scholarly journals Performance Characterization of Broad Band Sustainable Sound Absorbers Made of Almond Skins

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5474
Author(s):  
Stefania Liuzzi ◽  
Chiara Rubino ◽  
Pietro Stefanizzi ◽  
Francesco Martellotta

In order to limit the environmental impact caused by the use of non-renewable resources, a growing research interest is currently being shown in the reuse of agricultural by-products as new raw materials for green building panels. Moreover, the European directives impose the goal of sustainability supporting the investigation of passive solutions for the reduction of energy consumption. Thus, the promotion of innovative building materials for the enhancement of acoustic and thermal insulation of the buildings is an important issue. The aim of the present research was to evaluate the physical, acoustical, and thermal performances of building panels produced by almond skin residues, derived from the industrial processing of almonds. In this paper different mix designs were investigated using polyvinyl acetate glue and gum Arabic solution as binders. Air-flow resistivity σ and normal incidence sound absorption coefficient α were measured by means of a standing wave tube. Thermal conductivity λ, thermal diffusivity α, volumetric heat capacity ρc were measured using a transient plane source device. Finally, water vapor permeability δp was experimentally determined using the dry cup method. Furthermore, a physical characterization of the specimens in terms of bulk density ρb and porosity η allowed to study the correlation existing between the binder and the aggregates and the consequent acoustical and hygrothermal behavior occurring on the different mix designs. The achieved results suggested the investigated materials comparable to the main products currently existing on the market.

e-Polymers ◽  
2020 ◽  
Vol 21 (1) ◽  
pp. 038-046
Author(s):  
Xu Yan ◽  
Wanru Zhou ◽  
Xiaojun Ma ◽  
Binqing Sun

Abstract In this study, a poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) modified with nano-montmorillonite biocomposite (MMT/PHBH) was fabricated by solution-casting method. The results showed that the addition of MMT increased the crystallinity and the number of spherulites, which indicated that MMT was an effective nucleating agent for PHBH. The maximum decomposition peak of the biocomposites moved to a high temperature and residue presented an increasing trend. The biocomposites showed the best thermal stability at 1 wt% MMT. Compared with PHBH, 182.5% and 111.2% improvement in elastic modulus and tensile strength were obtained, respectively. Moreover, the oxygen permeability coefficient and the water vapor permeability of MMT/PHBH biocomposites decreased by 43.9% and 6.9%, respectively. It was also found that the simultaneous enhancements on the crystallizing, thermal stability, mechanical, and barrier properties of biocomposites were mainly caused by the formation of intercalated structure between PHBH and MMT.


Coatings ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 384
Author(s):  
Juan Tirado-Gallegos ◽  
Paul Zamudio-Flores ◽  
José Ornelas-Paz ◽  
Claudio Rios-Velasco ◽  
Guadalupe Olivas Orozco ◽  
...  

Apple starch films were obtained from apples harvested at 60, 70, 80 and 90 days after full bloom (DAFB). Mechanical properties and water vapor permeability (WVP) were evaluated. The apple starch films at 70 DAFB presented higher values in the variables of tensile strength (8.12 MPa), elastic modulus (3.10 MPa) and lower values of water vapor permeability (6.77 × 10−11 g m−1 s−1 Pa−1) than apple starch films from apples harvested at 60, 80 and 90 DAFB. Therefore, these films were chosen to continue the study incorporating ellagic acid (EA). The EA was added at three concentrations [0.02% (FILM-EA0.02%), 0.05% (FILM-EA0.05%) and 0.1% (FILM-EA0.1%) w/w] and compared with the apple starch films without EA (FILM-Control). The films were characterized by their physicochemical, optical, morphological and mechanical properties. Their thermal stability and antioxidant capacity were also evaluated. The FILM-Control and FILM-EA0.02% showed a uniform surface, while FILM-EA0.05% and FILM-EA0.1% showed a rough surface and insoluble EA particles. Compared to FILM-Control, EA modified the values of tensile strength, elasticity modulus and elongation at break. The antioxidant capacity increased as EA concentration did. EA incorporation allowed obtaining films with higher antioxidant capacity, capable of blocking UV light with better mechanical properties than film without EA.


2016 ◽  
Vol 88 (3) ◽  
pp. 275-292 ◽  
Author(s):  
Jefferson M Souza ◽  
Sandra Sampaio ◽  
Welter C Silva ◽  
Sidney G de Lima ◽  
Andrea Zille ◽  
...  

Eight functional single jersey plain knitted fabrics have been developed in order to assess a quantitative analysis of various comfort-related properties in terms of thermal control, air and water vapor permeability, wickability, coefficient of kinetic friction and antimicrobial efficiency, using eight different commercially available functional yarns: Polyester Craque® and viscose Craque® conventional yarns as controls; Finecool® and Coolmax® polyester yarns for moisture management and quick drying; Holofiber® polyester yarns containing an optical responsive material that the producer claims to improve body oxygenation; Airclo® polyester hollow yarns for efficient control of body temperature; and, finally, polyester Trevira® and viscose Seacell® for antimicrobial activity. According to the results, Coolmax® for moisture management, Airclo® for thermal control and Seacell® for antimicrobial activity present the best performances as technical textiles for sportswear for the respective specific functional property.


2021 ◽  
Author(s):  
Aritra Sinha

Abstract This study focuses on the development and characterization of a novel biodegradable edible film made from soy protein isolate enriched with alginate-glycyrrhizin nanogel(GL-ALG NGP). Nanoparticles of particle sizes below 100 nm were synthesized using glycyrrhizin(GL), calcium chloride and, sodium alginate(SA) through the reverse micro-emulsion/internal gelation method. Soy protein isolate (SPI) based films were prepared by a simple casting procedure by incorporating GL-ALG NGPs in SPI solution in different ratios of (SPI: GL-ALG NGPs) 5:0, 5:1, 2:1, 1:1, and 1:1.5. Glycerol was used as a plasticizer in the film-forming solution. The effects of the proportions of GL-ALG NGPs addition on the thickness, mechanical properties, water vapor permeability, UV barrier performance, antioxidant activity, and antimicrobial property of the obtained films were studied. The GL-ALG NGPs were analyzed using Dynamic Light Scattering. Microstructural studies of obtained films were performed using Scanning Electron microscopy. Results show incorporation of GL-ALG NGPs in soy protein-alginate complex produced smoother, compact, and more continuous matrices as compared to pure SPI films. The test results indicated that blending of SPI with GL-ALG NGPs in the ratio 1:1 increased tensile strength of obtained films by 185%, reduced water solubility to 23.59%, and water vapor permeability to 0.3087 g-mm/m2-d-kPa. Obtained films exhibited good UV barrier performance, antioxidant activity and inhibited the growth of E. coli, S. aureus, Enterobacter sakazakii, and A. niger. So, soy protein isolate-based films enriched with GL-ALG NGPs are active biodegradable edible films that can be used to extend the shelf life of food products.


2020 ◽  
Vol 330 ◽  
pp. 01030
Author(s):  
Meriem Saidi ◽  
Amel Soukaina Cherif ◽  
Ezeddine Sediki ◽  
Belkacem Zeghmati

Bio-based building materials such as earth bricks are attracting renewed interest throughout the world due to their thermal and environmental properties. In this work, a numerical study of the hygrothermal behavior of building walls consist of compressed earth bricks (CEB) and stabilized earth bricks (SEB) was performed. A two-dimensional Luikov model for evaluating the temperature and the moisture migration in porous building materials was proposed. The coupled heat and moisture transfer problem was modeled. The governing equations of a mathematical model were solved numerically with the finite difference method. Input parameters in the model and their dependency on stabilizers content were determined by laboratory experiments. In order to specify the effect of chemical stabilization on the heat and mass transfer within studied materials, average moisture content and temperature were presented as a function of time. Results show that the addition of chemical stabilizers enhances the heat transfer through the earthen materials and reduces their water vapor permeability.


2021 ◽  
Author(s):  
Saba Ghasemizad ◽  
Sajad Pirsa ◽  
Saber Amiri ◽  
Parisa Abdosatri

Abstract In this paper, the effect of adding gum Arabic at levels of 0-5%, and chromium oxide nanoparticles (Cr2O3 NPs) at levels of 0-3%, are investigated on orange peel-based films. The obtained results reveal a significant increase (p<0.05) in water vapor permeability, weight loss, tensile strength, and Young's modulus of film samples by increasing the percentage of both gum and nanoparticles. Moreover, the addition of gum Arabic and Cr2O3 NPs decreases the thickness, water-solubility, L*, a*, b* indexes while increasing the elongation to the breaking point. Furthermore, the moisture content of the film samples was decreased by the addition of nanoparticles, however, the addition of gum Arabic increased this parameter. The obtained results from the morphology of the samples indicated an increase in both roughness and cracks by increasing the percentage of nanoparticles as well as creating a smooth surface with the addition of gum Arabic. Besides, the results of FTIR revealed no new peak in the prepared samples, as compared to the control sample. The results of XRD indicated that the addition of gum Arabic and nanoparticles simultaneously caused the formation of new crystals and increasing the crystallinity of the films. Based on TGA results, the thermal stability of films containing the nanoparticles increased, as compared to the control sample. In the meantime, the addition of gum and nanoparticles increased the antimicrobial properties of the film samples, as compared to the control. Overall, those films created by the orange peel including gum Arabic and Cr2O3 NPs could enhance the mechanical properties and water vapor permeability of the samples.


Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 1986 ◽  
Author(s):  
Shaoxiang Lee ◽  
Yunna Lei ◽  
Dong Wang ◽  
Chunxu Li ◽  
Jiaji Cheng ◽  
...  

ZIF-8 nanoparticle-doped polyvinyl alcohol (PVA)-S-MC films were prepared via casting method. The effect of different concentrations of ZIF-8 on the physical properties and structural characterization of the films were investigated. The results indicated that ZIF-8 could increase the water resistance and mechanical property of the membrane. Through FTIR, scanning electron microscope (SEM), atomic force microscope (AFM), and TGA analysis, it was found that ZIF-8 changed the phenomenon of macromolecule agglomeration and improved the thermal stability of the membrane. The breathable behavior of the film was also studied through oxygen permeability and water vapor permeability analysis. The result illustrated that the breathability of the film improved significantly by adding ZIF-8. The maximum reached when the weight ratio of ZIF-8 was 0.01 wt %. The property expands the application of PVA/starch blend film in the postharvest technology of fruits and vegetables.


Coatings ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 84
Author(s):  
Sijun Ma ◽  
Yuanrong Zheng ◽  
Ran Zhou ◽  
Ming Ma

Four kinds of edible composite films based on chitosan combined with additional substances (konjac glucomannan, cassava starch, maltodextrin and gelatin) and the addition of lysozyme were prepared and used as packaging materials for Mongolian cheese. The prepared composite films were evaluated using scanning electron microscopy and Fourier transform infrared spectroscopy. The physicochemical properties of all chitosan composite films, including thickness, viscosity, opacity, color, moisture content, water vapor permeability, tensile strength and elongation at break, were measured. The results show that Konjac glucomannan–chitosan composite film presented the strongest mechanical property and highest transparency. The cassava starch–chitosan composite film presented the highest water barrier property. The study on the storage characteristics of Mongolian cheese was evaluated at 4 °C. The results show that the cheese packaging by cassava starch–chitosan composite film presented better treatment performance in maintaining the quality, reducing weight loss and delayering microbial growth.


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