Thin Aluminum Foil Research Articles

Rapid identification of the coefficient of moisture expansion of polymer materials by the employment of plates with asymmetric concentration fields

The paper pursues the development of a novel methodology for the rapid identification of the diffuso-mechanical properties of polymer materials based on the employment of plates subject to asymmetric moisture concentration fields. The study is carried out on epoxy plate samples equipped with a thin aluminium foil on a surface exposed to the environment to promote asymmetric moisture absorption. The asymmetric moisture fields promote deformations of the plate. Mass gain and plate curvatures are measured as a function of time during conditioning. By using a weakly coupled diffuso-mechanical model: 1D Fick’s diffusion model and 2D plane stress hygroelastic model the diffuso-mechanical properties of the material can be then identified. Due to the chosen size of the experimental samples the present study allows the identification of the coefficient of moisture expansion of the epoxy material. For the material under study, the following values can be identified for saturation mass gain, water diffusivity and coefficient of moisture expansion respectively: 1.67%, 0.025 mm2.h−1, 0.1628.

Design and thermal test of high-vacuum insulator for heat delivery pipes

Thermal piping insulation of implants is crucial for heat delivery, production, collection, or storage at high temperature values. It is currently obtained by enveloping low thermal conductivity materials such as rockwool, fiberglass, polyurethane, polystyrene, and aerogel. However, better performances can be reached by adopting vacuum technology. In this case, conductive losses are annihilated, and the radiative heat transfer mechanism represents the only loss mechanism. Here, we compare a high vacuum-based novel solution and the traditional insulation for heat delivery applications. We propose a high vacuum- based solution consisting of an evacuated gap that surrounds the hot pipe coated by a thin aluminium foil. Experimental results using this novel solution show a fivefold reduction of the thermal radiation losses compared to the traditional solutions when in the temperature range between 100 °C and 250 °C.

Unveiling Hidden Prints: Optically stimulated luminescence for latent fingerprint detection

Fluorescent lighting and optical techniques have been widely utilized to enhance the detection of latent fingerprints. However, the development of new techniques is imperative to expand the range of surfaces from which latent fingerprints can be detected. When relying on traditional methods, fingerprint evidence can remain undetected or even disregarded due to insufficient detection and limited detail, especially when dealing with a luminescent background.In this study, we propose the utilization of optically stimulated luminescence (OSL) applied to a Ba2SiO4 matrix, co-doped with Eu2+ and Dy3+, as a powerful method for visualizing latent fingerprints on various surfaces, including thin plastic bags, rigid duct tape, thin aluminum foil, and glass slices. This technique effectively eliminates any luminescent background and significantly enhances optical imaging.This represents the first successful application of OSL in the development of latent fingerprints, thus paving the way for more efficient and effective forensic techniques in the future.

Underwater microsecond timescale electrical explosions of aluminum and copper foils

We present results on underwater electrical explosions of thin aluminum and copper foils using a generator delivering ∼200 kA current amplitude, ∼0.9 μs rise time pulses. Time-resolved shadow imaging displays the generation of a strong planar shock wave in water in the vicinity of the exploding foil. Using time-resolved spectroscopy, aluminum oxide (AlO) absorption bands were observed in a Planckian-like spectrum, indicating that aluminum combustion starts when aluminum vaporizes. It is also shown that the strongest shock wave is obtained for the largest linear energy deposition rate to the foil.

Investigations on laser beam welding of thin aluminum foils with additional filler wire

Nowadays, battery-electric drives and energy storage are elected to be the future technologies. In the manufacturing of parts for electric applications, laser beam welding is an appropriate and favorable welding method. The characteristics of high welding speed, local heat input, and the contact-free process allow efficient and automatable processes. For electrodes, mainly copper and aluminum are used. Many foils with thicknesses of an area of 10 μm have to be connected to create battery cells. Different than expected, aluminum is a more challenging material to produce than others. Pore formation is also extended in aluminum due to the presence of air between the foils. The connecting cross section is thereby reduced. Furthermore, there is detachment in the fusion area and a high weld seam undercut. In addition to insufficient clamping, a lack of material reduces strength and, thus, usability. In the research presented here, the use of aluminum filler wire (AA 1050A) and shielding gas are investigated for the application of welding 40 aluminum foils (AA 1050A) with a thickness of 15 μm to an aluminum sheet with a thickness of 2 mm using infrared laser beam wavelength. The aims of the process development are welds with high connection widths and high quality as well as reproducibility to provide excellent mechanical properties and the highest electrical conductivity.

Bulk material influence on the aggressiveness of cavitation – Questioning the microjet impact influence and suggesting a possible way to erosion mitigation

In a study conducted over 10 years ago (Petkovsek and Dular, 2013) [1] we noticed that the thin metal sheet sustains less cavitation damage when it is attached to an acrylic glass (PMMA) than in the case when we attached it to quartz glass (SiO2). The reason for this was not explored at the time.In the present paper we present a systematic study of single cavitation bubble erosion of a thin aluminum foil, which was attached to either PMMA or SiO2 plate. We show that the damage sustained on the foil attached to PMMA plate is significantly smaller regardless of the bubble collapse distance from the boundary. The result is surprising since one would expect the weak foil to be severely damaged regardless of the material it is attached to.By femtosecond illumination and high-speed image acquisition we were able to capture the formation and progression of the shock waves, which are emitted at cavitation bubble collapse and observed that they are reflected on SiO2 boundary but that they traverse the PMMA bulk material. We offer an explanation that to achieve less damage the bulk material needs to have acoustic impedance similar to the one of the liquid medium in which cavitation occurs.Further on, we constructed a simple composite material where PMMA was attached to the SiO2 and showed that we can partially mitigate the damage. This was further confirmed by ultrasonic cavitation erosion tests.The results also imply that the cavitation damage originates solely from the shock wave, which is emitted at cavitation bubble collapse – consequently putting the idea of microjet impact mechanism under question. Finally, the study offers a new exciting approach to mitigate cavitation erosion by fine tuning the acoustic impedance of the coatings.

Electrodeposition of Al foil for the collector of lithium-ion batteries by electrorefining in [Emim]Cl-AlCl3 ionic liquid with O2− ion at room temperature: Electrochemical dissolution behavior of Al anode

The continuous electrochemical dissolution of anode is significant to electrorefining in ionic liquid at room temperature. The electrochemically dissolved behavior of an aluminum anode was investigated in [Emim]Cl-AlCl3 ionic liquid with O2− ion by cyclic voltammetric method, constant potential dissolution, and SEM, EDS. It found that the dissolved process of the aluminum anode and electrodeposition of insulated darkness Al–O–Cl species exist together at a relatively low potential. Moreover, the Al–O–Cl species prevent the continuous dissolution of the aluminum anode. However, it can be electrochemically dissolved at a high potential that is beyond the anodic passivation potential, assuring continuous dissolution of the aluminum anode. Moreover, holding a constant anodic potential of 3.0 V for 30 min, we electrodeposited the dense and thin aluminum foil of 2.5 µm with a rough surface. The positive electrode of lithium-ion batteries using it as the collector shows superior properties.

Delta Electron Emission Yield of Relativistic Electron Passing Through Thin Aluminum Foils

The results of the experimental research of the δ-electrons yield from the thin aluminum foil are presented. The thickness range of the aluminum foils is \(8 \ldots 100\) µm. The energy of primary electrons varies from 2.5 to 30 MeV. The values of the average cross section for δ-electron production (generation and emission) from aluminum were obtained. It has been established that for 8 µm Al foil it is about \(8.17 \cdot 10^{ - 23}\) cm2. Finally, comparisons of the obtained results with the calculated ones are discussed.

A Two-Dimensional Non-Destructive Beam Monitoring Detector for Ion Beams

A two-dimensional beam monitoring detector named π2 has been developed and tested at the Bern University Hospital, using an 18 MeV proton beam provided by a medical cyclotron. This non-destructive device utilises a scintillating compound (P47 phosphor) coated onto a thin aluminium foil that is angled at 45∘ with respect to the beam axis. The scintillating light produced when the beam passes through the foil is captured by a CMOS camera, resulting in a two-dimensional image of the beam profile. Custom software is then used to analyse the image and extract valuable information about the beam’s position, shape, and intensity. The focus of the experimental work was on characterising the performance of the π2 with the 18 MeV proton beam. The linearity of the detector’s output signal was evaluated for proton fluxes ranging from 2·1010cm−2·s−1 to 5·1011cm−2·s−1. Furthermore, the beam profiles measured with the π2 were found to be consistent with reference measurements obtained using alternative beam monitors. Additionally, the experiments also involved studying the beam scattering caused by the foil and scintillating layer. Finally, in a long-term radiation test, the detector demonstrated a stable response up to an integrated proton flux of 3·1015cm−2. The π2 is currently being used at the Bern cyclotron for monitoring beams in the development of new methods for medical radioisotope production and for radiation hardness studies. The π2 has potential applications in several fields that involve the use of accelerated ions, such as cancer particle therapy, medical radioisotope production and radiation hardness studies.

Enhancement of heat transfer from solar thermal collector using nanofluid

Abstract Global energy consumption is increasing due to population growth and with it the adverse impact of fossil fuels on the environment, making it necessary to use renewable energy sources and convert them to electrical energy using different technologies. However, the solar energy potential remains unused, while it has numerous advantages, including as a source of clean electricity and heat. One of the main difficulties in energy-saving and compacted design is how to increase the heat transfer of solar equipment. As an innovative approach to enhancing fluids’ heat transfer performance, some of the most active techniques are to exchange the working fluid with nanofluids. This work attempted to demonstrate heat transfer behavior changes when using nickel oxide (NiO), aluminum oxide (Al2O3), and copper oxide (CuO) as nanofluids at concentration volumes of 0.05, 0.075, and 0.1%. For this goal, a conical solar collector was built using local public steel sheets. Insulating polyurethane foam padding is used inside the cone. The sun’s energy is focused on the absorbing surface using thin reflective aluminum foil. The study also includes a literature review showing how nanofluids can improve heat transfer in solar collectors. The results showed that adding nanoparticles can increase the rate of heat transfer and CuO nanofluids have better augmentation in heat transfer than Al2O3 or NiO-water nanofluids where 1% CuO nanofluids increases the efficiency by up to 7% compared to water.

Zero-ventilated self-cooled induction heating device: Topology and component engineering

• Self-cooled power electronics controller in a thermally constrained zero-ventilated enclosure. • Power loss reduction and better loss distribution through component engineering. • Power loss reduction and its superior distribution through choice of topology. • Heat removal by internal convection based on buoyant force inside. • Product validation of a 1.5 kW, 50 kHz zero-ventilated power controller. Due to its non-contact mode of power transfer, the induction heating principle is favorably used in the packaging industry for sealing of wide range plastic and glass containers. In cap sealing, the power transferred to thin aluminum foil is used to create a bond between the foil and the lip of the bottle. The process ambiance for sealing bottles containing different types of products could be different. Dust prone environment prevailing for sealing coffee, nutraceuticals, several pharma products, etc. recommends the use of an air-tight enclosure. Likewise, to avoid water particles entering the enclosure during its frequent cleaning of exterior surfaces, packaging solutions for the dairy industry need water-tight enclosures. The process ambiance and nature of products are such that those power controllers would increasingly be housed in IP 65 enclosures. The air movement inside i.e., the free convection is restricted. To make the controller inherently self-cooled, this research proposes to make the internal convection effective by creating requisite buoyant force through proper choice of power converter topology where component engineering would also play important role. This article details that the choice of topology should not only reduce the power loss, it would also be useful for loss distribution. It further details that the choice of components is critical to ensure effective internal air movement for reliable operation of the controller. The proposed idea has been validated by designing a 1.5 kW, 47 kHz power controller housed in a zero ventilated enclosure that also includes the coil head.

Investigations on laser beam welding of thin foils of copper and aluminum regarding weld seam quality using different laser beam sources

Nowadays, there is a strong and growing ambition to switch from combustion technology to battery-electric drives, and energy storage is spotlighted. Laser beam welding is an appropriate and favorable welding technology in battery production. Due to the high welding speed, the local heat input, the contact freeness efficient, and automatable processes can be established. Materials used in batteries for electrodes that have to be connected are commonly copper and aluminum. Specifically, copper is highly reflective for widely used infrared laser beam wavelengths. Furthermore, the thickness in the area of 10 μm is quite challenging to deal with, in terms of gap free clamping and avoidance of damage to the material as well as distortion during welding. There is a fine line regarding energy input between burning the material and generating a lack of fusion. In the presented research, welding approaches with different laser beam sources emitting laser beams with infrared wavelengths, various beam shapes, and welding modes (continuous and pulsed) are studied. A total of 40 copper foils with a thickness of 10 μm and 40 aluminum foils with a thickness of 15 μm are welded to similar sheet metals. Aim of the process development are welds with high quality and high connection widths to provide the best electric conductivity.

A novel combined anodic-adhesive bonding technique for joining glass to metal for micro device applications

In this study, a novel bonding technique consisting of anodic and adhesive bonding methods was proposed for joining glass to metal. The Pyrex glass substrate was metallized with a thin aluminum foil using anodic bonding and then it was bonded to a thick aluminum substrate by adhesive bonding using an epoxy adhesive. The effect of metallization and different surface treatments was examined on the bonding surface characteristics and joint strength by measuring the surface morphology, roughness and contact angle and mechanical testing single lap joints. The results showed that metallizing and abrading glass surfaces both improved the bonding surface wettability and joint strength. Abrading the glass bonding surface of the glass-aluminum joint caused the joint strength to improve by 20%, while metallizing and abrading glass bonding surface resulted in a synergistic effect on the joint strength with a 75% improvement. Furthermore, the failure mode of the joints was considerably influenced by the surface metallization and treatment methods.

The Role of Interfacial Adhesion on the Mechanical Behavior of Thin Metal/Polymer Laminate with Surface Roughness.

Metal/polymer laminate has versatile applications in industry due to the essential roles of its constituents in controlling its mechanical behavior. Therefore, efforts to enhance a laminate’s performance should target its mechanical behavior. One of the most influencing features of the mechanical behavior of this type of thin laminate is the interface layer properties. This study concentrates on the mechanical response of thin aluminum (Al) foil deposited on a polymer substrate by calibrating its interfacial layer properties based on available uniaxial tensile tests performed on thin Al/polymer laminate. Then, taking into account the calibrated parameters for the interface layer, which leads to mimicking the real conditions of the laminate, one type of imperfection is introduced as a wavy roughness on the surface of each layer with different amplitudes to investigate its influence on the overall mechanical behavior of the laminate and its failure mode. The results highlighted that the existence of the roughness on the surface of the polymer layer reduces the maximum engineering stress of the laminate more severely compared to other conditions. As the roughness amplitude increases, the maximum stress reduces a lot. The distribution of equivalent plastic strains represents the appearance of the shear bands in the Al layer and an almost uniform distribution for the polymer layer. In the case of existing roughness on each layer, a higher amount of plastic strain accumulation occurs in the middle of the polymer layer and top corners of the thin Al layer. Due to the significant effect of interfacial layer properties to improve the maximum strength of the laminate and its final elongation, a parametric study is performed, taking into account different interfacial properties. The results indicate that laminate behavior with weaker separation properties in the interface layer is mostly unaffected by adopting higher tractions, and no change happens in the case of high separation considering weak tractions.

Determination of the radon diffusion coefficient of thin polyethene and aluminium foils used as single or multilayer configuration barriers

Radon is a radioactive noble gas exhaled from the soil that can reach high concentrations in enclosed spaces. As elevated concentrations cause serious health problems, legislation has been put in place in many countries to regulate the limit concentration and even establish mitigation techniques. One of the most effective techniques for new buildings is the installation of radon barriers. The most important parameter determining whether the barrier is adequate to protect against radon is the diffusion coefficient, whose measurement methodology is standardized in ISO/TS 11665–13:2017. This work applies a previously tested modification of this standard to calculate the radon diffusion coefficient of different materials used as single or multilayer form barriers. Given that there are wasted laminated materials, composed of polymeric materials and aluminium, which are difficult to recycle, a preliminary study of the possible effectiveness of these materials as radon barriers will be carried out using these materials separately or in combination. The materials to be tested are 10-μm sheets of polyethene (PE) and 15-μm sheets of aluminium (Al), testing in each case one, two and three layers of each material. In addition, combinations of the two materials, i.e., PE-Al-PE and PE-Al-PE-Al-PE, are also studied. The diffusion coefficients obtained vary around 2·10−12 m2/s for PE and around 1·10−13 m2/s in the case of Al. The combination of both materials improved results obtained for single-materials barriers giving a diffusion coefficient between 10−13 and 10−14 m2/s. Radon reductions achieved range from 70 to 87.5% for PE to more than 98% for Al and the materials combinations. The excellent radon shielding capacity of aluminium is observed, which grows with increasing material thickness. Furthermore, it can be stated that the use of multilayer materials of different nature is very effective in reducing the radon concentration reaching an enclosed space and the use of aluminium in some of the layers is essential to achieve a more significant shielding effect.

Diffusional behavior of nanoscale lead inclusions in crystalline aluminum

Abstract In-situ transmission electron microscopy (TEM) observations reveal a permanent chaotic motion of nanosized liquid Pb inclusions embedded in thin aluminum foils. Individual trajectories of the inclusions were analysed to determine the character of their motion. The inclusions moving freely inside a crystal display motion with three-dimensional random walk characteristics while inclusions attached to dislocations display spatially confined random motion localized to the close vicinity of the dislocation lines. The diffusion coefficients of inclusions moving freely in the matrix were determined using Einstein’s classical equation for diffusion of Brownian particles. The diffusion coefficients of inclusions trapped on dislocations were found using an equation based on Smoluchowski’s analysis of Brownian motion of a particle under the action of a linear elastic restoring force. The dependence of the diffusivity on the size of the inclusions suggests that their mobility is controlled by kinetic processes on the inclusion/matrix interfaces. The Arrhenius analysis exhibits two regions with different temperature dependencies. We suppose that this is related to the existence of {111} facets on the inclusion/matrix interfaces.

Experimental Study of the Behavior of Phase Change Materials during Interrupted Phase Change Processes

This research article explores the behavior of a phase change material (PCM) when it undergoes interrupted melting and freezing, through experimental investigations using a heat flow meter apparatus. A fatty acid-based organic PCM, encapsulated within polyethylene and thin aluminum foil layers, was experimentally tested in this study. Experiments were designed to represent multiple interrupted phase change scenarios that could occur within PCMs applied in buildings. The experimental results were analyzed and compared with previously reported assumptions in numerical models dealing with PCM hysteresis and interrupted phase change processes. These comparisons indicated that the assumptions used in the different numerical models considered can capture the interrupted phase change phenomena with varying degrees of accuracy. The findings also highlighted the need for additional experimental research on different phase change processes that can occur in building applications of PCMs.

Study of SXR/EUV radiation of exploded foils and wires with spectral, spatial and temporal resolution simultaneously on KING electric discharge facility

The results of studies of the soft x-ray and extreme ultraviolet (SXR/EUV) radiation of thin flat aluminum foils and wires under the explosion in an electric discharge on the compact high-current KING generator are presented. These studies were based on the SXR/EUV spectroscopy with a spectral resolution of 6 Å, a temporal resolution of 5 ns and a spatial resolution of 200 μm. To study the plasma radiation of exploded foils and wires in the SXR/EUV range, we used a transmission diffraction grating spectrograph which in combination with two additional slits provided spectral and spatial resolution. The spectrograph was coupled with a four-frame recorder based on a microchannel plate for providing temporal resolution. The analysis and comparison of the spectral, spatial, temporal, and energy characteristics of the SXR/EUV radiation of plasma formed under the explosion of foils and wires of a similar mass made of aluminum was carried out. The spectra were calculated as well and the plasma parameters and their changes in time and space were estimated on the basis of these calculations and comparison with relevant experimental results. Experiments have shown that when foils explode, a single intense source of SXR/EUV radiation is formed with radiated energy in the range of 10–20 J and a power of up to 100 MW in the quantum energy range from 30 to 250 eV. At the same time, the radiation power under the explosion of foils turned out to be about twice above the power under the explosion of wires of comparable mass.

Additively manufactured electrodes for plasma and power-flow studies in high-power transmission lines on the 1-MA MAIZE facility.

Power-flow studies on the 30-MA, 100-ns Z facility at Sandia National Laboratories have shown that plasmas in the facility's magnetically insulated transmission lines (MITLs) and double post-hole convolute can result in a loss of current delivered to the load. To study power-flow physics on the 1-MA, 100-ns MAIZE facility at the University of Michigan, planar MITL loads and planar post-hole convolute loads have been developed that extend into the lines of sight for various imaging diagnostics on MAIZE. These loads use 3D-printed dielectric support structures lined with thin foils of either aluminum or stainless steel. The metal foils serve as the current-carrying power-flow surfaces, which generate plasma during the current pulse. The foil thickness (50 µm) and widths (11.5-16mm) are selected to ensure a sufficient linear current density (0.5-0.7 MA/cm) for plasma formation. Laser backlighting (532nm) and visible-light self-emission imaging capture the overall plasma evolution in the anode-cathode gaps, including the gap closure velocities (1-4 cm/μs).

A study on chemical cauterisation for small tympanic membrane perforation

To study the effectiveness of chemical cautery with patching on chronic tympanic membrane perforations of the pars tensa. Thirty-eight patients with dry tympanic membrane perforations due to inflammatory or traumatic etiology were selected after treating the primary etiological factors like septal deviation and allergic rhinitis. Fifty percentage silver nitrate was used to cauterize the margin and the perforation was covered with thin sterile aluminium foil as a patch. A maximum number of five applications were made, and the patients were followed up for the next 5 years. In this series of 38 patients, highest success was noted among those patients with traumatic perforation, while larger perforations were reduced to small pinhole sizes which were successfully closed by myringoplasty. An overall success rate of 73.75% was achieved. This is a time tested useful method which was popularized by Derlacki (1953), to close small to moderate sized tympanic membrane perforation and should be considered as a first line management in the treatment of tympanic membrane perforation prior to any surgical intervention. Apart from being a simple and economical mode of treatment, it is associated with minimal complications. Though various materials have been used to modify this technique, the principle remains the same and the results obtained in this study is comparable with the previous ones.