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Electron Beam Curing Equipment
Published in Jiri George Drobny, Radiation Technology for Polymers, 2020
The source of electrons is a thermionic cathode, which is almost always a tungsten or thoriated tungsten wire, although tantalum wire or lithium hexaboride pellets are also used as cathodes (Chrusciel, J., private communication). Electron emission is most frequently controlled by the variation of temperature of the cathode, but this can also be done by a grid with variable voltage. The beam of electrons is extracted, focused, and accelerated by an internal electric field, determined by a series of electrodes or dynodes with intermediate potentials obtained from a resistive voltage divider (Chrusciel, J., private communication). The electrons gain energy continuously throughout the length of the acceleration tube. After acceleration, the concentrated electron beam is dispersed by scanning with a time-varying magnetic field with a sweep rate of at least 100 Hz. The divergent beam so formed expands within an evacuated scan horn and then emerges into the air through a thin metallic foil. This foil is usually made from titanium, but other metals, such as aluminum alloys or titanium alloys, are used.27 In order to minimize the loss of the electron energy, the thickness of a titanium foil is kept in the range between 25 and 50 pm for electron energies above 0.5 MeV, and between 6 and 15 pm for energies below 0.3 MeV. The windows of the scanning horn may be as wide as 2 m (80 in.) (Chrusciel, J., private communication).
Steady-State Heat Transfer Measurement Techniques
Published in Je-Chin Han, Lesley M. Wright, Experimental Methods in Heat Transfer and Fluid Mechanics, 2020
As opposed to the copper plate method where the copper plate separates the fluid and the heater, with this method, the foil acts as a heater and is in direct contact with the fluid. A stainless steel or Inconel thin foil can be used as the heater. The thickness of the foil used is typically about 0.05 mm (0.002″). A thin foil is desired as it reduces lateral heat conduction in the foil. However, thinner foils are difficult to handle and tend to get damaged easily. The foil is cut to the desired shape and mounted on a substrate. The substrate is typically a material with low conductivity such as polystyrene or Plexiglas.
Filter Components—the Capacitor
Published in Richard Lee Ozenbaugh, Timothy M. Pullen, EMI Filter Design, 2017
Richard Lee Ozenbaugh, Timothy M. Pullen
The two subgroups are metallized and foil. For the metallized style, the dielectric is coated with a thin spray of metallized aluminum that becomes the plate of the capacitor. The other subgroup is aluminum foil. The typical aluminum foil thickness is 0.00023 inch, or 0.23 mil. This foil is much thicker than the film, which is measured in microns. Foil will carry much more current and is therefore better for pulse applications and EMI filters where there are high harmonic currents from off-line regulators and similar harmonic sources. Most EMI filters are built with this type of construction and have a thicker aluminum foil if higher currents are expected. Just as the dielectric can have several layers for higher voltages, the foil can either be thicker or also layered. The metallized film has several advantages, however. This capacitor can be much smaller for the same capacitor value, and this type is self-healing. All dielectrics have small pinholes throughout their length. When the applied voltage stresses the film, the film often shorts out through one of the pinholes, causing the film to melt. The aluminum on the metallized film will then re-form, making the capacitor self-healing. Another advantage of this subgroup is that the aluminum can be sprayed on both sides of the metallized dielectric. This adds to the smaller size, promotes self-healing, and is better for extended life.
Jet impingement technique for heat transfer enhancement: Discovering future research trends
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2023
Yashwant Singh Bisht, Shiv Dayal Pandey, Sunil Chamoli
An experimental setup, which is similar to the authors’ past investigations on jet impingement, is shown schematically in Figure 9, and its use in the current work (Deo, Chander, and Saini 2016; Patel and Lanjewar 2019). A single supply of air is divided into two sections, with a pressure regulator being utilized in each. Digital mass flow controllers use to regulate the flow rate of air (Alicate – MCR−2000SLPM-D-PAR). To achieve a fully swirling flow profile at exit of pipes, circular nozzles are constructed using 100d-long aluminum pipes. A a 3 mm thick smooth circular tube was wrapped with a 25-mm thick SS 304 foil for a resistance heater to achieve a steady heat flux at the target surface. Foil has a thermal conductivity of 16 W/m K. To decrease axial and circumferential heat conduction, thin foil is used. The foil covering the phenolic tube firmly fastened using double-sided sticky tape measuring 50 lm. To reduce convective heat transmission, glass wool was used within the phenolic tube’s hollow region ks = 0.02 W/mK (Figure 10a).
Peeling of metal foil from a compliant substrate
Published in The Journal of Adhesion, 2021
The materials tested are the constituent of liquid food packaging with multiple layer of films and foils (Figure 1). The most widely used packaging materials in liquid food packaging industries are LDPE, Al-foil and paper board. Each of the layers of a package has its own role. For example, the paperboard, which is considerably thicker than the other layers, bears the load when the package is filled, folded and gripped, while the Al-foil isolates the liquid inside from light and diffusion.[8] The outer decor layer of LDPE protects the paper and print on it from moisture-related damage. It is important that the inside layer which is in contact with the product inside does not react or dissolve with it and contaminate the product during its expected lifetime. LDPE layers are used to serve this purpose. The layers are combined together in several steps. The Al-foil is produced by thinning Al-sheets by rolling them several times. Also, during the manufacturing process, LDPE is extruded and rolled with other layers. The laminate of LDPE film and Al-foil are most important among the layers. The adhesion between them dictates the load carrying capacity and allowable strain in the laminate. This makes the study of adhesion between them very important in packaging applications and many previous works have addressed this phenomenon.[3,4,6,7,34–37]
Sustainable requirements and value proposition for milk Ultra-high temperature (UHT) packaging
Published in Supply Chain Forum: An International Journal, 2020
Cristian Camilo Aparicio-Peralta, Ana X. Halabi-Echeverry, Alejandro Puentes-Parodi
The eco-design set of tools makes it possible to judge and compare different product concepts based on characteristics such as a) energy, b) recyclability, c) hazardous waste content, e) durability, f) repairability and g) price. Energy comparisons can compromise the eco-design result when the amount of energy used to manufacture the material is unknown. Since these tools compromise the environmental concept of the product, from the starting point related to manufacturing up to the point of usage, recycling and disposal, it is necessary to increase the service possibilities of the materials understanding current packages (rigid and flexible forms). Figure 4 shows the regular composition of Tetrapack® rigid packaging, which consists of different layers that provide durability and portability to food:Paperboard: Is the main material in cartons. It provides stability, strength and smoothness to the printing surface.Polyethylene: Protects against outside moisture and enables the paperboard to stick to the aluminium foil.Aluminium foil: Protects against oxygen and light to maintain the nutritional value and flavours of the food in the package in ambient temperatures.