bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preliminary Results of Microwave Induced Thermoacoustics Imaging in Geological Media
Authors: Liu Chang , Mao Xu , Heredia Juesas Juan , Molaei Ali , Martinez-Lorenzo Jose Angel 
Published: January 2020

Abstract
Seismic and electromagnetic imaging modalities are conventionally used in subsurface situational awareness applications. These modalities have been very effective at characterizing the geological media in terms of its constitutive mechanical properties such as density and compressibility, as well as electromagnetic properties such as electric conductivity, permeability, and permittivity. In order to enhance these imaging capabilities, a Thermoacoustic (TA) imaging system is used in this work. TA imaging relies on the coupling of mechanical and electromagnetic waves through a thermodynamic process, and it has the potential to reconstruct thermodynamic constitutive properties such as volumetric expansion coefficient and heat capacity. TA imaging has been mostly used in biological applications; this is due to the low signal-to-noise ratio that can be created with this physical mechanism. This work is aimed at addressing such limitation and exploring the use of TA imaging in geophysical applications. Conventionally, a short microwave pulse excitation is used to create the TA wave; so that the stress confinement condition is met while providing high resolution images. This approach requires the use of expensive high power amplifiers to create a detectable TA signal. This limitation can be addressed by using a frequency-modulated continuous wave (FMCW) excitation, which has been recently proposed as a suitable mechanism to enhance the signal-to-noise ratio of the TA signal generated for a given peak power constrain. This paper discusses and compares both pulsed and FMCW TA imaging in geological media. Preliminary experimental results show the efficacy of this approach to image a rock immersed in an oil bath; thus paving the way towards its future use for subsurface sensing and imaging of fluid flow and transport in porous media.
Multidisciplinary Problem Based Learning: Venipuncture Practice Arm Research
Authors: Doan Phuong , Gomez Connie 
Published: January 2020

Abstract
Community colleges need more avenues for undergraduate research during their first two years in higher education but face challenges to building robust research namely the limited time frame students are at a community college and the limited resources for research. To maximize the limited resources and the educational experience for the students, multidisciplinary projects within the community college environment provide both engineering and science students with research opportunities that fit the schedule of a working student, allow interaction between disciplines, provide team-based environments, and foster life-long learning. This paper describes 1) a multidisciplinary project for honor chemistry and engineering students; introduction to engineering students and engineering graphics students in the development of a venipuncture practice arm for nursing students practicing venipuncture techniques in the simulation lab. 2) the institutional supports that promote the development of collaborative and multidisciplinary research projects and 3) recommendations for other community colleges interested in developing multidisciplinary research opportunities throughout their engineering and science curriculums.
Investigation of Sub Synchronous Vibration of Very High Speed Turbocharger Semi-Floating Bearing System: Prediction vs Test
Authors: R. Vengala Prasanth , Chandrasekaran Lokesh , Selvaraj Praveen Kumar , Arthanarisamy Subramani D. 
Published: January 2020

Abstract
Automotive engines are facing increased design focus towards downsizing, higher performance and lower emissions, in the process, challenging turbocharger (TC) technology to their limits. Downsizing of the engine needs smaller compressor and turbine wheels to achieve the critical flow requirements that leads to very high TC operating speeds of more 300k rpm. In general, TC rotor is most commonly supported by hydrodynamic fully floating (RFRB) or semi-floating bearing (SFRB) systems. For such high-speed applications, SFRB could be preferred bearing system where inner and outer bearing clearances act as a plain journal bearing and a squeeze film damper. These hydrodynamic bearings, exhibit non-linear oil whirl/whip phenomena in the inner bearing that leads to higher sub-synchronous vibration and overall deflection of the shaft. Sub-synchronous behavior of the SFRB is evaluated both numerically and experimentally (hot gas stand) for two design variants and results are published in this paper.
TCs were run up in hot gas stand and were recorded using NVH Data Acquisition System (DAQ) with frequency analyzers and eddy current displacement sensors. In numerical simulations, multi-body dynamics (MBD) of flexible rotor and housing structures are coupled with elasto-hydrodynamics (EHD) of the inner and outer oil films. The energy equation is considered for calculation of oil film temperature in EHD using thermal boundary condition obtained from 3D FE simulation. Detailed numerical investigation was conducted using EHD joint definitions in the above bearing system. Good agreement was obtained between test and prediction, and finer source characterization was achieved using simulation.
Wind Energy Harnessing System for Low and High Wind Speeds
Authors: Rashidi Majid , Kadambi Jaikrishnan R. , Ke Renjie 
Published: January 2020

Abstract
This work presents the design and analysis of a novel wind energy harnessing system that makes use of wind defecting structures to increase the ambient wind speed at geographic locations with relatively low wind speed. The system however reacts to highspeed wind conditions by altering the profile of the wind defecting structure in order to eliminate wind speed amplification attribute of the system, thereby protecting the wind turbine assembly at high speed wind conditions. Although increasing the wind speed is advantageous at geographic locations that the wind speed is typically low; however, from times to time, there could be sustained high-speed wind conditions at the same locations that may damage the wind turbine systems that take advantage of the wind defecting structures. The present work disclosed a wind deflecting structure formed by at least two sail-like partial cylindrical structures that are supported atop of a tower-like foundation in a symmetric arrangement, where one or more wind turbines can be installed in the space between the two partial cylinders. The two partial cylinders, each substantially in form a quarter cylinder is made of plurality of parallel ribbed-like bars, hereafter referred to as “bars” with a flexible thin material that are mechanically supported by the bars. The bars are oriented in a direction perpendicular to the ground; allowing the wing deflecting structures to accept horizonal axis or vertical axis turbines in the space between them. The function of the bars is to allow the thin material, attached to them, to assume a curved configuration substantially in the form of a quarter cylinder. The apparatus is equipped with wind speed monitoring devices, and power source and power transmission means, such as cable-pulleys, chain-sprockets, gears, or mechanical linkages that all work in concert to deploy or stow the thin material along the vertical rods depending to the magnitude of the prevailing wind speed. Preliminary computational fluid dynamics analyses have shown that the wind deflecting structure proposed here in amplifies the wind speed by a factor of 1.65.
Experimental Investigation of PolyJet 3D Printing Process: Effects of Orientation and Layer Thickness on Thermal Glass Transition Temperature
Authors: Sanders Jackson , Wei Xingjian , Pei Zhijian 
Published: January 2020

Abstract
The J750 PolyJet printer is the newest model of full-color and multi-material 3D printer from Stratasys. Currently, limited information is available about the effects of control factors on thermal glass transition temperature of parts printed by this printer. In this study, the effects of two control factors, printing orientation and layer thickness, on the thermal glass transition temperature (Tg) are investigated. The results suggest that both control factors significantly affect Tg. Specifically, samples printed using the high mix mode have higher elastic moduli than those printed using high quality mode. Larger values of elastic moduli directly lead to a higher thermal glass transition temperature, making the material more effective under relatively extreme temperatures and duress. These results would be valuable to researchers and practitioners who use the Polyjet 3D printer.
Osteoporotic Bone Augmentation Utilizing Curved Pattern of PMMA Injection: A Combined Finite Element and Optimization Investigation
Authors: Farvardin Amirhossein , Armand Mehran 
Published: January 2020

Abstract
A potential effective treatment for prevention of osteoporotic hip fractures is augmentation of the mechanical properties of the femur by injecting it with Polymethyl-Methacrylate (PMMA). We have previously developed a preoperative planning workstation to optimize the pattern of cement injection. In this planning paradigm, injections occur on a straight line limiting the overall match between the optimal and injected volumes of the cement. In addition, new advancements in drilling techniques has made it possible to plan and drill the bone based on a curved trajectory. In this study, we introduced a methodology to find the optimal drill path for PMMA injection. With the aid of Finite Element (FE) and hydrodynamic simulations, the effectiveness of the proposed approach was evaluated. Results showed that with an average injection of 7.2 ml, the proposed method can increase the yield load of the femur by 69%. Future works involve experimental validation of this method in cadaveric studies.
Residential Heating System Control for Future Electric Power Grid Services Using Minimal Measurements
Authors: Brambley Michael R. , Lian Jianming 
Published: January 2020

Abstract
The study presented focuses on control of central electric resistance heating (often referred to as electric furnaces) in a manner to meet a specified target reduction in average electric power demand over 5-minute utility verification periods. The paper describes a supervisory control method that uses a small number of sensed points to meet these target power demand reductions while ensuring that indoor temperature is maintained within a comfortable range. Testing of the control method is performed in two identical test homes with the control methodology augmented to account for practical complexities in the operation of the heating system equipment (e.g., minimum-off [lock-out] time, response activation delay, and data latency). The test homes, equipment in them, data collection apparatus, and control platform are described as well as results of the testing.
The analysis of results shows the potential for control of electric heating systems to provide demand response as well as some limitations when used alone without coordinated control with other end-use equipment and appliances. Discussion of results includes a brief introduction to a method for coordinated control of multiple appliances in homes and identification of potential future research to realize the underlying vision of homes providing services to the power grid.
A Computational Fluid Dynamics (CFD) Study of Pneumatic Atomization in Aerosol Jet Printing (AJP) Process
Authors: Salary Roozbeh (Ross) , Lombardi Jack P. , Weerawarne Darshana L. , Rao Prahalad K. , Poliks Mark D. 
Published: January 2020

Abstract
Aerosol jet printing (AJP) is a direct-write additive manufacturing method, which has been utilized particularly for the fabrication of flexible and hybrid electronics (FHE). In spite of the advantages of AJP — e.g., high-resolution material deposition on nonplanar surfaces and accommodation of a wide renege of ink viscosity — AJP inherently is a complex process, prone to nonlinear process changes. Consequently, real-time process monitoring and control (with an understanding of the physics behind aerosol generation and transport) are inevitable. The overarching goal of this work is to establish a physics-based framework for process monitoring and closed-loop control (for correction) in AJP. In pursuit of this goal, the objective is to forward a CFD model to explain the underlying physical phenomena behind aerosol nebulization in AJP. To realize this objective, a 3D compressible, turbulent multi-phase flow CFD model is forwarded. The geometry of the pneumatic atomizer is modeled based on X-ray computed tomography (CT) imaging. The boundary conditions of the problem are defined based on experimental observations. The outcome of this study paves the way for understanding the complex mechanisms of aerosol generation in AJP and also design of efficient atomizers.
Improving the Performance of Centrifugal Pumps in Serial and Parallel Configurations Using Digital Twins
Authors: Carrillo Peña Andrés L. , Eugenio Barroso Jeffer S. , Martínez Vesga Alberto A. , Roa Prada Sebastián , Ardila Acuña Victor A. 
Published: January 2020

Abstract
Centrifugal pumps are devices commonly used in countless industrial and residential applications, from water supply systems to oil and gas processing plants. These rotatory hydraulic machines have a strong impact on the energy consumption of industry worldwide, not only because of their vast amount but also because of their continuous operation. Therefore, developing techniques to improve the efficiency of pumping systems is of great help to make communities and industrial activity more sustainable. The overall performance of these pieces of machinery cannot be fully predicted by means of analytical procedures due to the complexity of the fluid flow phenomena that occurs in their interior, so it is common practice to resort to alternate modeling techniques, such as computer aided numerical analysis, which can predict the performance of a pump, given its CAD computer model. However, the performance of an actual centrifugal pump may deviate from its ideal behavior due to multiple causing factors which may alter the performance curves given by the manufacturers in the corresponding data sheets. The discrepancies between the real and the simulated responses of centrifugal pumps demand for better modeling and simulation techniques to improve the design of more efficient pumping systems. Digital twins have the ability to bring the simulation environment closer to reality, by replicating the behavior of the physical system in a simulation environment with the support of experimental data. The digital twin of a multiple pumps system with serial and parallel configurations was developed, based on two identical industrial centrifugal pumps available in the laboratory. Experimental data was collected to calibrate the digital twin system so that the simulated system can predict the response under changing operating conditions. The simulation environment was developed with the assistance of a commercial Computational Fluid Dynamics computer program. After validating the behavior of the virtual components, with respect to the behavior of their actual counterparts, tests were carried out to predict the behavior of the pumping system in case of downstream disturbances which can affect the operating point of the overall pumping system and its corresponding efficiency. The development of the digital twin for the pumping system allowed visualizing how the pumps connected in series or in parallel can be maneuvered to adjust its operating conditions to achieve higher efficiency operating conditions in response to changes in the conditions downstream in the pipeline.
Wheel Slip Regulation for Heavy Commercial Road Vehicles Using Model Predictive Control Subsumed With Auto-Regressive Time-Series Modelling
Authors: Gaurkar Pavel Vijay , Challa Akhil , Subramanian Shankar C. , Vivekanandan Gunasekaran , Sivaram Sriram 
Published: January 2020

Abstract
Wheel Slip Regulation (WSR) is one of the Active Vehicle Safety Systems (AVSSs) for maintaining vehicle stability and maneuverability during emergency braking An approach for wheel slip prediction is proposed in this paper, which involves Auto-Regressive (AR) Time-Series modelling of longitudinal vehicle acceleration. This technique allows the usage of linear longitudinal vehicle dynamics for wheel slip estimation. A wheel slip prediction model was developed considering measurements from accelerometer and wheel speed sensor. This modified the Model Predictive Control (MPC) formulation to a univariate control input problem, involving braking torque. The objective function was devised for solving a least-squares reference tracking problem. An analytical solution for the MPC optimization problem was derived and implemented towards WSR. The proposed framework was programmed in MATLAB Simulink® and co-simulated with IPG TruckMaker® (a vehicle dynamic simulation software). The algorithm was tested in a Hardware-in-Loop (HiL) setup consisting of a pneumatic air brake system interfaced with IPG TruckMaker®. Open loop studies from HiL led to the inclusion of Kalman filter for estimate tuning and PID inner loop control for brake pressure transients, which improved wheel slip regulation.
Verification and Validation of Droplet Freezing for Convective Boundary Condition Using Matched Asymptotic Perturbation Method and Computational Fluid Dynamics
Authors: Akhtar Saad , Xu Minghan , Sasmito Agus 
Published: January 2020

Abstract
Droplet freezing has been a subject of several studies encompassing numerous applications such as food processing, spray freeze drying, ice accretion on the aircrafts and low temperature biological applications. The literature is rife with a comprehensive analytical and numerical treatment of the classical Stefan problem. There is a need, however, to address the development of accurate solutions for the two-phase Stefan problem where the initial droplet temperature is different than the freezing temperature of the droplet. A solution of such kind will allow for quick and convenient calculations for important geometric and operating parameters over a wide range.
This study presents a computational fluid dynamics model along with a perturbation series solution approximation developed for the temperature field and the interface motion. The semi-analytical results are compared with experimental results in the literature and are further complemented by a computational fluid dynamics study of a freezing droplet using enthalpy-porosity method. Preliminary results indicate a good agreement between experimental, numerical and perturbation series solutions.
Heat Transfer Characteristics of Various Gun Barrels Under Different Operating Conditions
Authors: Gadalla Mohamed , Jasim Muhammad , Ahmad Omar 
Published: January 2020

Abstract
The thermal stability parameter is an important parameter for predicting the lifespan of structures. In this paper, a two-dimensional transient heat transfer model of machine gun barrels undergoing continuous firing developed and analyzed for different geometries and thermal properties. The model for the transient thermal analysis is based on the forced convection heat transfer at the inner surface of the gun barrel. Finite element simulations were performed to predict the interior and exterior barrel temperature profiles and temperature contours after continuous firing process. The incomplete Cholesky Conjugate Gradient (ICCG) solver was adopted in solving unsymmetrical thermal transient analyses. The material thermal behavior studied for the basic circular cross section of gun barrels showed that the lowest inner wall temperature was for high rounds was achieved in steel barrels due to the rapid conducted and convective heat transfer to the environment. While the highest inner wall temperature was recorded for ceramic STK4 barrels and an increase of inner wall temperature by 17% was observed as compared to the typical case of circular cross section steel barrel. In general, a higher inner temperature in the gun barrel is undesirable and harm due to the possibility of reaching the cook-off scenario at earlier rounds. Results concluded that non-circular geometries with constrained cross section areas of typical case improve thermal management and the hexagonal geometry had the best thermal management and could provide more rounds for users. In addition, titanium barrels would have a weight drop of 41% while the overall barrel’s temperature increases by 49%.
Mechanical Design and Development of a Payload for Structural Health Monitoring Experiments on the International Space Station
Authors: MacNinch Douglas , Pacheco Daniel , Tandon Arjun , Bancroft Carl , Flores Isaac , Rue Matthew , Zagrai Andrei 
Published: January 2020

Abstract
This contribution reports design and development of a payload for structural health monitoring (SHM) experiments on the International Space Station (ISS). The payload was designed to operate in low earth orbit (LEO) environment and fit specifications of the Materials International Space Station Experiment (MISSE) module. In particular, LEO environmental factors such as a strong vacuum, thermal variations from −18°C to 60°C [1], and background radiation were considered. The payload is a rectangular multi-leveled structure which houses several SHM experiments, active sensors self-assessment, and electronic hardware with data storage and retrieval capabilities. SHM experiments include guided wave propagation in a metallic structure, monitoring of an imitated crack, assessment of a bolted joint, investigation of structural vibration via electromechanical impedance method, and acoustic emission monitoring. In addition, piezoelectric sensor self-assessment is realised using impedance diagnostics. It is anticipated that the payload will operate for one year in LEO and provide insights on the effect of space environment on SHM of future space vehicles during long-duration flights. This contribution focuses on mechanical design of the payload to support SHM experiment. Specific arrangement of payload elements and implementation of boundary conditions for SHM experiments are reported. Theoretical calculations and examples of SHM experimental data obtained in laboratory tests are presented and discussed in light of expected variations due to LEO environment. Measures to protect SHM hardware from harsh space environment are presented. Perspective applications of SHM as an integral component of future space systems are discussed.