Radio Frequency Processing Research Articles

Improving radio frequency heating uniformity in peanuts: Effects of packaging geometry, electrode gap, particle size and interlayer displacement process

This study aimed to assess the impact of various processing parameters including electrode gap, packaging geometry, and particle size on the heating efficiency of radio frequency (RF) processing for peanut thermal decontamination. In addition, interlayer displacements were presented to evaluate the effect of the mixing on heating uniformity.Experimental studies were carried out using 3D-printed polylactic acid (PLA) containers (square, rectangular, and cylindrical) to place the peanut samples with particle sizes ranging from 0.71 to 2.00 mm at 100–140 mm electrode gaps. Temperature changes within the samples were monitored using fiber optic sensors and surface temperature distributions were determined with an infrared camera. Heating uniformity index (λ) was then calculated to assess the effects of RF processing conditions on RF heating uniformity.Results showed that the cylindrical container exhibited a more consistent and uniform heating profile (λ = 0.12) with 1.58 °C min−1 heating rate compared to other containers, and a single interlayer displacement between top and bottom layers further improved temperature distribution uniformity. Smaller particle sizes also led to faster heating rates from 1.71 to 1.55 °C min−1 with more uniform heating due to the reduced porosity within the particles with increased thermal conduction and electromagnetic energy absorption. This study presented valuable insights for developing an effective RF process as an alternative to conventional thermal treatments for decontamination of low-moisture, high-fat particulate foods. Industrial significanceThis research presented an innovative approach applying RF heating for a possible decontamination process for peanut samples. The research tackled the growing worldwide consumer demand for food products to satisfy food safety regulations while peanuts were selected to demonstrate the process effect due to the recent food safety issues in peanut butter considering that a pre-process for decontamination would lead to a decrease in the resulting safety issues.

Radio frequency food processing. Current status and perspectives – a review

The present review provides a critical overview of the current status and prospects for the development and application of radio frequency food processing. The mechanism of action of radio frequency treatment, the dielectric properties of foods, the mechanisms for inactivating microorganisms and endogenous enzyme systems, the sensory and physicochemical changes occurring in radio frequency treated foods, as well as the application of radio frequency treatment in the food industry are discussed. Radio frequency processing technology has been found to have some advantages over conventional heat exchange systems in terms of time savings, higher profitability and better efficiency. In the available literature, the conducting of additional studies regarding the package violation and its permeability and integrity during radio frequency processing were discussed. Radio frequency heating has been shown to effectively eliminate pathogens and preserve better, physicochemical and sensory properties of food products compared to conventional heating due to shorter processing time. It is concluded that radio frequency energy heating is suitable for processing packaged foods that remain safe and stable during storage. For these reasons, it is concluded that radio frequency food processing has a very bright future.

Radio frequency inactivation of Salmonella Typhimurium and Listeria monocytogenes in skimmed and whole milk powder

Milk powder is a convenient, shelf-stable food ingredient used in a variety of food products. However, pathogenic bacteria can be present and survive during prolonged storage, leading to outbreaks of foodborne diseases and product recalls. Radio frequency (RF) heating is a processing technology suitable for bulk treatment of milk powder, aiming at microbial inactivation. This study investigates the RF inactivation of Salmonella Typhimurium and Listeria monocytogenes in two types of milk powder; skimmed and whole milk powder. Specifically, the aims were to (i) examine the influence of the powder's composition on bacterial inactivation, (ii) evaluate the response of bacteria with different Gram properties (Gram positive and Gram negative) and (iii) verify the use of Enterococcus faecium as a surrogate for the two microorganisms for the specific RF process. In order to examine exclusively the influence of RF, a non-isothermal temperature profile was used, employing solely different RF energy levels to heat the product to the target temperatures. A log-linear model with a Bigelow-type temperature dependency was fitted to the experimental data. S. Typhimurium was less susceptible to RF treatments in comparison to L.monocytogenes, demonstrating a higher inactivation rate (k) and higher percentage of sublethal injury. A higher k was also observed for both microorganisms in the whole milk powder, indicating that the increased fat content and decreased levels of lactose and protein in the milk powder had an adverse impact on the microbial survival for both pathogens. The surrogate microorganism E. faecium successfully validated the microbial response of the two microorganisms to RF treatments. In general, a low heating rate RF-only process was successful in inactivating the two foodborne pathogens in skimmed and whole milk powder by 4 log(CFU/g).

Optimizing Radiofrequency Exposure Parameters for One-Pass Drying of High-Moisture Paddy Rice

Highlights The utilization of standardized Radiofrequency (RF) exposure parameters ensures safety and process consistency. Equations were used to estimate Power Density (S), Specific Absorption Rate (SAR), and Electric Field Intensity (E). One-pass RF drying effectively lowered paddy rice (Cultivar [cv.] XL-753) initial Moisture Content (MC; 20.4% w.b.) to safe levels (=13.5% w.b.) with SARAdjusted of 1.87 × 106 J, E of 46.82 V/m, and S of 300,000 W/m² (6,000 W/kg). Higher SARAdjusted values impacted paddy rice surface lipid content and milling yields, while minor changes in color and viscosity showed inconsistent and subtle practical effects. Abstract. Radiofrequency (RF) heating utilizes high-frequency electromagnetic waves to induce heat within materials via molecular friction. This method offers rapid, even heating, deep penetration, and energy efficiency. Nevertheless, there is a dearth of research on RF exposure parameters concerning food processing. Investigating these parameters is crucial for RF process optimization, setting safety guidelines, and guaranteeing product quality. This research clarifies RF exposure parameters through the one-pass drying of high moisture content (MC) long-grain paddy rice (cultivar [cv.] XL-753) at an initial MC of 20.4% wet basis (w.b.) to a final of MC of = 13.5% w.b. (safe MC for storage). The specific objectives of this research were to: 1. Advocate the utilization of standardized RF exposure parameters (Specific Absorption Rate, SAR; Electric Field Intensity, E; and Power Density, S) of food and agricultural products, aiming to simplify RF processing, fostering consistency and safety in operations. 2. Estimate the RF exposure parameters associated with the one-pass RF drying process. 3. Determine the RF exposure parameters’ influence on rice physicochemical attributes of Milled Rice Yield (MRY), Head Rice Yield (HRY), Color Parameters (L* a* b*), Surface Lipid Content (SLC), and Pasting Properties. Using a pilot-scale parallel-plate RF heating system (6 kW, 27.12 MHz) with a 105 mm product-to-emitter gap, RF exposure parameters were determined: E = 46.82 V/m; EEff = 33.11 V/m; S = 300,000 W/m²; SAR = 2,224.95 W/kg. Rice samples underwent RF exposure durations of 360, 600, and 840 s, resulting in SARAdjusted levels of 0.80 × 106, 1.33 × 106, and 1.87 × 106 J, respectively. Half of the RF-processed paddy rice underwent tempering, which involved immediately transferring paddy rice after RF treatments into sealed glass jars and then into an incubator set to a constant temperature of 60°C for a duration of 4 h. RF processed samples at the highest SARAdjusted tested (1.87 × 106 J) followed by tempering resulted in MC reductions of 6.7% pt. w.b., final MC of 14.0% w.b., MRY, HRY, and SLC of 70.80%, 47.38%, and 0.47%, respectively. Non-tempered samples at the same SARAdjusted level had MC reductions of 7.34% pt. w.b., final MC of 13.1% w.b., MRY, HRY, and SLC of 60.91%, 4.53%, and 0.43%. Tempering and SARAdjusted values slightly affected rice physicochemical characteristics of color and viscosity. However, the differences were minor and inconsistent. To ensure optimal quality in large-scale RF drying of rice, it is crucial to avoid SARAdjusted levels exceeding 1.33 × 106 J. Exceeding this threshold has been shown to cause overheating, adversely impacting the grain’s quality. Moreover, implementing a tempering process post-drying is also essential in mitigating these detrimental effects. Keywords: Color, Electric field intensity (E), Lipids, Milling yields, Power density (S), Radio-frequency (RF), Rice drying, Specific absorption rate (SAR), Viscosity.

Radiofrequency Inactivation of Salmonella in Black Pepper and Dried Basil Leaves Using In-package Steaming

Radiofrequency (RF) heating has been extensively studied for pasteurizing low-moisture foods. Currently, bulk foods are treated with radiofrequency; potential cross-contamination may occur during packaging of pasteurized products. As an alternative, in-package RF processing was evaluated for Salmonella inactivation on black peppercorns and dried basil leaves and prevention of cross-contamination during storage postprocessing. In-package steaming refers to the process in which the samples were heated in a steam vent package to generate and retain steam during the treatment. This treatment achieved good heating uniformity which could be because of the circulation of steam within the package. One-way steam vent allowed the release of excess steam once a threshold pressure was achieved and later returned to its original position to seal the package, when the RF energy was removed. In-package RF steaming of black peppercorns and dried basil leaves for 135 s and 40 s, respectively, resulted in more than 5 log reduction of Salmonella. The steam vent remained stable posttreatment and properly sealed the package to protect the product from any external contamination. These results indicate that the use of steam vent could effectively pasteurize black peppercorns and dried basil leaves could be beneficial in preventing the potential cross-contamination postprocessing.

Effects of TiO2 thin films on silicon nanowire arrays in heterojunction solar cells

In recent years, the energy crisis has gained increasing attention, with greater emphasis being placed on renewable energy. Currently, solar power is regarded as the most developed form of renewable energy. Many materials have been used in solar cells. Radiofrequency (RF) magnetron sputtering is an effective technique used to produce large-area, easy-to-process thin films. In this study, we fabricated p-layer silicon nanowire (SiNW) arrays by using electroless etching to replace previous multilayer films. TiO2-SiNW array heterojunctions were fabricated by preparing TiO2 as an N layer through magnetron sputtering. Subsequently, the Grey–Taguchi method was used to analyze and optimize p–n heterojunctions with TiO2 films. After the effects of the sputtering parameters (RF power, process pressure, deposition temperature, and deposition time) on surface morphology, material structure, photoelectric conversion efficiency, and reflectivity were investigated, an aluminum-doped zinc oxide (AZO) window layer was added and annealed. Grey correlation analysis revealed a decrease in reflectivity from 8.02225 % to 7.72081 % and an increase in photoelectric conversion efficiency from 0.01915 % to 0.082 %. During the confirmation runs, the TiO2 film was found to be amorphous and wrapped around an array of SiNWs. After the AZO window layer was added, reflectivity increased to 18.04712 %, and the efficiency of photoelectric conversion increased to 0.124 %. In addition, according to the results of the confirmation runs, the AZO film was polymorphic. These experimental results confirm the effectiveness of RF magnetron sputtering, which provides high reflectivity and photoelectric conversion efficiency.

Integrated microwave photonic notch filter using a heterogeneously integrated Brillouin and active-silicon photonic circuit

Microwave photonics (MWP) has unlocked a new paradigm for Radio Frequency (RF) signal processing by harnessing the inherent broadband and tunable nature of photonic components. Despite numerous efforts made to implement integrated MWP filters, a key RF processing functionality, it remains a long-standing challenge to achieve a fully integrated photonic circuit that can merge the megahertz-level spectral resolution required for RF applications with key electro-optic components. Here, we overcome this challenge by introducing a compact 5 mm × 5 mm chip-scale MWP filter with active E-O components, demonstrating 37 MHz spectral resolution. We achieved this device by heterogeneously integrating chalcogenide waveguides, which provide Brillouin gain, in a complementary metal-oxide-semiconductor (CMOS) foundry-manufactured silicon photonic chip containing integrated modulators and photodetectors. This work paves the way towards a new generation of compact, high-resolution RF photonic filters with wideband frequency tunability demanded by future applications, such as air and spaceborne RF communication payloads.

Recent advances in food processing by radio frequency heating techniques: A review of equipment aspects

Radio frequency (RF) treatment, as an emerging thermal technology, has been studied for various purposes in food processing. In addition to optimal design of the RF processing conditions, the overall performance of the equipment is a key factor in determining the process efficiency and product quality. Although different types and scales of RF equipment have been used in food processing, the growing demand has exposed certain drawbacks of the RF equipment applications, especially for the heating uniformity, convenience of operation, treating efficiency, and product quality, and therefore, custom designed or combined equipment based on the specific application scenarios has attracted wider attentions. This paper systematically reviews the current state on applications of RF equipment for various purposes of food processing. The heating principles, typical equipment, customized accessories, and combination modes of RF systems are summarized, and some important findings and conclusions are provided in detail. Moreover, the challenges and future directions of RF equipment used in food processing are also discussed, which may help to better design and optimize RF equipment used for future food processing. This review would improve the understanding of RF equipment for food processing and promote the application of RF technology in the industrial scale.

RF-PSF: A CNN-Based Process Distinction Method Using Inadvertent RF Signatures

Stochastic variation of process parameters within a die and technology-limitation-driven variation from die-to-die give rise to unique distribution patterns for manufacturing process parameters. These patterns work as a process signature that is transferred from the device level to the system level through electrical circuits and can be used to make a distinction among the processes. In this work, we propose an in-situ manufacturing process technology distinction method‘, Radio Frequency Process Specific Functions (RF-PSF)’, that uses process-specific inherent properties of an IC manifested in the transmitted radio frequency signal. Among many desirable testing criteria, RF-PSF addresses the question of fabrication with the intended process technology. This information plays an important role in modern zero-trust architecture and IC clone detection, a counterfeiting method where the IC is manufactured using a different process. An RF transmitter with RF-DAC power amplifier for QPSK modulation has been designed and simulated in 14nm, 22nm, and 65nm processes for 5 process corners (TT, FF, FS, SF, and SS) in Cadence. The simulated data have been processed in MATLAB. A Multilayer Perceptron (MLP), trained with the constellation data, provides an average accuracy of ~90% for process distinction. Realizing that (i) a higher order modulation will have even more process information and (ii) we can harness the Convolutional Neural Network’s (CNN) improved capability on pattern recognition, we can feed image-like constellation plots to a CNN to get better and consistent performance. Using the baseband constellations for 64-QAM modulated data as images, we have achieved ~100% accuracy with commonly used, pretrained CNN models (ResNet18, ResNet50, and GoogleNet) through transfer learning. The separation among 5 process corners within a process, termed intra-process variation, is also analyzed. The effect of baseband sampling rate and ADC resolution, two practical limitations in RF systems, have been explored. An extensive study has been performed on the effect of a key design parameter at the RF circuit level i.e. W/L or aspect ratio, leading to design insights, proper CNN selection, and some control parameters. This work establishes RF-PSF as a zero-power, zero-area overhead, in-situ process distinction method.

Effect of radio frequency energy on buckwheat quality: An insight into structure and physicochemical properties of protein and starch

Radio frequency (RF) heating as an emerging technology is widely used to improve cereal-based food quality. To further investigate effects of RF treatment on buckwheat quality, structures and physicochemical properties of protein and starch in buckwheat were evaluated under various temperatures (80, 90, and 100 °C) and holding times (0, 5, and 10 min). Results showed that protein-starch complexes were reaggregated with the increases of RF heating temperature and time, as well as the values of R1047/1022, crystallinity, random coil, and α-helix significantly decreased, and the values of β-sheet obviously increased. Moreover, viscosities and rheological properties of buckwheat were reduced by the raised RF treatment intensity. Besides, the RF processing had a mostly positive effect on swelling power at low temperature of 30 °C, but contrary effect at high temperatures of 60 °C and 90 °C. However, changes of water solubility index, emulsifying capacity, and emulsion stability depended on the RF processing intensity. These results of the study suggested that buckwheat quality was affected by multiple RF treatment conditions, which can be tailored to develop a RF process having the potential to improve the function of buckwheat flour.

Non-thermal effect of radio frequency treatments verified by the multi-scale structure and in-vitro digestibility of sweet potato starch

To verify whether there is a non-thermal effect in the radio frequency (RF) heating process, a heat block (HB) system was used to simulate the RF process for excluding the influence of thermal effect. Sweet potato starch (SNS) slurry was treated to 60 °C by RF and HB systems with different heating rate, while the heat uniformity was determined to ensure the feasibility and reliability of the method and results. The long- and/or short - range structural, molecular, and digestive characteristics of samples were investigated to elucidate the difference of the RF and HB treatments. The X-ray diffraction patterns (XRD) analysis demonstrated that crystal pattern remained A-type, but the crystallinity of treated samples was significantly reduced. Compared with HB treatment, the RF- treated starch had a more compact, or ordered structure, higher z-average radius of gyration (Rz), peak viscosity (PV) and setback (SB) based on small angle X-ray scatter (SAXS), Fourier-transform infrared spectra (FTIR), size-exclusion chromatography (SEC) and pasting properties observations, respectively. Especially, RF- treated starches with higher heating rate had lower weight-average molar mass (Mw), rapidly and slowly digestive starch content, resulting in the highest resistant starch content and polydispersity index (PDI) in comparison with other samples. The structural characteristics and digestibility of starch were significantly different between RF and HB treatments under the same conditions. This study may provide valuable insights into the thermal and non-thermal effects of RF treatment on starch structure to broaden the application of RF heating in the food processing filed.

RF Frequency Selective Switch by Multiple PMIM Conversions

Nowadays, broadband and multi-channel radio frequency (RF) processing has been widely used in communication, radar, countermeasure, and other applications. At present, multiple-input and multiple-output (MIMO)-oriented microwave photonic signal processing technology is relatively scarce, so this paper proposes an RF frequency selective switch (FSS) based on multiple phase modulation to intensity modulation (PMIM) conversions. PMIM conversion has been used in narrowband microwave photonic filtering in the past. We extend it to a wideband and arbitrarily reconfigurable RF spectrum processing unit through an optical frequency comb and periodic optical filter. Although we use the incoherent combination of a multi-wavelength light source, we can obtain any frequency response including rectangles only by using all positive tap coefficients. Using an optical wavelength selective switch (WSS), we obtain RF FSS, and the spectral resolution of RF FSS is much better than that of optical WSS, which is improved by more than two orders of magnitude. The above principles, including single-channel reconfigurable filtering and multi-channel RF FSS, are verified by experiments. Our technology provides a stable solution for future RF MIMO signal processing.

Functionality of Soft Wheat Flour Treated by Radiofrequency Assisted Thermal Processing

Highlights Functionality of RF processed soft wheat flour (SWF) in the sugar-snap cookies was evaluated. Functionality of the SWFs at RF processing conditions of 80°C for 7 h and 90°C for 2 h is acceptable. Study demonstrated the feasibility of RF-assisted thermal processing of SWF. ABSTRACT. Wheat flours are thermally processed to ensure microbiological safety for use in food products such as cakes, cookies, baby foods, etc. Traditional thermal processing of wheat flour takes a long time because of its poor thermal conductivity. Novel thermal processing methods, such as radiofrequency assisted processing, are poised to replace the traditional methods. However, to ensure the final acceptance and adaptability of novel methods, the performance of RF-processed flours in prepared products such as cookies and noodles is important. The objective of this study is to evaluate the functionality of radiofrequency (RF)-assisted thermally processed soft wheat flour (SWF) in the end products, namely sugar-snap cookies. Sugar-snap cookies were prepared from RF-processed, unpasteurized, and commercially processed SWFs following a standard method. The qualities of the prepared cookies, such as width, thickness, etc., were evaluated and compared. The width of the sugar-snap cookies of the RF-assisted thermal process conditions of 80°C for 7 h and 90°C for 2 h was not significantly (P > 0.05) different from that of the unpasteurized SWF. The cookie thickness for all the RF-assisted thermally processed conditions was significantly higher than that of the unpasteurized condition. However, the color, hardness, and fracturability values of sugar-snap cookies were not significantly different at all the RF-assisted thermal processing conditions when compared with those of the unpasteurized condition. The functionality of the flours in sugar-snap cookies indicates that the selected RF-assisted thermal processing temperatures and time combinations of 80°C for 7 h and 90°C for 2 h did not influence the functionality of the SWF significantly. Thus, this study demonstrates the feasibility of novel RF-assisted thermal processing of SWF without compromising the flour's functionality in the end products. Keywords: Click here to enter keywords and key phrases, separated by commas, with a period at the end

Realization of GHz band integrated optical links in a radio frequency Si Ge bipolar process operating at 650 to 850 nm wavelength

A series of on-chip optical links of 50-μm length, utilizing 650 to 850 nm propagation wavelength, with Si avalanche-mode optical sources, silicon nitride-based waveguides, and Si Ge detectors, have been designed and realized, with a 0.35-μm SiGe radio frequency bipolar integrated circuit process. The optical coupling between the optical source and the detectors was realized by a set of dedicated designed optical waveguides, which were all fabricated with components of the SiGe radio frequency process. All components were fully integrated on the same silicon chip. The Si avalanche-mode light-emitting diodes (Si AMLEDs) emitted in the 650- to 850-nm wavelength regime. Correspondingly, small microdimensioned detectors utilize SiGe detector technology with detection efficiencies of up to 0.85 in the same wavelength regime and with a transition frequency of up to 20 GHz. Best performances for the optical links as realized show optical coupling of up to 5 GHz with a total optical link budget loss of −40 dB. A set of link results are presented and several interpretations are given on current realizations. The technology is particularly suitable for realization of low-cost on-chip optical signal processing, optical interconnects, and various types of on-chip microsensors.

An innovative computational design for air impingement coupled radio frequency thawing process

Radio frequency (RF) processing, with its volumetric heating ability and a longer wavelength, is applied in industrial thawing and tempering processes for larger-sized frozen food products. However, overheating problems are observed at corners and edges of (specifically the sharp-edged foods) with a significant temperature non-uniformity, and tempering is preferred with its limited temperature increase right below the freezing point in most cases. The distance between the electrodes, charged electrode potential, and sample-electrode moving conditions in industrial-scale systems were investigated for temperature uniformity in the literature, but there has not been a confirmed solution presented for thawing yet. Therefore, air impingement coupled with RF heating was presented in this computational study using a previously (experimentally) validated model. Computational studies were carried out using Comsol Multiphysics for process design purposes, and RF system geometries included single and double cavity configurations with an air impingement speed of 0.5 and 2.5 m/s in a slot jet application. Significant temperature distribution uniformity was obtained within the samples even at higher electrode potentials, and air impingement coupled RF systems were presented for industrial-scale process conditions. 2750 V potential and 2.5 m/s air impingement speed were the optimal process condition for both single and double cavity RF systems. The results of this study are expected to be further used for system design and process optimization for industrial-scale RF thawing applications.

Effect of radiofrequency processing on the structural and bio-functional properties of egg white proteins

Radiofrequency (RF) assisted thermal processing can significantly enhance the gel firmness of egg white powder compared to the traditional hot room (HR) processing. Thus, the present study aims to delineate the impact of RF processing on the proteins' structure and bio-functional properties of egg white protein gels. The secondary protein conformations of egg white proteins exhibited no significant alteration upon RF-assisted thermal processing over traditional HR processing. In-vitro gastrointestinal (GI) digestion of egg white gels demonstrated that the RF processing did not compromise the accessibility of digestive proteases despite a more robust gel network. Peptides from the GI digest of egg white gel showed that Ovalbumin and Ovotransferrin were the parent proteins of most of the unique peptides generated, and minor structural differences accounted for these peptides. The bioavailability of the egg protein-derived peptides remains unaffected after RF processing without compromising the viability and integrity of the GI epithelial cells.

Use of plasma oxidation for conversion of metal salt infiltrated thin polymer films to metal oxide

Oxygen plasma treatments for conversion of metal salt infiltrated polymer films to metal oxide films using an asymmetrical capacitively coupled plasma system were investigated. Hydroxylated Poly-2-Vinylpyridine (P2VP-OH) thin films grafted to silicon were exposed to metal salt-solvent solutions which swell the polymer enabling metal ion infiltration. Exposing the resulting film to oxygen plasma resulted in formation of polymer-free metal oxide films. Atomic oxygen and positive ions present in plasma can both influence the process outcome. A design of experiment approach was used to investigate the impact of radio frequency (RF) power, gas pressure and process time on plasma composition and the resulting metal oxide films. A combination of Langmuir probe, retarding field energy analyser and optical emission spectroscopy measurements were used to monitor the plasma. The samples surfaces were examined using x-ray photoelectron spectroscopy, ellipsometry, transmission electron microscopy and energy dispersive x-ray analysis. Gas pressure and RF power were found to strongly influence both ion energy, and atomic oxygen to molecular ion ratios [O]/[O2 +] in the plasma which impacted the resulting surface layer. For the plasma conditions investigated conversion to a metal oxide was achieved in minutes. Sputter contamination was found to be significant in some cases.

Determination of dielectric properties and predictive modeling for designing radio-frequency heating of ground beef

Dielectric properties of ground beef as affected by the variation of fat content (73/27, 80/20, and 85/15 lean/fat) and temperature (0–90 °C) were determined using a parallel plate LCR meter and liquid test fixture at the radiofrequency (RF) of 27.12 MHz. The values of dielectric constant (ε′) and dielectric loss factor (ε'') of ground beef significantly increased with temperature (p < 0.05) whereas the values of penetration depth (dp) decreased with temperature (p < 0.05) up to the respective points of local extrema. Values of both ε′ and ε'' were significantly lower (p < 0.05) for the leaner blend 85/15 and conversely, penetration depth was significantly higher (p < 0.05) for the leaner blend. As temperature increased beyond the point of maximum for ε′ and ε'' and point of minimum for dp, there was no significant difference in the dielectric properties between the different lean/fat blends. Predictive equations of second order in temperature and fat content were developed for the dielectric properties which explained 74, 93, and 98% variation in ε′, ε'', and for dp respectively, based on R2 values. The dielectric properties and their fitted models can be utilized for designing pilot and mass scale RF processes for heating ground beef.

IndexPen

In this paper, we introduce IndexPen, a novel interaction technique for text input through two-finger in-air micro-gestures, enabling touch-free, effortless, tracking-based interaction, designed to mirror real-world writing. Our system is based on millimeter-wave radar sensing, and does not require instrumentation on the user. IndexPen can successfully identify 30 distinct gestures, representing the letters A-Z, as well as Space, Backspace, Enter, and a special Activation gesture to prevent unintentional input. Additionally, we include a noise class to differentiate gesture and non-gesture noise. We present our system design, including the radio frequency (RF) processing pipeline, classification model, and real-time detection algorithms. We further demonstrate our proof-of-concept system with data collected over ten days with five participants yielding 95.89% cross-validation accuracy on 31 classes (including noise). Moreover, we explore the learnability and adaptability of our system for real-world text input with 16 participants who are first-time users to IndexPen over five sessions. After each session, the pre-trained model from the previous five-user study is calibrated on the data collected so far for a new user through transfer learning. The F-1 score showed an average increase of 9.14% per session with the calibration, reaching an average of 88.3% on the last session across the 16 users. Meanwhile, we show that the users can type sentences with IndexPen at 86.2% accuracy, measured by string similarity. This work builds a foundation and vision for future interaction interfaces that could be enabled with this paradigm.

Design and Fabrication of X-Y Gantry Mechanism using Python: A Review

Abstract: A crane is a machine that is primarily used to handle big weights in a variety of jobs. For instance, building work, shipbuilding, cargo transportation, and the cement industry may all benefit from this technology since it allows them to monitor and control their video processing systems using a PC. Cranes are frequently utilized in the industrial sector around the world to boost productivity and minimize personnel. Cranes are used to transport loads from one location to another. During this movement, there are typically unwanted vibrations and variations in the hoisted weight that must be managed. This paper gives a review of a new way for operating an overhead crane that uses a PC (Portable Computer), RF (Radio Frequency), and video processing approach to operate the crane from a certain distance. The crane movement is now controlled directly by the crane operator; nevertheless, due to the human inability to handle the crane efficiently, the crane speed is severely limited. This procedure allows a single employee to handle the crane from a greater distance by watching the location of each and every movement towards and away from the crane using a video processing technology and a radio frequency controlling system. The technology use computer vision to identify load location, which is then used to optimize crane operation. The intimation of the PC monitors reveals that the accident levels to become decline for handling the overhead crane even by operator, according to the technology for sustaining job.