Experimental Performance Evaluation Research Articles

Experimental analysis and performance evaluation of a solar PV-driven diffusion absorption refrigeration system

Experimental analysis and performance evaluation of a solar PV-driven diffusion absorption refrigeration system

Experimental evaluation of downlink communication performance of IEEE 802.11ax wireless LAN: OFDM vs. OFDMA

Experimental evaluation of downlink communication performance of IEEE 802.11ax wireless LAN: OFDM vs. OFDMA

A bipolar high‐voltage pulse driver for air‐coupled ultrasonic defect detection in soft‐pack lithium battery

AbstractDeveloping a high‐performance transducer driver is essential yet challenging for air‐coupled ultrasound applications. This study introduces a MOSFET‐based bipolar high‐voltage pulse driver designed for defect detection in soft‐pack lithium batteries. High‐voltage DC generation is achieved through a push–pull inverter and full‐wave voltage multiplier circuit, producing a stable DC output. High‐speed MOSFET switching then controls the charging and discharging of a capacitor in an RC network, generating a symmetric bipolar high‐voltage pulse signal with a peak‐to‐peak voltage of 1104 V at 100 kHz. Performance evaluation experiments demonstrated that a 7‐cycle pulse train provides an optimal balance of signal penetration and time resolution, effectively preventing waveform overlap. The system reliably penetrates soft‐pack lithium batteries up to 6 mm thick, and detects internal lithium battery defects, such as 1 mm air bubbles. Overall, this bipolar high‐voltage pulse driver surpasses traditional designs in both time and frequency domains, offering enhanced detection accuracy and practicality for air‐coupled ultrasonic inspection of lithium battery defects.

Evaluation of emissions and performance of a diesel engine running on graphene nanopowder and diesel-biodiesel-ethanol blends.

Today, there are environmental problems all over the world due to the emission of greenhouse gasses caused by the combustion of diesel fuel. The excessive consumption and drastic reduction of fossil fuels have prompted the leaders of various countries, including Iran, to put the use of alternative and clean energy sources on the agenda. In recent years, the use of biofuels and the addition of nanoparticles to diesel fuel have reduced pollutant emissions, improved the environment, and enhanced the physicochemical properties of the fuel. The current research deals with the experimental evaluation of emissions and performance of a diesel engine running on graphene nanopowder together with diesel-biodiesel-ethanol blends. The engine variables studied included the engine speed (in three stages 1800, 2200, and 2600rpm) and three types of fuel including graphene nanoparticles (with values of 25 and 50ppm), biodiesel (with volume percentages of 4, 6, and 8), and ethanol (with volume percentages of 2 and 4). The results showed that the power and torque of the D86 + B8 + E6 + G50 fuel increased on average by 20.26% and 28.76% at all engine speeds compared to the D100 fuel. The use of D86 + B8 + E6 + G50 fuel resulted in a significant reduction in CO (38.84%), UHC (21.24%), and NOx (19.92%) emissions compared to D100 fuel. In addition, a significant increase in CO2 emissions (23.19%) was observed. The results of this study clearly show that the use of biofuels and the addition of nanopowder to D100 fuel are very effective methods to improve combustion, performance, and emission characteristics in diesel engines.

An experimental and numerical evaluation of the structural performance of bamboo-reinforced concrete beams

The global shift toward sustainable construction calls for eco-friendly alternatives to traditional materials. While steel reinforcement in concrete offers high strength and durability, it has significant environmental and economic drawbacks. Bamboo, a fast-growing and renewable material, is a low-cost, eco-friendly option, but concerns about its structural performance have hindered its widespread use. This study examines the structural performance of concrete beams reinforced with steel (SRC), bamboo (BRC), and hybrid steel-bamboo combinations (HYB-1 and HYB-2). It assesses ultimate failure load, load–deflection curves, failure modes, and crack patterns to explore their viability as sustainable alternatives. Beams measuring 150 × 150 × 750 mm were tested experimentally and simulated using ABAQUS software under three-point bending. SRC beams had the highest ultimate failure load (104.67 kN) and deflection (8.6 mm). BRC beams had the lowest failure load (17.97 kN), a decrease of 82.9% compared to SRC beams. HYB-1 and HYB-2 showed intermediate loads of 87.25 kN and 24.99 kN with a decrease of 16.6% and 76.1% respectively compared to SRC reference samples. Deflection in BRC beams was the least (3.0 mm), while HYB-1 and HYB-2 showed deflections of 7.4 mm and 5.6 mm. The average flexural strength for BRC beams was 82.8% lower than SRC beams, while HYB-1 and HYB-2 showed reductions of 16.9% and 76.1%. The energy absorption capacity of HYB-1 beams was close to SRC beams, with only a 29.1% reduction, while BRC and HYB-2 beams showed a reduction of 92.8% and 87.1% respectively compared to SRC beams. These findings suggest that hybrid configurations, particularly HYB-1, balance structural strength and sustainability Finite element analysis (FEA) closely matched experimental results, with an average difference of 7.44%, validating the accuracy of the modeling.

Comparative study of state-of-the-art metaheuristics for solving constrained mechanical design optimization problems: experimental analyses and performance evaluations

Abstract Many challenges are involved in solving mechanical design optimization problems related to the real-world, such as conflicting objectives, assorted design variables, discrete search space, intuitive flaws, and many locally optimal solutions. A comparison of algorithms on a given set of problems can provide us with insights into their performance, finding the best one to use, and potential improvements needed in their mechanisms to ensure maximum performance. This motivated our attempts to comprehensively compare eight recent meta-heuristics on 15 mechanical engineering design problems. Algorithms considered are water wave optimizer (WWO), butterfly optimization algorithm (BOA), Henry gas solubility optimizer (HGSO), Harris Hawks optimizer (HHO), ant lion optimizer (ALO), whale optimization algorithm (WOA), sine–cosine algorithm (SCA) and dragonfly algorithm (DA). Comparative performance analysis is based on the solution trait obtained from statistical tests and convergence plots. The results demonstrate the wide range of adaptability of considered algorithms for future applications.

Experimental performance evaluation of feedback resistors and capacitors for indoor visible light communication system under realistic illumination setup for divergent optical power levels

Experimental performance evaluation of feedback resistors and capacitors for indoor visible light communication system under realistic illumination setup for divergent optical power levels

Experimental Performance Evaluation of a Dual-purpose Photovoltaic-thermal System with Phase Change Material for Passive Heating and Cooling

Photovoltaic thermal technology (PVT) is gaining increasing attention due to its improved performance and reliability made possible by continuous technological advances. Despite these significant advances, the potential of PVT modules to simultaneously heat, cool and generate electricity passively remains unexplored. In this study, we developed a dual-purpose PVT collector that can passively heat and cool to improve both electrical efficiency and thermal energy management, without relying on external power supply. By using CaCl2-6H2O as an inorganic phase change material (PCM), the latent heat of fusion of the PCM passively cools the circulating air and thus improves the electrical efficiency of the PVT module. The cooling and heating performance of the system was analyzed using CFD (Computational Fluid Dynamics) simulations conducted with ANSYS FLUENT. Subsequently, the experimental performance of the system was evaluated in two periods — September and December — in a greenhouse under the climate conditions of Tehran, Iran. The results showed an 11.28% increase in cooling efficiency and a 4.23% improvement in power generation efficiency for the PVT-PCM collector, while an 18.86% improvement in heating efficiency was achieved over a longer period. In September, the observed cooling efficiency was12.92%,1.64% below the value predicted by the simulations. While the simulations calculated a heating efficiency of 20.31%, the tests conducted in December showed an actual efficiency of 18.86%. During the night-time heating, the PCM solidified in 130 minutes, while the simulations predicted a solidification time of 120 minutes. The predicted and actual values showed a strong correlation, with an R-squared value of 0.9923. These results underline the effectiveness of the passive cooling and heating system in greenhouses and demonstrate its ability to improve electrical efficiency.

Sugarcane-Based Polyethylene Biocomposite Reinforced with Organophilic Montmorillonite Clay: Experimental Characterization and Performance Evaluation.

With the growing human awareness of trying to reduce the environmental impact in today's world, the development of new sustainably based materials has been the increasing focus of industry and academia. Biocomposites are environmentally friendly materials produced from raw materials synthesized from renewable sources. In this sense, this work aims to characterize and evaluate the mechanical and thermal performances of biocomposites manufactured from a thermoplastic matrix of high-density bioethylene and obtained from ethanol produced from sugarcane and reinforced with organophilic montmorillonite clay. For this, polyethylene grafted with maleic anhydride (PE-g-MA) was used as a compatibilizer. Dry biocomposites with 1, 3, and 5% organophilic montmorillonite clay, by weight, were subjected to structural (FTIR and DRX), thermal (DSC), thermogravimetric (TG/DTG), thermodynamic-mechanical (DMA), morphological (SEM and MET), and mechanical (tensile, flexural, impact, and shore D hardness tests) characterizations. The DMA experiments were carried out within the viscoelastic region of the polymer. From the obtained results, we notice that, in general, there was an increase in the properties of high-density biopolyethylene (B-HDPE) (without compromising its processability), and therefore, the automotive application of biocomposites compatible with PE-g-MA, containing low levels of organophilic montmorillonite clay, is recommended.

AutoMine: A Multimodal Dataset for Robot Navigation in Open‐Pit Mines

ABSTRACTIn the past decade, autonomous driving has witnessed significant advancements, largely attributable to the evolution of precise algorithms and efficient computing platforms. Nevertheless, the open‐pit mine, a typical scenario within closed‐field environments, has garnered limited attention in autonomous driving, primarily owing to the scarcity of data and experimental benchmarks. This work presents original data collected from five platforms, comprising one passenger vehicle, three wide‐body trucks, and one mining truck, across eight different mining sites. We provide a comprehensive elucidation of platform types, sensors, calibration methodologies, synchronization techniques, data collection approaches, and a thorough analysis of the data characteristics. In addition, we offer a detailed benchmark comparison of short and long odometry and navigation performance across multiple vehicles in open‐pit mines. With comprehensive data characteristics, experimental performance evaluations, and thorough analysis, we believe that this work establishes a robust research foundation for navigation and fusion methods in open‐pit mines, thereby constituting a significant contribution to the autonomous driving and field robotics communities.

Modified REL-Based Piecewise Path Loss Modeling Approach for Shore-to-Ship Communication at 5.6 GHz

The need for reliable and uninterrupted communication systems in the marine environment has become critically important with increasing maritime activities, environmental monitoring, and the spread of autonomous systems. However, the complex structure of electromagnetic wave propagation in a sea environment limits the accuracy of the existing propagation models. Thus, the Modified Round Earth Loss (REL) model was first developed in this study to estimate the path loss more accurately in shore-to-ship communication. Subsequently, a piecewise modeling approach based on the principle of two-segment data modeling was proposed. In the Modified REL model, unlike the traditional REL model, the paths and gains of the direct and reflected waves were not considered equal in the calculations. Moreover, unlike in the classical approach, the receiver height was not taken as a fixed value; the estimated best receiver height value for each measurement was included in the calculations as a representation of the effect of roughness in the sea environment. Thus, the model is better adapted to various environmental conditions. In addition, the proposed piecewise model divides the propagation medium into two regions using a break point calculated by Fresnel zone theory. The Modified REL model was used for the first region and the log-distance model was used for the second region. This method allows for more accurate modeling of signal behaviors, especially at different distances. Experimental measurements and performance evaluations conducted using four different shore-to-ship communication scenarios show that the Modified REL model shows an average improvement of up to 3% in Root Mean Square Error (RMSE) values compared to the classical REL model. Additionally, the proposed piecewise model improves the fitting error of the Modified REL model, which models the data as a single whole, by an average of 22.25%. These findings emphasize the necessity of propagation models that are sensitive and adaptable to environmental changes for maritime communication.

Far-focus compound ultrasound imaging with lag-one coherence-based zero-cross factor.

Ultrasound imaging has been widely used in clinical examination because of portability, safety, and low cost. However, there are still some main challenges of imaging quality that remain in conventional ultrasound systems. Improving image quality of SA-based methods using an improved imaging mode named far-focus compound (FSC) imaging. A far-focus compound (FSC) imaging based on full-aperture transmission and full-aperture reception is proposed in this paper. In transmission, it uses the full aperture to transmit the focused beam to ensure image resolution and emission of sound field energy. In reception, the full aperture is used to receive the reflected beam to ensure the image quality. A lag-one coherence-based zero-cross factor (LOCZF) is then implemented in FSC for improvement of contrast ratio (CR). The LOCZF uses lag-one coherence as zero-cross factorâs adaptive coefficient. Comparisons were made with several other weighting techniques by performing simulations and experiments for performance evaluation. Results confirm that LOCZF applied to FSC offers a good image contrast and simultaneously the speckle pattern. For simulated cysts, CR improvement of LOCZF reaches 194.1%. For experimental cysts, CR improvement of LOCZF reaches 220%. From the in-vivo result, compared with FSC, CR improvement of LOCZF reaches 112.7%. Proved gCNR performance. In addition, the LOCZF method shows good performance in experiments. The proposed method can be used as an effective weighting technique for improvement of image quality in ultrasound imaging.

Research on the Designing and Experimental Performance Evaluation of a New Sand Control Screen for Argillaceous Fine Silt Gas Hydrate Reservoirs

Argillaceous fine silt hydrate reservoirs have a clay content of 20–25% and a median sand particle size of 10–15 um. Sand control is extremely difficult, restricting the continuous and stable testing of gas hydrate. This paper focuses on the sand production mechanisms, plugging characteristics, and clogging mechanisms of these hydrate reservoirs. Based on the actual characteristics of hydrate reservoirs, it presents an understanding of the sand production mechanism of argillaceous fine silt. The characteristics and properties of three different sand control methods and six kinds of sand control screens are analyzed. Clear design concepts for sand control screens in argillaceous fine silt hydrate reservoirs are proposed. Two types of new sand control screen with metal filter screens and pre-filled screens have been innovatively designed, and the sand control ability and overflow performance of the screens are evaluated using the meter production index conversion method. Sand production simulation and comprehensive experimental evaluation and analysis of the flow performance of seven kinds of screens (themselves from two categories of screens) were carried out using a self-made special experimental testing device. The experimental results show that the newly designed screens have good flow performance and can meet the requirements of a certain gas production rate. Specifically, Class A metal screens (60/70 mesh) and Class B pre-filled screens (40/70 mesh) have excellent sand control capacity and flow performance, with 10 g sand output and 300 L total water output, thus fulfilling the sand control requirements and achieving the purpose of “effective sand control, prevention without plugging, and continuous stable production” of argillaceous fine silt gas hydrate reservoirs. They therefore provide a reference for future research on sand control and new screen designs for argillaceous fine silt hydrate reservoirs.

Experimental evaluation of temporary plugging performance and mechanism analysis of degradable preformed particle gel based on NMR technology

Utilizing chemical temporary plugging systems to further increase the stimulated reservoir volume (SRV) and improve oil recovery (IOR) has become a hot topic in the current petroleum industry. Pre-formed gel particles (PPG) possess excellent swelling properties and can form high-strength plugging in high-permeability channels. In addition, degradable pre-formed gel particles (DPPG) further exhibit self-degradation characteristics and excellent temporary plugging and fluid diverting performance. In our previous studies, we examined the temporary plugging mechanisms of DPPG prepared with different molecular weight (MW) of crosslinking agents (PEGDA) through bottle tests and core displacement experiments. However, the microscopic swelling mechanism and temporary plugging mechanism in pore throats of reservoir cores are still unclear. In this paper, comprehensive research was conducted on the microscopic temporary plugging mechanism of DPPG prepared with different MW crosslinking agents using both and method. Results showed that DPPG with different compositions had different micro-swelling performance. NMR-T2 analysis for bottle test showed that DPPG-M1 (with the smallest MW of crosslinking agent) gradually decreased in nuclear signal during the water absorption and swelling process, and had the largest swelling volume and swelling rate. On the other hand, DPPG-M5 (with the largest MW of crosslinking agent) exhibited a slow diffusion process of surface water towards the nucleus, resulting in the smallest swelling volume and swelling rate. However, its complete degradation time was longer. Moreover, the NMR T2 (i.e., spin-spin relaxation time) results of the cores in the dynamic temporary plugging experiment showed that the decrease of the MW of the crosslinking agent enhanced the plugging performance, but with less damage to the formation. The MRI images confirmed that DPPG-M5 had better injection capability in the core and caused greater damage to the core. The research results of this study showed that NMR technology can reveal the temporary plugging mechanism of DPPG from a micro-level perspective.

Design and modelling of a novel single-phase-driven piezoelectric actuator

Sandwich single-phase-driven piezoelectric actuators have attracted increasing interest owing to their simple control circuits, flexible designs, and high output forces. However, there are challenges in constructing a standing-wave driving mode for sandwich single-phase-driven rotary piezoelectric actuators and in achieving bidirectional driving as well as an integrated structural and functional design, which limit their applications. To address these issues and meet the demands of the joint drive, a novel sandwich single-phase-driven rotary piezoelectric actuator is proposed in this study. The actuator stator has a beam-ring configuration, with dual rotors effectively integrated with a preload adjustment mechanism to solve the contact-warping problem of the cantilever joint and achieve an integrated structural and functional design of the joint drive. The standing-wave rotation drive and steering functions are realized through the special design of modes and unique arrangement of the upper and lower driving teeth. To reveal the dynamic characteristics of the stator, a universal electromechanical coupling dynamic model for the torsional-bending composite vibration of sandwich piezoelectric actuators was developed for the first time using the transfer matrix method, and the correctness of the dynamic model was verified using a prototype of the proposed stator. Finally, the structural design feasibility of the proposed piezoelectric actuator was verified through performance evaluation experiments on the actuator prototype. The proposed sandwich single-phase-driven rotary piezoelectric actuator lays the technical and theoretical foundations for achieving simple, fast, efficient, and precise driving and control of robotic joints.

Experimental and numerical the effect of cavitation detection on hydraulic performance of the centrifugal pump based on different geometrical configurations

The cavitation phenomena and its experimental evaluation of hydraulic pump performance are the subjects of this study. Both qualitative and quantitative assessments of a pump's flow structure were carried out. The unsteady flow in a pump with various impeller geometry characteristics was investigated numerically. In-depth examinations of the local flow parameters for the static pressure, pump head, vapour volume variation fraction, and pressure fluctuations in the time and frequency domains were conducted. The findings showed that the low-pressure region that closed the impeller eye close to the leading edge of the blade is where the cavitation phenomena takes place. Additionally, the results showed that the blade passing frequency (BPF) and the pump's rotational frequency (RF) are two significant dominant frequencies in the device. Furthermore, the numerical results show that modest cavitation occurred at the design mass flow for Z=3, 4, 5, 6, and 7 impeller blades.

In Situ Experimental Analysis and Performance Evaluation of Airport Precast Concrete Pavement System Subjected to Environmental and Moving Airplane Loads.

The behavior of airport precast concrete pavement (APCP) involving new design and construction concepts was experimentally analyzed under environmental and moving airplane loads, and the long-term performance of the APCP was evaluated using fatigue failure analysis. The strain characteristics and curling behavior of the APCP under environmental loads were comprehensively analyzed. The APCP slabs exhibited a pronounced curling phenomenon similar to conventional concrete pavement slabs. The dynamic response of the APCP subjected to impact loads was analyzed by performing heavy weight deflectometer tests. The test results confirmed that the vertical deformation of the APCP was small and within the typical range of vertical deformation of conventional concrete pavement. The dynamic strain response of the APCP under moving airplane loads was then analyzed and the strain variation during day and night times was compared. The strains during the day were found to be significantly larger than those at night under airplane loads because of the curling phenomenon of the APCP slabs. Finally, the long-term performance of the APCP was evaluated using fatigue failure analysis based on the obtained behavior. Even using the most conservative fatigue failure prediction model, the service life of the APCP was ascertained to be more than 30 years. Based on the overall results of this study, it is concluded that the APCP, which is designed to reduce slab thickness by placing reinforcing bars in the slabs via reinforced concrete structural design, exhibits typical behavior of concrete pavements and can be successfully applied to airport pavement rehabilitation.

Parametric Study on Structural Performance According to the Condition Grade of Open-cut Electric Power Tunnel

In this study, the structural performance of electric power tunnels was evaluated based on the type and degree of damage. For experimental performance evaluation, a power structure test specimen was designed with a state safety performance of grade D corresponding to a concrete damage area ratio of 44% and structural safety performance of grade D with a reduced cross-section of 25% of the main reinforcement of the upper slab. The electric power structures with grade D state safety performance and structural safety performance exhibited 63% load-bearing capacity compared to those without damage. Cracks occurred on the outside of the structure under the experimental conditions simulating the overburden load, implying the possibility of corrosion of the outer reinforcing bars of the real structure. Finite element analysis showed that reducing the area of the outer main rebar of the upper slab caused more significant reduction in the load-bearing capacity than that of the inner main rebar.

An optimized dynamic attribute-based searchable encryption scheme.

Cloud computing liberates enterprises and organizations from expensive data centers and complex IT infrastructures by offering the on-demand availability of vast storage and computing power over the internet. Among the many service models in practice, the public cloud for its operation cost saving, flexibility, and better customer support popularity in individuals and organizations. Nonetheless, this shift in the trusted domain from the concerned users to the third-party service providers pops up many privacy and security concerns. These concerns hindrance the wide adaptation for many of its potential applications. Furthermore, classical encryption techniques render the encrypted data useless for many of its valuable operations. The combined concept of attribute-based encryption (ABE) and searchable encryption (SE), commonly known as attribute-based keyword searching (ABKS), emerges as a promising technology for these concerns. However, most of the contemporary ABE-based keyword searching schemes incorporate costly pairing and computationally heavy secret sharing mechanisms for its realization. Our proposed scheme avoids the expensive bilinear pairing operation during the searching operation and costly Lagrange interpolation for secret reconstruction. Besides, our proposed scheme enables the updation of access control policy without entirely re-encrypting the ciphertext. The security of our scheme in the selective-set model is proved under the Decisional Bilinear Diffie-Hellmen (DBDH) assumption and collision-free. Finally, the experimental results and performance evaluation demonstrate its communication and overall efficiency.

Experimental performance evaluation of direct cooling of hot stamping dies using fractal cooling channels

Hot stamping is a promising technology to reduce carbon dioxide emissions in the transportation industry by decreasing the weight of components with appropriate strength. However, the low cooling performance of conventional indirect cooling channels degrades the product quality and production rate during hot stamping. This study proposes a novel direct cooling system for hot stamping dies with fractal cooling channels (FCCs). Based on experiments, the cooling performance of the FCC was analyzed at various press holding times, mass flow rates, and cycle numbers. In the FCC, the average blank temperature at a water mass flow rate of 50 kg h−1 was 22 % lower than that at a zero-mass flow rate. At a mass flow rate of 50 kg h−1, the average blank temperature in the FCC increased with the cycle number and converged to 186 °C in the seventh cycle. Additionally, the standard deviation of the temperature distribution in the FCC was on average 39 % lower than that in the straight cooling channel (SCC). Finally, the daily production rate in the FCC was 34 % higher than that in the SCC.