bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigation of the Acoustic Performance of Plantain (Musa Paradisiacal) Fibre Reinforced Epoxy Biocomposite
Authors: Imoisili Patrick , Nwanna Emeka , Enebe George , Jen Tien-Chien
Published: February 2023

Sound is produced by the fluctuation of oscillation waves caused by variations in pressure in a medium containing various frequency ranges, which can be detected by either an animal or a human auditory apparatus and then transferred to the brain for analysis. Noise can be diminished and controlled by using absorptive materials. This is necessary because noise has a negative effect on public health, sharing of knowledge, and serenity, and it is getting worse every day as a result of urbanization and increased affiliated functions. Utilization of natural and synthetic reinforced polymer composites in noise pollution control is an emerging area of research. Natural fibers could potentially replace synthetic fibre reinforced composites due to their low impact on human health and environmental friendliness, according to research. Though academics have been excited about studying their mechanical features, little attention has been paid to quantifying their sound reduction behaviours. Natural fibers, when interacting with a variety of sound frequency and intensity, the varied structures of sound absorbing materials, such as porous structure, hollow structure, multi-dimensional size and length structure, or solid composite materials, having their own distinctive sound absorbing capabilities. This study aims to develop and examine the void content, impact, hardness and acoustic properties of a natural fibre reinforced biocomposites. Natural fibre was extracted from plantain (Musa paradisiacal) fibre (PF), using the water retting method. Extracted fibre wasd used to prepare a fibre reinforced biocomposite using an epoxy resin as the matrix. Biocomposite with 5, 10, 15 and 20 (Wt. %) PF content were fabricated. Impact, hardness and void content analysis was conducted on prepared biocomposite in triplicate. Surface morphology of the fracture surface of prepared biocomposite was examine using a scanning electron microscope (SEM). Porosity and sound absorption coefficient properties of the fibre reinforced biocomposite were also investigated. Test analysis shows that impact, hardness and void content of the biocomposite, increases as PF content increases. Maximum hardness and impact strength were observed at 15 (w %). SEM analysis, shows the existence of cavities on the fracture surface, together with rough fibre surfaces that easily trap air, and this feature tends to boost the biocomposite’s sound absorption qualities.The sound absorption coefficient shows improvement as fibre volume increases in the bio composite. Results suggest that of PF reinforced biocomposites could be less costly, feasible and ecologically superior alternatives to synthetic fibre composites for acoustic applications in areas like building architecture and automotive industries.
Dielectrophoretic Movement of Cell Passing Between Surface Electrodes in Flow Channel
Authors: Hashimoto Shigehiro
Published: February 2023

In this study, cell behavior in microchannels has been tracked for the application of dielectrophoresis to biological cell selection. A pair of titanium surface electrodes integrated with a microflow channel was manufactured by photolithography technology: a triangular electrode with a tip angle of 0.26 rad and a rectangular electrode. A periodic alternating current of a square wave with a period of 0.33 μs was introduced between the electrodes to induce an asymmetric electric field perpendicular to the mainstream direction. During the flow of the suspension of mouse myoblasts (C2C12: mouse myoblast line), the behavior of the cells was measured in vitro. In addition to the shifted movement of cells by dielectrophoresis, the relationship between the distance from the electrode and the change in cell shape was investigated. Experimental results show that the distribution range of the shape of the two-dimensional projection of the cell expands under the influence of dielectrophoresis. The dielectrophoretic effect can be applied to classifying cells not only by cell size, but also by cell deformation.
Performance Evaluation of a Helicopter Main Rotor Hydraulic Control System Using Rotor Equivalent Dynamic Parameters
Authors: Düzağaç Hasan Ali , Çalışkan Hakan , Balkan Raif Tuna
Published: February 2023

Hydraulic control systems are commonly used in helicopter main rotor control applications because of the agility of the system and operational capability under heavy loads. It is significant to obtain better performance from hydraulic control system to ease the helicopter control under heavy loads. In this study, a complete helicopter main rotor hydraulic control system is modeled by using MATLAB/Simulink® to simulate system responses. Kinematic model of helicopter input is obtained. Hydraulic interface of a Flight Control Actuator is obtained. Pitch (α) and Roll (β) angle of stationary swashplate is obtained. Finally, 3 degrees of freedom rotor equivalent model is obtained. To enhance the overall dynamic performance of the system, a PI controller is developed and implemented to the system by an additional actuator. Furthermore, feedback system is modified to have a more stable controller by adding a feedback actuator, to give position of equivalent rotor mass as feedback to Flight Control Actuator. It is concluded that adding a PI controller is highly beneficial in terms of extending the controllable frequency range. Furthermore, modified feedback system is found to be extremely beneficial by decreasing amplitude and improving overall dynamic characteristics.
Gesture Recognition and Master-Slave Control of a Manipulator Based on sEMG and CNN-GRU
Authors: Ge Zhaojie , Liu Weiming , Wu Zhile , Cai Mei , Zhao Ping
Published: February 2023

Surface electromyography signal (sEMG) is the bioelectric signal accompanied by muscle contraction. In gesture recognition, sEMG is a non-invasive, efficient and fast recognition method. For patients with hand amputation, their upper limb EMG signals can be collected, and these EMG signals correspond to the patient’s hand movement intention. Therefore, by wearing the prosthetic hand integrated with the EMG signal recognition module, patients with hand amputation can also make gestures meet their needs of daily life. In this paper, gesture recognition is carried out based on sEMG and deep learning, and the master-slave control of manipulator is realized. At the same time, gesture recognition can also be applied to remote control. Controlling the end of the manipulator at a certain distance with a specific gesture can complete some tasks in complex and high-risk environments with higher efficiency. Based on Convolutional Neural Network (CNN) and Gate Recurrent Unit (GRU), this paper constructs three neural networks with different structures, including single CNN, single GRU and CNN-GRU, and then train the collected gesture data set. According to the results of test set, the input type with the highest accuracy of gesture classification and recognition can be obtained. Among the three neural networks, CNN-GRU has the highest accuracy on the test set, reaching 92%, so it is used as the selected gesture recognition network. Finally, combined with the integrated manipulator, the EMG signals collected in real time by the myo EMG signal acquisition armband are classified by the upper computer, and the results are obtained. Then the control signal of the manipulator corresponding to the gesture is sent to the Arduino control module of the manipulator, and the master-slave control of the manipulator using the EMG signal can be realized.
Influence of the Anisotropic Characteristic on the Accuracy of Acoustic Emission Source Localization With L Shaped Sensor Cluster
Authors: Sun Jiaying , Yu Zexing , Xu Chao
Published: February 2023

Composite materials are increasingly being used in the structure of aircraft. However, this type of materials is commonly encountering damage companied with acoustic emission (AE) events. In order to ensure the safety of structures during service, it is urgent to develop structural health monitoring methods able to localize AE source in composite components as they occur. Kundu et al [1] for the first time proposed a technique using L-shaped clusters to localize AE source in anisotropic plates without knowing the pre-defined velocity. However, the direction dependent group velocity may lead to a large error if the group velocities in some anisotropic materials vary widely. In this paper, whether the characteristic of anisotropy has a great influence on the localization results and the principle of how this characteristic affects the AE source localization results are investigated. The results show that localization results of isotropic plate are obviously better than that of anisotropic plate due to the direction dependent velocities of anisotropic plate, which proves that the characteristic of anisotropy will affect AE source localization results. It is also found that the variation of localization orientation error is consistent with the local velocity gradient.
Empowering Master Students to Pull What They Want to Learn
Authors: Alves Anabela C. , Lopes Nunes Manuel , Braga Ana Cristina
Published: February 2023

This generation of students is a generation that needs a meaningful education. This implies that students must believe that the contents they are learning has a purpose. The best way to do this is by allowing them to pull what they want to learn. However, this is difficult to achieve because the contents of the course is pre-determined by the teachers in a well-defined curricular plan. Still, the authors of this paper and teachers of a course called “Seminars in Industrial Engineering” were able to allow students to do so. Students were encouraged to plan an event, a training session or anything else they wanted, to learn more about Industrial Engineering. The conditions were that students worked in teams and used the schedule time for the lecture (Friday from 6pm to 8pm). This challenge was very welcomed by the students that formed eight teams of five to six members each. Each team approached a different topic in each session. The assessment of the activity involved various components. For instance, teams had to assess colleagues’ activities using similar criteria as the ones used by teachers. The performance of student teams was high. The feedback with this activity was positive and students showed satisfaction and proudness of their achievement. This feedback was gathered using a questionnaire at the end of the semester, and 28 (68%) questionnaires were completed. The main findings pointed out that students appreciated this kind of activities allowing them to learn and develop autonomy and creativity skills.
A Modified Time Reversal Based Probabilistic Imaging Method for Composite Plate Delamination Detection
Authors: Nan Yang , Yue Maoling , Fan Haodong , Du Fei , Wen Lihua , Xu Chao
Published: February 2023

Composite materials have been widely used in aerospace manufacturing because of their low mass, high specific strength, high specific stiffness and good fatigue resistance. However, composite structures are susceptible to damage such as debonding and delamination due to various impacts, vibrations and other external loads. Therefore, it is crucial to regularly monitor composite structures in real-time during spacecraft service to ensure the safety and reliability of the structures. Ultrasonic guided wave is an effective means of monitoring the health of composite plate structures. Delamination, debonding and other damages of composite materials can be imaged and localized using ultrasonic guided wave signals and probabilistic imaging methods. However, due to the large damping of composite materials, the traditional probabilistic imaging method has the problem of low accuracy in damage localization. Therefore, in this paper, we propose a probabilistic imaging method based on a modified time reversal for damage localization and imaging of delamination damage. The proposed method was experimentally validated using a composite plate as a test piece and compared with the conventional method. A fully automated falling hammer impact tester was used to create low-velocity impact damage on specimens to compare the localization accuracy of the time-free reverse method and the modified time reversal method for delamination damage. The results show that the modified time reversal method can better localize and image the delamination damage of composite structures with higher localization accuracy and more sensitive to damage, which verifies the feasibility and accuracy of the method in the localization of debonding damage of composite structures.
Thermal Performance of Phase Change Material Based Heat Exchangers
Authors: Soanker Abhinay , Oztekin Alparslan
Published: February 2023

Phase change materials (PCM) tend to have high energy storage densities and can be an excellent option for thermal energy storage systems. However, the low thermal conductivity of PCM creates a critical problem in effectively transmitting heat energy into these thermal storage systems. One of the solutions is to design these heat exchangers to diffuse heat into the thermal storage systems effectively. Numerical simulations have been performed to investigate the thermal performance of two heat exchanger designs, fin base heat exchanger (FHE) and Helical coil-based heat exchanger (HCHE). Ansys, Fluent has been employed to carry out transient three-dimensional numerical simulations. These simulations are also compared with two different inlet velocities of 0.02m/sec and 0.1m/sec, corresponding Reynolds numbers of 2,012 (laminar regime) and 10,061 (turbulent regime), respectively. FHE melting rates were observed to be much more stable. Total accumulated energy stored during the charging process for the laminar flow regime is higher in HCHE than in FHE. Energy stored is comparatively higher in FHE when the flow is turbulent. The energy discharge followed the same trend as the charging cycle. FHE tends to maintain consistent energy charging and discharging rates compared to HCHE.
Designing a Particle Flow Control Apparatus
Authors: Malik Sheharyar , Anderson Keldon , Goel Nipun , Otanicar Todd , Karimi Soroor
Published: February 2023

Flow control within a particle-based Concentrated Solar Power (CSP) system is essential in determining the heat transfer coefficient, and therefore, the power generation capability of these systems. There are three areas where particle flow control is significant: the receivers, storage tanks, and particle-sCO2 heat exchangers. The focus of this paper is on designing a new mechanism to control the flow in the particle-sCO2 heat exchangers due to the simplicity and potential cost savings when compared to the other areas of interest. The goal is for this new design to have quicker response times in terms of particle flowrate than a slide gate or flow control valve, which are designs currently used. The design resembles that of a chuck mechanism within a drill where a rotation of the sleeve elicits movement of the jaws both vertically and horizontally to close the outlet area of the nozzle. Additionally, this design will utilize the current actuator that is already used within these heat exchangers to reduce the complexity of implementation. The jaws are designed to be closed at an angle of 76° which is just slightly steeper than the hopper leading to the mechanism. Furthermore, this design can be tuned to limit particle bridging and other particle flow phenomena that result in blockages. The prototypes were 3D printed out of polylactic acid (PLA) and scaled up to 100%, 200%, and 400% to be able to observe the velocity profiles of the mechanism more clearly. Experiments are performed with this prototype to compare the inlet and outlet mass flow rates at different configurations of the jaws. The particles used in these experiments are 0.3mm HSP 40/70 that are commonly used in particle-based CSP systems.
Efficient Solar Thermochemical Hydrogen Production in a Reactor Train System With Thermochemical Oxygen Removal
Authors: Patankar Aniket S. , Wu Xiao-Yu , Choi Wonjae , Tuller Harry L. , Ghoniem Ahmed F.
Published: February 2023

Solar Thermochemical Hydrogen Production (STCH) is a promising technology that uses high-temperature heat directly to split water. The authors have previously proposed a Reactor Train System (RTS) that addresses the largest source of inefficiency in state-of-the-art STCH systems — solid heat recovery — by using multiple moving reactors that exchange heat radiatively between STCH steps. In this work, another major source of inefficiency — oxygen removal during metal reduction — is addressed.

Two oxygen pumping schemes are considered — vacuum pumping (VP) and thermochemical oxygen pumping (TcOP). For vacuum pumping, the modularity of RTS enables a ‘Pressure Cascade’ which reduces pumping work by a factor of four and the capex by a factor of five as compared to a single-step VP scheme. The optimized RTS + VP system achieves 31% heat-to-hydrogen conversion efficiency with ceria despite the low efficiency of vacuum pumps at low pressures.

Thermochemical Oxygen Pumping (TcOP) uses a second redox material — SrFeO3 — to pump oxygen. This material is transported in reactors moving in the opposite direction to the main RTS train. The optimized RTS + TcOP achieves morethan 40% heat-to-hydrogen efficiency, while producing twice as much hydrogen per kilogram of ceria as the RTS + VP system.
Heat Transfer in Liquid Nitrogen Cooled Superconducting Transformers: An Experimental Investigation
Authors: Orchuk Sean , Chandra Sanjeev
Published: February 2023

A single-phase, 15-kilowatt electric transformer was modified to replace the secondary copper winding with one formed of Yttrium Barium Copper Oxide [YBCO] superconducting ribbon. YBCO ceramics offer exceptional electrical efficiency at high current when properly cooled to cryogenic temperature. For the present research, a high ratio transformer design induced secondary currents above 200 amperes. This exploited the properties of the YBCO in reducing thermal losses inherent to high currents in conventional conductors. YBCO must operate below its critical temperature of 92K to avoid damage and is typically cooled by immersion in a pool of cryogenic liquid. Immersion cooling makes inefficient use of the cryogen, and a novel cooling method was proposed by the current research. The YBCO was routed within an insulating tube through which liquid nitrogen flowed and the entire assembly operated within a vacuum to minimize heat transfer. To conserve cryogen while respecting the YBCO critical temperature of 92K, the latent heat of nitrogen was exploited and the system designed to operate near the nitrogen boiling point of 77K. The resulting multi-phase system was operated at various conditions and a combined efficiency formula proposed which includes the energy cost of cryogenic fluid. The results demonstrated a 5% efficiency improvement using YBCO materials using a novel tube-cooling arrangement and provide a basis for future research and industrial use.
A Machine Learning Framework for Physics-Based Multi-Fidelity Modeling and Health Monitoring for a Composite Wing
Authors: Makkar Gaurav , Smith Cameron , Drakoulas George , Kopsaftopoulos Fotis , Gandhi Farhan
Published: February 2023

Computational mechanics is a useful tool in the structural health monitoring community for accurately predicting the mechanical performance of various components. However, high-fidelity models simulated through the finite element analysis (FEA) necessitate a large amount of computing power. This paper presents a new approach to develop a multi-fidelity model using artificial neural networks for health monitoring purposes. The proposed framework provides significant savings in computational time compared to a model trained only using high-fidelity data, while maintaining an acceptable level of accuracy. The analysis is conducted using two finite element models, of different fidelity, of an unmanned aerial vehicle (UAV) wing, with damage modeled at six locations, and varying severity. The damage is modeled by changing the stiffness properties of the materials at these locations. The algorithm developed aims at minimizing the number of high-fidelity data points for correcting the outputs of the low-fidelity model. It was observed that the low-fidelity model requires 8 high-fidelity data points to meet the desired error tolerance. This corrected low-fidelity model is then used for locating and quantifying the damage given the strains and frequency by expanding the previously trained network to output damage diagnosis results. The model with applied correction is able to locate the damage with an accuracy of ∼ 94% and quantify the damage with an accuracy of 93%. The performance of the corrected low-fidelity model is compared with a network trained only with high-fidelity datasets and it was observed that the corrected model requires 54% fewer data points as compared to the high-fidelity trained network.
Effects of a Solenoid Magnetic Field and an Electromagnet Magnetic Field on the Turbulent Flow and Heat Transfer of Conductive Gases in Circular Tubes
Authors: Zhao Qijin , Mao Baoquan , Bai Xianghua
Published: February 2023

A magnetic field can interact with a conductive fluid to form a magnetohydrodynamic effect, which can change the flow and heat transfer characteristics of the fluid. This introduces broad application prospects for magnetic field control of conductive gases in tubes, which is useful for thrust control of aero-engine nozzles, energy control of magnetohydrodynamic power generation channels, and anti-ablation of high-temperature tube walls. In this study, distributions of parameters, including the induced current, the electromagnetic force, and the Joule heat, in circular tubes under a solenoid magnetic field and an electromagnet magnetic field, are obtained and variations in the flow and heat transfer characteristics of conductive gases are analyzed through numerical simulations. The research results show that an applied solenoid magnetic field suppresses the turbulence and heat transfer of a conductive gas to a small extent, and that the suppression effect is isotropic. However, an applied electromagnet magnetic field significantly suppresses the turbulence and heat transfer of the conductive gas, and the suppression effect is anisotropic. Within a certain range of Hartmann number (Ha), the average Nusselt number at the tube wall decreases with increases in the Ha of the electromagnet magnetic field.
Identification of Flaws and Assessment of Mechanical Properties in Additively Manufactured Titanium Parts Using Acoustic Resonance Ultrasound Spectroscopy (RUS)
Authors: Taheri Hossein , Williams Caleb , Krenek Russell , Weaver Gregory , Taheri Mohammad
Published: February 2023

Additive manufacturing (AM) techniques are becoming accepted as routine in many industrial fields that include aerospace applications. This ramp up in manufacturing has highlighted a fundamental need for innovative nondestructive testing (NDT) methodologies for AM inspection and qualification purposes. Resonance Ultrasound Spectroscopy (RUS) is beginning to be applied as an innovative NDT inspection technique for AM components to obtain insights from the parts’ structural integrity and because it correlates to mechanical properties. RUS is used to understand sensitivity to detecting internal flaws, resulting in lower than expected failure resistance or fatigue life. Multiple test bar batches using the Ti6Al4V alloy were fabricated by powder bed fusion (PBF) AM technique at different processing conditions. RUS and destructive tests, including tensile and fatigue tests, based on ASTM standards are performed in order to evaluate the mechanical properties and tensile and fatigue strength of the parts. Finally, metallography experiments revealed the microstructure of the parts. The goal of correlation analysis is to establish the defect-NDT-property relationship for the Ti6Al4V by showing the strength and significance of the relationship between the testing data and the properties of the samples. Results show that RUS is a reliable and capable NDT technique to acquire rapid information for this purpose. This information is crucial for expanding the production and application of AM components while making sure that the mechanical properties, their structural integrity, and part safety satisfy the requirement of the lifetime operation.
Experimental Investigation of the Robustness of Bulk Metallic Glass-Based Tooling for Microinjection Molding
Authors: Almalki Ahmed , Rajhi Ali , Noor Hussam , Kundu Animesh , Coulter John
Published: February 2023

The primary objective of this research was to experimentally investigate the robustness of a commercially available zirconium-based bulk metallic glass material (Zr-based BMG) for microinjection molding (μIM) tooling. The focused ion beam (FIB) direct milling process was utilized to fabricate microfeatures onto two BMG-based mold inserts.

Uncoated and Ti-coated inserts were inspected through molding cycles utilizing SEM. Additionally, TPU molded samples were characterized to quantify the replication quality of the inserts through molding cycles. This is to understand the polymer melt effect of the tooling during molding conditions.

The uncoated BMG insert was utilized for more than 1000 molding cycles regardless of the potential crystallization. No signs of any crack initiation were observed in any part of the BMG insert. Through molding process, the replication quality degraded due to the polymer adhesion to the microcavity base.

In the case of the coated BMG insert, the coating could not withstand the high ejection force during demolding stage. The adhesion between the coating and the BMG surface was insufficient to survive molding conditions. This resulted in disintegrated coating that was bonded into molded samples.
Benefit of Optimal Actuator Selection – A Comparative Study
Authors: Hanna Pavlos , Carmichael Marc , Clemon Lee
Published: February 2023

Actuators are a vital component, and often the limiting factor in robotics and robotic-related applications like humanoids, exoskeletons, prosthetics and orthosis. Actuator selection is critical due to system design flow-on effects including weight, energy consumption and form factor. A designer’s challenge is often to optimize the actuator to minimize size or weight and meet the performance specifications usually with trade-offs. This paper investigates the design impacts of selecting more suited actuators on the system through a representative humanoid configuration performing a task. It also looks at variations based on the scale of the humanoid using human anthropometric data for variations in limb lengths. The torques and speeds required at each joint to complete the task is simulated and the system design is updated to keep a constant member stress across all designs. The total energy and weight are calculated and used to compare actuator selection impacts. By knowing the extent of the flow-on effects actuator selection has on a configuration, and how this effect scales, designers are able to determine what investment should be allocated to locating the ideal actuator for their task.
Bolted Lap Joint Monitoring Using Ultrasonic Guided Waves Considering Temperature Variations
Authors: Peng Xuezhi , Shen Yanfeng
Published: February 2023

This paper presents the numerical investigation of ultrasonic guided waves for bolted lap joint Structural Health Monitoring (SHM), considering temperature variations. It first systematically discusses the mechanisms behind the linear and nonlinear ultrasonic techniques for bolt loosening detection. Afterwards, a general Finite Element Model (FEM) of a bolted structure was established to observe and verify the influence of the change of bolt pre-tightening force on the linear and nonlinear characteristics of ultrasonic guided waves. In order to further study the effect of temperature variation on the sensing signals, the structure is subjected to various levels of thermal loads. This study examines the temperature influence on both linear and nonlinear signal features, such as the transmitted wave energy and the nonlinearity of waveforms. Simulation results show that an increment in temperature can cause partial detachment of the interface between two lap joint components in the structure, resulting in a decrease in both the linear energy and the degree of nonlinear higher-order harmonics. The paper finishes with concluding remarks and suggestions for future work.
Investigation of Mechanical Properties of Combinatorial Ti-Cu Film Using MD Simulation With Neural Network Potential
Authors: Miyagawa Takeru , Sakai Yugo , Yonezu Akio , Mori Kazuki , Kato Nobuhiko , Ishibashi Keiji
Published: February 2023

Combinatorial approach is a prominent method to synthesize samples with atomic composition gradients, which enables the high-throughput discovery of new materials. Titanium-copper (Ti-Cu) alloy is widely used in electronic devices because of its excellent mechanical properties such as stress relaxation resistance, bond formality, and workability. By synthesizing Ti-Cu thin film with combinatorial approach, the mechanical property may be improved, leading to a new application. Molecular Dynamics (MD) simulation is a powerful tool to predict mechanical property, but it requires interatomic potentials to depict the movements of atoms. Because of the complex structures of Ti-Cu thin film synthesized by combinatorial approach, the creation of interatomic potentials is a difficult and time-consuming process. Therefore, in this study, a neural network (NN) based method to create interatomic potentials is developed, which are referred to as neural network potentials (NNPs). It is found that NNP can accurately reproduce the energies and forces calculated by Ab initio molecular dynamics (AIMD) simulations. Finally, using MD simulations with developed NNP, the mechanism of mechanical properties is investigated from the perspective of atomic scales.
Numerical Study of Inclination Effect on a Flat-Place Direct Absorption With Water-Nanofluid Mixtures in Summer and Winter Conditions
Authors: Buonomo Bernardo , Cardillo Fabio , Chirico Pietro , Manca Oronzio , Nardini Sergio , Russo Giovanna , Scapaticci Angela , Vicidomini Ivan
Published: February 2023

In this work, a computational study on two-dimensional forced convection inside a volumetric solar collector based on a nanofluid with water and nanocarbon horns is carried out in steady state regime. A surface heat transfer from the upper wall of the solar collector toward the external ambient is present. The analysis is accomplished with governing equations assuming the single-phase flow model for the nanofluid mixture. The evaluation of heat transfer in the participating media due to the local absorption of nanoparticles is obtained employing the non-grey discrete ordinates method. The finite volume method is employed to find the solution and the simulations are obtained using ANSYS-FLUENT code. The analysis is accomplished to estimate the solar collector behaviors as a function of the inclination angle under different conditions in summer and winter regimes for residential use site in Aversa (Italy). The analysis allows to evaluate the thermal and fluid dynamic behaviors of the solar collector with an inclination angle from 0 to 90 degrees. Temperature and velocity profiles as well as temperature fields inside the channel are reported for different inclination angles, solar radiations and nanoparticle volumetric concentrations.
Structure-Resistance Relationship of 3D Printed Electrically Conductive Woodpile-Structured Metamaterials
Authors: Vasilyan Hayk , Lapuz Oginne , Susantyoko Rahmat Agung , Almheiri Ahmad , Alyammahi Mozah
Published: February 2023

This work proposes metamaterial with a woodpile arrangement constructed of its electrically conductive constituent material. Electromechanical response of woodpile structured metamaterials, when compressed, was experimentally studied. Specifically, when they are compressed in the stacking direction, with struts symmetrically staggered in alternating layers. Additive manufacturing has enabled the fabrication of metamaterials with tunable electromechanical properties. Herein, the structure-resistance relationship was established as a function of microstructural parameters described by the geometry of the repetitive elements of the structure, such as characteristic diameter, length, or thickness. The relationship also can be expressed in the form of relative density. We found that conductive metamaterials with staggered-woodpile architecture could effectively manipulate the electrical properties when compressed due to their local bending motions and contact between members. Such metamaterials could have high sensitivity as well as high stiffness – low sensitivity by controlling the spacing and diameter of struts. The findings from this study suggest that structured woodpile metamaterials are promising as strain sensors when mechanically implied or human-induced forces are present. When loaded at ∼3 % compressive strain, the materials appeared to have a typical transition phase from high to low resistance.
Numerical and Experimental Investigation of Rheodrop Technology
Authors: Alqosaibi Khalid , Alemmrani Mohammed , Almalki Ahmed , Duhduh Alaauldeen , Coulter John
Published: February 2023

A novel invention to advanced hot runner-based injection molding called Rheodrop technology is introduced. The technology allows control over the melt rheology inside the hot drops during/between injection molding cycles. The concept is to rotate the valve pin inside the hot drop to apply a controlled shear rate to the polymer melt. Doing so eliminated the incomplete filling defects associated with molding thin-walled parts and allowed processing at a lower melt temperature. The applied shear stress by Rheodrop technology was investigated utilizing ANSYS fluent software. The maximum shear stress that the polymer gets exposed to during the injection molding cycle was specified using Moldflow software. The results showed that the Rheodrop applies less shear stress than what the polymer gets exposed to during the injection molding cycle. Thus, utilizing Rheodrop does not cause additional damage to the polymer melt. Rheometric analyses were performed to investigate the polymer degradation for ABS. The reduction rate of viscosity was the same for samples that were injection molded conventionally and samples that were molded using Rheodrop technology.
A Note on Probability Quantification for Protective System Efficacy Analysis: Stochastic Dynamics, Information Flow, and Initiating Event Arrival Times
Authors: Wortman Martin , Kee Ernest , Kannan Pranav
Published: February 2023

Probability Quantification (PQ) predictions of the efficacy of safety-critical protective systems is challenging. Yet, the popularity of PQ methodologies such as, Probabilistic Risk Assessment (PRA), Quantitative Risk Analysis (QRA) and Probabilistic Safety Analysis (PSA), is growing and can now be found written into regulatory rules. PQ in predictive modeling is attractive because of its grounding in probability theory and focus on numerical results.1 But, certain important safety related events are not probability-measurable which is problematic for risk-analytic methodologies that rely on PQ computations. Herein, we identify why the dynamics of available information play an essential role in governing the fidelity of PQ, and why PQ in the analysis of safety-critical protective systems is limited by the unmeasurability of certain critical events.2 We provide an historical example that provides a practical context for our observations. Finally we discuss the implications of measurability for regulatory decision-making governed by recent nuclear industry legislation advocating increased use of risk informed, performance-based regulation for advanced reactor licensing.3
A STEM Roadmap for Pre-Collegiate Engineering Students
Authors: Gharib Ali , Alyafei Nayef
Published: February 2023

In this paper, a comprehensive roadmap is presented that aims to provide an accessible and convenient resource for pre-collegiate students who are interested in science, technology, engineering, and mathematics (STEM) fields. The presented roadmap will be an effective guide to the students who are wishing to pursue STEM education independently in preparation for further studies or for personal development, but unsure of the specific activities and skills they require to kickstart them. The road map will also serve as a practical guide for teachers, counselors, and caretakers to guide and inform students interested in STEM tracks. This roadmap covers various recommended activities and courses that impart students with the necessary knowledge, experiences, and skills that are central in STEM studies and careers. An extensive literature review is conducted on various STEM programs from all around the globe that have a high impact on students in their respective fields, along with a recommended grade level for participation in said course/activity. Presented by this paper in each overview section are the individual advantages of each program with reference to skill acquisition, networking opportunities and even possible credits or accreditation detailed. Most of the presented programs are accessible online or in schools and STEM centers in most regions. Students who follow and complete this road map will not only be pre-equipped with the engineering knowledge before joining college but also will improve their position as a candidate for undergraduate or advanced level course selection.
Research on a New Analysis Method of Traction Performance for Variable-Diameter Wheels
Authors: Zeng Wen , Jiang Hui , Xu Guoyan , Gao Feng
Published: February 2023

Folded variable-diameter wheels used in planetary rovers can save spacecraft volume. Moreover, they can be expanded to improve their mobility on soft soil. However, only a single wheel foot was considered in previous researches on wheel-terrain interaction, which may be inaccurate. Hence, the cycloid motion equations for an unfolded variable-diameter wheel were introduced to obtain the shear displacement of any point on a wheel foot. Then, determining wheel-soil interaction regions was transformed into geometric relationship analysis. Therefore, the simplified model with a single wheel foot was established. Consequently, the traction efficiency achieved the peak when the range of wheel slip rates was 0.15∼0.35. The results shown that increased wheel diameter improved wheel mobility. For a greater sinkage, with the superposition of simplified model, the detailed model based on multiple wheel feet was built. This model got closer to real interaction status. The finite element analysis (FEA) results for the rolling wheel on soft soil were consistent with the theoretical hypotheses. Overall, the simplified model is very efficient, however, the detailed model is more accurate, which provides theoretical references for the control of optimizing wheel mobility. Additionally, this new analysis method developed here can also be applied to other expandable wheels.
Forestry Crane Immersive User Interface for Control and Teleoperation
Authors: Pizzagalli Simone Luca , Bondarenko Yevhen , Baykara Baris Cem , Niidas Alar , Kuts Vladimir , Kerm Margus , Otto Tauno
Published: February 2023

Timber industry is one of the most relevant economic sectors in Estonia. Automatization of forestry management and harvesting processes optimization are realities also in this specific domain. As much as in other industrial fields adopting the Industry 4.0 paradigm and core technologies, forestry management, log harvesting and the wood processing industry make use of state-of-the-art sensors, Digital Twins and advanced interfaces for the operators. The latter include Extended Reality solutions and remote-control making use of immersive head mounted displays (HMD). This works presents an innovative system for hydraulic forestry crane teleoperation making use of HMD and wide-angle camera stream. The system hardware is installed locally while the software, integrated in Unity, supports the operator in using the crane’s native joysticks and controller for the log loading operations. Additional virtual user interface and controls are included in the immersive view and accessible through the same controls and joysticks.
Recycling of Campus Solid Wastes Into a Low-Cost Green Instructional Equipment
Authors: Galindo Ronald M. , Obiso Jun-Jun A. , Caladcad Aian Rey A. , Tibay Edgar U.
Published: February 2023

A common problem in some State Universities and Colleges (SUCs) in the Philippines is the accumulation of campus solid wastes. A popular approach to minimizing this problem is the application of 3Rs (Re-use, Recycle, Reduce). These 3Rs are used by Cebu Technological University-Main Campus at Cebu City, Philippines, to foster Green Technology and promote a circular economy. The application of 3Rs is very timely since some classrooms are still traditional with no complete instructional equipment and devices to fortify instructional delivery. Hence, this paper’s ultimate intention is to develop low-cost, portable, and green instructional equipment through 3Rs adoption. This paper uses the instructional equipment from reusable campus solid wastes like glass, wooden pallets, tree branches, and swivel wheels. This equipment is fully loaded with the instructional materials and devices needed in the teaching-learning process. With its portability, the teachers can quickly transfer between classrooms with the instructional loads. In functionality assessments, several tests were conducted, like the stress analysis test, drop test, and system quality evaluation. Test results suggest that this instructional equipment is beneficial for instructional delivery in developing SUCs in the Philippines. Moreover, the equipment may not be solely used for classroom instruction during face-to-face classes but also can be usable during online classes.
Investigation of Tube Sheet Joining Through Hydroforging Process
Authors: Memon Shabbir , Nikhare Chetan P.
Published: February 2023

Tube-to-sheet joint expansion has been successfully used in HVAC industry for many years to avail better heat exchange between tube and fins (sheet). Because this system transports fluids under pressure, joining tube and sheet in heat exchangers is critical for all processing industries. The tube-sheet connection’s joining strength is critical because it directly affects plant safety. Tube-to-sheet joint strength is measured in terms of residual contact stress between the tube’s outer surface and the sheet’s hole surfaces. The joint integrity is affected by several design parameters, including the type of material and the initial radial clearance. The tube can be either deformed with or without an internal fluid pressure to create a joint. A commonly used process to deform the tube is hydroforming. However, hydroforming mostly uses the high pressure to deform the cross-section without dominantly use of axial length of the tube. In contrast, another category where the dominant use of axial length of the tube material is used to deform the section is termed as a hydroforging process. The use of a plastic deformation technique in hydroforging joining technology eliminates some of the limitations of existing joining technologies. The sheet deforms more strongly than the tube after the expansion tool is retracted. As a result, the tube and sheet come into direct contact.

This method allows for the joining of dissimilar materials and is also environmentally friendly. Fastened joints, welded joints, and adhesive joints are all examples of methods of joining that are comparable to each other in terms of their advantages and disadvantages. In this paper a tube to sheet joint will be studied during the hydroforging process. While the tube is pressurized with low pressure, the axial force will be applied to buckle the tube outward and around sheet. In the second stage the buckling region was compressed to make a joint. Two setting will be studied: intermediate joint (named: mid joint) and end joint. For this work a two-dimensional (2D) axisymmetric finite element model will be developed. The axial compression to create a buckling/folding in the tube and later joining with the sheet were studied. The mechanics of the buckling/folding was analyzed during the axial compression. The stresses induced at the interface were studied and resulted.
A Physics-Based Data-Driven Approach for Modeling of Environmental Degradation in Elastomers
Authors: Ghaderi Aref , Chen Yang , Dargazany Roozbeh
Published: February 2023

Elastomers are now commonly used in a number of industries, including aerospace, structure, transportation, shipbuilding, and automotive, due to their excellent workability, formability, and flexibility. During their activity, elastomers are subjected to harsh environmental conditions, which decreases their resilience. False predictions made early in their lives can have major financial and environmental implications. Elastomers’ performance and properties, such as strength, durability, and density, are influenced by chemical changes in these materials, known as degradation, which occurs over time. This process can alter the morphology of a polymer matrix as well as cause chain scission and cross-linking, resulting in different behaviors than that of the unaged material. To demonstrate the effect of thermaloxidative aging on the mechanical behavior of elastomers, several experimental and theoretical models have been proposed. In view of the large volume of experimental data available on micro-structural evolution in the course of aging, we propose a physics-based data-driven approach to overcome the shortcomings of both phenomenological and micro-mechanical models. This work presents a novel thermodynamically consistent, multiagent machine-learned model for predicting the constitutive behavior of cross-linked elastomers during environmental aging, such as thermo-oxidative and hydrolytic aging for various states of deformation. Single mechanism degradation changes the polymer matrix over time where it is causing chain scission, reduction of cross-links, and morphology change. To capture the idealized Mullins effect and permanent set due to the effect of single aging mechanisms on nonlinear mechanical responses of elastomers, we propose a data-driven model for simulating inelastic elements in a polymer matrix. By using a sequential order reduction, we were able to reduce the 3D stress-strain tensor mapping problem to a small number of super-constrained 1D mapping problems. To systematically classify such mapping problems into a few categories, an assembly of multiple replicated conditional neural network learning agents (L-agents) is used based on our recent work. Each category is represented by a different type of agent. The effect of deformation history, aging time, and aging temperature is captured by this model. The model is validated using a broad collection of data, ranging from our experimental results to data from the literature. In addition, thermodynamic consistency and frame independence are investigated. The most significant achievements of this model are its precision, simplicity, and prediction of inelasticity under various states of deformation. The model’s accuracy and simplicity make it a good option for commercial and industrial applications. Conveniently, due to the model modular nature, it can be expanded in the future to include viscoelasticity and non-isotropic formation for better precision.