Side Of Panel Research Articles

Programming the mechanical properties of double-corrugated metamaterials by varying mountain-valley assignments.

Origami metamaterials have gained significant attention in recent years, with extensive analysis conducted on their mechanical properties. Previous studies have primarily focused on the effects of design angles, panel side lengths, folding angles or other geometric and material parameters. However, mountain-valley crease assignments of origami patterns, which significantly effect both the geometric and mechanical properties, have yet to be studied in depth. In this article, we create a series of double-corrugated metamaterials with diverse mountain-valley assignments and analyse their Poisson's ratios and mechanical properties under compression loading. The findings of our study demonstrate that varying the mountain-valley assignments allows for the construction of metamaterials with consistent or distinct Poisson's ratios. These assignments have the capability to program the magnitude and to vary the rate of the folding angles. Furthermore, the mechanical properties of the corresponding metamaterials, in particular the specific energy absorption (SEA) and normalized stiffness, exhibit positive correlations with the respective folding angles. Our study highlights the significance of varying mountain-valley assignments as a promising approach for designing origami metamaterials and programming their mechanical properties.This article is part of the theme issue 'Origami/Kirigami-inspired structures: from fundamentals to applications'.

Effects of Acute and One-Week Supplementation with Montmorency Tart Cherry Powder on Food-Induced Uremic Response and Markers of Health: A Proof-of-Concept Study

Metabolic conditions, such as gout, can result from elevated uric acid (UA) levels. Consuming high-purine meals increases UA levels. Therefore, people with hyperuricemia typically must avoid ingesting such foods. Polyphenols have been shown to reduce uric acid levels and tart cherries (TCs) are a rich source of phenolic and anthocyanin compounds. This proof-of-concept study evaluated whether ingesting TCs with a purine-rich meal affects the uricemic response. Methods: A total of 25 adults (15 males and 10 females, 85.0 ± 17 kg, 40.6 ± 9 years, 29.1 ± 4.9 kg/m2) with elevated fasting UA levels (5.8 ± 1.3 mg/dL) donated a fasting blood sample. In a randomized, double-blind, crossover, placebo-controlled, counterbalanced manner, participants ingested capsules containing 960 mg of a placebo (PLA) or concentrated TC powder containing 20.7 mg of proanthocyanins with a serving of hot soup (10 g of carbohydrate, 2 g protein, and 1 g fat) containing 3 g of purines (1 g of adenosine 5′-monophosphate, 1 g of disodium 5′-guanylate, and 1 g of disodium 5′-inosinate). Blood samples were obtained at 0, 60, 120, 180, and 240 min after ingestion to assess changes in uric acid levels and pharmacokinetic profiles. Cell blood counts, a comprehensive metabolic panel, cytokines, inflammatory markers, and subjective side effects ratings were analyzed on baseline (0 min) and post-treatment (240 min) samples. Participants continued consuming two capsules/day of the assigned treatment for one week and then repeated the experiment. Participants observed a 14-day washout and then repeated the experiment while ingesting the alternate treatment. Data were analyzed using general linear model (GLM) statistics with repeated measures, pairwise comparisons, and percentage change from baseline with 95% confidence intervals (CIs). Results: No statistically significant interaction effects or differences between treatments were seen in uric acid levels or PK profiles. Analysis of percent changes from baseline revealed that TC ingestion reduced the blood glucose levels following the ingestion of the high-purine meal (−4.2% [−7.7, −0.7], p = 0017). Additionally, there was some evidence that TC ingestion attenuated the increase from baseline in IL-1β and IL-10 and increased INF-γ. No significant differences were seen in the remaining health markers or subjective side effects ratings. Conclusions: Acute and one-week TC supplementation did not affect the uricemic response to ingesting a high-purine meal in individuals with mildly elevated UA levels. However, there was some evidence that TC supplementation may blunt the glycemic response to ingesting a meal and influence some inflammatory cytokines. Registered clinical trial NCT04837274.

Experimental study on the flexural performance of concrete hollow composite slabs with tightly connected panel sides

The performance of joint connections in composite slabs is crucial for ensuring their bidirectional load-bearing capacity and overall structural integrity. To effectively address the challenge of protruding rebar in precast components, a new structural form of a tightly connected hollow concrete composite slab without protruding rebar on the slab side is proposed. To investigate the mechanical performance and failure modes of this slab-side tight-joint connected hollow concrete composite slab, bending performance tests under monotonic load were conducted on three tightly connected hollow composite slabs and one seamless hollow composite slab. The analysis focused on the failure modes, crack distribution, bending capacity, and bending stiffness of additional steel bars at the joints of the slabs. The results indicate that, under normal operating conditions, the flexural performance development of concrete hollow composite slabs with tightly connected slab sides is generally consistent with that of the non-spliced cast hollow composite slab. Under ultimate conditions, tearing or brittle fracture failure at the joint interface is likely to occur in the composite slabs, leading to a reduction in flexural bearing capacity. With an increase in joints, the bending capacity of the hollow composite slab decreases by 17.1%, Conversely, when joints are positioned away from the most stressed section, the flexural stiffness of the section increases by 13.5%. A comparison of experimental data and theoretical calculations indicates that the additional rebar at the joints effectively contributes to the lateral load transfer in the hollow composite slab, achieving bidirectional load-bearing capacity. This further validates that the design of the single-joint, tight-joint connected hollow concrete composite slab without protruding rebar meets the requirements for bidirectional load-bearing performance.

DeepQR: single-molecule QR codes for optical gene-expression analysis

Abstract Optical imaging and single-molecule imaging, in particular, utilize fluorescent tags in order to differentiate observed species by color. The degree of color multiplexing is dependent on the available spectral detection window and the ability to distinguish between fluorophores of different colors within this window. Consequently, most single-molecule imaging techniques rely on two to four colors for multiplexing. DeepQR combines compact spectral imaging with deep learning to enable 4 color acquisition with only 3 spectral detection windows. It allows rapid high-throughput acquisition and decoding of hundreds of unique single-molecule color combinations applied here to tag native RNA targets. We validate our method with clinical samples analyzed with the NanoString gene-expression inflammation panel side by side with the commercially available NanoString nCounter system. We demonstrate high concordance with “gold-standard” filter-based imaging and over a four-fold decrease in acquisition time by applying a single snapshot to record four-color barcodes. The new approach paves the path for extreme single-molecule multiplexing.

Electrical and thermal performance of bifacial photovoltaics under varying albedo conditions at temperate climate (UK)

Bifacial photovoltaics (bPV) provide an advantage over their traditional monofacial counterparts as they can utilise solar radiation incident on both the front and rear side of the module, allowing for increased energy production. While this is an advantage on the side of bPV, the amount of energy produced by the rear side of the bPV panel can vary greatly depending on the inclination and azimuth of the panel as well as external climatic and ground albedo conditions. This paper aims to analyse the electrical and thermal performance of bPV under varying albedo conditions, using two different materials: grass, and a reflective material. It also contains an example of bifaciality testing under real-world conditions. Several experiments were conducted to evaluate the electrical performance and the temperature distribution of the bPV panel under different weather conditions at the UK location and then the results were compared with the single diode model of bPV. Furthermore, a bPV panel temperature model has been developed for the temperate climate condition of UK. The results show that the open circuit voltage of the system increases with irradiance up to around 800 W/m2, at which point it decreased due to the increased PV system temperature. The normalised efficiency for the PV system under different conditions were also evaluated, which showed that the bPV module was most efficient under diffuse irradiance conditions, encouraging the use of the bPV technology in the UK.

Uniform Lighting of High-Power LEDs at a Short Distance to Plants for Energy-Saving and High-Density Indoor Farming

A tunable LED panel with multiple types of LEDs on a panel can provide various spectra for optimal plant growth. However, it is difficult for a lighting panel with multiple types of high-power LEDs to achieve uniform lighting. We demonstrated that by using optical reflectors at the sides of an LED panel to trap photons of LED arrays or using both the above-mentioned reflectors and optical lenses on each LED, high lighting uniformity can be achieved at a short distance to plants. The ray tracing simulation results show that the LED panel equipped with reflectors and optical lenses can achieve a high uniformity of >0.80 when the LED-plant distance is at half of the LED array’s pitch. We further verified that an LED panel (at a size of 88 cm × 54 cm) installed with reflectors can achieve light uniformities around 0.90 at a 15 cm LED-plant distance for the 6 types of LEDs (4 color LEDs and 2 white LEDs) on the panel. Compared with a branded tunable LED panel, our LED panel saves >25 cm vertical distance for each tier of plants and has 92.5% higher photon efficacy for 660 nm LEDs that exist on both panels.

Quantitative modeling and validation of the impact of border dust on photovoltaic panels: A piecewise single diode approach

Dust accumulation at the border of photovoltaic (PV) panels significantly reduces the power, safety, and economy of PV power generation. However, no quantitative model of the power generation of PV panels with border dust exists. A piecewise single-diode model (SDM) is used to establish a PV power generation model that considers border dust accumulation. The influence of the dust concentration and dust area on the model parameters is investigated. A numerical solution based on a dynamic initial value is proposed to obtain the voltage and power of PV cells at a fixed current. An experimental platform for border dust deposition is built to verify the model performance. The influence of border dust on the power generation of PV panels is discussed. The results show that border dust accumulation significantly reduces the power generation of PV cells. The power loss is 60.13 W (63.30 W) when the border on the PV panel’s short (long) side is covered with 36 g/m2 of sandy soil. Moreover, the impact of dust on the PV power generation differs for dust in different locations. The power loss increases with an increase in the dust concentration and dust area when the dust is on the border of the PV panel’s short side. In contrast, due to bypass diode protection, when dust is on the long side of the PV panel, the power loss will increase and then stabilize as the dust concentration increases. The dust type also affects the PV power generation ability. At the same dust level and location, the power loss is the largest for cement, followed by sandy soil and red soil.

Fabrication of antireflective superhydrophobic coating for self-cleaning solar panels and study of energy efficiency

Dust accumulation on solar panels decreases its efficacy due to the reflection of radiation by dust particles, which further decreases the amount of radiation reaching the solar cells. Antireflective superhydrophobic coatings based on nano-silica and nano-titania were prepared and applied on glass slides and small solar panels for laboratory scale study. All the coated substrates showed hydrophobic to superhydrophobic nature as confirmed by the contact angle of water drops on the coated glass. Scanning electron microscopy and atomic force microscopy results confirmed the presence of nanostructures on coated surfaces, which was responsible for the superhydrophobic behavior. The coating was also found to be stable in acidic, neutral, and basic solutions and a slight change in contact angle was observed after dipping the coated glass in different pH solutions. The antireflective nature of coated solar panels was also observed, and it was found that the coated side of the solar panel showed less reflection of light compared to the uncoated side. The current–voltage curve (I–V curve) was plotted for uncoated and coated solar panels and, further, fill factor and efficiency were calculated. Dust repelling and cleaning efficiency were also evaluated, and it was found that different types of dust were easily removed from coated panels without leaving behind any scratch marks. From the results, it can be concluded that the antireflective and superhydrophobic coatings are simple and sustainable solutions for cleaner and more efficient solar panels.

Energy and exergy analysis with cost-efficiency comparison of modified phase change material (PCM) integrated with solar panel thermal system

This study investigates the efficiency and cost-effectiveness of integrating Phase Change Materials (PCMs) into solar panels to optimize power output and power conversion efficiency under varying temperature conditions. By applying PCMs, temperature fluctuations can be reduced, maintaining solar panels at an optimal temperature for power generation. The research employs modeling and simulation techniques, focusing on energy and exergy analysis of solar energy storage systems based on pure and modified PCMs such as Paraffin wax, Sodium acetate trihydrate, Sodium sulfate decahydrate, etc. Temperature and light intensity data are collected in the Wangchan district, Rayong province, using a light intensity sensor and a thermocouple. The study analyzes each layer of the solar panel, employing numerical methods and matrix solutions to solve the system of non-algebraic equations, yielding temperature values for each component layer. The thermodynamic properties of the modified PCMs are calculated theoretically, and their cost-efficiency is analyzed by comparing the solar panel’s increased power area density generation after applying specific PCMs to the cost of the PCM. The simulation results demonstrate that the solar panel integrated with PCM generates up to 11.1% more power than a regular solar panel, assuming negligible heat loss from the sides of the solar panel and an average temperature during the melting and solidification processes for the PCMs. Moreover, the best cost-efficiency of the modified PCM is achieved, with an increase of up to 637.7%, using a combination of paraffin wax and polyethylene glycol.

The Performance Evaluation of Photovoltaic Integrated Organic Phase Change Material in a Single Container using Indoor Solar Simulator

Photovoltaic panels convert sunlight, a renewable energy source, into electrical energy. The abundant irradiance will heat the photovoltaic panel, reducing the panel's efficiency. This study proposes using PCM 36 as a cooling technique to reduce the temperature of the photovoltaic panel, which is low-cost and has higher latent heat capacity. The indoor solar simulator study is performed to meet the IEC 60904-9 standard. The research process starts with validating PCM 36, sun simulator testing, validating the photovoltaic panel, and fabricating a container to place the PCM 36 at the rear side of the photovoltaic panel to cool down the temperature. The final experiments are conducted indoors, using three different irradiance levels and a one-hour photovoltaic panel operation under the sun simulator. The optimal results reveal a 31.67% reduction in temperature and a 6.83% increase in electrical efficiency at a maximum of 40 minutes, 500 W/m2 irradiance, with a 9 mm thickness of PCM 36. Throughout this study, the efficiency of the photovoltaic system is enhanced by effectively reducing the temperature within the optimal range by incorporating phase change material.

Asymmetrical distribution of roof microseismicity and its application to roof control of a deep longwall panel

Deep mining is widely carried out across the world. Due to large cover depth, both stress magnitude and fracture development are greatly enlarged, increasing the complexity in mining conditions. Correspondingly, a series of ground control problems emerge in deep coal mines, such as face collapsing, roof falling and support jamming. This study mainly focusses on the variation in roof activity along face length direction, which helps to strengthen roof control of a deep longwall panel. Geological radar detection reveals that the development of mining-induced fractures present an increasing trend from the maingate to tailgate side, implying the variation in roof activity along face length direction. Microseismic (MS) monitoring is moreover conducted, with which both spatial distribution and dynamic evolution of MS events in roof strata are thoroughly analyzed. Due to stronger influence provided by fault structures, the concentration of MS number mainly occurs to the tailgate section. Thus, roof microseismicity is brisker in the referred section, accounting for 63.7% of the total events. The sensitivity of MS energy to fault structures is weaker than that of MS number. Energy concentration can be observed in the whole panel width. In the maingate section, the energy proportion reaches 44.1%, indicating stronger roof microseismicity. Such asymmetrical distribution in roof microseismicity is sensitive to fault activation, fracture influence and mining disturbance. The location of fault structures, spatial variation in fracture parameters and the difference in stress rotation characteristics contribute to asymmetrical distribution in roof microseismicity on two sides of the target panel. Based on MS characteristics, a coordinative movement method is innovatively proposed for hydraulic supports, which weakens cyclic disturbance of support movement on roof strata at the face area. The method is proved to be effective by the improvement in roof stability and mining efficiency.

Experimental investigation and performance evaluation of spiral and serpentine collectors based photovoltaic thermal system in Peninsular Malaysia

Photovoltaic thermal (PVT) systems have been developed for nearly five decades as a further development of PV technology. The PVT system was designed to overcome the limited space for PV and solar water heaters and improve PV cell performance. However, many studies on PVT are theoretical and modeling, so experimentation is needed to confirm it. This study investigated the performance of PVT systems with a spiral and serpentine thermal collector without metal sheets in two scenarios, without and with insulation. Commercial PV was modified with the addition of a copper tube thermal collector and tested with a comparison PV under the weather of the Malaysian peninsula. The experimental results show a maximum electrical efficiency enhancement of 0.53% and a decrease in module temperature up to 5.60 °C in scenario 1. Also, the addition of insulation in scenario 2 increases thermal efficiency up to 18.26%, even though it causes a decrease in electrical efficiency. This research shows that an uncomplicated thermal collector is adequate to increase the electrical efficiency of PV panels. In contrast, the addition of insulation in the rear side of the PVT panel increases the thermal performance of PVT systems.

Scientific Approaches to Solving the Problem of Joint Processes of Bubble Boiling of Refrigerant and Its Movement in a Heat Pump Heat Exchanger

The joint processes of bubble boiling and refrigerant movement in heat pump tubes are considered. A coil located on the back side of the photovoltaic panel (PVP) is used as an additional heating surface. A mathematical model of the theoretical determination of the temperature on the front surface of the PVP cooled by freon in the coil from the back side has been created. A feature of the numerical simulation of bubble boiling of refrigerant in a coil was the insufficiently detailed study of the process and the lack of references to the results obtained in earlier work. The authors have clarified the boundary conditions and assumptions for numerical simulation of the bubble boiling process of refrigerant R407C. The results were compared with the theoretically found values, and later used in the design of an energy complex consisting of a heat pump and a photovoltaic panel. The mathematical model of theoretical calculation of the PVP temperature and the methodology for constructing a numerical model of bubble boiling of refrigerant as part of the methodology for designing energy technology complexes based on the authors’ plan to present a unified methodology for energy technology complexes for desalination of seawater based on other types of renewable energy sources.

Experimental Evaluation of PV Panel Efficiency Using Evaporative Cooling Integrated with Water Spraying

In this work, an inventive photovoltaic evaporative cooling (PV/EC) hybrid system was constructed and experimentally investigated. The PV/EC hybrid system has the prosperous advantage of producing electrical energy and cooling the PV panel besides providing cooled-humid air. Two cooling techniques were utilized: backside evaporative cooling (case #1) and combined backside evaporative cooling with a front-side water spray technique (case #2). The water spraying on the front side of the PV panel is intermittent to minimize water and power consumption depending on the PV panel temperature. In addition, two pad thicknesses of 5 cm and 10 cm were investigated at three different water flow rates of 1, 2, and 3 lpm. In Case #1, the evaporative cooling decreased the temperature of the PV panel by about 15 ℃ related to the uncooled PV panel for both pad thicknesses. While case #2 showed a more significant temperature drop for PV panel by about 27 ℃ and 29.7 ℃ for pad thicknesses of 5 cm and 10 cm, respectively. Compared to the uncooled PV panel, the cooled panel had a distinct enhancement in performance. The efficiency of the PV panel in case #1 was augmented by 5.7% with 50 mm pad thickness and 8.4% for 100 mm pad thickness. Case #2 revealed more improvement in the efficiency by 9% for 5 cm and up to 20% for 10 cm pad thickness. The PV panel electric power was augmented by 7.3% and 13.8% for 2 and 3 lpm water flow rates, respectively. Compared to the flow rate of 1 lpm. The open voltage circuit improved by 4.1% and 9.4% for cases #1 and #2, respectively. The higher air temperature drop was about 11.4 ℃ for case #2 at 10 cm pad thickness.

Highly porous copper foam coated with graphene flakes and silver nanowires to cool overheated solar air heaters

Solar air heaters (SAHs) transfer radiative heat to the air flowing under irradiated panels. However, excessive heating can induce thermal stresses and cause malfunctioning of solar devices. Thus, a method to cool the panels is essential. We developed a highly effective method for cooling an overheated solar collector panel by increasing the surface area using a highly porous metal foam supersonically sprayed with graphene flakes (G) and silver nanowires (AgNWs). Notably, convective cooling via the textured surface only reduced the surface temperature without affecting the total amount of solar heat collected at the radiated side. The effect of G/AgNW texturing and the highly porous metal foam on cooling was assessed. The best G/AgNW-coated foam afforded a temperature reduction of ΔT = 18 °C and a 25.3% increase in heff compared with the bare case. In addition, G/AgNW texturing significantly increased the amount of solar heat collected, with a temperature increase of ΔT = 81 °C, because the G/AgNW surface promoted the trapping of radiative heat waves, similar to the perfect black body of a Helmholtz jar. Therefore, augmentation with a G/AgNW layer is recommended for both the solar heat collecting and convective cooling sides of an SAH panel.

The imaginary part of the diffuse field forced normalized radiation impedance of a rectangular panel

This paper modifies previous approximate formulae for calculating the imaginary part of the azimuthally averaged forced normalized radiation impedance experienced on one side of a rectangular panel mounted in an infinite rigid plane baffle by a forced travelling wave on the rectangular panel which is excited by an infinite plane sound wave incident at an angle to the normal to the rectangular panel on one side of the rectangular panel. This modification is made so that the formulae can be analytically integrated over all possible solid angles of incidence on one side to obtain formulae for the imaginary part of the diffuse sound field forced normalized radiation impedance of the rectangular panel. The paper also gives existing formulae for the real part of this diffuse sound field forced normalized radiation impedance. The reason for developing approximate formulae for the imaginary part of this diffuse sound field forced normalized radiation impedance is so that they can be used when approximating the equation for the diffuse field sound transmission coefficient of a limp single leaf wall.

Relationship between the length of panel side and the deflection of sandwich panels with corrugated core

Relationship between the length of panel side and the deflection of sandwich panels with corrugated core

Improving mechanical property and microstucture evolution of 7075 aluminum panel formed by unequal alternate double-sided laser shock forming

With thrust weight ratio increasing, integral panel is an important component to reduce the aircraft weight, and it is a great challenge to ensure the forming accuracy and mechanical property in the large-scale panel. Laser shock forming has a great development prospect in realizing integral panel forming and improving its mechanical properties. This work investigated unequal alternate double-sided laser shock forming, which can make 7075 aluminum panel form and induce the hardened layers in both panel sides. The improvements were analyzed in mechanical properties and microstructure evolution of 7075 aluminum panels after unequal alternate double-sided laser shock forming. In the surface and subsurface layer, the residual stress and microhardness were verified to be enhanced by the laser shock wave. The results of XRD and EBSD provided the evidence of grain refinement. The strengthening mechanism of unequal alternate double-sided laser shock forming was analyzed in this work. The grains are distorted and refined during high strain rate plastic deformation due to dislocation slip and accumulation. The mechanical properties were enhanced by unequal alternate double-sided laser shock forming due to the hardened layers in both panel sides. The hardened layers and grain refinement have a great significance in inhibiting the crack generation and growth.

Analysis of deformation characteristics of flood gates of runoff hydropower stations under different operating conditions in case of frequent floods

The safety and reliability of flood gates of runoff hydropower stations in the basin are very important. There is no clear rule on the mechanical causes of flood gate deformation in runoff hydropower stations under frequent floods. Therefore, this paper takes a hydropower station as the research object, adopts the unidirectional fluid-solid coupling method, and investigates the stress displacement of flood gate under typical frequent flood conditions by using ANSYS and Fluent software. The results show that the maximum stress of the flood gate is located at the intersection of the bottom two sides of the gate panel and the gate pier, and the stress meets the stiffness requirement. When the gate is opened, the stress distribution range of the panel is shifted from the top to the bottom, and the stress decreases with the increase of the gate opening degrees. The maximum total displacement is concentrated at the bottom of the central axis in the direction of the panel span, and gradually decreases from the middle of the gate panel to the left and right sides, showing a fan-shaped distribution, and basically symmetrical along the central axis of the panel. The flood gate is mainly deformed along the downstream direction, with obvious depression characteristics.

The Experimental Investigation of a New Panel Design for Thermoelectric Power Generation to Maximize Output Power Using Solar Radiation

It is well established that renewable energy resources for electricity generation are free. In hot areas, solar energy has become one of the major interests of researchers and specialists. This paper aims to experimentally investigate the maximum voltage generation of a thermoelectric generator (TEG) panel. This panel was built from many TEG modules that are connected in series and in parallel. The panel was exposed to high heat due to solar radiation during summer, either directly or through a Fresnel lens. The other side of the TEG panel was cooled using tap water that was passed through aluminum heat exchangers in an active cooling method. It was found that the maximum open-circuit voltage of this TEG panel using a Fresnel lens was 9.35 V. With no lens, it was 11.75 V at 14:00 h local time. The experiments were done during a sunny July period in Iraq.