Experimental Aspects Research Articles

The shock wave evolution of the laser-induced breakdown under non-spherical symmetry using a 1064 nm nanosecond laser

In acoustics-related interdisciplinary areas, the shock wave of laser-induced breakdown has garnered significant attention. However, research on the propagation of shock waves in non-spherical symmetry is insufficient in both theoretical and experimental aspects. This paper aims to thoroughly study the evolution of underwater shock wave directivity by employing the method of shadowgraph. The shock wave front is determined by the dark fringes in the shadowgraph image and the normal propagation speed of the shock wave is calculated using Huygens principle. Subsequently, normal propagation speed is converted to pressure in different directions by employing the equation of state of the medium. It has been found that the spherical plasma produces an isotropic shock wave, whereas filamentary plasma generates a highly anisotropic one. To evaluate the anisotropic property of the shock wave, we introduce pressure directivity, which is defined as the pressure at any direction normalized by the maximum value. The temporal evolution of shock wave pressure directivity is obtained based on the shadowgraph images. In the case of filamentary plasma, there is a sudden transition of the pressure directivity in the axial from 40 ns to 165 ns, after which the pressure directivity is consistent with the hydrophone measurement. Based on the moving breakdown model of the plasma and the superposition principle, we propose a theoretical model to explain the experimental result of the pressure directivity. The outcome of our model exhibits considerable consistency with the experiment.

From Experimenting with Property to Experimenting on Place: A Rejoinder to Migozzi and Safransky

AbstractThis rejoinder engages with the commentaries on my article on ‘Digital experiments with landed property’ from Julien Migozzi and Sara Safransky. In my response, I share my reflections on the valuable provocations and interrelated themes offered in these generous commentaries. First, I argue that an especially distinctive aspect of digital experiments with landed property is the volumetric property relations they are generating. Second, I attend to subjectivities cultivated within and against digitised property relations, and how they relate to structures of power. Third, I extend my thinking on the glitchiness and fallibility associated with processes of experimentation.

Experimental and theoretical investigation of shear lag effect in twin box‐shaped composite girders of long‐span cable‐stayed bridges

AbstractSteel‐concrete composite box girders offer notable advantages such as high stiffness, excellent torsional performance, and light self‐weight, making them prevalent in large‐span bridges, particularly in cable‐stayed configurations. However, a persistent challenge arises from the shear lag effect in the concrete slab within the flanges induced by shearing interactions between the webs and flanges. Limited attention has been devoted to investigating the experimental and theoretical aspects of shear lag in long‐span cable‐stayed bridges with twin box‐shaped composite girders. This research addresses this gap by designing a segmental scale twin box‐shaped composite model specimen to simulate the cable spacing of the main girder in a cable‐stayed bridge, specifically targeting the shear‐lag effect. The study successfully captures the non‐uniform distribution of cross‐sectional strain in the top concrete slab. Subsequently, analytical strain solutions for the composite girder under mid‐span concentrated load and axial load are derived using the energy variation method. The theoretical model's applicability is then calibrated against experimental results. The investigation extends to the in‐situ testing of the Chibi Yangtze River Bridge, the world's largest steel‐concrete composite girder cable‐stayed bridge, boasting a main span of up to 720 m. An established finite element (FE) analysis model for the Chibi Yangtze River Bridge simulates the transverse stress distribution under typical construction conditions of CC6. Comparative analyses between the simulated results, calculated values from elementary beam theory, and the theoretical model against field‐measured values reveal that the FE model provides a more accurate estimation of the shear lag effect in the concrete slab. Notably, the FE model effectively reflects the bridge's characteristics and serves as a baseline for subsequent studies. This comprehensive investigation contributes significantly to the understanding and analysis of shear lag phenomena in twin box composite girders of cable‐stayed bridges. The integration of experimental, analytical, and construction site validations establishes robust tools for engineering design and the construction of safe and serviceable cable‐stayed bridges. The research augments knowledge regarding shear lag behavior and underscores the necessity to appropriately consider its effects in bridge analysis and design.

Non‐Volatile and Gate‐Controlled Multistate Photovoltaic Response in WSe2/h‐BN/Graphene Semi‐Floating Gate Field‐Effect Transistors

AbstractSemi‐floating gate field‐effect transistors (SFG‐FETs) based on 2D materials have received much attention due to their unique optoelectronic characteristics, potential applications in near‐memory computing and constructing sensing‐memory‐processing units. Here, the non‐volatile and gate‐controlled multistate photovoltaic response of a WSe2/h‐BN/graphene SFG‐FET is investigated both in experimental and theoretical aspects. Due to the ambipolar carrier transport of WSe2 channel, both electrons and holes can be stored in the graphene floating gate layer, which results in two evident memory windows on the round sweep transfer characteristic curve. Different charge‐stored states of the SFG layer enable the channel to form a lateral junction that can be adjusted by the gate voltage, which leads to the gate‐controlled multistate photovoltaic response. A theoretical model is implemented to explain the memory and the multistate photovoltaic response behaviors in a quasi‐quantitative level. The relationship between the charge‐stored states in the SFG and the photo‐response, as well as its dependence on the gate voltage are systematically analyzed. These research results provide a reliable way for realizing high‐performance multi‐functional photodetectors based on SFG‐FETs and for thorough understanding the complicated optoelectronic behaviors of SFG‐FETs.

Neutron detection in mixed short-pulsed fields with intense photon flashes for LINAC-based active interrogation applications

High-energy photon interrogation has established itself as a valuable tool for detecting special nuclear materials and characterizing nuclear waste. Previous research predominantly uses around 9-MV linear electron accelerators (LINACs) as photon sources and limited exploration has been conducted on the use of organic scintillators to determine the energy deposited in the detector and to separate photon and neutron radiation, crucial when the photon interrogation is based on the measurement of the neutron emission. The challenge arises from the intense photon flux typically produced by electron accelerators, resulting in issues such as pulse pile-up, detector saturation, and a suboptimal signal-to-background ratio. This study aims to extend the applicability of the conventional Active Photon Interrogation (API) techniques by introducing a novel method enabling the detection, in addition to nuclear materials, of light elements—specifically nitrogen, oxygen, and carbon—known to be present in conventional explosives, narcotics, and chemical weapons. The approach relies on active photon interrogation at high energies above 12 MeV, coupled with photoneutron spectrometry. Using a 22-MV electron LINAC, pulse shape discrimination with an organic liquid scintillator demonstrated promising performance. Our results highlight that the conventional pulse shape discrimination capabilities and rapid time-scale operation of organic scintillators enable the detection of fast neutrons from (γ,Xn) reactions, even in a mixed short-pulsed field of photon and neutron radiation with intense photon flashes. This exploration of the initial experimental aspects of photoneutron detection induced by high-energy photons establishes a foundation for a promising new method for the detection of illicit materials.

Adapting the DIST-M Model for Designing Experimental Activities—A Theoretical Discussion from an Interdisciplinary Perspective

This study focuses on interdisciplinary approaches within mathematics and physics education. Secondary schools, particularly those specialized in scientific curricula, have opportunities to explore common topics between mathematics and physics; however, creating a coherent interdisciplinary educational experience is challenging. Adopting an interdisciplinary perspective when designing learning sequences becomes imperative. The proposed approach harnesses the power of storytelling to engage students, emphasizing the interconnectedness of subjects and humanizing the evolution of scientific ideas. This study investigates the adaptation of the Digital Interactive Storytelling in Mathematics (DIST-M) model for interdisciplinary storytelling learning sequences. It aims to explore how this model, initially developed for mathematics activities in a virtual environment, can be enriched with elements from inquiry-based learning models to integrate the experimental aspects of physics. The research presents a theoretical discussion grounded in the design of a learning sequence centered around the study of light, taking place in a non-virtual environment and approached from an interdisciplinary standpoint. It introduces hypotheses for adapting the DIST-M model to accommodate interdisciplinary storytelling sequences. One involves the incorporation of an additional phase within the DIST-M cycle, dedicated to consolidating, transferring to other contexts, and addressing variations in the concepts explored, proved, and refined in earlier phases.

Deciphering global patterns of forest canopy rainfall interception (FCRI): A synthesis of geographical, forest species, and methodological influences

Forest canopy rainfall interception (FRCI) is an essential hydrological process that governs water and biogeochemical cycles in forest ecosystems. Identifying patterns and relationships of FCRI using a systematic review is key to improving our knowledge supporting new experiment research, modeling, and application. In this meta-analysis, we aimed to delineate the canopy interception (CI), throughfall (TF), and stemflow (SF) concerning geographical and forest variables and experimental methodologies. We leveraged peer-reviewed 170 articles across 234 sites globally, extracting TF, CI, SF, geographical, forest, and experimental aspects. We applied multivariate statistical procedures to discern the principal influences on TF, CI, and SF and examined their multicollinearity. In addition, we developed Generalized Linear Models (GLM) for CI and TF. Global TF experiments indicate that the predominant rainfall devices, number of sample trees, number of events, and monitoring length are 10–20 devices (81% fixed), 3–6 trees, 30–50 events, and 10–30 months. Predominant global values of TF, CI, and SF are 70–80% (median = 73%), 20%–30% (median = 23.9%), and <1.0% (median = 1.87%), respectively. Global models of CI and TF were responsive to T, LAI, and D (respectively, R2adj of 0.196** and 0.206**). Temperate forests mirrored the global model (R2adj of 0.274** and 0.31**, respectively). The Subtropical CI model was fitted based on P and DBH (R2adj = 0.245*), and the TF model was based on E, D, and LAI (R2adj = 0.532**); the Mediterranean CI model was based on T, Basal, and LAI (R2adj = 0.45*), while TF was based on P, Basal, and LAI (R2adj = 0.671**). The Tropical CI model was based on T and H (R2adj = 0.396*), and the TF model, LAI, and P (R2adj = 0.35*). This meta-analysis underscores the importance of comprehending the hydrological processes in forested areas as they are pivotal in mitigating climate change impacts.

A hierarchically normalized physics-informed neural network for solving differential equations: Application for solid mechanics problems

Physics-informed neural networks (PINNs) usually confront significant difficulties to accurately solve partial differential equations (PDEs) due to many pathologies caused by gradient failures during training process. In this paper, a gradient disease regarding the ill-conditioned loss function of the PINN methodology is intensively investigated in both theoretical and experimental aspects. Particularly, the regular PINN approaches can obtain good predictions for trivial problems but may fail to learn solutions when their PDE coefficients and/or physical domain sizes vary. Besides, the influences of neural network structure to the PINN training quality are inferred from the theoretical analyses and also confirmed by relating experiments, in which using large-width multi-layer perceptrons (MLPs) is proved to be beneficial in stabilizing PINN training process. To overcome the abovementioned restrictions, a novel PINN methodology using hierarchically normalized technique (hnPINN) motivated from the developed theory is devised. The key idea of the proposed hnPINN is, on the one hand, to transform the original PDE system into one of two proposed dimensionless forms to alleviate the negative effects of PDE coefficients and domain size; on the other hand, to use secondary output scalers to flexibly calibrate the gradient flow for training effectively and improving the solution preciseness. The determination of the secondary output scaler is formulated by a heuristic framework inspired from theoretical analyses on the hnPINN gradient flow. The obtained results from some typical PDEs and common problems in solid mechanics strongly confirm the high effectiveness of the hnPINN in terms of solution accuracy, superior convergence and performance stability in comparison to those of the vanilla PINN and the non-dimensionalized PINN (ndPINN). As a preprocessing procedure, the hnPINN method is independent on network architectures and also greatly potential to combine with other state-of-the-art PINN models for effectively solving challenged issues in practice.

Enhancing Biometric Attendance Systems for Educational Institutions

his research paper aims to contribute to the field of biometric attendance systems by conducting a comprehensive analysis of fingerprint-based attendance systems described in the provided abstracts. The focus will be on systems designed for educational institutions with an emphasis on time efficiency, user satisfaction, and accuracy in attendance tracking. The study will compare and contrast the methodologies, technologies, and implementation details presented in the abstracts, identifying strengths and weaknesses of each system. Special attention will be given to the use of Internet of Things (IoT) technology, biometric design processes, and the integration of fingerprint sensors with microcontrollers like ESP32.Furthermore, the research will explore optimization strategies to enhance the overall performance of these systems. This includes investigating the feasibility of incorporating advanced fingerprint identification algorithms, improving user interface design, and streamlining the data collection and storage processes. The experimental aspect of the research will involve implementing the proposed optimization strategies on a prototype system and evaluating its performance against the existing systems. Metrics such as fingerprint identification accuracy, average matching time, and system efficiency will be measured and compared to demonstrate the effectiveness of the proposed enhancements.

Equilibrium reconstruction constrained by the consistency of current simulation on EAST

The attainment of a reliable equilibrium is a critical aspect of tokamak experiments and physics analysis. A common method for establishing a reliable equilibrium current involves reconstructing it from indirect measurements, such as those obtained from polarimeter-interferometers (POINT) and motional Stark effect (MSE) systems. However, uncertainties still exist in the reconstruction results. For the equilibrium reconstruction on the EAST tokamak, which is based on the POINT system, the primary sources of uncertainty are the limited scope of measurements and the sensitivity of the reconstruction process. This paper proposes an enhanced approach that utilizes current simulation as a constraint to maintain consistency between the initial equilibrium and the simulated results. The radio frequency waves driven current is identified as a particularly influential component due to its interaction with the q profiles of the equilibrium and the deposition region of the waves. Two specific discharges are presented to illustrate how a new equilibrium can be achieved, which enhances consistency between the equilibrium and the simulated current, taking into account the dependencies of various components.

Unravelling the mechanisms of CE-SSFP in imaging myocardium at risk: The effect of relaxation times on myocardial contrast

PurposeThe aim of this study was to investigate the contrast mechanisms of Contrast-enhanced steady-state free-precession (CE-SSFP) through the utilization of Bloch simulations in an experimental porcine model and in patients with acute myocardial infarction. MethodsSix pigs and ten patients with myocardial infarction underwent CMR and tissue characterization at 1.5 T whereas a Bloch simulation framework was utilized to simulate the CE-SSFP signal formation and compare it against the actual CE-SSFP signal acquired from the experimental porcine model and the patient population. The relaxation times of remote, salvaged, and infarcted myocardium were calculated after the injection of gadolinium, at the time of CE-SSFP acquisition. Simulations were performed using the same CE-SSFP pulse sequence as used on the scanner on a set of spins with the calculated relaxation times from the CMR scans. ResultsThe normalized signal intensities of salvaged and infarcted myocardium obtained with simulations were lower than the corresponding normalized signal intensities obtained in vivo in pigs (p < 0.05, 134% vs 153%) and in patients (p < 0.05, 126% vs 145%). The results from simulations showed a linear relationship to the results obtained in the experimental porcine model (r2 = 0.61) and in patients (r2 = 0.69). ConclusionThe T1 and T2 values of remote, salvaged, and infarcted myocardium only partly explain the signal intensities in CE-SSFP images. Bloch simulations suggest that there may be more elements that contribute to the CE-SSFP contrast. Integration of other aspects of the MR experiment into the simulation model could further help to fully unravel the mechanisms of CE-SSFP.

Synthesis, structure and effects of an azoimine functionalized iridium complex on cancer cells

A novel ligand L having azoimine bond with quinoline moiety reacts with [(2-ppy)2Ir(μ-Cl)]2 in dichloromethane medium to produce an iridium(III) complex of composition [Ir(2-ppy)2(L)]. Here, the iridium centre is bound to neutral bidentate N, N donating sites of the ligand (L), where the azo part of L is not involved in chelation. The ligand and complex are characterized by elemental analysis, NMR spectroscopy, ESI-MS mass spectrometry, FTIR, UV–Vis and luminescence spectroscopic techniques. The ligand structure and the geometry around iridium centre of complex [Ir(2-ppy)2(L)] is confirmed by the single-crystal X-ray diffraction (XRD) method. DFT studies were also performed to support the experimental aspects of the complex as well as electronic distribution in molecular orbitals of various energy states. The complex exhibits blue emission band at 428 nm with quantum yield (Φ) 0.136. Further, in vitro analysis of the anticancer activity of the complex was studied mainly with the MCF - 7 cell line. The results showed that the complex have good IC50 values when compared to the standard drug cisplatin.

Modeling and Experiment of the Vibro-Acoustic Response of Cylindrical Shells With Internal Substructures

Abstract This study investigates the theoretical and experimental aspects of the vibro-acoustic characteristics of cylindrical shells with internal substructures. On the theoretical side, a hybrid calculation method is proposed, which combines the condensed transfer function method with the direct stiffness method and the precise transfer matrix method. The cylindrical shell with internal substructures is decoupled, and the governing equations for the cylindrical shell substructure and the internal substructure are separately established. Furthermore, the coupling forces between the cylindrical shell substructure and the plate substructure are solved based on the condensed transfer function method. These coupling forces are then incorporated into the overall transfer equation of the cylindrical shell to obtain the vibro-acoustic response of the coupled structure. Compared with the finite element calculation results, the validity of the calculation method in this paper is verified. In terms of experiments, the natural frequency, mode, and vibration acoustic response of the model were tested and compared with the theoretical results, which was in good agreement. The study demonstrates that the proposed hybrid calculation method based on the condensed transfer function is effective in predicting the vibro-acoustic characteristics of cylindrical shells with internal substructures.

Sinemada Mekân Kurgusunun İnsan Ölçeği Üzerinden Analizi: ‘The Secret World of Arrietty (Arietti’nin Gizli Dünyası)’

Space design is a research field with a broad framework that interacts with different disciplines. Scale, one of the most important components of this field, is used to increase the cinematic effect in the configuration of film spaces. While literature has several studies on cinema and space, little research has been conducted on animation and human size. Because of the use of two distinct human scales and the association of houses with these, this work differs from similar researches. This study aims to reveal the impact of the human scale on the production of the spatial configuration by using the experimental aspect of the cinema. The objective is to evaluate data that effectively informs the audience about scale differences. In this study, the qualitative research method was used through descriptive analysis. The study was conducted by coding, analyzing, and following the findings through scenes in the example of the film The Secret World of Arrietty. As a result of coding, five main themes were obtained. The themes with the highest frequency value were human scale and space. In the conclusion we state that the use of the combination of codes in cinema and perception changes with the change in human size allowing audiences to transfer the meaning.

Post-COVID-19 approach to teaching an undergraduate laboratory class focused on experimental design and data interpretation.

To best prepare students for the real-world research environment, key skills, including experimental design, data analysis, communication of results, and critical thinking, should be key components of undergraduate science courses. Furthermore, the impact of the COVID-19 pandemic on in-person teaching has resulted in a need to develop courses that enable flexible learning. This paper details the laboratory component of a senior-level toxicology class that was developed to emphasize all these skills and allow for flexible learning. The aim of the laboratory class was for students to determine how curcumin protected against acetaminophen-induced hepatoxicity. To stimulate critical thinking, students were required to choose a maximum of four experiments from the six on offer. Before conducting an experiment, students stated a hypothesis and selected the appropriate treatment groups. Once an experiment was completed, students were given access to a complete dataset, on which they performed statistical analysis and drew conclusions. Students who were unable to attend the laboratory session in person were able to complete the required pre-lab work and access the dataset. Following each experiment, students could write a lab summary, and receive thorough feedback. The final assessment was a written manuscript of their findings as well as a chance to respond to reviewer comments. This teaching approach prioritized the critical thinking, analysis, and experimental design aspects of scientific research. Overall, this structure was well received by students and it could easily be adapted for use on other life science courses.

Analysis and Evaluation of Seed-Filling Performance of a Pneumatic Interference Precision Seeder for Small Cabbages

To address the current problems of poor seed-filling performance and seed leakage of the pneumatic seed filler for cabbage, we designed a pneumatic disturbing precision seed filler for cabbage based on the auxiliary disturbing seed-filling method. This seeder can completely perturb the seed population entering the bottom of the seed box casing during the seed-filling process, thereby increasing the initial velocity of the cabbage seeds, and facilitating the smooth progress of the seed-filling process. Firstly, we carried out a theoretical analysis based on the particle dynamics of the seed-filling process of the seeder and obtained the influencing factors affecting the seed-filling performance of the seeder. Secondly, through EDEM discrete element simulation, the average speed of the seed population, the disturbance frequency, and the degree of disturbance were used as the indicators to select the seed discharge disk structure with the best seed-filling performance. In the experimental aspect, a four-factor three-level orthogonal standardized test was conducted to evaluate the seed filling performance of the planter, using the seed suction qualification rate and the seed leakage rate as the evaluation indexes. The optimal structure of the seed discharge tray was selected through polarity analysis and ANOVA. The optimal combination of parameters for the seed-filling process of the planter was obtained; linear serrated disk, 40 rpm disk rotation speed, −2500 Pa negative fan pressure, and 1.2 mm aperture diameter. After comparative validation tests, the seed suction qualification rate of the seed absorber was 95.32%, and the leakage rate was 3.11%, which was in line with the agronomic planting of Chinese cabbage seeds.

Experimental and theoretical aspects of the growth of vertically aligned CNTs by CCVD on AZO substrate

An efficient and reproducible growth of vertically aligned carbon nanotubes by CCVD requires accurate and specific setting of the synthesis parameters and the properties of catalyst thin layers. In this work, the growth of vertically aligned carbon nanotubes onto AZO (= aluminum doped zinc oxide) glass substrate covered by Al2O3 and Fe-Co catalyst layer system is presented. Investigation of the effect of catalyst composition and synthesis temperature on CVD growth revealed the optimum condition of the synthesis. The analysis of as-prepared samples by SEM, TEM and Raman spectroscopy was carried out to prove the structure and quality of carbon deposit. Theoretical considerations have supported speculative ideas about the role of the support layer, the transformation of the catalyst layer in the presence of hydrogen gas and the growth mechanism of carbon nanotubes. The mechanism of CNT growth is modelled and the order of magnitude of experimentally observed vertical linear growth rate of CNT (several nm/s) is reproduced.

Electromechanical Deformations and Bifurcations in Soft Dielectrics: A Review.

Dielectric elastomers have attracted considerable attention both from academia and industry alike over the last two decades due to their superior mechanical properties. In parallel, research on the mechanical properties of dielectrics has been steadily advancing, including the theoretical, experimental, and numerical aspects. It has been recognized that the electromechanical coupling property of dielectric materials can be utilized to drive deformations in functional devices in a more controllable and intelligent manner. This paper reviews recent advances in the theory of dielectrics, with specific attention focused on the theory proposed by Dorfmann and Ogden. Additionally, we provide examples illustrating the application of this theory to analyze the electromechanical deformations and the associated bifurcations in soft dielectrics. We compared the bifurcations in elastic and dielectric materials and found that only compressive bifurcation modes exist in elastic structures, whereas both compressive and tensile modes coexist in dielectric structures. We summarize two proposed ways to suppress and prevent the tensile bifurcations in dielectric materials. We hope that this literature survey will foster further advancements in the field of the electroelastic theory of soft dielectrics.

Magneto-optical fiber-based orbital angular momentum mode converters.

Orbital angular momentum (OAM) mode division multiplexing (MDM) systems can support large-capacity and high-speed rate information transmission, in which the OAM mode conversion devices play an important role. In this paper, the mode conversion principle of magneto-optical fiber-based long-period grating (MOF-LPG) is analyzed for further developing new magneto-optical (MO) OAM mode converters, including three types of C P 01 to O A M ±1,1, O A M ±1,1 to O A M ±2,1, and O A M ±1,1 to C P 02. It is shown that the magnetic tunability of the mode converters through the propagation constants of the eigenmodes is useful for compensating for process errors and increasing the operating wavelength range. The implementation of MOF-LPGs is also discussed from the aspect of the prospective experiments.

Journal of Experimental and Theoretical Analyses: The Journey from Research to Solutions

Six months ago (September 2023), we began the journey of publishing a new and unique Open Access journal dedicated to publishing papers on the methods and applications of analysis science in both experimental and theoretical aspects in the more relevant fields of engineering, with a focus on its hottest specialized areas [...]