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Measurement
Published in Carl Hopkins, Sound Insulation, 2020
Time dependency occurs with some soft floor coverings. During each impact the tapping machine hammers can increase or decrease the contact stiffness and damping properties of the soft floor covering directly underneath the hammers. Hence the power input from the tapping machine changes with time due to variation in the physical properties of the floor covering. This can occur with materials such as carpet (Michelsen, 1982) or felt-backed PVC (Bodlund and Jonasson, 1983). An example is shown in Fig. 3.48 for carpet on a concrete slab where the sound pressure level was measured using successive 5 s samples (Michelsen, 1982). After the tapping machine was switched on, the sound pressure levels initially increase with time in the low- and mid-frequency range before stabilizing after ≈4 min.
Advanced technical textile products
Published in T. Matsuo, Textile Progress, 2019
Bag filters are widely used for cleaning the exhaust gas from several kinds of incinerators. They are usually made of glass fiber-woven fabric or synthetic fiber needle felt or its combination with woven fabric. Polyphenylene sulfide, m-aramid, polyimide, and polyte-trafluorocarbon are typically used as the synthetic fiber material. A typical example of bag filter system is shown in Figure 6. The dust contained in exhaust gas is accumulated on the surface of a bag filter whose shape is tubular. When the inlet pressure increases up to a settled value by the layer-up of accumulated dust, it is dropped off from the bag surface by counterpulse jet or mechanical vibration. Acid gas and some other harmful gas substances can also be removed by introducing such materials as slaked lime and activated carbon in the bag.
Insulating Media
Published in Leonard L. Grigsby, Electric Power Transformer Engineering, 2017
Thomas A. Prevost, David L. Hanson, Leo J. Savio, Ted Haupert
Pressboard is made in a similar manner as paper. The pulp fiber is applied to a rotating felt using the cylinder process. The layer of wet fiber is collected on a forming cylinder until the desired thickness is achieved. It is then cut from the cylinder forming a sheet which is subsequently dried.
Compassionate design for dementia care
Published in International Journal of Design Creativity and Innovation, 2019
Cathy Treadaway, Aidan Taylor, Jac Fennell
The Giggle Balls are about the size of a tennis ball. Each one contains a small microcontroller and speaker with sound files of children giggling that are activated through a tilt switch via gentle hand movement. Laughter is contagious, particularly the sound of children’s laughter, and so the embedded sound files were intended to stimulate spontaneous joy. The balls are soft, washable, robust, safe to throw and comforting to hold. The felt was made from lambs’ wool and crafted by hand, using a combination of wet felting and needle felting. The open mouth contains a small felted inner pouch containing the electronics. This inner pouch is velcroed to the inside of the outer felt ball and is intentionally difficult to remove, to avoid becoming a choking hazard for a person living with dementia.