More metal fiber content of blended electromagnetic shielding (EMS) fabric results in higher shielding effectiveness (SE) of the fabric. However, there is little information about the influence of the metal fiber content on the SE considering the fabric structure. This study constructs an index of metal fiber content per unit area (MFCPUA), and discusses the influence of the metal fiber content on the SE of the EMS fabric when fabric parameters are changed. Computations for the MFCPUA and the thickness and porosity of the metal fiber arrangement are given, and then experiments are designed to test the SE of different EMS fabric samples. According to the experimental results, the influence of the MFCPUA on the SE is analyzed and influence mechanism is discussed when the fabric weaves, emission frequencies and weft and warp densities are changed. The results show that the MFCPUA and the SE are in positive increase relation; the frequency and the SE are in the negative increase relation when the metal fiber content is unchanged. The influence of the fabric weave type on the SE depends on the length of the yarn floats; the SE values of fabric with the same weave are the same when the MFCPUA is the same regardless of the fabric density.

We report a brand new recycling route of waste marble powder, by means of surface modification with homemade nano-TiO 2 particles to produce low cost coating materials for the application in air quality improvement. The as-prepared nano-TiO 2 in anatase phase exhibits excellent photocatalytic characteristic, reflected by the high degradation rate of over 95% of methylene blue within 6 hours of UV irradiation. The prepared coating consisting of nano-TiO 2 clad marble powder was tested by monitoring the decomposition rate of formaldehyde gas. A high degradation efficiency of about 95% within 9 hours of illumination is achieved, demonstrating a promising potential for removing the harmful and toxic organic pollutants in air while applying this coating in buildings both interiorly and exteriorly.

Purpose – The purpose of this paper is to explore the influence of hole on shielding effectiveness (SE) of electromagnetic shielding (EMS) fabric under incident polarization wave, and to propose a “Key Size” theory to explain the influence mechanism. Design/methodology/approach – “Key Size” parameters describing hole shape are established, and a number of representative samples with rectangular and oval holes are made. SE of the samples are tested by waveguide testing system. Influence of the hole on the SE of the samples is analyzed according to vertical or horizontal maximum size and polarization wave direction. Finally, the “Key Size theory” and “Secondary Size theory” are proposed to explain the influencing mechanism. Findings – The hole influences on the SE are related to the vertical and the horizontal maximum size of the holes and the direction of the polarization wave. As the direction of the polarization wave is vertical (or horizontal), greater maximum size results in lower SE. As the maximum size is constant, greater maximum size causes lower SE. As the maximum size reaches to a certain value, a dividing point of the SE occurs. As the direction of the polarization wave is consistent with the direction of the maximum size, same hole area results in same SE. Originality/value – The explored influences and mechanism provide an important guiding reference for the hole design of the EMS fabric, and can be applied to the holes design of the EMS garment, composite materials, and tents.

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