Experimental Performance Analysis Research Articles

Experimental investigation and performance analysis of a spray-type ionic liquid desiccant dehumidifier

Ionic liquid desiccants (ILDs) have vapor pressures similar to lithium chloride and no corrosion and crystallization problems, so they are considered a promising alternative to halide salt desiccant solutions. However, the cost of ILDs is more expensive than conventional halide salts, which limits their practical application. Thus, this study developed a spray-type dehumidifier using an ionic liquid desiccant to increase dehumidification performance and reduce the required amount of ILDs. The presented dehumidifier was tested at various operating conditions. Also, a theoretical model was established to analyze heat and mass transfer coefficients of the dehumidifier. Results indicate that the increase in the flow rate ratio of solution to air benefits absorption performance, and the mass flux of solution is suggested to exceed 170 mL s−1 to avoid the occurrence of air bypass. Moreover, compared with the packed bed type, the spray type can reduce the required solution flow rate by 35 % and save power consumption by 19 % under the same moisture removal rates. The dehumidification effectiveness of the presented dehumidifier was up to 0.64 and comparable to the conventional packed bed dehumidifier using lithium chloride solutions.

Electromechanical Performances of Polyvinyl Chloride Gels Using (Polyvinyl Chloride-Co-Vinyl Acetate) (P(VC-VA)) Synergistic Plasticization.

The current polyvinyl chloride (PVC) gel flexible actuators are facing challenges of high input voltage and an insufficient elastic modulus. In this study, we conducted a detailed study on the properties of PVC gel prepared by introducing the modifier polyvinyl chloride-vinyl acetate (P(VC-VA)). We compared a modified PVC gel with the traditional one in terms of the relative dielectric constant, mechanical modulus, and electromechanical actuation performance. Experimental results demonstrated that the introduction of P(VC-VA) enhanced the dielectric constant and reduced the driving electric field strength of PVC gels. The dielectric constant increased from 4.77 to 7.3. The electromechanical actuation performance increased by 150%. We employed the Gent model to fit the experimental results, and the actual experimental data aligned well with the expectations of the Gent model. The research results show that this type of plasticizing method effectively balanced the mechanical and electrical performance of PVC gels. This study summarizes the experimental results and performance analysis of PVC gels prepared using innovative plasticization methods, revealing the potential engineering applications of polymeric gels.

Effect of impeller rotational phase on the FDA blood pump velocity fields.

The Food and Drug Administration (FDA) blood pump is an open-source benchmark cardiovascular device introduced for validating computational and experimental performance analysis tools. The time-resolved velocity field for the whole impeller has not been established, as is undertaken in this particle image velocimetry (PIV) study. The level of instantaneous velocity fluctuations is important, to assess the flow-induced rotor vibrations which may contribute to the total blood damage. To document these factors, time-resolved two-dimensional PIV experiments were performed that were precisely phase-locked with the impeller rotation angle. The velocity fields in the impeller and in the volute conformed with the previous single blade passage experiments of literature. Depending on the impeller orientation, present experiments showed that volute outlet nozzle flow can fluctuate up to 34% during impeller rotation, with a maximum standard experimental uncertainty of 2.2%. Likewise, the flow fields in each impeller passage also altered in average 33.5%. Considerably different vortex patterns were observed for different blade passages, with the largest vortical structures reaching an average core radii of 7 mm. The constant volute area employed in the FDA pump design contributes to the observed velocity imbalance, as illustrated in our velocity measurements. By introducing the impeller orientation parameter for the nozzle flow, this study considers the possible uncertainties influencing pump flow. Expanding the available literature data, analysis of inter-blade relative velocity fields is provided here for the first-time to the best of our knowledge. Consequently, our research fills a critical knowledge gap in the understanding of the flow dynamics of an important benchmark cardiovascular device. This study prompts the need for improved hydrodynamic designs and optimized devices to be used as benchmark test devices, to build more confidence and safety in future ventricular assist device performance assessment studies.

Experimental analysis and modeling of gas turbine engine performance: Design point and off-design insights through system of equations solutions

In this article, a systematic approach is presented for simulating turbojet engine performance at both design and off-design points. The construction of gas turbine engines involves a core, with additional components added based on the proposed methodology. Accurate formulation of component characteristics and their matching forms the basis for the system of equations needed for solving off-design engine performance. The developed algorithm's initial step involves comparing results with experimental data obtained from 230 N engines. Experimental testing utilizes a 780 N engine under diverse operating conditions, allowing determination of thrust values, fuel consumption, and outlet gas temperatures. An engine characteristic curve is derived under static conditions at ground level and validated against ground test results in Tehran. Unknown parameters are calibrated using a dedicated model, enabling the extraction of engine performance parameters across different corrected speeds. These results are then compared with GasTurb outputs. Comparative analysis between the proposed model's simulation and experimental data demonstrates high accuracy, affirming the reliability of the presented model.

Enhanced Medical Image Segmentation using Transfer Learning with Res101_UNet: Experimental Insights and Comparative Performance Analysis

Throughout the past few decades, artificial intelligence and machine learning have seen a lot of active research in areas such as computer vision, natural language processing, and speech processing. As a result, deep learning models became state-of-the-art for computer vision tasks such as object detection, classification, segmentation, and other allied tasks. Of course, the fruits of this research are extended to the design of robust and reliable digital health systems as well as other applications in the healthcare sector. Many clinical applications require the automatic segmentation of medical images. Recent deep learning-based approaches have demonstrated state-of-the-art performance in medical image segmentation tasks. In addition to their ability to automatically extract features and generalize over large amounts of data, transfer learning based deep learning models have proven to be handy for data scared areas like medical domains. In this research, we investigate and demonstrate the efficacy of a DCNN-based transfer learning model -Res101_Unet, which has been trained and/or fine-tuned to execute tumor tissue segmentation tasks in MRI, CT, PET, and X-RAY pictures of medical organ scans with little data. For our experimental study, we employed two image datasets: 'Liver Tumor' and 'Gland Colon Cancer', both obtained from the Kaggle portal. This experimental setup includes an Open-Source segmentation model API. Our findings indicate that domain similarity-based transfer learning can be used to data-scarce sectors. We achieved 98.47% accuracy and a IoU score of 0.9891 on Liver Tumor data and 0.6956 accuracy and a IoU score of 0.7043 on gland colon dataset.

Experimental evaluation of a multi-installment scheduling strategy based on divisible load paradigm for SAR image reconstruction on a distributed computing infrastructure

Radar loads, especially Synthetic Aperture Radar (SAR) image reconstruction loads use a large volume of data collected from satellites to create a high-resolution image of the earth. To design near-real-time applications that utilise SAR data, speeding up the image reconstruction algorithm is imperative. This can be achieved by deploying a set of distributed computing infrastructures connected through a network. Scheduling such complex and large divisible loads on a distributed platform can be designed using the Divisible Load Theory (DLT) framework. We performed distributed SAR image reconstruction experiments using the SLURM library on a cloud virtual machine network using two scheduling strategies, namely the Multi-Installment Scheduling with Result Retrieval (MIS-RR) strategy and the traditional EQual-partitioning Strategy (EQS). The DLT model proposed in the MIS-RR strategy is incorporated to make the load divisible. Based on the experimental results and performance analysis carried out using different pixel lengths, pulse set sizes, and the number of virtual machines, we observe that the time performance of MIS-RR is much superior to that of EQS. Hence the MIS-RR strategy is of practical significance in reducing the overall processing time, and cost, and in improving the utilisation of the compute infrastructure. Furthermore, we note that the DLT-based theoretical analysis of MIS-RR coincides well with the experimental data, demonstrating the relevance of DLT in the real world.

Experimental and simulative analysis of flexural performance in UHPC-RC hybrid beams

With high strength, excellent durability, and cracking resistance, ultra-high-performance concrete (UHPC) has gradually become popular. In this study, a novel hybrid beam was designed to fully harness the cracking resistance and tensile strength of UHPC. A series of experiments were conducted to investigate the influence of UHPC layer depth and steel bar diameter on the flexural performance of UHPC-RC hybrid beams. The experimental results indicated that the use of UHPC in the tensile zone of UHPC-RC hybrid beams can significantly improve the bearing capacity, crack resistance, and ductility of the structure. Based on the application of cohesive zone model (CZM), a finite-element (FE) model was proposed to simulate the mechanical behavior of the UHPC-RC hybrid beams, and the cohesive elements were used to represent the potential fracture surfaces of UHPC (concrete) and the rebar-concrete interface. A constitutive model for potential fracture of UHPC, taking into account the bridging effect of fibers, has been proposed. This FE model can reflect the fracture behavior of UHPC-RC hybrid beams. The simulation results demonstrate that the proposed model can accurately simulates the mechanical response and fracture behavior during the whole fracture process. Based on the results obtained from the experiment and simulation, a theoretical method for predicting the bearing capacity of UHPC-RC hybrid beams was developed, which can provide the reference for the design of similar structures.

Design of a mining carbon monoxide sensor and analysis of multi-gas cross-interference performance

Abstract A new type of carbon monoxide sensor is designed to address the issue of cross interference of nitrogen oxide gas in the exhaust emissions of underground diesel engine rubber-tired vehicles with electrochemical carbon monoxide sensors, which leads to frequent false alarm accidents. The hardware circuit design of the DC-DC voltage reduction power supply circuit, display circuit, component signal processing circuit, etc. is detailed, At the same time, the sensitive components used in the sensor adopt a special gas filtration membrane design. Six types of gases, including hydrogen sulfide, nitric oxide, nitrogen dioxide, hydrogen, ethylene, and acetylene, were sequentially introduced in the laboratory for experimental analysis of multi-gas cross-interference performance. The experimental results have shown that the new carbon monoxide sensor can filter out nitrogen oxide gas, thereby solving the impact of underground rubber tire vehicle exhaust on the accuracy of carbon monoxide gas detection. It has broad prospects for promotion and application in coal mines underground.

Experimental and numerical analysis of seismic performance of jacket platforms subjected to onshore and offshore earthquakes

Offshore platforms located in seismically active areas may be subjected to different seismic effects during service. The seismic performance of offshore platforms under different earthquakes was studied using shaking table tests and finite element analysis (FEA). The dynamic properties, acceleration, displacement and strain responses of the scale model under near-field, far-field and offshore earthquakes were studied. On this basis, more consideration was given to soil-pile-structure interactions (SPSIs), and this finite element (FE) model was analyzed for seismic fragility using incremental dynamic analysis (IDA). By combining the results of the tests and FEA, it was found that the dynamic response of the platform was significantly larger under offshore earthquakes than under onshore earthquakes. The collapse resistance of offshore platform under offshore earthquakes was inferior to that under onshore earthquakes. Therefore, seismic performance assessment of long-period offshore platforms based on onshore earthquakes may overestimate its seismic capacity and pose potential risks to platforms in service.

Experimental performance analysis of an infrared heating system for continuous applications of drying

One feasible approach for enhancing material quality and expediting the dehydrating procedure is using infrared radiation to provide heat. The impact of infrared power (0.130–0.341 W/cm2), airflow (0.5–1.5 m/s), and slice thickness (2–6 mm) on mass transfer, drying kinetics, colour, shrinkage, and rehydration ratio conditions. During the process, the dried samples' initial moisture content of 86.7 % was decreased to 11 % (w.b.). Eleven statistical factors were used to compare eleven alternative mathematical models. The results of regression analysis indicated that the Midilli et al. model best describes the drying behaviour in both techniques. The outcomes exhibited that the drying period rose at airflow and thickness but decreased with intensity. While the shrinkage ratio increased and declined with air velocity, the rehydration ratio grew and dropped with increasing infrared radiation intensity and airflow. As the intensity and airflow increased, there was a noticeable increase in the overall colour difference between slices of fresh and dry apples. The outcomes of this investigation will offer a further understanding of the ideal drying settings to create apple slices for snacking or other culinary purposes.

Experimental measurement and molecular dynamics simulation analysis of thermal aging performance in composite solid propellants

As a complex mixed system, the aging mechanism of high-energy composite materials involves the aging of each component itself, interactions between components, and transformation of microstructural and thermodynamic properties. The study of a single component or performance parameter has great limitations for elaborating the cognitive complexity of aging processes, making it difficult to reveal the underlying principles of physicochemical property transformation. Thus, it can only be applied as an empirical summary. In view of this, this study comprehensively utilized numerical analysis and experimental detection to explore the evolution of micromolecular conformation and changes in macro aging performance from four aspects of composite systems, including binder aging, plasticizer migration, bond interface debonding, and mechanical property transformation. There was good consistency observed between molecular simulation and thermal aging experiments, indicating that there was basically no post curing process for HTPB propellants using TDI as the curing agent. In the early stage of aging, scission chain was the main process and, in the later stage of aging, oxidation crosslinking the main process. Oxidative crosslinking increased the mean square radius of gyration and glass transition temperature of the binder system, reduced the peak value of radial distribution function, and revealed the reason for the change of propellant hardness and CC and CO double bond content. However, chain degradation increased the number of polar groups, enhanced intermolecular polarity, reduced the solubility parameter, and increased the free volume fraction of the mixed system and the dioctyl sebacate diffusion coefficient. This resulted in an increase in the tangent value of the HTPB propellant loss angle from 0.43 to 0.44° and a decrease in the glass transition temperature from 203.3 to 202.0 K. The binding energy at the interfaces of AP/HTPB and Al/HTPB increased first and then decreased, which was consistent with SEM images of bonding interfaces. The joint effect of binding energy and mechanical properties of the binder system promoted the transformation of the stress-strain curve of aging propellant.

Experimental and numerical convective heat transfer performance analysis of a confined impinging round jet with triangular tabs under crossflow influence

In this study convective heat transfer performance of a confined impinging round jet with/without nozzle tabs under channel crossflow is investigated experimentally and numerically for a wall mounted heated module. Numerical investigations are carried out for different jet to crossflow velocity ratios (Vr) and compared to experimental data. Four different Vr values (5,6,8, and 10) are tested for single target plate distance to jet nozzle diameter ratio (H/D=8). ANSYS Fluent software is used for numerical simulations while infrared thermography is utilized for experimental investigations. Surface temperature values of the wall mounted module are obtained and presented along with complex flow structures obtained via numerical simulations. Results show that crossflow has decisive effect on temperature distribution on the component. By inserting triangular tabs to the nozzle exit, it is possible to further decrease the surface temperature of the module and minimize the crossflow caused jet deflection. The addition of triangular tabs resulted in a significant increase of up to 10% in the mean Nusselt number on the top surface of the module at Vr=10.

Experimental and numerical analysis of bending performance for a glass-epoxy composite with integrated sheet-shaped shape memory alloy actuator elements

Shape memory alloys (SMA) belong to the group of smart materials and show particularly a promising potential for an active functionalization of lightweight composite structures with respect to enabling smart structures. In this work, various manufacturing concepts for the integration of thin sheet-shaped SMA actuator elements in a thin glass-epoxy composite beam are experimentally and numerically studied with regard to its bending deformation performance realized by thermal induced shape memory effect of the SMA actuator element. For numerical modeling, the shape memory effect of the SMA on structural level, a three-dimensional thermomechanical constitutive material model is applied. In the experiments, the same deformation pattern of the composite beam was observed for all integration concepts investigated, with the degree of deformation showing strong differences both when the shape memory effect is activated and deactivated. The complex material behavior of the SMA actuator under bending deformation is modeled via the finite element method with sufficient accuracy including existing tension and compression loads.

Viable-feasibility of innovated combined condenser over traditional individual condenser heat pipe solar evacuated tube water heating system: a comparative-conclusive approach

Purpose This study aims to provide an alternative adoption to overcome the energy crisis and environmental effluence by comparative theoretical and trial testing analysis of an innovative combined condenser unit over traditional individual condenser unit water heating systems. Design/methodology/approach The presented innovative new unit of the combined condenser heat pipe works efficiently through its improved idea and unique design, providing uniform heating to improve the heat transfer and, finally, the temperature of water increases without enhancing the cost. In this design, all these five evaporator units were connected with a single combined condenser unit in such a manner that after the condensation of heat transfer fluid vapour, it goes equally into the evaporator pipe. Findings The maximum temperature of hot water obtained from the combined condenser heating system was 60.6, 55.5 and 50.3°C at a water flow rate of 0.001, 0.002 and 0.003 kg/s, respectively. The first and second law thermodynamic efficiency of the combined condenser heating system were 55.4%, 60.5% and 89.0% and 2.6%, 3.7% and 4.1% at 0.001, 0.002 and 0.003 kg/s of water flow rates, respectively. The combined condenser heat pipe solar evacuated tube heating system promoting progressive performance is considered efficient and environment-friendly compared to the traditional condenser unit water heating system. Originality/value Innovative combined condenser heat pipe evacuated tube collector assembly was designed and developed for the study. A comparative theoretical and experimental energy-exergy performance analysis was performed of innovated collective condenser and traditional individual condenser heat pipe water heating system at various mass flow rate.

Drive–response asymptotic shape synchronization for a class of two-dimensional chaotic systems and its application in image encryption

This paper proposes the concept of drive–response asymptotic shape synchronization for two-dimensional chaotic systems and its application in image encryption. It overcomes the limitations of traditional shape synchronization, eliminates the restrictions on the drive system’s continuous differentiability, and the response system’s specific format, while simplifying the controller design, thereby demonstrating enhanced applicability and ease of implementation. Moreover, based on the characteristics of asymptotic shape synchronization, we propose a novel image encryption scheme. In this scheme, the drive and response systems, initialized with distinct values, achieve identical chaotic attractors through rotation and translation parameters in rigid transformation, which are utilized for encryption and decryption processes, respectively. Our encryption algorithm employs DNA coding to construct a DNA plane and incorporates the concept of Rubik’s cube rotations for scrambling and diffusion. Experimental simulations and performance analysis verify the effectiveness of the proposed encryption scheme in withstanding various attacks, ensuring a high level of security.

Effect of variable amplitude superimposed wave on piezoelectric actuator performance and experimental performance analysis

In order to bridge the gap between the effects of superposition of unequal amplitude waves on superimposed waves, this paper investigates the effects of variable amplitude superimposed waves on piezoelectric actuators. The generation mechanism of traveling waves is explored from the principle of superposition of waves. A mathematical model of the piezoelectric beam is established based on the Euler-Bernoulli beam theory and the Lagrange equation. It is the first time that the effects of variable amplitude superimposed waves on motion performance are investigated from both theoretical and experimental perspectives. The effects of variable amplitude waves on kinematic performance are tested by changing different excitation frequencies, different positions and different loadings. The relationship between the amplitude ratio A and the motion performance is given. It is shown that there is an approximately linear negative correlation between the amplitude ratio and the motion performance when the amplitude ratio A = 1–2.4. This study provides a new idea for the generation of traveling waves and provides a reference for the design and application of piezoelectric actuators.

Experimental investigation, performance analysis, and optimization of hot air convective drying of date fruits via response surface methodology

A laboratory-scale hot air convective dryer (HACD) was used to dry date fruits surplus at 0.5 ± 0.02 kg kg−1 to a safe moisture level of 0.35 kg kg−1 under drying temperatures (T) of 50–70 °C with airflow rates (Q) of 0.18 and 0.28 m3 h−1. Kinetics, modeling, energy, economic feasibility, and color difference of the date fruits were analyzed and then optimized using response surface methodology (RSM) with two drying factors and eight responses. The drying time to reach the desired moisture level ranged from 9 to 28 h under different drying conditions. The proposed mathematical model expressed the moisture behavior over drying time with the highest R2 = 0.9998 and 0.9999, respectively, for 0.18 and 0.28 m3 h−1. Effective moisture diffusivity (Deff) was calculated using the starting accessibility parameter and varied between 9.9 × 10−8 and 3.3 × 10−7 m2 s−1. The energy analysis revealed that the specific energy consumption (SEC) varies between 22.04 and 43.05 kWh.kg−1 and the drying efficiency (η) are 16.91, 16.14, and 25.38% for 50, 60, and 70 °C, respectively. The RSM optimization using a multi-level design with two centurium points denoted the optimum responses for the highest drying temperature. The lowest payback period (Pb) of the drying system was estimated to be 0.45 years for T = 70 °C and Q = 0.28 m3 h−1. The optimum drying time, Deff, total energy consumption (Et), SEC, η, and total color change (ΔE) were estimated to be 9 h, 3.3 × 10−7 m2 s−1, 33.91 kWh, 22.04 kWh.kg−1, 27.69%, and 1.69, respectively.

Image encryption scheme based on improved four-dimensional chaotic system and evolutionary operators

To enhance the security of image data transmission, and address the weaknesses of existing image encryption schemes based on chaotic systems, particularly concerning resistance to differential attacks and the unstable performance of chaotic systems, this article introduces an improved four-dimensional chaotic system and integrates evolutionary operators to propose an image encryption scheme. Firstly, a method for generating pseudo-random sequences associated with the plaintext is designed. The change rate of the ciphertext pixel value exceeds 0.9967 after a slight modification of the plaintext pixel value, significantly improving the plaintext sensitivity and the scheme's ability to resist selected plaintext attacks. Secondly, an individual rearrangement operation is introduced to achieve bit-level scrambling, and pixel-level scrambling is achieved by selection strategy. Subsequently, crossover and mutation operations are incorporated into image encryption. To reflect the randomness of the pairing, we adopt the pseudo-random sequence generated by the chaotic system to control the crossover and mutation operators, and a diffusion operation is performed on selected pixel pairs. Finally, ciphertext feedback is applied. Experimental results and performance analysis demonstrate that the proposed scheme not only enhances the security of encrypted images but also effectively resists noise and cropping attacks. This method effectively meets the high-security requirements of images in network transmission and provides new ideas for further research in the field of image encryption.

Solar drying of oregano leaves (Plectranthus amboinicus, Lour): Analysis of experimental performance under a tropical climate

Despite the multiple applications of the oregano ( Plectranthus amboinicus (Lour)), an important herbaceous plant because of its medicinal and culinary properties, limited research has been conducted on this species’ solar drying. Thus, the experimental drying of oregano leaves in a tropical climate was performed using direct and indirect solar drying and an electric oven in this research work. Also, mathematical modeling of the drying process, moisture diffusivity, activation energy, and colorimetric analysis (as a quality parameter) were accomplished to complement the experimental evaluation and understand the drying process behavior. The results show a shorter drying time obtained with the electric oven with 210 min reached at 65°C; however, the minimum solar drying time (250 min) was achieved with a maximum drying rate of 0.025 g water/g dry matter per minute and minimum final moisture between 0.28 and 0.13 g water/g dry matter was obtained with indirect solar dryer. Moreover, the models that better represented the experimental data were Modified Page, Page, and Logarithmic, with a maximum value of R2 obtained of 0.9980 corresponding to the Logarithmic model. Furthermore, a maximum effective diffusivity value of 1.81E-9 was obtained with direct solar dryer natural convection, while for the electric oven, were 1.14E-10, 2.280E-10, and 1.026E-09 for 45, 55, and 65°C, respectively. The activation energy for water diffusion in oregano leaves was 55.66 and 97.78 kJ/g mol for solar dryers and electric ovens, respectively, which were values very close to those reported in the literature. Finally, the colorimetric analysis exhibited a minimum color change value of 17.1 obtained for the indirect solar dryer, allowing better oregano preservation and maintaining its quality for the market, which makes it ideal for drying oregano in tropical climates and promotes solar drying use for sustainable growth of the region.

Potential of Steam Generating by The PMMA Fresnel Lens Concentrator for Indoor Solar Cooker Application

Solar power is an alternative energy source that can be used for cooking. It is a simple, secure, and useful way to cook food without using conventional fuels that pollute the air. Solar cookers offer various benefits to the user’s health, productivity, and income as well as to the environment. Solar energy is abundant in a tropical country like Indonesia, making it a dependable and sustainable of energy resource. The study’s goal is to analyze the potency of steam produced by a solar cooker that uses a Fresnel lens concentrator. The thermal performance of the Fresnel lens concentrator with a conical receiver on the solar cooker prototype is discussed in this research. In the construction of solar cookers, PMMA (Polymethyl-Methacrylate) Fresnel lenses, manual trackers, and conical receiver types are used. The research conducts an experimental analysis of the thermal performance of the prototype solar cooker using a Fresnel lens concentrator with a conical receiver. This empirical approach provides valuable data on the efficiency and effectiveness of the solar cooker design. The experiment result shows the cumulative average solar irradiation, the average collection of solar energy per time of Fresnel lens concentrator, and the heat utilized of steam from conical receiver are 709.09 W/m², 456.14 Watt, and 383.88 Watt, respectively. The results of this study suggest that Fresnel lens concentrators are a promising development for indoor solar cookers and therefore provide a pathway for increased utilization of solar cooking technology.