bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thermal Behavior of PCMs During Phase Transitions With Phase Change Hysteresis: Experimental Setup Development and Problems of Model Validation
Authors: Zálešák Martin , Charvát Pavel , Klimeš Lubomír , Pech Ondřej , Bouchal Patrik 
Published: February 2024

Abstract
Various models and approaches for phase transitions of phase change materials (PCMs) have been proposed in recent years. However, many of these models lack validation with experimental data, particularly the models for phase change hysteresis (PCH) and incomplete (partial) phase transitions. To address this issue, an experimental setup was designed, assembled and tested for potential validation of numerical models. The experiments involve monitoring of the heat flux and the temperature distribution in a PCM contained in a rectangular cavity with a heated/cooled wall. Peltier cells are used to introduce positive or negative heat flux - heating and cooling of the PCM. The first sets of experiments were conducted with the RT35HC paraffin-based PCM. The ultimate goal of the experiments is to provide experimental data for solving inverse heat transfer problems, specifically the identification of the relationships between the enthalpy and temperature during complete and incomplete phase transitions of a PCM. The results suggest that in order to properly account for the influence of natural convection in liquid PCM, a more appropriate experimental setup that avoids its effects or a more suitable modelling approach is required.
Mechanical Characterization of Yucca Plant for Potential Biomimetic Applications
Authors: Shaw Rickelle , Robertson Kyle , Vargas-Silva Gustavo , Mixon Daryl , Jawaharlal Mariappan 
Published: February 2024

Abstract
Hesperoyucca Whipplei (HW), commonly known as the chaparral yucca, is a species of yucca native to the southwestern United States, particularly California and Arizona. This plant has adapted to thrive in dry, arid conditions, making it an interesting subject for studying the mechanical properties of its physical structures.
Research has shown that the chaparral yucca has distinctive physical and structural characteristics that allow it to withstand external forces and environmental stresses. For example, the yucca’s leaves and stems are composed of fibrous tissue that provides both stiffness and flexibility, allowing them to bend and resist breaking under wind and other physical stresses.
For this paper, experiments were performed to establish the mechanical properties of HW with a focus on understanding its distinctive physical and structural characteristics. Tensile tests were conducted on different components of the plant, including whole leaf samples, fiber bundles, braided fibers, and single fibers. Similarly, the outer bark of the stalks underwent 3-point bending testing. Studying the mechanical properties of HW can provide valuable insights into the plant’s adaptation to its environment and inspire new innovations in materials science and engineering.
Improving Fuel Efficiency of a Boat by Retrofitting Propeller Modelling and Experimental Validation
Authors: Bonthu Satish , Unnthorsson Runar , Sigurbjarnarson Hordur , Gunnarsson Stefán 
Published: February 2024

Abstract
This paper presents the successful retrofitting of an old whale-watching boat incorporating a larger propeller and a new reduction gear. The retrofit resulted in an impressive, 30% improvement in fuel efficiency across the entire operating range of the propulsion system. This significant improvement directly translates to a reduction in carbon emissions, underscoring the project’s importance for further investigation. Given that the propeller contributes to 80–90% of the vessel’s fuel consumption, a detailed analysis of the hydrodynamic performance improvement is warranted. To address this, a cost-effective and efficient computational fluid dynamics (CFD) approach is proposed to qualitatively connect the observed field performance of the vessel with the mechanical performance of the new propeller. The study highlights the accuracy of this approach in realistically predicting the field performance of both the old and new propellers under different operating conditions derived from sea trials. In conclusion, this study demonstrates the potential for retrofitting existing vessels with improved propulsion systems, resulting in increased fuel efficiency and reduced carbon emissions.
A Solution to an Inverse Heat Transfer Problem With Phase Change by Means of Meta-Heuristics and Artificial Neural Networks: A Comparative Study
Authors: Klimeš Lubomír , Kůdela Jakub , Zálešák Martin , Charvát Pavel 
Published: February 2024

Abstract
Many engineering problems involve heat and mass transfer. A typical solution procedure for such a problem represents the determination of thermal behaviour and thermal response of a system under specific conditions, including thermal conditions (initial and boundary conditions) and material-related parameters (thermo-physical properties). Such a problem is referred to as a direct problem. In certain cases, however, some of these conditions or parameters are not known. Instead, information about the thermal behaviour is available. This is the case in which an inverse heat transfer problem has to be solved. Such a problem is actually a data-fitting and optimization task since conditions and parameters, which minimize the error between actual and prescribed data, are searched indirectly. A number of gradient-based methods to inverse problems have been developed in the past. However, they suffer from some disadvantages, including proneness to get trapped in local optima or a low performance in large-scale problems. This is the reason why so-called soft computing methods have experienced great development in recent years. In this paper, seven meta-heuristic algorithms and one algorithm based on an artificial neural network (ANN), referred to as an LSADE algorithm, were applied to the solution of an inverse heat transfer problem with phase change. The problem involved an inverse identification of parameters of an effective heat capacity function, which is a common technique used in phase change modelling. An air-PCM heat exchanger for latent heat thermal energy storage and solar air heating was used as a study case. Results obtained within the scope of the study indicate that the ANN-based LSADE algorithm significantly outperformed other meta-heuristic algorithms, which makes it a very promising tool for the solution of similar kinds of problems.
Basic Research on Music Prescriptions - Second Experiment With Classical Music
Authors: Hishida Hirotoshi , Hashimoto Shigehiro , Saeki Kaito , Kono Hikaru , Hishida Keiko 
Published: February 2024

Abstract
The authors assume that the stress state can be expressed by a value, SMB, and are trying to develop a method to change the value in an appropriate direction by music. This paper compares the results of the music therapy experiment conducted in 2022 with those in 2020. Subjects are recruited and classified into four groups according to whether they know the pieces played and whether they like the music. Some subjects wear the pulse oximeter throughout the concert. Other methods are employed to measure the stress states of all subjects at the beginning, the intermission, and the end of the concert.
Based on the experiment, the possibility of prescribing classical music to patients is recognized. The same music has different effects on the subjects, depending on the type of music and the subject’s characteristics such as gender and whether he/she likes the music. The effects also differ depending on the piano player. In other words, prescribing music would not be simply selecting songs according to the symptoms.
In the future, the music database will be grown up and the experimental methods using public concerts will be improved. Some of the stress measurement methods employed in this experiment may be combined to determine SMD.
On the Delamination of CFRP and Epoxy Adhesive Interface Using Laser Shock Adhesion Test (LaSAT)
Authors: Takagi Aoi , Hosoya Yuichi , Yasuda Shotaro , Ogata Kazuma , Takeda Tomo , Yonezu Akio 
Published: February 2024

Abstract
For a reduction of aircraft structural weight is strongly demanded, Carbon Fiber Reinforced Plastics (CFRP) has been widely used, since it has enormously lightweight and excellent specific strength, compared to metallic materials. In addition, for the joining technology of dissimilar materials, adhesive bonding has been actively developed instead of mechanical fastening such as bolts and rivets. In addition to understanding static mechanical characteristics, the development of advanced transport aircraft needs to clarify dynamic behavior and impact response. However, there are few studies on adhesive bonding strength of CFRP under ultra-high strain rate which ranges from 106 to 107 1/s. To achieve the purpose of bonding strength evaluation under such high strain rate, this study employed Laser Shock Adhesion Test (LaSAT) to evaluate the adhesive strength of CFRP and epoxy resin adhesive under high strain rate. LaSAT, which employs a laser ablation, induces strong shock wave, resulting in interfacial delamination under high strain rate. When the tensile stress wave reaches the critical strength, the interfacial delamination occurs. Moreover, CFRP laminate can change its mechanical property by changing the direction of carbon fiber in each stacking sequence. This study prepared two types of CFRP, i.e. UD-CFRP (Unidirectional fiber reinforcement composite) and QI-CFRP (Quasi-Isotropic composite). Using these two types of CFRP, this study investigated the effect of CFRP stacking sequence on the interfacial delamination morphology due to LaSAT. The delamination morphology and bonding strength of CFRP/epoxy resin adhesive were investigated.
Piezoelectric Energy Harvesting Array of Tethered Bodies Utilizing Flow-Induced Vibrations
Authors: Fam Marina , Roussinova Vesselina , Stoilov Vesselin 
Published: February 2024

Abstract
This paper investigates a mechanical system utilizing flow-induced vibration (FIV) of oscillating bodies in a steady flow. Multiple tethered bluff bodies are elastically mounted and arranged in three different staggered configurations. The hydrokinetic steady water flow is converted to mechanical oscillations via FIV, and the vibration energy is further converted to electrical energy by piezoelectric strips. To achieve the optimal design of the oscillating system, a series of experiments are performed to examine the effect of the optimal spacing between the oscillating bodies. Furthermore, the effect of the flow Reynolds number is investigated in the laboratory conditions for each configuration. The amplitudes and frequency of the oscillations of the mechanical system are analyzed from the measured voltage with the use of a data acquisition system. Furthermore, information for the dominant frequencies, spectra, and power levels is extracted from each individual body to examine the sheltering effect and estimate the power generated by each array configuration. The measured oscillations show that the sheltering effect is greater in the array’s center than at the edges. Moreover, the current experiments showed that the vibrational characteristics of each tethered body are close to the lock-in branch, where the body’s natural frequency matches the shedding frequency as closely as possible.
A Water Saving Device for Home Usage
Authors: Romero Navarrete José Antonio 
Published: February 2024

Abstract
An economy water-saving pedal valve is proposed in this paper, to be used at homes for controlling the water supply at sinks. The reduced cost derives from its conceptual design, which considers standard commercial components, while involves inexpensive manufacturing and assembly processes. Comparative testing of the proposed valve with respect to standard water control devices based upon standard hand-operated faucets, reveals water savings on the order of 50%, for a sample of 10 users. Such saving water characteristic adds to the hygienic quality of the device, due to its hands-free operation. The massive use of this device could represent daily savings of several hundreds of cubic meters of drinking water in a medium size city of 280000 inhabitants.
Machine Learning Based Search for Access Points in Anomaly Detection Model
Authors: Naik Vishnu Gangadhara , Fabarisov Tagir , Morozov Andrey 
Published: February 2024

Abstract
Heterogeneous systems are characterized by a high degree of complexity that poses challenges to conventional anomaly detection methods. One of the challenges is the production of large amounts of data where Deep Learning based Anomaly Detection Models (DLAD) have been demonstrated to outperform conventional techniques in detecting anomalies. However, DLAD models require the manual selection of Access Points, which are specific points in a system from which the training data is recorded. The selection of Access Points is a critical task that can significantly affect the performance of the anomaly detection models. It requires domain knowledge and expertise in the intricacies of the system, which is difficult to acquire and prone to human errors. As the size of the system grows, selecting Access Points becomes increasingly challenging.
In this paper, we propose a new machine learning-based algorithm called the Access Point Search Algorithm (APSA). The aim of APSA is to automate the task of finding the optimal set of Access Points that can aid DLAD models in detecting anomalies in a particular system. The algorithm utilizes a special error detector that dynamically takes in multiple signals and forecasts the signal values. The objective of finding the optimal set of Access Points is formulated as a feature selection problem, which is supervised using a binary variant of the Grasshopper Optimization Algorithm (GOA). We demonstrate the feasibility and effectiveness of the proposed algorithm by deploying it in a Simulink model.
We illustrate the reliability of the proposed algorithm by feeding the signals from all the Access Points in the set provided by APSA into the DLAD model one by one. The reliability is further discussed by carrying out a fault injection experiment on the Simulink model. The proposed algorithm was able to reduce 80% of the Access Points. The Access Points selected by APSA showed a high probability of detecting anomalies over the Access Points that were not selected. The results suggest that the proposed algorithm can efficiently and effectively select the optimal set of Access Points for DLAD models to detect anomalies in component signals. It offers a promising solution to automate the tedious and error-prone task of selecting Access Points, thereby reducing the domain knowledge and expertise required.
Workspace Specific Robot Arm Design
Authors: Parhofer Christoph August Wilhelm , Pancheri Felix , Rehekampff Christoph , Lueth Tim Christian 
Published: February 2024

Abstract
In this paper, a new design method for serial robot arms is presented. The method aims to reduce the number of joints by customizing the connecting shape of a robot arm between its joints. For that, the classically straight shape of a robot arm is redesigned, depending on the workspace with its obstacles, the motion path and the location of the robot base. The focus of this work is the automated customization of such arms in MATLAB, by designing individual extrusion splines for each arm, in each environment. The design methodology is exemplarily implemented and validated on an in-house developed 4-DoF robot arm in different workspaces. For this purpose, the originally straight arm structures of the 4-DoF robot arm between the 2nd and 3rd joint as well as the 3rd and 4th joint are removed and replaced by the reshaped arm structures. To easily produce and change the arms in each environment at low cost FDM printing and snap fittings for the arm connections are used. Two examples of such reshaped arms are shown in this work for validation.
Evaluation of the Impact of COVID-19 on the Automotive Industry: Analysis of the Effects of Confinement on a Hybrid Vehicle
Authors: Carrera Rivera Gabriel , Espinoza-Andaluz Mayken , Ordóñez-Saca Brayan , Santana-Villamar Jordy 
Published: February 2024

Abstract
The COVID-19 pandemic has significantly impacted several aspects of daily life, including transportation. The transportation sector influences pollutant gas emissions and the economies of society. One solution to reduce emissions is to use hybrid or electric vehicles, which employ clean technologies and improve efficiency. This article analyzes production stoppages, decreased demand due to mobility restrictions, and interruptions in the supply chain for vehicle production during the pandemic. The effects of these variables on sales and production of hybrid vehicles in Ecuador and worldwide are also examined. The article presents a study on the damage caused by the disuse of a vehicle within a high-voltage hybrid charging system. It also proposes an analysis of a high-voltage battery set’s recovery and maintenance processes in a hybrid vehicle. Using test benches to analyze battery cells, categorizes the cells of the high-voltage battery body according to their state of charge. The results show that the vehicle’s high-voltage charging system was affected during the pandemic, with more than 50% of its cells in lousy condition. However, some cells can still undergo balancing and maintenance processes to form another set of cells for a high-voltage battery.
Origami-Inspired Cylindrical Structures for Energy Absorption in Aerospace Applications
Authors: Hussain Khaja Fayaz , Cantwell Wesley J. , Khan Kamran A. 
Published: February 2024

Abstract
The current work emphasizes on hybridization of the cylindrical curved crease origami structure with high energy absorbing state-of-the-art cellular lattices mainly, the plate, truss, and hourglass lattices, with a motive to enhance the energy absorption capability of the structure. A novel non-hybridized curved crease cylindrical origami namely star curved and three of its hybridized counterparts, star curved plate (S.C.P), star curved truss (S.C.T) and star curved hourglass (S.C.HG) are proposed in the paper and the effect of hybridization on the energy absorption properties was investigated. Additionally, the deteriorating effect of moisture on the mechanical properties and energy absorption characteristics was emphasized and it was observed that the dried samples outperformed the as-fabricated samples. The structures were designed with the help of CAD software and fabricated via fused filament fabrication (FFF) due to its capability of providing geometrical flexibility and precise control of micro architecture and dimensions using Nylon polymer. The structures were later tested on an Instron compression testing machine to obtain the force-displacement data for further processing. The results substantiate the validity of the hybridization approach as the specific energy absorption of the non-hybridized structure was enhanced from 4 kJ/kg to 6.6 kJ/kg. Moreover, the mechanical properties like peak strength and elastic modulus were remarkably improved from 1.3MPa to 6.5 MPa and 41 MPa to 290MPa respectively. The proposed approach leads to an increase in possibilities for improving the origami-inspired structures in terms of specific energy absorption for situation-specific applications and when incorporated into sandwich panels, the performance of these structures can further be explored.
An Investigation on the Aerodynamic Characteristics of An Electroactive Membrane
Authors: Ojo Oluwatosin , Su Ji , Chakravarty Uttam K. 
Published: February 2024

Abstract
Dielectric elastomer membranes are electroactive polymers that can generate large linear actuation strains likened to muscles when acting as an actuator. These membranes can both release and store elastic energy due to the elasticity of the materials when acting as an elastomer. Unique mechanical properties like low modulus, flexibility, and electrical induced deformation make the dielectric elastomer membrane an ideal material that can mimic the resonant actuation found in insects and winged mammals while simultaneously solving the complex transmission mechanism found in conventional unmanned aerial vehicle designs. The objective of this study is to computationally evaluate the aerodynamic characteristics and response of the dielectric elastomer material, VHB 4910. The result from this analysis validates the experimental aerodynamic responses from the material’s wind tunnel testing. The computational environment with flow conditions maintained at a low Reynold’s number suitable for the control of flow in micro air vehicles is used to analyze the fluid-structure interaction of the models. The standard and explicit model coupled with the computational fluid dynamic model of the surrounding air creates a cosimulation analysis. As the angle of attack increases, the coefficient of lift experiences a rise until it reaches a critical value, while the coefficient of drag also goes up.
Warehouse and Logistics Ergonomics Optimization Through Real-Time Evaluation of the NIOSH Index
Authors: Lanzoni Daniel , Negrello Francesca , Vitali Andrea , Regazzoni Daniele , Catalano Manuel G. , Rizzi Caterina 
Published: February 2024

Abstract
Logistic activities can cause long-term musculoskeletal problems due to repetitive and incorrect movements, heavy loads, and uncomfortable positions. Ergonomic evaluations are conducted to prevent these risks, optimize workstations, and work processes. Some studies use automatic evaluation of ergonomic indices or frameworks for optimizing workstations and logistics reorganization. However, optimization is often disconnected from real-world case studies. This research work validates a new approach that integrates an automatic ergonomic evaluation and optimization in real-world scenarios, comparing this analysis with traditional manual evaluation method. Our approach is applied to a real logistics case study using a wearable motion capture system and an interactive interface that displays the Digital Twin of the analyzed task. Results show that our approach provides a more accurate evaluation of the ergonomics and an evident time-saving.
Automated Design of Custom Printed Circuit Board Enclosures With Integrated Cooling Capabilities
Authors: Pancheri Felix , Sun Yilun , Parhofer Christoph August Wilhelm , Rehekampff Christoph , Zhang Dingzhi , Lueth Tim C. 
Published: February 2024

Abstract
Power electronics or processing units generate significant amounts of heat during operation, which must be dissipated. At the same time, there is a trend towards the production of small quantities of individual printed circuit boards. Thus, more and more individual cooling solutions for printed circuit boards are required. Conventionally, individual components on printed circuit boards are cooled using commercially available heat sinks. Housing the printed circuit board inside an enclosure can affect the cooling performance of heat sinks. If a printed circuit board is unusually shaped or a particularly compact design is required, suitable prefabricated enclosures are not necessarily available. In these situations, enclosures designed specifically for an individual printed board can be used. Custom designed enclosures made of materials with sufficiently high thermal conductivity can serve directly as heat sinks. In this work, an automated design process of custom dual-purpose enclosures for printed circuit boards with integrated cooling capabilities is proposed. The automated design process is based on the Solid-Geometry (SG) Library, a MATLAB-toolbox for automated design of surface models and optimized for additive manufacturing methods. Based on a geometry model of the printed circuit board, a suitable enclosure is automatically designed. In addition, several design examples are also presented to demonstrate the feasibility of the proposed approach.