bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development of Nano- and Micro-Fluids Using Magnetic Poly(Ionic Liquid)-Surfactant Complexes for Stimuli Response
Authors: Foley Kayla , Walters Keisha B. 
Published: September 2022

Abstract
Poly(ionic liquid) (PILs) are a rapidly growing subclass of polyelectrolyte which combines the diverse functionality of ionic liquids with the mechanical integrity, processability, and macromolecular design of polymeric systems. PIL properties are highly dependent on their counterion, which can be easily exchanged to tailor their material properties. Incorporation of metal halide counterions (FeCl4−, CoCl42−, etc.) into the PIL structure results in magnetically responsive metal-salt composites known as magnetic-PILs (MPILs). MPILs are predominately formed through electrostatic binding with anionic metal complexes typically resulting in paramagnetic properties at room temperature. The engineering properties and the ability to effectively apply these materials — is dependent on not only the chemical structure, but the nanostructure, co-materials, self-assembly, and stability in situ. In this study, a PIL copolymer, poly(acrylamide-co-diallyl dimethylammonium chloride), containing a quaternary ammonium PIL group and a comonomer capable of metal coordinating interactions, was combined with sodium dodecyl sulfate surfactant and cobalt (II) chloride salts to form magnetic polyelectrolyte-surfactant complexes. The self-assembly of these complexes was studied as a function of surfactant concentration through DLS, Zeta potential, and TEM characterizations. The magnetic properties were examined using AC susceptibility. The impact of the metal ion(s) and magnetic field on nanostructure alignment and film formation were also investigated through optical microscopy, GISAXS, and AFM imaging. Results were compared to well-defined ferrofluids as a comparative benchmark.
A Numerical Method and Study of Viscoelastic Droplet Breakup
Authors: Anderson Caroline , Kinzel Michael 
Published: September 2022

Abstract
This paper presents a comprehensive study of viscoelastic, droplet-breakup physics using multiphase computational fluids dynamics (CFD) based on the volume of fluid (VOF) method. The specific challenge and novelty are the overall outcome and methods used to explore viscoelastic breakup physics. In the context of VOF, the method approximates both viscous and elastic characteristics of the saliva with a function based on the Carreau-Yasuda (CY) model. The CY model is traditionally used for modeling blood flow and here is extended to approximate saliva. The foundation of the model couples the shear rate to drive both a variable viscosity and relaxation time. The results indicate a strong stabilizing effect of viscoelastic fluids that indicates that conventional breakup models provide a conservative estimate of droplet size as is relevant to the transmission pathogens.
Nusselt Number Dependence on Aspect Ratio and Rayleigh Number: A Numerical Study of Rayleigh-Benard Instability
Authors: Siddiqui Wajeeha , Abbas Zafar , Akhtar Imran , Khalid Muhammad Saif Ullah 
Published: September 2022

Abstract
In this paper, Rayleigh-Benard Convection (RBC) is investigated in a two-dimensional vertical cavity with the horizontal temperature gradient for Rayleigh numbers (Ra) up to 20000. The velocity and temperature fields along with the Nusselt number (Nu) are examined and discussed for various cases of aspect ratios (AR); 1 ≤ AR ≤ 100, along with examining the critical aspect ratio (ARcr). It is found that in the case of horizontal temperature gradient, convection starts at critical Rayleigh number ≈ 370. It is also observed that the fluid motion is initially restricted to wall proximity, but gradually as Ra increases, convection covers the whole cavity, including the core zone. Our numerical simulations show that as the AR increases beyond 13, for Ra = 6500 instabilities are observed in the cavity. Soon afterwards, secondary cells are formed and tend to decrease in number as Ra increases until the flow becomes fully turbulent. This computational study demonstrates that laminar and transition regimes get contracted with an increasing AR. Profiles of the averaged Nu for different AR are also provided on log Ra-log Nu map. The key finding of this research relates to the dependence of Nu on AR and Ra.
Performance Analysis and Parametric Study of Vortex Whistle
Authors: Li Ang , Chen Jun , Awan Jordan A. , Eddins David A. , Awan Shaheen N. 
Published: September 2022

Abstract
A vortex whistle is a low-cost but accurate flow meter. As the airflow passes through the whistle, a tone is produced which has a frequency proportional to the inlet air flow rate. Recent investigations using vortex whistles have focused on the use of this relationship to quantify aspects of respiratory function. Despite promising results, there is a lack of understanding of the physical mechanisms underlying vortex whistle function. In the present study, combined CFD and CAA method is applied to investigate the performance of the vortex whistle. A simplified vortex whistle model is simulated by LES with Smagorinskty model to predict the flow field within and outside the whistle, and then Ffocus-Williams and Hawkings analogy is used for aeroacoustic simulation to predict the acoustic response of the vortex whistle and the frequency and level of the signature tones. The result indicates that the spectral peaks are generated by the cylindrical cavity of the vortex whistle. The whistles with different heights and diameters of cylindrical cavity are also simulated to optimize the design. The results show that the height does not affect the harmonic frequency significantly; with the decrease of the diameter, the harmonic shifts to a higher frequency. It is beneficial for low flow rate cases; in addition, an optimal design exists which presents the largest signal-to-noise ratio. The simulation results and analysis in the present study help us determine which part contributes the signature peak, and increased SNR of the acoustic output by design optimization will allow for improved frequency-to-flow mapping and volume estimates during respiratory tasks such as the elicitation of vital capacity.
Modeling Intricate Unsteady Flow Field Development of a Self-Contained Novel Entry, Descent, Landing and Locomotion Planetary Exploration Module
Authors: Nordmann Alexandra , Blackman Trinity , Bayandor Javid 
Published: September 2022

Abstract
In the search for innovative concepts to explore extraterrestrial bodies, work towards modeling a fresh self-contained entry, descent, landing and locomotion (EDL-L) system, developed by CRASH Lab, was conducted. The system designed for atmospheric entry requires that the planetary aerodynamics are utilized on the descent to the planet’s surface to stabilize and land safely on the ground. The multifunctionality of this concept lies in the ability to contain all necessary landing configurations in one system. However, this requires extensive modeling to understand its interaction with the planetary atmosphere and environment during all phases of entry, descent, and landing. As the system has an open frame architecture for landing, it causes an intricate unsteady fluid flow to develop around the system as it falls. Being able to better understand how the flow evolves and how it affects the descending vehicle will allow for a more controlled EDL sequence. The free fall landing phase of the model has been considered at Venus Surface Conditions.
The work reported is centered around non-rotational descent, which will be extended in the future to rotational and multi-directional landing considerations, as well as verification studies with wind tunnel trials. The paper reports on efforts toward developing an ultimate predictive methodology and its verification and validation studies to assess the self-contained EDL-L system. One of the main objectives of the study is to achieve a more comprehensive understanding of the impacts that planetary conditions may have on the safe entry, descent, landing and operability of the concept vehicle on any celestial bodies with atmosphere.
The Impact of Scaling on the Gap Flow Rate of Radial Fans
Authors: Fritsche Manuel , Epple Philipp , Delgado Antonio 
Published: September 2022

Abstract
Due to the gap between the impeller and the casing of a radial fan a gap flow rate occurs, leading to a higher flow rate through the impeller than through the fan. The gap flow rate has an impact on the performance of the radial fan and must be considered in the design process. There is only little known from the literature about the gap flow rate. Furthermore, as to the knowledge of the authors, no information on the effect of scaling on the gap flow rate is reported in literature.
In this work a systematic study of the effect of scaling on the gap flow rate has been performed. For this first a baseline radial fan has been designed. This model and its full characteristics have been computed with the commercial Navier-Stokes solver Ansys CFX. Then the impeller width, the outer diameter, the inner diameter, the gap width, and the rotational speed were varied. These designs have been simulated with the commercial Navier-Stokes solver Ansys CFX. The effect of these parameters on the performance characteristics pressure and efficiency and its impact on the gap flow rate were evaluated.
Based on these results, a dimensional analysis model for the gap flow rate have been developed and evaluated with the full characteristics and the main dimensions of all simulated models. It has been shown that the gap flow rate can be estimated based on data that is typically available, such as pressure, volume flow rate, speed, outlet diameter, outlet width, gap width, fluid density and dynamic viscosity. The developed dimensional analysis model was validated with a test case. These results are presented and discussed in detail.
Numerical Investigation of Automotive Paint Oven for Improving the Thermal Efficiency
Authors: Pendar Mohammad-Reza , Páscoa José Carlos , Lima Rui 
Published: September 2022

Abstract
This study conducts a comprehensive numerical evaluation of conjugate heat transfer in an automotive paint oven to optimize the performance and increase the overall energy efficiency. Computational fluid dynamic (CFD) analysis of parameters in an automotive paint oven and on the coated vehicle surface is essential to achieve better paint quality and manufacturability, although the complicated geometry of vehicles, transient nature of the procedure, varying scales of the flow, and the tightly coupled conjugate heat transfer make the modeling difficult. An efficient computational algorithm, under the framework of the OpenFOAM package, using the Large Eddy Simulation (LES) turbulence model is implemented to numerically model the unsteady heated airflow behavior in the paint curing process. The conjugate heat transfer solver, chtMultiRegionFoam, is validated by heat sink case examination as heat transfer benchmark and then employed for the oven modeling. According to simulation results, the applied low-cost optimization of the intake hot flow rate and small oven geometry variation achieved significant energy efficiency improvement. During the optimization, the fluid dynamic characteristics, e.g., the mean temperature, velocity and streamline patterns, across all six zones of the oven, as well as the temperature and velocity map on a Body in White (BiW), are examined. The optimized arrangement and position of nozzles and panels for transient heat transfer processing of curing along the oven is described. Increasing the heated air provided by the panels on the lower half of the oven improves airflow circulation, resulting in a significant increment in the computed car body temperature.
Using Iterative Learning Control to Improve the Accuracy of Desktop Fused Deposition Modeling Printers: An Experimental Case Study
Authors: Funke Lawrence , Opara Matthew 
Published: September 2022

Abstract
Additive manufacturing (AM) sits poised to make a large impact on the manufacturing sector. Fused deposition modeling (FDM), a type of AM, while versatile, and increasingly appearing in full production systems, has performance limitations in certain geometries, such as arcs and holes. This is especially true for the desktop setups common in College Maker Spaces and other prototyping environments. For these use cases, it is critical to obtain accurate parts quickly, yet often difficult, diminishing the value of using FDM, whether it be to prototype new designs, make final parts, or anything in between. Iterative Learning Control (ILC) has been applied to robot control, plastic extrusion, and other similar processes where disturbances to a system are present and relatively constant, but difficult to model and correct. Since desktop printers perform repetitive tasks subject to nearly constant disturbances that induce inaccuracies, a natural research question arises: can ILC be used to allow desktop printers to learn these inaccuracies and account for them, allowing such printers to create more accurate and useful parts for the average prototyping user?
Details on the printer, a LulzBot Taz 6, and the scanner, an Einscan 3D Scanner, being used to answer this question are first presented with some baseline data to establish the scanner’s nominal accuracy. Subsequently, a simple bounding box approach was developed and tested where only the part’s length, width, and height were monitored and adjusted. This approach determined an error metric for a scalene triangular prism by determining the length, width, and height of a box that bounds the shape. The ILC algorithm used this error metric to generate a new file to print for the next iteration, thus creating parts that became more and more accurate. While this approach exhibited some success, it cannot account for larger, more common issues such as warping (where shrinking occurs as the plastic cools over time causing bending or bowing in the part), or a hole being geometrically inaccurate compared to the desired diameter. To address these concerns, a grid approach was developed where the cardinal dimensions had a grid overlaid so that points along each dimension could be checked and adjusted in subsequent prints to account for such issues. This approach was applied to rectangular bars with relative success. The overall dimensional accuracy (e.g. length, width, height) was not significantly improved, however, warping along the length of the bar was significantly reduced. A similar approach for more complex geometries, (i.e. holes and arcs) is currently under development. Initial thoughts and plans are presented as concluding remarks. Using ILC to account for common issues with desktop FDM printers could enable higher quality parts to be made, without a substantial investment in higher-grade equipment.
Non-Planar Slicing Method for Maximizing the Anisotropic Behavior of Continuous Fiber-Reinforced Fused Filament Fabricated Parts
Authors: Chen Chih-Yu , Freißmuth Leonard , Altug Suat Mert , Colin David , Feuchtgruber Matthias , Drechsler Klaus 
Published: September 2022

Abstract
Fused filament fabrication (FFF), a type of extrusion-based additive manufacturing method, has proven its suitability for the production of highly complex components without costly tooling. However, traditional FFF systems are restricted to planar layer deposition, which results in poor surface smoothness and a reduction in strength and stiffness along the layer-stacking direction. Recent advancements in the FFF process have made it possible to reinforce and strengthen the printed parts with continuous fibers, which significantly increases the material’s anisotropy. Therefore, non-planar printing is necessary to optimize the anisotropic material behavior. This paper proposes a non-planar slicing method for optimizing the performance of continuous fiber-reinforced FFF parts printed using a 6-DOF industrial robot. The computational framework allows for the deposition of material on non-planar surfaces along the direction of the largest principal stress obtained from a finite element analysis following topology optimization. Three parts were successfully sliced and printed in a non-planar manner to generate stress-oriented toolpaths for continuous fiber-reinforced FFF using a 6-DOF robotic arm.
Multiplexed 3D Printing of Thermoplastics
Authors: Cleeman Jeremy , Bogut Alex , Mangrolia Brijesh , Ripberger Adeline , Maghouli Arad , Kate Kunal , Malhotra Rajiv 
Published: September 2022

Abstract
Extrusion-based additive manufacturing of large thermoplastic structures has significant emerging applications. The most popular approach to economically achieving such 3D printing is to increase the polymer flow rate along with the layer height and line width. However, this creates a fundamental compromise between the achievable geometric fidelity and the printing throughput. We explore a Multiplexed Fused Filament Fabrication (MF3) approach in which an array of FFF extruders concurrently prints different sections of the same part using small layer heights and line widths. Mounting all the extruders on one cartesian gantry without individual control of each extruder’s motion enables simple machine construction and control. 3D geometric complexity is realized by rastering the extruder array across the smallest rectangle bounding each 2D layer and by spatially specific deposition via “dynamic” filament retraction/ advancement in the extruders. The dynamic moniker is because, unlike conventional single extruder FFF, the extruder array does not stop during dynamic filament retraction/advancement. This achieves higher throughput at greater resolution without material-intensive overprinting and machining, geometrically-limited throughput of the dual-extruder strategy, cost and geometric limitations of robot-based multiplexing, and the complexity and geometric limitations of previous gantry-based multiplexing efforts. Our experiments reveal the parameters that affect dynamic retraction and advancement, and show a previously unknown coupling between the efficacy of dynamic filament retraction and dynamic filament advancement. We create part-scale thermal simulations to model temperature evolution in the part under the action of multiple concurrently acting extruders, revealing a unique temperature history that can affect bonding and mechanical properties. We show that MF3 can enable resilience to extruder failure by allowing other extruders to take over part fabrication while the damaged extruder is being replaced. We also demonstrate that MF3 enables flexibility in part scale and geometry, i.e., the ability to make multiple smaller parts of similar or distinct geometries in one production run and lesser number of larger parts of similar or distinct geometries in the next production run. Finally, we quantitatively analyze the future potential of MF3 to achieve similar or greater throughput than state-of-the-art Big Area Additive Manufacturing while significantly enhancing the geometric resolution.
The Development and Validation of a Novel Thread Forming Fastener for High Strength Steel Applications
Authors: Ruszkiewicz Brandt J. , Breidenbaugh Eric , Simpson Gene 
Published: September 2022

Abstract
Automotive OEMs continue to lightweight their fleets to increase fuel economy and electric drive range to meet government requirements and consumer expectations. This push towards lightweighting has led to increasing use of advanced high strength steels in both car body and safety critical systems, such as seats. These steels present different challenges for traditional joining technologies, especially thread forming fasteners. Thread forming fasteners are externally threaded fasteners like machine screws that are driven into a pilot hole where they form their own threads and then tighten down to secure the target joint. Traditional thread forming fastener designs struggle to form threads into steels with tensile strengths greater than 600MPa. This paper utilizes simulation coupled with experimental validation to evaluate one of the most popular traditional thread forming fasteners that is currently used in low strength steel to determine why it fails to form threads in high strength steels. A new thread forming fastener design targeted for high strength steels is developed through simulation. The new fastener design is manufactured and evaluated across three different screw diameters, and six different high strength steels (&gt; 600MPa tensile strength) using the same heat treatments, materials, and platings as traditional thread forming fasteners. Validation tests for the new fastener include drive-to-failure to identify a target tightening torque and clamp load at the target tightening torque. Both tests are conducted across a hole size tolerance window. It is shown that the new thread forming fastener design performs well in steels up to 1200MPa without any special heat treatments but can benefit from specialized heat treatments in steels of tensile strength 1200MPa or higher.
Synthesis of Nano-Dots and Lines by Glancing Angle Deposition With Corrals
Authors: Qu Chuang , McNamara Shamus , Walsh Kevin 
Published: September 2022

Abstract
This paper introduces using GLancing Angle Deposition (GLAD) with corral seeds for synthesizing nanodots and nanolines. GLAD is an advanced physical vapor deposition technique for creating three dimensional nanostructures. GLAD is commonly combined with pre-determined seeds on the substrate to create periodic nanofeature arrays; the seeds are usually artificial nucleation sites to rearrange the deposition patterns. However, the concept of corral seeds is different: the incident vapor will be depositing both on and inside the sacrificial layer of the corrals that consist various shapes; the desired nanostructures are grown from the overlapped deposition areas inside the corrals while the substrate rotates, depending on the shape of the corrals, and eventually will be remaining on the substrate when the sacrificial layer of the corral seeds is removed. The thickness of the sacrificial corrals along with the incident angle of the vapor define the shadow areas and deposition areas inside the corrals on the substrate. In this paper, three types of corrals are introduced: circular corrals, dumbbell corrals, and line corrals. The different nanofeatures of nanodots, limited-length nanolines and wafer-length nanolines created by different shaped corrals are presented. The fabricated nanodots and nanolines are potentially used in various optical and sensing applications. The two-step fabrication process of preparing corrals and GLAD provides numerous benefits for the synthesis of the nanofeatures.