Dual Circuit Research Articles

A Novel Dual Non-Invasive Ventilator Continuous Positive Airway Pressure Non-Aerosolization Circuit for Emergency Use in the COVID-19 Pandemic

The COVID-19 pandemic is a public health emergency of unprecedented scale. The surge in clinical cases of patients with severe respiratory illness has overwhelmed the traditional capacity of healthcare systems worldwide. Continuous Positive Airway Pressure (CPAP) delivered through Non-Invasive Ventilation (NIV) has been shown to be useful in caring for patients with COVID-19. In particular patients with early stage milder acute hypoxemic respiratory failure can benefit from NIV CPAP therapy, though there is an acknowledged risk of COVID-19 aerosolization with traditional circuit use. Furthermore, given the surge in clinical care demand, there is an acute global shortage of ventilators, including NIV devices and therefore innovative methods are needed to increase NIV capacity and ameliorate infectious aerosolization. This paper outlines an emergency use modified dual NIV CPAP Circuit that uses a 3D printed splitter designed to work with traditional international NIV CPAP tubing standards and a 3D printed respiratory face mask knuckle to allow for distal expiratory breath exhalation through a viral filter rather than through an open to air proximal valve, which is the traditional NIV CPAP configuration. We expect that this work will increase global NIV CPAP capacity and ameliorate aerosolization of COVID-19 in patients undergoing therapy in an emergency scenario.

Alternative technique of long acting cardioplegia delivery results in less hemodilution.

Preparation of del-Nido cardioplegia and its delivery technique can cause significant hemodilution. The resultant effects from hemodilution are largely proportionate to the use of a dual circuit. We opted for a custom-disposable single cardioplegia circuit instead of a dual circuit. We describe an alternative technique of del-Nido cardioplegia delivery and initial clinical experience with it at National University Hospital, Singapore. This is a retrospective analysis of data from January 2017 to April 2019, comprising of 177 patients of heart surgery and reflecting a single center database survey under the National Health Care Group. Of the 177 patients who underwent surgery with del-Nido cardioplegia, 76 (42.9%) were valve-only procedures and 5 (2.8%) were coronary artery bypass graft-only procedures. Ultrafiltration was utilized in 132 (62.6%) patients, whereas filtrate volume was 2200 [150-9500] mL. The alternative technique of del-Nido cardioplegia delivery adopted by National University Hospital advocates for a single pump, single circuit system. The retrospective institutional data highlighted safe delivery of del-Nido cardioplegia using this technique in a range of procedures. Besides the safe delivery of del-Nido cardioplegia, the National University Hospital Technique reduces hemodilution and provides other technical benefits including a steeper temperature gradient, modification of circuit configuration to deliver another cardioplegia while on bypass, as well as re-configuration of clamps to spike the base solution.

Cross Interference Free Dual Frequency Wireless Power Transfer Using Frequency Bifurcation for Dynamic Biomedical Implants

Multiple biomedical implants are used in different applications to monitor the functions of living cells. The inductive resonant coupled wireless power transfer (WPT) has been investigated extensively to increase the lifetime and reduce the battery size of implants. The concurrent WPT to multiple devices is one of the unique features of inductive resonant coupling. However, the cross-coupling among the multiple implants during the concurrent power transfer raises the issue of interference between the implants. It affects both the power and data transfer rate, which leads to malfunction of implantable sensor. This article proposes a simple and effective approach of eliminating cross interference using resonant frequency bifurcation technique. Two overcoupled resonant coil structures are investigated at the transmitter (Tx) side to concurrently power two implants that are non-stationary. In addition, a dual frequency impedance matching circuit is developed to maintain the required bifurcated frequency at the Tx section regardless of changes in coupling between implanted coil and Tx side coil. The simulation and experimental outcomes predict that the proposed technique is able to provide 29.35% of power transfer efficiency at the chosen source frequency of 6.78 MHz.

Temperature Dependence of Hippocampal Short‐term Facilitation (STF) in Syrian Hamsters, a Hibernating Species

Studies on non‐hibernating mammals have identified short‐term facilitation (STF) as a form of cellular neural plasticity that modulates information processing over a hippocampal neural network of CA3 and CA1 pyramidal neurons. The circuit has two branches: (1) a monosynaptic excitatory (E) feedforward pathway wherein CA3 axons directly excite CA1 neurons, and (2) a bi‐synaptic inhibitory (I) feed‐forward pathway. Pathway I includes a GABAergic inhibitory neuron such that CA3 axons excite GABAergic interneurons that in turn inhibit CA1 neurons. The present study evaluated the possibility that such a dual feedforward circuit supported STF in hibernating as well as in non‐hibernating Syrian hamsters (Mesocricetus auratus). We tested the hypotheses that: (1) at temperatures at (or above) 25° C, the hamster’s circuits support STF as in non‐hibernating species, and (2) as temperature declines from 25° to 20° (simulating brain temperatures encountered during entry into torpor), STF is attenuated. For this, we evaluated responses in 400μ hamster hippocampal slices, using tungsten stimulating electrodes placed to excite CA3 axons (Schaffer collaterals/commissural fibers) and a glass electrode positioned to record CA1 neuron evoked responses (fEPSPs). Paired‐pulse stimulation (with an interpulse interval of 30 msec and an interval between pairs of 60 sec) evoked a pair of responses – i.e., fEPSP1 followed fEPSP2. With bath temperature at (or above) 25° C, the initial slope of fEPSP2 was greater than that of fEPSP1. This finding supports the presence of a hamster facilitating circuit with at least an E feedforward pathway linking CA3 and CA1 neurons. To determine if the hamster circuit also has a bi‐synaptic inhibitory branch, paired‐pulse experiments were repeated in the presence and absence of picrotoxin, a non‐competitive GABA receptor antagonist. Picrotoxin altered fEPSP1 and fEPSP2 slopes (e.g., when GABAergic interneurons were blocked, fEPSP1 slope increased), indicating the hamster circuit also had an inhibitory feedforward branch. Additionally, paired‐pulse experiments with bath temperature lowered to 20° C resulted in a decreased ratio of fEPSP2/fEPSP1, marking a decline in STF. Nonetheless, at 20° C (and even at 15° C), single‐shock CA3 stimulation still evoked action potentials (population spikes) in CA1 neurons, showing that, despite a loss in facilitation, the circuit continued to relay signals from CA3 to CA1 neurons. Taken together, our data are consistent with the proposal that awake and behaving hamsters have a dual feed‐forward neural circuit supporting STF, as in non‐hibernating mammalian species, but when the hamsters are hibernating, STF is muted.

Design of Dual Mode Power Supply Distribution Circuit with Detection and Control Functions

Design of Dual Mode Power Supply Distribution Circuit with Detection and Control Functions

Dual catalytic DNA circuit-induced gold nanoparticle aggregation: An enzyme-free and colorimetric strategy for amplified detection of nucleic acids

An enzyme-free dual catalytic DNA circuit for amplified detection of nucleic acids has been developed. The system functions based on a cyclic self-assembly of two auxiliary hairpins (H1 and H2) and three biotinylated hairpin oligonucleotides (H3, H4 and H5), in the format of two molecular circuits. In the upstream circuit, a target initiator (I) besides H1 and H2 hairpins constructs H1-H2 duplexes that trigger the operation of a subsequent circuit. In the downstream circuit, the H1-H2 duplex initiates cascaded self-assembly reactions, produces triplex H3-H4-H5, as sensing system, and releases the H1-H2 duplex as the catalyst for the self-assembly of additional hairpins. The H3-H4-H5 triplex acts as the scaffolds for assembling and orienting the streptavidin-functionalized gold nanoparticles (SA-AuNPs) into a lattice-like arrangement that generates a DNA-SA-AuNP cross-linked network, resulting in a dramatic pale red-to-blue color change. By ingeniously engaging two catalytic circuits with feedback amplification capabilities, the system can detect the target nucleic acid with an LOD value of 5 femtomolar and unambiguously discriminate spurious targets (i.e. targets containing substitution, insertion, and deletion nucleotides) without instrumentation. Simple and convenient operation of the assay makes the DNA circuit appropriate for point-of-care monitoring in resource-constrained settings.

A Dual-Resonator Temperature Sensing Approach With Time Base Error Suppression

In this study we present a novel dual-resonator temperature sensor which can be embedded in other MEMS sensors for improved thermal compensation and on-the-run calibration. For accurate temperature measurements, the proposed method mitigates time base errors in frequency counting, eliminates the need for a highly accurate reference clock and can cancel out the effects of aging of the time base without using a calibration process. The sensor structure is composed of a strain amplifying beam and two Double Ended Tuning Fork (DETF) resonators with different temperature sensitivities. The DETFs are kept at resonance simultaneously with a dual PLL circuit. Experiments reveal that at the expense of decreasing sensitivity, one can suppress the measurement errors which can be as high as 0.164 °C for the long resonator and 0.240 °C for the short resonator when a time base of 50 ppm accuracy is used. Moreover, while the frequency stability characteristics of the single sensing elements deteriorate drastically as the accuracy of the time base decreases, the frequency stability of the proposed frequency ratio remains unaffected and it is superior compared to both of the resonators.

Fugitive Aerosol Therapy Emissions during Mechanical Ventilation: In Vitro Assessment of the Effect of Tidal Volume and Use of Protective Filters

ABSTRACT Background: During mechanical ventilation of a patient requiring ventilatory support, bystanders could potentially be exposed to aerosolised drug. Methods: Fugitive drug aerosol emissions during simulated adult mechanical ventilation was assessed on a dual limb circuit. Tidal volume was set at 270 mL and 820 mL. The use of a protective filter on the exhalation port of the mechanical ventilator was assessed. Results: Higher fugitive aerosol mass concentrations in the local environment were associated with larger tidal volume (0.077 (0.073, 0.091) mg m–3 at Vt = 820 mL vs. 0.062 (0.056, 0.065) mg m–3 at Vt = 270 mL) when no protective filter was used. The range of mass median aerodynamic diameters recorded was from 0.93 to 2.96 µm. When a filter was placed on the exhalation port of the mechanical ventilator, no fugitive emissions were recorded. Conclusion: This study confirms that an appropriate filtration protocol mitigates the risk of fugitive emissions being released when patients undergo aerosol therapy during mechanical ventilation. A larger tidal volume resulted in higher fugitive aerosol mass.

Dynamic vibration absorber for shaft machining

The article is concerned with a new method that minimizes the vibration level of non-rigid axisymmetric parts on lathes. A schematic diagram of the vibration absorber control path is given. Its configuration is changing due to fictitious elastic stiffness parameters, as well as damping and the part–support subsystem weight. A functional dual circuit diagram of an automatic vibration level control system for non-rigid shafts machining is presented and its working principle is described

Different Control Strategies Adopted by Dual Inverter Fed Open End Winding Induction Motor Drive

An open end winding induction motor (OEWIM) drive fed by dual inverter is now being studied for high power application. It is simple in design, operation and it does not have any capacitor balancing issues. A dual inverter circuit can either have an isolated dc sources or a single dc source. Different PWM methods are used to control dual inverter fed OEWIM drive. A review of different control strategies applied for dual inverter fed OEWIM drives are given in this paper.

RANCANG BANGUN SISTEM REM MOBIL LISTRIK FUSENA

The brake system is a device to slow down or stop the movement of the wheel automatically so that the vehicle will move slowly. This completeness in the vehicle is very important and vital because it functions as a safety for life in driving. In the process of making the Electric Car Fusena brake system has steps in the process, consists of size planning, materials used, designs realized, manufacturing brake system supporting components, assembly, installation and testing of brake systems. The Fusena Electric Car brake system use a disc-type hydraulic brake system with one brake master that can work simultaneous with dual circuit fluids (front and rear braking). The comparison of the brake pedal is changed to 3: 1, designing and recreating the caliper stand to make it more precise so that it gets maximum brake performance and is better than the system used before. Static testing of the Fusena Electric Car hydraulic brake system is done by positioning the vehicle on an inclined plane at a slope of 15 and 20 with a variable driver load of 40 kg, 50 kg, 60 kg and 70 kg. The test results are that the vehicle does not experience displacement or movement. And the results of the average dynamic test of the Brake System at a speed of 27.3 km/h with an average braking distance of 171 cm = 1.71 meters and the average deceleration time is 0.26 seconds.

Shifting the boiler units of mining enterprises and processing plants to a new scheme of heat supply

This article analyzes the current situation in the heating circuit of the boiler room. Nowadays the Taiginsky enterprise proposes to modernize the heat supply system. For the first time, the dual circuit scheme is applied instead of a three circuit scheme. The scheme was developed instead of the existing boiler room scheme. There is also a description of the main equipment of the boiler. A hydraulic calculation was performed and a piezometric graph of the existing and proposed schemes was built. In addition, there is the heat calculation of fire-tube boiler and calculated technological losses during the transfer of heat energy to consumers. The calculation of the main technical and economic indicators is given in the economic part. The protection system of boiler units from mechanical and chemical influences is considered.

Design impacts of delay invariant high‐speed clock delayed dual keeper domino circuit

Precise keeper control of domino logic circuit can significantly increase the speed of operation. However, the positive feedback gain associated with the feedback keeper circuit unduly increases the delay variability. Here, a novel high-speed clock delayed dual keeper (CDDK) domino circuit is presented, which aims at reducing the delay and lower the impact of loop gain on delay variability. In CDDK domino structure, the keeper circuit comprising of two keeper devices is disabled during the initial evaluation phase. This significantly reduces the contention current and thereby the operating speed of the circuit is enhanced. The simulations of the circuits have been carried out for various metrics and the results have been analysed. Furthermore, the Monte-Carlo simulations carried out for 2000 runs on a 128-input OR gate using CDDK structure demonstrate reduced delay variability characteristics due to smaller loop gain of the CDDK domino structure against the conventional domino logic style. The enhanced speed of operation due to reduced contention current is demonstrated. The results are validated through comparison against the conventional domino logic counterpart circuits. The analyses of the circuits are performed using industry standard full-suite Cadence® tools using 90 nm technology library.

ŠILUMNEŠIO DEBITO ĮTAKOS FAZINIO VIRSMO MEDŽIAGOS VEIKIMUI TYRIMAS / INVESTIGATION OF THE INFLUENCE OF MASS FLOW RATE ON PHASE CHANGE MATERIAL BEHAVIOUR

The paper presents an experimental study of the influence of heat transfer fluid (HTF) mass flow rate on phase change materials (PCM) behaviour. The experimental study was performed on a specially designed test bench. Research object – PCM based thermal energy storage unit which consists of a stainless steel tank with dual circuit tube-fin copper heat exchanger. The tank (storage volume) was filled with phase change material RT82. The experiment was carried out using three different mass flow rates of HTF: high – 0.25 kg/s, medium – 0.125 kg/s, low – 0.05 kg/s. The analysis showed that in the case of high and medium mass flow rates the melting/solidification process highly depends on the temperature of inlet HTF. Influence of mass flow rate is higher in the case of low mass flow rate.

13.2: Equalizer and Clock/Data Recovery Circuits in SDICs for Intra‐Panel Interface

This work presents a front‐end circuits including of the equalizer and clock/data recovery (CDR) circuits in the source driver ICs (SDICs) for the TFT‐LCD intra‐panel interfaces. For 4K2K LCD TV, the data rate of SDICs has been increased to 5Gbps per lane, so it is a challenge to develop the front‐end circuits when they suffered from the serious ISI and large jitters in received data. In the front‐end circuits meeting the BOE’s CHPI specification, a cascade equalizer are used to widen the eye diagram to reduce BER and a dual loop CDR circuits are used to tolerate the large input jitter and power noise.

Thermal analysis on optimizing the capillary tube length of a milk chiller using DC compressor operated with HFC-134a and environment-friendly HC-600a refrigerants

In this work, the thermal analysis on optimizing the capillary tube lengths of a dual circuit refrigeration system was carried out experimentally. Two refrigeration circuits were individually operated using two DC powered compressors (HFC-134a and HC-600a) instead of conventional AC powered compressors. The capillary tube optimization was done to maximize the coefficient of performance and exergy efficiency. From the results, it was found that the power consumption and the refrigerant mass flow rate decreases with the increase of capillary tube length for both the HFC-134a and HC-600a circuits, while the refrigeration capacity and coefficient of performance increased up to the capillary tube length of 4.57 m and then decreased. The maximum refrigeration capacity, ice formed, power consumption, and coefficient of performance experienced in the HC-600a circuit were 9.65%, 19.03%, 3.53%, and 7.34% lower than those of the HFC-134a circuit at the optimum capillary tube length. It was also found that at the optimum capillary length, the COP was maximum for the HFC-134a circuit while the exergy efficiency was maximum for the HC-600a circuit. The exergy efficiency of the HC-600a circuit was 11.13% higher than that of the HFC-134a circuit. At the optimum capillary tube length, the total equivalent warming impact values of the HFC-134a and HC-600a circuits were 961.13 kg CO2-eq and 785.77 kg CO2-eq, respectively.

Securing the AES Cryptographic Circuit Against Both Power and Fault Attacks

Aiming to protect cryptographic circuits against physical attacks, researchers have proposed a variety of mature and effective countermeasures. However, most of these defensive technologies are used for specific and single attack, thus it is hard to thwart combined attack, such as combined power and fault attacks. In this paper, we propose a dual complementary infection countermeasure for Advanced Encryption Standard (AES) cryptographic circuit to defend against both power and fault attacks. According to the target AES circuit, we first design and construct a dual complementary AES circuit to defend against power attacks, which can balance the power consumption when processing different data. Besides, to defend against fault attacks, in the dual complementary AES circuit, we design an improved random infection mechanism to diffuse the effect of injected faults. Experiment results show that the proposed countermeasure can thwart both power and fault attacks effectively. Compared with those AES circuits which can only defend against single attack, our designed circuit increases greatly the security under extra 83.1% area overhead and 2.1% impacts on the maximum working frequency.

A Simple Unified Model for Generic Operation of Dual Active Bridge Converter

This paper presents a simple and generic model of a dual active bridge converter valid throughout its range of operation. It is suitable for all operating modes and modulation strategies such as phase-shift, extended phase-shift, dual phase-shift, or triple phase-shift modulation. It hypothesizes that any mode of its operation characterized by the duty ratios ( $d_1$ , $d_2$ ) of the two full-bridge converter ac voltages and the phase shift ( $\phi$ ) between them can be decomposed into four parallel dual active bridge circuits operating in simple phase-shift modulation. The hypothesis is proven mathematically; the average and small-signal models are derived and validated through simulations and experiments on a hardware prototype.

Common-Mode Current Suppression of Transformerless Nested Five-Level Converter With Zero Common-Mode Vectors

Three-phase transformerless multilevel converters are widely used in the high-voltage photovoltaic power generation systems because of their low total harmonic distortion, high power density, and high conversion efficiency. One three-level flying capacitor converter and dual T-type three-level circuits can be combined to derive the compact and cost-effective nested five-level converter. However, due to the lack of an isolation transformer, the common-mode current is generated to degrade the converter performance. First, the common-mode equivalent circuit model of the nested five-level converter is initially derived to further explore its common-mode current generation mechanism. Then, the zero common-mode space vector modulation (ZCM-SVM) is proposed to reduce the common-mode current, which chooses the specific zero common-mode voltage space vectors to synthesize the reference vector. Then, an advanced coordinate transformation is introduced to realize the flexible sector selection and reduce the complexity of the vector action time calculation. The proposed modulation achieves the common-mode current suppression with high dc bus voltage utilization. Finally, the effectiveness of the proposed ZCM-SVM strategy is verified by simulation and experimental results.

The Starch Is (Not) Just Another Brick in the Wall: The Primary Metabolism of Sugars During Banana Ripening.

The monocot banana fruit is one of the most important crops worldwide. As a typical climacteric fruit, the harvest of commercial bananas usually occurs when the fruit is physiologically mature but unripe. The universal treatment of green bananas with ethylene or ethylene-releasing compounds in order to accelerate and standardize the ripening of a bunch of bananas mimics natural maturation after increasing the exogenous production of ethylene. The trigger of autocatalytic ethylene production regulated by a dual positive feedback loop circuit derived from a NAC gene and three MADS genes results in metabolic processes that induce changes in the primary metabolism of bananas. These changes include pulp softening and sweetening which are sensorial attributes that determine banana postharvest quality. During fruit development, bananas accumulate large amounts of starch (between 15 and 35% w/w of their fresh weight, depending on the cultivar). Pulp softening and sweetening during banana ripening are attributed not only to changes in the activities of cell wall hydrolases but also to starch-to-sugar metabolism. Therefore, starch granule erosion and disassembling are key events that lead bananas to reach their optimal postharvest quality. The knowledge of the mechanisms that regulate sugar primary metabolism during banana ripening is fundamental to reduce postharvest losses and improve final product quality, though. Recent studies have shown that ethylene-mediated regulation of starch-degrading enzymes at transcriptional and translational levels is crucial for sugar metabolism in banana ripening. Furthermore, the crosstalk between ethylene and other hormones including indole-3-acetic acid and abscisic acid also influences primary sugar metabolism. In this review, we will describe the state-of-the-art sugar primary metabolism in bananas and discuss the recent findings that shed light on the understanding of the molecular mechanisms involved in the regulation of this metabolism during fruit ripening.