Radio Frequency Research Articles

Long-lived winter honey bees show unexpectedly high levels of flight activity compared to short-lived summer bees

In temperate regions, the overwintering success of honey bee colonies, Apis mellifera, depends on the last generations of long-lived bees emerging in autumn, known as winter bees. While the physiological qualities of winter bees and their extended lifespan are well documented, yet literature on their flight activity performance is scarce. Here we studied the flight activity of long-lived winter honey bees and compared their performance with short-lived bees. Using radio frequency identification (RFID), we automatically monitored the number of flights, the total flight duration and the lifespan of 523 honey bees that emerged over the course of a year, including short-lived bees from spring, summer and autumn, and long-lived winter bees. We found that flight activity performance of short-lived bees decreased progressively from spring to autumn for both the number of flights and the total flight duration. Furthermore, we confirm that only a fraction of the bees emerging before winter are long-lived winter bees, with a lifespan of 143.5 ± 23.5 days (mean ± SD). With an average of 37.5 ± 44.2 flights and 12.7 ± 15.5 h of flight, we found that long-lived winter bees were substantially more active than summer and autumn short-lived bees, but performed similar activity than spring short-lived bees. We also found that a small proportion of long-lived winter bees participate in the vast majority of the flight activity of the colony. Our results suggest that the extended lifespan of long-lived winter bees does not affect their flight activity performance, probably explained by their physiological qualities.

Apple Vision Pro-guided Laparoscopic Radio Frequency Ablation for Liver Tumors: The Pioneer Experience.

Background: This study evaluates the feasibility of Apple Vision Pro goggles as an augmented reality (AR) surgical navigation tool for laparoscopic-assisted ultrasound-guided radiofrequency ablation (RFA) of liver tumors. Traditional RFA is effective but challenging due to the integration of multiple imaging modalities.Purpose: The primary aim of this research is to assess how Vision Pro goggles can enhance the surgical navigation process during RFA, improving tumor localization and the overall effectiveness of the procedure.Research Design: A feasibility study design was used to analyze the implementation of AR technologies in surgical navigation, focusing specifically on their application in laparoscopic surgeries.Study Sample: Participants included patients undergoing laparoscopic-assisted ultrasound-guided RFA, with pre-operative imaging workups involving CT and MRI scans followed by intraoperative laparoscopic sonography.Data Collection and/or Analysis: Data were collected through observations during surgical procedures using the Vision Pro goggles, which displayed various imaging inputs (MRI, 3D reconstruction, and laparoscopic sonography) in the surgeon's field of view. Image manipulation was assessed based on accuracy and effectiveness of tumor ablation.Results: The goggles enhanced tumor localization accuracy and facilitated real-time image manipulation, resulting in effective tumor ablation. Initial results show promising outcomes in the precision and efficiency of the RFA procedure.Conclusions: While the initial results are promising, larger studies are necessary to validate the technology's efficacy and safety. Future research should compare outcomes with traditional methods and explore its applicability to other surgeries, aiming to refine the system further. The Vision Pro goggles potentially represent a significant advancement in surgical technology by improving RFA precision and efficiency.

Effect of Bi2O3 addition on the dielectric properties in radio frequency range of the BiCu3Ti3FeO12 matrix

Effect of Bi2O3 addition on the dielectric properties in radio frequency range of the BiCu3Ti3FeO12 matrix

Periodically poled aluminum scandium nitride bulk acoustic wave resonators and filters for communications in the 6G era

Bulk Acoustic Wave (BAW) filters find applications in radio frequency (RF) communication systems for Wi-Fi, 3G, 4G, and 5G networks. In the beyond-5G (potential 6G) era, high-frequency bands (>8 GHz) are expected to require resonators with high-quality factor (Q) and electromechanical coupling (kt2) to form filters with low insertion loss and high selectivity. However, both the Q and kt2 of resonator devices formed in traditional uniform polarization piezoelectric films of aluminum nitride (AlN) and aluminum scandium nitride (AlScN) decrease when scaled beyond 8 GHz. In this work, we utilized 4-layer AlScN periodically poled piezoelectric films (P3F) to construct high-frequency (~17–18 GHz) resonators and filters. The resonator performance is studied over a range of device geometries, with the best resonator achieving a kt2 of 11.8% and a Qp of 236.6 at the parallel resonance frequency (fp) of 17.9 GHz. These resulting figures-of-merit are (FoM1=kt2Qp and FoM2=fpFoM1×10−9) 27.9 and 500, respectively. These and the kt2 are significantly higher than previously reported AlN/AlScN-based resonators operating at similar frequencies. Fabricated 3-element and 6-element filters formed from these resonators demonstrated low insertion losses (IL) of 1.86 and 3.25 dB, and −3 dB bandwidths (BW) of 680 MHz (fractional BW of 3.9%) and 590 MHz (fractional BW of 3.3%) at a ~17.4 GHz center frequency. The 3-element and 6-element filters achieved excellent linearity with in-band input third-order intercept point (IIP3) values of +36 and +40 dBm, respectively, which are significantly higher than previously reported acoustic filters operating at similar frequencies.

A noise-robust post-processing pipeline for accelerated phase-cycled 23Na Multi-Quantum Coherences MRI.

To develop an improved post-processing pipeline for noise-robust accelerated phase-cycled Cartesian Single (SQ) and Triple Quantum (TQ) sodium (23Na) Magnetic Resonance Imaging (MRI) of in vivo human brain at 7 T. Our pipeline aims to tackle the challenges of 23Na Multi-Quantum Coherences (MQC) MRI including low Signal-to-Noise Ratio (SNR) and time-consuming Radiofrequency (RF) phase-cycling. Our method combines low-rank k-space denoising for SNR enhancement with Dynamic Mode Decomposition (DMD) to robustly separate SQ and TQ signal components. This separation is crucial for computing the TQ/SQ ratio, a key parameter of 23Na MQC MRI. We validated our pipeline in silico, in vitro and in vivo in healthy volunteers, comparing it with conventional denoising and Fourier transform (FT) methods. Additionally, we assessed its robustness through ablation experiments simulating a corrupted RF phase-cycle step. Our denoising algorithm doubled SNR compared to non-denoised images and enhanced SNR by up to 29% compared to Wavelet denoising. The low-rank approach produced high-quality images even at later echo times, allowing reduced signal averaging. DMD effectively separated the SQ and TQ signals, even with missing RF phase cycle steps, resulting in superior Structural Similarity (SSIM) of 0.89±0.024 and lower Root Mean Squared Error (RMSE) of 0.055±0.008 compared to conventional FT methods (SSIM=0.71±0.061, RMSE=0.144±0.036). This pipeline enabled high-quality 8x8x15mm3 in vivo 23Na MQC MRI, with a reduction in acquisition time from 48 to 10 min at 7 T. The proposed pipeline improves robustness in 23Na MQC MRI by exploiting low-rank properties to denoise signals and DMD to effectively separate SQ and TQ signals. This approach ensures high-quality MR images of both SQ and TQ components, even in accelerated and incomplete RF phase-cycling cases.

A Fully Printable Strain Sensor Enabling Highly-Sensitive Wireless Near-Field Interrogation.

Wireless, passive, and flexible strain sensors can transform structural health monitoring across various applications by eliminating the need for wired connections and active power sources. Such sensors offer the dual benefits of operational simplicity and high-function adaptability. Herein, a novel wireless sensor is fabricated using radio frequency (RF) technology for passive, wireless measurement of mechanical strains. Previously introduced concept of coupling piezoresistive electrodes is utilized with capacitive sensors to ensure high-sensitivity capacitive sensing. For the first time, it is implemented and demonstrated here as a fully printable, inexpensive, and ready-to-use device utilizing the recent advances in piezoresistive inks and screen-printing technologies. The near-field communication (NFC) tag features an inductor - capacitor (LC) resonant circuit with a distinct resonant frequency. The sensor exhibits high sensitivity and detects substantial variations in capacitance, with a gauge factor (GF) of ≈16 at 20 MHz for strain levels below 5%. Within the wireless framework, the sensor achieves a significant shift in resonance frequency (GF of ≈2.2). It also exhibited excellent performance in wirelessly monitoring the strain in a glass fiber-reinforced polymer (GFRP) specimen during the bending test. The results confirm the potential applicability of the sensor as an embedded sensor for monitoring various types of composite structures. This confirms the potential of the sensor for use in composite structures as an embedded sensor.

Assessing the effectiveness of the SOLIO Alfa Cure Plus device in treating low back pain: a randomized controlled study

BackgroundNonspecific low back pain (LBP) has become a significant worldwide public health problem. It is estimated that 84% of people present it at some point in their lives, in which 23% experience its chronic form, negatively affecting their daily lives. Because pain management tool that doesn’t require a firm diagnosis, the development of a device, as SOLIO Alfa Cure Plus, that emanates low level laser therapy, radio frequency and heat with the goal of easing chronic back pain was highly expected.Methodsrandomized, single blinded, controlled trial. Measures: Numeric Pain Rating Scale (NPRS), the Oswestry Disability Index (ODI) and the Schober’s test. Thirty-seven patients completed pain, disability, and lower back flexibility scales. Randomization was obtained by having an equal amount of sham and real devices and distributing them randomly to patients out of a box where the devices were.ResultsWe observed a larger pain relief in the SOLIO group (42% vs. 23% p = 0.03), and a higher improvement in flexibility (13%) compared to a worsening in the sham group (6.5%; p = 0.04).ConclusionWe concluded that utilizing the SOLIO Alfa Cure Plus device may dramatically reduce back pain and allow patients to experience an improvement in quality of life as a result. Trial registration: The clinical trials registration is 8475-21-SMC.

Frequency-Based Analysis of Matching Accuracy Between Satellite Radio Frequency and AIS Data for Ship Identification

Frequency-Based Analysis of Matching Accuracy Between Satellite Radio Frequency and AIS Data for Ship Identification

Impact of different drying techniques on Moringa oleifera leaves as a sustainable tea alternative

Tea is one of the most widely consumed beverages globally. Among the wide varieties, moringa-based tea is considered a nutritious drink and a traditional drink alternative, is rich in phytochemicals. By offering a nutritious, phytochemical-rich alternative like moringa tea, this study supports SDG 3 (Good Health and Well Being), ensuring healthier beverage options. This study uses three different drying techniques (hybrid solar drying, fluidized bed drying, and radio frequency (RF)) to dry the leaves and asses the nutritional profiles. Results say RF drying proved to be the most effective, and preserves the highest levels of essential nutrients than others. This aligns with SDG 12 (Responsible Consumption and Production), as RF drying promotes sustainable food processing by retaining essential nutrients in Moringa tea leaves. RF dried green tea curls exhibited the highest protein content (19.88%), crude fiber (9.96%), ash content (9.7%), Vitamin C (10.38 mg/100 g) and superior phenolic (52.23 mg GAE/g), and flavonoid contents (32.92 mg Catechin Eq/g), contributing to enhanced antioxidant capacity (70.02%). Color analysis indicated that RF drying produced darker tea leaves, especially in white and green teas, signifying more efficient moisture removal. The water activity was lowest in RF-dried black tea (0.35), suggesting improved preservation and shelf stability. The highest sensory score attained for black tea than others (white tea, green tea (both unfermented), oolong tea (semi-fermented)). These results underscore the advantages of RF drying in preserving the nutritional and sensory quality of moringa-based tea leaves, highlighting its potential as an optimal technique for tea processing.Graphical

Radiofrequency evoked potentials: A new window into the nociceptive system.

To describe the cortical evoked potentials in response to radiofrequency stimulation (RFEPs) in human volunteers. Seventeen healthy volunteers participated in an experimental session in which radiofrequency (RF) and electrical (ES) stimulation were applied to the dorsum of the hands and feet. EEG was recorded to evaluate evoked responses for each stimulus modality and stimulation site. Electrophysiological results showed highly synchronous responses compatible with activation of heat-sensitive nociceptors. Latencies of the N2 and P2 peaks in the RFEPs were longer compared to EPs evoked by ES. Furthermore, the latency of the P2 peak was also longer after stimulation of the feet compared to the hand. RF stimulation is capable of selective activation of nociceptive fibres by means of rapid skin heating. RFEPs showed the highest degree of synchronicity achieved to date for evoked cortical responses to thermal stimulation. RF stimulation represents a viable alternative in the experimental and clinical assessment of the nociceptive system.

Measuring the effect of RFID and marker recognition tags on cockroach (Blattodea: Blaberidae) behavior using AI-aided tracking.

Radio frequency identification (RFID) technology and marker recognition algorithms can offer an efficient and non-intrusive means of tracking animal positions. As such, they have become important tools for invertebrate behavioral research. Both approaches require fixing a tag or marker to the study organism, and so it is useful to quantify the effects such procedures have on behavior before proceeding with further research. However, frequently studies do not report doing such tests. Here, we demonstrate a time-efficient and accessible method for quantifying the impact of tagging on individual movement using open-source automated video tracking software. We tested the effect of RFID tags and tags suitable for marker recognition algorithms on the movement of Argentinian wood roaches (Blapicta dubia, Blattodea: Blaberidae) by filming tagged and untagged roaches in laboratory conditions. We employed DeepLabCut on the resultant videos to track cockroach movement and extract measures of behavioral traits. We found no statistically significant differences between RFID tagged and untagged groups in average speed over the trial period, the number of unique zones explored, and the number of discrete walks. However, groups that were tagged with labels for marker recognition had significantly higher values for all 3 metrics. We therefore support the use of RFID tags to monitor the behavior of B. dubia but note that the effect of using labels suitable for label recognition to identify individuals should be taken into consideration when measuring B.dubia behavior. We hope that this study can provide an accessible and viable roadmap for further work investigating the effects of tagging on insect behavior.

A new framework to assess the impact of new IT-based technologies on the success of quality management system

Today, the ever-increasing growth of technology and data has undeniably affected various industries. Due to the importance of the factor of comprehensive quality management (QM), big data, and information technology (IT) in the industry and the increasing attention to it, different attitudes regarding the ways and means of reaching it have been presented by these sources. As a result, the purpose of this research is to study new IT-based technologies related to the success of the QMS. The statistical population of this research is the managers and employees of the technology sectors, which is equal to 400 people. The sample size was equal to 196 people, and a simple random sampling method was used to obtain the sample size. This research is applied in terms of its nature and purpose, and in terms of the data collection method, it is a descriptive and survey type. PLS structural equation modeling and SPSS software were used for data analysis. The findings showed that the internet of things (IoT), business intelligence (BI), cloud computing, and distributed systems have a significant impact on the success of the QMS, while near-field communication and radio frequency identification have an impact on the success of the QMS through the intermediary variable of the IoT. Finally, the results revealed that the expert systems also affect the success of the QMS through the mediator variable of BI.

Observation of broadband super-absorption of electromagnetic waves through space-time symmetry breaking.

Using time as an additional design parameter in electromagnetism, photonics, and wave physics is attracting considerable research interest, motivated by the possibility to explore physical phenomena and engineering opportunities beyond the limits of time-invariant systems. Here, we report the experimental demonstration of enhanced broadband absorption of electromagnetic waves in a continuously modulated time-varying system, exceeding one of the key theoretical limits of linear time-invariant absorbers. This is achieved by harnessing the frequency-wave vector transitions and enhanced interference effects enabled by breaking both continuous space- and time-translation symmetries in a periodically time-modulated absorbing structure operating at radio frequencies. Furthermore, we demonstrate broadband coherent wave absorption using a secondary control wave, observing a nearly perfect, reconfigurable, antireflection effect over a broad continuous bandwidth. Our findings provide insights into enhanced wave absorption in time-varying scenarios and may enable the development of devices operating in a regime fundamentally beyond the reach of linear time-invariant systems.

Electromagnetic monitoring of the drying of in-shell Macadamia nuts

Macadamia nuts require drying to facilitate shelling, to improve the taste, and to extend shelf-life. In this research, the dielectric properties of whole nuts (kernel in shell) were measured using a coaxial resonator and an inexpensive vector network analyser, during the course of drying procedures. It was found that a collection of raw nuts had a real relative permittivity of 1.4 at low frequencies, which increased to 2.1 at 0.24 GHz, and an imaginary relative permittivity of 0.015 at low frequencies, rising to 0.10 at 0.24 GHz. With increased drying, both components decreased. The relative permittivity correlated with mass loss during drying. It is expected that the results can be used in designing a real-time drying monitor, and a radio frequency or microwave heating scheme for drying.

Neutral gas temperature of adamantane in a radio-frequency inductively coupled plasma electrothermal micro-thruster using optical emission spectroscopy

Abstract The gas temperature of adamantane plasma in a 13.56~MHz radio-frequency (RF) inductively coupled plasma was measured using optical emission spectroscopy. Rovibrational band fitting of the Second Positive System of nitrogen gas (N$_2$) from the addition of N$_2$ and Swan system of homo-nuclear carbons (C$_2$) from adamantane dissociation were used to obtain the gas temperature through the rotational temperature under the assumption of rotational-translational equilibrium. The measured temperature ranged from 400~K to 700~K, increasing with RF power range from 10~W to 100~W and adamantane flow rate from 0.25~mg~s$^{-1}$ to 1~mg~s$^{-1}$, with discharge pressures up to a few Torr. The energy released during adamantane dissociation contributed to a slight temperature increase compared to conventional pure N$_2$ plasma. Adding a large amount of helium (He) acted as a quencher, reducing the gas temperature. In an adamantane-He mixture, the gas temperature remained stable at mid-range power and at lower adamantane flow rates. Justification of gas temperature and a simple power balance model were described. Applications of adamantane spectroscopy include propulsion, plasma processing, and astrophysics, with the inclusion of future studies.

A CPW-Fed Hybrid Polarization-Frequency Reconfigurable Antenna with TCM Analysis for 5G New Radio Frequency Applications

A CPW-Fed Hybrid Polarization-Frequency Reconfigurable Antenna with TCM Analysis for 5G New Radio Frequency Applications

A self-powered wireless monitoring system driven by ambient RF energy for switch rails

Purpose This study aims to develop a novel self-powered monitoring system that uses radio frequency (RF) energy harvesting and ultra-low-power management technologies for real-time condition monitoring of switch rails. Design/methodology/approach The system is designed for integration within the jump wire holes of switch rails, ensuring structural integrity and aesthetic appeal. It features a highly efficient energy harvesting mechanism combined with optimized power management for wireless sensor nodes. An on-board antenna captures ambient RF energy, managed by high-efficiency circuits to ensure stable wireless sensor operation. An ultra-low-power system-on-chip is used to acquire and transmit multimodal data on vibration and temperature from the switch rails. The data collection is enhanced through a two-threshold approach, adapting to harvested energy levels for self-energy balancing. Findings Testing revealed that the energy harvesting subsystem operated stably at distances up to 2.9 m from the RF source, charging a 200 µF capacitor to 4.2 V in just 220 s. The monitoring subsystem’s average power consumption is in the low microwatt range. Continuous operation over 30 days in real conditions resulted in only a 5 mV reduction in battery voltage, indicating successful self-powered operation and validating long-term reliability in unattended scenarios. Originality/value This research presents an innovative solution, integrating RF energy harvesting with ultra-low-power technology, which addresses the power and stability challenges faced by traditional monitoring systems.

Near-Field Clutter Mitigation in Speckle Tracking Echocardiography.

Near-field (NF) clutter filters are critical for unveiling true myocardial structure and dynamics. Randomized singular value decomposition (rSVD) stands out for its proven computational efficiency and robustness. This study investigates the effect of rSVD-based NF clutter filtering on myocardial motion estimation. In silico, material points and their displacements in a homogeneous medium under uniaxial compressions (0.5% - 9% axial strains at 0.5% increments) were simulated in finite-element models. They were exported to the k-Wave toolbox for simulations of pre- and post-deformed ultrasound images with/ without a realistic phase aberrating layer in a high-contrast diverging wave compounding scheme. In vivo, echocardiograms of 20 normal human hearts were acquired using a coded diverging wave compounding imaging method at 3200 frames/second in the transthoracic apical four-chamber view. Morphological component analysis (MCA), which is also a sparse representation method but computationally intensive, was used for comparison with rSVD. Both rSVD- and MCA-based filters were applied to beamformed ultrasound radio-frequency (RF) data before cross-correlation-based speckle tracking. Contrast-to-noise ratios (CNRs) and root-mean-square deviations (RMSDs) were computed from regions of interest to evaluate NF clutter filtering performance of rSVD and MCA. In silico, 2-D displacements estimated from rSVD-based clutter-reduced image data showed strong agreement with ground truth (R2 of 0.95). In vivo, CNR improvements ranged from 1.02 dB to 17.68 dB, consistently enhancing image quality across all subjects. An improvement of ∼4.9 dB in the apical segments was observed in 80% of cases. Mean RMSDs were below 5.0% for all rSVD-based NF clutter-reduced data. While both rSVD and MCA effectively filtered NF clutter, rSVD was significantly more practical. Our findings confirm the reliability, accuracy, and efficiency of rSVD-based clutter filtering in speckle tracking echocardiography. This underscores the feasibility of matrix decomposition-based methods, exemplified by rSVD, in NF clutter filtering for myocardial motion estimation.

The Role of Fractional Radiofrequency in Long-term Acne Remission and Reduction of Acne Scar Load.

Acne is an inflammatory skin disease afflicting the majority of the world's population at some point in their lifetime, and is seen to be chronic in about 50% of cases. Acne leads to significant social withdrawal, depression, and disfiguring scars in many cases. Available treatments are characterized by high rates of relapse, dangerous side effects, and social stigma, which often leads to poor patient compliance and treatment failure. The aim of this article was to discuss and share the authors' experiences utilizing fractional radiofrequency (RF) (Morpheus8; InMode Ltd., Lake Forest, CA) in the treatment of both active acne and acne scars. A retrospective review was conducted comparing 3 treatment modalities. In total, 356 patients received acne scar treatments. The cohort comprised a high-dose isotretinoin topical therapy series (n = 128, 36%), a 6-session ablative laser series (n = 89, 25%), and a 3-session fractional RF microneedling series (n = 139, 44). Of the patients with extended 3-year follow-up, the relapse rates were: isotretinoin group, 36 of 54 (67%); laser group, 12 of 16 (75%), and fractional RF microneedling group, 7 of 29 (24%). In treating older acne scars, fractional RF microneedling technology has served as an effective tool to tighten skin and fill in atrophic scars when used in conjunction with other techniques. This technology is very effective and very safe for treating all skin types with acne and acne scars.

Analisa Sinyal Remote Control Untuk Aplikasi Pengendali Jarak Jauh

Indonesia's aerospace sector plays a crucial role in maintaining national sovereignty. However, the country's airspace is often infiltrated by irresponsible parties, necessitating an effective monitoring system. Unmanned radio-controlled helicopters are a potential solution, although they are limited in range. This study aims to design a long-range control system for radio-controlled helicopters using satellite phone communication, which offers wide coverage and can reach remote areas. The system comprises a remote control, a radio converter circuit, an audio mixer, and a satellite phone. The radio converter functions to transform the radio control signal frequency into its original frequency without a carrier frequency, which is then re-converted to be compatible with satellite phone input for signal transmission. Test results indicate that the system can transmit control signals with adequate frequency stability within the expected range. Despite minor oscillator instability at certain stages, the system overall operates as designed. In conclusion, this satellite phone-based control system effectively extends the operational range of radio-controlled helicopters and serves as a strategic solution for monitoring Indonesia's airspace.