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The Present study was conducted to extract tomato seed oil using emerging technologies which include moderate electric field (MEF), low temperature microwave (MW), radio-frequency (RF), power ultrasound (US) and combined low temperature microwave-power ultrasound (MWUS) at different solid to liquid (S/L) ratio and power level. A green solvent (ethanol: ethyl acetate) was used to extract the oil from tomato seed and a mass transfer kinetic study was studied to find the extraction kinetics and effect of different treatments. MWUS assisted extracted oil was observed to have the highest extraction yield (23.07%) as well as the best quality of oil extracted. The extracted oil using MWUS treatment was mainly composed of PUFA (Linoleic acid), MUFA (Oleic acid) and Stearic acid. Low temperature microwave-ultrasound assisted extraction (MUAE) increased the linoleic, stearic and oleic acid content by 30.91, 5.16 and 7.29% respectively in tomato seed oil composition compared to the conventional Soxhlet extraction (SXE) method. The novel 'Low temperature microwave-ultrasound assisted extraction (MUAE)' technology presents a promising result combination of emerging technology for the extraction of oil. The impact of low temperature dipole moment of microwave followed by low intensity ultrasound cavitation leads to the breakdown of the tomato seed matrix. Further, this combination improved the extraction yield although the solvent used very lower solubility compared to conventional solvents. The quality of the extracted oil following MUAE technology was found to be much better than conventional extraction. Hence this combination presents a good scope for application in the food industry, with good commercial value and being environmentally friendly makes it more acceptable. [Display omitted] • RAE, MAE and MUAE is proposed first time for tomato seed oil extraction. • MUAE treatment recovered higher unsaturated fatty acid content. • MUAE treatment had highest oil yield and retained oil quality. • Oil extraction kinetics was well explained by Fick's law of diffusion. [ABSTRACT FROM AUTHOR]

Competing Interests: Funding Support and Author Disclosures The authors have reported that they have no relationships relevant to the contents of this paper to disclose.

Many prevalent heart diseases can be indicated by the features of the jugular venous pulse (JVP), an efficacious indicator of right heart health. However, JVP dynamics are not widely utilized in clinical settings as its observation and sensing remain cumbersome. Non-invasive measures of cardiac behavior, including the JVP, are of growing interest to enable continuous and at-home monitoring of cardiac disorders. In this work, we propose a wearable near-field radio-frequency (RF) sensor affixed with a neck collar on the clavicle over the internal jugular vein to enable non-invasive JVP sensing. We employed a complex vector injection signal processing method to extract repeatable JVP waveform features in multiple postures. With a 21-subject human study, we demonstrated morphologically consistent JVP sensing with consistent a-, c-, and v-wave feature timings, benchmarked by synchronous electrocardiogram and phonocardiogram. Further, inter-postural experiments demonstrated the capability of the proposed system to quantify morphological changes to the JVP which are present in many cardiac disorders. The results of this work suggest the proposed near-field RF sensor is capable of non-invasive JVP monitoring, potentially enabling improved sensing in both clinical and ambulatory environments.

In the first part of the paper, we modeled and characterized the underwater radio channel in shallowwaters. In the second part, we analyze the application requirements for an underwaterwireless sensor network (U-WSN) operating in the same environment and perform detailed simulations. We consider two localization applications, namely self-localization and navigation aid, and propose algorithms that work well under the specific constraints associated with U-WSN, namely low connectivity, low data rates and high packet loss probability. We propose an algorithm where the sensor nodes collaboratively estimate their unknown positions in the network using a low number of anchor nodes and distance measurements from the underwater channel. Once the network has been self-located, we consider a node estimating its position for underwater navigation communicating with neighboring nodes. We also propose a communication system and simulate the whole electromagnetic U-WSN in the Castalia simulator to evaluate the network performance, including propagation impairments (e.g., noise, interference), radio parameters (e.g., modulation scheme, bandwidth, transmit power), hardware limitations (e.g., clock drift, transmission buffer) and complete MAC and routing protocols. We also explain the changes that have to be done to Castalia in order to perform the simulations. In addition, we propose a parametric model of the communication channel that matches well with the results from the first part of this paper. Finally, we provide simulation results for some illustrative scenarios. [ABSTRACT FROM AUTHOR]

Background: Spontaneous magnetic alignment (SMA), in which animals position their body axis in fixed alignments relative to magnetic field lines, has been shown in several classes of vertebrates and invertebrates. Although these responses appear to be widespread, the functional significance and sensory mechanism(s) underlying SMA remain unclear. An intriguing example comes from observations of wild red foxes (Vulpes vulpes) that show a ~four fold increase in hunting success when predatory 'mousing' attacks are directed toward magnetic north-northeast. This form of SMA is proposed to receive input from a photoreceptor-based magnetoreception mechanism perceived as a 'visual pattern' and used as a targeting system to increase the accuracy of mousing attempts targeting hidden prey. However, similar to previous observational studies of magnetic orientation in vertebrates, direct evidence for the use of magnetic cues, and field-based experiments designed to characterize the biophysical mechanisms of SMA are lacking. Here, we develop a new approach for studies of SMA using triaxial accelerometer and magnetometer bio-loggers attached to semidomesticated red foxes. Results: Accelerometer data were recorded from 415 ground-truth events of three behaviors exhibited by an adult red fox. A 5-nearest neighbor classifier was developed for behavioral analysis and performed with an accuracy of 95.7% across all three behaviors. To evaluate the generalizability of the classifier, data from a second fox were tested yielding an accuracy of 66.7%, suggesting the classifier can extract behaviors across multiple foxes. A similar classification approach was used to identify the fox's magnetic alignment using two 8-way classifiers with differing underlying assumptions to distinguish magnetic headings in eight equally spaced 45° sectors. The magnetic heading classifiers performed with 90.0 and 74.2% accuracy, suggesting a realistic performance range for a classifier based on an independent set of training events equal in size to our sample. Conclusions: We report the development of 'magnetic ethograms' in which the behavior and magnetic alignment of foxes can be accurately extracted from raw sensor data. These techniques provide the basis for future studies of SMA where direct observation is not necessary and may allow for more sophisticated experimental designs aimed to characterize the sensory mechanisms mediating SMA behavior. [ABSTRACT FROM AUTHOR]

We experimentally demonstrate an all-optical approach for generating frequency-shift keying (FSK) radio-frequency (RF) signal based on nonlinear polarization rotation (NPR) in a highly nonlinear fiber (HNLF). A continuous wave probe beam is polarization-rotated by an optical amplitude-shift keying control beam via NPR in the HNLF. After removing the undesired control beam by a tunable optical filter, the polarization-rotated probe beam is converted to an intensity-modulated optical signal using a polarizer. By carefully adjusting the polarization controller before the polarizer and the optical power of the control beam, FSK RF signals are generated after photodetection. [ABSTRACT FROM AUTHOR]

A novel symmetrical SOI-MESFET is reported to enhance high-voltage and radio-frequency performances, successfully. Two p-type cavity regions with certain features are embedded in the proposed structure to control the channel region. The cavity regions absorb the channel potential lines resulting in an evener potential profile throughout the channel region. Hence, the critical electric field at the end of gate edge near the drain will be considerably reduced thus increasing the breakdown voltage, finally. A comprehensive comparison in terms of breakdown voltage, radio-frequency parameters, drain-source conductance and minimum noise figure shows that the reported new device reaches a superior electrical performance when compared with a conventional SOI MESFET. [ABSTRACT FROM AUTHOR]

Radio-frequency (RF) homogeneous dielectric barrier discharge (DBD) is compared to low frequency glow DBD to make silicon oxide from Ar/NH3/SiH4. RF-DBD is a more powerful discharge, and the growth rate is not limited by precursor dissociation rate but by powder formation. Powders are not deposited in the plasma zone but in the post-discharge due to their trapping by the electric field. Modulation of the RF-DBD is a useful solution to avoid powder formation. Powders are systematically avoided if the plasma energy during time on stays below 750 µJ. RF-DBD modulation also increases the growth rate twofold compare to continuous RF. The optimum growth rate without powder corresponds to a short Ton to limit precursor dissociation, a long Toff to enhance diffusion and a fast repeat frequency to increase deposition rate. [ABSTRACT FROM AUTHOR]

This paper present a comprehensive analysis of LC Colpitts Oscillator built around a DGMOS (Double Gate Metal Oxide Semiconductor) transistor using high-k technology. A mixed- mode simulation is involved, applying a quantum model to the device whereas the rest of the considered circuit is governed by Kirchhoff‟s laws. The quantum device model correspond to 2D numerical calculations based on self- consistent codes coupling Poisson and Schrödinger equation along the transport direction, considering an effective mass approximation. A comparison with Drift Diffusion model (DDM) is made in order to point out importance of quantum effect in this nanometer device. The impact of high-k oxide gate is investigated and analyzed; the results confirm that the high-k is an interesting alternative to reduce tunneling gate current of the DGMOS transistor but reach the same drain one. Considering the oscillator, our goal is focused on the analysis of its phase noise. The Linear Time Variant (LTV) model of phase noise is considered. It is based on the Impulse Sensitivity Function (ISF) which describes carefully the sensitivity of an oscillator to a parasite impulse current injection in different nodes of the circuit. The obtained results pointed out that the ISF function is sinusoidal and its period is nearly the same of the oscillator output signal for different dielectric oxide. It also states that the phase noise of a Colpitts oscillator is not affected by the use of the high-k materials. Finally this method, if extended, is a good tool to investigate a perturbation response on such circuits. [ABSTRACT FROM AUTHOR]

We present a new diagnostic technique of fundamental monomeric biomaterials that do not rely on any enzyme or chemical reaction. Instead, it only uses radio frequency (RF) signal analysis. The detection and classification of basic biomaterials, such as glucose and albumin, were demonstrated. The device was designed to generate a strong resonance response with glucose solution and fabricated by simple photolithography with PDMS (Polydimethylsiloxane) well. It even was used to detect the level of glucose in mixtures of glucose and albumin and in human serum, and it operated properly and identified the glucose concentration precisely. It has a detection limit about 100 μM (1.8 mg/dl), and a sensitivity about 58 MHz per 1 mM of glucose and exhibited a good linearity in human blood glucose level. In addition, the intrinsic electrical properties of biomaterials can be investigated by a de-embedding technique and an equivalent circuit analysis. The capacitance of glucose containing samples exhibited bell-shaped Gaussian dispersion spectra around 2.4 GHz. The Albumin solution did not represent a clear dispersion spectra compared to glucose, and the magnitude of resistance and inductance of albumin was higher than that of other samples. Other parameters also represented distinguishable patterns to classify those biomaterials. It leads us to expect future usage of our technique as a pattern-recognizing biosensor. [ABSTRACT FROM AUTHOR]

This paper presents an experimental evaluation of the first commercial scale dry-sort-redry (DSRD) strategy for drying of 2x4 Pacific coast hemlock (PCH) lumber. The DSRD strategy is a methodology designed to reduce final moisture content variability in kiln dried lumber by complementing conventional drying with radio frequency vacuum (RFV) drying technology. The strategy′s objective is to avoid producing over-dried lumber in conventional drying by setting the target moisture content to a value much higher than those usually used in industry. Then, RFV drying technology is implemented to quickly and efficiently re-dry the lumber that remains wet (under-dried) after the first conventional pass. Six experimental tests were performed in an industrial sawmill with the intention of studying the effect of target moisture content on the properties and quality of the dried lumber. In all cases, the first drying pass was performed in a 260m³ industrial heat-and-vent conventional kiln, and the re-drying of wets was performed in a 75m³ RFV kiln. Additionally, a mathematical model developed for prediction of data dispersion in lumber drying was calibrated with experimental data, and used to simulate the DSRD strategy under other hypothetical conditions. The results of the study demonstrate that the DSRD strategy reduces drying time, shrinkage and kiln drying degrade in comparison with a single conventional pass

• Automated image-free ultrasound signal-processing technique for arterial wall recognition and motion tracking. • The method discerns presence and absence of arterial wall echoes in one-dimensional A-scans. • Recognition and tracking are robust to noise, any hyper-echoic regions or slow-moving structures adjacent to arterial walls. • The method supports development of inexpensive A-mode ultrasound systems. • It operates in real-time and is promising for large-scale field studies and resource-constrains settings. Current ultrasound methods for recognition and motion-tracking of arterial walls are suited for image-based B-mode or M−mode scans but not adequately robust for single-line image-free scans. We introduce a time-warping-based technique to address this need. Its performance was validated through simulations and in-vivo trials on 21 subjects. The method recognized wall locations with 100 % precision for simulated frames (SNR > 10 dB). Clustering detections for multiple frames achieved sensitivity >98 %, while it was ∼90 % without clustering. The absence of arterial walls was predicted with 100 % specificity. In-vivo results corroborated the performance outcomes yielding a sensitivity ≥94 %, precision ≥98 %, and specificity ≥98 % using the clustering scheme. Further, excellent frame-to-frame tracking accuracy (absolute error <3 %, RMSE <2 μm) was demonstrated. Image-free measurements of peak arterial distension agreed with the image-based ones, within an error of 1.08 ± 3.65 % and RMSE of 38 μm. The method discerned the presence of arterial walls in A-mode frames, robustly localized, and tracked them even when they were proximal to hyperechoic regions or slow-moving tissue structures. Unification of delineation techniques with the proposed methods facilitates a complete image-free framework for measuring arterial dynamics and the development of reliable A-mode devices. [ABSTRACT FROM AUTHOR]

This paper presents an experimental evaluation of the first commercial scale dry-sort-redry (DSRD) strategy for drying of 2x4 Pacific coast hemlock (PCH) lumber. The DSRD strategy is a methodology designed to reduce final moisture content variability in kiln dried lumber by complementing conventional drying with radio frequency vacuum (RFV) drying technology. The strategy’s objective is to avoid producing over-dried lumber in conventional drying by setting the target moisture content to a value much higher than those usually used in industry. Then, RFV drying technology is implemented to quickly and efficiently re-dry the lumber that remains wet (under-dried) after the first conventional pass. Six experimental tests were performed in an industrial sawmill with the intention of studying the effect of target moisture content on the properties and quality of the dried lumber. In all cases, the first drying pass was performed in a 260m3 industrial heat-and-vent conventional kiln, and the re-drying of wets was performed in a 75m3 RFV kiln. Additionally, a mathematical model developed for prediction of data dispersion in lumber drying was calibrated with experimental data, and used to simulate the DSRD strategy under other hypothetical conditions. The results of the study demonstrate that the DSRD strategy reduces drying time, shrinkage and kiln drying degrade in comparison with a single conventional pass.

Hydrogen is a very attractive source of highly efficient and environmentally friendly energy. Investigation into hydrogen production from glucose decomposition by 27.12 MHz radio-frequency in-liquid plasma with and without ultrasonic vibrations was carried out utilizing 29 kHz and 1.6 MHz ultrasonic transducers to determine the effects of agitation and acoustic streaming. In-liquid plasma is generated inside a bubble, resulting in a high temperature chemical reaction field within the liquid which is then irradiated by ultrasonic vibration. The dependence of hydrogen production rate, hydrogen yield, hydrogen purity and hydrogen production efficiency on the types of ultrasonic vibration applied was investigated. Higher intensities of active C atoms species were observed in the emission spectrum of RF in-liquid plasma when irradiated with ultrasonic vibration and it is believed that these species function as precursors or intermediaries for other components in the gas product. Hydrogen production rate was enhanced by 30% when RF in-liquid plasma was irradiated by the 1.6 MHz piezoelectric transducer. The highest hydrogen yield was 72% for RF in-liquid plasma with the 29 kHz ultrasonic transducer at an initial concentration 1.0%. The hydrogen purity was enhanced by 5% for the highest initial concentration when applying the 29 kHz ultrasonic transducer to the RF in-liquid plasma. Thus the acoustic streaming effect by 1.6 MHz piezoelectric vibration enhanced the hydrogen production rate, while on the other hand, the agitation effect by 29 kHz ultrasonic vibration enhanced hydrogen yield and hydrogen purity. Though the hydrogen production efficiency of RF in-liquid plasma with ultrasonic vibration applied was lower overall when compared to that without ultrasonic vibration except for decomposition of glucose 20 wt% by RF in-liquid plasma with 1.6 MHz ultrasonic transducer which was 7% higher than that without ultrasonic vibrations, this remains a process that could be considered as a promising future technique for hydrogen production. [ABSTRACT FROM AUTHOR]

Modern radio front ends are required to operate over diverse channel conditions requiring the incorporation of significant performance overheads into their design. This results in significantly higher power consumption over most of the operational period since the worst case channels are not statistically prevalent. Adaptive systems solve this problem by adapting the performance and power consumption depending on channel conditions. In this paper, it is demonstrated that depending upon the throughput requirements of the system multiple low-power adaptation modes can be designed. These modes ensure either highest throughput operation or lowest energy-per-bit operation. The operation of these modes is demonstrated in simulation using multiple-input-multiple-output (MIMO) receiver and transmitter front ends. Subsequently, the concepts are demonstrated in hardware for both MIMO and single-input-single-output front ends. [ABSTRACT FROM PUBLISHER]

Main goal of optimal thawing is to minimize thawing time with least damage to the quality of frozen food products. Microwave (MW) and radio frequency (RF) applications have potential for their use in industrial thawing. Higher penetration depths of RF contribute to a better distribution of energy generated by the interaction between food and electromagnetic field, and thus help to improve the heating uniformity and to minimize runaway heating. Modeling is one way to design and to optimize such process where complexities due to coupling the heat transfer with phase change and the solution of electric field are faced. Therefore, the objectives of this study were to develop a computational model to determine temperature distribution in frozen lean beef during thawing and experimentally validate the model. For this purpose, a commercial software, based on finite element method, was used to solve coupled heat conduction and electric field in a 3D domain with temperature dependent thermo-physical and dielectric properties. Experimental data used to validate the model referred to a 50 Ω and a free-running oscillator RF systems with various sized samples. Comparison of simulation results agreed well with experimental data, and the mathematical model was reported to be used for designing RF systems to mitigate the effect of overheating at the surfaces of the sample. [ABSTRACT FROM AUTHOR]

• Highly efficient solar cells were fabricated using different deposition methods. • Thin-film layers were fabricated at lower and higher deposition rates. • Plasma process was compared with catalytic deposition method. In this work an integration of two in-line deposition methods consisting of a linear hot-wire (HW) and very high frequency plasma enhanced chemical vapor deposition (VHF-PECVD) into a single in-line system for the fabrication process of highly efficient heterojunction solar cells was demonstrated. Using this continuous deposition methods, which are also well suited for roll-to-roll production, a high productivity can be achieved. In principle, the up-scaling of the electrode width is possible and no severe deterioration of the uniformity of the deposited layers is expected. With the linear configuration the homogeneity of the layer deposition has to be ensured in only one dimension (perpendicular to the movement direction of the substrate). The homogeneity in the second dimension is realized by the movement of the substrate at constant speed, thus the homogeneous deposition even on large area substrates is possible. In this work the individual steps for development of the passivation process using different in-line deposition methods were investigated. The results show that dynamic HW- and VH-PECVD technologies enables fabrication of the layers with high deposition rates and high passivation properties (carrier lifetimes > 13 ms) as well as highly efficient solar cells (efficiency > 22%). [ABSTRACT FROM AUTHOR]

In the first part of the paper, we modeled and characterized the underwater radio channel in shallowwaters. In the second part,we analyze the application requirements for an underwaterwireless sensor network (U-WSN) operating in the same environment and perform detailed simulations. We consider two localization applications, namely self-localization and navigation aid, and propose algorithms that work well under the specific constraints associated with U-WSN, namely low connectivity, low data rates and high packet loss probability. We propose an algorithm where the sensor nodes collaboratively estimate their unknown positions in the network using a low number of anchor nodes and distance measurements from the underwater channel. Once the network has been self-located, we consider a node estimating its position for underwater navigation communicating with neighboring nodes. We also propose a communication system and simulate the whole electromagnetic U-WSN in the Castalia simulator to evaluate the network performance, including propagation impairments (e.g., noise, interference), radio parameters (e.g., modulation scheme, bandwidth, transmit power), hardware limitations (e.g., clock drift, transmission buffer) and complete MAC and routing protocols. We also explain the changes that have to be done to Castalia in order to perform the simulations. In addition, we propose a parametric model of the communication channel that matches well with the results from the first part of this paper. Finally, we provide simulation results for some illustrative scenarios.

A combined low-noise amplifier and voltage-controlled oscillator (LNA-VCO) is implemented in a 0.13-µm CMOS technology. The low-power LC VCO and LNA circuits are stacked and share the same bias current. An LC filter is used between the LNA and the VCO to improve the isolation between the two functions. Based on the measurement results of the proof-of-concept prototype, the LNA achieves a gain of 18.4 dB and a noise figure (NF) of 3.8 dB at 2.4 GHz. The VCO has a center frequency of 2.45 GHz with a −5.3 dBm output power and a phase noise of −119 dBc/Hz at 1-MHz offset. The combined LNA-VCO block consumes 240 µW from a 0.8 V supply. [ABSTRACT FROM AUTHOR]

This article reviews radio-frequency (RF) biosensors based on passive and/or active devices and circuits. In particular, we focus on RF biosensors designed for detection of various biomolecules such as biotin-streptavidin, DNA hybridization, IgG, and glucose. The performance of these biosensors has been enhanced by the introduction of various sensing schemes with diverse nanomaterials (e.g., carbon nanotubes, graphene oxide, magnetic and gold nanoparticles, etc.). In addition, the RF biosensing platforms that can be associated with an RF active system are discussed. Finally, the challenges of RF biosensors are presented and suggestions are made for their future direction and prospects. [ABSTRACT FROM AUTHOR]

The aim of the current study was to investigate the validity and reliability of a radio frequency-based system for accurately tracking athlete movement within wheelchair court sports. Four wheelchair-specific tests were devised to assess the system during (i) static measurements; (ii) incremental fixed speeds; (iii) peak speeds; and (iv) multidirectional movements. During each test, three sampling frequencies (4, 8 and 16 Hz) were compared to a criterion method for distance, mean and peak speeds. Absolute static error remained between 0.19 and 0.32 m across the session. Distance values (test (ii)) showed greatest relative error in 4 Hz tags (1.3%), with significantly lower errors seen in higher frequency tags (<1.0%). Relative peak speed errors of <2.0% (test (iii)) were revealed across all sampling frequencies in relation to the criterion (4.00 ± 0.09 m · sˉ1). Results showed 8 and 16 Hz sampling frequencies displayed the closest-to-criterion values, whilst intra-tag reliability never exceeded 2.0% coefficient of variation (% CV) during peak speed detection. Minimal relative distance errors (<0.2%) were also seen across sampling frequencies (test (iv)). To conclude, the indoor tracking system is deemed an acceptable tool for tracking wheelchair court match play using a tag frequency of 8 or 16 Hz. [ABSTRACT FROM AUTHOR]

Aims Patients with well-tolerated sustained monomorphic ventricular tachycardia (SMVT) and left ventricular ejection fraction (LVEF) over 30% may benefit from a primary strategy of VT ablation without immediate need for a ‘back-up’ implantable cardioverter-defibrillator (ICD). Methods and results One hundred and sixty-six patients with structural heart disease (SHD), LVEF over 30%, and well-tolerated SMVT (no syncope) underwent primary radiofrequency ablation without ICD implantation at eight European centres. There were 139 men (84%) with mean age 62 ± 15 years and mean LVEF of 50 ± 10%. Fifty-five percent had ischaemic heart disease, 19% non-ischaemic cardiomyopathy, and 12% arrhythmogenic right ventricular cardiomyopathy. Three hundred seventy-eight similar patients were implanted with an ICD during the same period and serve as a control group. All-cause mortality was 12% (20 patients) over a mean follow-up of 32 ± 27 months. Eight patients (40%) died from non-cardiovascular causes, 8 (40%) died from non-arrhythmic cardiovascular causes, and 4 (20%) died suddenly (SD) (2.4% of the population). All-cause mortality in the control group was 12%. Twenty-seven patients (16%) had a non-fatal recurrence at a median time of 5 months, while 20 patients (12%) required an ICD, of whom 4 died (20%). Conclusion Patients with well-tolerated SMVT, SHD, and LVEF > 30% undergoing primary VT ablation without a back-up ICD had a very low rate of arrhythmic death and recurrences were generally non-fatal. These data would support a randomized clinical trial comparing this approach with others incorporating implantation of an ICD as a primary strategy. [ABSTRACT FROM PUBLISHER]

An electrical large-signal circuit model for a 30-W high-power laser diode module is presented. Such modules are designed primarily for continuous wave (cw) operation but can be pulsed in the sub- μs temporal range for special applications. Our model is thus valid up to 20 MHz in the electrical frequency domain. The elements of the circuit model have been derived from RF impedance measurements using a calibrated vector network analyzer and a high-current dc/RF bias-T. The impedance is dominated by the inductance of the high-current connecting leads from the laser driver to the laser chip. The skin effect has been found to influence considerably both resistive and inductive impedances at high frequencies. For large-signal circuit simulations in the time domain, the current-voltage characteristic of the diode p-n junction is included by an analytic equation. The model is verified by comparison of simulation results with measured currents, voltages, and laser powers in large-signal pulsed-mode operation. This model is well suited for the design of optimized pulsed-current driver circuits. [ABSTRACT FROM PUBLISHER]

Abstract: Radio-frequency atmospheric pressure plasma discharge as an inactivation technique was tested to reduce Staphylococcus aureus on the surface of polystyrene, agar, and beef jerky. S. aureus ATCC12600 was reduced by 3–4log colony forming unit on the polystyrene and agar after 2min treatment, but on beef jerky sample after 10min treatment. It suggests that the surface feature can significantly affect the inactivation of S. aureus by plasma. The scanning electron microscopy analysis showed that the S. aureus cells were disintegrated into pieces and many holes were created. The analysis of optical emission spectrum suggests that reactive oxygen species, especially the singlet state of oxygen at 777nm are mainly responsible for the inactivation and cellular deformation of S. aureus. No significant change was found in the fatty acid composition, color and shear force of the beef jerky samples (p >0.05). This study shows that radio-frequency atmospheric pressure plasma is effective in inactivation of S. aureus on the food samples such as beef jerky with little changes in nutritional and sensory qualities. Industrial relevance: Inactivation of S. aureus on polystyrene, agar, and beef jerky samples using radiofrequency atmospheric pressure plasma is presented. The plasma treatment was a useful technology to reduce a microbial contamination on the surface of thin and dehydrated food products such as beef jerky. It is promising in the industrial application since no significant change was found in the fatty acid composition, color, and shear force of the beef jerky after the plasma treatment. [Copyright &y& Elsevier]