Experimental Analysis Research Articles

Design and evaluation of crowdsourcing platforms based on users’ confidence judgments

Crowdsourcing deals with solving problems by assigning them to a large number of non-experts called crowd using their spare time. In these systems, the final answer to the question is determined by summing up the votes obtained from the community. The popularity of these systems has increased by facilitating access for community members through mobile phones and the Internet. One of the issues raised in crowdsourcing is how to choose people and how to collect answers. Usually, users are separated based on their performance in a pre-test. Designing the pre-test for performance calculation is challenging; The pre-test questions should be selected to assess characteristics in individuals that are relevant to the main questions. One of the ways to increase the accuracy of crowdsourcing systems is by considering individuals’ cognitive characteristics and decision-making models to form a crowd and improve the estimation of their answer accuracy to questions. People can estimate the correctness of their responses while making a decision. The accuracy of this estimate is determined by a quantity called metacognition ability. Metacoginition is referred to the case where the confidence level is considered along with the answer to increase the accuracy of the solution. In this paper, by both mathematical and experimental analysis, we would answer the following question: Is it possible to improve the performance of a crowdsourcing system by understanding individuals’ metacognition and recording and utilizing users’ confidence in their answers?

Chirality of CsPbBr3 Nanocrystals with Varying Dimensions in the Presence of Chiral Molecules.

Chiral lead halide perovskite (LHP) nanocrystals (NCs) have been attracting considerable interest for circularly polarized luminescence (CPL)-based optoelectronic applications. This study combined experimental and computational analyses to investigate how the dimensionality of 3D (cubic) to 0D (quantum dots) influences the tunable chiral emission of CsPbBr3 LHP NCs. The circular dichroism (CD) spectra have a significant blue shift from 508 to 406 nm. The dissymmetry factors for CD (gCD) change from ±2.5 × 10-3 to ±7.5 × 10-3 as dimensionality varies from 3D to 0D in the presence of the chiral molecule (cyclohexylethylamine, CHEA). A significant luminescence dissymmetry factor (glum) of ±5.6 × 10-4 is observed in the 0D CsPbBr3 NCs. Theoretical calculations using structural distortion parameters, the extent of charge transfer, and electrostatic potential profiles have revealed that the most significant enhancement of the chirality transfer occurs from the CHEA molecules to 0D NCs, and the order of chirality transfer from CHEA to CsPbBr3 NCs is 0D (quantum dots) > 2D (nanoplatelet) > 3D (cubic).

Experimental and theoretical analysis of flexural performance for EPCFA-CSP novel composite structure

The article proposes a novel composite structure, namely the Elastic Polyurethane Coal Fly Ash Corrugated Steel Plate (EPCFA-CSP). One specimen consisting solely of corrugated steel plate and seven composite structure specimens were designed to investigate the bending behavior of the EPCFA-CSP composite structure through four-point bending tests. The results indicate that incorporating mushroom-shaped steel pin shear keys into the combination of EPCFA and CSP yields the most favorable effect. With an increase in structural layer thickness from 30 mm to 50 mm, when the mushroom-shaped steel pin shear key contributes to the stress distribution within the composite structure, both bending stiffness and ultimate load of the composite structure specimen increases by 150.35 % and 63.93 %, respectively. Specimen EPCFA-(50)-CSP-II achieves a flexural stiffness of 89.40 kN/mm, a cracking load of 187.7 kN, and an ultimate load of 205.4 kN. Finally, based on experimental results, a deflection correction formula considering the reduction factor due to combination effects was derived to correct deflections at characteristic points accurately. This formula is applicable at approximately 0.6 times the ultimate load, and calculations using this formula yield ratios between calculated deflections and experimental deflections ranging from 0.88 to 0.97. This demonstrates its effectiveness in correcting deflections and provides valuable insights for designing related composite structures.

An experimental and numerical analysis of slit plate as replaceable fuse in moment resisting frame

This study contributes to the ongoing progress in developing cost-effective structural fuse solutions for steel structures, emphasizing enhanced strength, ductility, and energy dissipation capacity. These fuses are strategically placed to coincide with plastic hinge locations under lateral load. During minor seismic events, they provide substantial rotational stiffness, while during medium to large earthquakes, they leverage their post-yield strength for effective energy dissipation. Three varieties of beam-column sub-assemblages viz. single oval slit damper fuse (SOSDF), dual oval slit damper fuse (DOSDF) and single elliptical slit damper fuse (SESDF), featuring advanced replaceable fuses were evaluated using both experimental and numerical analyses under quasi-static loading conditions. The seismic performance of these specimens was comprehensively assessed, focusing on characteristics such as moment-carrying capacity concerning rotation, energy dissipation, ductility, and failure modes. The findings indicate that all specimens exhibited stable hysteresis, with connections utilizing SESDF and DOSDF showing slightly higher moment carrying capacities (19 % and 10 %, respectively) compared to those employing SOSDF. According to AISC 2016 standards, all three connections were classified as full-strength connections. Moreover, the ductility of specimens incorporating SESDF was notably higher as 3.5, marking a 28 % and 26 % increase over the ductility of SOSDF and DOSDF connections, respectively. In major seismic events, damage was confined solely to the fuse components, with no damage observed in the beam and column. Detailed finite element analysis using ABAQUS CAE further corroborated these findings, demonstrating good alignment between experimental and simulated results.

Variation of the acoustic response of Karadeniz kemenche due to the size and geometry of the sound holes

This study deals with the changes in acoustic response caused by variations in the geometry and size of the sound holes in the Karadeniz kemenche, a bowed string musical instrument. Starting from a 3D scan of the instrument, a finite element model is built. The structural model is verified with the results of an experimental modal analysis study, followed by a model update procedure implemented by frequency optimization. The acoustic cavity is simplified to a rectangular geometry to analytically verify the acoustic cavity modes. Before analysing the variation of the sound holes, a verification of the structure-borne noise of the musical instrument is performed. The variation of acoustic response depending on the size and geometry of the sound holes are studied using the verified vibroacoustic model. The various geometries are inspired by shapes chosen for both ancestral and contemporary bowed string instruments. The normalized loudness levels attributed to each variation are computed and examined to see if a relationship could be found to evaluate the variations.

Experimental and numerical study on dynamic response of a photovoltaic support structural platform with a U-shaped tuned liquid column damper

A tuned liquid column damper (TLCD) is widely used in offshore structures as a passive energy dissipation device to reduce the harm of wind, wave, and current loads to the safety of offshore platforms. This investigation explores the dynamic response and interaction mechanism of a photovoltaic support structural platform (SSP) equipped with a TLCD by experimental and numerical analysis. The vibration mitigation performance of the TLCD under varying liquid depth ratios, external excitation frequencies, and amplitudes is systematically evaluated. The experiments focus on assessing the structural dynamic response and wall pressure to determine the vibration reduction efficiency of the TLCD for structures with fundamental frequencies more than 2 Hz. The experimental results indicate that the TLCD can reduce the structural response maximally near the natural frequency (2.52 Hz) of the structure, with vibration reduction effectiveness ranging from 42.0% to 85.1%. Additionally, one develops a two-way fluid-structure interaction (FSI) model to investigate further the impact of hydrodynamic pressure caused by sloshing inside the TLCD on the SSP motion response, which providing a more detailed explanation for the different phenomena observed in the experimental results.

Graphdiyne-Induced CoN/CoS2 Heterojunction: Boosting Efficiency for Bifunctional Oxygen Electrochemistry in Zinc-Air Batteries.

The performance of zinc-air battery is constrained by the sluggish rate of oxygen electrode reaction, particularly under high current discharge conditions where the kinetic process of the oxygen reduction reaction (ORR) decelerates significantly. To address this challenge, we present a novel phase transition strategy that facilitates the creation of a heteroatom-doped heterointerface (CoN/CoS2). The meticulously engineered CoN/CoS2/NC electrocatalyst displays a superior ORR half-wave potential of 0.87 V and an OER overpotential of 320 mV at 10 mA cm-2. Experimental and computational analysis confirm that the CoN/CoS2 heterostructure optimizes local charge distribution, accelerates electron transfer, and tunes active sites for enhanced catalysis. Notably, this heterojunction improves stability by resisting corrosion and degradation under harsh alkaline conditions, thus demonstrating superior performance and longevity in a custom-made liquid zinc-air battery. This research provides valuable practical and theoretical foundations for designing efficient heterointerfaces in electrocatalysis applications.

Multi-objective optimization, shrinkage and fracture properties of unsaturated polyester resin modified concrete for bridge deck pavement based on system theory

For the purpose of fabricating unsaturated polyester modified concrete (UPMC) with excellent shrinkage and fracture properties for bridge deck pavement, the optimization design of mix proportion and enhancement mechanism analysis were implemented based on system theory. Firstly, for unsaturated polyester resin (UPR) subsystem, the viscosity, mechanical properties and droplet-size distribution were analyzed to determine the types and dosage of auxiliary additives after emulsification treatment; Next, for UPMC mortar slave-system, the optimization design was implemented through the combination of experimental analysis and hybrid multi-attribute ellipsoidal decision of grey-target (HMEDG) model; Subsequently, for UPMC main-system, the optimal proportion was determined utilizing orthogonal design test. Finally, the variation law and enhancement mechanism on fracture properties and shrinkage characteristics of UPMC was analyzed by combining macroscopic test, thermogravimetry (TG) and X-ray diffraction (XRD). The results demonstrated that 2.0 wt%BPO+1.0 wt%DMA and meta-benzene types UPR were utilized as auxiliary additives for UPMC based on the results of HMEDG models. The demulsified and cured WUP might supplement the interior moisture losses based on humidity compensation, and substantially constrain the evaporation loss inside the matrix, upgrading the hydration degree and facilitating the generation of hydration products. The introduction of 3 %-6 % waterborne-UPR (WUP) would improve 28d-fracture toughness within approximately 23.33 %-49.32 %, and reduce the shrinkage deformation by roughly 28–43 % through inducing the crack tip stress redistribution against the initiation and propagation of interior microcracks and enhancing the homogenization and densification.

An Investigation of Tensile, Fatigue, and Fracture Behavior of 3D-Printed Polymers

Abstract The progression of manufacturing technology has significantly benefited from the adoption of 3D printing techniques, which enable the production of parts with intricate geometries. However, it is important to acknowledge that components fabricated through this additive manufacturing method frequently manifest defects and are prone to failure under severe conditions. Therefore, a thorough examination of the mechanical properties of these parts is essential to effectively reduce the failure. This study aimed to explore the mechanical properties of two prevalently used 3D-printed polymers, specifically Onyx and acrylonitrile butadiene styrene (ABS), by integrating computational and experimental analyses. The experimental study utilized a material testing system and digital image correlation (DIC) technology, while the computational analysis covered the finite element (FE) modeling of the 3D-printed samples. The research focused on evaluating the tensile strength and fatigue resistance of the specimens printed in various orientations, alongside a detailed investigation of their fracture behavior. The crack propagation analysis was carried out using the DIC system and the separating morphing and adaptive re-meshing technology (SMART) scheme in ansys. It was observed that upright build orientation produced the weakest samples for axial loading and specimens with notches failed earlier than those without. Moreover, Onyx was found to have a higher resistance to fracture or failure compared to ABS. The FE modeling results demonstrated strong agreement with the experimental results, validating their accuracy and reliability in characterizing the critical mechanical response of 3D-printed parts rapidly and cost effectively.

Experimental design, mechanical performance and mechanism analysis of C30 phosphogypsum-based concrete

The present study aimed to increase the utilization of phosphogypsum and reduce cement consumption. Single-factor experiments were designed to the effects of water-cement ratio (0.45–0.30), silica fume (1 %∼7 %), cement dosage (0 %∼20 %), and the RPG/HPG (20/80–0/100) on mechanical properties of phosphogypsum-based concretes (PGBCs). A new phosphogypsum-based concrete was prepared to meet the compressive strength requirement of C30 grade. The maximum 28d compressive strength of this PGBC reached 45.1 MPa. Simultaneously, the effect mechanisms of above four factors on the mechanical properties of PGBCs were discussed by combining XRD and SEM results. Moreover, the volume stability, elastic parameters, and compressive constitutive model of this PGBC with compressive strength above 30 MPa were investigated. This PGBC used more than 80 % phosphogypsum and 10∼20 % cement, exhibiting well economy and environmental friendliness. Moreover, the constitutive model was established to well predict the compressive behavior of PGBC with different RPG/HPG relative ratios. This PGBC had better volume stability and weaker deformation resistance than cement-based concrete. The present results can provide more theoretical and technical supports for the large utilization of PG.

Experimental, theoretical and optimization studies on multimode vibration reduction of floating raft system based on NES cells

Most of the studies on multimode vibration reduction of floating raft systems remain at the stage of theoretical analysis, while relevant experimental studies are rare. In this paper, an experimental setup for a scaled-down floating raft system is constructed. The vertical track nonlinear energy sink (TNES) cells are experimentally applied for the first time to suppress the multimode vibration of the floating raft system. To ensure the damping effect is not affected by additional mass, the TNES cells are always installed on the floating raft system. The TNES is able to achieve vibration suppression by allowing unrestricted movement of its vibrator. Two damping systems with different TNESs placement are proposed. Experimental modal analysis is performed on the floating raft structure to determine its response characteristics. Based on the results, different magnitudes of excitation force are applied to each order mode to effectively suppress the multimode vibration of the system. Meanwhile, the nonlinear system coupled with TNES cells is analyzed using the harmonic balance method (HBM) to obtain the approximate analytical solution. The system responses obtained from the analytical solution are compared with the experimental data results. The particle swarm optimization (PSO) algorithm is used to obtain the optimal parameters of the TNESs for vibration suppression. The results show that the multimodal vibration of the floating raft structure is effectively suppressed by the TNES cells in both experimental and theoretical analyses. The vibration suppression effect for all modes is significantly improved by the PSO algorithm. In conclusion, the research content of this paper provides a practical and feasible vibration suppression solution for the design of floating raft systems.

Experimental Analysis of Bonding in Steel Glued into Pine Timber

Combining steel with wood has been practised for many years. The issue is related to two main areas, i.e., bonding steel elements with wood so that they serve as connectors facilitating the assembly of wood elements and bonding steel elements to wood beams to improve their load-bearing capacity. In the first case, the adhesives used may be relatively expensive and more difficult to apply, whereas in the second one, especially when steel elements are glued inside the glulam (GL) beams, it is better if the adhesives used are more accessible to apply and cheaper. As it seems rational to reinforce wood with high-modulus ties, research has been carried out to compare the connection quality of commercially available adhesives that can be used for this purpose. Moreover, thermosetting adhesives have been applied as an alternative and cheaper solution. Thermostat adhesives also have a high pH of the bond, which prevents the steel from rusting. The research shows that the load-bearing capacity of the bond depends on whether the bars are ribbed or sheet metal. Moreover, among thermosetting adhesives, the most favourable load-bearing values were obtained using a mixture of PF/pMDI (phenol formaldehyde resin/polymeric diphenylmethane diisocyanate) and powder from recycled tyres. The shear strength of these joints was 1.63 N/mm2 and 3.14 N/mm2 for flat specimens and specimens with ribbed bars, respectively.

The spectral inversion model for electrical conductivity in mural plaster following phosphate erosion based on fractional order differentiation and novel spectral indices

The Dunhuang murals are a precious treasure of China’s cultural heritage, yet they have long been affected by salt damage. Traditional methods for detecting salt content are costly, inefficient, and may cause physical harm to the murals. Among current techniques for measuring salt content in murals, hyperspectral remote sensing technology offers a non-invasive, circumventing issues of high costs, low efficiency. Building on this, the study constructs an inversion model for the Electrical Conductivity (EC) values of mural plaster subjected to phosphate erosion, through the integration of Fractional Order Differentiation (FOD), a novel three-band spectral index, and the Partial Least Squares Regression algorithm. The specific research contents include: (1) Initially, in preparation for the experiments, the materials used to create the samples underwent a rigorous desalting process, and phosphate solutions were prepared using deionized water to ensure uniform experimental conditions and the accuracy of the results. These meticulous preprocessing steps guaranteed that the measured EC values exhibited a clear correlation with the phosphate content. Subsequently, by employing qualitative experimental analysis techniques, this study was able to more accurately simulate the real-world scenarios of mural plaster affected by salt damage, enabling a deeper investigation into the mechanisms by which salts inflict microscopic damage to murals. (2) Explores the absorption mechanisms and characteristic spectral bands of the Electrical Conductivity (EC) values measured after the phosphate erosion of mural plaster. By integrating the optimal spectral indices, a univariate linear regression model is constructed, providing a basis for the rapid quantitative measurement of electrical conductivity in murals. (3) By comparing the accuracy of the Phosphate Simple Ratio (PSR) and Phosphate Normalized Difference Index (PNDI) spectral indices based on the linear regression model, the first six orders of the highest accuracy spectral index were selected as the optimal three-band spectral index combination, used as explanatory variables, with mural plaster electrical conductivity as the response variable, employing the PLSR method to construct the mural phosphate content high-spectral feature inversion model. The study’s findings include: (1) Surfaces of samples deteriorated by phosphate erosion formed numerous irregularly shaped crystal clusters, exhibiting uneven characteristics. (2) By comparing the outcomes of different orders of fractional differentiation, it was found that the model performance reached its optimum at a 0.3 order of differentiation for both PSR and PNDI data, with a determination coefficient (Q2) of 0.728. (3) Utilizing PLSR, this study employed the previously determined optimal six-order three-band spectral index combination as explanatory variables, with salt content as the response variable, successfully constructing the high-spectral feature inversion model for mural electrical conductivity with a determination coefficient (Q2) of 0.815. This provides an effective technical means for monitoring the salt damage conditions of precious cultural heritage such as murals.

Nonlinear optical response and application of indirect narrow-bandgap SbTe nanosheets

The nonlinear optical properties of antimony telluride (SbTe) crystal with indirect narrow bandgap are investigated, which exhibits superior performance for nonlinear laser modulation in the infrared band. The nonlinear optical coefficients of SbTe nanosheets are determined to be −3.3 cm/GW, −2.3 cm/GW, −1.9 cm/GW and the modulation depths are 5.5 %, 2.0 %, 1.5 % at 400 nm, 800 nm, 1064 nm, respectively. Based on the SbTe-SA, a Yb:GdScO3 laser centered at 1064 nm is achieved with 633 mW maximum output power, 56 fs pulse width and 104 MHz repetition rate. The damage threshold of the SbTe nanosheets is calculated to be exceed 338 GW/cm2, revealing the great potential in high-power laser modulation. This investigation marks the inaugural theoretical and experimental analysis of SbTe’s optical properties and its application in laser modulation, laying the groundwork for future research into indirect narrow-bandgap materials in laser technology.

The Analytical and Experimental Analysis of the Machined Surface Roughness in High-Feed Tangential Turning

A main topic in mass production of machine parts is how to increase the productivity to produce more parts in a given time while maintaining the prescribed surface quality on the machined surfaces. Novel machining procedures have been introduced to achieve this goal; however, the further development of already established and wide-spread procedures can offer simply accessible solutions. Tangential turning is a rediscovered variant of the traditional turning procedure, where a specially designed cutting tool ensures chip removal with a feed tangential to the workpiece. This process results in low surface roughness even at higher feed rates. In this paper, the achievable surface roughness is analyzed by analytical and experimental steps. In the mathematical analysis, the theoretical surface roughness is determined using the constructive geometric modelling method. The worked-out equations are validated in cutting experiments on 42CrMo4 grade steel workpieces. The theoretical and experimental analyses show that the strictly prescribed surface roughness can be achieved with high feed rates by the application of tangential turning.

An Enhanced Deep Learning-Based Pharmaceutical Crystal Detection with Regional Filtering

In the process of pharmaceutical crystallization, the automatic detection of crystal shapes in images is important since controlling the morphology of the crystals improves the quality of pharmaceutical crystals. In this paper, a novel image detection method called RECDet is proposed. It leverages an automatically adapted binary image to bypass background regions, thereby reducing the detection field. In addition, the method greatly reduces the training time while improving the detection accuracy by using a specially designed detection box for the crystal shape. The performance of our model is evaluated through experimental analysis on a publicly available glutamate crystal dataset and a self-made entecavir pharmaceutical crystal dataset. Experimental results show that RECDet improves the accuracy of prediction bounding boxes by more than 2% compared to other popular models and achieves a classification accuracy of 98%. It can be used as a promising tool in the application of pharmaceutical crystallization control.

An Experimental Analysis on Performance Assessment of Green Vehicles with Integration of Green Energy

An Experimental Analysis on Performance Assessment of Green Vehicles with Integration of Green Energy

An experimental analysis and deep learning model to assess the cooling performance of green walls in humid climates

Introduction: Amidst escalating global temperatures, increasing climate change, and rapid urbanization, addressing urban heat islands and improving outdoor thermal comfort is paramount for sustainable urban development. Green walls offer a promising strategy by effectively lowering ambient air temperatures in urban environments. While previous studies have explored their impact in various climates, their effectiveness in humid climates remains underexplored.Methods: This research investigates the cooling effect of a green wall during summer in a humid climate, employing two approaches: Field Measurement-Based Analysis (SC 1: FMA) and Deep Learning Model (SC 2: DLM). In SC 1: FMA, experiments utilized data loggers at varying distances from the green wall to capture real-time conditions. SC 2: DLM utilized a deep learning model to predict the green wall’s performance over time.Results: Results indicate a significant reduction in air temperature, with a 1.5°C (6%) decrease compared to real-time conditions. Long-term analysis identified specific distances (A, B, C, and D) contributing to temperature reductions ranging from 1.5°C to 2.5°C, highlighting optimal distances for green wall efficacy.Discussion: This study contributes novel insights by determining effective distances for green wall systems to mitigate ambient temperatures, addressing a critical gap in current literature. The integration of a deep learning model enhances analytical precision and forecasts future outcomes. Despite limitations related to a single case study and limited timeframe, this research offers practical benefits in urban heat island mitigation, enhancing outdoor comfort, and fostering sustainable and climate-resilient urban environments.

Experimental and Numerical Study of Air Flow Reversal Induced by Fire in an Inclined Mine Working

Effective fire prevention in mine workings and tunnels requires a thorough theoretical analysis of the heat and mass transfer processes within these structures. This involves using established models to calculate non-isothermal air flow dynamics in long tunnels and mine workings. While the ventilation of tunnels has been extensively studied, significant challenges persist regarding mine ventilation systems, particularly due to their complex and branched topology. This study aimed to address these challenges and gaps in mine ventilation. We designed a laboratory bench to simulate an inclined mine working with a heat source (fire) and validated a mathematical model of heat and mass transfer in such settings. Using experimental measurements, we verified the model’s accuracy. It is important to note that our experimental and theoretical analyses focused solely on the thermal effects of a fire, without considering the release of harmful impurities. Using the validated model, we conducted multiparameter simulations to identify the conditions leading to the formation of a thermal slug in an inclined mine working and the subsequent reversal of air flow. The simulation data enabled us to determine the dependency of the critical heat release rate on the aerodynamic parameters of the mine working. Additionally, we evaluated the changes in average air density within a mine working at the critical heat release rate. These findings are crucial for the further development of a network-based method to analyze air flow stability in mine ventilation networks during fires.

Unraveling the mechanics of directional coarsening in single crystal Ni-based superalloys via laser peening: Insights from experimental characterization and microstructural analysis

Surface treatment techniques, like laser peening, enhance the longevity of Ni-based superalloy components by reinforcing their microstructure against surface-initiated damage. Recent findings suggest that these methods may also influence precipitate coarsening behavior at high temperatures, leading to rafting phenomena. This study extensively examined γ’ rafting in single crystal Ni-based superalloy CMSX-4 post laser peening and heat treatment. X-ray diffraction revealed surface compressive stresses (-400 MPa to -800 MPa), transitioning to tensile stresses at greater depths before returning to an unstressed state. Correlation with electron microscopy indicated horizontal coarsening in compressive regions and vertical coarsening in tensile regions due to misfit and residual stresses aiding diffusion. Plastic strain near the LPed surface was measurably increased with lattice misorientation values around 5° before returning to an unstrained state after heat treatment due to rafting-aided recovery and defect reorganization. Secondary γ’ precipitates with a radius of approximately 10 nm occupied γ channels between rafted precipitates, indicating solute element diffusion and supersaturation. Energy dispersive x-ray spectroscopy showed a significant depletion of γ’-forming elements around rafted primary precipitates, highlighting preferential solute diffusion.