bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dynamics of a Cantilevered Pipe Aspirating Fluid and Subjected to Reverse External Flow: the Effect of External Flow Confinement
Authors: Shaaban Ahmed , Chehreghani Mahdi , Misra Arun K. , Païdoussis Michael P. 
Published: February 2023

Abstract
The dynamics of a hanging cantilevered pipe aspirating fluid and simultaneously subjected to a partially confined external axial flow in the reverse direction has been investigated experimentally. A bench-top-size apparatus is used in this experiment consisting of a pressure vessel filled with water, a hanging cantilevered pipe and a shorter concentric outer rigid tube which is also vertically cantilevered. The flow configuration investigated in this paper is a simplified representation of the hydrocarbon storage mode of salt-mined caverns, which are large underground cavities used for storing hydrocarbons.
An experimental investigation has been conducted to determine the effect of the size of the annular gap on the onset of instability for various external to internal flow velocity ratios, Uo/Ui, ranging from 0.015 to 0.80. It was found that, for the range of flow velocity ratios investigated, the pipe loses stability via first-mode flutter. For the lower ratios of flow velocity, namely Uo/Ui = 0.015–0.06, the bifurcation diagrams show an increase in the root-mean-square (rms) amplitudes at three different ascending rates as the internal flow velocity Ui increased. In contrast, for high flow velocity ratio bifurcation diagrams, i.e., for Uo/Ui = 0.40–0.80, there is an increase in rms amplitude at a certain rate, followed by a diminished rate of growth as the internal flow velocity is increased further. The results demonstrate that the onset of instability occurs at relatively lower flow velocities as the Uo/Ui ratio is increased. Moreover, enlarging the annular gap has a stabilizing effect on the aspirating pipe. In comparison with the narrower rigid tube, with a wider rigid tube the signal power of the second-mode frequency was significantly amplified.
Development of a Holistic Data-Driven Detection and Diagnosis Approach for Operational Faults in Public Buildings
Authors: Alghanmi Ashraf , Yunusa-Kaltungo Akilu , Edwards Rodger 
Published: February 2023

Abstract
The data-driven approach prioritises operational data and does not require in-depth knowledge of system background; nevertheless, it requires considerable amounts of data. Obtaining faulty building data is a significant challenge for researchers. As a result, employing simulated data can be beneficial in data-driven faults detection and diagnosis (FDD) analysis because it is inexpensive and can run multiple sorts of faults with varying severities and time periods. The predominant implementation of FDD techniques within the building sector is done at the system level. However, as useful as system-level analysis is, typical buildings are comprised of multiple systems with their peculiar characteristics. Also, individualised system level-based analysis makes it challenging and sometimes impossible to visualise system-to-system interactions. However, there is a glaring underrepresentation of literatures that explore the development of whole building models that diagnose faults over the entire building energy performance sphere. Therefore, this paper presents a work to detect and diagnose building systems (HVAC, lighting, exhaust fan) faults in whole building energy performance within hot climate areas, using energy consumption and weather data. The detection process on the main building meter was conducted using LSTM-Autoencoders, and different multi-class classification methods were compared for the diagnosis phase. Moreover, feature extraction approaches were included in the comparison to quantify their performance in improving the diagnosis.
Design and Development of a Fish-Like, Soft Biomimetic Robot
Authors: Pai Nikhil , Contreras Esquen Andrea , Tekes Coskun , Amiri Moghadam Amir Ali , Tekes Ayse 
Published: February 2023

Abstract
Among the robotic systems, biomimetic robots performing fish-like locomotion have been the focus of much attention recently as there are many applications for swimming robots, including monitoring of underwater environments, detection of pollution, and disaster relief. This study presents the design and development of a biomimetic fish-like robot based on real carp locomotion. The robot has five main body parts including the head, soft neck, hinged body, compliant tail, and caudal fin. The head houses three ultrasonic sensors to guide the robot while connected to the body through two degrees of freedom (DOF) soft link resembling the neck vertebrate. The 2 DOF soft link enables the head to bend up, down, left, and right which is essential for controlling the soft robot’s direction. The body is connected to the soft tail using a quick return crank mechanism to actuate the tail. The tail integrates a soft tail and a rigid caudal fin. While all parts of the soft fish-like robot are 3D printed using polylactic acid (PLA), thermoplastic polyurethane (TPU), the mold is made from silicone rubber to waterproof. The ultrasonic sensors are utilized to detect obstacles so that the robot may maneuver around. The swimming pattern only for two-dimensional motion is tested in the air and underwater. According to the experimental results, the proposed robot better imitates the fish through its soft 2 DOF link and tail.
Design Strategies for Flywheel Energy Storage Systems in EV Fast Charging
Authors: Basaure Francisco , Mertiny Pierre 
Published: February 2023

Abstract
With rising numbers of electric vehicles to curb greenhouse gas emissions, mitigating strain on the electrical grid from EV charging, specifically fast-charging applications, has become a significant challenge, especially since adapting grid infrastructure is not only complex but costly. Long service life, high power charge capacity, and the ability to mitigate peak loads to the electrical grid are some of the requirements for energy storage systems (ESS) to support electric vehicle fast charging. In this context, interest in flywheel energy storage systems (FESS) has been growing in recent years due to the favorable power characteristics and lack of cycle aging that FESS offer over electrochemical ESS such as second-life batteries. Typically, flywheel design has focused on small-scale transportation and large-scale grid frequency regulation applications. The present paper presents design strategies for FESS in fast-charging applications, which signifies a promising and innovative approach for reducing the strain that fast EV charging imposes on the electrical grid. This study considers design strategies to achieve low material and fabrication costs, a high safety standard, and operational advantages.
Finite Element Analysis of the Critical Buckling Load in Hollow Microneedles With Lateral Support
Authors: Poudel Biswas , Ozsoy Istemi B. 
Published: February 2023

Abstract
Hollow microneedles provide minimum invasion to the skin and painless drug and vaccine delivery. However, there is a risk of fracture due to insufficient mechanical strength. The strength of microneedles might be increased by mimicking the bite of a mosquito. A mosquito has a proboscis that consists of a long needle (fascicle) surrounded by a protective sheath (labium). This sheath (labium) folds back as the fascicle pierces the skin, which provides lateral support to the fascicle. The lateral support increases the force that can be applied at the tip of the needle without buckling. In this study, the effect of lateral support on the buckling strength of a hollow microneedle made of chitin is analyzed numerically by using ABAQUS Finite Element Analysis software. The needle is modeled as a slender rod subjected to non-conservative (Beck) and conservative Euler loads simultaneously at the end. For a prescribed Beck load, the critical Euler load for buckling is obtained for various lateral elastic foundation stiffnesses. It is shown that the results of this computational study agree well with the analytical solution found in the literature. In addition, a three-dimensional finite element model is considered to study the effect of the needle tip geometry on the buckling and bending behavior of the needle.
Full-Field Operating Deflection Shape Measurement of a Structure With a Curved Surface Using a Three-Dimensional Continuously Scanning Laser Doppler Vibrometer System
Authors: Yuan Ke , Zhu Weidong 
Published: February 2023

Abstract
This study proposes a novel general-purpose 3D continuously scanning laser Doppler vibrometer (CSLDV) system to measure 3D full-field vibration of a structure with a curved surface in a non-contact and fast way. The proposed 3D CSLDV system consists of three CSLDVs, a profile scanner, and an external controller, and is experimentally validated by measuring 3D full-field vibration of a turbine blade with a curved surface under sinusoidal excitation and identifying its operating deflection shapes (ODSs). A 3D zig-zag scan path is proposed for scanning the curved surface of the blade based on results from the profile scanner, and 6scan angles of mirrors in CSLDVs are adjusted based on relations among their laser beams to focus three laser spots at one location, and direct them to continuously and synchronously scan the proposed 3D scan path. A signal processing method that is referred to as the demodulation method is used to identify 3D ODSs of the blade. The first six ODSs from 3D CSLDV measurement have good agreement with those from a commercial 3D SLDV system with modal assurance criterion values larger than 95%. In the experiment, it took the 3D SLDV system about 900 seconds to scan 85 measurement points, and the 3D CSLDV system 115.5 seconds to scan 132,000 points, indicating that the 3D CSLDV system proposed in this study is much more efficient than the 3D SLDV system for measuring 3D full-field vibration of a structure with a curved surface.
Experimental Characterization of Surge Cycles in a Centrifugal Compressor
Authors: Serena Alberto , Bakken Lars Eirik 
Published: February 2023

Abstract
Compressor operation under off-design conditions generates undesirable instabilities and detrimental effects both on system stability and machine reliability perspectives.
The main objective is to provide a suitable approach and proper description of the flow and machine behaviour in the surge inception to reverse flow operating area, yielding valuable data for a deeper understanding of the underlying flow mechanisms, useful for tuning prediction models.
A literature review, with a particular focus on the experimental method, test rig layout, and instrumentation when handling with reverse and pulsating flow, is presented.
The need for a clear setting of test procedure and key parameters measurements to detect unsteady phenomena under transient conditions, with instrumentation available for field operation and separating compressor behaviour from system response, is specifically addressed. To perform this, the experimental technique is employed and described in detail in this paper, while performance modeling validation, object of parallel studies, will be presented in future publications.
The test facility allows the required responsive dynamic measurements; tests cover a broad range of flow rates and two different rotational speeds. The aim is to specifically approach the instabilities sections and characterize the positive slope area, featuring rapid cycles between surge line and zero-flow.
The results, presented as pressure and flow fluctuations, play a key role for the simulation of more complex dynamic scenarios. This wide collection of test data is of great value for a further understanding of the phenomenon, the development of reliable surge onset prediction models and control strategies.
Unsteady Dynamics of a Low Aspect Ratio Mixing Layer
Authors: Eckstein Adam , Banko Andrew , Benson Michael 
Published: February 2023

Abstract
This work examines the temporal dynamics in the near-field of a low aspect ratio mixing layer. Using Planar Laser Induced-Fluorescence (PLIF), we investigate mixing dynamics between a rhodamine dye contaminated stream and a clean water uncontaminated stream at different velocity ratios. An in-situ calibration experiment is performed to verify the linearity of the image intensity with rhodamine concentration and to account for spatial variations in laser sheet intensity. The mixing dynamics are analyzed for velocity ratios ranging from one to three, defined as the ratio between the bulk velocity in the small channel to the bulk velocity in the large channel. This range yields mixing layer Reynolds numbers based on the velocity difference, channel width, and kinematic viscosity of water ranging from zero to approximately 1,600. The average and transient properties of the mixing layer are analyzed. The average concentration distribution is presented to quantify the spreading rate of the mixing layer. Of particular interest is the intermittency of the concentration time series at the channel centerline and the nominally clean and contaminated streams, both of which are related to the formation of large scale vortical structures.
Nonlinear Electro-Mechanical Impedance Spectroscopy for Comprehensive Monitoring of Carbon Fiber Reinforced Composite Laminates
Authors: Lu Runye , Shen Yanfeng 
Published: February 2023

Abstract
This paper presents a Nonlinear Electromechanical Impedance Spectroscopy (NEMIS) methodology for the comprehensive monitoring of carbon fiber reinforced composite (CFRC) laminates. This method can obtain structural impedance spectra and capture nonlinear ultrasonic features for damage detection, combining the merits of the conventional EMIS and the nonlinear ultrasonic techniques. A comparative illustration between the conventional EMIS and NEMIS is presented. Various damage types and damage mechanisms of CFRC laminates are reviewed. Numerical investigation on a reduced-order 1-D Contact Acoustic Nonlinearity (CAN) model are conducted to demonstrate the chirp-induced nonlinear features. Furthermore. a finite element (FE) model is established to verify the feasibility of the NEMIS for damage detection. The macro-scale damage types are modeled by the changes of material properties, while the incipient damage like delamination is simulated by setting the contact interfacing condition between the laminate debonding areas. Correspondingly, the chirp-based impedance spectra are employed to detect the macro-scale damage via the deviation of resonance peaks, while the nonlinear features, such as higher harmonics and wave modulation are utilized to monitor the delamination. Two damage indices are developed to quantify the severity of both the macro and incipient damage. This paper finishes with conclusion and suggestions for future work.
Prediction of the Generation of Intergranular Cracking in Stainless Steels Under Creep Loading at Elevated Temperatures
Authors: Suzuki Ken , Nakayama Koki , Nakayama Ayumi , Tezuka Shogo , Miura Hideo 
Published: February 2023

Abstract
Initiation mechanism of intergranular cracking in SUS316L under creep loading at elevated temperatures was investigated quantitatively by applying electron back-scatter diffraction (EBSD) analysis. It was found that intergranular cracking started to appear by 40% of the normalized lifetime of the steel and the cracked grain boundaries were close to perpendicular to the direction of the applied load and the Schmid factor of one of the grains which consisted of the cracked grain boundaries was larger than 0.43. In addition, the difference of the Schmid factor between the nearby grains was large. Not only dislocations but also vacancies were found to accumulate faster around the cracked grain boundaries. The reason for the accelerated accumulation was attributed to the local mechanical stress concentration around the grain boundaries, which was caused by the large lattice mismatch between the nearby grains. The degradation process of the crystallinity of the grain boundaries was continuously monitored by using the image quality (IQ) value obtained from the EBSD analysis. The degradation process was analyzed by using the modified Arrhenius equation, in which the effective activation energy of the damage accumulation decreased locally with the large strain around the cracked grain boundaries. The local activation energy was confirmed to be more than 30% lower than that obtained under the thermodynamically stable condition.
Strain-Induced Change of Adsorption Behaviour of Gas Molecules on Graphene Analyzed by Density Functional Method
Authors: Yin Meng , Qiao Xiangyu , Zhang Qinqiang , Suzuki Ken , Wang Lei 
Published: February 2023

Abstract
In Aging society, health monitoring sensors are indispensable for reliable daily care. Graphene has been suggested to be capable of detecting gas compositions in a person’s breath to diagnose sickness down to the ppb-level, because of its large surface-to-volume ratio and high carrier mobility. The resistance of graphene was found to change clearly due to the adsorption of gas molecules such as NH3, NO2, and so on. When plural different molecules adsorb on graphene at the same time, however, it is impossible to identify the adsorbed molecules individually. The development of the selectivity of the adsorbed molecules, therefore, is indispensable for applying this gas-adsorption-induced resistance change of graphene to a health monitoring sensor.
In order to improve the selectivity, the interaction between graphene and various gas molecules (CO, H2O, and NH3) with and without applied mechanical strain were calculated using the density functional theory (DFT) method. It was found that the adsorption behaviour of gas molecules on graphene changed under the application of strain and shows different dependence of the adsorbed gas species. Some gas molecules such as CO and NH3 gradually desorbed, while other gas molecule such as H2O, on the contrary, adsorbed more stably under tensile strain. This work revealed that the selectivity could be improved by applying the appropriate mechanical strain to graphene, paving the path for a graphene-based gas sensor in biosensing applications.
Stress Concentration Mechanism in Superconducting Coil Quench Phenomenon by Large-Scale Finite Element Analysis
Authors: Hisakuni Yousuke , Kano Akira , Uehara Hideaki , Monda Tomoko , Hirokawa Junko , Nishimura Osamu , Hirohata Kenji , Ito Toshinobu , Takami Shohei , Sato Kiyokazu 
Published: February 2023

Abstract
A quench is the transition from a superconducting state to a normal conducting state. Elucidating the mechanism of quenching caused by mechanical disturbances (training quench) requires a detailed understanding of the stress state in the coil during excitation. In this study, we developed a large-scale analysis method that can precisely analyze where strain energy is concentrated and loss energy is generated due to thermal stress and electromagnetic force in superconducting coils by considering the detailed structure of superconducting wires and the wire alignment disorder caused by constraints during winding. The results showed that strain energy in the resin is concentrated in the region of overlap between the strain energy distribution caused by the macroscopic deformation of the coil and the geometrically inhomogeneous region, including the wire transfer zone. Furthermore, comparative verification using acoustic emission measurements to determine damage locations suggests that quench is also concentrated at the transfer zone in the actual coil, thus demonstrating the validity of the analysis. A sub-model of the area around the transfer zone, which was found in the large-scale analysis, was created, and crack propagation analysis was conducted using the phase-field method. Crack propagation in the resin and increased deformation of the wire due to weakening of the supporting rigidity of the wire caused by the crack propagation were observed.
Numerical Investigation of Ultrasonic Phased Array Reverse Time Migration Technique Considering Spatial Wave Characteristics
Authors: Zhou Shulong , Shen Yanfeng 
Published: February 2023

Abstract
This paper presents a systematic numerical research on ultrasonic phased array reverse time migration technique for damage evaluation in bulk materials. In this study, a thick aluminum bulk is used as the target structure to be tested, and an ultrasonic phased array composed of piezoelectric elements and damping blocks is prosed as the transducers for generating and receiving elastic waves. Firstly, a Finite Element Model (FEM) of a pair of transducers is established to study the wave generation and reception performance. In particular, the suppression effect of different backing material parameters (damping ratio, thickness, implementation details) on the piezo-elements to absorb excessive resonant vibrations is investigated, in order to send out and receive spatially squeezed mechanical pulses into the target medium. Then, a full-scale FEM is established with the complete probe set and typical structural damage types to understand the wave propagation and its interaction with damage. Both longitudinal (L) and shear (S) waves are studied, while they interact with a hole and cracks with different orientations with respect to the incident wave direction. Finally, the reverse time migration algorithm is further developed by considering the spatial wave characteristics. The amplitude variation along the propagation distance is taken into account to form a time/space-gain compensation function to improve the damage imaging quality and sensitivity, especially for far field damage sites. At the same time, the imaging algorithm is tested for the single L-wave, the single S-wave, and the fused LS-wave scenarios. It was found that the combination of L-mode and S-mode can significantly improve the damage imaging results. This numerical investigation may lay a solid foundation for the development of ultrasonic phased array technique for non-destructive evaluation (NDE) of bulky materials. This paper ends with a summary, concluding remarks, and suggestions for future work.
Influence of Surface Roughness on Heat Transfer and Flow-Induced Vibrations of a Circular Cylinder
Authors: Ali Ussama , Islam Md. , Janajreh Isam 
Published: February 2023

Abstract
In this study, two-dimensional numerical analysis was done to investigate the influence of surface roughness on the heat transfer and flow characteristics for a circular cylinder subjected to crossflow. Numerical solution of the URANS and energy equation was sought using Ansys Fluent for the transient analysis at Reynolds number of 100. The roughness was induced in the cylinder surface by considering the sand surface roughness model. Four levels of roughness were studied with the roughness coefficient (Ks/D) varying between 0.01 and 0.06. The cylinder was allowed to move in transverse as well as streamwise direction to study the two-degree of freedom motion. The reduced velocity was varied in the range of 1–10, covering the region with maximum amplitude of vibration. The cylinder was heated at 300°C above the freestream fluid temperature. The numerical model was validated with the results from the literature. The analysis was done in terms of vorticity and temperature contours, Nusselt number, Strouhal number, and lift and drag coefficients. The results indicated that the surface roughness affected the flow characteristics and heat transfer in such a way that Strouhal number increased, while the lift and drag coefficients and Nusselt number decreased with the increase in the surface roughness. However, the effect of Nusselt number was much higher in comparison to the effect on the Strouhal number and lift and drag coefficients.