Layers Of Foil Research Articles

Recycling of Aseptic Beverage Cartons: A Review

Aseptic beverage cartons are multilayer polymer-coated paperboards with a layer of aluminum foil. Due to their multilayer structure it is commonly assumed that they cannot be recycled. This is not the case and this review details the multifarious processes that are used to recycle aseptic beverage cartons. Hydrapulping to recover the paper fibers that constitute 75% of the carton is the most widespread process, followed by the manufacture of construction materials such as boards and tiles which utilize the complete carton. A range of mechanical, chemical and thermal processes are used to separate the PolyAl (polyethylene and aluminum) residual that remains after the paper fibers have been recovered. The simplest process involves agglutination followed by extrusion to obtain pellets that can then be used in industrial and consumer products or combined with other materials such as lignocellulosic wastes. Chemical approaches involve the solubilization of polyethylene and the removal of aluminum. Various thermal processes have also been investigated and a novel microwave-induced pyrolysis process appears the most commercially viable. It is concluded that the focus in future years is likely to be on recycling cartons into construction materials where there is a theoretical yield of 100% compared with 75% for hydrapulping.

Micro-EDM-assisted machining micro-holes in printed circuit board

Printed circuit board (PCB) can provide assembly support and electrical connection for components in electronic systems. The machining of micro-holes in PCB is a necessary process and key step for its application in electronic components. Therefore, micro-holes are the key structures of PCB. At present, high-speed drilling based on micro-bit is the key supporting technology for machining PCB micro-holes. However, when the copper foil layer in PCB is machined by this technology, the micro-holes are prone to defects such as hole mouth burr and hole nail head, which could seriously affect the performance of PCB. Focusing on the above problems, this paper proposed to use micro electro-discharge machining (micro-EDM) for assisted machining of PCB micro-holes. With this method, the copper foil layer in PCB was machined by micro-EDM, so as to remove hole mouth burr and hole nail head. The paper detailedly studied the influence of micro-EDM voltage, pulse width and pulse interval on hole mouth burr and hole nail head. Finally, under the effects of 10,000 rpm rotational speed, 40 V voltage, 80 ns pulse width and 160 ns pulse interval, the micro-bit with diameter of 200 μm was used to carry out micro-EDM-assisted machining of the copper foil in PCB. From the machining results, it can be found that the hole mouth burr and the hole nail head were basically eliminated and PCB micro-holes with good quality were obtained by the proposed method.

Experimental Research on Foil Vibrations in a Gas Foil Bearing Carried Out Using an Ultra-High-Speed Camera

The foil bearing consists of parts made of very thin, properly shaped foils. Usually, it is very difficult or even impossible to measure the vibrations of these elements during the bearing operation using traditional sensors. Therefore, the authors of this article have proposed an entirely new approach to this issue. This article discusses the analysis of vibrations of the structural supporting layer of a gas foil bearing at high rotational speeds. Instead of using a traditional method to measure the bearing journal movement, the measurement was performed using an ultra-high-speed digital camera. This type of measurement was used for the first time to analyse foil bearing displacement. It turned out that doing so can give a far more vibrant picture of what is happening in gas foil bearings during their operation. The article includes an analysis of foil vibrations. This phenomenon has already been analysed numerically, and this is the first time it has been analysed experimentally. The registered motion of the foils can be compared with the results obtained from numerical models, thus allowing their further development. One such comparison is shown in this article.

Potential-induced sonoelectrochemical graphene nanosheets with vacancies as hydrogen peroxide reduction catalysts and sensors

Defective graphene nanosheets (dGN4V) with 5-9, 5-8-5, and point defects were synthesised by a sonoelectrochemical method, where a potential of 4 V (vs. Ag/AgCl) was applied to drive the rapid intercalation of phosphate ions between the layers of the graphite foil as a working electrode. In addition to these vacancies, double vacancy defects were also created when the applied potential was increased to 8 V (dGN8V). The defect density of dGN8V (2406 μm−2) was higher than that of dGN4V (1786 μm−2). Additionally, dGN8V and dGN4V were applied as catalysts for the hydrogen peroxide reduction reaction (HPRR). The mass activity of dGN8V (1.31 × 10−2 mA·μg−1) was greater than that of dGN4V (1.17 × 10−2 mA·μg−1) because of its high electrochemical surface area (ECSA, 1250.89 m2·g−1) and defect density (ND, 2406 μm−2), leading to low charge transfer resistance on the electrocatalytic interface. The ECSA and ND of dGN4V were 502.7 m2·g−1 and 1786 μm−2, respectively. Apart from its remarkable HPRR activity, the cost-effective dGN8V catalyst also showed potential as an amperometric sensor for the determination of H2O2.

Characterization of composite laminate with copper and AISI304 made by a diffusion bonding process

The composite laminate assembly was made by stacking alternate layers of AISI304 and copper foils. The copper and AISI304 foils of 0.1 mm thick were placed one above the other and during diffusion bonding experiments. The bonding parameter temperature was varied as 850, 900 and 925 ⁰C, constant pressure of 4 MPa, and bonding time of 60 min was maintained for all the experiments. The laminated joints were characterized by optical, scanning electron microscopy for grain size measurement and phase identification. Electron microprobe analysis (EPMA) was performed at the joint region for elemental analysis across the interface and into the base metals. At the AISI304 base metal side a maximum hardness of 342.6 VHN and at the copper base metal side, it was 152.5 VHN. For the sample bonded at 925 ⁰C, the shear strength was a maximum of 72.8 MPa. X-Ray Diffraction Analysis (XRD) revealed the presence of phases γ-Fe and γ-Cu, and intermetallic compounds such as FeCu 4 , Cu 2 CrNi, sigma (σ)-phase and oxide CuO.

Development of vibration damping materials based on butyl rubber: A study of the phase equilibrium, rheological, and dynamic properties of compositions

AbstractA detailed study of butyl rubber‐based vibration damping formulations linking their composition, morphology, phase structure, viscosity, mechanical loss factor, and other characteristics is presented for the first time. High performance of the compositions including aromatic petroleum oil is explained by limited solubility of the plasticizer that leads to the formation of a highly‐viscous emulsion (η20°C ≈ 1000 Pa·s) consisting of a swollen butyl rubber matrix and dispersed oil droplets in the broad composition range. Chalk is found to be the best inorganic filler as its spherical particles provide strong adhesion to the reinforcing layer of aluminum foil. Aiming to eliminate ecologically unfriendly aromatic compounds, a new low‐cost binding agent formulation based on butyl rubber mixed with polyisobutylene and highly refined mineral oil is suggested. Being environmentally safe, it possesses high viscosity of 1000–3000 Pa·s, cohesion strength of 3.5–5.0 N/cm, penetration of 4.5–6.0 mm, and mechanical loss factor up to 0.34 at room temperature, which are as good as, or even better than, the properties of currently produced vibration damping materials containing aromatic compounds. New materials can be used in car and aircraft parts for effective vibration isolation.

Intense proton acceleration in ultrarelativistic interaction with nanochannels

The authors compare thin layers of nanochannels and plain thin foils as targets for ultraintense laser driven proton acceleration, showing a more intense flux of protons with higher energy with nanochannels.

Elastic strain induced abnormal grain growth in graphene nanosheets (GNSs) reinforced copper (Cu) matrix composites

Orientation related grain growth stimuli during primary and secondary recrystallization of the metal matrix in laminated metal/non-metal composites demonstrate unique effect on orientation evolution but has rarely been investigated. In this work, the recrystallization and grain growth of Cu in a graphene nanosheets (GNSs) reinforced laminated Cu matrix composite during sintering was thoroughly investigated. The microstructure, texture and lattice strain evolution of the Cu/GNS composite was examined referenced to the Cu stack without GNSs by ex-situ and in-situ orientation characterization techniques (SEM-EBSD, neutron diffraction and synchrotron radiation) from mesoscale to macroscopic scale. The results evidenced that a strong Cube orientation was produced in the Cu/GNS composite instead of the individual non-Cube orientations in the pure Cu stack without GNSs. Detailed strain-state analysis of the Cu foils in the Cu/GNS composite revealed that the anisotropic expansion behavior of the GNS that is incompatible with that of the Cu foils imposed multiple elastic constraints to the foils during the sintering process, resulting in a biaxial isostrain state in the surface layers and a uniaxial compressive strain state in the central layer of each Cu foil. The elastic anisotropy of Cu favors the growth of the Cube oriented grains to minimize the total strain energy. This work clarified the thermal strain induced abnormal grain growth of selected orientations. The mechanism revealed can be useful for analysing abnormal grain growth in elastically strained materials and can also be applied to fabrication process for texturization or even monocrystallization.

Backwards extrapolation activation diagnostics and their dynamic range for pulsed neutron source measurements

Activation materials implanted within radiation detectors can be used to measure pulsed neutron fields. This work develops an instrument concept with the aim to maximise sensitivity to pulsed fusion neutron fields and, using a data-rejection algorithm combined with backwards extrapolation, enable neutron fluence estimates to be made over a large dynamic range. Through high-fidelity modelling of residual temporal emissions, and a parameterised approach, we study the sensitivity to neutrons of a plastic scintillator–Ag foil layer detector concept. For an optimal design we apply paralysable and non-paralysable deadtime models to the predicted response to D–D fusion neutron fields at various neutron field intensities. In high neutron fluence irradiation scenarios, where deadtime effects are strongly evident, we use our approach to make estimates of the fluence from instrument response data. We discuss the practical applications of such diagnostics used for plasma focus (PF) fusion experiments, such as at the PF-1000U facility in IPPLM, Poland, inertial confinement fusion and pulsed tokamak experiments, for example at MAST-U, where such diagnostics could complement fission counter-based neutron diagnostics in the future. Finally, we show that the calibration of such detection systems may be achieved using relatively low emission rate, steady state neutron sources, with calibration factors that are straightforward to apply to pulsed neutron field measurements.

Corrosion and puncture resistance of aluminium foil gas membranes beneath concrete slabs

Aluminium foil (AF) membranes are commonly installed below or above concrete floor slabs to reduce the migration of ground gases into buildings. The membranes typically comprise laminates of low-density polyethylene (LDPE), reinforcement and an aluminium foil layer. The key component providing gas resistance is the aluminium layer. This is typically 0.012 mm thick and is often encapsulated by very thin layers of LDPE. The foil is therefore vulnerable to damage from puncture by narrow sharp objects in the field. Aluminium corrodes in aggressive and moist environments and could therefore be affected by the fresh cement slabs and/or ground moisture. This paper summarises testing completed to assess the puncture and penetration vulnerability of AF membranes in real life scenarios and the observations from an experiment where AF membranes were exposed to various conditions, including alkaline, acidic and direct contact with cement environments. Based on the results, design considerations are provided for AF membrane applications.

Design of pressure-sensitive adhesive suitable for the preparation of transdermal patches by hot-melt printing.

This work aimed to design low-melting pressure sensitive adhesives and to demonstrate the feasibility of the preparation of (trans)dermal patches by hot-melt ram extrusion printing. This approach allows defining both the geometry of (trans)dermal patch and the drug strength easily according to patient needs. The preparation steps are the mixing of a poly-ammonium methacrylate polymer (i.e. Eudragit RL and RS) with a suitable amount of plasticizer (triacetin or tributyl citrate) and drug (ketoprofen or nicotine), the melting in the ram extruder, and the printing on the backing layer foil. The formulations were characterized in terms of rheological and adhesive properties, in vitro drug release and skin permeation profiles. The (trans)dermal patches made of Eudragit RL or Eudragit RS plasticized with the 40% triacetin could be printed at 90°C giving formulations with suitable adhesive properties and without cold flow after 1month of storage at 40°C. Furthermore, the overall results showed that the performances of printed (trans)dermal patches overlapped those made by solvent casting, suggesting that the proposed solvent-free technology can be useful to treat cutaneous pathologies when the availability of (trans)dermal patches with size and shape that perfectly fit with the skin area affected by the disease improves the safety of the pharmacological treatment.

Characterization of accumulative fold-forged magnesium-nickel multilayered composite structures

The newly developed severe plastic deformation (SPD) process of accumulative fold forging (AFF) was implemented for the production of multilayered composite structures by incorporating magnesium powder between nickel foil layers. The process was carried out up to 20 folding steps to produce a composite structure with more than a million number layers. By controlling the content of introduced magnesium powder and cyclic repeating of fold-forging steps, a reverse composite of magnesium matrix reinforced by fragments of nickel foil layers was produced. Microstructural characterization according was conducted using channeling contrast imaging by field emission-scanning electron microscopy (FE-SEM) and focused ion beam (FIB)/transmission electron microscopy (TEM) analyses, which revealed the formation of ultra-fine grains (UFG) with the average sizes of ~900 and 400 nm in the magnesium matrix and nickel foil layers, respectively. Moreover, a well-bonded structure was characterized at the interface of nickel folded layers and magnesium matrix was noted as a result of severe plastic shear straining during the AFF process as well as the deformation-assisted elemental inter-diffusion across the interface. Mechanical behavior of the produced multilayers composite structure was interrogated by indentation micro-hardness testing while displayed a fluctuation of hardness profile across the layers depending on the location of the micro-indenter. Considerable hardness improvements up to maximum values of ~300 and 60 HV are noted for the nickel layers and magnesium matrix, respectively, i.e., increases of around 100% compared to the primary annealed state of these metals as a result of the microstructural refinements.

Effect of Sn interlayer on mechanical properties and microstructure in Al/Mg friction stir lap welding with different rotational speeds

The effect of Sn foil layers on the mechanical properties and microstructure of friction stir lap welded 5052 aluminium alloy and AZ31B magnesium alloy was explored in this study. Models of numerous joints were set by different rotational (700, 900, 1100, 1300 and 1500 rpm) and welding speeds (50 mm min−1). Mg/Al dissimilar lap joints with and without Sn interlayer were produced by friction stir lap welding. The results suggest that Mg2Sn intermetallic compounds formed instead of Mg17Al12 and Mg2Al3 intermetallic compounds. In direct welding, the joint are only connected by metallurgical bonding between atoms (Mg/Al). In solder joints with Sn interlayer, the joint is connected by the combined effect of metallurgical bonding between atoms (Mg/Sn, Al/Sn) and interface mechanical coupling. For the joint with Sn interlayer, the maximum fracture load of the joint with the Sn interlayer reached 3.72 kN at a rotational speed of 900 rpm. As the rotational speed is increased from 1300 rpm to 1500 rpm, the Sn content on the the advancing side and the retreating side is more, resulting in more Mg2Sn crystal content, increased crack content. The joint performance gradually decreases. For the joint without a Sn interlayer, the microscopic morphology was a river-like pattern, which was characterized by brittle fracture. For a joint with a Sn interlayer, the microscopic morphology contained micro-dimples and a small quantity of inclusions, which were characterized by mixed fracture.

Mode I fracture toughness of hybrid co-cured Al-CFRP and NiTi-CFRP interfaces: An experimental and computational study

In the spirit of advancing joining concepts as well as adoption of hybrid composites, the interface of a metallic foil and carbon fabric reinforced polymer matrix composite was explored experimentally and computationally. An out-of-autoclave manufacturing method, double-infusion VARTM, was successfully employed to create a hybrid composite laminate that was composed of a layer of metal foil (Al or NiTi) placed at the center of sixteen layer plain weave T300 carbon fabric with epoxy Epikote-Epikure 04908 matrix. The fracture behavior was obtained via the Double Cantilever Beam (DCB) tests at room and elevated temperatures and were monitored on-line using Rayleigh backscattering fiber optics technique. Distributed strain profiles were measured on both at the top and bottom surfaces of the specimen to validate/assist computational models. This new technique to measure distributed strains in-situ during testing has introduced a new dimension to the visualization of strain energy release upon crack propagation.The virtual crack closure method was employed to simulate crack propagation at the hybrid interface. The experimental results revealed the dominant mode of failure as cohesive. Load-displacement and strain profiles measured from the experiments were in good agreement with the numerical results. The foremost research highlight is the novel integration of computational simulation with fiber optics Distributed Strain System (DSS) in DCB experiments to elucidate crack growth at a hybrid interface.

Influence of Interface Layer on the Properties of Exploding Foil Flyer Generator by Integrating Al/Ni Multilayers

Reactive multilayer films (RMFs) are a type of a thermite nanoenergetic multilayer film, which can be potentially applied to an exploding foil flyer generator (EFFG). Herein, Al/Ni RMFs with a bilayer thickness of 500 nm are integrated into an exploding foil layer by a magnetron sputtering method. The effects of interface layer on the properties of the EFFG are systematically investigated in terms of the electrical behavior and flyer velocity. The interface layer is controlled by annealing, whose structure and chemical composition are confirmed by X‐ray diffraction and transmission electron microscopy. The periodic multilayer structure can be clearly visible, and the thickness of interface layer increases with increasing annealing temperatures from room temperature to 573 K. The EFFG integrating as‐deposited Al/Ni RMFs exhibits improved exploding properties with a short exploding time, violent explosion region, and high flyer velocity phenomenon in comparison with generator at 573 K. Overall, the EFFGs integrated Al/Ni RMFs with larger interface layers can decrease the electrical plasma performances, which are significant for investigating the applicability in various engineering fields.

Setting of Natural Fracture Splitting Surface on Connecting Rod and Its Formation Mechanism

To break through the limitation of fracture splitting process on material selection and solve problems during fracture splitting such as parts tearing, failing to split, dropping dregs, fracture surface deformation and so on, a new technique of setting natural splitting surface in casting blank is proposed, aiming to achieve brittle fracture along pre-set surface during fracture splitting process. In this research, casting blanks are produced with metal molds. A layer of AZ31 foil is set in advance before casting, the layer interacts with liquid LD10 aluminum alloy, forming a brittle interface layer across the whole casting, then a fracture splitting hole is machined in the middle of the casting blank and cracking grooves are machined on the inner hole near the interface to achieve fracture splitting. Experiment revealed that the initial crack on the specimen starts from the root of the cracking groove, and the crack basically expands along the pre-set fracture splitting surface. The fracture surface is characterized by flaky brittle fracture. There is residual magnesium and pellumina, which have characteristics of melt with low-melting point, and micro-porosity in the fracture. Further analysis suggests that the formation mechanism of a natural fracture splitting surface can be described as follows: the magnesium foil with strong oxidation in high-temperature alloy liquid interacts with the pellumina at the front of liquid flow, which forms a interface. Meanwhile a layer of melt with a low-melting point forming as a result of interface reaction is pushed to the edge of the grain boundary, and surface liquid film shrinks to be micro-porosity. With such a combined effect it finally forms the brittle surface, which provides the condition for conducting subsequent fracture splitting process.

A Chemically Polished Zinc Metal Electrode with a Ridge-like Structure for Cycle-Stable Aqueous Batteries.

Aqueous rechargeable zinc (Zn) metal batteries show great application prospects in grid-scale energy storage devices due to their good safety, low cost, and considerable energy density. However, the electrical and topographical inhomogeneity caused by the native passivation layer of metallic Zn foil leads to inhomogeneous electrochemical plating and stripping of metallic Zn, and the limited accessible area to the electrolyte of the regular foil electrode causes the poor rate capability, which together hinder the practical application of the Zn metal electrode in rechargeable aqueous batteries. In this work, we show that the native passivation layer on the Zn foil electrode can be removed by a simple chemical polishing strategy, associated with the formation of a three-dimensional ridge-like structure of metallic Zn (r-Zn) on the surface of the Zn foil electrode due to the selective etching of weak crystallographic planes and grain boundary of metallic Zn. The clean and uniform surface of the metallic Zn electrode enables homogeneous plating and stripping of metallic Zn, and the ridge-like structure of r-Zn increases the accessible surface area to the electrolyte and reduces the local current density, which elevates the electrochemical performance of the Zn metal anode with regard to the cycling stability and rate capability. It is demonstrated that a r-Zn anode cycles stably for over 200 h at 1 mA cm-2 and 0.5 mA h cm-2 with a low overpotential of 20 mV, which far outperforms 39 h of cycling with an overpotential of 72 mV for its pristine metallic Zn counterpart.

Modern Biodegradable Plastics-Processing and Properties: Part I.

This paper presents a characterization of a plastic extrusion process and the selected properties of three biodegradable plastic types, in comparison with LDPE (low-density polyethylene). The four plastics include: LDPE, commercial name Malen E FABS 23-D022; potato starch based plastic (TPS-P), BIOPLAST GF 106/02; corn starch based plastic (TPS-C), BioComp®BF 01HP; and a polylactic acid (polylactide) plastic (PLA), BioComp®BF 7210. Plastic films with determined geometric parameters (thickness of the foil layer and width of the flattened foil sleeve) were produced from these materials (at individually defined processing temperatures), using blown film extrusion, by applying different extrusion screw speeds. The produced plastic films were tested to determine the geometrical features, MFR (melt flow rate), blow-up ratio, draw down ratio, mass flow rate, and exit velocity. The tests were complemented by thermogravimetry, differential scanning calorimetry, and chemical structure analysis. It was found that the biodegradable films were extruded at higher rate and mass flow rate than LDPE; the lowest thermal stability was ascertained for the film samples extruded from TPS-C and TPS-P, and that all tested biodegradable plastics contained polyethylene.

Mechanical analysis and design of flexible beads-and-thread lithium-ion battery

Novel beads-and-thread structural designs have been applied in the new-generation flexible lithium-ion batteries (LIBs) to achieve high electrochemical performance and high flexibility simultaneously. However, to understand the mechanical degradation and to obtain the best performance of these flexible LIBs, the structural analysis and design of such LIBs are of crucial importance. Accordingly, it is necessary to establish detailed and systematic analytic and simulation models to describe the mechanical behavior of these LIBs. Here, the flexibility, energy density, and safety criterion of beads-and-thread LIBs are quantitatively discussed by an analytic finite deformation model and a finite element analysis (FEA) model. The trade-off between effective flexibility and relative energy density of LIBs has been discussed with the parametrical study of two key geometric parameters, length ratio and winding layer number of the structural element. Stress/strain analysis reveals the yield of the Al foil layer in unwound part could be a safe criterion for evaluating mechanical degradation of the battery. Rational design diagrams of flexibility and relative energy density are investigated for the battery designers, considering the balance of battery safety, mechanical and energy storage properties. This work is expected to provide the design guidelines for flexible beads-and-thread LIBs.

Graphene oxide as a radiation sensitive material for XPS dosimetry

The suitability of graphene oxide (GO) foils as radiation sensitive materials for soft X-ray irradiation is investigated by means of X-ray photoelectron spectroscopy (XPS). In particular GO micrometric foils have been irradiated by soft X-rays at a 1486.6 eV energy at high flux (>1012 photons/cm2s) in ultra-high vacuum. The XPS analysis of the carbon-carbon (CC) and the carbon-oxygen links (CO) characterizes the composition of the first layers of the GO foils. The CC/CO ratio of the high-resolution C1s XPS spectrum is used as dosimetric index. The incident X-ray photons, proportionally to their fluence, partially reduce GO foils decreasing the amount of oxygen groups chemically bonded to carbon network. This decrease causes an increase on the CC/CO ratio that is correlated to the irradiation time, i.e. to the dose absorbed by the GO foil, showing a linear increment with the dose. Our preliminary investigations indicate that GO can be employed to realize a thin foil dosimeter giving a linear response to the absorbed dose in the (275.76 kGy ÷ 8.02 MGy) range. The absorbed dose can be also evaluated by measuring the C/O ratio from the C1s and O1s XPS spectra analysis or with different techniques, as discussed in the paper.