Layers Of Foil Research Articles

Exploring alternative manufacturing techniques for high-quality solar cell interconnectors: a comparative study of laser cutting and electric discharge machining

Abstract Solar cell interconnectors are typically crafted from thin foils to establish an electrical connection between two components. For limited production of interconnectors with non-standard dimensions, common production methods (such as stamping and sheet metal processes) cannot be utilized. This article examines alternative techniques, such as Fiber Laser Cutting Machine and Electric Discharge Machining (wire cutting). The laser cutting method did not achieve the desired quality standards, leading to the rejection of the interconnectors. Issues such as burning, local melting, and damage to the silver coating were noted at the edges. The melting of the coating layers formed brittle intermetallic compounds, which can cause cracking and reduce weldability and solderability. In contrast, the Electric Discharge Machining method successfully produces interconnectors with complex shapes by stacking layers of foil. This approach results in high-quality interconnectors that showed no signs of burning or local melting on their edges.

Improving the building's thermal performance by using untraditional building blocks

AbstractIraqi buildings consume high-level electrical energy for air conditioning purposes to provide the standard human comfort condition. This paper adopted an experimental study by using Styrofoam adhesive or white cement as an alternative to ordinary Portland cement to manufacture building blocks with dimensions of 200 × 200 × 200 mm containing an internal core with dimensions of 90 × 130 × 130 mm, which were filled by using corrugated scratch-up or closed air gap. The samples were divided into two sets: the first had an aluminium foil layer applied to the external surface of the samples (reflective surface), while the second was without any layer (ordinary surface). The samples were tested under the climatic conditions of Baghdad city during the summer months (May to September) of 2021. These blocks were also evaluated by different structural tests. It can be seen from the test results that the use of Styrofoam adhesive with a reflective surface with panels of corrugated scratch-up increased the thermal insulation of the wall. It leads to reduce thermal leakage and the electrical energy consumed to provide comfortable thermal conditions by 52.7%, in addition to decreasing the mass density by 14.1% while compressive strength decreased by 21%.

Characterization of Micro-Holes Drilled Using a UV Femtosecond Laser in Modified Polyimide Flexible Circuit Boards.

Modified polyimide (MPI) flexible printed circuits (FPCs) are used as chip carrier boards. The quality of the FPC directly affects the reliability of the integrated circuit. Furthermore, micro-holes are critical components of FPCs. In this study, an ultraviolet (UV) femtosecond laser is used to drill micro-holes in double-layer flexible circuit boards with MPI as the substrate. The morphology of the micro-hole wall in the copper foil and MPI layer is observed, and the effects of the laser processing parameters on the diameter and depth of the micro-holes are analyzed. The drilling process and mechanism of micro-holes obtained using a UV femtosecond laser in MPI FPCs are discussed. The results show that the morphology of femtosecond laser-machined copper is closely related to the laser energy, and a periodic structure is observed during the machining process. Copper, MPI, and copper oxides are the most common molten deposits in micro-holes during drilling. The depth of the micro-holes increases with an increase in the energy of a single pulse, scanning time, and scanning overlap rate of the laser beam. However, the diameter exhibits no discernible alteration. The material removal rate increased significantly when laser processing was applied to the MPI resin layer.

Structure and Reactivity of Active Oxygen Species on Silver Surfaces for Ethylene Epoxidation.

The epoxidation of ethylene stands as one of the most important industrial catalytic reactions, and silver-based catalysts show superior activity and selectivity. Oxygen is activated on the surface of silver during the reaction and exerts a substantial impact on product selectivity. Notably, the oxygen species residing in the topmost atomic layers profoundly influence the reactivity of a catalyst. However, their characterization under in situ reaction conditions remains a huge challenge, and specific structures have not been identified yet. In this study, we employ in situ X-ray photoelectron spectroscopy and density functional theory calculations to determine the oxygen species formed at the topmost atomic layers of a silver foil and to assign them a structure. Three different groups of oxygen species activated on silver are identified: (i) surface lattice oxygen and two oxygen species originating from associatively adsorbed dioxygen and (ii) top and (iii) subsurface oxygen. Transient in situ photoelectron spectroscopy experiments are carried out to reveal the dynamic evolution and thus reactivity of the different oxygen species under ethylene epoxidation reaction environments. The top oxygen atom from the adsorbed associated dioxygen is the most active. Meanwhile, a frequency-selective data analysis method, developed to process time-resolved data, provides insights into the evolving trends of peak intensities for different oxygen species. The versatility of this method suggests its potential application in future time-resolved characterization studies.

Theoretical and experimental research on static stiffness, performance, and lift-off characteristics of multi-layer gas foil thrust bearings

In this study, a new comprehensive fully coupled elastic-hydrodynamic model is developed for a multi-layer gas foil thrust bearing (GFTB). The interaction effects among the top foil, back board, middle foil, and bottom foil, as well as the Coulomb friction effect, are considered. The stiffness and static characteristics obtained by the experimental and theoretical approaches are in good agreement, which verifies the accuracy of the model. The contribution of each foil layer to the overall stiffness and the load-carrying mechanism are analyzed. Interaction effects of the load, preload, and rotational speed on the static performance are investigated comprehensively. Furthermore, start-stop tests are performed to achieve the lift-off speed, start-up torque, and shut-down torque under various operating conditions.

Orthogonal experiments and bonding analysis of ultrasonic welded multi-layer battery foils and tabs

The motivation for this research stems from the growing demand for solid-phase welding technology to join multilayers metals, particularly in green electric vehicles. Welding of foils and tabs inside battery is a challenging task due to poor joint formation at the interface and low strength. Ultrasonic welding is an efficient, reliable and environmentally friendly bonding method to firmly connect multi-layer copper foils and tabs. Therefore, this is used to achieve electrical bonding within the lithium-ion batteries. This is widely used in production of new energy vehicle batteries. In this work, 40 layers of copper foil were bonded to 0.3 mm nickel-plated copper tabs using ultrasonic metal welding technology. The effect of ultrasonic welding parameters on T-peel strength of joints was systematically investigated by orthogonal experimental design. The maximum T-peel strength of 359.17 N was obtained under optimal parameters (e.g., welding energy 600 J, pressure 0.3 MPa and amplitude 55 %). The variation of welding temperature and amplitude under different welding parameters was measured using infrared thermometer and laser vibrometer. Moreover, the surface, cross-sectional and failure fracture analysis and characterization of specimens with different weld qualities were performed using optical microscopy and scanning electron microscopy (SEM). In addition, the state of Ni layer in cross-section was analyzed using the energy dispersive spectroscopy (EDS) technique after ultrasonic welding. This approach can be straightforward and more appropriate to the development of solid-phase welding method for automotive industry.

Mechanistic insight into the Janus Green B on electrochemical roughening layer of copper foil

This study explores the impact of the electroplating additive JGB the surface characteristics and peel strength of electrolytic copper foils used in printed circuit boards. Utilizing Scanning Electron Microscopy and Atomic Force Microscopy, we found that optimal JGB concentrations enhance the morphology and roughness of the copper foil roughening layer while maintaining high peel strength. The ideal concentration of 3 mg/L achieved an average roughness of 0.953 µm and a peel strength of 0.946 N/mm. JGB's effectiveness in inhibiting copper deposition was confirmed through cyclic voltammetry, linear sweep voltammetry, and electrochemical impedance spectroscopy. Density Functional Theory calculations and in situ infrared spectroscopy elucidated JGB's adsorption and coordination actions, which have a synergistic effect on its inhibitory performance. Further investigations with molecular dynamics simulations and finite element analysis demonstrated JGB's preferential adsorption in areas of high electric field intensity, effectively controlling the copper grain morphology in the roughening layer. This research highlights the potential of dye-type additives in improving copper foil roughening for printed circuit boards applications. Future research should explore the long-term stability and environmental impact of JGB in industrial applications, while investigating other dye-type additives may further optimize the roughening process to meet diverse printed circuit boards manufacturing needs.

Numerical Simulation of Improving the Efficienty of Photovoltaic Thermal Panels

Abstract The need to optimize the operation of photovoltaic modules inevitably arises with the development of green energy production technology. In order to achieve a good technological yield, durability and efficiency in production, continuous studies and innovations are required. This study focuses on simulating the operation of water-cooled and uncooled PV modules in order to understand the temperature-dependent PV operation. This cooling module consists, in the first phase, of a copper coil through which water circulates, and in the second phase, of a coolant distributor/collector system. The module is attached to the lower surface of the photovoltaic panel, respectively to the teller foil layer. For this simulation we used the Ansys software package (Discovery, Fluent and Space Claim).

Thermal insulation box design for maintaining cool temperature and the postharvest quality of okra

Postharvest loss of okra is caused by its high respiration rate and temperature fluctuations in the supply chain. To address this, five thermal insulation boxes were designed, combining different materials, and evaluated for okra quality during simulated transportation and storage. The treatments included the standard foam box, metalized foam sheet (two layers consisting of aluminum foil and expanded polyethylene), prototype-A (three layers consisting of dual layer of aluminum foil and expanded polyethylene), prototype-B (four layers consisting of aluminum foil, nonwoven, expanded polyethylene, and aluminum foil), and standard regular slotted container. Material tests revealed that aluminum foil and expanded polyethylene had the lowest thermal heat energy. The composite sandwich box design, prototype-A, demonstrated the highest maximum insulation time of 28 h and thermal resistance of 0.332 m2°C/W. Prototype-A and prototype-B effectively maintained low temperature fluctuation, minimized air and okra temperature changes, and maintained 6.19 to 8.25 % CO2, which was within an acceptable range of 4–10 % for okra. Both prototypes exhibited reduced percentage mass loss in okra below 5 %. Importantly, both prototypes demonstrated the lowest incidence of okra pod surface browning and maintained the quality for 6 d, surpassing metalized foam sheet and standard regular slotted container. These findings offer sandwich design with 3 or 4 layers as promising alternatives for thermal insulation boxes in cold chain management, enhancing the transport packaging of okra under ambient environments compared to the standard foam box.

Reliability of micro-resistance welded dissimilar connection between Ag-plated Kovar foil and GaAs space solar cell: Processing, microstructure and bonding strength

Solar panels in low earth orbit (LEO) can suffer from damage caused by atomic oxygen (AO) exposure and thermal shock, which may shorten the service life of their interconnectors and joints. Ag-plated Kovar foil has emerged as a promising material for interconnecting solar cell arrays. This study uses parallel gap resistance welding (PGRW) to conduct ultrafast Ag-plated Kovar foil and solar cell bonding in just 190 ms. The bonding strength depends on the current densities, with a diffused interface observed at a density of 475 A/mm2. The EBSD results show that grains of Ag layer and Au layer grow at the central bonding interface, whereas grains of Ag layer and Au layer form a weakened bonded line at the edge bonding interface. The thermal reliability of joints with Ag-plated Kovar foil is better than traditional Ag foil, with no decline in tensile-shear force observed even after multiple thermal cycles. Although the Ag layer of Kovar foil oxidizes as AgO and Ag2O in an AO environment, the joining interface remains unaffected. This investigation into PGRW joints of Ag-plated Kovar foil is critical for enhancing the high reliability of solar arrays in harsh temperatures and AO space environments.

Multi-layer solid-state ultrasonic additive manufacturing of aluminum/copper: local properties and texture

Ultrasonic additive manufacturing (UAM) is an advanced joining technique that utilizes ultrasonic vibrations to bond layers of metal foil together. UAM offers several benefits over traditional manufacturing methods, including enhanced design flexibility and reduced material waste, and its potential applications in various industries such as aerospace, automotive, and biomedical engineering are being actively explored. The study employs a nanoindentation apparatus to investigate the effect of the UAM process on the local mechanical properties of the bonded interface, along with changes in microstructure, which were investigated using scanning electron microscopy and electron back-scattered diffraction. The results revealed a significant correlation between material hardness and local plasticity. EBSD has revealed that the grain size distribution of Al far from the interface contains 57% of the grains less than 3 µm in size, while at the interface this number rises to approximately 78%, indicating that the average grain size decreases as it approaches the interface. This result is consistent with nanoindentation results that demonstrated a gradual change in the hardness of Al foil far from the interface to close to the interface (the maximum penetration depth near the interface was 500 nm less than far from the interface). Both EBSD and nanoindentation disclose the effect of work hardening close to the interface, which is related to dislocation accumulation with a density of 8.6×10-10cm-2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$8.6\ imes {10}^{-10} {{\ ext{cm}}}^{-2}$$\\end{document} beneath the interface. The consistency of hardness and Young’s modulus with the pole figures and microscopic images demonstrated that plasticity flow and fine grain distribution would only occur in the vicinity of the interface in the softer metal region. Although the harder metal did not exhibit plasticity or recrystallization, the hardness, and Young’s modulus map indicated the formation of a layer of small grains close to the interface on the aluminum side owing to strain hardening and dynamic recrystallization.

DESIGN OF RICE HUSK ROTARY DRYER USING WASTE HEAT ELECTROSTATIC PRECIPITATOR OF THE CEMENT INDUSTRY

ESP or electrostatic precipitator is a device used to capture particulate matter, such as dust, in exhaust gases using electrostatic principles. In the cement industry, ESP is commonly placed after the clinker cooler to clean the exhaust air from the cooling process, ensuring it is free from clinker dust. The clinker cooler is a device that cools down the clinker using air, reducing its temperature from an initial temperature of around 1450°C to approximately 100°C - 120°C. The exhaust air from the clinker cooler is then passed through the ESP at temperatures ranging from around 237°C to 311°C. Based on the temperature data, the exhaust air from the ESP has the potential for heat reuse for other processes, including as a heat source for drying rice husk, which is a common alternative fuel used in the cement industry and typically has a moisture content of around 25%-37%. The results of this design indicate that the exhaust heat from the ESP, with an input temperature of 275°C, is capable of drying rice straw pellets from a moisture content of 25% to 14.73% using a designed rotary dryer with a capacity of 21.6 t/h, a length of 41.58 m, and a diameter of 2.92 m. It is constructed using ASTM 283 C material with a thickness of 8.76 mm and is insulated with a 15.6 mm thick layer of aluminum foil.

Proton Beam Range and Charge Verification Using Multilayer Faraday Collector.

A daily quality assurance (QA) check in proton therapy is ensuring that the range of each proton beam energy in water is accurate to 1 mm. This is important for ensuring that the tumor is adequately irradiated while minimizing damage to surrounding healthy tissue. It is also important to verify the total charge collected against the beam model. This work proposes a time-efficient method for verifying the range and total charge of proton beams at different energies using a multilayer Faraday collector (MLFC). We used an MLFC-128-250 MeV comprising 128 layers of thin copper foils separated by thin insulating KaptonTM layers. Protons passing through the collector induce a charge on the metallic foils, which is integrated and measured by a multichannel electrometer. The charge deposition on the foils provides information about the beam range. Our results show that the proton beam range obtained using MLFC correlates closely with the range obtained from commissioning water tank measurements for all proton energies. Upon applying a range calibration factor, the maximum deviation is 0.4 g/cm2. The MLFC range showed no dependence on the number of monitor units and the source-to-surface distance. Range measurements collected over multiple weeks exhibited stability. The total charge collected agrees closely with the theoretical charge from the treatment planning system beam model for low- and mid-range energies. We have calibrated and commissioned the use of the MLFC to easily verify range and total charge of proton beams. This tool will improve the workflow efficiency of the proton QA.

Photopolymer-metal Composites Based on Metal Foil Deposition on Additive Manufactured Substrates: An Overview

Photopolymer materials are a type of polymer material that can undergo chemical reactions when exposed to light of a specific wavelength or intensity. Liquid photopolymers are used in applications such as 3D printing, where they are deposited layer by layer and cured by exposure to light. Solid photopolymers, also known as photoresists, are used in applications such as lithography and microfabrication, where they are applied as a thin film and selectively exposed to light to create a pattern. The properties of photopolymer materials, such as mechanical strength, thermal stability, and chemical resistance, can be tailored by adjusting the monomer type, photo initiator type, and processing parameters such as the exposure time and intensity. Overall, photopolymer materials are a versatile and widely used type of polymer material that can be tailored for specific applications through the choice of monomer, photo initiator, and processing parameters. Photopolymer-metal composites based on metal foil deposition on additive manufactured substrates are a technique for creating composite materials with a combination of metal and polymer properties. This approach involves the deposition of a thin layer of metal foil onto a 3D printed polymer substrate, which is then cured using photopolymerization to create a composite material with unique properties.

Anisotropic Piezoresistive Sensors Made with Magnetically Induced Vertically Aligned Carbon Nanotubes/Polydimethylsiloxane.

A piezoresistive material consisting of internal vertically aligned carbon nanotubes acting in concert with an external microdome structure is prepared to obtain a flexible piezoresistive sensor with high anisotropy. Here, we first obtained flexible piezoresistive composites (VCP) with anisotropic properties by inducing the vertical alignment of multiwalled carbon nanotubes in the pressure direction under a weak magnetic field of 0.6 T. Then, the composite with a microdome structure on the surface (m-VCP) was fabricated by a mold with a microstructure to further increase the anisotropy of the composite. The m-VCP microstructure was docked with VCP and placed between two layers of copper foil. With the synergistic effect of vertically aligned carbon nanotubes and the microdome structure, the sensitivity of the flexible sensor in the pressure direction was dramatically increased. In the low-strain range (0-6%), the sensitivity of m-VCP (GF = 9.208) is improved by 49% compared to m-CP and by 86% compared to VCP. The sensor has high anisotropy in the piezoresistive direction and retains good fatigue resistance under fatigue testing for 2000 cycles. This means that the sensor can be used in emerging fields such as human health monitoring, wearable electronics, and intelligent human-computer interaction.

Modeling and characteristic investigation of practical gas dynamic bearings with stacked perforated foils

this paper presents a stacked perforated foil bearing to address plastic deformation and complex processes of traditional gas foil bearing, which consists of a top foil, three stacked perforated foils and a bearing sleeve. Three layers of perforated foils are stacked to form a stacked perforated foils as the elastic structure of the SPFB, providing sufficient structural deformation and multi-point friction. The theoretical model of the SPFB, which couples a structural model based on a single supported beam with Reynolds equation, is solved using FDM, and the predicted results are validated against experimental results. The static and dynamic characteristics of the SPFB are analyzed under multiple structural and operational parameters, which improves the theoretical basis for commercial application.

Layered metamaterials with Sierpinski triangular fractal metasurface: Compatible stealth for S-band radar and infrared

Due to the completely opposite stealth mechanisms of radar and infrared waves, and the limitation of the Planck–Rozanov limit, compatible stealth of S-band radar and infrared is extremely difficult to realize at thin thicknesses. In order to solve the problem, a layered metamaterial consisting of infrared stealth layer (IRSL) with aluminum foil and radar stealth layer (RASL) with carbonyl iron powder is designed. The excellent infrared stealth performance (infrared emissivity < 0.3) is achieved because of the low infrared emissivity aluminum foil and reasonable area design. Meanwhile, the Sierpinski triangular fractal structure of IRSL not only serves to reduce the reflection of radar waves, but also introduces the electromagnetic double resonance mechanism of one-dimensional electric resonance and two-dimensional magnetic resonance to lose waves. Therefore, the effective absorption (RL < −10 dB) of 2.12–3.5 GHz in S-band is achieved with a thickness of only 2.24 mm. The double-layer model with fractal structure in this work realizes the perfect compatible stealth for S-band radar and infrared at extremely thin thickness, which provides a new design idea for the development of multi-band compatible stealth.

Artistic Thinking in Scientific Research

Doctoral programs in the fine arts, instead of coming up with their own ways of doing things, tend to adopt standards from the humanities, which themselves tend to adopt standards from science. Because of being preoccupied with trying to look like other disciplines, artistic thinking within artistic doctorates gets suppressed. But if we look into science directly and not through this second-hand approach, we can find aspects of scientific thinking that are closer to art than to the humanities.&#x0D; In this paper, I give examples of artistic thinking in the work of various scientists and mathematicians: a non-fiction book that uses fiction (Douglas Hofstadter’s book Gödel, Escher, Bach), a linguistic analysis that concludes with a story (Livia Polanyi’s book Telling the American Story), scientific lectures with unusual formal aspects (Roger Penrose’s “VJing” of multiple layers of foils through an overhead projector, David Deutsch’s Lectures on Quantum Computation), and a collective hiding behind a fictional mathematician (Nicolas Bourbaki). I also briefly introduce the problem of verbal overshadowing and the effects it may have on the creative process in art.

Reaction-passivation mechanism driven materials separation for recycling of spent lithium-ion batteries

Development of effective recycling strategies for cathode materials in spent lithium-ion batteries are highly desirable but remain significant challenges, among which facile separation of Al foil and active material layer of cathode makes up the first important step. Here, we propose a reaction-passivation driven mechanism for facile separation of Al foil and active material layer. Experimentally, >99.9% separation efficiency for Al foil and LiNi0.55Co0.15Mn0.3O2 layer is realized for a 102 Ah spent cell within 5 mins, and ultrathin, dense aluminum-phytic acid complex layer is in-situ formed on Al foil immediately after its contact with phytic acid, which suppresses continuous Al corrosion. Besides, the dissolution of transitional metal from LiNi0.55Co0.15Mn0.3O2 is negligible and good structural integrity of LiNi0.55Co0.15Mn0.3O2 is well-maintained during the processing. This work demonstrates a feasible approach for Al foil-active material layer separation of cathode and can promote the green and energy-saving battery recycling towards practical applications.

Mechanical characterization and modeling of microstructural deformation of Si anode sheet

Battery anodes generally have a layered structure consisting of an active material layer (including binder, conductive carbon, and active material) and a foil layer of the current collector (copper foil). Such layered structures bring grand challenges to our understanding of the mechanical behaviors of the Si-based anode sheets since the large deformation of the Si particles, and solid-solid interfacial interactions (particle-particle and particle-binder) are key knowledge in high-energy, safe, and durable batteries. Herein, we characterize a typical commercialized Si-based anode with detailed microstructure morphology. Representative mechanical tests, including tensile and compression tests, are conducted to characterize the constitutive behaviors of the anode materials. Further, we propose a 3D computational model with detailed descriptions of the microstructures of the active material is established to enable a fundamental understanding of the deformation behaviors. Results present a comprehensive understanding of the Si-based anode materials for the first time and provide a powerful model for the future design of the anode for the next-generation batteries.