bluuebunny/crossref_metadata_2025_split huggingface dataset:
An Efficient Time-Domain Model to Simulate Parametric Resonances in a Floating Body Free to Move in Six Degrees of Freedom
Authors: Kurniawan Adi , Tran Thanh Toan , Yu Yi-Hsiang 
Published: February 2023

Abstract
We present a computationally efficient time-domain model capable of simulating parametric resonances in a floating body in waves. The model assumes all wave forces to be linear, but the inertia and restoring forces acting on the body are expanded to second order in body motions. The simulation speed on a standard computer is approximately 40 times faster than real time. The model is applied to a soft-moored floating axisymmetric body which absorbs energy through heave, but is otherwise free to move in six degrees of freedom. Under certain conditions, we show that the body undergoes parametric resonance with large amplitudes not only in surge and pitch, but also in sway, roll, and yaw, provided it is given some small initial displacement in one of these out-of-plane modes. The predictions are confirmed by simulations using state-of-the-art nonlinear Froude-Krylov and computational fluid dynamics models.
Safe Design of Gas-Management Systems for Turning Bolt-Action Rifles in View of Known Ammunition Mismatch Hazards
Authors: Munsell W. P. 
Published: February 2023

Abstract
Ammunition mismatch refers to a phenomenon by where the chamber of a firearm can accommodate more than one caliber of ammunition. This is possible due to the historical development of firearms and ammunition which has been largely unregulated, and therefore lacking in any commonly agreed-upon rules for architecture. If a user inadvertently chambers an oversize caliber round, the result is usually a failure of the shell casing during discharge due to the lack of proper support from the chamber walls. These failures manifest themselves as burst case-heads and/or primers which allow the rearward flow of expanding gases. Such flows may harm the user directly through direct contact with flame or excessive heat, or indirectly by initiating an over-pressure which fractures the magazine well and rifle stock. Shrapnel from this secondary failure can maim or kill the user or by-standers in the vicinity. The lack of a standardized performance criteria for this issue has resulted of a mix of designs in the marketplace which expose users to vastly different levels of risk. This disparity is not communicated to the user in any way, and up until now has not been formally studied and quantified in a published, peer-reviewed paper for use by the technical community.
This paper presents the results of a battery of both nondestructive and destructive experiments performed on two major manufacturer’s designs. New methods of analysis are explored, quantified, and compared to live-fire test data. Most importantly, the question of whether an economically feasible design which safely manages gas flow under the condition of ammunition mismatch is answered. It was found that effective measures are available to prevent user injury under at least some ammunition mismatch conditions, and that the incorporation of these measures is not correlated to the price point of the product.
Producing High-Strength Pellets From Seaweed, Sawdust, and Hay for Gasification
Authors: Nazemi Mohiodin , Safavi Aysan , Camille P. Bonthonneau Eyja , Richter Christiaan , Unnþórsson Rúnar 
Published: February 2023

Abstract
Hay, invasive lupine plants, wood chips, and seaweed are the four abundant biogenic fuel options in Iceland. These four biomass types are potential renewable fuel feedstock as they can be converted into syngas or high-value fuels using thermochemical processes such as pyrolysis and gasification. In this study, we focus on biomass pelletizing, which is a major process for preparing various kinds of feed for either gasification or controlled combustion as in powerplants and heat applications. Pelletizing is producing a low-humid, dense, and uniform shape of feedstock, which is appropriate for the continuous and efficient performance of the gasifier. The pellets need to be dense enough not to collapse in the hopper while being fed to the reactor. The challenge in this study is to produce high-quality pellets with high energy content, high strength, and optimized moisture level from abundant biomass types in Iceland that can be gasified efficiently and continuously in the gasifier. To address this challenge, we pelletized blends of hay, wood chips, and seaweed with different percentages. In this study, we focus on the strength of the pellets. The experiments suggest that up to a hay fraction of 20 wt.% a higher hay content results in a stronger pellet. Based on our experiments, pellets made only from wood are typically not strong enough for gasification. It was observed that after running several pelletizing experiments continuously, the temperature of the discharged pellets increased, and this parameter influenced the strength of the pellets.
Preparation of Hybrid Alkaline Cement Based on Natural Zeolite As Sustainable Building Material
Authors: Cornejo Mauricio , Baykara Haci , Garcia Natividad , Garces Juan , Correa Walter , Frere Cecibel , Torres Julio 
Published: February 2023

Abstract
Alkaline hybrid type cement is an interesting multi-component system that incorporates a high content of mineral additions, low content of Portland clinker (CK) (&lt; 40%), and alkaline activator. The development of these types of cement allows a significant reduction in the clinker factor, thus leading to an economic and mainly environmental benefit.This study explores the possible development of such cement. Hybrid cement samples were prepared by alkaline activation of the natural zeolite, mainly composed of mordenite, and utilizing a NaOH solution. After mixing with OPC and with an alkaline solution, zeolite-rich tuff formed cement pastes with an activator/binder ratio of 0.5 that were cured for 24 hours at room temperature and then for 7 days underwater. The optimal alternative was evaluated based on compressive strength, quantitative X-ray diffraction, and Fourier Transform Infrared spectroscopy. As a result, the best dosage was that of 60% zeolite ruch tuffs and 40% CEM Type I showing values of compressive strength of 10 and 14 MPa at 7 and 28 days, respectively.
Machine-Learning Approach to Modeling Oxidation of Toluene in a Bubble Column Reactor
Authors: Tayeb Raihan , Zhang Yuwen 
Published: February 2023

Abstract
A feed forward machine-learning (ML) model is applied to study bubble induced turbulence and bubble mass transfer in a bubble column reactor. Using direct numerical simulation data for forced turbulence, bubble deformations and flow velocities are predicted. To predict mass transfer, ML sub-grid scale (SGS) modeling technique is introduced for the concentration of reactants and products undergoing parallel competitive reactions in the oxidation of toluene. The ML model replaces the iterative approach associated with the use of analytical profiles for previous SGS models for correcting concentration profiles in boundary layers. The present model, thus, offers a significant performance bonus as well as the flexibility to extend to more complex scenarios due to its data-driven nature.
Virtual Vibrations Laboratory
Authors: Mohammadzadeh AliReza , Haidar Salim M. 
Published: February 2023

Abstract
Lacking a physical vibrations lab, a series of virtual experiments were developed and deployed to enhance students’ understanding of topics covered in the Study of Vibrations course. MATLAB and SIMULINK were utilized to simulate response of single-degree and two-degree freedom systems to free vibrations, damped vibrations, harmonic forced vibrations, and transient unit step excitations. Using the scope and power spectral density windows in SIMULINK, clear understanding of stable and unstable response of the system for different system parameters and excitations were examined. Beating phenomenon, together with system resonance to harmonic excitations were realized. Phase diagram together with instability, and stability of the response along with limit cycles were simulated and analyzed. Response of nonlinear systems to different initial conditions in free vibrations together with forced harmonic and transient excitations were simulated and analyzed. These experiments promote functional understanding by design of important concepts and theories in Vibrations. Also, they provide for an effective economical means to expose additional students to the instrumentation of modeling and simulation-based laboratories. These experiments and their ensuing uses will be presented in this paper along with corresponding students’ learning outcomes.
Attaining Nonlinear Hardening Stiffness in Piezoelectric Vibration Applications Using Passive Nonlinear P-N Junction Capacitance
Authors: Taşkıran Muhammed Ali , Özer Mehmet Bülent 
Published: February 2023

Abstract
Piezoelectric vibration isolation and energy harvesting applications has been studied extensively. Nonlinear approaches may provide better performance over a broader frequency range. Nonlinearity can be introduced in the mechanical domain or electrical domain actively or passively. Since electrical components can be in smaller scales compared to mechanical counterparts, nonlinearity in the electrical domain can be more practical and convenient. Moreover, passive structures require no energy supply and controller therefore they are simpler and more reliable than active ones.
In this paper, a novel way to attain passive hardening stiffness was presented for piezoelectric vibration isolation or energy harvesting. Nonlinearity was suggested to be attained with use of nonlinear capacitance of P-N junction in electrical domain and its capacitance model is introduced. A piezoelectric patch operating in d33 mode is considered and modelled as a single degree of freedom (SDOF) linear stiffness element without internal damping. force vs. displacement curves obtained by the models and finite element method (FEM) showed that hardening stiffness can be achieved. Frequency domain analysis is conducted for hardening stiffness and effect of piezoelectric coupling coefficient on resonance frequencies investigated. It is explored that resonances of nonlinear frequency response curves are bounded by open and short circuit resonance frequencies. Lastly, whether theoretically analyzed hardening capacitor is realizable or not is discussed.
Towards the Deep Learning-Based Autonomous Collision Avoidance
Authors: He Binxin , Xiao Youan , Wang Tengfei , Li Zhuo 
Published: February 2023

Abstract
Reinforcement learning (RL) is considered as an effective method to avoid ship collision. In this study, a ship collision avoidance method based on MADDPG in RL is proposed. In algorithm, some indicators, including DCPA, TCPA, relative distance and relative velocity between ships, are calculated and then collision risk index and the best way point are calculated. In the implementation part, by gathering observational information, setting the reward of the agent and restricting the action of the agent, the agent can learn an effective strategy after training. When there is a risk of collision, the ships in the environment can make reasonable actions to avoid collision. The final experiment verifies the effectiveness of this method.
Application of Artificial Neural Network to Predict the Performance of Thermoelectric Power Plants at Design Conditions
Authors: Carapellucci Roberto , Giordano Lorena 
Published: February 2023

Abstract
Recently Artificial Neural Networks (ANNs) have been gaining an important role in the analysis of complex power cycles, since they have the potential to reduce the computational effort in designing and control of power plants operating conditions compared to rigorous thermodynamic models.
This paper presents a novel methodology for the prediction and optimization of the performance of thermoelectric power plants at design conditions using ANNs. The methodology involves a preliminary study to randomly generate the dataset of input variables (i.e., power plant operating conditions) and evaluate the dataset of output variables (i.e., energy and economic performance indicators) via thermodynamic simulation. Using these datasets, ANNs are trained and validated. Finally, the ability of ANN algorithms to replicate thermodynamic models is assessed in terms of absolute relative errors and coefficient of determination. The proposed methodology is flexible with regard to the type of power plants to be replicated and the extent of the investigation, that can be easily adapted by properly selecting the set of input and output variables.
To prove its feasibility, the methodology is applied to a coal-fired power plant and a triple-pressure reheat combined cycle. In both case studies, the methodology provided a very good accuracy in predicting the power plant behavior and optimizing their energy or economic performance.
A Comparative Study of Disk Wear Volume Evaluation of Al2024 Based on ASTM G99
Authors: Salguero Jorge , Iglesias Patricia , Vazquez-Martinez Juan Manuel , Batista Moises , Del Sol Irene 
Published: February 2023

Abstract
In this paper, a comparative study between the three different methods proposed in the ASTM G99 standard for volume loss calculation in tribological Pin-on-Disk tests is presented. The mass/density and the geometrical methods (exact and reduced approximation) have been applied to the evaluation of aluminum/WC-Co tribological pair, providing similar results, with differences lower than 7%. However, adhesion wear mechanism typically found in aluminum alloys, is not considered in this method, increasing the differences between mass and geometrical methods, which stands the need of a corrector factor for wear evaluation in soft materials.
On the Stability Analysis of a Double-Link Inverted Pendulum Subject to an Oscillatory Tilted Excitation
Authors: Taherian Babak , Shankar Praveen 
Published: February 2023

Abstract
This paper presents the study of the stability characteristics of a two-link (double) inverted pendulum system subject to a tilted and oscillatory excitation at the bottom pivot. Each of the two links are assumed to have a concentrated point mass at their ends. The excitation force acts at the bottom of the first link and its amplitude, frequency and tilt angle can be varied. The system is also assumed to have very light damping between the two links. Euler-Lagrange formulation is used to develop the equations of motion of the double-link inverted pendulum which results in a non-autonomous dynamic system. The method of multiple timescales is implemented to convert it to an autonomous system which allows for determination of the equilibrium points. Bifurcation analysis of the damped and undamped system with respect to frequency and amplitude of the input excitation is performed using a continuation analysis software. Further, the evolution of the equilibrium points and their stability properties of the system using extensive Monte-Carlo simulation of the nonlinear system as several parameters such as damping coefficient, excitation frequency and tilt angle are varied is presented.
Structural Evaluation of a Lapidus-Type Cuneometatarsal Arthrodesis
Authors: Mancera-Campos Natali , Hinojosa-Buenrostro Josseline Paola , Vidal-Lesso A. , Martínez-Bocanegra Marco Antonio , Bayod-López Javier 
Published: February 2023

Abstract
The numerical models developed to analyze the hypermobility of the first ray are varied since this is considered the most common condition to which the cause of a varied type of pathologies of the adult foot is attributed. Lapidus-type arthrodesis is one of the treatments most used to correct it. However, no works analyzed, numerically, the biomechanical behavior of the foot bones related to the surgical technique; or the plate used for the procedure. Therefore, the effects of fixation on bones and the structural strength of the plate are unknown.
For the above, in this work, a 3D nonlinear finite element analysis of arthrodesis in the cuneometatarsal joint of the first ray is performed, for which a simplified foot model is used and inserted with a Lapidus plate that fixes the plantar area.
The results found with this model indicate that the insertion of the plate contributes to reducing the hypermobility up to 124 % for the hallux angle parameter and contributes to the bones reaching a considerable percentage (42.87%) of their ultimate stress. Although these values do not exceed the ultimate stress of the material, neither in bone nor in plate, it is suggested to carry out an analysis that includes the trabecular part of the bone since the stress found with this model exceeds the ultimate stress value of this material.
Acceleration of Intergranular Cracking in Ni-Base Alloy GH4169 (IN718) Due to the Growth of δ-Phase Around Grain Boundaries Under Creep Loading at Elevated Temperatures
Authors: Nakayama Ayumi , Wang Runzi , Miura Hideo 
Published: February 2023

Abstract
In this study, intermittent creep tests were conducted on GH4169 (IN718) at 800°C to elucidate the degradation mechanism of the grain boundary strength accompanied by microstructural changes under mechanical loading at elevated temperature. The microstructural degradation process was visualized by EBSD (Electron Back-Scatter Diffraction) method and the degradation of the strength of grain boundaries was verified by a micro tensile test in a scanning electron microscope using FIB (Focused-Ion Beam) apparatus. Under the creep loading, the precipitation of δ-phase (Ni3Nb) was found to grow around grain boundaries. The δ-phase precipitates grew around grain boundaries by the coarsening of the solute strengthened γ″ phase in this alloy. Thus, the growth of the δ-phase caused the disappearance of the solute strengthened phase in the surrounded grains. As a result, the effective strength of grains decreased, and the effective strength of grain boundaries increased by the precipitation strengthening around the grain boundaries. The effective strength of grain boundaries, however, started to decrease with time due to the acceleration of the growth of vacancies and dislocations around the interfaces between the precipitates and the matrix. This accumulation of defects was attributed to the large lattice mismatch between the precipitate and the matrix. As a result, intergranular cracking was accelerated. The change of the effective strength of a grain and a grain boundary was validated by the micro tensile test of bicrystal structures cut from the damaged polycrystalline alloy during the intermittent test.
Modeling the Damage Initiation of White Matter Brain Tissue During Indentation
Authors: He Ge , Fan Lei 
Published: February 2023

Abstract
Understanding and modeling the mechanical behaviors of white matter brain tissue is important to gain insights into brain injury. With embedded axonal fiber bundles, white matter is typically treated as an anisotropic material whose mechanical behaviors and properties are extensively studied and characterized through experimental approaches in the past decades. However, although the injured brain tissue may experience large deformation in some head impact scenarios, most works characterize the white matter in a small-strain regime to avoid the large deformation-induced damage. Both experimental and modeling studies of white matter at large strain are still few, especially when the damage effect is included. We recently performed the indentation tests on porcine white matter with the indenter having a large displacement and found a clear damage initiation and progressive failure behavior of white matter when deformed beyond certain strain levels. To model this behavior, we assume that this failure phenomenon is caused by the fracture of axonal fiber bundles and propose a coupled hyperelasticity-damage constitutive model. The proposed constitutive model is implemented into finite element codes that is used to reproduce the indentation process. Results show that by using this proposed constitutive model with identified parameters, the finite element simulation can reproduce the damage initiation observed in experiments.
Thermo-Mechanical Process Modeling of Additive Friction Stir Deposition of Ti-6Al-4V Alloy
Authors: Raihan Gazi Abu , Chakravarty Uttam K. 
Published: February 2023

Abstract
In this study, a computational fluid dynamics (CFD) model is developed to investigate the thermal-mechanical process in additive friction stir deposition (AFSD), a novel additive manufacturing (AM) process allowing site-specific deposition. Material conversation law with a steady-state heat is applied where the heat generation is measured considering stacking/slipping boundary conditions and the spatial heat flux is incorporated using ANSYS user-defined functions (UDFs). For measuring the temperature evolution throughout the process, the conservation of energy equation is solved where the heat is generated from the dynamic contact between the tool and feed rod interfaces. For material flow, the laminar viscous model is adopted where the feed rod is considered as a non-Newtonian visco-plastic material, and the viscosity and strain rate are temperature-dependent. The simulation results show the temperature evaluation of the deposited material as a highly viscous flow where the temperature is optimized around 20% below the melting point temperature of the feed rod. Since the heat generation depends on the rotational and translational motion of the feed rod, the maximum temperature changes with varying process parameters. Finally, the results of the simulation such as temperature evolution, heat flux, material velocity, etc are exhibited with varying process parameters.
An Investigation on a Novel Soft Metamaterial for Space Applications
Authors: Pulok Mohammad Khairul Habib , Sarker Pratik , Chakravarty Uttam K. 
Published: February 2023

Abstract
Naturally available materials are inadequate in many advanced applications, including space. Therefore, functional materials answer the requirement of operation-specific customized characteristics. Soft matter-based metamaterials exhibit various desired physical properties for space applications in terms of mechanical, optical, acoustic, and electromagnetic behavior. A composite metamaterial is studied in this project comprising an intricate hexagonal-shaped fractal geometry of SU-8 with a soft platinum-catalyzed silicone Ecoflex 00-30 infused in the cavities of the rigid skeleton. The finite element models of the proposed metamaterial are developed for computational study. Mechanical behavior in tensile, fatigue, shear, and modal responses are studied using the finite element model. The von-Mises stress, equivalent strain, total deformation, fatigue life, natural frequencies, mode shapes, etc., are among the properties that are investigated in the computational study. This benchmark cases of similar experimental situations are considered to compare and validate the computational model. Results show that the maximum stress is shared by the hard skeleton, and maximum strain is developed in the soft elastomer regions of the metamaterial. The material properties of hard and soft elastomers imply a change in the modal characteristics in terms of natural frequencies. This type of new functional metamaterials opens new opportunities, especially with the fatigue-resistant performances for applications requiring stretchable materials.