bluuebunny/crossref_metadata_2025 huggingface dataset:
Real-Time Prediction of Temperature Distribution in Additive Manufacturing Processes Based on Machine Learning
Authors: Bayat Sharareh , Mohseni Mohammad , Behnami Delaram , Abolmaesumi Purang
Published: February 2021

Simulation tools improve various aspects of the additive manufacturing process, however, they come with an undesirable computational time for real-world applications. Finite element analysis (FEA) that solves partial differential equations (PDE) presents promising capabilities in simple additive manufactured components as an expository problem. Yet, PDE-based solutions take significantly long CPU time due to a large number of timesteps required to simulate an additively manufactured part. With modern machine learning (ML) capabilities, a new shift towards integration of FEA and ML has been introduced, where ML algorithms emulate the behavior of the time-consuming PDE-solver for real-time analysis of PDE in a given application. In this paper, we present a deep learning (DL) model that can substitute the thermal analysis of the additive manufacturing process. The training data is obtained by sampling the established physical model’s behavior over different temperatures, cooling rates, and part’s geometries. The network architecture is composed of a Long Short-Term Memory (LSTM) to model the temporal sequence of deposition temperatures derived by PDEs. The reported R2 value on validations data is 97%, while the Mean Absolute Error (MAE) is 0.04. This paper compares the performance between the PDE and DL forecast for the thermal results. We show DL models are promising for simulation of the additive manufacturing process, and can be reliable alternatives for computationally-expensive FEM tools.
Bearing Fault Detection and Classification: A Framework Approach
Authors: Melgarejo Agudelo Carlos Fabián , Blanco Rodriguez John Jairo , Maradey Lázaro Jessica Gissella
Published: February 2021

Bearings are the major components in rotary machinery and very used in the industry. The time for bearing failures identification before interrupting operation or affecting product quality is the basis for most predictive maintenance programs. Taking readings, keeping history of failures and evaluating these results in the operation of rotating equipment on a regular basis, allows to detect possible failures before they become catastrophic. In this way, the damages or defects that are detected before a failure occurs, reduce the repair costs and the time that a rotating machine will be inactive. The bearing failures can generate losses due to machine downtime, unwanted vibration, noise and damage of other components, but if they are detected in time, repair costs and downtime are minimal.

This article shows in detail the different detection and classification techniques most used to identify bearing failures such as vibration analysis, artificial neural networks (i.e ANN), convolutional neural networks (i.e CNN) and support vector machine (i.e SVM) and the relevant features of each detection technique.
Numerical Modelling of Mineral-Slurry Like Flows in a 3D Lid-Driven Cavity Using a Finite Element Method Based Tool
Authors: Peralta Sergio , Córdova Jhon , Celis Cesar , Maza Danmer
Published: February 2021

A finite element method (FEM) based tool is used in this work to numerically modeling mineral-slurry like flows in a 3D lid-driven cavity. Accordingly, the context in which the referred FEM based tool is being developed is firstly emphasized. Both mathematical and numerical models utilized here are described next. A special emphasis is put on the flow governing equations and the particular FEM weighted residuals approach (Galerkin method) used to solve these equations. Since mineral-slurry flows both featuring relatively low flow velocities and containing large amounts of solid particles can be accounted for as laminar non-Newtonian flows, only laminar flows are discussed here. Indeed both Newtonian and non-Newtonian laminar flows are numerically studied using a 3D lid-driven cavity at two different Reynolds numbers. Two rheological models, power-law and Carreau-Yasuda, are utilized in the non-Newtonian flow simulations. When possible, the numerical results obtained here are compared with other numerical and experimental ones available in open literature. The associated averaged discrepancies from such comparisons are about 1%. The results obtained from the numerical simulations carried out here highlight the usefulness of the FEM based tool used in this work for realistically predicting the behavior of 3D Newtonian and non-Newtonian laminar flows. Multiphase turbulent flows including fluid-particle interaction models will be considered in future developments of this tool such to allow it properly representing the entire mineral-slurry transport phenomenon.
A New Electrode Design for Constant Volume Combustion Chamber
Authors: Shaffer James , Askari Omid
Published: February 2021

The current method of achieving center chamber ignition in the Plasma Combustion Research Laboratory’s (PCRL) Constant Volume Combustion Chamber (CVCC) utilizes either a standard or modified spark plug. The standard spark plug achieves a representation of side wall ignition (similar to a combustion engine) while modified sparkplugs have an extended electrode to allow for a center camber ignition. Two of these modified spark plugs are placed on both sides of the chamber and can effectively seal and isolate the chamber from the electrode. However, the process of welding electrode material to the spark plug is time consuming and requires a large number of modified electrodes to effectively test multiple different spark gap sizes. Also, the process of cleaning the electrode after experimentation shortens the electrode over time with no method of compensation other than creating a new electrode. The new electrode design aims to reduce the structural weakness by removing the welded joint as well as allowing for linear adjustment between testing while remaining firm during testing. The new design presented utilizes high-temperature epoxy, ceramic and grafoil seals to make adjustments easy and precise. The design was analyzed, prior to building and testing, based on the stress induced from the sealant, the total rated voltage, the rated temperature, and the fracture stress of the ceramic material. The stress induced in the electrode device was analyzed with FEA and the results were found to be within the limits of the material in terms of the compressive and fracture strength. The maximum voltage was found to be around 30 kV. The design is tested with 3 different electrode sizes where the largest electrode of 1.3 mm (0.05 in) has the same diameter as the current experimental set up. Two smaller electrodes 1 mm and 0.5 mm (0.04 in and 0.02 in) are tested as well to show the range and capabilities of the new system. The voltage and current data of the new and old system are compared and are found to be statistically similar within a 90 percent confidence level. The new electrodes is also compared to the previous system in terms of electrical resistance, the peak power each system can provide to the plasma, the visual shape and duration of the plasma through high speed photography. The range of operation for a successful design includes pressures from 20 mTorr to 40 atm, temperatures up to 280 C, and voltages up to 25 kV.
Development of Educational Mobile Soccer Platform Teaching Mechanical Design and Fabrication for Mechanical Engineering
Authors: Lee Hyun Jae , Sim Yu seop , Park Hwi Jin , Park Hoon Min , Yi Hak
Published: February 2021

The mobile platform is an attractive educational tool that has brought to myriad effective benefits for a variety of the application fields. Furthermore, application of the mobile platform to engineering education has greatly assisted the engineering students’ firsthand experiences in college. However, most of the robotics classes offered today are concentrating on mechatronics and software education. For the advancement, this paper develops the mobile platform for the effective curriculum in teaching design and fabrication of robots in the house. The design of the proposed mobile platform bases on the knowledge of the majors subject from mechanical engineering. Through the dynamic simulation, the possibility of an introduction of the developed platform to robotics education is verified. Dynamic simulation experiments with the maximum velocity and acceleration of this system are carried out to check the application for educational purposes. As a final step, components of the platform are fabricated and assembled.
Numerical Study of the Effects of Confined Airfoils Usage in High Bypass Ratio Turbofan Engines
Authors: Aguilar Rene , Celis Cesar , Pontes Marcio
Published: February 2021

Turbofan engines are the main power plants used in the commercial airline industry. Increasing the bypass ratio (BPR) in turbofan engines enhances their propulsive efficiency and reduces both noise and harmful gas emissions. Over the years the aero engine industry has devoted huge efforts and enormous amounts of money to improve turbofans’ propulsive efficiency through the increase of their BPR. Based on the current technology however, there is a practical limit to how much BPR can be increased before significant penalties associated with increased both engine weight and nacelle drag erode the benefits. This work numerically studies thus the benefits of using confined airfoils in the engine bypass flow region to counteract the turbofan engine weight and alleviate the efforts over the aircraft wing structure. Accordingly, a description of the proposed engine-airfoils arrangement, relative dimensions and airfoils adequate placement inside the engine bypass duct is initially presented. Two different flight conditions, take-off and cruise, are numerically assessed next using computational fluid dynamics (CFD) based approaches to characterize the particular bypass flow behavior. The numerical work includes the study of engine configurations similar to those used in long-range aircraft. A structured multi-domain mesh, in conjunction with both Reynolds-average Navier Stokes (RANS) and steady-state mixing planes approaches, are used in the numerical model utilized. The main results indicate that using confined airfoils produces substantial lift respect to the engine weight. Engine weight reductions of up to 23% are observed because of the use of confined airfoils in the engines bypass ducts.
Investigating the Design and Manufacture of PneuNet Actuators As a Prosthetic Tongue for Mimicking Human Deglutition
Authors: Araya Francis Darmont , Radhakrishnan Pradeep
Published: February 2021

The number of Total Glossectomy cases in the United States is seeing an increasing trend as per the Nationwide Inpatient Sample Database. Patients, who have undergone such aggressive surgical procedures, have extensive limitations performing basic oral functions such as swallowing (deglutition), eating and speaking. Current rehabilitation prostheses do little in restoring the functionality of the original tongue. This is true especially in deglutition, which is necessary to transfer a bolus to the esophagus. Such patients need advanced prosthetic devices and through this research, investigations into potential solutions for prosthetic tongues to aid in deglutition were carried out. Different designs were considered and based on a decision matrix, PneuNets (pneumatic networks) were adopted as the foundational basis for generating prosthetic tongue designs. Several prototypes were fabricated that used the Fused Filament Deposition process for producing the mold and silicone Eco-flex 00-30 for producing the mechanism. The resulting mechanism was powered using a pneumatic input and kinematic data was collected. Details from literature review, design iterations, simulations, validation processes, manufacturing challenges and conclusions will be discussed in depth in this paper.
Comparison of Epoxy Coating Degradations Under Impingement Flow and Stationary Immersion
Authors: Vedadi Amin , Parvej M. Subbir , Wang Xinnan , Wang Yechun
Published: February 2021

Offshore wind turbines are considered as a reliable source of electricity generation. However, due to the large cost of the construction and installation of offshore wind turbines, most wind turbines are designed to operate for more than 20 years. One of the biggest issues which causes a severe damage to the construction of wind turbines is the existence of a very corrosive environment including large mechanical loads applied to the construction by the waves and the high concentration of salt and other chemicals in the sea water. The construction of offshore wind turbine can be divided into four main regions based on the types of exposure to the water and the corrosive environment, including submerged zone, tidal zone, splash zone, and atmospheric zone. In this study, experiments were conducted to compare the impact of impingement flow of 3.5 w.t.% NaCl solution on the epoxy coating samples to the exposure of the same type of samples to a stationary 3.5 w.t.% NaCl solution. Those two exposure conditions correspond to the environments at the top and the bottom part of the submerged zone of offshore wind turbines respectively. Electrochemical Impedance Spectroscopy (EIS) method was used to monitor the degradation of organic coatings. The surface roughness was measured by Atomic Force Microscope (AFM). The roughness of the coated surfaces before and after the exposure was compared. For the two different flow conditions, i.e. impingement flow and stationary immersion, significant differences have been discovered from the EIS results and AFM results. We observed a more severe degradation in the epoxy coatings in impingement flow, and a rougher surface is formed for coating samples subjected to impingement flow.
Tribology and Electrochemical Corrosion Properties of TiC Thin Film Coatings Grown by RF Magnetron Sputtering
Authors: Olayinka Abegunde , Esther Akinlabi , Philip Oladijo
Published: February 2021

Titanium alloys have found application in many sectors and are regarded as one of the most valuable materials of the 21st century. Although titanium alloys have many promising properties, the tribo-corrosion properties still happen to be a limiting factor. In this research study, radio frequency (RF) magnetron sputtering was used to deposit refractory ceramic (TiC) thin films coatings on the surface of titanium alloys in order to enhance and improve the wear and corrosion resistance properties. Different combinations of the sputtering process parameters were used for the deposition process. The varied sputtering process parameters were RF Power, sputtering time, and temperature. The macroscratch, microscratch (adhesion test) and, corrosion properties of the coatings were investigated using the pin on-disk wear test, micro-scratch tribometer, and electrochemical potentiostat, respectively. The results show improvement in the wear and corrosion properties of the coated samples. The results also revealed the influence of the sputtering process parameters on the evolving wear and corrosion properties of the coated samples. Scanning electron microscope (SEM) was used to capture the wear scar and analyses the failure mode of the coatings.
Design and Experimental Evaluation of Mosquito-Inspired Needle Structure in Soft Materials
Authors: Gidde Sai Teja Reddy , Hutapea Parsaoran
Published: February 2021

Insects steer their stingers effortlessly to a specific target and release their venom in a certain path through the skin with minimal pain. These unique traits inspire the idea to develop bioinspired needles to reduce the insertion forces and to decrease the needle path deviation (deflection) for improved targeting accuracy. Our approach in this work focus on the design of mosquito-inspired needle and evaluation of the needle performance using vibration during tissue insertion. The mosquito-inspired needle design specifically consists of maxilla-shaped and labrum-tip design. The insertion force was measured using a force sensor, which was fixed at the needle end to measure the uniaxial force of needles. The applied vibration on the needle was measured along linear axis using piezoelectric actuator with a frequency of 150 Hz and an amplitude of 5μm. The needle was inserted at a constant speed by attaching the needle to a motorized linear stage. It was observed that the insertion forces of the proposed needle design with vibration showed a reduction by 27% compared to that of a conventional needle. This reduction in insertion force means that there is decrease in tissue gel phantom damage and it was also observed that needle bending has reduced due to reduction in bending stiffness of the tissue phantom. Furthermore, the needle insertion tests in real tissues (bovine kidney) considering the proposed needle geometry and vibration will be studied in future work to understand the bioinspired needle-tissue interactions.
Surface Acoustic Wave Sensors for Temperature and Strain Measurements
Authors: Yan Yang , Wang Yudong , Li Fang
Published: February 2021

It is highly desired to develop an inexpensive, wireless embedded sensor system that can provide high-bandwidth measurements of temperature and pressure inside a pipeline for rocket propulsion test applications. The fuel is generally liquid hydrogen and liquid oxygen, which must be kept at cryogenic temperatures. The environment places additional requirements on the design of sensors that is beyond the scope of most available products. Surface acoustic wave (SAW) technology has received considerable attention for harsh environment applications. The ultimate goal of our research is to develop a SAW sensor system for temperature and pressure sensing in the cryogenic environment. In this paper, the temperature testing of the SAW sensor was finished from 30 to 80°C. The strain testing was performed at room temperature. The results have shown that the temperature coefficient of the delay (TCD) at the room temperature is around 74.4 ppm/°C. The Strain coefficient of delay (SCD) of the testing result is 0.38 ppm/με at room temperature.
Thermal Conductance of Nanoparticles: A Study of Phonon Transport in Functionalized Nanodiamond Suspensions
Authors: Bain Aaron , Languri Ethan , Padmanabhan Venkat , Davidson Jim , Kerns David
Published: February 2021

Nanoparticle additives, with their anomalous thermal conductivity, have attracted attention in research and industry as a novel mode of enhancing the heat transfer mediums. Most studies conducted on nanoparticle suspensions in liquids, pastes, or composites at present have relied on constitutive relations using properties of the bulk substance and of the nanoparticle to explain the effective thermal conductivity. In order to utilize nanoparticles in real world engineering applications, chemical functionalization of the surface of the nanoparticle is frequently employed, either to suspend in liquid applications or to stabilize in arrays. In this study, we have sought to explain the underlying mechanisms of thermal conductivity enhancement taking into consideration the nanoscale effects, such as phonon transport in the nanoparticle coupled with vibrational modes of the surface functional molecules, in order to tailor the functional groups not only for suspension stability but also for minimizing Kapitza resistance at the surface of the nanoparticle. Density functional theory simulations in SIESTA and equilibrium transport theory analysis via GOLLUM2 were used in tandem to evaluate the thermal transport at the nanoparticle to surface ligand junction. By treating the nanoparticle surface and the polymer or acid coating as distinct homogeneous substrates, a model for thermal conductivity becomes more tractable.
Extending the Capabilities of Digital Human Modeling: A Design Framework to Assess Emergencies Early in Design
Authors: Gawand Mihir Sunil , Demirel H. Onan
Published: February 2021

Digital Human Modeling (DHM) brings in the advantages of reducing the time and cost spent on building physical prototypes and minimizing the risk of conducting human-subject data collection in hazardous settings. However, most of the DHM studies focus on evaluating standardized tasks executed in normal or nominal work conditions. There is a limited existing DHM research that focuses on the analysis of high-risk tasks performed during emergencies. This paper introduces a DHM based design framework that focuses on the ergonomics evaluation of high-risk tasks that are required to be performed during an emergency. The research aims to provide a methodology that can be used to measure the effect on the visibility of the controls due to a fire or smoke emergency in a civilian aircraft cockpit. The design framework described in this paper also automates the repetitive task simulations and ergonomic evaluations, which are typically performed manually by the designer. Thus, the automation module saves time and allows the consideration of a large sample set of anthropometries for assessing ergonomic adequacies. The automation framework also brings in the advantage of making the emergency assessments part of the early design ergonomics analysis digitally, which has not been the focus of traditional ergonomics studies.
Driver Distraction Detection and Recognition
Authors: Chinta Kiran Kumar , Barez Fred
Published: February 2021

Statistics have shown that the main reason for traffic accidents is human error. Modern vehicles are equipped to protect occupants in the event of a crash. The latest advanced vehicles come with driver behavior monitoring systems in recent years, and many have been proven to be effective systems in the prevention of accidents. However, these systems do not provide a complete solution and can only detect driver fatigue or driver distraction.

This project aims to build an AI model for sensing the distraction of drivers and identifying the kind of distraction using the Kinect sensor and the Brio camera and reorient driver’s attention on driving. For this, the system is divided into three sub-segments; calling arm position (arms up or down, arms right or left), facial expressions (blinking and mouth), and head orientation. Each segment develops important info for gauging the distraction of a driver based on the depth mapping of data and color from the Kinect sensor and Brio camera respectively. Testing on a driving simulator is completed on 4 different drivers of diverse ethnicity, sex, and age along with over 240 mins of recorded material. Since all the segments were recorded and prepared separately, they can further be taken to build different outcomes and can be implemented for real car systems.
Effective Deformations of Peristatic Random Structure Bar Subjected to Inhomogeneous Body-Forces
Authors: Buryachenko Valeriy A.
Published: February 2021

A statistically homogeneous random bar with the bond-based peridynamic properties of constituents is considered for a static case. Estimation of effective properties for the random structure peridynamic composites can be considered as a straightforward generalisation of the corresponding classical results for locally elastic composites which were obtained for both statistically homogeneous composites and homogeneous remote loading. In such a case the effective properties of both the peri-dynamic composites and locally elastic ones are described by a constant tensor of local stifness. However, even for locally elastic composites subjected to inhomogeneous loading, the effective deformations are described by a nonlocal (either the differential or integral) operator relaiting a statistical average of stresses in the point with a statistical average of strains in the vicinity of the point being considered. On the other hand, to the best authors’ knowledge, there are no academic publications analyzing the mentioned effective deformations of locally elastic composites due to prescribed inhomogeneous body-forces. Thus, the current paper deducated to the estimation of effective deformatiobs of 1D statistically homogeneous peridynamic composite bar for the prescribed self equilibrated body-forces has no known locally elastic counterpart. A sabsequent simplification is described by the dilute approximation method assuming coinsidence of the effective field (acting on the inclusions) with the applied field when interaction of inclusions is neglegible. The method is based on estimation of a perturbator introduced by one inclusion that is, in fact, the solutions of the basic problem for one inclusion inside the infinite peristatic matrix subjected to the body-force. The statistical averages of both the displacement and stresses are estimated by summation of these perturbators for all possible location of inclusions.
A Methodology for Tracking Control for Formation Flight of Satellites
Authors: Cho Hancheol , Udwadia Firdaus E.
Published: February 2021

This paper develops a methodology for the tracking control of satellite formation flight in the presence of external disturbances. The control methodology is composed of two steps. In the first step, an exact control strategy is developed for a nominal system model which provides the best assessment of real-life uncertainties. Upon using results from analytical dynamics, a closed-form control input is derived such that the formation configuration requirements are satisfied. In the second step, an additive robust controller is designed to compensate for the external disturbances to which the satellite formation system may be subjected. A gain adaptation law is developed that automatically updates the control gain in real time to adjust for the presence of environmental disturbances while keeping the precision of the tracking to within user-specified bounds. An additive combination of the two controllers enables precision tracking control for the satellite formation without a priori information about the bounds on the uncertainties and disturbances imposed on the formation system. Numerical simulations demonstrate the accuracy and effectiveness of the proposed two-step control methodology in which a desired formation configuration is to be maintained under unknown environmental disturbances.
On the Passive Noise Control of the Flow-Induced Noise Using Porous Materials
Authors: Nishikawa Reon , Terashima Osamu , Inasawa Ayumu
Published: February 2021

A passive noise control technique for the flow-induced noise using a porous material was studied experimentally. The purpose of this study was to decrease the aerodynamic sound using porous material that permeated only sound and clarify that reduction mechanism. In the experiment, flow-induced noises emitted from two types of rectangular cylinders was measured in a low-noise wind tunnel. One cylinder was made of four aluminum plates and the other was two aluminum and porous material plates each. Measurement results show that the frequency of the distinct tonal noise was different between two cylinders, that frequency was higher for using porous material. It was also found that the sound pressure level of the noise was also different and that of the cylinder using porous material plate was 25 dB smaller at maximum. Velocity field of the wake of cylinders were examined by the PIV measurement and that showed that time and space scale of separated vortices around cylinder were smaller for using porous material. It is assumed that the change of aerodynamic sound was caused by that change in velocity field.
Toxicity of Nanoparticles Used in Minimum Quantity Lubrication (MQL) Machining: A Sustainability Analysis
Authors: Nouzil Ibrahim , Eltaggaz Abdelkrem , Deiab Ibrahim , Pervaiz Salman
Published: February 2021

Minimum quantity lubrication (MQL) with nanocomposite particles is among the new areas of study and has proven to provide very good cooling and lubrication in the machining of difficult to cut materials, such as titanium, Inconel and ADI. It is therefore imperative to understand their effects on the environment in the early stages of investigation, prior to their wide scale usage in industry. This study focuses on the different nanocomposite particles used in previous research, which is available in the literature, and evaluates their sustainability characteristics by investigating the toxicity of these nanocomposite particles on humans. The cooling capabilities of each of the nanoparticles considered is first established from the existing literature and summarized. Human cell viability measured from in vitro toxicity studies of nanoparticles is used as a variable to easily capture the toxicity of nanoparticles. Six different human cell lines were chosen to represent the effects of possible exposure through inhalation [human lung epithelial cells (A549), and bronchial epithelial cells (NL-20)], ingestion (AGS, and HepG2) and dermal contact (THP-1, and human peripheral blood cells). A comparison table was developed (Table 2.0), which provides easy interpretation of the toxicity levels of the five nanoparticles that were considered using all three human cell lines. The drawback of this comparison is the lack of sufficient data to assign conclusive toxicity levels to the nanoparticles. The toxicity studies of nanoparticles on humans is still in its infancy and contradictory results exist for some of the nanoparticles. This is the first attempt to combine the results of the experimental investigations of nano-MQL cooling and the toxicity studies of nanoparticles, allowing researchers to make informed decisions in the selection of the most sustainable nanoparticles in the nano-MQL machining process.
Experiences of Teaching Hands-on Classes in Places Where They Are Rare
Authors: Das Shuvra
Published: February 2021

Engineering education in many countries still follows a traditional model where the curriculum is broadly divided into lecture-based theory classes and laboratory classes where experiments are conducted by students using step by step instructions. This type of curriculum has heavy emphasis on theory and less on exploration, application and design. In this model, opportunities for students to do hands-on activities such as building hardware and deal with troubleshooting, writing simulation models and learning by failing, etc. are quite limited. Also, many instructors in these systems are uncomfortable to adopt more hands-on teaching for the fear of failure. In 2019, in China, I taught a freshmen-level course on Introduction to Robotics using Arduino-based hardware where the students had to work in teams to build and program a mobile robot using parts that were provided to them. In 2020, I taught two classes in India for junior/senior level students on Modeling and Simulation of Mechatronic Systems and Modeling and Simulation of Hybrid Vehicles, respectively. In both courses the students spent over 80% of class time developing models and running simulations. In all three courses, enrolling about 60 students each, extensive survey-based assessment showed students are hungry for this type of hands-on experience and would be embracing these types of classes with a lot of enthusiasm. This paper discusses the details of the three classes and results from all the survey-based assessments that were done in the courses.
Direct Write Additive Manufacturing of High-Strength, Short Fiber Reinforced Sandwich Panels
Authors: Nawafleh Nashat , Celik Emrah
Published: February 2021

Additive manufacturing (AM) is a novel technology which allows fabrication of complex geometries from digital representations without tooling. In addition, this technology results in low material waste, short lead times and cost reduction especially for the production of parts in low quantities. Current additive manufacturing processes developed for thermoplastic sandwich panels suffer from an unavoidable weak mechanical performance and low thermal resistance. To overcome these limitations, emphasis is paid in this study on direct write AM technology for the fabrication of short carbon fiber-reinforced sandwich panel composites. Sandwich panels using different infill densities with high strength (> 107 MPa), and high short carbon fiber volume (46%) were attained successfully. In parallel to the strength enhancement, these sandwich panels possessed reduced densities (0.72 g/cc3) due to their lightweight lattice core structures. The mechanical performance of the created sandwich panels was examined and compared to the unreinforced, base ink structures by performing compression tests. Successful fabrication and characterization of the additively manufactured thermoset-based carbon fiber reinforced, sandwich panels in this study can extend the range of applications for AM composites that require lightweight structures, high mechanical performance as well as the desired component complexity.
Finite Difference Time Domain Simulations of Hybrid Neurotransducers Based Optical Microlasers
Authors: Manzo Maurizio , Cavazos Omar
Published: February 2021

Different pathologies such as Alzheimer’s, Parkinson’s, Wilson’s diseases, and chronic traumatic encephalopathy due to blasts and impacts affect the brain functions altering the neuronal electrical activity. An important aspect of the brain study is the use of non-invasive, non-surgical methodologies that are suitable to the well-being of the patients. Only a portion of the electromagnetic field can be detected by applying sensors outside the scalp; in addition, surgery is often involved if sensors are applied in the subcutaneous region of the skull. Optical techniques applied to biomedical research and diagnostics have been spread during the last decades. For example, near infrared light (NIR) of spectral range goes from 800 nm to 1300 nm, it is harmless radiation for the living tissue, and can penetrate the living matter in depth as, it turns out that most of the living matter is transparent to the NIR light. Optical microlasers have been recently proposed as neurotransducers for minimally invasive neuron activity detection for the next generation of brain-computer interface (BCI) systems. They are lightweight, require low power consumption and exhibit low latency. This novel sensor that can be made of biocompatible material is coupled with a voltage sensitive dye; the fluorescence of the dye, which is excited by an external light source, is used to generate optical (laser) modes. Any variation in the neurons’ membrane electric potential via evanescent field’s perturbation turn affect the shifting of these laser modes. In order to reduce the energy required to power these devices and to improve their optical emission, metal nanoparticles can be coupled in order to use their plasmonic effect. In this paper, finite-difference timedomain (FDTD) numerical technique is used to analyze the performances on a dye-doped microlaser. Purcell effect and resonant wavelengths are observed.
Reverse Engineering a Hedge Trimmer: A Practical Approach to Incorporate Geometric Dimensioning and Tolerancing (GD&T) Effectively in an Undergraduate Freshman Engineering Course
Authors: Kocharian Tikran , Manoharan Sanjivan
Published: February 2021

Geometric Dimensioning and Tolerancing (GD&T), due to the inherent complexity, is a challenging topic to teach and learn, especially at the undergraduate freshman level. Many institutes either cover GD&T on a superficial level or choose to overlook it. Incorporating such a broad subject in an already busy curricula remains a major challenge for many academic institutes, including ours. The knowledge and skill level of our students in GD&T at the beginning of their co-op is a major concern for several employers. These employers have to expend significant resources to train our students and graduates. To address this growing concern, a practical project was incorporated into a freshman introductory engineering course; a Ryobi hedge trimmer Model No. RY39500 was utilized. The students were divided into five groups, and each group was given a mechanical component from the assembly. First, each group was tasked with taking the necessary measurements to create a Computer Aided Design (CAD) model of their component in an effort to commence the reverse engineering process. The CAD model was then additively manufactured using fused deposition modeling. A detailed drawing of each component was created and GD&T concepts and symbols were applied to the drawing following ASME/ANSI Y14.5-2009 standards. The project was very well received by the students. It enhanced their understanding and skills necessary to implement GD&T concepts and symbols both in practice and in preparing engineering drawings. The 3-D printed parts were shared among the groups and the manufactured parts were fit together to replicate the real life assembling.
Camera-Based Coaxial Melt Pool Monitoring Data Registration for Laser Powder Bed Fusion Additive Manufacturing
Authors: Lu Yan , Yang Zhuo , Kim Jaehyuk , Cho Hyunbo , Yeung Ho
Published: February 2021

The quality of powder bed fusion (PBF) built parts is highly correlated to the melt pool characteristics. Camera-based coaxial melt pool monitoring (MPM) is widely applied today because it provides high-resolution monitoring on the time and length scales necessary for deep PBF process understanding, in-process defect detection, and real-time control. For such functions, MPM data has to be registered correctly to a well-defined coordinate system. This paper presents methods for camera-based coaxial melt pool monitoring (MPM) data registration using the build volume coordinate system defined in ISO/ASTM52921, for both open architecture AM systems and 3rd party MPM augmented closed commercial systems. Uncertainties are evaluated for the proposed methods and case studies provided to demonstrate the effectiveness of the methods.
Piezoelectric Performance of PVDF Composites for Transportation Engineering: A Multi-Scale Simulation Study
Authors: Yin Xiao-Hong , Jian Jin-Wen , Yang Can , Lei Tian , Cheng Tao
Published: February 2021

In the present work, the poly (vinylidene fluoride) composite filled with the lead zirconium titanate (PVDF/PZT) was numerically investigated focusing on the improvement of piezoelectric performance parameters. With a multi-scale simulation strategy, effects of the PZT fillers’ orientation and length on the electrical outputs of the piezoelectric energy collectors buried in the roads were systematically examined. Specifically, at the micro-scale, based on our previous research results, Comsol Multiphysics connected with Matlab was utilized to create the unit cell of piezoelectric composites. The simulation results showed that parameters of PZT nano-fillers greatly affect the piezoelectric coefficients. For the macro-scale simulation, a road energy collector with innovative symmetrical cantilever structure was designed, with piezoelectric constants obtained at micro-scale simulation as inputs. The correlation between the output voltage of the energy-collector and PZT parameters (i.e., orientation and length) was successfully developed by applying the vehicle’s axle-load. This work provides a way for tailoring the piezoelectric performance of the macro components (i.e., sensors) through adjusting the states of the fillers inside the piezoelectric composites.
GMRES Solver for MLPG Method Applied to Heat Conduction
Authors: Singh Abhishek Kumar , Singh Krishna Mohan
Published: February 2021

In recent years, meshless local Petrov-Galerkin (MLPG) method has emerged as the promising choice for solving variety of scientific and engineering problems. MLPG formulation leads to a non-symmetric system of algebraic equations. Iterative methods (such as GMRES and BiCGSTAB methods) are more competent than the direct solvers for solving a general linear system of larger size (order of millions or billions). This paper presents the use of GMRES solver with MLPG method for the very first time. The restarted version of the GMRES method is applied in connection with the interpolating MLPG method, to solve steady-state heat conduction in three-dimensional regular geometry. The performance of GMRES solver (with and without preconditioner) has been compared with the preconditioned BiCGSTAB method in terms of computation time and convergence behaviour. Jacobi and successive over-relaxation methods have been used as preconditioners in both the solvers. The results show that GMRES solver takes about 18 to 20% less CPU time than the BiCGSTAB solver along with better convergence behaviour.
Enhancement of Mechanical Engineering Education With Additive Manufacturing Projects
Authors: Billings Christopher , Siddique Zahed , Liu Yingtao
Published: February 2021

This paper presents an undergraduate research project developed to enhance mechanical engineering education at the University of Oklahoma. Selective Laser Sintering (SLS) is a promising additive manufacturing method for high-temperature materials with high spatial resolution and surface quality. As one of the most capable engineering-grade thermoplastics, polyether ketone (PEEK) can be used in additive manufacturing due to its elevated working temperature. This printer will use multiple heat zones, adjustable layer height, and a controlled hopper system to allow the user to fine-tune every print.

In this paper, students are required to analyze the technical challenges of SLS based 3D printing technology. Using three separate controlled heat zones, the user will be able to hold the part above its glass transition temperature until the entire part finishes, therefore, annealing it in the process. This will additionally allow for testing and documentation of the effect of heat during preheating, pre-sintering, and post sintering. These features in a small-scale machine will allow thorough documentation of how controlled heated environments can alter the physical properties of a 3D printed part. Using a full steel platform with CNC machined parts and an off the shelf laser, the cost will be reduced to under ten thousand dollars. This undergraduate project to design an SLS based 3D printer provide a unique opportunity for students to fully understand the challenges of SLS manufacturing and gain experience in developing a complex 3D printing system.
Popping Elbow Joint: Effects and Results
Authors: Salman Muhamad , Hadjimirzaei Anaheeta , Reed Sammy
Published: February 2021

The aim of this research project is to study patients with elbow instability and design a brace that will help with the injury. The idea for this research project was presented by one of the research partners who has suffered from elbow instability for 10 years. Elbow instability is a rare condition that is mostly unspoken about. Many live with this condition without knowing it exists or simply ignoring it. But the effects of this injury are painful and permanent, making it harder to perform daily tasks using the arm. This research will provide data for a possible medical device to help reduce forces on the elbow joint and help reduce pain from elbow instability. To better analyze data for this injury, the elbow joint must be placed under a force test. Two participants volunteered to perform the test by lifting a series of weights. Data for the Electromyograms (EMG) was then collected using only the Trigno Wireless Biofeedback System, placed above the humerus near elbow joint where the injury is most common. Another aspect of this research was to better understand the popping of the elbow joint. A 3D model of the elbow joint was then printed and further analyzed. All gathered data and analytics are used to study how a medical brace could possibly help with patients’ elbow instability. The final goal for this research will be to design and create a brace that will alleviate pain caused by elbow instability in the patient. The brace will allow users to endure repeated popping of the elbow joint while muscles are contracted and relaxed.
Calculation and Variation of Thermoelectric Properties of Phase Transition Materials
Authors: Vallin Micah P. , Zhang Richard Z.
Published: February 2021

Thermoelectric materials are defined as materials which can convert heat into electrical energy. Thermoelectric materials are often used for applications such as power generation or refrigeration. Because of the applications for thermoelectric materials, it is important to understand the electrical-to-thermal coupling behavior of such materials. The thermoelectric materials simulated are 2D film configurations of Tin Selenide (SnSe). Using the derivations for non-equilibrium electron-phonon dynamics as well as obtaining the phonon dispersions, second-order and third-order elastic constants, the thermoelectric properties can be calculated. For the purposes of this paper, the correlation of thermoelectric properties such as thermopwer, thermal conductivitty, and thermoelectric figure of merit with parameters such as the characteristic length of the 2D material as well as the applied voltages of 0 V/m, 10,000 V/m, and 20,000 V/m over the 2D material. Furthermore, an analysis on the effect of strain on the thermoelectric properties of SnSe is conducted.
Simulation of Ion Current in Oxyfuel Flame Subject to an Electric Field
Authors: Xu Kemu , Untaroiu Alexandrina , Martin Christopher
Published: February 2021

This paper presents a computational model to study ion and electron transportation and current-voltage characteristics inside a methane-oxygen flame. A commercial software is used to develop the model by splitting the simulation into the combustion and electrochemical transportation parts. A laboratory experiment is used to compare the results from the model. The initial and boundary conditions represented in the model are similar to the experimental conditions in the laboratory experiment.

In the combustion part, the general GRI3.0 mechanism plus three additional ionization reactions are applied and results are then used as input into the electrochemical transportation part. A particular inspection line is created to analyze the results of the electrochemical transportation part. Ion, electron number density, and current density are studied along the interval from −40V to 40V electric potential. The ions are heavier and more difficult to move than electrons. The results show that at both torch and work surfaces charged sheaths are formed and cause three different regions of current-voltage relations.
Microwave-Induced Thermoacoustic Compressive Imaging With Metamaterial Coding
Authors: Mao Xu , Liu Chang , Heredia-Juesas Juan , Martinez-Lorenzo Jose Angel
Published: February 2021

The microwave-induced thermoacoustic (TA) sensing has been proven to promise a great potential in clinical and biomedical applications. This novel technology has also been explored to boost its use in subsurface geophysical applications. A conventional TA sensing system, however, is greatly limited by either a slow scan or a dramatical cost, and making infeasible the real-time monitoring when covering large domains. One remarkable solution of such issues is to design a compressive sensing (CS)-based TA system, with the aim of reducing the sampling intensity necessary to high resolution imaging. Specifically, to favor the demand for CS, this work studies the appropriateness of metamaterial (MM) resonators and proposes a MM linear array-coded TA system to randomize the transmitted acoustics waves. To prove the efficacy, images obtained from both of the proposed TA system and the conventional TA system without coding are assessed and compared. Under the same scenario, the MM-coded TA system shows higher imaging capabilities and a better performance when using a much-limited amount of measurements or in noisy enviornments. This method opens the door for a fast scan of the geological imaging and the real-time monitoring of the underground flow.