Maximum Input Research Articles

Suppression of Modulation Instability Induced Phase Noise in the Long-Haul Phase-Sensitive Optical Time Domain Reflectometry.

Modulation instability (MI) is the main limitation factor of the maximum optical power in long-haul phase-sensitive optical time domain reflectometry (Φ-OTDR), and induces signal fading and serious phase noise. In this paper, a method of coherent seed injection is proposed to suppress the MI-induced phase noise in long-haul Φ-OTDR. The spontaneous MI is suppressed by stimulating induced MI in an optical fiber. The visibility of the signal in Φ-OTDR is enhanced and the phase noise is suppressed significantly. This paper offers an effective method to increase the maximum input power with the MI-induced phase noise suppressed in the long-haul Φ-OTDR system. As a result, the maximum input power and sensing distance can be potentially increased, which is greatly beneficial to the enhancement of the performance of long-haul Φ-OTDR.

The potential for hydrogen ironmaking in New Zealand

Globally, iron and steel production is responsible for approximately 6.3% of global man-made carbon dioxide emissions, because coal is used as both the combustion fuel and chemical reductant. Hydrogen reduction of iron ore offers a potential alternative ‘near-zero-CO2’ route, if renewable electrical power is used for both hydrogen electrolysis and reactor heating. This paper discusses key technoeconomic considerations for establishing a hydrogen direct reduced iron (H2-DRI) plant in New Zealand. The location and availability of firm renewable electricity generation is described, the experimental feasibility of reducing locally-sourced titanomagnetite ironsand in hydrogen is shown, and a high-level process flow diagram for a counter-flow electrically heated H2-DRI process is developed. The minimum hydrogen composition of the reactor off-gas is 46%, necessitating the inclusion of a hydrogen recycle loop to maximise chemical utilisation of hydrogen and minimize costs. A total electrical energy requirement of 3.24 MWh per tonne of H2-DRI is obtained for the base-case process considered here. Overall, a maximum input electricity cost of no more than US$80 per MWh at the plant is required to be cost-competitive with existing carbothermic DRI processes. Production cost savings could be achieved through realistic future improvements in electrolyser efficiency (∼ US$5 per tonne of H2-DRI) and heat exchanger (∼US$3 per tonne). We conclude that commercial H2-DRI production in New Zealand is entirely feasible, but will ultimately depend upon the price paid for firm electrical power at the plant.

Alternatives to rice-wheat cropping system under partially reclaimed sodic soils

A field experiment was conducted during 2013-14 to 2015-16 at Central Soil Salinity Research Institute, Regional Research Station, Lucknow to find out the alternate to rice (Oryza sativa L.)- wheat (Triticum aestivum L.) cropping system under partially reclaimed sodic soils. Four cropping systems, viz. rice (Oryza sativa L.)- wheat (Triticum aestivum L.), sorghum (Sorghum bicolor)-berseem (Trifolium alexandrinum), sweet basil (tulsi) (Ocimum basilicum L.)-matricaria (Matricaria chamomilla) and chilli (Capsicum spp.)-garlic (Allium sativum) were evaluated in the light of sustainability, potentiality and profitability. Maximum rice equivalent yield (14.21 t/ha) and production efficiency (61.25 kg/ha/day) were recorded with sweet basil-matricaria cropping system whereas, highest land use efficiency (78.35%) was observed under sorghum-berseem fodder based cropping system. Highest water use efficiency (150.72 kg/ha cm) was recorded with chilli-garlic cropping system followed by sweet basil-matricaria, but the total amount of water used was more (125.65 cm) in rice-wheat system. The water requirements of sorghum-berseem, sweet basilmatricaria and chilli -garlic cropping systems were 8.0, 19.8 and 31.8% less than the rice-wheat cropping system. Among the cropping systems evaluated, maximum energy input (27.50 MJ/ ha) and output (314.46 MJ/ha) were analyzed in rice-wheat system. Whereas, maximum energy use efficiency (11.99) was found with sweet basil- matricaria followed by sorghum-berseem (11.91) cropping systems. Highest soil ameliorative potential was established with sweet basil -matricaria cropping system than rest of the cropping systems. Highest net return (₹ 63222/ha) and benefit: cost ratio of 2.74 was deliberated with medicinal and aromatic crop based sweet basil-matricaria cropping system.

A Modeling Study of the Seasonal, Latitudinal, and Temporal Distribution of the Meteoroid Mass Input at Mars: Constraining the Deposition of Meteoric Ablated Metals in the Upper Atmosphere

This study provides a comprehensive description of the deposition of meteor-ablated metals in the upper atmosphere of Mars, accounting for the temporal, vertical, latitudinal, and seasonal distribution. For this purpose, the Leeds Chemical Ablation Model is combined with a meteoroid input function to characterize the size and velocity distributions of three distinctive meteoroid populations around Mars—the Jupiter-family comets (JFCs), main-belt asteroids, and Halley-type comets (HTCs). These modeling results show a significant midnight-to-noon enhancement of the total mass influx because of the orbital dynamics of Mars, with meteoroid impacts preferentially distributed around the equator for particles with diameters below 2000 μm. The maximum total mass input occurs between the northern winter and the first crossing of the ecliptic plane with 2.30 tons sol−1, with the JFCs being the main contributor to the overall influx with up to 56% around Mars’ equator. Similarly, total ablated atoms mainly arise from the HTCs with a maximum injection rate of 0.71 tons sol−1 spanning from perihelion to the northern winter. In contrast, the minimum mass and ablated inputs occur between the maximum vertical distance above the ecliptic plane and aphelion with 1.50 and 0.42 tons sol−1, respectively. Meteoric ablation occurs approximately in the range altitude between 100 and 60 km with a strong midnight-to-noon enhancement at equatorial latitudes. The eccentricity and the inclination of Mars’ orbit produces a significant shift of the ablation peak altitude at high latitudes as Mars moves toward, or away, from the northern/southern solstices.

Development of High-Power Charge Pump Rectifier for Microwave Wireless Power Transmission

This study theoretically and experimentally indicates that a charge pump rectifier for low-power rectifiers such as RF-ID can be applied to high-power rectifiers and can attain the same level of RF-dc conversion efficiency and twice as high power rectification as the single-shunt rectifiers. A high-power rectifier is primarily a single-shunt rectifier, and a charge pump rectifier that applies twice the output voltage is used in low-power applications such as RF-ID. We aim to enhance the power of charge pump rectifiers by focusing on their characteristics. A fabricated 5.8 GHz charge pump rectifier achieved an RF-dc conversion efficiency of 70.8% at an input power of 8.0 W and a load resistance of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$150\,\Omega$</tex-math></inline-formula> . This result is also the highest efficiency for 39 dBm rectifiers in the 5.8 GHz band. Compared to a single-shunt rectifier with the same diode, the charge pump rectifier generated twice the input power and efficiency difference of 2.9% at the maximum input power. These results indicate that the charge pump rectifier has an advantage over the single-shunt rectifier in high-power rectifiers.

A 5.8-GHz Rectifier Using Diode-Connected MESFET for Space Solar Power Satellite System

To improve the power handling capability at ground stations of a 5.8-GHz solar space power satellite using microwave power transmission, a power charge-pump meta-semiconductor field-effect transistor (MESFET)-based rectifier is presented in this article. Unlike conventional microwave Schottky diodes, diode-connected MESFETs, whose nonlinear characteristics help them to have a unique current–voltage (I-V) curve that overcomes the limitations of a Schottky diode. Thus, the maximum input power of the proposed rectifier is extended up to 251.2 mW by replacing a Schottky diode with a diode-connected MESFET. Additionally, a class F harmonic processing network is introduced to control the voltage and current waveform at the load of the rectifier. Consequently, the RF-dc conversion efficiency is increased since the power dissipation is limited at the junction resistance of both the drain and the source of the MESFET. Owing to the abnormal characteristics of the diode-connected MESFET, the measured conversion efficiency of our rectifier is approximately 73.2% at 126 mW, and the input power range for rectifier efficiency higher than 50% is between 16 and 224 mW. The proposed rectifier for the space solar power satellite application is demonstrated and verified using a microwave wireless power transmission system.

Withdrawal: P. A. Harsha Vardhini and M. Makkena (2022), Design and Comparative Analysis of On‐Chip Sigma Delta ADC for Signal Processing Applications. Advanced Control for Applications: Engineering and Industrial Systems. Accepted Author Manuscript e82. https://doi.org/10.1002/adc2.82

Advent in VLSI technology made digital signal processing to take over analog signal processing. Analog to digital converter plays a vital role in modern digital processing applications. Sigma delta analog to digital converter architecture being digital dominant architecture is much suitable for signal processing applications. This paper presents the design of a low pass continuous time sigma delta analog to digital converter on-chip architecture suitable for signal processing applications with a very few passive components connected externally to FPGA. Schematic level architecture of high-speed comparator working at a differential swing which is not allowed by standard differential pads is designed. By applying various differential swings at the input to LVPECL, the performance and power is analyzed. High performance comparator schematic is designed for On-chip Continuous-time Sigma-delta ADC architecture. Simulations are carried out to verify the maximum input frequency for given RC values. Xilinx provided Spartan 6 I/O pad and package SPICE models are used. Power analysis is carried out with LVPECL logic family based differential buffers along with external RC circuit. The analog and digital sections simulations along with mixed signal simulations at different stages are performed. Power and performance analysis are carried out using H-Spice and Questasim simulations.

DC-Link voltage control of a multifunctional PV-GCVSI to reduce VSI switching losses

ABSTRACT The reference input dc voltage of grid connected voltage source inverter (GCVSI) is altered in this article based on power (both active and reactive) injection from GCVSI for minimising inverter switching losses, and total harmonic distortion (THD) of grid current. If the GCVSI is exclusively used for actual power injection from the photo-voltaic (PV) system to the utility grid, the needed input dc voltage of GCVSI is twice the utility grid phase peak voltage. According to the literature, GCVSI is also used to compensate for power quality issues, and in these circumstances, the dc-link voltage value is determined by the maximum power injection of GCVSI. Under reduced load, and reduced power generation from the PV system, keeping maximum GCVSI input dc voltage reference causes extra voltage stress at GCVSI switches, and the grid current THD is worse due to high ripple current in filter inductance. Therefore, to reduce the inverter switching losses and to improve the grid current THD, the relationship between the GCVSI input dc voltage reference and the power flow from GCVSI has been formulated. The proposed work is verified using simulation studies, as well as hardware studies, and the results are compared with existing methods for validation.

Jaw mechanics in macrophagous lamniform sharks and their evolutionary and functional implications.

Jaw mechanics of lamniform sharks were examined three-dimensionally to analyze the variability in jaw shape and the evolution of the jaw system based on the extant macrophagous species. Three-dimensional lever analysis was applied to lamniform jaws to calculate bite force at each tooth relative to maximum input force from jaw adductor muscles for interspecific comparison of efficiency in lamniform jaws. When total input force from the jaw adductor muscles on both working and balancing sides of the skull is considered, input force varies along the jaw because the contribution by balancing side muscles is not constant. The phylogenetically basal-most species, Mitsukurina owstoni, has the least efficient jaws due to posteriorly positioned jaw adductor muscles. Our study shows that the higher efficiency of jaws is regarded as apomorphic in lamniform phylogeny owing to the anterior extension of jaw adductor muscles relative to M. owstoni and a relative decrease in jaw length in relation to width seen in some species, both of which increase leverage. Differences in the efficiency of jaws among derived genera or species are due to the morphology of their jaws. The relationship between calculated bite force relative to maximum input force and tooth morphology indicates low relative bite forces being exerted at anteriorly located, narrow, piercing teeth, whereas high relative bite forces at posteriorly located, broad, cutting, or crushing-type teeth. As a result, the biting pressure during feeding is maintained throughout the tooth series.

Robust Distributed Noise Suppression in Acoustic Sensor Networks

In acoustic sensor networks (ASNs), speech-related applications often perform poorly due to serious noise interference. To address this problem, a robust distributed noise suppression method for ASNs is proposed in this article. Specifically, by using the maximum input signal-to-noise ratio (SNR) subarray as the reference array, the robust distributed parameterized multichannel Wiener filter (RD-PMWF) is proposed for a tradeoff between the desired signal distortion and the noise suppression in the fully connected ASNs, where each subarray fuses its multiple speech signals into a single-channel signal by a compression vector. Then, to seek out the maximum input SNR subarray in any topology, an in-network compare method that takes place on the tree topology is presented based on a data-driven signal flow. Finally, the RD-PMWF without topology constraints is obtained, relying on the in-network comparison of input SNR, and the communication cost and computational complexity are analyzed. The proposed method is robust to the change of network topology and speaker positions even at low input SNR situations and successfully suppresses noise by using only the subarray with the maximum input SNR and its neighbors in any topology. Simulation and real-world experimental results illustrate that the proposed method achieves good noise suppression performance in noisy and reverberant ASNs while exhibiting an even lower computational complexity.

Modelling and Performance Analysis of Cyclic Hydro-Pneumatic Energy Storage System Considering the Thermodynamic Characteristics

The energy storage system of electric-drive heavy mining trucks takes on a critical significance in the characteristics including excellent load capacity, economy, and high efficiency. However, the existing battery-based system does not apply to harsh cold environments, which is the common working condition for the above trucks. A type of cycle hydro-pneumatic energy storage system for the trucks was proposed in this study. The dynamic model of the system, including the dynamic and thermodynamic models of hydraulic and pneumatic parts, was built to analyze the performance of the system. Subsequently, the thermodynamic characteristics were clarified during the energy storage and released through the real test condition-based simulation. The power and energy performances of the system were studied in practice based on the above characteristics. The analysis of the results showed that the system reduced 22.03% driving power at the optimal braking energy recovery rate, the energy density was nearly 12.6 MJ/m3, the maximum input power was higher than 230 kW, and the cycle efficiency was about 40.6%. The results of this study will be conducive to the application of the hydro-pneumatic energy storage system for the electric-drive mining trucks and reducing the resulting carbon emission.

Direct thrust test and asymmetric performance of porous ionic liquid electrospray thruster

In order to meet the demand of CubeSats for low power and high-performance micro-propulsion system, a porous ionic liquid electrospray thruster prototype is developed in this study. 10 × 10 conical emitter arrays are fabricated on an area of 3.24 cm2 by computer numerical control machining technology. The propellant is 1-ethyl-3-methylimidazolium tetrafluoroborate. The overall dimension of the assembled prototype is 3 cm × 3 cm × 1 cm, with a total weight of about 15 g (with propellant). The performance of this prototype is tested under vacuum. The results show that it can work in the voltage range of ±2.0 kV to ±3.0 kV, and the maximum emission current and input power are about 355 μA and 1.12 W. Time of Flight (TOF) mass spectrometry results show that cationic monomers and dimers dominate the beam in positive mode, while a higher proportion of higher-order solvated ion clusters in negative mode. The maximum specific impulse is 2992 s in positive mode and 849 s in negative mode. The thrust is measured in two methods: one is calculated by TOF results and the other is directly measured by high-precision torsional thrust stand. The thrust (T) obtained by these two methods conforms to a certain scaling law with respect to the emission current (Iem) and the applied voltage (Vapp), following the scale of T ∼ IemVapp0.5, and the thrust range is from 2.1 μN to 42.6 μN. Many thruster performance parameters are significantly different in positive and negative modes. We speculate that due to the higher solvation energy of the anion, more solvated ion clusters are formed rather than pure ions under the same electric field. It may help to improve thruster performance if porous materials with smaller pore sizes are used as reservoirs. Although there are still many problems, most of the performance parameters of ILET-3 are good, which can theoretically meet the requirements of CubeSats for micro-propulsion system.

High-Efficiency D-Band Monolithically Integrated GaN SBD-Based Frequency Doubler With High Power Handling Capability

A high-efficiency <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${D}$ </tex-math></inline-formula> -band monolithically integrated GaN frequency doubler based on a pair of antiseries four-anode planar GaN Schottky barrier diodes (SBDs) has been successfully fabricated. Unlike the traditional hybrid integrated circuit technology, the monolithic integrated circuit technology has been used in the design and fabrication of GaN SBD-based frequency doubler circuits to achieve good alignment and low conversion losses. At room temperature, the experiments show that the peak conversion efficiency reaches 17.0% at 115.6 GHz under a continuous wave (CW) driving which is a critical requirement for many practical applications. The efficiency of 17.0% is the highest efficiency of GaN SBD-based multipliers at present under CW driving mode. This monolithically integrated doubler also exhibits a broadband high efficiency characteristic of more than 4.7% (−5.58 dB from 17%) across a 10% band from 109 to 121 GHz. In addition, high CW power handling capability of the proposed frequency doubler is verified. The experiments show that the frequency doubler can endure a maximum CW input power of 0.5 W.

Design of High Step-Down Ratio Isolated Three-Level Half-Bridge DC–DC Converter With Balanced Voltage on Flying Capacitor

A high step-down ratio three-level half-bridge (TLHB) dc–dc converter with a current-doubler rectifier is presented for power conversion from a 48-to-60-V input to a 0.5-to-1-V output. The proposed TLHB topology and operation employed on the primary side improve the power-conversion efficiency by reducing the switching loss while minimizing the turn ratio of the transformer by converting the input voltage down to one quarter on the primary side. Moreover, it reduces the voltage stress on switches by half, thereby enabling the converter to be implemented with Si transistors with low breakdown voltage. The designed TLHB gate-driver IC minimizes the delay mismatches in gate drivers and mitigates the effect of the leakage inductance of the transformer, reducing the voltage imbalance on the flying capacitor without any balancing scheme in the controller. The proposed dc–dc converter implemented with 40-V Si transistors for the primary-side switches achieves 92.8% peak efficiency while supporting the maximum load current of 60 A and the maximum input voltage of 60 V. The converter with the proposed TLHB gate driver IC shows less than 0.8% voltage imbalance on the flying capacitor.

High Gain, Low Noise, Low Voltage, and Low Power Current Mode Up-Conversion Mixer for 5G Applications

A high conversion gain, low noise up-conversion mixer for 5G New Radio band (850 MHz) Internet of Thing (IoT) applications implemented in UMC 0.18 μm standard CMOS technology is presented. The proposed mixer is based on the Flipped voltage follower current mirror with a passive switching circuit. The proposed up-conversion mixer achieves a noise figure (NF) of 4.4 dB, maximum Conversion Gain (CG) of 33.85 dB, maximum input third-order intercept point (IIP3) of 33.16 dBm, and output third-order intercept point (OIP3) of 11.89 dBm. It has a total power consumption of 23.58 mW with a 1.2 V supply voltage. The overall chip area of the design is 26.5 µm × 54.9 µm.

Reconfigurable flexible inverted-F antenna for wireless capsule endoscopy

In this study, a reconfigurable conformal antenna suitable for Wireless Capsule Endoscopy (WCE) is proposed. The proposed antenna achieves reconfigurable omnidirectional radiation regardless of its orientation and position inside the Gastrointestinal (GI) tract. The reconfigurable omnidirectional radiation pattern is obtained using two PIN diodes, which provide four stats, and with the aid of a microcontroller inside the capsule, a decision can be made to decide which state gives the higher gain simultaneously. The capsule antenna is designed as a meandered Inverted-F antenna (IFA) operating at 433 MHz on Rogers 5880 laminate and attains a volume of 30 × 15 × 0.254 mm3 in planar form, and the conformal form fits inside a capsule with a length of 26 mm and a diameter of 12 mm. The proposed capsule antenna is simulated in muscle, stomach, and colon homogenous boxes in different orientations. It achieves a realized gain of −33.64 dBi inside a colon cube of length 100 mm. The proposed antenna is then tested inside a voxel model. Moreover, the robustness of the communication system containing the capsule antenna is satisfied. When the maximum input power (11 mW) is calculated from the Specific Absorption Ratio (SAR) in the colon, the link Carrier-to-Noise ratio (C/No) is higher than the required C/No for 4 Mbps data rate and at distances up to 3 m. The proposed capsule antenna’s performance is validated by fabrication and measuring it inside a muscle phantom.

Design and implementation of zeta converter for LED driver applications

The objective of this study is to analyze the design and operation of low power, stand-alone active led driver applications. The system is powered by solar PV panels with a maximum input power of 125 W. The chosen converter supports continuous conduction mode. The device seems to have a switching frequency of 20 kHz. The duty cycle of a converter is controlled by the MPPT controller, which keeps the dc bus voltage constant. MPPT employs an incremental conductance method. The intention of this converter used to control the voltage at 48 V. The preferred converter is verified in both Matlab/Simulink and its performance is evaluated on hardware prototype of 25 W. While PV module efficiency is low and power output is dependent on solar irradiation and ambient temperature, maximizing power output while increasing efficiency is of key significance. The resulting system is highly efficient, low cost and able to track power faster.

Fast Diesel Aftertreatment Heat-Up Using CDA and an Electrical Heater Between 1.2 and 5.0 kW

Commercial vehicles require fast aftertreatment heat-up in order to move the selective catalytic reduction catalyst into the most efficient temperature range to meet upcoming NOX regulations while minimizing CO2. This study is a follow-up study using an electric heater upstream of a LO-SCR followed by a primary aftertreatment system having an engine equipped with cylinder deactivation. The focus of this study is to minimize the maximum power input to the e-heater without compromising tailpipe NOX and CO2. A system solution is demonstrated using a heavy-duty diesel engine with an end-of-life aged aftertreatment system targeted for 2027 emission levels using various levels of controls. The baseline layer of controls includes cylinder deactivation to raise the exhaust temperature more than 100°C in combination with elevated idle speed to increase the exhaust mass flow rate through the aftertreatment system. The engine load is adjusted to compensate for generating electrical power on the engine. The combination of electrical heat, added load, cylinder deactivation, and elevated idle speed allows the aftertreatment system to heat up in a small fraction of the time required by today’s systems. This work was quantified over the cold federal test procedure, hot FTP, low load cycle (LLC), and the U.S. beverage cycle showing improved NOX and CO2 emissions. The improvement in NOX reduction and the CO2 savings over these cycles are highlighted.

A 4-channel front-end electronics for muon drift tubes detectors in 65 nm CMOS technology

A 4-channel front-end electronics chip in 65 nm CMOS technology (ASD65 nm) for muon drift tube chambers at high background counting rates in the ATLAS detector at High-Luminosity LHC and in future high-energy collider experiments is presented. Each channel of the ASD65 nm chip is a mixed-signal processing circuit consisting of a Charge Sensitive Preamplifier (CSP), a two-stage shaper, and a timing discriminator. The CSP exhibits a peaking time of 11 ns and a sensitivity of 1.1 mV/fC. The peaking time of the full analog chain is 14.6 ns. The minimum signal-to-noise ratio of the channel is 15 dB for the minimum input charge of 5 fC, and it rises to 40.5 dB for the maximum input charge of 100 fC. At the output, the time representation of input signal is provided in both, CMOS level as well as low-voltage-differential-signal. Each channel consumes a current of 10.6 mA from a single 1.2 V supply, and occupies an area of 0.235 mm2. The specified performance parameters of the ASD65 nm have been achieved for 60 pF parasitic capacitance of the detector connected the input terminal.

Mapping of cavitation intensity in a novel dual-frequency ultrasonic reactor of capacity 10 L

Mapping of a dual-frequency ultrasonic reactor was performed based on measurements of local cavitation intensity at various horizontal and vertical planes in the reactor for single frequency operation (22 kHz or 44 kHz) and dual-frequency operation (22 + 44 kHz) at varying input power of 250 and 450 W. The average cavitation intensity ranged between 73.6 and 86.7 W/cm2, 38.75 and 64.4 W/cm2, 86.7 and 100.6 W/cm2 for the operating frequencies of 22, 44 and 22 + 44 kHz respectively at maximum input power of 450 W depending on the location. Bubble dynamics simulations at various frequencies were also performed using the Keller-Miksis equation and the trends of bubble radius, collapse temperature and pressure were found to effectively match the experimental findings for cavitation intensity. The work has clearly elucidated the dependency of the cavitational activity on location, power dissipation and operating frequency mode with dual-frequency operating showing higher cavitation intensity.