Noise is a complex sound without periodic character which affects biological and psychological state of humans and other organisms in nature. This paper presents research on the sound-absorbing properties of new types of ecological composite materials reinforced with various wastes that can harm the environment. Sound absorbing capacity for new composites depends on the proportion and nature of the waste used. The absorption coefficient was determined for each sample in order to characterize the sound-absorbing capacity for each composite material obtained and the reinforcement material influences on the sound absorbing properties.
The aim of this study was to determine the chemical composition of wet depositions in two locations from urban and rural area near Bucharest from January to May 2017. For all the samples, pH, conductivity, anions, cations and heavy metals were determined. For anions (Cl -, NO3 -and SO4 2-) and cations (Ca 2+ , K + , Mg 2+ , Na 2+ ) determination an ion chromatographic method was used. Heavy metals (Co, Cr, Cu, Mn, Ni, Pb and Zn) were determined using AAS with flame and graphite chamber. Results showed the presence of the interested compounds in wet depositions samples with SO42-and Ca 2+ as the dominant anion and cation. Heavy metals concentration followed the trend: Zn > Mn > Cu > Pb > Ni > Cr > Co. Analysing the results obtained the potential sources of ambient air pollution were also suggested.
Sustainable materials made from recycled materials are an alternative to traditional materials (synthetic ones) and present a lower environmental impact. Due to the fact that natural fibers were successfully used to produce environmentally friendly sound adsorbing materials, biocomposites made from recycled polypropylene (PPR), feathers flour (FF) with / without compatibilizers (C) were obtained and characterized from the point of view of their acoustical behavior. Obtained materials were characterized also from the morphological and compositional point of view by scanning electron microscopy and thermal gravimetric analysis. All tested samples presented sound adsorption properties but the best results were obtained for the biocomposites with FF content of 10%-20%.
Composite manufacturing from plastic wastes of polyethylene terephthalate (PET) type, sand-blasting represents a material recovery of the wastes. This process can be achieved, with the purpose of reducing the material consumption which is in deficit, production costs, and the duration of the technological processes. Thermoplastics composites obtained by a melting process at 170-200 o C, wastes incorporation and solidification in forms replace successfully the thermo rigid composites obtained from resins after a complicated technological process. So, it could be recovered, with minimal efforts, under reduced toxicological environmental conditions and extremely reduced energy consumptions, a significant variety of wastes, with related economical and ecological advantages. The paper presents the obtaining of thermoplastic material from PET wastes, sand, structurally evaluated and measured after the physical and mechanical properties.
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