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Flame retardant modification of leaf fibers was carried out to solve the technical problem of poor fire resistance of plant fibers and improve the utilization rate of urban fallen leaves in building materials. The modification scheme adopts three flame retardants, i.e., ammonium polyphosphate (APP), magnesium hydroxide (MH), and aluminum hydroxide (ATH), and two covering layers, i.e., pure acrylic polymer lotion and water glass (Na2O · nSiO2) solution. The modified leaf fiber's combustion behavior and pyrolysis properties were tested and analyzed. The physical and mechanical characteristics, as well as the thermal insulation qualities, of leaf fiber cement-based composites (LFCC) were studied at high temperatures. The findings revealed that the three flame retardants had an effect on the chemical structure of leaf fibers. In comparison to leaf fibers without flame-retardant modification, flame-retardant-modified leaf fibers have a much greater thermal stability. and its LOI is greater than 27.0%, which is a fire-retardant material. Except for the sample with water glass as the modified cover layer, at high temperatures, the composite flame-retardant fiber LFCC's mass-loss rate is lower compared with fibers without flame-retardant modification or fibers modified with only one kind of flame-retardant. In the composite flame-retardant modified fiber LFCC, the samples with better strength at high temperature are those with ATH replacing 30% and 50% MH. The thermal conductivity of LFCC is negatively correlated with the range of temperature change.

The concentrations of small microplastics (diameter

In this paper, a new type of unit dew-point evaporative cooler with fibrous membrane was designed and constructed. The effects of three air state parameters (temperature, humidity, air velocity) on the outlet air temperature, wet-bulb efficiency and dew-point efficiency were studied, as well as the regional adaptability in four typical cities in China. The porous fibrous membrane can be used to improve the moisture permeability and diffusion characteristics of the wet channel. It was found that the wicking height rate of the porous fibrous membrane was 0.203 cm/min, the diffusivity rate was 0.118 cm2/s, which was better than the performance of Kraft Paper. The usage of this novel device in Urumqi and Lanzhou, as regions with lower relative humidity, showed better regional adaptability than in Beijing and Shanghai with higher relative humidity. When the inlet air velocity was 1 m/s, the temperature decreased from 33.4 °C to 24.2 °C and 31.3 °C–24.5 °C respectively in the former area, while, decreased from 33.6 °C to 28.1 °C and 34.6 °C–29.5 °C respectively in the latter area. With the inlet air velocity increasing from 1 m/s to 3 m/s, the outlet air temperature would rise, and the wet-bulb efficiency and dew-point efficiency would decrease, but the cooling capacity would increase.