Flexible Panel Research Articles

Shock-wave/turbulent boundary-layer interaction with a flexible panel

The dynamic coupling between a Mach 2.0 shock-wave/turbulent boundary-layer interaction (STBLI) and a flexible panel is investigated. Wall-resolved large-eddy simulations are performed for a baseline interaction over a flat-rigid wall, a coupled interaction with a flexible panel, and a third interaction over a rigid surface that is shaped according to the mean panel deflection of the coupled case. Results show that the flexible panel exhibits self-sustained oscillatory behavior over a broad frequency range, confirming the strong and complex fluid–structure interaction (FSI). The first three bending modes of the panel oscillation are found to contribute most to the unsteady panel response, at frequencies in close agreement with natural frequencies of the mean deformed panel rather than those for the unloaded flat panel. This highlights the importance of the mean panel deformation and the corresponding stiffening in the FSI dynamics. The time-averaged flow shows an enlarged reverse-flow region in the presence of mean surface deformations. The separation-shock unsteadiness is enhanced due to the panel motion, leading to higher wall-pressure fluctuations in the coupled interaction. Spectral analysis of the separation-shock location and bubble-volume signals shows that the STBLI flow strongly couples with the first bending mode of the panel oscillation. This is further confirmed by dynamic mode decomposition of the flow and displacement data, which reveals variations in the reverse-flow region that follow the panel bending motion and appear to drive the separation-shock unsteadiness. Low-frequency modes that are not associated with the fluid–structure coupling, in turn, are qualitatively similar to those obtained for the rigid-wall interactions, indicating that the characteristic low-frequency unsteadiness of STBLI coexists with the dynamics emerging from the fluid–structure coupling. Based on the present results, unsteady FSIs involving STBLIs and flexible panels are likely to accentuate rather than mitigate the undesirable features of STBLIs.

Marine Monitoring System Powered by Flexible Solar Panel

Marine Monitoring System Powered by Flexible Solar Panel

Smart materials for flexible electronics and devices: hydrogel.

In recent years, flexible conductive materials have attracted considerable attention for their potential use in flexible energy storage devices, touch panels, sensors, memristors, and other applications. The outstanding flexibility, electricity, and tunable mechanical properties of hydrogels make them ideal conductive materials for flexible electronic devices. Various synthetic strategies have been developed to produce conductive and environmentally friendly hydrogels for high-performance flexible electronics. In this review, we discuss the state-of-the-art applications of hydrogels in flexible electronics, such as energy storage, touch panels, memristor devices, and sensors like temperature, gas, humidity, chemical, strain, and textile sensors, and the latest synthesis methods of hydrogels. Describe the process of fabricating sensors as well. Finally, we discussed the challenges and future research avenues for flexible and portable electronic devices based on hydrogels.

Design and Assessment of a solar collector system for low-cost, pollution-free cooking and grilling applications

Recently, using solar energy for several purposes has become very important to preserve the environment, reduce pollution, and reduce consumption. Examples of these applications are cooking, barbecuing, desalination, and generating electrical power. Solar oomph is extremely important in providing the energy used in cooking. In the current work, a solar collector consisting of six flexible reflective panels was designed and assembled for solar cooking and grilling operations in the city of Jazan, southwestern Saudi Arabia. Pots of different sizes have been prepared for cooking operations, as well as a grid for grilling operations. They are installed at the center of the collection of reflected rays from the solar center, in addition to a movable stand and a manual system for directing the direction of the falling sunlight. The current solar energy system provides an estimated power of about 2,300 watts from 9 a.m. to 5 p.m. It took 16 minutes to cook 2700 grams of vegetables with the current system and less than two minutes to boil 2 liters of water. Grilling a whole chicken weighing 800 grams, cut in half, takes about ten minutes. Cooking was also done inside the kitchen using a solar energy source by transferring heat from the solar concentrator's absorber to a 35-diameter pipe filled with vegetable oil as a heat transfer fluid. The absorber temperature reached 321 degrees Celsius, while the internal cooking stove registered 129 degrees. The storage of collected heat and how it is transferred to indoor cooking processes were also studied.

Ruptured liquid metal microcapsules enabling hybridized silver nanowire networks towards high-performance deformable transparent conductors.

Extensive studies have been carried out on silver nanowires (AgNWs) in view of their impressive conductivity and highly flexible one-dimensional structure. They are seen as a promising choice for producing deformable transparent conductors. Nonetheless, the widespread adoption of AgNW-based transparent conductors is hindered by critical challenges represented by the significant contact resistance at the nanowire junctions and inadequate interfacial adhesion between the nanowires and the substrate. This study presents a novel solution to tackle the aforementioned challenges by capitalizing on liquid metal microcapsules (LMMs). Upon exposure to acid vapor, the encapsulated LMMs rupture, releasing the fluid LM which then forms a metallic overlay and hybridizes with the underlying Ag network. As a result, a transparent conductive film with greatly enhanced electrical and mechanical properties was obtained. The transparent conductor displays negligible resistance variation even after undergoing chemical stability, adhesion, and bending tests, and ultrasonic treatment. This indicates its outstanding adhesion strength to the substrate and mechanical flexibility. The exceptional electrical properties and robust mechanical stability of the transparent conductor position it as an ideal choice for direct integration into flexible touch panels and wearable strain sensors, as evidenced in this study. By resolving the critical challenges in this field, the proposed strategy establishes a compelling roadmap to navigate the development of high-performance AgNW-based transparent conductors, setting a solid foundation for further advancement in the field of deformable electronics.

Multi-role conductive hydrogels for flexible transducers regulated by MOFs for monitoring human activities and electronic skin functions.

Metal organic frameworks (MOFs) have garnered significant attention in the development of stretchable and wearable conductive hydrogels for flexible transducers. However, MOFs used in hydrogel networks have been hampered by low mechanical performance and poor dispersibility in aqueous solutions, which affect the performance of hydrogels, including low toughness, limited self-recovery, short working ranges, low conductivity, and prolonged response-recovery times. To address these shortcomings, a novel approach was adopted in which micelle co-polymerization was used for the ex situ synthesis of Zn-MOF-based hydrogels with exceptional stretchability, robust toughness, anti-fatigue properties, and commendable conductivity. This breakthrough involved the ex situ integration of Zn-MOFs into hydrophobically cross-linked polymer chains. Here the micelles of EHDDAB had two functions, first they uniformly dispersed the Zn-MOFs and secondly they dynamically cross-linked the polymer chains, profoundly influencing the mechanical characteristics of the hydrogels. The non-covalent synergistic interactions introduced by Zn-MOFs endowed the hydrogels with the capacity for high stretchability, high stress, rapid self-recovery, anti-fatigue properties, and conductivity, all achieved without external stimuli. Furthermore, hydrogels based on Zn-MOFs can serve as durable and highly sensitive flexible transducers, adept at detecting diverse mechanical deformations with swift response-recovery times and high gauge factor values. Consequently, these hydrogels can be tailored to function as wearable strain sensors capable of sensing significant human joint movements, such as wrist bending, and motions involving the wrist, fingers, and elbows. Similarly, they excel at monitoring subtle human motions, such as speech pronunciation, distinguishing between different words, as well as detecting swallowing and larynx vibrations during various activities. Beyond these applications, the hydrogels exhibit proficiency in distinguishing and reproducing various written words with reliability. The Zn-MOF-based hydrogels hold promising potential for development in electronic skin, medical monitoring, soft robotics, and flexible touch panels.

Robust controllers for a flexible satellite model

We consider a PDE-ODE model of a flexible satellite that is composed of two identical flexible solar panels and a center rigid body. We prove that the satellite model is exponentially stable in the sense that the energy of the solutions decays to zero exponentially. In addition, we construct two internal model based controllers, a passive controller and an observer based controller, such that the linear and angular velocities of the center rigid body converge to the given sinusoidal signals asymptotically. A numerical simulation is presented to compare the performances of the two controllers.

Energy efficiency assessment of alternative power supply system for isothermal wagon for live fish transportation

The research object is the power supply system of isothermal car for live fish transportation. The aim of the work is to assess the reduction of total energy costs when supplying electricity to an isothermal wagon for live fish transport by alternative sources in the form of wind turbines and solar panels. It is proposed to use centrifugal and centripetal wind turbines with vertical rotor as sources of mechanical energy of the aeration system of water tanks with live fish, and flexible solar panels placed on the roof of the isothermal wagon and thermoelectric converters as additional sources of electrical energy. When calculating the total energy costs for supplying electric power to the isothermal wagon for live fish transport, data from the literature sources were used. According to the calculations, by adding alternative sources of electricity to the existing isothermal wagon power supply system for fish transport, the total energy costs can be reduced by more than 30%.

Merger and Acquisition in the Banking Industry a Dynamic Treatment Effect Identification with Flexible Panel Difference- in- Differences Approach

Merger and Acquisition in the Banking Industry a Dynamic Treatment Effect Identification with Flexible Panel Difference- in- Differences Approach

Large-Area Flexible Perovskite Light-Emitting Diodes Enabled by Inkjet Printing.

Metal halide perovskite light-emitting diodes (PeLEDs) are attracting increasing attention due to their potential applications in flat panel lighting and displays. The solution process, large-area fabrication, and flexibility are attractive properties of PeLEDs over traditional inorganic LEDs. However, it is still very challenging to deposit uniform perovskite films on flexible substrates using a blade or slot-die coating, as the flexible substrate is not perfectly flat. Here, the inkjet printing technique is adopted, and the key challenges are overcome step-by-step in preparing large-area films on flexible substrates. Double-hole transporting layers are first used and a wetting interfacial layer to improve the surface wettability so that the printed perovskite droplets can form a continuous wet film. The fluidic and evaporation dynamics of the perovskite wet layer is manipulated to suppress the coffee ring effect by solvent engineering. Uniform perovskite films are obtained finally on flexible substrates with different perovskite compositions. The peak external quantum efficiency of the inkjet-printed PeLEDs reaches 14.3%. Large-area flexible PeLEDs (4×7 cm2 ) also show very uniform emission. This work represents a significant step toward real applications of large-area PeLEDs in flexible flat-panel lighting.

Photothermoelectric Synergistic Hydrovoltaic Effect: A Flexible Photothermoelectric Yarn Panel for Multiple Renewable-Energy Harvesting.

The human body is in a complex environment affected by body heat, light, and sweat, requiring the development of a wearable multifunctional textile for human utilization. Meanwhile, the traditional thermoelectric yarn is limited by expensive and scarce inorganic thermoelectric materials, which restricts the development of thermoelectric textiles. Therefore, in this paper, photothermoelectric yarns (PPDA-PPy-PEDOT/CuI) using organic poly(3,4-ethylenedioxythiophene) (PEDOT) and inorganic thermoelectric material cuprous iodide (CuI) are used for the thermoelectric layer and poly(pyrrole) (PPy) for the light-absorbing layer. With the introduction of PPy, the temperature difference of the photothermoelectric yarn can be increased for a better voltage output. Subsequently synergizing the photothermoelectric effect with the hydrovoltaic effect to create higher electric potentials, a single wet photothermoelectric yarn obtained by preparation can be irradiated under an infrared lamp at a voltage of up to 0.47 V. Finally, the photothermoelectric yarn PPDA-PPy-PEDOT/CuI was assembled in a series and parallel to obtain a photothermoelectric yarn panel, which was able to output 41.19 mV under an infrared lamp, and the synergistic photothermoelectric and hydrovoltaic effects of the photothermoelectric panel were tested outdoors on human body, and we found that the voltage was able to reach approximately 0.16 V under sunlight. Therefore, the voltage values obtained from the photothermoelectric yarns in this study are competitive and provide a new research idea for the study of photothermoelectric yarns.

Reduction of Flow-Induced Trailing Edge Noise of Semi-Infinite Flat Plate by Structural Resonance

A unique method for the reduction in flow-induced trailing edge noise scattering for a semi-infinite thin plate is proposed by utilizing short flexible panels mounted on the surface of the plate. The proposed configuration differs from conventional cantilevered elastic trailing edges due to the limitations of their structural integrity and applicability. The key idea is to design short panels that vibrate in structural resonance under the fluid loading for absorbing the energy from the flow to sustain their vibration. A time-domain direct aeroacoustic simulation coupled with structural dynamics is carried out at a low Reynolds number of 50,000 to explore the aeroacoustic-structural interactions. The effectiveness of noise reduction of the designed configuration is analyzed by comprehensive aeroacoustic analysis where a significant noise reduction is observed for the plate mounted with three flexible panels without any adverse effects on the plate aerodynamics. The structural analysis shows a systematic vibration pattern for all the panels which clearly indicates the presence of complex fluid-structural interaction under resonance conditions. Design strategy of the proposed configuration along with its limitations are also discussed.

Improvement of the low-frequency sound insulation performance of hollow double-leaf panels by inserting a bending panel

Air-borne sound transmission loss of building materials generally follows the mass law. Transmission loss decreases at lower frequencies and is minimal at the fundamental natural frequency f0. On the other hand, transmission loss increases below f0, and is controlled by stiffness. Moreover, the stiffer the materials, the higher the f0. In the other words, even without increasing the mass, increasing the stiffness can improve low-frequency transmission loss. We focus on the fact that flexible lightweight panels are easily stiffened by bending deformation. We conduct a basic study on the effect of inserting a bending panel into hollow double-leaf panels. Experimental results on single panels showed a correspondence between the increase of f0 by bending deformation and the improvement of low-frequency sound insulation performance. In the case of the double-leaf panels with the lightweight bending panel inserted inside, the stronger the bending, the more low-frequency sound insulation performance tended to be improved.

Optimal design for a perforated panel absorber combined with Helmholtz-resonance and plate vibration

This study proposes a perforated panel sound absorber combined with Helmholtz-resonance and plate vibration and its optimal design method to broaden the sound absorption characteristics. The proposed perforated absorber has a simple structure consisting of a flexible panel with a hole and an air cavity. The conventional optimal design theory of the dynamic vibration absorber is applied to the perforated absorber. The proposed absorber is designed so that the acoustic impedance density will be equalized and almost minimized at two points independently of the damping of the panel. Optimal parameters are related to the Helmholtz-resonance frequency, the natural frequency of the panel, and the loss factor of the panel. The absorber with the optimal parameters was fabricated, and the sound absorption coefficient was measured using an acoustic impedance tube. The experimental results shows that the proposed method can effectively design the perforated panel absorber with the broadband sound absorption characteristics.

Design and fabrication of eco - friendly solar scooter from electric scooter

Solar energy, a renewable source of energy, is an imminent form that, if properly used, can give rise to incredible energy that can be further used in different forms. Research is still in progress on applications like solar-powered automobiles, solar-powered steam turbines, etc. The concept of the design and fabrication of solar-powered scooters was mainly intended for the reduction of non-renewable energy consumption and environmental protection. In this connection, it is essential to design and develop an eco-friendly solar-powered vehicle. This is an electric vehicle powered by solar energy obtained from solar panels on the surface of the vehicle, and it works on the principle of the photoelectric effect. Solar vehicles aren't practical day-to-day transportation vehicles at present, but they are used as primary demonstration vehicles. In our work, a Li-ion battery is an energy storage device that can store charge from a flexible monocrystalline solar panel. A brushless DC hub motor is the prime mover, and it drives the vehicle with the support of two wheels. A solar charge controller is used to manage the charging of a battery bank and control the ratio of current and voltage. This solar electric scooter has the capability to carry weights up to 150 kg and can travel at speeds of 40 km/h. The developed solar scooter can provide an incessant journey of 7 km, or it can travel up to 3 hours continuously. It is designed to be user-friendly, free from pollution, and entirely different from conventional vehicles. This solar powered vehicle solves various problems related to the environment, and it is the most efficient pollution-free technique.

On improving low-frequency sound absorption using a compound microperforated panel backed by a panel-type resonator with tuned multi-frequency resonators

The present work is aimed to broaden the half-absorption bandwidth and improve low frequency sound absorption of a microperforated panel (MPP) by investigating the effects of tuned multi-frequency resonators attached to a flexible panel (i.e. a multi-frequency panel resonator – mMPR), as the backing of MPP so to create a compact sound absorber. The effects of different configurations of multi-frequency resonators were investigated through theoretical and experimental studies. The results demonstrated that the coupling strength among MPP, the panel and resonators at their resonant frequencies had a significant contribution to shaping the sound absorption characteristics, that were particularly influenced by the placement of resonators, quantity of resonators and the configuration of resonators, and these parameters could be tuned to extend the half-absorption bandwidth as well as the low frequency sound absorption coefficient. It was found that there was minimal mass of resonators for them to be effective in improving low frequency sound absorption characteristics and an optimal mass ratio demonstrated a better sound absorption performance in terms of bandwidth and absorption coefficient without an unnecessary increase of structural mass. A circular arrangement of multi-resonators was found to be beneficial in achieving relatively similar MPP-panel-resonator coupling of multi-resonators so to achieve a more uniform sound absorption coefficient within the particular bandwidth. It was experimentally demonstrated that a 200 mm × 200 mm MPP with the backing of a panel and circularly-arranged multi-frequency resonators of only 2 % mass ratio, could achieve a wide low-frequency half-bandwidth from 160 Hz to 550 Hz with the averaged absorption coefficient improved by 18 % to 0.72 over 150 Hz to 260 Hz, in the frequency range within which the absorption valley was previously located.

Flutter and Limit-Cycle Oscillations of a Panel Using Unsteady Potential Flow Aerodynamics

The potential aerodynamic theory is implemented to model the flow over a flexible panel. The present study compares the more complete unsteady version of the potential flow theory with its simplification known as the linear piston theory for different Mach numbers and the two- and three-dimensional aerodynamic models. The piston theory is “local” in space and time because it assumes the pressure at a spatial point and time only depends on the panel deformation at the same point and time. The full potential flow model includes the effect of the past history of the panel deformation and the spatial distribution of the panel deformation on the pressure at any instant in time and at any point in space. Aeroelastic analysis is made to trace the flutter onset critical condition based on the limit cycle oscillation amplitudes, and the results are compared with the more traditional implementation using piston theory. Conclusions are made based on the use and application of this more complete aerodynamic theory, particularly for near-transonic and hypersonic flow regimes. Subsonic results are also presented in this study.

B-149 Next-generation Sequencing Via Targeted Metagenomics for Broad Antimicrobial Resistance Surveillance

Abstract Background Antimicrobial-resistant infections secondary to the overuse of antibiotics are a major public health threat. The standard of care for identifying resistance is antimicrobial susceptibility testing, the phenotypic characterization of minimum inhibitory concentrations (mic) for antibiotics in the presence of bacterial growth, but these methods are labor intensive, have long turnaround times, and face challenges with non-cultivable bacteria. Molecular methods for antimicrobial resistance (AMR) ascertainment are high-throughput, robust, and sensitive and have gained interest as a genotypic complement to traditional phenotypic methods. Since the COVID-19 pandemic, next-generation sequencing has emerged as the leading technology for tracking and surveillance of infectious diseases and antimicrobial resistance, emphasizing the need for flexible sequencing panels that are easily interchangeable and capable of detecting pathogens and AMR genes. Methods In a collaboration between Illumina, a national retail pharmacy, and Aegis Sciences Corporation, residual, self-collected nasal swab samples (n = 4390) submitted for COVID-19 testing from patients across the U.S. were sequenced using the Respiratory Pathogen ID/AMR Panel (RPIP, Illumina – For Research Use Only), a target capture-based next-generation sequencing panel targeting 282 respiratory pathogens and 2097 relevant AMR markers. Sequencing data was analyzed using the Explify RPIP Analysis app (BaseSpace, Illumina) and paired with self-reported patient data submitted via an online questionnaire. Data including pathogens and anti-microbial resistance (AMR) genes detected, age, race, gender, residing state of the patient, collection month, self-reported symptoms, and health risks were collated, imported into Microsoft PowerBI software, and used to create interactive visuals for a surveillance dashboard. Results In this cohort of sequenced specimens, 85.1% (n = 3576) had one or more viral, bacterial, or fungal pathogens present, 41% (n = 1816) had one or more AMR genes present, and 38.4% (n = 1685) had one or more pathogens and AMR genes co-detected. Twenty-six different AMR genes were identified with the most prevalent being Erm 23S ribosomal RNA methyltransferase (65.5%; n = 1115). Erm was identified in samples from all 50 US states and was co-detected with staphylococcus aureus (18.2%; n = 216) and streptococcus pneumoniae (4.9%; n = 57), among others. Following Erm in prevalence, this cohort of samples harbored genes for trimethoprim resistant dihydrofolate reductase (dfr = 27.9%), tetracycline-resistant ribosomal protection protein (tet = 21.0%), and macrolide phosphotransferase (MPH = 14.2%). The data also revealed AMR gene-pathogen co-detections listed as CDC serious threats, such as the mecA gene responsible for methicillin resistance in staphylococcal species. The mecA gene was co-detected in 5.3% (n = 28) of staphylococcus aureus positive samples in this cohort. Finally, although not classified as a serious threat, neuraminidase inhibitor resistance, associated with less susceptibility to anti-virals, was found in 12% (n = 15) of all influenza A (H3N2) infected samples (n = 112). Conclusions Completion of these studies demonstrated that next-generation sequencing using targeted metagenomics with RPIP is a cost effective, high-throughput option for large-scale surveillance of AMR genes in potential respiratory infections.

Personalized Cancer Monitoring Assay for the Detection of ctDNA in Patients with Solid Tumors.

Highly sensitive molecular assays have been developed to detect plasma-based circulating tumor DNA (ctDNA), and emerging evidence suggests their clinical utility for monitoring minimal residual disease and recurrent disease, providing prognostic information, and monitoring therapy responses in patients with solid tumors. The Invitae Personalized Cancer Monitoring™ assay uses a patient-specific, tumor-informed variant signature identified through whole exome sequencing to detect ctDNA in peripheral blood of patients with solid tumors. The assay's tumor whole exome sequencing and ctDNA detection components were analytically validated using 250 unique human specimens and nine commercial reference samples that generated 1349 whole exome sequencing and cell-free DNA (cfDNA)-derived libraries. A comparison of tumor and germline whole exome sequencing was used to identify patient-specific tumor variant signatures and generate patient-specific panels, followed by targeted next-generation sequencing of plasma-derived cfDNA using the patient-specific panels with anchored multiplex polymerase chain reaction chemistry leveraging unique molecular identifiers. Whole exome sequencing resulted in overall sensitivity of 99.8% and specificity of >99.9%. Patient-specific panels were successfully designed for all 63 samples (100%) with ≥20% tumor content and 24 (80%) of 30 samples with ≥10% tumor content. Limit of blank studies using 30 histologically normal, formalin-fixed paraffin-embedded specimens resulted in 100% expected panel design failure. The ctDNA detection component demonstrated specificity of >99.9% and sensitivity of 96.3% for a combination of 10 ng of cfDNA input, 0.008% allele frequency, 50 variants on the patient-specific panels, and a baseline threshold. Limit of detection ranged from 0.008% allele frequency when utilizing 60 ng of cfDNA input with 18-50 variants in the patient-specific panels (>99.9% sensitivity) with a baseline threshold, to 0.05% allele frequency when using 10 ng of cfDNA input with an 18-variant panel with a monitoring threshold (>99.9% sensitivity). The Invitae Personalized Cancer Monitoring assay, featuring a flexible patient-specific panel design with 18-50 variants, demonstrated high sensitivity and specificity for detecting ctDNA at variant allele frequencies as low as 0.008%. This assay may support patient prognostic stratification, provide real-time data on therapy responses, and enable early detection of residual/recurrent disease.

Overview of the Current State of Flexible Solar Panels and Photovoltaic Materials.

The rapid growth and evolution of solar panel technology have been driven by continuous advancements in materials science. This review paper provides a comprehensive overview of the diverse range of materials employed in modern solar panels, elucidating their roles, properties, and contributions to overall performance. The discussion encompasses both traditional crystalline silicon-based panels and emerging thin-film technologies. A detailed examination of photovoltaic materials, including monocrystalline and polycrystalline silicon as well as alternative materials such as cadmium telluride (CdTe), copper indium gallium selenide (CIGS), and emerging perovskite solar cells, is presented. Furthermore, the impact of transparent conductive materials, encapsulation polymers, and antireflective coatings on solar panel efficiency and durability is explored. The review delves into the synergistic interplay between material properties, manufacturing processes, and environmental considerations. Through a comprehensive survey of materials utilized in modern solar panels, this paper provides insights into the current state of the field, highlighting avenues for future advancements and sustainable solar energy solutions.