Cell Array Research Articles

Design of Hybrid multi-level inverter for photovoltaic(PV) application

Nowadays the demand and consumption of energy increase in the word. Due to high cost of fossil fuel it’s not able to meet the required power generation demand. But the developed and developing countries encourage to generate power from renewable energy sources. The developed countries manage their resources in such a manner that they will fulfill their needs today and in the future as well. Nevertheless, the developing countries have limited sources of fossil fuels, which may decrease day by day. For this problem, the alternate solution is required, which is renewable energy. The output of renewable i.e. photovoltaic (PV) is DC. Now this is a challenging task for the researcher to integrate the renewable energy into the ac grid. For the reliable future of the power system, it is imperative for the modern era to integrate non-conventional sources into the AC power grid.The use of photovoltaic cells is increasing dramatically in all areas of life because of their small environmental impact, pollution-free, minimal maintenance, and zero noise. The real work focuses on the integration of PV systems with the proposed new topology called Multi-level inverters based on switch dc sources for low, medium and high power applications. An inverter is a power electronics device that converts DC input to AC output voltage. Input DC voltage is obtains from PV cell array, fuel cell or any other source.The output of PV panels is use as DC input voltage source for the proposed inverter. Single-phase multi level inverter is use to convert dc power receiving form PV array to AC power. First single phase two level inverter introduce which have many problems like those that high value capacitor required at output and high total harmonics distortion’s (THD). Nevertheless, as the number of level increased in inverter output the number of electronic switches also increased which may increase the losses.Multi-level inverters are gave more attention for high power applications. In recent years, lower order harmonic components has been developed to operate at higher switching frequencies.On the other side as the number of level increased the output waveform approach to sinusoidal waveform and the harmonics decreased. Output voltage and current waveforms are obtains and THDs are analyze. The multi-level inverter used in un-interrupted power supply (UPS), variable frequency drives (VFD), pumps etc. The performance of single-phase multi-level inverter will be analyzed in MATLAB / Simulink software.

Active Tracking of Temporally Changing Gas-Phase Odor Mixture Using an Array of Cells Expressing Olfactory Receptors.

A cell expressing an olfactory receptor (OR) exhibits excellent odorant detection ability and thus is widely applied in odor biosensors. Most of those biosensors, however, could detect only liquid-phase nonchanging single-component odorants. In this paper, we raised up an odor biosensor for the active tracking of temporally changing gas-phase odor mixture by an array of cells expressing ORs. A thin stable liquid film covered the cell, thus allowing gas-phase odorants to penetrate. The online image processing generated individual cell brightness data which were used to compute the biosensor response. Based on the obtained responses, we adjusted the known odor components to be similar with the unknown odor. The function of our biosensor was validated by tracking the variable single-component odorant or the binary odor mixture. The influence from the sensor drift could be overcome by comparing the adjacent unknown and known odor responses. In the odor mixture quantification, adding the OR label to mixed cells and then quantifying separately (named as the pre-label method) was more efficient, while directly using the cell response pattern (named as the label-free method) was still capable even if the OR odor had cross-sensitivity.

Engineering a Point-of-Care Paper-Microfluidic Electrochemical Device Applied to the Multiplexed Quantitative Detection of Biomarkers in Sputum.

Health initiatives worldwide demand affordable point-of-care devices to aid in the reduction of morbidity and mortality rates of high-incidence infectious and noncommunicable diseases. However, the production of robust and reliable easy-to-use diagnostic platforms showing the ability to quantitatively measure several biomarkers in physiological fluids and that could in turn be decentralized to reach any relevant environment remains a challenge. Here, we show the particular combination of paper-microfluidic technology, electrochemical transduction, and magnetic nanoparticle-based immunoassay approaches to produce a unique, compact, and easily deployable multiplex device to simultaneously measure interleukin-8, tumor necrosis factor-α, and myeloperoxidase biomarkers in sputum, developed with the aim of facilitating the timely detection of acute exacerbations of chronic obstructive pulmonary disease. The device incorporates an on-chip electrochemical cell array and a multichannel paper component, engineered to be easily aligned into a polymeric cartridge and exchanged if necessary. Calibration curves at clinically relevant biomarker concentration ranges are produced in buffer and artificial sputum. The analysis of sputum samples of healthy individuals and acutely exacerbated patients produces statistically significant biomarker concentration differences between the two studied groups. The device can be mass-produced at a low cost, being an easily adaptable platform for measuring other disease-related target biomarkers.

Performance Analysis and Multilayer Design of Curved Honeycomb Sandwich Panels with Different Cell Arrays Under Projectile Impact

The cell array type significantly affects the global stresses in curved honeycomb sandwich panels. In this study, the curved sandwich panels with the out-plane honeycomb core (COP) and the in-plane honeycomb core (CIP) are proposed. Their local impact resistance is numerically investigated using finite element simulation calibrated with air cannon test results. Various impact scenarios including different projectile diameters, different impacting velocities, angles, as well as locations are considered. The performances of the COP and CIP panels with similar overall mass and relative density are compared by evaluating their impact histories and energy absorption properties. It is demonstrated that the CIP panel shows improved impact mitigation and energy absorption property under local impact. However, its overall displacement is significantly larger than that of the COP panel. Based on the impact behavior of COP and CIP panels, the hybrid two-layer structures (HOI and HIO) are designed. It is found that the HIO panel shows an increase in energy absorption of approximately 3% over the COP and CIP panels and a reduction in the overall displacement of at least 28% over the CIP panel. Moreover, HIO configuration with the thinner cell wall thickness of the upper core demonstrates improved impact mitigation.

A comprehensive study of parallel gap resistance welding joint between Ag foil and front electrode of GaAs solar cell

When space solar cell array is subjected to harsh temperature cycle, such as planet orbit, thermal fatigue cracks in bonding area are easily induced. With the aim of improving bonding quality and elucidating failure mechanism of parallel gap resistance welding (PGRW) joints in temperature cycling environment, the present research investigates the effect of current density on bonding quality and thermal fatigue behavior of PGRW joint between Ag interconnector and front electrode of GaAs solar cell. When current density is set at 417 A/mm2, a solid diffusion bonding is achieved at the Ag/Au interface, which also possesses adequate joint strength as ensured by both pressure and input energy of PGRW. Crack initiation by thermal fatigue is found at joint edge, which subsequently propagates along the interface as the environment temperature cycling continues. Further investigation reveals that the conducted temperature cycling generates serious tensile and compressive stress in the multi-layered joint structure. Since such reciprocating forces directly induce micro-plastic deformation and strain accumulation at joint interface, failure by crack is finally generated at the joining interface.

Approximate simulation of cortical microtubule models using dynamical graph grammars

Dynamical graph grammars (DGGs) are capable of modeling and simulating the dynamics of the cortical microtubule array (CMA) in plant cells by using an exact simulation algorithm derived from a master equation; however, the exact method is slow for large systems. We present preliminary work on an approximate simulation algorithm that is compatible with the DGG formalism. The approximate simulation algorithm uses a spatial decomposition of the domain at the level of the system’s time-evolution operator, to gain efficiency at the cost of some reactions firing out of order, which may introduce errors. The decomposition is more coarsely partitioned by effective dimension (d = 0 to 2 or 0 to 3), to promote exact parallelism between different subdomains within a dimension, where most computing will happen, and to confine errors to the interactions between adjacent subdomains of different effective dimensions. To demonstrate these principles we implement a prototype simulator, and run three simple experiments using a DGG for testing the viability of simulating the CMA. We find evidence indicating the initial formulation of the approximate algorithm is substantially faster than the exact algorithm, and one experiment leads to network formation in the long-time behavior, whereas another leads to a long-time behavior of local alignment.

Angle-independent metamaterial absorber for S-, C-, and X-band application

Abstract In this paper, the development and designing of angle-independent metamaterial microwave absorbers are presented. The unit cell consists of two concentric circle that are linked by consolidated resistors. The absorber is built on a dielectric substrate (FR4) with a thickness of 3.2 mm (λ/0.07) and a dielectric constant of 4.3. The wideband absorption is acquired in the range of 2.8 to 10.42 GHz with a wide band of 7.62 GHz with absorptivity above 90%. In the area of interest, a flat band is obtained, and to examine the current distribution and electric field in the respective region, two peaks are considered at a frequency of 3.66 and 9.54 GHz, with maximum absorptivity of 99.99% and 99.44%, respectively. The presented absorber is examined under different angles for phi and theta variation. From the phi variation, it is observed that for all the angles, absorptivity does not vary, which confirms that the absorber is acting as an angle independent. The fabricated sheet consists of an array of a unit cell, which is examined inside the anechoic chamber with the help of two horn antennas and vector network analyzer. The tested and simulated results are compared, and it was observed that they are close in their agreement. At the end of the manuscript, the presented and already reported arts are compared, and it is observed that the presented one operates for the low frequency with higher bandwidth. The presented absorber can be practically used for defense applications for Radar Cross Sections reduction.

Miniaturized Polarization-Insensitive Rectifying Metasurface for Powering Internet of Things Devices

In this paper, a miniaturized polarization-insensitive rectifying metasurface unit cell is proposed for powering electric devices of Internet-of-Things (IoT). The metasurface, an array of periodic unit cells, consists of two layers of substrate and three layers of metal. The metasurface unit cell is composed of eight asymmetric dipoles, which are arranged orthogonally and closely on both surfaces of the upper substrate. The strong coupling between dipoles induces extra reactive components, which makes the unit size be miniaturized to only 0.15 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> . The miniaturization mechanism is analyzed by the equivalent circuit theory. The simulation results show that the harvesting efficiency for arbitrary polarized waves are higher than 90% from 2.2 to 2.7 GHz (20%). Being integrated with Schottky diodes at the proper position, the rectifying metasurface is designed. A 2 × 2 array with the size of 0.3 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> × 0.3 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> was fabricated and measured. The maximum harvesting-rectifying efficiency is 61% at 2.45 GHz under different polarization angles. When the power density is 8 mW/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , 80 mW direct current (DC) power could be obtained.

Recognizing Hand Gestures Using Solar Cells

We design a system, SolarGest, which can recognize hand gestures near a solar-powered device by analyzing the patterns of the photocurrent. SolarGest is based on the observation that each gesture interferes with incident light rays on the solar panel in a unique way, leaving its discernible signature in harvested photocurrent. Using solar energy harvesting laws, we develop a model to optimize design and usage of SolarGest. To further improve the robustness of SolarGest under non-deterministic operating conditions, we combine dynamic time warping with Z-score transformation in a signal processing pipeline to pre-process each gesture waveform before it is analyzed for classification. We evaluate SolarGest with both conventional opaque solar cells as well as emerging see-through transparent cells. Our experiments demonstrate that SolarGest achieves 99% for six gestures with a single cell and 95%for fifteen gesture with a22solar cell array. The power measurement study suggests that SolarGest consume 44% less power compared to light sensor based systems.

Antireflection and radiative cooling difunctional coating design for silicon solar cells.

Passive daytime radiative cooling (PDRC) as a zero-energy consumption cooling method has broad application potential. Common commercial crystalline silicon (c-Si) solar cell arrays suffer working efficiency loss due to the incident light loss and overheating. In this work, a radiative cooler with PDMS (polydimethylsiloxane) film and embedded SiO2 microparticles was proposed to use in silicon solar cells. Both anti-reflection and radiative cooling performance can be improved through numerical parametric study. For the best performing of PDMS/SiO2 radiative cooler, the thickness of PDMS layer, volume fraction and radius of the embedded SiO2 particles have been determined as 55 µm, 8% and 500 nm, respectively. 94% of emissivity in first atmospheric window band (8-13 µm) for radiative cooling and 93.4% of solar transmittance at the crystalline silicon absorption band (0.3-1.1 µm) were achieved. We estimated that the PDMS/SiO2 radiative cooler can lower the temperature of a bare c-Si solar cell by 9.5°C, which can avoid 4.28% of efficiency loss. More incident light can enter and be utilized by silicon layer to enhance the efficiency of the solar cells. The proposed difunctional radiative cooling coating may become guidance for next generation encapsulation of crystalline silicon solar cells.

Establishment of a cascaded microfluidic single cell analysis system for molecular and functional heterogeneity analysis of circulating tumor cells

Single cell heterogeneity analysis of circulating tumor cells (CTCs) is expected to reveal important tumor biological information for the evaluation and prediction of tumor stage and metastatic progression. Although various methods have been proposed to isolate and detect CTCs, consecutive CTCs sorting and in-situ multi-dimensional heterogeneity analysis in a cascaded system remain challenging. Here, a cascaded microfluidic chip was constructed, successively integrating a spiral structure for size-based removal of blood cells and a single cell array structure for the subsequent capture of CTCs, complementing the advantages of high throughput and high separation purity for both structures. Importantly, the molecular and functional heterogeneity analysis of CTCs can be in-situ realized and real-time observed at the single-cell level. Using this system, we captured CTCs and situ-analyzed the heterogeneity of single CTCs from different types of cancer patients, finding that mesenchymal phenotype is present in more CTCs at the advanced stage, and CTCs show active motility and division ability in metastatic patients. Therefore, the cascaded microfluidic chip offers an effective strategy for studying the molecular and functional heterogeneity of single CTCs, providing critical information for the evaluation of tumor progression and metastasis.

A transceiver integrated piezoelectric micromachined ultrasound transducer array for underwater imaging

In this article, a scandium-doped aluminum nitride (Sc0.2Al0.8N) piezoelectric micromachined ultrasound transducer (PMUT) array for underwater imaging is presented. The reported PMUT array integrates a transmitter and a receiver in one transduction cell, in which the outer top electrode is used for transmitting while the inner top electrode is employed for simultaneously receiving ultrasonic waves, respectively. A 7 × 8 transduction cell array with characteristic size of 500μm is designed in a bioinspired honeycomb architecture and developed based on a piezoelectric on silicon-on-insulator (SOI) platform. The top electrode of the transduction cell is split into the outer and inner sections with the optimized size ratio for achieving transceiver integration in one cell. The fabricated PMUT array exhibits a transmit sensitivity of 146.59 dB (re: 1 μPa/V), and a receive sensitivity of −173.70 dB (re: 1 V/μPa) at its resonant frequency of around 150 kHz in water. In order to demonstrate the feasibility of underwater imaging, the PMUT array and its signal conditional circuits are packaged using an acoustically transparent material. Ultrasonic pulse-echo imaging with the developed PMUT array is demonstrated without implementation of a switching circuit to separate the transmit and reflected signals, due to the transceiver integration approach proposed in our work. This work demonstrates the feasibility of underwater imaging for the transceiver integrated PMUT array, which has great commercial value for minimized and portable underwater imaging.

Thermal performance assessment for an array of cylindrical Lithium-Ion battery cells using an Air-Cooling system

Modern society depends on energy storage systems like Lithium-ion (Li-ion) batteries. Li-ion battery cells are delicate to changes in temperature. Extreme environmental conditions affect their life cycle and performance. Therefore, effective cell temperature management is a must for secure and dependable battery operation. Additionally, the high production costs of electric cars must be countered by the adaptability of the battery pack design for modern electric vehicles. As the chemical reactions generate more heat and raise the battery's temperature, it may cause the battery to explode and cause fires in the workplace. To address this issue, the present work attempts to numerically study a novel design of an efficient air-cooling system for improving the performance of lithium-ion batteries by reducing the operational temperatures under a different coolant flow rate. The main output of the presented study is the analysis of a novel design of an efficient air-cooling system for lithium-ion batteries. The study aims to reduce the operational temperatures of the batteries under different coolant flow rates to improve their performance and service life. The numerical simulations are carried out using a finite volume-based computing tool with the K-epsilon (k-ε) turbulence model. The analysis is performed for various pertinent parametric ranges, including the spacing between the batteries, Reynolds numbers, and average Nusselt numbers. The results indicate that increasing air inlet velocity (Re) substantially reduces the average air temperature of the cooling pack and temperature difference (ΔT) of the battery cells, and the cooling pack's average heat transfer rate (Nu) increases monotonically as the Re increases.

Avalanche Photodiodes and Silicon Photomultipliers of Non-Planar Designs

Conventional designs of an avalanche photodiode (APD) have been based on a planar p–n junction since the 1960s. APD developments have been driven by the necessity to provide a uniform electric field over the active junction area and to prevent edge breakdown by special measures. Most modern silicon photomultipliers (SiPM) are designed as an array of Geiger-mode APD cells based on planar p–n junctions. However, the planar design faces an inherent trade-off between photon detection efficiency and dynamic range due to loss of an active area at the cell edges. Non-planar designs of APDs and SiPMs have also been known since the development of spherical APDs (1968), metal-resistor-semiconductor APDs (1989), and micro-well APDs (2005). The recent development of tip avalanche photodiodes (2020) based on the spherical p–n junction eliminates the trade-off, outperforms the planar SiPMs in the photon detection efficiency, and opens new opportunities for SiPM improvements. Furthermore, the latest developments in APDs based on electric field-line crowding and charge-focusing topology with quasi-spherical p–n junctions (2019–2023) show promising functionality in linear and Geiger operating modes. This paper presents an overview of designs and performances of non-planar APDs and SiPMs.

ОПРЕДЕЛЕНИЕ ЭФФЕКТИВНОГО МОДУЛЯ ЮНГА БИОКОМПОЗИТА КОСТЬ–ТИТАН, ОБРАЗОВАННОГО В РЕЗУЛЬТАТЕ ПОЛНОЙ ОСТЕОИНТЕГРАЦИИ ИМПЛАНТАТА

The objective of study is to determine the effective Young modulus before and after the completed osseointegration process using mathematical modelling of a titanium porous structure. A novel model is proposed in the form of 3D arrays of Gibson-Ashby cells with rigid clamping of horizontal beams resting on elastic foundation. Calculations made on the basis of the developed model are compared with known models and literature data. The assumption is proved that the osseointegration process due to the bone tissues ingrowth into the pores of titanium implant could affect the Young modulus increasing its value in proportion to porosity of a specimen.

Strain investigation of PECVD passivation layer for ferroelectric domain wall random access memory

Ferroelectric domain-wall random access memory (DWRAM), based on the utilization of highly conductive domain walls in insulating ferroelectric LiNbO3 (LNO) single-crystal thin films, holds great promise for the future of memory storage. The ability to scale this technology up in a crossbar architecture means that it has the otential to surpass the storage density capabilities of commercial ferroelectric random access memory devices. Nevertheless, the passivation layer in the vertically integrated structure (VIS) architecture is critical because it affects many vital parameters of the memory such as retention, on/off current ratio, reliability, etc. Therefore, a detailed strain investigation of silicon nitride and silicon dioxide fabricated by plasma-enhanced chemical vapor deposition (PECVD) is presented. Furthermore, the effect of residual strain on the electrical properties of LNO DW cells was investigated. The results indicated that a monolayer of SiO2 or Si3N4 is not a good choice for the insulating layer because of the undesirable passivation caused by defects and residual strain. Hence, a Si3N4/SiO2 composite passivation layer is proposed, which not only solves the residual strain problem but also ensures good insulation performance. Finally, a crossbar array of DW memory cells with an on/off current ratio greater than 104 was fabricated using the Si3N4/SiO2 composite dielectric layer, demonstrating good uniformity and retention. This work validates the feasibility of high-density integration of LNO domain wall memories and provides a foundation for selecting passivation layers in the VIS architecture.

Ultrathin Crystalline Silicon Nano and Micro Membranes with High Areal Density for Low-Cost Flexible Electronics.

Ultrathin crystalline silicon is widely used as an active material for high-performance, flexible, and stretchable electronics, from simple passive and active components to complex integrated circuits, due to its excellent electrical and mechanical properties. However, in contrast to conventional silicon wafer-based devices, ultrathin crystalline silicon-based electronics require an expensive and rather complicated fabrication process. Although silicon-on-insulator (SOI) wafers are commonly used to obtain a single layer of crystalline silicon, they are costly and difficult to process. Therefore, as an alternative to SOI wafers-based thin layers, here, a simple transfer method is proposed for printing ultrathin multiple crystalline silicon sheets with thicknesses between 300nm to 13µm and high areal density (>90%) from a single mother wafer. Theoretically, the silicon nano/micro membrane can be generated until the mother wafer is completely consumed. In addition, the electronic applications of silicon membranes are successfully demonstrated through the fabrication of a flexible solar cell and flexible NMOS transistor arrays.

Compact conformal metasurface antenna for hyperthermia applications

In this paper, the design, analysis and evaluation of a new compact conformal metasurface (MTS)-based bow-tie slot antenna is presented for hyperthermia treatment of cancer. A bow-tie slot antenna in close proximity with tissue designed at 2.45 GHz was used to excite the MTS layer, which is made of a 4 × 4 uniform array of square unit cells. The proposed MTS-based antenna is compact and provides enhanced penetration depth in the tissue medium as compared to the bow-tie antenna only. To verify the design concept, both the proposed MTS-based antenna and bow-tie antenna were fabricated, and the measured results are well anticipated. Finally, the MTS applicator is terminated with water bolus and tissue to characterize its hyperthermia performance in a real scenario. The key features of the proposed MTS applicator include wide impedance bandwidth (stable hyperthermia performance), enhanced penetration depth and effective field size, single-layer structure and ease of fabrication.

Experimental and finite element analysis of utilizing rectangular and trapezoidal piezoelectric energy harvester with arrays of auxetic cells

Present study develops the experimental and finite element analysis of an auxetic piezoelectric energy harvester consisting of a cantilever, auxetic substrate, and piezoelectric layer. Firstly, five auxetic models with 1, 4, 9, 16, and 25 honeycomb auxetic cells are presented. Harvested power and stress distribution of the piezoelectric layer for these models are compared with plain piezoelectric energy harvester. All the analysis has been performed using the experimental tests and finite element method. Mesh size sensitivity analysis of the finite element model is presented, and it is verified by previous experimental studies. The model with 25 auxetic cells harvests more power than other models. Furthermore, comparing stress distribution on the piezoelectric layer of these models indicates that increasing the number of auxetic cells leads to increasing the average stress on the piezoelectric layer. The present investigation illustrates that harvested power of an auxetic energy harvester in resonant frequency could improve to twenty times more than a plain harvester. Besides, the new auxetic model with trapezoidal geometry is presented in the present paper. Utilizing this model as the substrate in a piezoelectric energy harvester leads to increasing the efficiency of the energy harvester by 82.5%. The damping ratio of the auxetic energy harvester has been measured by experimental investigation. Also, experimental analysis has been performed to find the optimum energy harvester circuit resistor. The density of the harvested power for the trapezoidal energy harvester with an optimum circuit resistor is 107% more than the rectangular energy harvester.

A numerical modeling of thermal management of high CPV arrays using spray cooling

Liquid cooling is an efficient way of thermal management for high CPV cells, increasing the system performance by reducing cell's temperature. Thermal management complexity rises upon using an array of cells while the system becomes sizeable. The present numerical simulations follow a single cell study to investigate spray cooling for high CPV arrays with minimum number of injecting nozzles. The idea is to cool the cells by the liquid film formed on the thermal paste surface. Cooling the whole surface by the help of the liquid film decreases the number of nozzles to less than the number of cells. Both mass flow rate and pumping power are reduced, improving the system efficiency and lowering the liquid demands. To find cooling patterns, one-dimensional arrays with two and three cells and two-dimensional square arrays of order two and three are investigated at three solar concentrations; 500, 750, and 1000 Suns. The non-spraying cells' performance is assessed by consideration of two criteria; the damaging temperature and the increment rate of the difference between the cell power operating with and without injection. It is indicated that the patterns from smaller arrays can be applied to design the injection arrangement for the larger ones. Results from the cooling injection on a square array of order three demonstrate that decreasing the number of nozzles can reduce the mass flow rate by 55–89 % and increase the net power by 0.5–2.2 %, depending on the concentration ratio.