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35 pages, 9457 KiB

Open AccessArticle

Modelling and Optimisation of Hysteresis and Sensitivity of Multicomponent Flexible Sensing Materials

by Kai Chen, Qiang Gao, Yijin Ouyang, Jianyong Lei, Shuge Li, Songxiying He and Guotian He

Appl. Sci. 2025, 15(6), 3271; https://doi.org/10.3390/app15063271 - 17 Mar 2025

Viewed by 393

Abstract

The development of high-performance polymeric sensing materials is urgently needed for the development of force sensors. Hysteresis and sensitivity are considered to be one of the two key metrics for evaluating the performance of force sensors, and their performance-influencing factors and optimisation models [...] Read more.

The development of high-performance polymeric sensing materials is urgently needed for the development of force sensors. Hysteresis and sensitivity are considered to be one of the two key metrics for evaluating the performance of force sensors, and their performance-influencing factors and optimisation models have not been addressed. In this paper, a new Kepler optimisation algorithm (HKOA) and a long short-term memory network optimisation model (HKOA-LSTM) based on HKOA are proposed, and analytical models of the hysteresis and sensitivity are derived, respectively. First, multifactor experiments were conducted to obtain experimental data for the prediction models; the prediction models for the hysteresis and sensitivity performance of sensing materials were constructed using response surface methodology (RSM), Random Forest (RF), long short-term memory (LSTM) network, and HKOA-LSTM. Next, the four prediction models were evaluated; the comparison results show that the HKOA-LSTM model performs the best. Finally, the optimal solution of the prediction model is obtained using the multi-objective RIME (MORIME) algorithm. The findings indicate a hysteresis of 3.279% and an average sensitivity of 0.046 kPa⁻¹ across a broad pressure range of 0–30 kPa when the Fe₃O₄ content is 0.665 g, the carbon nanotube (CNT) content is 1.098 g, the multilayer graphene (MLG) content is 0.99 g, and the moulding temperature (MT) is 67 °C. The simulation outcomes for the hysteresis and sensitivity closely align with the experimental test values, exhibiting relative errors of 0.765% and 0.434%, respectively. Furthermore, the sensing performance in this study shows a significant enhancement compared to prior research, with the hysteresis performance improved by 31% and sensitivity increased by 26%. This approach enhances the experimental efficiency and reduces costs. It also offers a novel strategy for the large-scale, rapid fabrication of high-performance flexible pressure sensor materials. Full article

(This article belongs to the Special Issue Applied Electronics and Functional Materials)

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32 pages, 12116 KiB

Open AccessArticle

Design and Calibration of a Sensory System of an Adaptive Gripper

by Cezar Frincu, Ioan Stroe, Sorin Vlase and Ionel Staretu

Appl. Sci. 2025, 15(6), 3098; https://doi.org/10.3390/app15063098 - 12 Mar 2025

Viewed by 591

Abstract

The design and calibration of an adaptive gripper’s sensor system are presented in this research. Including the final constructive variants, the variants of the planned force sensor and slip sensors are detailed, highlighting their primary functional and constructive features. The key elements regarding [...] Read more.

The design and calibration of an adaptive gripper’s sensor system are presented in this research. Including the final constructive variants, the variants of the planned force sensor and slip sensors are detailed, highlighting their primary functional and constructive features. The key elements regarding the calibration of the force and slip sensors on each gripper module of the adaptive gripper are then displayed. Each sensor must be examined and calibrated independently due to its construction particularities. The important force and slip sensor behavior graphs are displayed, along with the calibration needed to ensure the adaptive gripper operates as intended. This paper suggestively shows, among the few papers of this kind, for the first time, the laborious but absolutely necessary process of calibrating force and slip sensors for gripping in general, and for adaptive gripping in particular. Full article

(This article belongs to the Special Issue Applied Electronics and Functional Materials)

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16 pages, 2865 KiB

Open AccessArticle

The Influence of Air Flow Rates and Voltage on the Plasma Emission Spectra and the Concentrations of Nitrogen Oxides Produced by Gliding Arc Discharge Plasma

by Liutauras Marcinauskas, Rolandas Uscila and Mindaugas Aikas

Appl. Sci. 2025, 15(1), 446; https://doi.org/10.3390/app15010446 - 6 Jan 2025

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Abstract

In this work, gliding arc discharge (GAD) was used to produce air plasma and investigate the influence of the discharge parameters on the composition of the air plasma, vibrational temperatures, and the production of NO_x. It was demonstrated that the main [...] Read more.

In this work, gliding arc discharge (GAD) was used to produce air plasma and investigate the influence of the discharge parameters on the composition of the air plasma, vibrational temperatures, and the production of NO_x. It was demonstrated that the main particles obtained in the GAD air plasma were N₂*, N₂⁺, N⁺, NO_γ, and O. It was observed that the reduction in the discharge frequency increased the intensity of the excited nitrogen molecules lines and reduced the nitric oxide (NO) and nitrogen dioxide (NO₂) gas concentrations. The increase in the output voltage prolonged the duration of arc discharge and enhanced the intensities of the emission lines of the N₂⁺, O, and NO_γ species and the concentrations of NO and NO₂ gasses. It was shown that the increase in the air flow rate from 6.7 L/min to 15.6 L/min decreased the concentration of the produced NO gas by 24%. Additionally, the line intensities of all main species in air plasma were enhanced. Studies have shown that the NO and NO₂ gas concentrations (selectivity of NO and NO₂) can be controlled by varying the air flow, output voltage, and discharge frequency. The highest NO_x concentration of 2380 ppm was produced at 250 V, when the direct air flow was 11.2 L/min. Full article

(This article belongs to the Special Issue Applied Electronics and Functional Materials)

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15 pages, 5038 KiB

Open AccessArticle

Investigation of the Automatic Monitoring System of a Solar Power Plant with Flexible PV Modules

by Žydrūnas Kavaliauskas, Igor Šajev, Giedrius Blažiūnas and Giedrius Gecevičius

Appl. Sci. 2024, 14(20), 9500; https://doi.org/10.3390/app14209500 - 17 Oct 2024

Cited by 1 | Viewed by 1376

Abstract

During this research, an automatic monitoring system was developed to monitor the working parameters in a solar power plant consisting of two flexible silicon modules. The first stage of the monitoring system relies on a microcontroller, which collects data from wattmeter modules made [...] Read more.

During this research, an automatic monitoring system was developed to monitor the working parameters in a solar power plant consisting of two flexible silicon modules. The first stage of the monitoring system relies on a microcontroller, which collects data from wattmeter modules made using a microcontroller. This tier also includes DC/DC converter and RS232-TCP converter modules for data transfer. The second stage, the industrial PLC, receives data from the first stage and transmits them to the PC, where the information is stored and the processes are visualized on the HMI screen. During this study, the charging process was analyzed using PWM- and MPPT-type charging controllers, as well as the power supply of Fito LED strips for lighting plants. Using the created monitoring system, the parameters of the solar power plant with flexible PV modules were monitored. This study compared PWM and MPPT battery charging methods, finding that MPPT is more efficient, especially under unstable solar conditions. MPPT technology optimizes energy usage more efficiently, resulting in faster battery charging compared to PWM technology. Full article

(This article belongs to the Special Issue Applied Electronics and Functional Materials)

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15 pages, 4148 KiB

Open AccessArticle

Development and Investigation of a Smart Impact Detector for Monitoring the Shipment Transport Process

by Žydrūnas Kavaliauskas, Igor Šajev, Giedrius Blažiūnas, Giedrius Gecevičius and Saulius Kazlauskas

Appl. Sci. 2024, 14(16), 7102; https://doi.org/10.3390/app14167102 - 13 Aug 2024

Cited by 3 | Viewed by 1304

Abstract

This study introduces an innovative smart impact detection system designed for real-time monitoring of shipment status and path integrity. Leveraging the advanced capabilities of the ESPRESSIF ESP32-S3-MINI-1U-N8 microcontroller, which integrates Wi-Fi, a display, a memory card slot, and accelerometers, this detector represents a [...] Read more.

This study introduces an innovative smart impact detection system designed for real-time monitoring of shipment status and path integrity. Leveraging the advanced capabilities of the ESPRESSIF ESP32-S3-MINI-1U-N8 microcontroller, which integrates Wi-Fi, a display, a memory card slot, and accelerometers, this detector represents a significant advancement in shipment tracking technology. The device is engineered to continuously measure impact magnitudes in terms of g-force, and records data when predefined impact thresholds are exceeded. These data are then wirelessly transmitted to a remote server, providing users with the ability to track shipment status and path via a dedicated application. The performance testing revealed impact measurements ranging from −0.5 to 2 g, with occasional peaks reaching approximately 4.5 g, demonstrating the system’s sensitivity and reliability in diverse conditions. This smart impact detector not only facilitates continuous monitoring, but also enhances the ability to respond swiftly to potential shipment violations, thus providing a novel solution for ensuring shipment integrity. This research contributes to the field by presenting a comprehensive real-time impact detection system that integrates modern microcontroller technology with effective monitoring capabilities, setting a new benchmark for shipment tracking systems. Full article

(This article belongs to the Special Issue Applied Electronics and Functional Materials)

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14 pages, 2933 KiB

Open AccessArticle

Investigation of an LED Strip Controller Based on a PWM Driver and a PIC Series Microcontroller

by Žydrūnas Kavaliauskas, Igor Šajev, Giedrius Blažiūnas, Giedrius Gecevičius and Aleksandras Iljinas

Appl. Sci. 2024, 14(10), 4110; https://doi.org/10.3390/app14104110 - 12 May 2024

Cited by 1 | Viewed by 1916

Abstract

This research paper investigates an LED strip lighting system, whose LED lighting controller was developed based on the PIC24FV32KA302 microcontroller and PCA9685 PWM driver. During the study, various parameters of the system were evaluated, including the response time from the length of commands, [...] Read more.

This research paper investigates an LED strip lighting system, whose LED lighting controller was developed based on the PIC24FV32KA302 microcontroller and PCA9685 PWM driver. During the study, various parameters of the system were evaluated, including the response time from the length of commands, the dependence of the PWM signal characteristics on the logic values generated by the microcontroller, and the dependence of the LED light flux and power on the percentage of the PWM signal and the power of the power supply channels. The results of the study revealed that the reaction time depended on the length of the sent command, where as the logic values of the microcontroller were changed from 1000 to 4000, the size of the PWM signal changed from 25 to 100%. The use of the I2C communication protocol, which is a master–slave architecture and uses data and synchronization lines, was also found to affect response times. When the percentage of the PWM signal was changed from 10 to 100%, the light flux of the LED strip changed from 100 to 1000 lm. These results reflect the advantages of applying microcontrollers and PWM drivers to LED control systems, emphasizing their flexibility, efficiency, and precise light control. Full article

(This article belongs to the Special Issue Applied Electronics and Functional Materials)

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Review

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28 pages, 3977 KiB

Open AccessReview

Influence of Polystyrene Molecular Weight on Semiconductor Crystallization, Morphology, and Mobility

by Zhengran He, Sheng Bi, Kyeiwaa Asare-Yeboah and Jihua Chen

Appl. Sci. 2025, 15(3), 1232; https://doi.org/10.3390/app15031232 - 25 Jan 2025

Viewed by 785

Abstract

The morphological characteristics of organic semiconductors significantly impact their performance in many applications of organic electronics. A list of challenges such as dendritic crystal formation, thermal cracks, grain boundaries, and mobility variations must be addressed to optimize their efficiency and stability. This paper [...] Read more.

The morphological characteristics of organic semiconductors significantly impact their performance in many applications of organic electronics. A list of challenges such as dendritic crystal formation, thermal cracks, grain boundaries, and mobility variations must be addressed to optimize their efficiency and stability. This paper provides an in-depth overview of how different polymer additives (conjugated, semicrystalline, and amorphous polymers) influence the crystallization, morphology and mobility of some well-studied organic semiconductors. Conjugated polymers enhance molecular alignment and crystallinity, leading to distinct crystalline structures and improved charge transport properties. Semicrystalline polymers offer in-situ crystallization control, which improves film morphology and increases crystallinity and mobility. Amorphous polymers help minimize misalignment and promote parallel orientation of organic crystals, which is critical for effective charge transport. Special attention is given to polystyrene (PS) as a representative additive in this review, which highlights the significant effects of its molecular weight (Mw) on film morphology and charge transport properties. In particular, low-Mw PS (less than 20k) typically results in smaller, more uniform crystals, and enhances both charge transport and interface quality. Medium-Mw PS (20k to 250k) balances film stability and crystallinity, with moderate improvements in both crystal size and mobility. High-Mw PS (greater than 250k) promotes larger crystalline domains, better long-range order, and more pronounced improvement in charge transport, although it may introduce challenges such as increased phase separation and reduced solubility. This comprehensive analysis underscores the decisive role of polymer additives in optimizing the morphology of organic semiconductors and maximizing their charge transport for next-generation organic electronic applications. Full article

(This article belongs to the Special Issue Applied Electronics and Functional Materials)

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18 pages, 3939 KiB

Open AccessReview

Towards Reliable ECG Analysis: Addressing Validation Gaps in the Electrocardiographic R-Peak Detection

by Syed Talha Abid Ali, Sebin Kim and Young-Joon Kim

Appl. Sci. 2024, 14(21), 10078; https://doi.org/10.3390/app142110078 - 4 Nov 2024

Viewed by 1743

Abstract

Electrocardiographic (ECG) R-peak detection is essential for every sensor-based cardiovascular health monitoring system. To validate R-peak detectors, comparing the predicted results with reference annotations is crucial. This comparison is typically performed using tools provided by the waveform database (WFDB) or custom methods. However, [...] Read more.

Electrocardiographic (ECG) R-peak detection is essential for every sensor-based cardiovascular health monitoring system. To validate R-peak detectors, comparing the predicted results with reference annotations is crucial. This comparison is typically performed using tools provided by the waveform database (WFDB) or custom methods. However, many studies fail to provide detailed information on the validation process. The literature also highlights inconsistencies in reporting window size, a crucial parameter used to compare predictions with expert annotations to distinguish false peaks from the true R-peak. Additionally, there is also a need for uniformity in reporting the total number of beats for individual or collective records of the widely used MIT-BIH arrhythmia database. Thus, we aim to review validation methods of various R-peak detection methodologies before their implementation in real time. This review discusses the impact of non-beat annotations when using a custom validation method, allowable window tolerance, the effects of window size deviations, and implications of varying numbers of beats and skipping segments on ECG testing, providing a comprehensive guide for researchers. Addressing these validation gaps is critical as they can significantly affect validatory outcomes. Finally, the conclusion section proposes a structured concept as a future approach, a guide to integrate WFDB R-peak validation tools for testing any QRS annotated ECG database. Overall, this review underscores the importance of complete transparency in reporting testing procedures, which prevents misleading assessments of R-peak detection algorithms and enables fair methodological comparison. Full article

(This article belongs to the Special Issue Applied Electronics and Functional Materials)

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