapacitated. The thickness and weight of the sponge cloth also discourage the material from knotting and entangling with the robot or the environment.
The flag attachment points are adjustable horizontally to allow the rearrangement of strips for optimum tick collection. Each strip is designed for independent removal to contain ticks easily and replace strips quickly.
Attaching sponge cloth flagging and dragging strips to a mobile robot for tick collection protects humans from a potential illness from bugs and insects carrying disease pathogens, injury from traveling across rough ground, and harm due to exposure to the elements; productivity is also increased. The collection strips should capture ticks despite adverse conditions, be easily interchangeable, and not hinder the tick collection and removal process.
Dynamics of MEMS-Based Angular Rate Sensors Excited via External Electrostatic Forces
Authors: Gebrel Ibrahim F. , Wang Ligang , Asokanthan Samuel F. 
Published: February 2021

Abstract
This paper investigates the dynamic behavior of rotating MEMS-based vibratory gyroscopes which employs a thin ring as the vibrating flexible element. The mathematical model for the MEMS ring structure as well as a model for the nonlinear electrostatic excitation forces are formulated. Galerkin’s procedure is employed to reduce the equations of motion to a set of ordinary differential equations. Understanding the effects of nonlinear actuator dynamics is considered important for characterizing the dynamic behavior of such devices. A suitable theoretical model to generate nonlinear electrostatic force that acts on the MEMS ring structure is formulated. Dynamic responses in the driving and the sensing directions are examined via time responses, phase diagram, and Poincare’ map plots when the input angular motion and the nonlinear electrostatic force are considered simultaneously. The analysis is envisaged to aid fabrication of this class of devices as well as for providing design improvements in MEMS Ring-based Gyroscopes.
Distributed Sensor System for Underground Fuel Storage Facility Monitoring and Leak Detection
Authors: Nakamura Matthew , Hafner Noah , Brown Joseph J. 
Published: February 2021

Abstract
This work presents a sensor system to monitor environmental conditions in the vicinity of fuel storage tanks and facilities, providing measurements to help assess tank integrity and identify spills or leaks. The system utilizes a common hardware platform for multiple functional areas (e.g. base stations and sensing nodes) in the sensor network, simplifying manufacturing and logistics. The hardware platform was designed for low-cost manufacturing, adaptability, and versatility. It uses commercial off-the-shelf electronics in 3D-printed enclosures that were designed to optimize sensor and communication antenna placement. Pairing this hardware platform with a web-based data storage system and display client provides real-time telemetry visualization for monitoring tank facility conditions and can alert operators of potential leaks and hazards. The sensor system provides advances over current techniques in the form of scalability, cost minimization, live data reporting, and localization for active monitoring. Modularity reduces the engineering effort for adaptations to use new sensors in diverse environments, which can have different factors that lead to failures, and also allows the system to be updated as technology progresses. Data collected in experimental testing validates system functionality and ability to detect factors associated with spills and leaks.
Data-Driven Constitutive Modeling of the Progressive Softening in Elastomeric Gels With Interpenetrating Networks
Authors: Morovati Vahid , Ghaderi Aref , Dargazany Roozbeh 
Published: February 2021

Abstract
Solid though hydrogels are a class of bio-inspired elastomeric material with the ability of high stretch-ability, toughness, and water absorption. Though hydrogels exhibit nonlinear features such as stress softening, permanent set, cyclic energy dissipation and induced anisotropy in their mechanical responses. Besides, gels used in biomedical devices and soft robots are designed to sustain continuous cyclic loading during their service-life. While most studies assume that the majority of stress softening occurs in the first cycle. However, experimental studies suggest that the material exhibits damage accumulation and stiffness reduction significantly at higher number of cyclic loading. This progressive stress softening can lead to an unpredicted response of the material in dynamic loading as it is a function of material stiffness. However, there are only a few constitutive models developed to address this accumulative damage in the elastomeric gels. Thus, here, we developed a data-driven method to predict the behavior of hydrogels subjected to a high number of cycles. The developed model can be particularly used to estimate material response in each cycle and its steady-state response due to three-dimensional deformation. The strain energy of the material is the same in all direction in the undeformed state and damage evolve in each direction based on its maximum deformation. Moreover, the energy of the material in each direction estimated through two parallel artificial neural network. The proposed model shows good agreement with cyclic uni-axial tensile test data in different cycles of the loading and steady-state response of material.
Ultrasonic Acoustic Heterodyne Transmission Into the Human Auditory and Vestibular Systems
Authors: Dumm Christopher M. , Hiers Anna C. , Vipperman Jeffrey S. , Klinzing George E. , Balaban Carey D. 
Published: February 2021

Abstract
It is well-known that airborne sound induces vibration of the eardrum, the coupled middle ear bones, and the inner ear. Sound transmission to the inner ear is attenuated by damage or dysfunction in the eardrum or ossicular chain. Corrective devices often use contact shakers to directly vibrate the temporal bone of the skull, delivering sound. We investigate an alternative, noncontact method of sound transmission that uses ultrasonic signals to transmit sound into the auditory and vestibular systems. Minimal literature exists describing ultrasonic hearing, largely due to attenuation of air-conducted frequencies above 20 kHz. High-amplitude airborne sound incident upon the skull can induce temporal bone system vibrations along an unconventional structural path. Finite-element-based acoustic modeling of the auditory and vestibular anatomy reveals resonant behavior in structural components of the middle and inner ear at ultrasonic frequencies. These “built-in sound amplifiers” can be leveraged to compensate for impedance mismatches experienced in airborne ultrasound transmission. By heterodyning (amplitude modulating) a targeted ultrasonic carrier signal with an audio signal, the nonlinearities of acoustic propagation and the auditory and vestibular sense organs allow interpretation of heterodyne signals. These techniques provide a foundation to improve a wide variety of communication equipment, including hearing aids, without interfering with balance sensations.
Discrete Vortex Modeling of a Flapping Foil Energy Harvester With LEV Shedding Criterion
Authors: Kamrani Fard Kiana , Liburdy James A. 
Published: February 2021

Abstract
The energy harvesting performance of a flapping airfoil is studied through discrete vortex model. Results are obtained for a thin flat airfoil that undergoes a sinusoidal flapping motion for reduced frequencies of k = fC/U∞ = 0.06–0.16 where f is the heaving frequency of the foil, C is the chord length and U∞ is the freestream velocity. The airfoil pitches about the mid-chord and the heaving and pitching amplitudes of the airfoil are h0 = 0.5C and θ0 = 70° respectively, as these numbers have been shown to give optimal energy harvesting results for a rigid airfoil. The study applies a panel-based discrete vortex model that incorporates a leading edge suction parameter criterion to understand the flow behavior around the airfoil. The leading edge suction parameter is found from 2D CFD simulations (Navier-Stokes equations solved in Fluent) for all K values. A correlation between the critical leading edge suction parameter and reduced frequency is found from the identified critical LESP values. An empirical trailing edge separation correction is also applied to the transient force results since flow separation at the trailing edge is anticipated. The parameters of interest from the model are transient distributions of force, power output, and overall efficiency. Model results are then validated against 2D CFD simulations. The effect of reduced frequency on power production and overall efficiency is finally studied to identify the optimal reduced frequency for energy harvesting applications.
Determining Micro Droplet Profile Using Internal Reflection Interference Fringes
Authors: Kim Iltai Isaac , Li Yang , Park Jaesung 
Published: February 2021

Abstract
We introduce an optical diagnostics to determine the morphological features of liquid droplet such as the thickness, the contact angle, and the dual profile using internal reflection interferometry. A coherent laser beam is internally reflected on the air/liquid interface of a sessile droplet placed on a prism-based substrate to produce an interference fringe on a screen far from the substrate. The reflected laser rays consist of the reflection from the center spherical droplet profile and the one from the lower hyperbola-like droplet profile. The reflected rays are interfered each other to form the interference fringes. Ray tracing simulation is conducted using a custom-designed computer program. The simulation shows that the interfering rays reflected near the inflection point produce the outer-most fringes of the concentric interference pattern on the screen, and the reflected rays from the apex of the spherical profile and the contact line of the lower hyperbola-like profile construct the fringes at the center of the interference patterns. The simulated results are compared with the experimental observation to show a good agreement in the number and the location of the fringes and the radius of the outer-most-fringe where the number of the fringes is dependent on the droplet thickness and the radius of the fringe depends on the contact angle of the droplet. This result provides a new measurement technique to determine the morphological features of very small microdroplet such as the thickness (&lt; a few micron thickness), the contact angle (&lt; a few degree), and the dual-surface profile.
A Sequential Two-Step Design Framework for Deformable Mechanical Metamaterials
Authors: Patiballa Sree Kalyan , Krishnan Girish 
Published: February 2021

Abstract
Deformable metamaterials are materials that are made up of several repeating elastic building blocks whose geometries can be tailored to obtain a specified global shape change or stiffness behavior. They are deemed useful in soft robotics, shape morphing mechanisms, stretchable electronics, wearable devices, and devices that adapt according to their environment. This paper presents a two-step sequential design framework for the synthesis of deformable mechanical metamaterials where (a) topology optimization is used to map global deformation requirement to local elasticity matrix, followed by (b) a selection of building block microstructure geometry from a database and refining it to match the elasticity requirement. The first step is accomplished through a unique parameterization scheme that enables the classification of the planar orthotropic elasticity matrix into four distinct classes. The second step uses a kinetostatic framework known as load flow visualization to populate candidate microstructure geometries within these four classes. Finally, the framework is validated for the design of a cantilever beam with a specified lateral stiffness requirement and the design of planar sheets that exhibit sinusoidal deformation patterns.
Design and Construction of a Posterior Walker for Older Adults “Moviclinic”
Authors: Garrido Silva Gianina , Arguello Espinosa Juan Manuel , Maradey Lázaro Jessica Gissella , Bayona Velasco Geidy Alexandra , Suescun Mejia Angela Dayana 
Published: February 2021

Abstract
In recent years, the population of older adults (i.e age over 65) will double from 11% to 22% according to statistics from the World Health Organization (i.e WHO).
The assistive devices for gait (i.e Assistive Devices and Mobility Aids, ADMA) allow the movement and mobility of people with reduced abilities to walk, providing additional support of the human body to the ground. Some authors have classified these devices as fixed and mobile. Fixed devices are made up of parallel bars or handrails and mobile devices that include walking sticks, crutches, and walkers.
Especially, mobile devices allow the gait to be carried out by leaning on the device so that the patient will have greater stability and balance; as well as autonomy on regular terrain. Likewise, these reduce the risk of complications such as falls and immobilizations, which greatly improves the patient’s functionality and in rehabilitation can help to reduce pain in the muscles and joints by redistributing weight.
The “Moviclinic” rear walker is made up of a metal frame, equipped with forearm support and a front safety stop, which provides security for the user and his family. The rear wheels allow to direct the element and with the front wheels regulates the speed. Besides, it has an obstacle detection system which is based on the ultrasound principle, generating an audible alarm when detecting them with two priority levels, and the alarm system activated directly by the user. This feature always allows both the user and his family or caregiver to have peace of mind at all the times. Electronic design is also included.
This article aims to show the design, construction and validation of a support device for elderly patients with gait disturbances called “Moviclinic” based on the application of the “Design Thinking” methodology, Finite Element Analysis (FEA) and a technological surveillance analysis to make a comparison with current walkers and be able to offer a quality, efficient and affordable product. Finally, the test protocols carried out and the results obtained when testing their operation.
A Modified Network Alteration Model to Predict Quasi-Static Behavior of the Cross-Linked Polymers During Hydrolytic Aging
Authors: Bahrololoumi Amir , Mohammadi Hamid , Morovati Vahid , Dargazany Roozbeh 
Published: February 2021

Abstract
The network alteration theory is utilized to capture the effects of hydrolytic aging on the mechanical integrity of the polymer matrix. Hydrolytic degradation generally considered as a result of two simultaneous chemical phenomena; (i) reduction of the cross-links, and (ii) active chain loss. Assuming the alteration of the chain density is identical to the change of the number average molecular weight along the aging trajectory, the strain energy of polymer matrix can be rewritten as a function of deformation, deformation history, storage time, and aging temperature. The proposed model includes only five physically inspired material parameters. Thus, while it is computationally efficient, it shows good agreement with own experimental data, which performed on various range of accelerated aging temperatures and times. With respect to its computational efficiency, simplicity, accuracy, and interpret-ability, the model is a good choice for advanced implementations in FE programs.
Development of a Mobile Platform for Wheat Phenotyping
Authors: Pour Majid Khak , Fotouhi Reza , Hucl Pierre 
Published: February 2021

Abstract
Designing and implementing an affordable High-Throughput Phenotyping Platform (HTPP) for monitoring crops’ features in different stages of their growth can provide valuable information for crop-breeders to study possible correlation between genotypes and phenotypes. Conducting automatic field measurements can improve crop productions. In this research, we have focused on development of a mechatronic system, hardware and software, for a mobile field-based HTPP for autonomous crop monitoring for wheat field. The system can measure canopy’s height, temperature, vegetation indices and is able to take high quality photos of crops. The system includes developed software for data and image acquisition. The main contribution of this study is autonomous, reliable, and fast data collection for wheat and similar crops.