Experimental Performance Evaluation Research Articles

Experimental and model evaluation of cyclic compressive performance for RAC-filled BFRP tube composite columns

The mechanical properties of recycled aggregate concrete (RAC) can be significantly enhanced in RAC-filled fiber-reinforced-polymer (FRP) tube composite columns. However, the cyclic compressive behavior of this type of composite columns has been scarcely studied. In this study, a series of cyclic axial compressive tests were conducted on RAC-filled basalt-FRP (BFRP) tube composite columns, and the effects of confinement level (number of BFRP layers) and RA replacement ratio were investigated. The test results indicate that, compared to RAC columns, the compressive capacity and deformability of RAC-filled BFRP tube composite columns increased significantly under cyclic loading. The compressive strength and ultimate strain of BFRP-confined RAC reached 1.42-3.98 times and 2.88-21.53 times those of unconfined RAC, respectively. The compressive strength and ultimate strain under cyclic loading were generally close to those under monotonic loading, with the compressive strength ratios averaging 1.052 and the ultimate strain ratios averaging 1.031. The enhancement efficiency of BFRP confinement increased progressively with increasing confinement level and/or RA replacement ratio. The envelope curves of the cyclic stress-strain curves resembled the stress-strain curves under monotonic loading. The reloading modulus (Ere) and residual modulus (Eun,0) continuously decreased as the unloading strain (εun) increased, while the plastic strain (εpl) increased almost linearly with εun. The values of Ere, Eun,0 and εpl were affected by the confinement level and RA replacement ratio. Finally, typical theoretical models for FRP-confined concrete were used to evaluate the cyclic stress-strain curves of RAC-filled BFRP tube composite columns.

Comprehensive evaluation of solar floating photovoltaic prospective in Saudi Arabia: Comparative experimental investigation and thermal performance analysis

Recently, floating photovoltaic systems have been regarded as a promising technology for producing clean energy by utilizing the surface of water bodies, such as lakes, rivers and oceans. This study introduces a comparative experimental study and energy performance evaluation of a 1.0 kW offshore floating photovoltaic (FPV) system and a nearby traditional ground-based PV system (GPV) installed in the eastern province of Saudi Arabia. The FPV system was deployed in the Arabian Gulf, 25 m off the coast, at an average depth of 1 to 1.5 m depending on tide, wave, and current intensity. The FPV system employs a strong novel eco-friendly platform structure made of recycled buoyant materials such as engineered plastic drums and wood. This system is anchored with tension cables and concrete blocks that can withstand the changing sea water conditions. The GPV system, on the other hand, was installed 150 m inland from the shore. Real-time monthly data monitoring and assessment indicated that FPV systems outperformed GPV systems in terms of lower PV panel surface temperatures, higher power output, and panel efficiency. Based on daily average back surface temperatures, FPV system temperature was decreased by 7.5 % to 21.34 % when compared to GPV. Moreover, the FPV system efficiency was also increased by 12.2 % when compared to the GPV system. This study aims to assist in promoting the applicability of solar floating photovoltaic systems to synergistically fulfill the requirements of sustainable electricity production for the arid costal community in Saudi Arabia and similar areas.

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.

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.

Performance assessment of a 30.26 kW grid-connected photovoltaic plant in Egypt

Abstract This paper presents an experimental analysis and performance evaluation of a grid-connected photovoltaic plant installed on the rooftop of the Electronics Research Institute in Cairo, Egypt. Cairo is classified as a hot-desert climate region according to the standard Koppen-Geiger climate classification system. Over a year, we monitored real-time data to assess key system performance metrics, such as energy yield, efficiencies, performance ratio, capacity factor, and losses. Based on the obtained experimental results, the highest final yield of 5.2498 hr/day was observed in the summer, whereas the lowest yield of 3.439 hr/day occurred in the winter months. The photovoltaic plant had an average annual system efficiency of 15.8%, while the photovoltaic and inverter had mean yearly efficiencies of 17.1% and 97.2%, respectively. The average annual performance ratio is 83.03%, and the capacity factor is 18.72%. The monthly total loss exhibited a linear rise alongside increasing ambient temperature and solar irradiance. The ambient temperature affected the system efficiency, photovoltaic efficiency, and performance ratio. The findings can help strengthen forecasts of future large-scale photovoltaic plants in hot desert climates. Moreover, they can guide the design, optimization, operation, and maintenance of new grid-connected photovoltaic systems.

Reinforced Nacre-Like MXene/Sodium Alginate Composite Films for Bioinspired Actuators Driven by Moisture and Sunlight.

MXene-based soft actuators have attracted increasing attention and shown competitive performance in various intelligent devices such as supercapacitors, bionic robots and artificial muscles. However, the development of robust MXene-based actuators with multi-stimuli responsiveness remains challenging. In this study, a nacre-like structure soft actuator based on MXene and sodium alginate (SA) composite films is prepared using a straightforward solvent casting self-assembly method, which not only enhances the mechanical performance (tensile strength of 72MPa) but also diversifies the stimuli responsiveness of the material. The composite actuators can be powered by external stimuli from renewable energy sources, from moisture inducing a maximum bending angle of 190 degrees at a relative humidity (RH) of 91%, and sunlight irradiation generating a maximum curvature of 1.45 cm-1 under 100mW cm-2. The feasibility of practical applications, including moisture-responsive flowers and walkers, sunlight-responsive oscillators, and smart switches, is demonstrated through comprehensive experimental characterization and performance evaluation. The work presented here provides insight into the design of robust actuators via the utilization and conversion of environmentally renewable energy sources.

Experimental Performance Evaluation of a Lightweight Additively Manufactured Hydrodynamic Thrust Bearing

In this paper, a lightweight additively manufactured (AM) fixed geometry hydrodynamic thrust bearing fabricated via laser powder bed fusion (LPBF) is experimentally compared to a traditionally manufactured cast aluminum alloy thrust bearing of similar design. The purpose of this study is to evaluate how weight-saving design features in the AM bearing affect active critical hydrodynamic performance parameters to better understand in-service viability. Under various static operating conditions, performance parameters such as hydrodynamic pressure distribution, minimum oil film thickness (MOFT), bearing temperature and increase in oil temperature are measured. Compared to the traditionally manufactured bearing, the AM bearing showed an average increase in minimum oil film thickness of 53%, an average increase in trailing edge hydrodynamic pressure of 116%, while exhibiting an average decrease in bearing temperature of 1%. Experimental results are compared to numerical simulation showing reasonably good agreement.

Experimental Investigation of Two-Pass Solar Dryer with V-Corrugated Absorber for Potato Slice Drying

Reducing the moisture level of food items can help prevent bacterial development and deterioration, extend shelf life, reduce packaging, and improve storage for convenient transportation. In this paper, a two-pass solar dryer with V-Corrugated absorber plate is developed. Its experimental performance evaluation in forced convection is carried out for potato chip drying. Various parameters like Hourly Variation of Solar Radiation Intensity, Temperature Distribution Curves inside Solar Dryer, Collector Efficiency Curve, Hourly Mass Loss of Potato Slices and Moisture Removal Comparison with Conventional Open Sun Drying Method are calculated and presented graphically. The peak temperature of the absorber plate reached 69.30C, and the air temperature at the collector outlet recorded the highest value at 57.50C. The average temperature difference of 28.580C is obtained for heat transfer by convection between the modified corrugated absorber plate and the air. An important finding in this experimental investigation was that there is an average 6.50C difference in temperature between the hot air exiting the collector and the air available at the bottom of the lower tray of the drying chamber, which should be reduced by applying means of avoiding heat loss. The highest collector efficiency is calculated as 88.9 % at 2 PM. The lowest efficiency is calculated at 9 AM as 66.8 %. The thermal inertia of the system adds to the collector efficiency in the last 2 hours of the experimentation and hence collector performs better than in the morning hours, though the insolation is nearly the same for the first and last two hours of sunshine. The percentage reduction in drying time was found to be 38.9 % for 50 % moisture removal from potato slices as compared to open sun drying.

Theoretical modelling and experimental evaluation of thermal performance of a combined earth-to-air heat exchanger and return air hybrid system

To both alleviate thermal saturation in surrounding soil and avoid indoor air pollution caused by closed-loop earth-to-air heat exchanger (EAHE) systems, this study proposes a hybrid mode that combines EAHE and return air (RA), i.e., the EAHE-RA system. A theoretical model was proposed to predict the thermal performance of EAHE-RA systems considering both sensible and latent heat transfer inside the EAHE. Full-scale experiments on both open-loop EAHE system and EAHE-RA system were carried out. The results indicated that the average cooling capacity of EAHE in EAHE-RA system was decreased by 1202.8 W (43.82 %) in summer compared to open-loop EAHE system, while the average cooling capacity recovery of return air was 645.4 W. In winter, the average heating capacity of the EAHE of EAHE-RA system was decreased by 394.1 W (48.91 %), while the average heating capacity recovery of the return air was 1021.7 W. Theoretical predictions of EAHE outlet and indoor air temperature agree well with the measured ones in both summer and winter. Theoretical results indicated that the EAHE-RA system has lower/higher pipe wall temperatures in summer/winter than the open-loop EAHE does, indicating a lower thermal interference on surrounding soils and thus better durability.

Strengthening the activity and CO tolerance with bi-component PtNi/NbN-C catalyst for methanol alkaline electrooxidation

It is critical to create the anodic catalysts with high efficiency and economy for direct methanol fuel cells (DMFCs). Here, a series of PtNi/NbN-C catalysts (M=Co, Sn, Ni) are developed using the glycol solvothermal process, to investigate the catalytic effficiency for alkaline methanol oxidation reaction (MOR). Catalytic performance evaluation experiments show that the doped Ni species bring the enhancement effect on Pt/NbN-C for the alkaline MOR. The mass activities of PtxNiy/NbN-C show a volcanic trend with the increased Ni contents. PtNi/NbN-C has the highest mass activity (6025.5 mA·mg-1Pt) for alkaline MOR, 18.3 times greater than that of the Pt/C commercial catalyst. The LSV, EIS, Tafel, CA and CO stripping results imply PtNi/NbN-C also exhibits the lowest onset potential, charge transfer resistance, fastest kinetics, highest CO tolerance and stability. When the XRD, HRTEM, and XPS analysis are combined, it is discovered that the electronic effect between the Pt, Ni, and NbN species is mostly responsible for the catalytic performance enhancement is mainly depend on the electronic effect among the Pt, Ni and NbN species. The presence of Pt in an electron-deficient state can enhance the conversion of adsorbed methanol and intermediates, evidenced by a direct relationship between the d-band centers and the mass activities for MOR of different catalysts. This study may provide guidance for the development of anodic materials for DMFCs.

Research on the Design of Medical Imaging Assisted Diagnosis System Based on Machine Learning

The design and application of medical imaging diagnostic assistance systems have become an indispensable facet of modern medicine. Technologies based on machine learning can handle vast and intricate medical imaging data, offering precise diagnostic support and significantly enhancing the efficiency and accuracy of clinical diagnoses. This study focuses on the development and implementation of an efficient medical imaging diagnostic assistance system utilizing machine learning algorithms such as Principal Component Analysis (PCA), Support Vector Machines (SVM), and Multi-Layer Perceptrons (MLP). Through the architectural design of intelligent diagnostic assistance systems, data preprocessing, and feature vectorization, combined with the application of classification algorithms, a robust diagnostic support system capable of addressing diverse medical scenarios has been constructed. Performance evaluation experiments indicate that this system demonstrates high accuracy and robustness in processing medical imaging data, holding potential for clinical implementation. The findings of this study provide new insights for the advancement of intelligent diagnostic systems in medical imaging and lay a solid foundation for the development of future clinical diagnostic tools.

In vitro cytotoxicity activity (MTT assay), experimental spectral investigations, quantum computational, solvents performance, and biological evaluation on N-tert-Butoxycarbonylimidazole

N-tert-Butoxy carbonyl imidazole is investigated computationally and compared with experimental results. Also, vitro assay studies are done. Computational techniques are cost effective and less time-consuming process. DFT techniques with basis set B3LYP are executed on the title compound which gives accurate and efficient results thus significant in drug design. Optimized geometry is developed and for detailed geometry FT IR, FT RAMAN are done. UV, FMO, NLO, NBO are the studies carried out to get electronic properties of N-tert-Butoxy carbonyl imidazole. Studies with Different green solvents such as water, DMSO with IEFPCM solvation model are carried out along with gas phase. LOL, ELF, MEP and RDG studies are done for topological analysis. Experimental studies such as FT IR, FT RAMAN, UV were done in supporting theoretical results. Drug likeness, Molecular docking studies are done in analyzing biological activity of N-tert-Butoxy carbonyl imidazole. Results suggests that this compound has a good potential in treating cervical cancer and nontoxic in nature. Also, vitro assay studies are done on the title compound and cytotoxicity has been identified.

Experimental Performance Evaluation of a Multi-stream Heat Exchanger for Integration of High-Temperature Steam Electrolysis with Nuclear Reactor Systems

Experimental Performance Evaluation of a Multi-stream Heat Exchanger for Integration of High-Temperature Steam Electrolysis with Nuclear Reactor Systems

Experimental evaluation and artificial neural network modeling of heat transfer performance of aerosolized magnesium oxide nanoparticles flow through pipes

This study presents a novel approach to modeling the convective heat transfer coefficient (CHTC) of aerosolized magnesium oxide (MgO) nanoparticles in a circular pipe using artificial neural network (ANN) technique, by leveraging experimental data. The work addresses a gap in existing research on the heat transfer characteristics of nanoaerosols under varying thermal and flow conditions. MgO nanoparticles (30-50 nm) were dispersed in compressed air at volume fractions of 0.005, 0.01, and 0.05 to generate the nanoaerosol. This aerosol was then driven through the pipe at volumetric flow rates between 10 and 50 liters per minute (lpm). The pipe was subjected to controlled heat fluxes of 4546.83 W/m², 9093.66 W/m², and 13640.49 W/m² to evaluate the aerosol heat transfer coefficient (AHTC). Experimental results demonstrated that incorporating MgO nanoparticles significantly enhanced the heat transfer coefficient by up to 1.4 %, 111 %, and 89.7 % at the specified heat flux values, corresponding to increases in the volumetric flow rate from 10 lpm to 50 lpm, respectively. An ANN-based correlation was developed to model the heat transfer coefficient in relation to heat flux, particle volume fraction, and volumetric flow rate. This model accurately predicted the experimental data, achieving a mean absolute percentage error (MAPE) of 9.9 × 10-5, a mean square error (MSE) of 0.038433, and a coefficient of determination (R²) of 0.99. These findings confirm the ANN model's efficacy in predicting the enhancement of the nanoaerosol heat transfer coefficient and provide a robust tool for future thermal management applications involving nanofluids.

An Experimental Evaluation of Compressive Performance of Cement Based Materials with Graphene Oxide Nanosheets (GO) and Ground Granulated Blast Furnace Slag (GGBS)

An Experimental Evaluation of Compressive Performance of Cement Based Materials with Graphene Oxide Nanosheets (GO) and Ground Granulated Blast Furnace Slag (GGBS)

Performance evaluation and physical simulation experiment of SiO2 nanoparticle synergistic crosslinked polymer system

Abstract As natural gas development gradually shifts from early to mid to late stages, water outflow from gas wells has become an inevitable problem. In this study, polyethyleneimine cross-linked polymers were synthesized and nano particles were introduced to obtain SiO2 nanoparticle synergistic cross-linked polymer systems. Rheological experiments show that the system has stronger shear resistance and higher yield stress, and the linear viscoelastic region has a stress amplitude less than 3.5Pa, exhibiting good elastic properties in the range of 0.01 to 10Hz. In terms of stability, after 45 days of aging, the viscosity retention rate of the system is 77.66%. When the mineralization degree is 224852mg/L, the viscosity retention rate is greater than 76.33%, indicating that the system has good aging stability and salt resistance.The physical simulation experiment of core displacement shows that SiO2 nanoparticle synergistic cross-linked polymer gel has gas-water selective plugging ability, and the reduction of water phase permeability is much greater than that of gas phase. The gas phase permeability can remains at about 75%, which is 2300 times that of water phase permeability, and has a good water plugging effect.

Application of Low-Temperature Temporary Plugging Agents in Coalbed Methane Volume Fracturing

Currently, unconventional oil and gas fields employ volume fracturing technology, and temporary plugging and diversion techniques have become one of the main methods for increasing production. The Mixi coalbed methane block in Yibing has a formation vertical depth of 800-1000 meters and a relatively low average formation temperature of 30 degrees Celsius. The temporary plugging agents currently in use face challenges during reservoir stimulation, including difficulty in withstanding pressure differentials, poor degradability, and significant reservoir damage, resulting in unsatisfactory implementation effects. Therefore, the water-soluble temporary plugging agent RD-1 was selected as the preferred option. Laboratory performance evaluation experiments have demonstrated that this temporary plugging agent exhibits good sealing and degradation properties. Field trials have shown good temporary plugging and diversion effects, with noticeable pressure increase during plugging and significantly improved stimulation volume. It has demonstrated good applicability in coalbed methane volume fracturing, accumulating valuable experience for efficient development of this block.

Nest-shaped hollow-encapsulated Pd catalyst enhances the catalytic performance of hydrogen peroxide directly synthesizing from hydrogen and oxygen

A well-defined structural morphology can significantly construct a special catalytic micro-reaction environment to enhance the catalytic performance of Pd catalyst in the direct synthesis of hydrogen peroxide from hydrogen and oxygen (DSHP). In this study, SiO2 was used as a rigid template, PdCl2 as the Pd precursor, and dopamine hydrochloride (DA) as the carbon and nitrogen source to synthesize a nest-shaped hollow-encapsulated Pd catalyst named PdMulti@ONHCS. This catalyst was successfully constructed via high-temperature pyrolysis of poly dimethyl diallyl ammonium chloride (PDDA), which generated a blasting effect crucial for this formation. Characterization analysis, catalytic performance evaluation experiment, and molecular dynamics simulation were conducted to explore the structure-performance relationship of PdMulti@ONHCS catalyst in DSHP. Both experimental and simulation results consistently showed that the nest-shaped hollow structure of PdMulti@ONHCS catalyst created a distinctive catalytic microreactor environment with a spatial mass transfer constraint, which was not only conducive to adsorption and enrichment of H2 and O2 at Pd active sites to produce H2O2. In addition, the generated H2O2 can be desorbed from Pd active sites in time and rapidly diffused into the reaction solution, effectively inhibiting the dissociation of species containing OO bonds on the Pd surface, resulting in severe hydrogenation and decomposition side reactions, and improving H2O2 productivity and selectivity.

Experimental study and performance evaluation of R744 thermal management systems with enhanced parallel cooling for electric vehicles

As worldwide environmental concerns grow, R744 (CO2) has become one of the preferred refrigerants in electric vehicle (EV) thermal management system due to its environmentally friendly characteristics. This study presents the development and evaluation of an Enhanced Parallel Cooling (EPC) system, a novel advancement designed to optimize the performance of R744 thermal management systems in EVs. A series of experiments are carried out to investigate the effects of key operating variables such as the coolant flow rate, and air velocity on the system efficiency. Meanwhile, Response Surface Methodology (RSM) is employed to determine the optimal control contour map under various environmental conditions. The maximum cooling capacity of the EPC system in supercharging mode is experimentally evaluated. Furthermore, a comparative analysis of driving range improvement under the Urban Dynamometer Driving Schedule (UDDS) and the Highway Fuel Economy Test (HWFET) cycles is carried out. With the help of the Series Cooling Unit (SCU) in the EPC system, the maximum cooling capacity increases by 27.8 % to 9.89 kW, and the driving range increases by up to 14.6 km. The findings underscore the potential of the innovative R744 thermal management system architecture to improve operational efficiency and extend the driving range of EVs.

Energy absorption assessment of recovered shapes in 3D-printed star hourglass honeycombs: Experimental and numerical approaches

This study provides an experimental and numerical evaluation of the energy absorption performance of a 3D-printed star hourglass honeycomb structure with a novel design made from pure and reinforced PLA by chopped carbon fibers and continuous glass fiber. The study further investigates the energy absorption response of this structure after the shape recovery due to thermal stimuli under the quasi-static compressive loading. As an additive manufacturing process, Fused Deposition Modeling is used to produce the specimens with pure and reinforced PLA filament. The difference in the nonlinear response of PLA due to plasticity and damage in tension and compression loading directions, as a feature that helps the shape recovery, is considered in mechanical response analysis using the Finite Element approach. Then, in the obtained results distinguish constitutive laws in tension and compression mechanical properties are employed leading to a failure model using the appropriate algorithm consistent with the experiments. According to the obtained results which reveal good agreement regarding the experimental results, by designing appropriate auxetic configuration selecting suitable geometry parameters, and employing the proper material with diverse properties in tension and compression directions, it is possible to fabricate a lattice structure inherits the shape recovery after the compression deformation which exhibits acceptable energy absorption performance even the second shape recovery.