| 1. |
- Duan, Yumin, et al.
(författare)
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Succession of keratin-degrading bacteria and associated health risks during pig manure composting
- 2020
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Ingår i: Journal of Cleaner Production. - : Elsevier. - 0959-6526 .- 1879-1786. ; 258
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Tidskriftsartikel (refereegranskat)abstract
- The alteration of microbial dynamics and their divergence were evaluated in bristles containing pig manure (PM) compost with different concentrations of coconut shell biochar [0% (T1), 2.5% (T2), 5.0% (T3), 7.5% (T4) and 10% (T5)] amendment. The results revealed that the CB amendment significantly increased the keratin degradation efficiency and bacterial diversity during composting. The richest bacterial diversity and the highest keratin reduction of 39.1% were observed in the PM compost with a 7.5% CB amendment. The most abundant phyla were Firmicutes and Actinobacteria (which accounted for 87.91% and 12.09%, respectively), and the superior genera were Bacilli and Clostridia (which accounted for 23.52% and 61.17%, respectively). In addition, a dimensionality analysis from principal coordinate’s analysis and non-metric multidimensional scaling showed that the bacterial community had a significant divergence among the different dosages of CB. Furthermore, the correlation found in a canonical correspondence analysis illustrated that the physio-chemical environmental factors were more relevant for the bacterial community within the CB in the compost than in that in the control sample. Overall, the application of biochar for composting altered the typical selectivity for functional bacteria and further influenced the organic waste biotransformation during bristle-containing PM composting. (C) 2020 Elsevier Ltd. All rights reserved.
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| 2. |
- Mukesh Kumar, Awasthi, et al.
(författare)
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Biotechnological strategies for bio-transforming biosolid into resources toward circular bio-economy : A review
- 2022
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Ingår i: Renewable & sustainable energy reviews. - : Elsevier. - 1364-0321 .- 1879-0690. ; 156
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Forskningsöversikt (refereegranskat)abstract
- Biosolids are the biological organic matter extracted from various treatment processes of wastewater which are considered as a rich source of energy and nutrients. The most commonly used method for the disposal of biosolids is landfilling. But this causes the loss of valuable nutrients and creates environmental issues. Circular economy approaches provide a better way for utilization these resources in a sustainable manner. This allows maximum utilization of resources and many natural resources can be preserved and utilized for future generations. The present review provides a comprehensive illustration of biotechnological approaches for the utilization of biosolids. Various process strategies for the utilization of biosolids for the production of energy, fuels and valueadded products are discussed. The utilization of this rich organic matter under circular economy has also been described in detail.
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| 3. |
- Fulmali, Abhinav Omprakash, et al.
(författare)
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Water diffusion kinetics study at different hydrothermal bath temperatures and subsequent durability studies of CNT embedded fibrous polymeric composites: Roles of CNT content, functionalization and in‐situ testing temperature
- 2023
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Ingår i: Journal of Applied Polymer Science. - : Wiley. - 0021-8995 .- 1097-4628. ; 140:11
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Tidskriftsartikel (refereegranskat)abstract
- Although structural polymers like epoxy are extensively used in marine applications over metallic structures, environmental water tends to ingress into this polymer which may affect its long-term durability. The extent of degradation caused by the absorbed water on polymeric composite's mechanical properties depends on the water diffusion mechanism, environmental temperature and subsequent reversible and irreversible chemical restructuring of the polymer. In this study, hydrothermal conditioning behavior of glass fiber reinforced epoxy (GE) composites with varying (0.1, 0.3, and 0.5) wt.% of pristine and functionalized carbon nanotubes (CNTs and FCNTs) was studied at 15°C (Low-Temperature Hydrothermal Conditioning (LTHC)) and 50°C (Elevated-Temperature Hydrothermal Conditioning (ETHC)) water baths. The changes in chemical bonding characteristics and glass transition temperature of GE composite due to above mentioned factors have been studied by Fourier transformed infrared spectroscopy and differential scanning calorimetry. The gravimetric analysis was employed to monitor the water uptake kinetics of the composites and flexural strength of conditioned composites after 50 days of conditioning and saturation was study to understand the effect of water sorption. Experimental results revealed that, FCNTs greatly hinders the water absorption through the interfaces at LTHC, as the equilibrium water content of 0.1FCNT-GE composite was ~9.5% and ~3.0% and Diffusion coefficient was ~60.0% and ~15.5% lower than the GE and 0.1CNT-GE composites, respectively at LTHC. At LTHC, the water saturated 0.1FCNT-GE composites exhibited superior flexural strength than GE and 0.1CNT-GE composites. At ETHC, generation of hygroscopic stresses and unfavorable stresses at the weak CNT/polymer interface adversely affected the 0.1CNT-GE composites water resistance compared to 0.1FCNT-GE composites with stronger FCNT/polymer interface. The extent of recovery in the flexural strength was evaluated by complete desorption of water-saturated specimens. Finally, a fractography study was conducted to understand the variation in the well-being of the glass fiber/polymer and nanotube/polymer interface due to mentioned varying factors.
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| 4. |
- Kumar Ramamoorthy, Sunil, 1987-, et al.
(författare)
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Functionalization of Carbon Nanotube
- 2021
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Ingår i: Handbook of Carbon Nanotubes. - Cham : Springer. - 9783319706146
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Bokkapitel (refereegranskat)abstract
- One-dimensional carbon nanotubes (CNTs) have outstanding mechanical properties, making them a good candidate for reinforcement application in polymer and fiber-reinforced polymer composites. Superior properties of the CNTs are exploited regularly by reinforcing these nanotubes in a polymer matrix. However, strong Van der Waals interaction energy of tube-tube contact, high electrostatic interaction between the tubes, small tube size, and large surface area of the tubes render CNT dispersion a problematic task. Therefore, to improve its dispersion and alignment in the composite, researchers have developed innovative techniques to strengthen the properties of the composite. For achieving optimum and reproducible mechanical properties in a composite, fine dispersion of CNTs, their alignment, and strong interfacial adhesion with polymer is a demand to be guaranteed. In this chapter, the principles and techniques for uniform dispersion and alignment of CNTs in the polymer and fiber-reinforced polymer composite are discussed.
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| 5. |
- Akbari, Samira, et al.
(författare)
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Novel Bio-based Branched Unsaturated Polyester Resins for High-Temperature Applications
- 2023
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Ingår i: Journal of Polymers and the Environment. - 1566-2543 .- 1572-8919.
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Tidskriftsartikel (refereegranskat)abstract
- Unsaturated polyester resins, one of the most important thermosets, are invariably produced from oil-based monomers. Their application is limited in areas where high thermal stability is required due to their low Tg. Besides, these resins contain 30–40% hazardous styrene as a reactive solvent. Therefore, developing bio-based solventless unsaturated polyester resin with medium to high thermomechanical properties compared to petrochemical-based counterparts is important. In order to achieve this, a series of branched bio-based unsaturated polyester resins were synthesized using bulk polymerization method in two steps. In the first step, four different intermediates were prepared by reacting glycerol (as a core molecule) with either isosorbide (diol), 1,3-propanediol (diol), 2,5-furandicarboxylic acid (saturated diacid), or adipic acid (saturated diacid). In the second step, the branched intermediate was end capped with methacrylic anhydride to introduce reactive sites for cross-linking on the branch ends. The chemical structure of the resins was characterized by 13C-NMR. FT-IR confirmed the polycondensation reaction in the first step and the end functionalization of the resins with methacrylic anhydride in the second step. The effect of 2,5-furandicarboxylic acid and isosorbide on thermomechanical and thermal properties was investigated using dynamic mechanical analysis, differential scanning calorimetry, and thermo-gravimetric analysis. Results indicated that 2,5-furandicarboxylic acid based resins had superior thermomechanical properties compared to a commercial reference unsaturated polyester resin, making them promising resins for high-temperature composite applications. For example, the resin based on 2,5-furandicarboxylic acid and isosorbide and the resin based on 2,5-furandicarboxylic acid and 1,3-propanediol gave glass transition temperatures of 173 °C and 148 °C, respectively. Although the synthesized 2,5-furandicarboxylic acid based resins had higher viscosity (22.7 Pas) than conventional unsaturated polyester (0.4–0.5 Pas) at room temperature, preheated resins can be used for making high-temperature-tolerance fiber-reinforced composite.
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| 6. |
- Bakare, Fatimat O., et al.
(författare)
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Thermomechanical properties of bio-based composites made from a lactic acid thermoset resin and flax and flax/basalt fibre reinforcements
- 2016
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Ingår i: Composites. Part A, Applied science and manufacturing. - : Elsevier. - 1359-835X .- 1878-5840. ; 83, s. 176-184
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Tidskriftsartikel (refereegranskat)abstract
- Low viscosity thermoset bio-based resin was synthesised from lactic acid, allyl alcohol and pentaerythritol. The resin was impregnated into cellulosic fibre reinforcement from flax and basalt and then compression moulded at elevated temperature to produce thermoset composites. The mechanical properties of composites were characterised by flexural, tensile and Charpy impact testing whereas the thermal properties were analysed by dynamic mechanical thermal analysis (DMTA) and thermogravimetric analysis (TGA). The results showed a decrease in mechanical properties with increase in fibre load after 40 wt.% for the neat flax composite due to insufficient fibre wetting and an increase in mechanical properties with increase fibre load up to 60 wt.% for the flax/basalt composite. The results of the ageing test showed that the mechanical properties of the composites deteriorate with ageing; however, the flax/basalt composite had better mechanical properties after ageing than the flax composite before ageing.
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| 7. |
- Gomes Hastenreiter, Lara Lopes, et al.
(författare)
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Synthesis of Lactic Acid-Based Thermosetting Resins and Their Ageing and Biodegradability
- 2020
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Ingår i: Polymers. - : MDPI AG. - 2073-4360. ; :12, s. 1-17
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Tidskriftsartikel (refereegranskat)abstract
- The present work is focused on the synthesis of bio-based thermoset polymers and their thermo–oxidative ageing and biodegradability. Toward this aim, bio-based thermoset resins with different chemical architectures were synthesized from lactic acid by direct condensation with ethylene glycol, glycerol and pentaerythritol. The resulting branched molecules with chain lengths (n) of three were then end-functionalized with methacrylic anhydride. The chemical structures of the synthesized lactic acid derivatives were confirmed by proton nuclear magnetic resonance spectroscopy (1H-NMR) and Fourier transform infrared spectroscopy (FT–IR) before curing. To evaluate the effects of structure on their properties, the samples were investigated by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and the tensile testing. The samples went through thermo-oxidative ageing and biodegradation; and their effects were investigated. FT-IR and 1H-NMR results showed that three different bio-based resins were synthesized using polycondensation and end-functionalization. Lactic acid derivatives showed great potential to be used as matrixes in polymer composites. The glass transition temperature of the cured resins ranged between 44 and 52 °C. Pentaerythritol/lactic acid cured resin had the highest tensile modulus and it was the most thermally stable among all three resins. Degradative processes during ageing of the samples lead to the changes in chemical structures and the variations in Young’s modulus. Microscopic images showed the macro-scale surface degradation on a soil burial test.
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| 8. |
- Kumar Ramamoorthy, Sunil, 1987-, et al.
(författare)
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Eco-friendly Denim Processing
- 2018
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Ingår i: Handbook of Ecomaterials. - : Springer Publishing Company. - 9783319482811
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Bokkapitel (refereegranskat)abstract
- The denim sector is booming worldwide, because of the spread of denim culture. All over the world it has brought with it a trend of fast-changing fashion. Denim washing has emerged as one of the important production routes toward meeting the fast-changing demands of the fashion market. There are huge ecological concerns, as this sector is enormous. Approximately 1500 gallons of water is needed to produce 1.5 pounds of cotton to make one pair of jeans. If this continues, soon it will pose a serious problem to drinking water supplies. It is therefore important to study the environmental impact of denim and find alternative processes. This chapter starts by describing the different types of denim washing techniques. In addition, it discusses the environmental impact of denim dry and wet washing techniques, and the importance of environmentally friendly washing techniques. It also describes the latest denim finishing technologies, comparing their impacts on the environment with those of the classic techniques. Further, the environmental aspects of auxiliaries and washing chemicals are reviewed, followed by a discussion of garment washing and finishing processes.
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| 9. |
- Kumar Ramamoorthy, Sunil, 1987-, et al.
(författare)
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End of life textiles as reinforcements in biocomposites
- 2017
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Ingår i: Journal of Polymers and the Environment. - : Springer. - 1566-2543 .- 1572-8919 .- 1572-8900. ; , s. -12
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Tidskriftsartikel (refereegranskat)abstract
- A number of attempts have been made to recycle cotton/polyester blend woven fabrics after use; however, most of these fabrics are disposed of in landfills. Major part of these blend fabrics are not recycled due to complexity of the fibre arrangement and cannot be separated economically. This study shows that these discarded woven fabrics could be directly used as reinforcements in composites without fibre separation. Uniform alignment in the woven fabric provided consistent properties to the composites. The fabrics were reinforced by soybean-based-bioresins to produce biocomposites. The composites were analysed for mechanical, thermal, viscoelastic and morphological properties. Porosity and wettability of the composites were also evaluated. Results demonstrate that the tensile strength and modulus of over 100 and 10 MPa, respectively, can be obtained without any fibre treatment. Furthermore, impact strength over 70 kJ/m2 was obtained without any chemical treatment on fibres. The porosity of the composites produced was less than 9 vol%. Additionally, the fabrics were treated with alkali in order to improve the fibre–matrix interface and the composite properties were studied. From the economical perspective, these composites can be produced at a low cost as the major component is available for free or low cost.
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| 10. |
- Kumar Ramamoorthy, Sunil, 1987-, et al.
(författare)
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Mechanical performance of biofibers and their corresponding composites
- 2019
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Ingår i: Mechanical and Physical Testing of Biocomposites, Fibre-Reinforced Composites and Hybrid Composites. - : Woodhead Publishing Limited.
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Bokkapitel (refereegranskat)abstract
- This chapter focuses on mechanical performance of biofibers such as flax, hemp, and sisal and their effect on mechanical performance when they are reinforced in thermoset and thermoplastic polymers. The aim of this chapter is to present an overview of the mechanical characterization of the biofibers and their corresponding composites. The mechanical characterization includes tensile, flexural, impact, compressive, shear, toughness, hardness, brittleness, ductility, creep, fatigue, and dynamic mechanical analyses. Detailed studies of each test have been widely reported and an overview is important to relate the studies. Studies pertaining to the topics are cited. The most common materials used in biocomposites are biofibers (also called natural fibers) and petroleum-based polymers such polypropylene. The use of renewable materials in biocomposites has increased in the past couple of decades owing to extensive research on cellulosic fibers and biopolymers based on starch or vegetable oil. Today, research is focused on reinforcing natural fibers in petroleum-based polymers. However, the emphasis is shifting toward the amount of renewable materials in biocomposites, which has led to the use of biopolymers instead of petroleum-based polymers in composites. The mechanical properties of some renewable resource-based composites are comparable to commercially available nonrenewable composites.Several plant biofibers have been reinforced in thermoplastics or thermosets to manufacture biocomposites because of their specific properties. The Young's modulus of commonly used biofibers such as hemp and flax could be over 50 GPa and therefore they could be good alternatives to glass fibers in several applications. The good mechanical properties of these biofibers influence the composites' mechanical performance when reinforced in polymers. It is important to understand the mechanical performance of these biofibers and biocomposites in a working environment. A detailed discussion about the mechanical performance of commonly used biofibers and composites is provided in this chapter.
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