bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modeling and Simulation of Thermal Energy Storage for Solar Energy Utilization
Authors: Alnaimat Fadi , Mathew Bobby , I. Mourad Abdel-Hamid , Al Omari S.-A. B. 
Published: January 2020

Abstract
A significant research has been done on the enhancement of thermal energy storage systems. This article details the numerical study conducted to understand the heat transfer and fluid flow characteristics of a concentric thermal energy storage subjected to different heat transfer fluid (HTF) velocities. Water is used as the working heat transfer fluid. The influence of flow parameter primarily the HTF velocity is studied in this article. Studies are conducted for concentric thermal energy storage diameter of 25 mm, and 10 mm inner diameter of concentric pipe, 200 mm length, and HTF velocity of 0.02, 0.1, 0.3, 0.5 m/s. It is found that the utilization of fins improves the heat transfer in tube in tank thermal storage system. Computational fluid dynamics (CFD) enables a more detailed study of the phase change thermal characteristics.
Scaling Behavior in Electrohydrodynamic Jetting of Polymeric Solutions
Authors: Singh Abhishek K. , Dubey Kaushlendra , Srivastava Rajiv K. , Bahga Supreet Singh 
Published: January 2020

Abstract
An electrohydrodynamic (EHD) jet forms when a leaky-dielectric liquid issuing out of a needle is accelerated and stretched by electrostatic forces. Stability and scaling behavior of the EHD jet of polymeric solutions depend on electrostatics, fluid mechanics and rheology of the liquid. While EHD jetting of Newtonian liquids have been described in the literature, the effect of non-Newtonian rheology on EHD jetting is still not well-understood. Therefore, we present a detailed experimental investigation of the stability and scaling behavior of EHD jets of polymeric solutions that exhibit non-Newtonian flow behavior. The stability of cone-jet was analyzed by varying flow rate, electric field and polymer concentration. Experiments were performed for polymeric solutions of polycaprolactone (PCL) dissolved in acetic acid. Our experiments show that non-Newtonian viscoelastic behavior can significantly alter the stability characteristics of the EHD jet. We have found that increase of elasticity of polymeric solutions results in enhanced jet stability. Finally, we present the dependence of experimentally measured diameter dj of the EHD jet on the flow rate Q. Experimentally measured diameter of the EHD jet scales as dj ∼ Q0.65 for both Newtonian and non-Newtonian viscoelastic liquids, which can be attributed to dominant inertia forces in our experiment.
Production and Analytics of a Multi-Linked Robotic System
Authors: Rykkje Thorstein R. , Gulbrandsen Eystein , Hettervik Andreas Fosså , Kvalvik Morten , Gangstad Daniel , Tislevoll Torgeir Oliver , Aasebø Stefan , Osberg Daniel Vatle 
Published: January 2020

Abstract
This paper extends research into flexible robotics through a collaborative, interdisciplinary senior design project. This paper deploys the Moving Frame Method (MFM) to analyze the motion of a relatively high multi-link system, driven by internal servo engines. The MFM describes the dynamics of the system and enables the construction of a general algorithm for the equations of motion. Lie group theory and Cartan’s moving frames are the foundation of this new approach to engineering dynamics. This, together with a restriction on the variation of the angular velocity used in Hamilton’s principle, enables an effective way of extracting the equations of motion. The result is a dynamic 3D analytical model for the motion of a snake-like robotic system, that can take the physical sizes of the system and return the dynamic behavior. Furthermore, this project builds a snake-like robot driven by internal servo engines. The multi-linked robot will have a servo in each joint, enabling a three-dimensional movement. Finally, a test is performed to compare if the theory and the measurable real-time results match.
Stability Measures and Criteria for Autonomous Mobile Robotic Platforms: Analysis, Comparison and Numerical Evaluation
Authors: Nazem Tahmasebi Kaveh , Belotti Roberto , Vidoni Renato , Von Ellenrieder Karl 
Published: January 2020

Abstract
The tip-over instability of an autonomous mobile robot is a significant problem as it can diminish its maneuverability and increase the possibility of damaging the robot and its surrounding environment. For these reasons, it is important to define the stability margin and predict the edge of the tip-over instability considering different robot specifications and environmental conditions. Different stability measures have been developed to evaluate and analyze robot stability margins for diverse conditions. In this work, the Zero Moment Point, Energy Stability Margin, Force-Angle Stability Measure, and Mass-Moment Height Stability Measure methods are considered and applied to different mobile robot architectures including three-wheeled, four-wheeled (with rectangular and trapezoidal base surface) and articulated systems. The stability margins are discussed considering the four different stability criteria and evaluating the effect of a sloped surface. Then, the sensitivity of the tip-over instability in relation to the variation of the center of mass height as an important robot configuration parameter is evaluated. Finally, after a theoretical extension of the Force-Angle Stability and Mass-Moment Height stability measurement methods, the articulated mobile robot’s stability margin is considered and evaluated.
Numerical Investigation of Combined Sensible/Latent Heat Thermal Energy Storage With Supercritical Carbon Dioxide As Heat Transfer Fluid at 650°C
Authors: Osterman Kelly , Guillen Diego , Goswami D. Yogi 
Published: January 2020

Abstract
This paper numerically explores a high-temperature sensible-latent hybrid thermal energy storage system designed to store heat with output temperatures stabilized at approximately 550–600 °C for direct coupling with supercritical carbon dioxide (sCO2) power cycles operating at their design point. sCO2 and dry air at 25 MPa are used as heat transfer fluid (HTF) in a packed bed storage system that combines rocks as sensible heat storage and AlSi12 as latent heat storage. The base model using dry air at atmospheric pressure is compared to similar work done at ETH Zurich; the model is then extended for use with sCO2 to compare the performance of air and sCO2 at similar volumetric flow rates. It was found that sCO2 is capable of storing a significantly larger amount of energy (∼40 kWh) in the same time period as the air system (∼19 kWh), and can discharge that energy much quicker (1.5 hours compared to 4 hours). However, in order to achieve similar degrees of temperature stabilization, the total height of PCM had to be increased significantly, from 9 cm to 45 cm or more.
Three-Dimensional Modeling of Reduced Material Properties in Ceramics With Added Porosity
Authors: Wimmer Stephanie A. , DeGiorgi Virginia G. , Gorzkowski Edward P. , Ryou Heonjune 
Published: January 2020

Abstract
Manufacturing methods to create ceramic coatings with tailored thermal conductivity are crucial to the development of thermal protection systems for many components including turbine blades in high temperature engines. A designed microstructure of grains, pores, and other defects can reduce the thermal conductivity of the ceramic. However, the same microstructure characteristics can reduce mechanical properties to the point of failure. This work is part of a larger program with the goal of optimizing ceramic coating microstructure for thermal protection while retaining sufficient mechanical strength for the intended application. Processing parameters have been examined to identify methods designed to maintain a nano-sized grain structure of yttria-stabilized zirconia while controlling the added porosity with a specific shape and size. In this paper computational modeling is used to evaluate the effects of porosity on coating performance, both thermal and structural. Coating porosity is incorporated in the computational models by randomly placing empty spaces or defects in the shape of spherical voids, oblate pores, or penny cracks. In addition to computational modeling, prototype coatings are developed in the laboratory with specific porosity. The size and orientation of defects in the computational modeling effort are statistically generated to match experiments. The locations of the defects are totally random. Finite element models are created which include various levels of porosity to calculate effective thermal and mechanical properties. Comparisons are made between three-dimensional finite-element simulations and measured data. The influences of pore size as well as three dimensional computational modeling artifacts are examined.
Non-Invasive Tracking of Micro-Scale Microrobot Using Photoacoustic Imaging
Authors: Yan Yan , Carey Zachary , Mehrmohammadi Mohammad , Jing Wuming 
Published: January 2020

Abstract
This paper presents the innovative integration of both frontier submillimeter magnetic microrobot and integrated ultrasound and photoacoustic (USPA) imaging. The integrative technique will allow for potential real non-invasive microrobot operation in deep biological tissue for biomedical applications. In this study, the magnetic microrobot prototypes are fabricated in series of different sizes through patterning SU-8 photoresist mixed with nickel particles. In order for proof-of-concept, the magnetic microrobot is actuated by a static magnetic field, which is produced by a multiple magnet cone array. As mimicking the opaque biological environment, the magnetic microrobot is placed in a fluid environment bounded by a non-transparent phantom. The USPA imaging system consists of a laser system to illuminate working space and an ultrasound system to receive the acoustic signal generated by imaging object due to photonic signal absorption. The experimental tests prove that the USPA imaging protocol can detect single microrobot smaller than 100 μm through the 15 mm thick opaque phantom. The imaging test has been accomplished both statically and in a motion of approximately 2.0 mm/s. Further investigation of this concept will focus on the collaboration of photoacoustic imaging and magnetic manipulation of microrobot under real biological fluid media.
Effect of Particle Breakage on Explosibility of Coal/Rock Dust Mixtures due to Dispersion in 20-L Chambers
Authors: Rayyan Naseem , Perera Inoka E. 
Published: January 2020

Abstract
Research has shown that particle size has a significant impact on the explosibility of coal dust/rock dust mixtures. Previous explosion studies conducted using the U.S. Bureau of Mines’ (BOM) 20-L explosion chamber tend to show a difference in the amount of inerting material needed to prevent an explosion when compared to the 20-L Siwek chamber. To reconcile these differences, samples were comparatively tested in the historic BOM 20-L chamber and the new NIOSH 20-L Siwek chamber with an emphasis on particle breakage. Rock dust and coal dust samples were dispersed in the chambers without ignitors and their specific surface areas were compared to the undispersed specific surface areas in order to quantify the breakage. Then, rock dust and coal dust mixtures were prepared, dispersed using the Siwek chamber, collected and tested for explosibility in the BOM 20-L chamber to see if the severe particle breakage in the Siwek chamber would influence the inerting limits of the BOM chamber. Results indicate that the particle breakage of friable brittle materials during explosion testing should be considered when evaluating the explosion risks in the process industries.
Experimental and Numerical Investigations of Pressure Loss and 3-D Flow Separations in a Linear Compressor Cascade
Authors: El-Shahat Saeed A. , El-Batsh Hesham M. , Attia Ali M. A. , Li Guojun , Fu Lei 
Published: January 2020

Abstract
Flow separation is a major parameter affecting the compressor performance. It reduces the compressor efficiency, limits static pressure rise capability and contributes to instability in compressors. In applied research, there is a lack of understanding of the nature and mechanism of the three-dimensional (3-D) flow separation in the axial compressor especially on the juncture of the endwall and blade corner region. In the present study, the 3-D flow field in an axial compressor cascade has been studied experimentally as well as numerically.
For the experimental study part, a linear compressor cascade has been installed in an open loop wind tunnel. The experimental data was acquired for a Reynolds number Rec = 2.98 × 105 based on the blade chord and the inlet flow conditions. The total pressure loss progress through the blade passage has been measured by using calibrated five and seven-hole pressure probes connected to ATX sensor module data acquisition system. The static pressure distribution on the endwall has been measured employing static pressure taps connected to digital micromanometers. To investigate the loss mechanism through the cascade, the total pressure loss coefficient has been calculated from the measured data.
The computational fluid dynamics (CFD) study of the flow field was performed to gain a better understanding of the flow features. Two turbulence models, Spalart-Allmaras (S-A) and shear stress transport SST (k-ω) were used. From both parts of study, the flow field development and total pressure loss progress through the cascade have been investigated and compared. Moreover, the received data demonstrated a good agreement between the experimental and computational results. The predicted flow streamlines by numerical calculations showed regions characterized by flow separation and recirculation zones that could be used to enhance the understanding of the loss mechanism in compressor cascades. All measurements taken by 5-hole and 7-hole pressure probes have been analyzed and compared. It was found that their readings were almost the same and there are no excellences for using 7-hole probe. Furthermore S-A turbulence model calculations showed more consistencies with experimental results than SST (k-ω) model.
Effect of Processing Technique on the Mechanical Properties of a Functionalized Superhydrophobic Silane
Authors: Baruwa Akinsanya Damilare , Akinlabi Esther Titilayo , Oladijo O. P. , Dutta-Majumdar Jyotsna , Krishna Shree 
Published: January 2020

Abstract
The need to test for the durability and capability of a coating before being subjected to service is highly important for engineering applications. Ultra-low indentation of nano-hardness and nano-scratch are valuable methods of measuring durability and near-surface mechanical properties of thin films. AISI 304 stainless steel was coated with Repellix superhydrophobic coating using chemical vapor deposition (CVD) and atomic layer deposition (ALD) techniques at constant processing parameters. The deposited films were characterized through nanoindentation, nanoscratch, and water contact angle to establish the effect of coating technique on the mechanical properties of the thin films. The results established that the ALD deposition technique has better hardness but less wear resistance when compared to the sample produced using the CVD method. ALD also showed to have a lower contact angle in comparison with a coating deposited by CVD. Overall, it is expected that the substrate coated by CVD would outperform samples produced via ALD as regards to typical applications where good wear and corrosion resistance are required.
Recycling Lithium-Ion Battery: Mechanical Separation of Mixed Cathode Active Materials
Authors: Al-Shammari Hammad , Esmaeeli Roja , Aliniagerdroudbari Haniph , Alhadri Muapper , Hashemi Seyed Reza , Zarrin Hadis , Farhad Siamak 
Published: January 2020

Abstract
Lithium-ion batteries (LIBs) have driven the industry of rechargeable batteries in recent years due to their advantages such as high energy and power density and relatively long lifespan. Nevertheless, the dispose of spent LIBs has harmful impacts on the environment which needs to be addressed by recycling LIBs. However, none of the currently developed recycling processes is economical. The physical recycling process of LIBs may be economical if the cathode active materials can be separated, regenerated, and reused to make new LIBs. However, the first barrier for regeneration and reusing is the separation of different types of spent cathode active materials in the filter cake that are mixed with each other and come in the form of very fine powders with various sizes (&lt; 30 μm) from the physical recycling process. The aim of this study is to separate the mixture of cathode active materials by adopting Stokes’ law. The focus will be only on mechanical separation with no thermal or chemical separation methods. For the validation, an experiment was designed and successfully performed where different types of spent cathode materials (e.g., LiCoO2, LiFePO4, and LiMn2O4) were separated from the spent anode materials (e.g., graphite) with high efficiency and reasonable time.
A Novel Ferrofluid-Based Valve-Less Pump
Authors: Michelson Trevor , Rudnick Joshua , Baxter Joshua , Rashidi Reza 
Published: January 2020

Abstract
This paper demonstrates the development of a fluidic pump, magnetically actuated by a ferrofluid through a circular channel. The pump has a rotary design with a tangential input and output. It is designed to house a magnet to create a ferrofluid plug in one place between the inlet and outlet. There are two magnets outside of the housing attached to a rotating apparatus that move the ferrofluid around. The ferrofluid then moves around the channel, taking in and moving water through the channel towards the outlet. The pump was fabricated using a 3D printing technique. The pump was tested at three different configurations at a zero back pressure including single small moving magnet, double small moving magnet and single large moving magnet. The volumetric flow rate was measured at different rotational speeds from 9.375 rpm to 25 rpm. The highest average flow rate measured was 0.8 ml/min at 25 rpm with a single large magnet. This pump can be used for a circuit board cooling device; the pump would deliver a coolant through miniature tubes to cool the system.
Influence of Blending Hydrogen and Biogas Into Natural Gas on the Combustion Performance of a Tankless Water Heater
Authors: Zhao Yan , Morales David , McDonell Vincent 
Published: January 2020

Abstract
Utilizing renewable gases including biogas and renewable hydrogen instead of natural gas helps reduce greenhouse gases from fossil fuel combustion. Due to the fuel property variation, it is not practical to replace pipeline natural gas with these renewable fuels while still keeping the combustion devices at its designed operating condition. Therefore, this study mixes renewable hydrogen and simulated biogas into pipeline natural gas and investigates the combustion performance of a commercial tankless water heater. Up to around 10 vol% carbon dioxide and 20 vol% hydrogen are mixed into natural gas, then the mixtures are supplied to the water heater. Appliance performance such as operability, emissions (CO, UHC, NO, NO2, N2O, NH3) and efficiency are examined. The feasibility of injecting renewable gases into the existing natural gas infrastructure is evaluated from the perspective of the representative tankless water heater performance. The results show a positive sign for mixing hydrogen into pipeline natural gas, due to the small variation of the water heater emissions and an increase of the efficiency.
2D and 3D Stability of Cavity Flows in High Mach Number Regimes
Authors: Doshi Parshwanath S. , Ranjan Rajesh , Gaitonde Datta V. 
Published: January 2020

Abstract
The stability characteristics of an open cavity flow at very high Mach number are examined with BiGlobal stability analysis based on the eigenvalues of the linearized Navier-Stokes equations. During linearization, all possible first-order terms are retained without any approximation, with particular emphasis on extracting the effects of compressibility on the flowfield. The method leverages sparse linear algebra and the implicitly restarted shift-invert Arnoldi algorithm to extract eigenvalues of practical physical consequence. The stability dynamics of cavity flows at four Mach numbers between 1.4 and 4 are considered at a Reynolds number of 502. The basic states are obtained through Large Eddy Simulation (LES). Frequency results from the stability analysis show good agreement when compared to the theoretical values using Rossiter’s formula. An examination of the stability modes reveals that the shear layer is increasingly decoupled from the cavity as the Mach number is increased. Additionally, the outer lobes of the Rossiter modes are observed to get stretched and tilted in the direction of the freestream. Future efforts will extend the present analysis to examine current and potential cavity flame holder configurations, which often have downstream walls inclined to the vertical.
Advanced Calculation Flutter Procedure Developed for Ultra-Long Last Stage Blades for Steam Turbines
Authors: Slama Vaclav , Rudas Bartolomej , Macalka Ales , Ira Jiri , Zivny Antonin 
Published: January 2020

Abstract
An advanced in-house procedure, which is based on a commercial numerical code, to predict a potential danger of unstalled flutter has been developed and validated. This procedure using a one way decoupled method and a full-scale time-marching 3D viscous model in order to obtain the solution of the Unsteady Reynolds-Averaged Navier-Stokes equations in the time domain thus calculate an aerodynamic work and a damping ratio is used as an essential tool for developing ultra-long last stage rotor blades in low pressure turbine parts for modern steam turbines with a large operating range and an enhanced efficiency. An example is shown on a development of the last stage blade for high backpressures.
Effect of Graphene Nanoplatelets Incorporation on Microstructural and Tribological Properties of Aluminium Metal Matrix Composites
Authors: Sharma Ankit , Priyadarshini Amrita , Sujith Ravindran , Subrahmanyam M. V. Sankara , Thomas P. Alen , Gupta Amit Kumar 
Published: January 2020

Abstract
Aluminium metal matrix composites exhibiting superior mechanical and tribological properties have gained immense interest in recent years. These comosites are finding broad applications in the fields of automotive, aerospace, military and marine. Graphene Nanoplatelets (GNPs), as reinforcement in composites, have become a prime focus because of its exceptional characteristic properties. In the present study, GNPs are dispersed into the aluminium alloy as reinforcements by using stir casting method. To ensure proper dispersion, sintered pellets of aluminium mixed with GNPs are added to the molten metal. The dispersion of the GNPs and the microstructural changes due to the addition of GNPs are observed using Scanning Electron Microscopy (SEM) and elemental mapping. Vickers hardness tester is used to measure hardness of these samples. To compare the tribological properties of Al/GNP composite as well as pure alumimum samples, pin-on-disc experiments are conducted for a specific combination of sliding speed and sliding distance at different loading conditions. The weight loss, wear rate and coefficient of friction are measured and favourable effects of GNPs on tribological properties of Al/GNP composite are discussed. In addition, the wear mechanism has been understood in detail by conducting microstructural studies of the worn surfaces using SEM and Energy Dispersive Spectroscopy. It is observed that the Vickers hardness of the composite increased to a maximum of 25% while coefficient of friction decreased to a minimum of 26% for Al/GNP composite.