Experiment Study Research Articles

Experimentation Study of Sound and Vibration Absorption in Two-Wheeler Engines using Tea Waste and Nano-Clay Material

Experimentation Study of Sound and Vibration Absorption in Two-Wheeler Engines using Tea Waste and Nano-Clay Material

Exploration of preferences among people with COPD to inform resource allocation: a discrete choice experiment study

IntroductionTreatment options for chronic obstructive pulmonary disease (COPD) are numerous but adherence remains a key challenge. We performed a discrete choice experiment (DCE) of patients’ preferences in accessing care for...

A Wind Tunnel Experiment Study on Splash Functions During Sand Saltation

AbstractSplash functions delineate the intricate interaction between wind‐driven particles and the bed. However, due to limitations in measurement methods, achieving a comprehensive understanding of splash functions remains challenging. In this study, we utilized a high‐speed system and particle trajectory tracking algorithm to reconstruct 857 collision events involving natural sand particles obtained from field samples and artificial glass microspheres interacting with a bed composed of analogous particles in a wind tunnel. During the experiments, the ratio of the wind shear velocity (u*) to the impact threshold (u*ti) consistently ranged between approximately 1.22 and 1.79. Our findings indicate that the impact angle remains independent of both impact velocity and particle size, maintaining an approximate value of 10.5 ± 6.5°. The evaluation of splash functions depends on the criterion used to define ejection, that is, the ratio of the centroid's height of the liftoff particles to their particle size (H/d). Additionally, at the same critical height (H/d = 1.5), our splash functions show differences of varying degrees from previous experiments and theoretical studies performed under no wind conditions. We believe that the main reason for these differences may be that the energy exchange between the bed surface and the airflow increases the looseness of the large‐particle (>0.1 mm) bed surface. These findings hold significant implications for accurately modeling sand‐bed collisions in natural environments.

Morphological properties of two-dimensional and three-dimensional bedforms in open channel flow: A flume experiments study

Bedforms are formed by sediment particles under the action of flow, which in turn affect flow and sediment movement. However, the fundamental mechanisms behind the formation and development of bedforms under varying flow conditions, the interconnection between sediment particle movement and bed morphology development, as well as the influence of bedforms on flow and sediment transport, are still not well understood. In the current study, the moveable bed load transport flume experiments under different flow conditions were done, and the development processes of two-dimensional and three-dimensional dunes formed under different flow intensities were simulated. The detailed structure of the bedforms was measured by laser scanning technology, the characteristics of the bedforms were analyzed in detail, and the relations between the formation of the bedforms and the movement of sediment particles are discussed. The results found that the correlation coefficients of the longitudinal profile curve can serve as a quick reference for distinguishing two-dimensional and three-dimensional dunes. When the crestline ratio is used as the criterion for two-dimensional and three-dimensional dunes, the relative amplitude of the dune crestline and the included angle with the flow direction should also be comprehensively considered. The lee side angles of dunes calculated using the triangle generalization method and local section tangent method are compared and show that the values obtained by the former method are only about half of that of the latter. It is also found that the lee side angles of dunes are related to the dune height. The superimposed dunes generally exist in the downstream area of the stoss side of the dunes. The local bed slopes on the stoss side of the dunes show reverse slopes. The superimposed dunes improve the local bed height and further increase the reverse slope degree of the stoss side. A streamwise ridge is an important form located in the upstream area of the dunes stoss side, and they are symmetrically distributed on both sides. Multiple streamwise ridges divide the stoss side of the dunes into relatively independent movement areas, restricting the movement of sediment particles to specific regions. According to the distribution characteristics of bed morphologies, the effects of dunes on sediment particle movement and flow energy consumption are analyzed.

INVESTIGATION OF DEEP LEARNING MODELS BASED ON SINGLE-LAYER SimpleRNN, LSTM AND GRU NETWORKS FOR RECOGNIZING SOUNDS OF UAV DISTANCES

In recent years, the potential risks posed by easily moving objects have highlighted the need for intelligent surveillance systems in protected areas, primarily to ensure the safety of human lives. Among the most common of these objects are unmanned aerial vehicles (UAVs). Recent advances in deep learning techniques for recognizing audio signals have made these techniques effective in identifying moving or aerial objects, especially those powered by engines. And the growing deployment of UAVs has made their rapid recognition in various suspicious or unauthorized circumstances critical. Detecting suspicious drone flights, especially in restricted areas, remains a significant research challenge. It is vital to perform the task of determining their distance in order to quickly detect drones approaching people in such protected areas. Therefore, this paper aims to study the research question of recognizing UAV audio data from different distances. That is, recognizing drone audio at different distances was experimentally studied using Simple RNN, LSTM and GRU based deep learning models. The main objective of this study is based on finding one of the capable types of recurrent network for the task of recognizing UAV audio data at different distances. During the experimental study, the recognition abilities of Single-layer Simple RNN, LSTM and GRU recurrent network types were studied from two basic directions: with recognition accuracy curves and classification reports. As a result, LSTM and GRU based models showed high recognition ability for these types of audio signals. It was noted that UAVs can reliably predict distances greater than 10 meters based on the proposed deep learning architecture.

Effect of an 8-week hot spring water exercise program on body composition, knee isokinetic muscle function, range of motion, and the Korean Western Ontario and Mcmaster Universities index in middle-age females with osteoarthritis in Republic of Korea: experiment study

Effect of an 8-week hot spring water exercise program on body composition, knee isokinetic muscle function, range of motion, and the Korean Western Ontario and Mcmaster Universities index in middle-age females with osteoarthritis in Republic of Korea: experiment study

Measurement of the Michel parameters in leptonic τ-decays at Super Tau-Charm facility

We present a new method for direct measurement of all Michel parameters in the [Formula: see text] decay related to the polarization of the daughter muon: [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], and [Formula: see text]. The method is based on the reconstruction of the muon decays-in-flight in the tracker of the [Formula: see text] collider experiments and relies on the correlation between muon spin and its daughter electron momentum. The low probability of decay-in-flight in the tracker volume is compensated by the unprecedented statistics of modern flavor factories, which ultimately leads to the possibility of achieving high accuracy. We discuss the application of the suggested method in the experiments at [Formula: see text] colliders and present a feasibility study for the future Super Charm-Tau Factory experiment. We also discuss the result of the first use of the proposed method in the Belle experiment, confirming its applicability.

Experiment and kinetics study on OH∗ chemiluminescence up to 3150 K in hydrogen combustion behind reflected shock waves

Chemiluminescence of OH∗ is commonly employed as an optical indicator for the combustion process. It is widely recognized that the generation of OH∗ in hydrogen flames is primarily governed by the reaction H + O + M=>OH∗+M. In this study, the time histories of OH∗ chemiluminescence from the A→X band around 308 nm were recorded behind reflected shock waves for stoichiometric and lean H2/O2 mixtures highly diluted in argon over the temperature range of 1130–3150 K and at the pressure of approximately 0.9 atm. Based on the time histories of OH∗ chemiluminescence, the best-fit reaction rate coefficient for the reaction H + O + M=>OH∗+M was determined as k = 3.17 × 1027exp(-121968 cal mol−1/RT) + 2.25 × 1017exp(-4246 cal mol−1/RT) cm6 mol−2 s−1 over the temperature range studied. Furthermore, by using the current rate coefficient in mechanism predictions, the predicted time histories and relative peak intensities of OH∗ chemiluminescence are in good agreement with experimental results reported in literature.

What happens after anti-Asian racism at work? A moral exclusion perspective on coworker confrontation and mechanisms.

Despite Americans' recent heightened awareness of racial inequality, anti-Asian racism at work remains underrecognized and largely unaddressed. In this research, we aim to understand why White bystander coworkers may fail to confront anti-Asian racism. Integrating the moral exclusion perspective and research on racial positions, we propose that due to perceiving Asian Americans as more foreign than other non-White coworkers, White coworkers are less likely to feel anger and engage in confrontation when witnessing anti-Asian racism at work. We first conducted a survey study (Study 1), demonstrating the external validity of the phenomenon that White coworkers are less likely to confront racism when the victim is Asian American versus Black. We then conducted two experiments (Studies 2 and 3) with a realistic, interactive design and behavioral measures of confrontation, supporting our hypothesized mechanisms (i.e., perceived target foreignness and anger). Study 3 further generalized our theory by including Hispanic/Latinx American targets as an additional comparison group and showing that the relative perceived foreignness among Asian American, Hispanic/Latinx American, and Black targets reduced White coworkers' anger and confrontation. We then conclude by discussing the theoretical and practical implications of our work. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Aerodynamic optimization design and experimental verification of a high-load axial flow compressor

The performance and stable operating range of compressors are critical to the efficient operation of various turbomachinery systems. This paper proposes a multi-level optimization strategy combining the uni-uniform direct free deformation method, Linux partitioned CPU accelerated parallel computing technology, multi-objective particle swarm optimization algorithm and downhill simplex algorithm, which improves design efficiency. Numerical results show that after optimization design, the average value of peak efficiency and stall margin increases. The flow mechanism of compressor performance improvement after optimization lies in the reduction of a low-velocity separation zone in stator hub region. Moreover, the experiment study confirms the reliability and accuracy of the optimization design method and found that flow instability triggering mode, propagation characteristics of the stall cell, and surge frequency are changed after optimization design. Setting a probability distribution threshold for autocorrelation coefficient and cross-correlation coefficients can be used to predict the arrival of the surge condition.

Energy consumption analysis and operating characteristics research on small time scale of variable refrigerant flow air conditioning systems in public buildings

In order to analyze the energy consumption and operation characteristics of the variable refrigerant flow (VRF) air-conditioning system on small time scale and put forward effective energy-saving suggestions, the VRF system operation experiments are carried out under different indoor set temperatures, different indoor unit opening quantities and different indoor set air velocities. This experiment studies the main influencing factors of energy consumption and operation of the VRF system, such as indoor temperature difference, indoor air velocity, outdoor environment temperature and so on. The results show that the rated power of indoor unit is linearly related to the energy consumption of the VRF system. The total active power changes greatly when the VRF starts and stops, and the outdoor ambient temperature changes. The indoor set air velocities have a great influence on the energy consumption and operation of the VRF system. The performance parameters increase first and then decrease with the increase of compressor frequency and load rate. When the load rate is 40 %∼60 %, the performance parameters can reach 3.2 ∼ 4.2.

Bubble characterization and bubble population on SiC material surface in subcooled boiling flow

A particularly promising candidate for widespread adopted Accident-Tolerant Fuels(ATF) is Silicon Carbide (SiC), which is deemed significantly advantageous for nuclear energy applications due to its remarkable characteristics. The understanding of bubble behavior on SiC surfaces is critical for the development of improved SiC designs. An experiment study was executed to evaluate the characteristics and population of bubbles on the surface of SiC material in subcooled boiling flow. The experimental setup maintained atmospheric pressure and featured a subcooling range of 0-12 K and a wall superheat from 0K to 30K, and a maximum coolant Reynolds number of 10400. The findings accentuated that the sensitivity of heat to fluid velocity during nucleation boiling is greater on surfaces with small porosity than on those with larger porosity. The Sauter mean diameter displays an upward trend in sync with increasing wall superheat, and the Sauter mean diameter can be represented as a dependence of the maximum and minimum bubble diameters. In terms of bubble distribution properties, it was discovered that bubble size and bubble aspect ratio conform to a lognormal distribution, while bubble orientation adheres to a normal distribution, and bubble circularity validates a Weibull distribution.

Molecular dynamics simulation and experiment study on a displacement-based electrochemical dual-signal response of interfacial kanamycin aptamer probe

A displacement-based electrochemical dual-signal kanamycin (KAN) aptamer sensing method was developed using a theory-driven approach, with methylene violet (MV) and toluidine blue (TB) as dual-signal labels. The binding poses were elucidated using molecular dynamics simulation (MDS) while simulating the kinetic evolution process of the displacement reaction. The binding system’s binding free energy (ΔG) was calculated using the g_mmpbsa algorithm. The MDS results guided the sensor fabrication process, and the sensing analytical performance was subsequently investigated. The study demonstrated the thermodynamic feasibility of the displacement reaction, with ΔG values of −3079 ± 122, −955 ± 78, and −879 ± 46 KJ·mol−1 for the three binding systems, respectively. The simulated kinetic evolution process aligned with the displacement reaction’s behavior characteristics, primarily driven by electrostatic attraction, thereby deciphering the sensor’s signaling mechanism. Under optimized conditions, the sensor exhibited a dual-signal response, a detection limit of 0.17 μM, a linear range of 1.0 μM to 2.0 mM, a response equilibrium time of ∼ 45 min., and a discriminated selectivity clarified by the MDS. The mutual support between MDS and experimental results establishes a communication bridge between simulation and experimentation, guiding the sensor fabrication direction and providing a methodological basis and new research example for aptamer-based sensor designs.

Crystallization and intermolecular hydrogen bonding in carbamazepine-polyvinyl pyrrolidone solid dispersions: An experiment and molecular simulation study on drug content variation

The choice of drug content is a critical factor as far as the solid dispersion is concerned. This investigation aims to build the relationship between the drug content, intermolecular hydrogen bonding and the crystalline of the carbamazepine-polyvinyl pyrrolidone solid dispersion. In this work, the microstructural changes of solid dispersions were investigated using experimental characterization combined with molecular simulation. Experimental investigations demonstrated that increasing the drug content enhances the intermolecular hydrogen bonding between drugs, resulting in the crystalline phase of the drug emerged in the solid dispersion. This negatively affects the solubility and stability of solid dispersions. Molecular simulations were then used to analyze the changes of intermolecular hydrogen bonding at different drug content in the system. It revealed a tenfold increase in drug-drug hydrogen bonding concentration as drug content elevated from 10% to 50%, while the drug-excipient hydrogen bonding concentration decreased by 45%. The correlation analysis proves the significant relationships among the drug content, intermolecular hydrogen bonding, and crystallinity of solid dispersion. Using polynomial fitting analysis, the quantitative relationships between the drug content and crystalline properties were investigated. This study will offer valuable insights into the impact of drug content on the performance of solid dispersion.

Experimental and Transformer-Based Study on Seismic Behavior and Plastic Hinge Length of RC Columns Reinforced with End-Fixed Ultra-High Strength Rebars

The application of machine learning (ML) in structural engineering is receiving increasing attention recently. This paper experimentally studies three self-restoring reinforced concrete (SRRC) columns reinforced with low-bond ultra-high strength rebars, to first discuss the reliability and evaluation of the SRRC columns under multiple reversed cyclic (MRC) loads induced by strong earthquakes, and to also first introduce the Transformer method into the analysis and discussion of structural tests. The tests confirmed the superior seismic behavior and high self-centering performance of the columns and presented how MRC loads affect the seismic performance of SRRC columns in terms of the lateral load-carrying capacity and energy dissipation capacity. Superior to conventional methods, a high-accuracy Transformer-based model is proposed to evaluate the plastic hinge height (PHL) of the tested SRRC columns compared with the other three algorithms (MLP, KNN, and XGBoost). Furthermore, the Shapley Additive exPlanations (SHAP) approach is adopted to explain the insight relationship between the structural parameters and PHL of the columns.

Numerical and experimental study of the effect of an innovative trailing-edge flap on the aerodynamic performance of small-scale horizontal-axis wind turbines

The impact of an innovative trailing-edge flap (blended TEF) on the aerodynamic performance of small-scale horizontal-axis wind turbines is numerically and experimentally studied. The blended TEF is characterized by both the pressure surface of the hinged TEF and the suction surface of the morphed TEF. The wind speed, rotational speed, and power coefficient of four wind turbines were measured in a wind tunnel. The results show that the wind turbines with the morphed and hinged blades were respectively the easiest and hardest to start, and respectively had the lowest and highest output axial thrust. Moreover, the wind turbines with the hinged and blended blades were found to have the lowest and highest output power, respectively. Compared with the original wind turbine, the wind turbine with the blended blade respectively resulted in additional power and thrust increases of 130.95% and 113.49% at the wind speed of 1.29 m/s.

Feasibility of Carbon Dioxide as Cushion Gas in Depleted Gas Reservoirs: An Experiment Study on CO2–CH4 Dispersion during Flow Alternation

Feasibility of Carbon Dioxide as Cushion Gas in Depleted Gas Reservoirs: An Experiment Study on CO2–CH4 Dispersion during Flow Alternation

Experimental study on the pool boiling heat transfer of R134a outside various enhanced tubes

The paper aims to experimentally study the pool boiling heat transfer properties of R134a outside various enhanced tubes under saturation temperatures ranged from 3 to 40 °C and heat fluxes of 5.5∼76.5 kW·m-2. One smooth tube and three micro-fin tubes were selected as the tested tube. Based on the experimental results, it can be found that the pool boiling heat transfer coefficient increases firstly and decreases later with increasing heat flux, but saturation temperature and water velocity have little effect on the heat transfer coefficient. Under the same experimental conditions, refrigerant thermal resistance ratio is greater than 0.5 during the heat transfer process. The micro-fin facilitates the bubble nucleation with the heat transfer enhancement ratio varying in the range of 2.08∼4.59. Moreover, the experimental values are compared with the calculated values of three existing correlations for the pool boiling heat transfer coefficient. The experimental variables, which mainly includes saturation temperature, heat flux and tube structure, have great influences on the correlation accuracy. Finally, to eliminate the influence of the experimental variable, a new correlation was proposed by introducing ratio of fin height to outer diameter of the tested tube. After the further verification, the proposed correlation can predict the heat transfer coefficient with the mean deviation of less than 10%.

Relieving effect of jiao-tune of 5-element music on negative emotions in patients with decompensated hepatitis B virus cirrhosis: A randomized and controlled experiment study.

Depression and anxiety are common in patients with decompensated hepatitis B virus (HBV) cirrhosis. This study aimed to evaluate the relieving effects of the jiao-tune of 5-element music on negative emotions in patients with decompensated HBV cirrhosis. The patients were randomly allocated into the control group (standard nursing care) and the jiao-tune group (standard nursing care plus a 2-month course of music therapy with the jiao-tune of 5-element music). The negative emotions of patients were assessed before intervention treatment and at the end of the 2-month follow-up using the Zung Self-Rating Depression Scale (SDS) and Zung Self-Rating Anxiety Scale (SAS). The analysis included 209 patients, with 102 in the control group and 107 in the jiao-tune group, all of whom returned their completed questionnaires. Baseline clinical characteristics and length of hospital stay were comparable between 2 groups. Before intervention treatment, there were no significant differences in SAS score (55.78 ± 5.64 vs 56.47 ± 3.28) and SDS score (65.13 ± 3.12 vs 64.48 ± 4.47) between the jiao-tune group and control group. After 2-month follow-up, the jiao-tune group had a significantly lower SAS score (53.17 ± 5.61) and SDS score (61.28 ± 1.52) compared with the control group (55.49 ± 3.37 and 63.08 ± 2.76), there were significant differences between 2 groups (P < .001). The jiao-tune of 5-element music can relieve the negative emotions in patients with decompensated HBV cirrhosis.

Theoretical and experimental study of plasmon oscillation dispersion in Si and Ge crystals

Plasma fluctuation dispersion has been theoretically and experimentally studied in monocrystal samples of Si (111) and Ge (111). It has been shown that the dispersion depends on crystallographic orientations of materials under study. In this work, the dispersion effects in the CLEE spectra, which manifest themselves in bulk samples of Si and Ge, have been studied. The loss energy electron was studied by the CLEE method upon their reflection from Si(111) and Ge(111) at different angles of incidence of the electron beam on the surface. Calculation of the total electron energy loss with formula (5) shows that the form of the CLEE spectrum of primary electrons depends on the nature and magnitude of the electron density in a given direction and is in satisfactory agreement with the experimental data. Thus, the theoretical and experimental results show that in the case of single-crystalline Si and Ge, with increasing k, the values of the bulk plasma oscillation increase by 2–3 eV.