bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development of a Novel 4-Stroke Spark Ignition Opposed Piston Engine
Authors: Nunes Alexandre , Brojo Francisco 
Published: January 2022

Abstract
This project aimed to develop a low-cost, 4-stroke gasoline-powered opposed piston engine (OPE), joining two conventional internal combustion engines with side valves on the block and removing the heads. This modified engine has a combustion chamber confined to the space inside the cylinder between the piston heads and the chamber between the valves. The pistons move on the cylinder shaft in opposite directions, a typical feature of OPE.
It was studied the feasibility of building an engine from a different one already in use, to reduce the manufacturing and development costs. In addition, higher power can be obtained with better specific fuel consumption and reduced vibration.
The engine performance was compared between the stock and opposed-piston engines. The engine performance parameters, such as rotational speed, torque and fuel consumption, were measured on an eddy currents dynamometer. With the collected data, power, specific consumption and overall efficiency were calculated. The performance of both stock and opposed-piston engines were compared, allowing to conclude that the opposed-piston engine is a cost-effective solution, delivers more power and has reduced vibration.
A Data-Driven Approach for Estimating Postural Control Using an Inertial Measurement Unit
Authors: Giachin Anthony , Steckenrider J. Josiah , Freisinger Gregory 
Published: January 2022

Abstract
In this paper, we propose a probabilistic multi-Gaussian parameter estimation technique which addresses the complex relationship between acceleration and ground force signals used to derive a human’s static center of pressure. The intent of this work is to develop an accurate accelerometer-based method for determining postural control and neuromuscular status which is more portable and cost-effective than force plate-based techniques. Acceleration data was collected using an inertial measurement unit while ground reaction forces were simultaneously measured using a force plate. Various metrics were calculated from both sensors and probabilistic data models were built to characterize the relationships between the two sensors. These models were used to predict force-based postural control metrics corresponding to observed acceleration metrics. Data collected from one participant was used as a training set to which the test data of two individuals were then applied. We conclude that converted acceleration-based metrics on average can accurately predict all the corresponding force-based metrics we studied here. Furthermore, the proposed multi-Gaussian parameter estimation approach outperforms a more basic linear transformation technique for 75% of the metrics studied, as evidenced by an increase in correlation coefficients between true and estimated force plate metrics.
Analysis and Modeling of Vapor-Liquid Interactions in Condensing Ejectors
Authors: Wang Nanqiao , Bhatt Nirmal , Bhushan Shanti , Cho Heejin , Li Like 
Published: January 2022

Abstract
Ejectors are compact mechanical devices that utilize the expansion of a high-pressure primary fluid to entrain and compress a low-pressure secondary fluid by means of momentum transfer between the two streams of fluid. Condensing ejectors feature both momentum and heat transfer through the interaction between the vapor and liquid streams. This paper focuses on the thermodynamic analysis and computational modeling of the vapor-liquid interactions in two specific types of condensing ejectors — one with primary liquid and secondary vapor flows, and the other with primary vapor and secondary liquid flows. Control volume analysis of the mass, momentum, and energy balance in each phase and across the interface based on one-dimensional (1D) slug flow was conducted for the ejectors. The friction coefficient on the inner wall of the ejectors and the interfacial heat transfer coefficient are identified as controlling parameters for the ejector performance in terms of pressure and temperature distributions along the axis. The 1D slug flow models for both types of ejectors are validated with published results in the literature. After validation, in-depth parametric studies are presented to scrutinize the effects of major geometric parameters and operating conditions on the performance of both types of ejectors.
Performance Analysis of a Travelling-Wave Thermo-Acoustic Engine Using Artificial Neural Network
Authors: Ngcukayitobi M. , Tartibu L. K. , Bannwart F. C. 
Published: January 2022

Abstract
Thermo-acoustic systems can convert thermal energy into acoustic waves and vice-versa. These acoustic waves can be used to induce cooling (thermo-acoustic refrigeration) or generate electricity (thermo-acoustic generator). This conversion is due to the thermo-viscous interaction between the acoustically oscillating gas medium within a porous material, referred to as a regenerator, and the pore internal walls. Although there has been significant progress in the development of efficient thermo-acoustic systems, their relatively low efficiency and the nonlinearity associated with more severe working conditions remain their major issues. Therefore, it is a major potential area of research. In this study, a one-stage travelling-wave thermo-acoustic engine has been modelled using DeltaEC. The simulation was performed by considering various input heat to the hot heat exchanger within the range of 8.2 to 227.91W, and sixty (60) datasets were generated. These data were used to build an Artificial Neural Network (ANN) model. The comparison between the output data extracted from the DeltaEC simulation and the results predicted from the ANN model was done. Both of the results obtained are in good agreement and prove that the ANN can be suitable for predicting configurations that were not previously simulated.
Efficient Digital Modeling and Fabrication Workflow for Individualized Ankle Exoskeletons
Authors: Gebre Biruk A. , Nogueira Rodrigo , Patidar Shubham , Belle-Isle Robert , Nolan Karen , Pochiraju Kishore , Zanotto Damiano 
Published: January 2022

Abstract
We introduce a new design method to tailor the physical structure of a powered ankle-foot orthosis to the wearer’s leg morphology and improve fit. We present a digital modeling and fabrication workflow that combines scan-based design, parametric configurable modeling, and additive manufacturing (AM) to enable the efficient creation of personalized ankle-foot orthoses with minimal lead-time and explicit inputs. The workflow consists of an initial one-time generic modeling step to generate a parameterized design that can be rapidly configured to customizable shapes and sizes using a design table. This step is then followed by a wearer-specific personalization step that consists of performing a 3D scan of the wearer’s leg, extracting key parameters of the wearer’s leg morphology, generating a personalized design using the configurable parametric design, and digital fabrication of the individualized ankle-foot orthosis using additive manufacturing. The paper builds upon the design of the Stevens Ankle-Foot Electromechanical (SAFE) orthosis presented in prior work and introduces a new, individualized structural design (SAFE II orthosis) that is modeled and fabricated using the presented digital workflow. The workflow is demonstrated by designing a personalized ankle-foot orthosis for an individual based on 3D scan data and printing a personalized design to perform preliminary fit testing. Implications of the presented methodology for the design and fabrication of future personalized powered orthoses are discussed, along with avenues for future work.
Reinforced Mixed Mode Bending Fixture for Improved Characterization
Authors: Yekani Fard Masoud , Bonney Christian 
Published: January 2022

Abstract
The Mixed Mode Bending (MMB) test is a standardized material characterization technique used to determine the strain energy release rate and fracture toughness of layered composite materials under a range of combined mode I and mode II loading conditions. The compliance of any fixture’s internal components lessens the material characterization accuracy by introducing error into the displacement measurement. Correcting for system compliance often involves complex post-processing of data. To reduce error in the test and improve material characterization quality, the authors have redesigned the MMB test fixture for minimal compliance. An analytical model of the fixture was developed to isolate the components most responsible for system compliance. The components were modified, guided by a finite element optimization algorithm, to reduce deformation. The redesigned features reinforce the fixture without creating nonlinearity in the system or changing the test’s basic mechanisms that allow for variable mixed-mode ratios. The new MMB fixture will improve the accuracy of the experiment and reduce the complexity of data post-processing, leading to a safer crack-resistant design.
Applications of Electrochemical Impedance Spectroscopy (EIS) for Various Electrode Pattern in a Microfluidic Channel With Different Electrolyte Solutions
Authors: Kabir Shanzida , Ghosh Dipannita , Islam Nazmul 
Published: January 2022

Abstract
Electrochemical impedance spectroscopy (EIS) is a rapidly developing technique in microfluidics for characterizing materials and interfaces. By using equivalent circuits as models, it can determine the electrical properties of heterogeneous systems like membranes or electrolytes in a microfluidics chamber. For measuring Impedance spectroscopy, a small amount of perturbing sinusoidal signal was applied to the electrochemical microfluidic cell and measured the resulting current response. Two main ways to visualize EIS are Nyquist and Bode plot. In our research, both of these plots describe the characteristics of the electrochemical system in their ways. In our studies, we analyzed both the Bode plot and Nyquist plot for two different electrodes arrangement named as T shaped electrode (or orthogonal electrode) and V-shaped electrodes. We also compare these electrodes in three different electrolytes DI water (18.72μS/cm), tap water (666.12 μS/cm) and PBS 1× (8235.24 μS/cm) with three different ranges of conductivity to observe their characteristics changes and to compare them. We analyze the capacitive effect or electric double layer (EDL) effect for the electrode and electrolyte interface and how electron transfer kinetics and diffusional characteristics affect the spectra. As Impedance takes into account all factors such as capacitance, resistance or inductance besides the ideal resistor, it can define the characteristics of each different cell or electrode pattern by the spectra. For our microfluidics system, the capacitive systems are traditionally very large especially at the low frequencies because of impedance. The purpose of this research is to find the optimal operating range for different AC electrokinetic mechanism.
Molecular Dynamics Analysis of the Acceleration of the Degradation of the Strength of a Grain Boundary Under Creep-Fatigue Loads
Authors: Suzuki Shujiroh , Tezuka Shogo , Suzuki Ken , Miura Hideo 
Published: January 2022

Abstract
Since thermal power plants will be required to operate at random power output to compensate for the output instability of renewable energies, it is essential to consider the degradation damage of materials under creep-fatigue loading at high temperatures. Under creep-fatigue loading, the effective lifetime of Ni-based superalloys is known to decrease drastically, and the main reason for this was believed to be the change in the crack initiation and propagation path from transgranular to intergranular. Therefore, it is very important to identify the dominant factors that accelerate the degradation of the effective strength of grain boundaries under creep-fatigue loading.
In this study, molecular dynamics analysis was applied to the analysis of the degradation process of the crystallinity of grain boundaries. Bicrystal structures with different combinations of crystal orientations were modeled by considering the experimental results of the strength of bicrystal structures cut from polycrystalline materials. A strain-controlled creep-fatigue uniaxial load was applied to this bicrystal structure. Clear stress relaxation was observed even when the magnitude of the applied strain was much smaller than the yield criterion. The main reason for the stress relaxation was not only the local generation of dislocations around the grain boundary in the bicrystal structure, but also the accelerated ejection of atoms around the grain boundary, i.e., the grooving of the grain boundary to relieve the local strain concentration due to the lattice mismatch between nearby grains. This grooving behavior corresponds well to the accumulation of fine voids around grain boundaries under creep loads. These results indicate that under creep-fatigue loading, plural damage mechanisms are activated and they accelerate the damage accumulation and degrade the strength of grain boundaries, and thus, accelerate intergranular cracking.
Characterization and Modeling of How Environmental Aging Affects Fatigue Damage Evolution in Fiber Reinforced Polymeric Composites
Authors: Li Zhiye , Lepech Michael 
Published: January 2022

Abstract
Glass Fiber-reinforced polymer composites (GFRPs) are made by combining polymer with reinforcement glass fiber yarns to produce new materials that offer lightweight yet strong, durable, corrosion resistance. Its application is emerging in aerospace, the automotive and solar panel industry. Although decades of application have proved composite as a viable, permanent structural material, a reliable, experimentally validated model for the predictive performance for the composite under the expected environment is needed before this material can be used as a massive construction material. This study is to build a physics-based model to predict mechanical, thermal, weather and aging performance of the composite in the short- and long-term.
A multiscale modeling technique is used to upscale the usage of material model prediction into structural and system levels. In the multiscale computational model, there are two levels: materials level, structure level. The material level model has the smallest length scale. It consists of woven microstructure, periodic boundary conditions, and coupled multi-physical processes (radiation heat transfer, moisture condensation, polymer deterioration, and solid material behavior), which ultimately affect the mechanical performance of the material. These mechanisms will be computationally modeled using COMSOL® multi-physics modeling software. The material model will be used to generate an equivalent homogenized model that can be used at the structural level efficiently while maintaining the same accuracy.
The structure level model heritages the characteristic of the transportation model at the material level model and correlates the material degradation with structure-level mechanical loading such as fatigue damage. The model is validated by UV/moisture exposure and fatigue-damage experiment.
In the long term, the models developed in this study will be combined with life cycle assessment (LCA) tools to better support sustainability focused design of new material, thus reducing costs and environmental impacts of the built environment.
Meeting Electricity Demand With Distributed Wind and Solar Generation: System Flexibility Drives Optimal Siting
Authors: Antonini Enrico G. A. , Ruggles Tyler H. , Farnham David J. , Caldeira Ken 
Published: January 2022

Abstract
Hundreds of gigawatts of renewable technologies, such as wind and solar, need to be installed to reach a zero-carbon electricity system that meets current and future energy needs. Locations of new installations are typically chosen based on wind and solar availability to maximize facilities’ capacity factors. Here, we show that this is not always true in least-cost models, and optimal siting depends also on the flexibility of the electricity system. To show this, we use a macro-scale energy model to evaluate capacities and dispatch in least-cost electricity systems with distributed wind and solar generation supported by battery storage. If battery storage were free and widely available, chosen locations for wind and solar installations would inevitably be in regions with the highest wind and solar capacity factors. However, as the battery storage cost increases and thus storage capacity decreases, chosen locations have lower capacity factors and the electricity system is more reliant on wind generation. In the case of a system without energy storage, only wind generation would in fact meet certain periods of electricity demand. This study suggests that current optimal wind and solar siting may no longer be the least-cost solution as the storage cost decreases.
Process Parameter Effects on Melt Topology and Dimensional Deviation in Electron Beam Melted Ti-6Al-4V
Authors: Bol Eric , Doyle Curtis , Ramulu M. 
Published: January 2022

Abstract
Industry is actively evaluating additive manufacturing (AM) for parts and assemblies, but many applications have strict requirements that manufacturing processes be stable and repeatable. This is currently a challenge for many operators of powder bed fusion (PBF) technologies where limited understanding of how the AM process parameters impact the dimensional deviation from the design and material quality. The experiment described in this paper employed an electron beam melting (EBM) Arcam A2X and Ti-6Al-4V powder to manufacture single lines of melted powder within the bed. This fundamental approach was designed to identify variation and inaccuracy at the micro scale that could provide lessons applicable to the macro scale. It is a subset of a broader ongoing effort intended to characterize the manufacturing repeatability of the EBM PBF process.
The design of this experiment involved the placement of short line segments in various orientations within the build plane. Two different sets of process parameters were utilized to fabricate the CAD build geometry. Each line specimen was imaged and 3D scanned within the surrounding sintered powder to study the topology. Observations from the resulting measurements were correlated with the machine process parameters and log file data. The dimensional deviation of the melt - was characterized along with the minimum feature size. These findings provide valuable EBM design for additive manufacturing guidance to help improve quality and limit deviation in components produced for industrial applications.
Application of Bayesian Calibration to Improve Multiple Ballistic Impact Modeling
Authors: Langone Gregory A. , Davis Brad G. , Reisweber Nicholas A. 
Published: January 2022

Abstract
Analytical impact models for steel penetration, such as the Alekseevskii-Tate and Lambert-Zukas models, are a combination of physics principles and empirically derived constants fit by trial data to represent a specific experimental condition. These models are very useful to predict material performance under single impact conditions of a non-deforming or hydrodynamic projectile given suitable experimental test data but were not developed to account for the effects associated with repeated impact loading. The uncertainty in multiple impact events comes from variability in the impact location, effected area after impact, inertia induced fracture, material response to heating, and many other factors. Because of the meaningful uncertainty in multiple impact modeling, it is useful to apply Bayesian updating to formally combine the predictive capacity of an impact model with limited available test data to improve the model’s accuracy for a specific application and better quantify the uncertainty in the estimates. In this report, existing experimental data for impacts of 0.223 caliber ammunition against AR500 steel panels with 2-inch ballistic rubber is used for Bayesian updating. The existing data from the U.S. Army Aberdeen Test Center was gathered by shooting a steel plate while cycling through sixteen independent locations until one location is perforated. The total number of shots delivered to the plate was recorded as the number of shots to failure. Because sixteen independent plate locations were fired on, however, there is useful data from both locations where failure was not reached and those that were perforated. After creating the prior distribution of plate failure for a range of total impacts test data from all 48 locations is incorporated using Bayes’ Theorem to create a posterior distribution which represents an updated model for plate failure. The posterior density of plate failure strength — measured in number of shots at the failure location — can then be used as one parameter in a model to determine the safe allowable total number of impacts on the target of interest. This future model must also consider parameters such as the distribution of shots across the plate and the area affected by each impact while making assumptions about the practical variability in impact velocity and obliquity. A model of this type will inform decision makers to develop safe inspection criteria and utilize a safe number of impacts in training for current and future ammunition.
Undergraduate Research With Entrepreneurial Approach: Creating New Insulation Materials Using Biomass Fibers
Authors: Dikici Birce 
Published: January 2022

Abstract
Entrepreneurial approach suggests the creation and development of economic ventures. This study describes the activity for students for Clean Energy Systems course. The Undergraduate Research Integration is a project for students which is about writing a proposal report and giving presentations. Each team writes a research proposal during the course of the semester that involves the use of biomass composites. The proposal is assigned in the third week of the semester and is due at the end of the semester. Student teams performed a preliminary study to create, test, and document a new environmentally friendly material that will be used in their dorm insulation. This project introduces sustainable engineering issues to students. Students also have to bring biomass material samples collected from nature as a project deliverable. Adaptability, communication, and management skills influences the way people interact and engage with colleagues. Placing students in groups and giving them tasks that they depend on each other is a great way to utilize the social needs of students. Overall, increased level of student enthusiasm was observed compared to previous years. Students were engaged in group meetings and often lead asking questions at the group presentations in class. The creative nature of the project made students think outside the box and have interesting ideas.