bluuebunny/crossref_metadata_2025_split huggingface dataset:
Probabilistic Study of Corrosion Pit-Induced Fatigue
Authors: Starr Benjamin , Shishkin Serge L. , Sahay Chittaranjan , Ghosh Suhash 
Published: January 2022

Abstract
Corrosion fatigue is the major damage mechanism responsible for the premature failure of the aircrafts and turbine parts, especially in the marine environment. It has been seen that even relatively mild corrosive atmospheres can reduce the fatigue strength of many structures considerably as compared to their fatigue strength in dry air. The process starts with the surface degradation due to the corrosion pits, that become fatigue initiation sites and the initial damage when the part is loaded. Microstructure and morphology of the surface pits is critical for the crack initiation. It is assumed that the cracks are initiated at the sharp corners and bottoms of the narrow “micropits”. The paper provides a statistical characterization of the crack initiation process based on these pits’ density and microstructure distribution. Based on the surface damage initiation analysis, new morphological characteristics combining the pit size and highest curvature are introduced and have shown to be the efficient metrics for pitting fatigue with the distribution of introduced morphological characteristics. The distribution of these characteristics is estimated from the measured data. Effects of pitting morphology are evaluated for various heat-treated Aluminum 2024 specimens, with varying distribution of pit shapes and curvatures. The statistical distribution of specimen life is estimated using the “weakest link” approach, that is, by computing the probability that at least one crack is initiated anywhere on the surface. The paper contains a detailed description of crack initiation’s statistical model, methodology of corrosion parameter estimation and representative numerical examples of statistical modeling. The surface pit characterization has been nondestructively measured on a Zygo ZeGage 3D profiler. The ZeGage uses a Coherence Scanning Interferometry (CSI) technique which uses the wavelength of light to define its high precision. A carefully calibrated CSI profiler can measure a larger range of surface qualities with repeatable results in sub-nanometer precision. High magnification (20x, 50x, 100x) lenses increase the versatility in measuring even smoother surfaces. Large area scanning was done using a segmentation approach. A large field of view of the selected lens and automated rapid scanning allowed for reasonably smaller data files obtained after stitching these individual segments.
An Artificial Neural Network Model for Flexoelectric Actuation and Control of Beams
Authors: Yu Pengcheng , Fu Xiaogang , Fan Mu 
Published: January 2022

Abstract
The converse flexoelectric effect has been applied to precision actuation and vibration control of flexible structures. High stress concentration caused by a single flexoelectric actuator can be alleviated by placing multiple actuators on the structure. In the presented work, a neural network model was established to optimize the positions of multiple flexoelectric actuators on a cantilever beam. It was proved that the neural network can recognize the relationship between actuator position and tip displacement and forecast the tip displacement of the beam accurately with reduced computational effort and higher effectiveness. By using the neural network, the displacement data generated by all possible combinations of actuator positions were predicted, and the optimal positions of multiple flexoelectric actuators can be obtained in term of maximum transverse tip displacement. The effect of actuator size with various actuator numbers was discussed. The results showed that applied voltage can be reduced by increasing the number of flexoelectric actuators when placed on optimal positions.
Feasibility of Pumped Hydroelectric Storage Within Existing USACE Facilities: a Methodological Approach
Authors: Kass Kyle J. , Davidson F. Todd 
Published: January 2022

Abstract
Variable, renewable energy (VRE) generation such as solar power has seen a rapid increase in usage over the past decades. These power generation sources offer benefits due to their low marginal costs and reduced emissions. However, VRE assets are not dispatchable, which can result in a mismatch of the electric supply and demand curves. Pumped-storage hydropower (PSH) seeks to solve this by pumping water uphill during times of excess energy production and releasing the water back downhill through turbines during energy shortages, thus serving as a rechargeable battery. Creating new PSH systems, however, requires a large amount of capital and suitable locations. The United States Army Corps. of Engineers (USACE) is the largest producer of hydroelectric power within the United States, and as such, may have favorable sites for the addition of PSH. This study seeks to develop a method for evaluating these existing hydroelectric facilities using techno-economic methods to assess the potential for adding PSH. Each USACE facility was evaluated based on site specific characteristics from previously unpublished data to estimate the power generation and energy storage potential. The temporal nature of local wholesale electricity prices was accounted for to help estimate the financial feasibility of varying locations. Sensitivity analysis was performed to highlight how the method would identify the viability of facilities with different operational conditions. The methodologies detailed in this study will inform decision-making processes, and help enable a sustainable electric grid.
Effects of Turbulence Modeling and Turbulent Schmidt Number on Supersonic Mixing Simulations
Authors: Chowdhury Md. Navid , Aziz Sarfaraz , Shingh Shanto Kumar , Ali Mohammad , Amin M. Ruhul 
Published: January 2022

Abstract
The supersonic mixing flow field of a Helium jet in cross-stream air is numerically simulated in the present study by solving the two-dimensional Reynolds-Averaged Navier-Stokes equations. Turbulence contribution is obtained from the Realizable k-ε and the SST k-ω model. Each model is incorporated separately with four different turbulent Schmidt numbers, i.e., 0.50, 0.35, 0.25, and 0.20. The focus of this paper is to guide the selection of a suitable turbulence model with an appropriate turbulent Schmidt number for these types of complex mixing simulations. The results show that both of the models can predict the general flow behavior while exhibiting their advantages. A better agreement with the experimental data is obtained when the turbulent Schmidt number is gradually decreased. However, examining the critical characteristics like upstream flow separation, bow shock prediction, and mass concentration of Helium the SST k-ω model with turbulent Schmidt number 0.20 can be considered for the reasonable estimation of the supersonic mixing flow field.
Terrestrial Mission Extender for Weather Balloon Radiosonde
Authors: Chun Carrington , McBride Joseph , Torabzadeh Kaveh , Smith Andrew , Roberts Santana 
Published: January 2022

Abstract
Thousands of balloon-assisted meteorological sensor packages, known as radiosondes, are launched every day from various monitoring stations across the continental United States. However, only a small fraction of these instrument payloads are ever recovered, with most ending up as hazardous electronics waste strewn across the country. By creating a terrestrial landing system that can be retrofitted to common commercially available radiosondes, the landing survivability of these instrument payloads may be able to be improved. Furthermore, such a landing platform could also support continued meteorological data acquisition and transmission, allowing the radiosonde to transition from high-altitude monitoring to surface level sensor monitoring. Not only would such a terrestrial mission extension module fitted to a radiosonde drastically increase the potential utility of an existing radiosonde, but such a device could also improve radiosonde recovery rates, and therefore reduce the electronics waste being produced by regular weather balloon launches.
An Approach to Variation Simulation of Final Aircraft Assembly With Presence of Sealant
Authors: Eliseev Artem , Lupuleac Sergey , Grigor'ev Boris , Shinder Julia 
Published: January 2022

Abstract
Sealant is usually put between joined parts of an aircraft prior to final assembly. This paper presents an attempt to estimate the influence of sealant on assembly quality in terms of variation analysis. The modeling approach is based on simulation of two-way coupled fluid-structure interaction between fluid sealant and compliant parts. Reynolds lubrication approximation is used in the fluid dynamics problem and variational formulation of contact problem combined with static condensation is used in the structural one. An approach based on initial gap modelling is used for variation analysis.
The joining of two aircraft panels is used as a numerical test for demonstration of developed approach. Various phenomena connected with the presence of sealant are demonstrated. In particular, the difference in fasteners loosening due to sealant flow between different types of fasteners was investigated. Results of variation simulation show that presence of sealant may be considered among determining factors in the analysis of assembly quality.
Methods for the Design of Individual Mechanisms for the Fabrication by Additive Manufacturing
Authors: Schroeffer Andreas , Irlinger Franz , Lueth Tim 
Published: January 2022

Abstract
Additive Manufacturing (AM) enables the quick and cost-effective generation of complex geometries and therefore new business models such as individualized products. The time-consuming step thereby is no longer the production, but the design of the parts. The key to solve this issue is the development of algorithms for automated process-specific design.
Currently, the design process for parts fabricated by AM is still characterized by the procedure used for traditional fabrication processes. Several manual steps are necessary, requiring time and expert knowledge.
At our institute, a MATLAB integrated design toolbox is developed, trying to overcome these issues. The basic idea is an algorithmic approach to design problems and a direct generation of surface models that can be fabricated in an AM process. It can be used to realize design tools that allow to define parts by their functionality and not by their geometry.
In this work, the toolbox is used to create automated design algorithms for individual compliant mechanisms. A novel droplet-based AM process enabling hard/soft multi material printing is used to fabricate the parts. The scope of the software provides a component library of flexure hinges, mechanical connectors, and grippers that are generated from functional descriptions given by the design engineer.
Several application examples of compliant mechanisms realized with the software are shown. An experiment is presented showing investigations of how well functional specifications can be reached.
Validation Approach for Energy Optimization Models of Grid-Interactive Buildings Using Co-Simulation
Authors: McCurdy Patrick J. , Pattawi Kaleb , Wang Chenli , Roth Thomas , Nguyen Cuong , Liu Yuhong , Lee Hohyun 
Published: January 2022

Abstract
The consumption and production of energy are more dynamic as distributed energy resources (DERs) such as solar photovoltaics (PV) are deployed within the electric distribution system. The existing techniques for bulk generation do not take full advantage of DERs and can lead to wasted energy and higher costs for both utility companies and consumers. Commercial and residential building energy management systems are usually on a fixed schedule and are not able to respond to changes in energy price instantaneously. There is a need for a real-time pricing structure that can accommodate the fluctuating cost of energy based on supply and demand, and for an energy management system that is able to respond to the dynamic utility rate. As such, there is a need for a robust energy management control strategy and methodology to validate new approaches.
To address this gap, a strategy to control heating, ventilation, and air conditioning (HVAC) systems in a residential house was developed along with a validation methodology. A model of predictive control was implemented to optimize the thermostat setpoints and minimize energy cost for an individual residential house while maintaining thermal comfort of residents. This model was integrated with EnergyPlus simulation via an open source co-simulation platform previously developed at the National Institute of Standards and Technology (NIST). Total energy consumption and cost for consumers were compared between a case with the proposed model and a baseline case that used fixed-temperature setpoint control. The simple dynamic pricing model used in simulations was proportional to the demand of energy at that time of day. This work will contribute to the development of dynamic utility pricing models and residential control strategies for grid-interactive buildings and homes. The outcome of this research can be expanded to different building models or locations in future work.
Improving Real-Time Methane Monitoring in Longwall Coal Mines Through System Response Characterization of a Multi-Nodal Methane Detection Network
Authors: Cappellini Brian , Johnson Derek , Clark Nigel , Barr Amber 
Published: January 2022

Abstract
Methane released from coal during underground mining operations imposes a significant threat to the workers safety and consequently limits production. This paper introduces a method for the monitoring of methane emissions that are released during longwall coal mining operations. Furthermore, it describes the methodology used to test and develop the system’s response characteristics for improved measurement accuracy. The Methane Watchdog System (MWS) is a multi-nodal network of sensors currently under development to improve the safety and productivity during mining operations. The MWS consists of 10 compact sampling units designed to be integrated within the current roof support equipment of mines. Each unit contains an array of sensors to continuously monitor the environmental conditions which include methane concentration, temperature, pressure, and relative humidity. Reduced one-dimensional (1-D) modeling studies provided a useful tool to simulate the longwall mining environment. From the 1-D studies, multiple scenarios were constructed to generate temporal methane distributions that were the result of ventilation and production patterns. Model results were extracted from the proposed MWS sampling locations and used to demonstrate its usefulness and effectiveness within the laboratory setting. The resulting outputs from the system were then used to develop a signal reconstruction technique, which effectively sharpened response times and improved real time measurement accuracy.
A Reactor Train System for Efficient Solar Thermochemical Fuel Production
Authors: Patankar Aniket S. , Wu Xiao-Yu , Choi Wonjae , Tuller Harry L. , Ghoniem Ahmed F. 
Published: January 2022

Abstract
Thermochemical redox cycles are a promising route for the production of solar fuels. In this paper we present a novel Reactor Train system for efficient conversion of solar thermal energy to hydrogen. This system is capable of recovering thermal energy from redox materials, which is necessary for achieving high efficiency, but has been difficult to realize in practice. The Reactor Train System overcomes technical challenges of high temperature thermochemical reactors like solid conveying and sealing, while enabling continuous, round-the-clock fuel production and incorporating efficient gas transfer processes and thermal energy storage.
The Reactor Train is comprised of several identical reactors arranged in a closed loop and cycling between reduction and oxidation steps. In between these steps, the reactors undergo solid heat recovery in a radiative counterflow heat exchanger. We report a heat recovery effectiveness of 75–82% with a train consisting of 56 reactors and a cycle time of 84 minutes. With ceria as the redox material, 23% of the high temperature thermal energy input is converted to hydrogen, while 49% is recovered as intermediate-temperature heat at 750 °C.
Modeling of Residual Stress in Micro-Grinding Considering Texture Effect
Authors: Zhao Man , Liang Steven Y. 
Published: January 2022

Abstract
Residual stress is an important mechanical property parameter and a key evaluation index of the surface integrity. Residual stress induced in micro-grinding is related to the process parameters, the wheel properties, and material microstructure. The micro-grinding process is distinct from the conventional grinding owing to size effect, and the crystal effect. Typically, the effects of crystallographic orientation (CO) on process behaviors are significant by influencing the flow stress of workpiece material due to the depth of cut is usually less than the average grain size. In this paper, a Taylor factor model is developed to estimate the effect of CO on the flow stress and plastic modulus of monocrystalline materials. The flow stress model takes into account strain, strain rate, temperature, and material microstructure including grain size, CO, and dislocation density. The plastic modulus of monocrystalline materials h is given as the function of hardness, strain, and microstructure. The analytical model of residual stress is proposed considering the effects of CO. The hybrid McDowell algorithm is used to predict the residual stress with the developed plastic modulus. Finally, the sensitivity analysis is carried out, with the result showing that the effect of CO on residual stress is significant.
Effect of the External Multi-Frequency Excitations on Dynamics of a Ring Structure Rested on Elastic Foundation
Authors: Gao Nan , Wang Shiyu 
Published: January 2022

Abstract
This work aims to reveal the connections between the basic parameters and instabilities induced by the multi-frequency excitations on an elastic ring structure. An analytical dynamic model considering the geometric nonlinearity is established by using Hamilton’s principle and the nonlinear in-extensional assumption. Based on this assumption, the external excitations arise at the stiffness coefficients of vibration equations, which is different from the current researches. The external excitations not only affect natural characteristics but also lead to parametric instability. The natural frequency split occurs owing to the distributions of the excitations. Considering the presence of multi-frequency such as the rotation and fluctuation frequencies, the effects of the multi-frequency excitations on parametric vibrations are investigated. By discussing the parameters, two cases are examined and the instability zones are obtained by using Floquét theory. The results show that the parametric instabilities induced by the multi-frequency excitations are not a simple superposition of instability zones regarding each single-frequency excitation. Furthermore, the instabilities of the intersection regions of each frequency are larger than expected, and the extra zones can be found when the combination frequencies are closed to the natural frequency and its multiples. The instabilities are more complex when the natural frequency split is involved. The demonstration and analysis of this model could be an innovative understanding for similar rotational symmetry structures.
Protic Ionic Liquids as Lubricant Additives
Authors: Saran Om , Stoyanovich Brandon , Guo Hong , Iglesias Patricia 
Published: January 2022

Abstract
Protic ionic liquids (PILs) are an emerging class of environmentally friendly lubricants and lubricant additives PILs can be easily synthesized through proton transfer from a Brønsted acid to a Brønsted base and exhibit significant potential as lubricant additives on account of their high thermal stability, non-flammability, low melting points, lack of vapor pressure, low cost, and biodegradability. This research covers the tribological performance of three halogen-free protic ionic liquids, 2-hydroxyethylammonium 2-ethylhexanoate (Eet), 2-hydroxyethylammonium p-toluenesulfonate (Ets), and 2-hydroxyethylammonium 4-dodecylbenzenesulfonate (Eds) which are designed and synthesized using the same base (ethanolamine) but different acids of varying acidity and alkyl chain length. The relationship among their ionicity, molecular structures, and tribological properties are investigated when these protic ionic liquids are used as lubricant additives to water. Each PIL was evaluated as a lubricant additive in a 1 wt.% aqueous solution. The solutions were tested using a ball-on-flat reciprocating tribometer under room temperature for steel-ceramic contact using distilled water was used as a base line lubricant. PIL solutions yielded significant reductions in frictional coefficients and wear volumes. The wear mechanisms and surface interactions were also discussed in terms of PIL-steel surface interactions from SEM and EDX data.
Towards an Assistance and Simulation Augmented Reality Environment for the Manufacturing Area
Authors: Valdivia Puga José Abraham , Urbina Coronado Pedro Daniel , García Martínez Rubén Febronio , Ahuett Garza Horacio , Orta Castañon Pedro Antonio 
Published: January 2022

Abstract
The present work was carried in a manufacturing context, using augmented reality as the main tool. The main goal is to explore the capabilities of augmented reality used in manufacturing environments through connectivity and a digital shadow. Novel features implemented include control, interactions, and display of information not only of machines but any element connected to the industrial IoT. These features are addressed by the implementation of infrastructure prepared to communicate with different kinds of protocols. Additionally, a discrete event simulation of the manufacturing cell is created through specific software and connected with its 3D model to visualize the process and relevant information in AR. With this implementation, it is possible to establish a communication environment between machines, robots, and any element connected to the network. Also, this concept enables the visualization, control, interaction, and sending/receiving information of processes in real-time. Then, any person can see process information anywhere and interact within the AR model using a capable device. Therefore, AR applied in combination with other I4.0 tools allows to have high-level intelligent processes and increase operator’s abilities in manufacturing environments. The application of the proposed concept into modern manufacturing facilities was discussed and reviewed.
Gravity Balancing Design of a 3-DOF Hybrid Robotic Manipulator With Variable Payloads
Authors: Nguyen Vu Linh 
Published: January 2022

Abstract
This paper presents a design method for compensating the gravity effect of a three-degrees-of-freedom (3-DoF) hybrid robotic manipulator with variable payloads. The manipulator is constructed by a pair of 2-DoF parallelogram-based five-bar parallel mechanisms combined with a 1-DoF serial mechanism. The balancing design of the manipulator is realized by attaching two balancing units to the five-bar parallel mechanism, where each unit is made by a geared seven-bar mechanism with a linear spring. The parameters of the balancing units are analytically derived from the static equilibrium of the mechanism. The design method is also effective when the payload is varied and the spring stiffnesses are prescribed. Examples are then given to illustrate the effectiveness of the proposed method. The method was also validated by simulation software. The simulation results showed that, by using the balancing design, the actuation torques of the manipulator could be reduced by more than 98% with different applied payloads.