Reduce System Size Research Articles

Enhancing the energy harvesting of micro-notched turbine for applications in low power devices

It is the future trend to energize small home appliances, medical devices, micro-devices, etc. through miniature generation. Micro-Notched turbine (MiNT) converts mechanical energy to electrical energy for portal devices. The current challenge is to harness the maximum energy by modifying its design, model, blade size, and casing. The MiNT presented in this research is one of the few specialized miniature harvesters with desirable characteristics and the potential to be optimized for maximum power generation. To reap maximum benefit from MiNT, the design of the turbine, the shape of the blades, and the tracking system were modified. Similarly, the size of the MiNT turbine was decreased, and its efficiency was enhanced. In this research, the particle swarm optimization algorithm and resistor emulation technique were employed to enhance Maximum Power Point Tracking (MPPT). Meanwhile, the converter efficiency was also observed. For the validation of results, the proposed technique was compared with passive MPPT and adaptive MPPT techniques. During the simulation, micro-notched-based energy collection devices with upgraded MPPT technology were used. By implementing this hybrid system, the maximum power point was accurately tracked, resulting in improved power output, reduced system size, and improved converter efficiency.

Design of an Underwater Acoustic Waveform and Integrated System for Communication and Detection

Combining underwater communication and detection can reduce system size and power consumption as well as improve secrecy. This paper presents a waveform that integrates continuous phase modulation (CPM) for data communication with linear frequency modulation (LFM) for detection. It is shown that the velocity ambiguity and range performance with this waveform are similar to those with only LFM. An integrated underwater acoustic system is also proposed to achieve simultaneous communication and detection. A symbol suffix (SS) is introduced into the signal frame at the transmitter and a two-step algorithm is employed at the receiver for frequency and phase offset estimation. Results are presented, showing that this decreases the sensitivity to CPM and reduces the range ambiguity side lobes. Further, the proposed system can effectively recover the data from the received signal. The bit error rate (BER) is shown to be better than that of traditional systems without a symbol suffix. With changes in the signal-to-noise ratio (SNR), the bit error rate (BER) in underwater acoustic environments is comparable to that in an additive white Gaussian noise (AWGN) channel, indicating a significant improvement in communication performance within the underwater acoustic channel.

The Emerging Silicon Carbide MOSFET for Medical Healthcare Applications

Silicon carbide (SiC) MOSFETs are transforming the design and functionality of medical devices by providing exceptional efficiency, reliability, and compactness. Despite standard silicon-based power devices, SiC MOSFETs offer enhanced electrical and thermal properties including higher breakdown voltage, lower switching losses, and improved thermal conductivity. In healthcare applications, whereby accuracy, energy efficiency, and reliability of operations are critical, these characteristics are extremely significant SiC MOSFETs give improved power densities and increased switching speeds in medical imaging systems such as CT and MRI scanners, hence improving image quality and reducing system size. The excellent efficiency of wearable and portable medical devices helps to downsize and extends battery lifetime. Furthermore, ensuring dependability in critical care settings, SiC MOSFETs increase the efficiency of instruments for surgery, diagnostic instruments, and lifesupport systems. The importance of SiC MOSFETs in improving healthcare technology is addressed in this article along with their main features relating healthcare, applications in the field, and their benefits to the healthcare system. SiC MOSFETs have the potential to become an essential element of advanced medical electronics as the healthcare industry progressively incorporates sophisticated and energy-intensive technologies, therefore enabling developments in both clinical and portable care solutions.

A novel eight-switch nine-level modified ANPC inverter topology and its optimal modulation strategy

An eight-switch nine-level modified ANPC inverter (8S-9L-MANPC) is designed and simulated in this paper. With this topology, only one DC voltage source and eight active semiconductor switches are required, significantly reducing system size, weight, and cost. The structure consists of a five-level ANPC inverter cascaded with a two-level leg converter. This arrangement extends the 5L-ANPC structure to a 9L configuration without requiring the use of additional capacitors. To maintain the balancing of the flying capacitor (FC), a modulation strategy using a switching state redundancy-based control method is employed. Recent 9L inverters incorporating flying capacitors and based on a hybrid structure have been compared with the proposed structure. By conducting this comparison, we can highlight the potential improvements offered by the proposed structure over the recent 9L inverters in terms of reduced component count, simplified design, and cost savings. The proposed 8S-9L-MANPC inverter is tested under various operating situations in MATLAB/Simulink simulation.

Novel design and implementation of 3d packaged wideband bandpass filters

This study presents an innovative method for designing a 3D packaged wideband bandpass filter (BPF) by vertically integrating a high-pass filter (HPF) and a low-pass filter (LPF) using an air cavity and vertical interconnect accesses (VIAs). This integration enhances performance while significantly reducing system size. The fabricated BPF, constructed on multilayer substrates, achieves a passband from 2.175 to 4.2 GHz with less than 2.5 dB insertion loss and a return loss exceeding 10 dB. The design utilizes a partial substrate integrated suspended line (SISL) structure, enabling precise control over the equivalent dielectric constant and characteristic impedance to optimize insertion loss. The height of the air cavity, determined through theoretical analysis and S-parameter inversion, is critical for achieving optimal filter performance. The methodology allows for independent circuit designs on each layer, resulting in a 3D assembly. This refined approach makes it easier to produce compact bandpass and multi-band filters, simplifying circuit development and enabling scalable fabrication. This design is versatile across different frequency ranges, demonstrating significant practical and theoretical benefits.

Heat transfer augmentation by using different techniques in small scale channels: A review study

In this paper highlights the most significant recent developments in scientific study on Heat sinks are thermal management components made of materials with sufficient thermal conductivity qualities. Due to the increase in operating power and speed as well as the general reduction in system size, the issues of heat removal and temperature management have taken on increasing importance in these studies. Changing the geometry of extended surfaces, the material from which they were made, the working fluid that ran over them and or the dimension of the channel, are some of the subcategories in which studies have been conducted. The current review addresses the main recent findings in the forced convection heat transfer happened at laminar flow inside small scale diameters channels. The recent studies indicated a remarkable enhancement with the change of Re, D and internal geometry of channel. The configuration of flow passages also adopted as a different passive technique to enhance thermal fluid flow.

Long-term mesoscale imaging of 3D intercellular dynamics across a mammalian organ

A comprehensive understanding of physio-pathological processes necessitates non-invasive intravital three-dimensional (3D) imaging over varying spatial and temporal scales. However, huge data throughput, optical heterogeneity, surface irregularity, and phototoxicity pose great challenges, leading to an inevitable trade-off between volume size, resolution, speed, sample health, and system complexity. Here, we introduce a compact real-time, ultra-large-scale, high-resolution 3D mesoscope (RUSH3D), achieving uniform resolutions of 2.6×2.6×6μm3 across a volume of 8,000×6,000×400μm3 at 20Hz with low phototoxicity. Through the integration of multiple computational imaging techniques, RUSH3D facilitates a 13-fold improvement in data throughput and an orders-of-magnitude reduction in system size and cost. With these advantages, we observed premovement neural activity and cross-day visual representational drift across the mouse cortex, the formation and progression of multiple germinal centers in mouse inguinal lymph nodes, and heterogeneous immune responses following traumatic brain injury-all at single-cell resolution, opening up a horizon for intravital mesoscale study of large-scale intercellular interactions at the organ level.

Integrated Controller for Fuel Cell Systems: A Full-loop Architecture

Abstract In response to the global initiative towards hydrogen energy, increasing focus has been placed on enhancing the performance, reliability and endurance of fuel cells by utilizing advanced control and monitoring strategies. However, due to the multi-variable. multi-loop and multi-physics nature of hydrogen fuel cells, the current decentralized architecture, where fuel cell controllers are isolated and placed in separate enclosures is no longer sufficient to carry out intricate coordinated control strategies. To this end, in this paper, we introduce a novel full-loop architecture, which enables the integration of the fuel cell controller, the air compressor controller, and the power electronics controller within one enclosure, reducing system size and cost. Moreover, based on the integrated hardware architecture, coordinated control such as oxygen/hydrogen pressure coordination can be carried out efficiently. A case study on electrochemical impedance spectroscopy has been conducted, demonstrating the advanced control and monitoring capabilities of this controller architecture.

The New Technology Solutions for Advanced SiP Devices

For many years, system-in-Package (SiP) technology has been a focus for semiconductor packaging to address the ongoing market trend of system integration and size reduction. Today’s increased complexity and higher package density for SiP devices has driven the development of new packaging technologies. In response, compartment shield technology makes it possible to put several functions into a single SiP without interference among the chips and double-side assembly technology greatly increases the chip density. Continued requests from customers in high technology markets require even further research into SiP technology. This report will discuss technologies that are currently being applied to SiPs and forecast what to expect in the future.

Snapshot spectral imaging: from spatial-spectral mapping to metasurface-based imaging.

Snapshot spectral imaging technology enables the capture of complete spectral information of objects in an extremely short period of time, offering wide-ranging applications in fields requiring dynamic observations such as environmental monitoring, medical diagnostics, and industrial inspection. In the past decades, snapshot spectral imaging has made remarkable breakthroughs with the emergence of new computational theories and optical components. From the early days of using various spatial-spectral data mapping methods, they have evolved to later attempts to encode various dimensions of light, such as amplitude, phase, and wavelength, and then computationally reconstruct them. This review focuses on a systematic presentation of the system architecture and mathematical modeling of these snapshot spectral imaging techniques. In addition, the introduction of metasurfaces expands the modulation of spatial-spectral data and brings advantages such as system size reduction, which has become a research hotspot in recent years and is regarded as the key to the next-generation snapshot spectral imaging techniques. This paper provides a systematic overview of the applications of metasurfaces in snapshot spectral imaging and provides an outlook on future directions and research priorities.

A Self-Adaptive Dual-ILRO Clock-Recovery Technique for Two-Tone Battery-Free Crystal-Free Neural-Recording SoC.

Wireless implantable devices are widely used in medical treatment, which should meet clinical constraints such as longevity, miniaturization, and reliable communication. Wireless power transfer (WPT) can eliminate the battery to reduce system size and prolong device life, while it's challenging to generate a reliable clock without a crystal. In this work, we propose a self-adaptive dual-injection-locked-ring-oscillator (dual-ILRO) clock-recovery technique based on two-tone WPT and integrate it into a battery-free neural-recording SoC. The 2[Formula: see text]-order inter-modulation (IM2) component of the two WPT tones is extracted as a low-frequency reference for battery-free SoC, and the proposed self-adaptive dual-ILRO technique extends the lock range to ensure an anti-interference PVT-robust clock generation. The neural-recording SoC includes a low-noise signal acquisition unit, a power management unit, and a backscatter circuit to perform neural signal recording, wireless power harvesting, and neural data transmission. Benefiting from the 6.4 μW low power of the clock recovery circuit, the overall SoC power is cut down to 49.8 μW. In addition, the proposed clock-recovery technique enables both signal acquisition and uplink communication to perform as well as that synchronized by an ideal clock, i.e., an effective number of 9.6 bits and a bit error rate (BER) less than 4.8 × 10-7 in chip measurement. The SoC takes a die area of 2.05 mm 2, and an animal test is conducted in a Sprague-Dawley rat to validate the wireless neural-recording performance, compared to a crystal-synchronized commercial chip.

Flexibility implications of optimal PV design: building vs. community scale

The Swiss Energy Strategy 2050 aims for a significant increase in renewable energy generation, with photovoltaic (PV) energy having the largest share. Such development challenges the balance between electricity supply and demand, which can be partly mitigated through optimized PV integration together with energy storage systems. This study investigates the optimal placement of rooftop and façade PV for a small energy community considering investment and operational costs, embodied and operational emissions, and financial and environmental benefits of excess on-site electricity production, as well as batteries and different heating system options. Additionally, a methodology is developed to quantify energy flexibility needs at both the building and community scale. A case study neighborhood, comprising three single-family and two multi-family homes is optimized across different scenarios. Results show that when individual self-consumption is considered, installing an air-to-water heat pump system with a heating buffer tank allows for smaller PV systems with better grid interaction conditions. When collective self-consumption is considered, an overall reduction in PV system size is observed, contributing to reduced energy flexibility needs by effectively lowering peak feed-in power and improving the match between on-site PV production and demand.

Techno-economic Optimization of an Offshore Hybrid Power System: Argentine Basin Case Study

Ocean observation and monitoring relies on data gathered from multiple sources including gliders, cabled observatories, underwater vehicles, and moored buoys. Moored buoys, augmented by resident autonomous underwater vehicles, are potentially well-suited to long-term oceanographic data collection with the resolution and scope of data collection increased by utilizing in-situ power generation. While power needs could be provided by a single generation source (e.g., diesel generator, solar photovoltaics, or wave energy converter) with battery backup, a hybrid power system can potentially smooth seasonal variations that would otherwise require large generation and storage capacities, and be tailored to a locations’ resource availability. By reducing system size through hybridization, we have the potential to reduce overall system cost. To this end, we developed an optimization model that defines the generator and storage capacities of the cost-optimal hybrid power system for a given location and load profile. The model considers generation by wave energy converters, wind turbines, solar photovoltaics, diesel generators, and current turbines with a battery for energy storage. The model uses the defined load profile and location specific time series of resource availability for a time-domain simulation of the power generated and battery state of charge. Based on the power system size, mooring, and mission specific maintenance schedule, the model calculates capital and operating costs for each potential combination of generation and storage capacities. The optimization model searches the 6-dimensional design space to find the lowest cost system that can satisfy the load requirements. In this paper, we focus on a case study of a hybrid power system serving an ocean observation buoy with a resident autonomous underwater vehicle located at the Mid-Atlantic Shelf Break. Diagnostic metrics such as the cost-breakdown and generator capacity factors are evaluated to understand cost drivers and draw comparisons to the costs of single generation systems. Additionally, the model sensitivity to key assumptions such as battery life, maintenance vessel cost, survival loads, and required persistence are discussed.

First report of Phytopythium vexans causing root rot on Macadamia integrifolia in China.

Soil-borne plant-pathogenic Phytopythium spp. can cause root rot and damping off on important plant species, resulting in serious economic loss. A survey in October 2021 identified soil-borne diseases occurring on Macadamia integrifolia in Yunnan Province, China. Microbes were isolated from necrotic roots of 23 trees with root rot symptoms by growing on cornmeal-based oomycete-selective 3P (Haas 1964) and P5APR (Jeffers and Martin, 1986) media at 24ºC in the dark for 7 days. Of the 56 single-hyphal isolates obtained, 18 were morphologically similar to Phytopythium vexans (van der Plaats-Niterink 1981; de Cock et al. 2015). Isolates LC04 and LC051 were selected for molecular analyses. The internal transcribed spacer (ITS) region and the cytochrome c oxidase subunit II (CoxII) gene were PCR-amplified using universal primers ITS1/ITS4 (White et al. 1990) and oomycete-specific primers Cox2-F/Cox2-RC4 (Choi et al. 2015), respectively. The PCR products were sequenced with the amplification primers and sequences were lodged in Genbank (Accession no. OM346742, OM415989 for ITS, OM453644, OM453643 for CoxII for isolates LC04 and LC051, respectively). The top BLAST hit in the Genbank nr database for all four sequences was Phytopythium vexans (>99% identity). A maximum-likelihood phylogenetic tree was constructed with analogous concatenated ITS and CoxII sequences from either type or voucher specimens of 13 Phytopythium species in the same phylogenetic clade as P. vexans (Table 1; Bala et. al 2010). Isolates LC04 and LC051 grouped most closely to P. vexans, with LC051 basal and sister to LC04 and P. vexans voucher specimen CBS119.80 with 100% support (Fig. 1). Millet seed inoculated with agar pieces colonized by P. vexans LC04 and LC51 was used to fulfill Koch's postulates (Li et al. 2015) in a completely randomized experimental design. Four 6-month-old M. integrifolia var. Keaau (660) seedlings were transplanted into pasteurized commercial potting mix containing 0.5% (w/w) inoculum. Plants were grown in free draining pots and watered once a day. At 14 days post-inoculation, roots were discolored compared to control plants inoculated with millet seed mixed with agar plugs lacking P. vexans (Fig. 2). By 30 days post-inoculation, infected roots were discolored with obvious decay and reduction in root system size. Control plants were symptomless. P. vexans was successfully re-isolated from two lesioned roots from each plant. The infection experiment was done twice, demonstrating that P. vexans LC04 and LC51 caused root disease on M. integrifolia. P. vexans causes root rot, damping-off, crown rot, stem rot or patch canker on economically important trees in many parts of the world, including seven plant species in China (Farr and Rossman 2022). This is the first report of pathogenic P. vexans on M. integrifolia in China. Reports of pathogenic P. vexans on multiple hosts in several parts of the world suggest it should be considered a quarantine risk and included in risk mitigation or pest management plans that include other species of Phytopythium, or species of Pythium or Phytophthora, to which P. vexans has many similarities (de Cock et al. 2015).

Integrated Common-Mode Filter for GaN Power Module With Improved High-Frequency EMI Performance

While the employment of wide bandgap (WBG) devices in high-frequency and high-voltage applications brings benefits such as reduced system size and improved efficiency, it aggravates the electromagnetic interference (EMI) issue due to fast switching. High-frequency EMI noise suppression relies mainly on the filter design, where the filter's performance is strongly affected by parasitics. Through analyzing the common-mode (CM) equivalent circuit of a half-bridge power module, this letter identifies the key parasitics that dominate the performance of a common-mode filter (CMF) at high frequencies. To minimize the parasitics, the concept of integrating the CMF inside the WBG power module package is developed to improve the noise attenuation. A π-type CMF is integrated with a half-bridge GaN-based power module as a prototype to validate the concept. Experiments are conducted by measuring the CM noise spectrum received by the line impedance stabilization networks (LISNs) from the hard switching of the designed power module under 70 V and 80 kHz. Comparing the measured results of the integrated CMF to the externally-added CMF, up to 50 dBμV more attenuation is achieved by the integrated CMF in the frequency range of 10 MHz to 100 MHz, verifying the theoretical analysis and the established CM equivalent circuit.

Design of Wafer Level Solder Seals – A Surface Energy Perspective

Wafer level vacuum packaging of quartz resonators and microelectromechanical system (MEMS) inertial sensors and RF switches have been successfully demonstrated by a number of investigators. The majority of these devices were sealed using reflow of gold-tin solder because of its superior hermeticity and benign processing conditions as compared to seals made using glass frit or anodic bonding. These successes have motivated efforts to integrate multiple sensors and active silicon devices within the same package to achieve improved performance and further reduce system size and cost. Sealing these large, heterogeneous assemblies at wafer level presents a more challenging problem than sealing small individual sensors, primarily due to wafer bow and irregularities in the seal surfaces. Wafer bow has been addressed in sealing wafers of individual sensors by plating metal stops adjacent to the seal rings, which allow the wafers to be pressed together to flatten the seal areas during bonding. This strategy cannot always be applied to sealing system devices because the amount of wafer bow is greater than that associated with more uniform wafers of sensors and the larger area of system devices increase the residual stress on the solder seal. An alternative approach to pressing wafers flat throughout the bond process would be to relax the force during reflow and allow the solder to bridge the nonplanar interface. We have used analytical and numerical calculations to investigate the interplay between seal width, height and shape of the seal gap, and solder volume associated with this bonding strategy. A set of soldering experiments were conducted on test articles that allowed us to independently vary these parameters to evaluate our model predictions.

LightX3ECG: A Lightweight and eXplainable Deep Learning System for 3-lead Electrocardiogram Classification

Cardiovascular diseases (CVDs) are a group of heart and blood vessel disorders that is one of the most serious dangers to human health, and the number of such patients is still growing. Early and accurate detection plays a key role in successful treatment and intervention. Electrocardiogram (ECG) is the gold standard for identifying a variety of cardiovascular abnormalities. In clinical practices and most of the current research, standard 12-lead ECG is mainly used. However, using a lower number of leads can make ECG more prevalent as it can be conveniently recorded by portable or wearable devices. In this research, we develop a novel deep learning system to accurately identify multiple cardiovascular abnormalities by using only three ECG leads which are I, II, and V1. Specifically, we use three separate One-dimensional Convolutional Neural Networks (1D-CNNs) as backbones to extract features from three input ECG leads separately. The architecture of 1D-CNNs is redesigned for high performance and low computational cost. A novel Lead-wise Attention module is then introduced to aggregate outputs from these three backbones, resulting in a more robust representation which is then passed through a Fully-Connected (FC) layer to perform classification. Moreover, to make the system’s prediction clinically explainable, the Grad-CAM technique is modified to produce a highly meaningful lead-wise explanation. Finally, we employ a pruning technique to reduce system size, forcing it suitable for deployment on hardware-constrained platforms. The proposed lightweight, explainable system is named LightX3ECG. We get classification performance in terms of F1 scores of 0.9718 and 0.8004 on two large-scale ECG datasets, i.e., Chapman and CPSC-2018, respectively, which surpass current state-of-the-art methods while achieving higher computational and storage efficiency. Visual examinations and a sanity check are also performed to strictly demonstrate the strength of our system’s interpretability.

Design and Implementation of Multisite Stimulation System Using a Double-Tuned Transmitter Coil and Miniaturized Implants.

This letter presents a double-tuned dual input transmitter coil operating at 13.56 MHz and 40.68 MHz industrial, scientific, and medical (ISM) bands for multisite biomedical applications. The proposed system removes the need for two separate coils, which reduces system size and unwanted couplings. The design and analysis of the double-tuned transmitter coil using a lumped element frequency trap are discussed in this letter. The transmitter achieves measured matching of -26.2 dB and -21.5 dB and isolation of -17.7 dB and -11.7dB at 13.56 MHz and 40.68 MHz, respectively. A 3 mm × 15 mm flexible coil is used as an implantable receiver. This letter shows synchronized multisite stimulation of two flexible implants at a distance of 2 cm while covered with 1 cm chicken breast.

Accurate estimation of dynamical quantities for nonequilibrium nanoscale systems.

Fluctuations of dynamical quantities are fundamental and inevitable. For the booming research in nanotechnology, huge relative fluctuation comes with the reduction of system size, leading to large uncertainty for the estimates of dynamical quantities. Thus, increasing statistical efficiency, i.e., reducing the number of samples required to achieve a given accuracy, is of great significance for accurate estimation. Here we propose a theory as a fundamental solution for such problem by constructing auxiliary path for each real path. The states on auxiliary paths constitute canonical ensemble and share the same macroscopic properties (NVT) with the initial states of the real path. By implementing the theory in molecular dynamics simulations, we obtain a nanoscale Couette flow field with an accuracy of 0.2μm/s with relative standard error <0.1. The required number of samples is reduced by 12 orders compared to conventional method. The predicted thermolubric behavior of water sliding on a self-assembled surface is directly validated by experiment under the same velocity. This theory only assumes the system is initially in thermal equilibrium, then driven from that equilibrium by an external perturbation. It could serve as a general approach for extracting the accurate estimate of dynamical quantities from large fluctuations to provide insights on atomic level under experimental conditions, and benefit the studies on mass transport through (biological) nanochannels and fluid film lubrication of nanometer thickness.

Monolithic Sensor Integration in CMOS Technologies

Besides being mainstream for mixed-signal electronics, CMOS technology can be used to integrate micro-electromechanical system (MEMS) on a single die, taking advantage of the structures and materials available in feature sizes around 180 nm. In this article, we demonstrate that the CMOS back-end-of-line (BEOL) layers can be postprocessed and be opportunistically used to create several kinds of MEMS sensors exhibiting good or even excellent performance, such as accelerometers, pressure sensors, and magnetometers. Despite the limitations of the available mechanical and material properties in CMOS technology, due to monolithic integration, these are compensated by the significant reduction of parasitics and system size. Furthermore, this work opens the path to create monolithic integrated multisensor (and even actuator) chips, including data fusion and intelligent processing.