| 1. |
- Babu, NB Karthik, et al.
(författare)
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Self‐reinforced polymer composites: An opportunity to recycle plastic wastes and their future trends
- 2022
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Ingår i: Journal of Applied Polymer Science. - : John Wiley & Sons. - 0021-8995 .- 1097-4628. ; 139:46
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Forskningsöversikt (refereegranskat)abstract
- Polymers and their composites have played an important role in industrial development. Polymer composites are becoming much stronger and more competitive than other materials as a result of ongoing research and development. This was made possible by newly developed techniques that could alter the physical and chemical properties of constituents. One of them is the self-reinforcement technique, which allows for the fabrication of high-strength thermoplastic polymer composites with reserved degradability, which is not possible with glass fiber/carbon fiber reinforcement. A self-reinforced polymer composite is made of a single polymeric material, which serves as both the matrix and the reinforcement. This review article discusses the use of self-reinforcement in various polymers and its impact on mechanical, thermal, and fire properties. Furthermore, the effects of process parameters (such as temperature and time, an), reinforcement structure, and mechanical property variation on the structure of self-reinforced composites are reviewed and presented in detail. In addition, the effect of foreign filler addition (such as flame retardants, inorganic particles, natural fibers, etc.) on self-reinforced composites is highlighted. In the end, the need for future research and its scope is presented.
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| 2. |
- Chandran, Mathan, et al.
(författare)
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A study of the influence of current ramp rate on the performance of polymer electrolyte membrane fuel cell
- 2022
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Ingår i: Scientific Reports. - : Springer Nature. - 2045-2322. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- Durability and reliability are the key factors that prevent fuel cells from successful implementation in automotive sector. Dynamic load change is a common and frequent condition that the fuel cell has to undergo in automotive applications. Fuel cells are more sensitive to changes in load conditions and degrade based on load variation representing idling, rated power, and high power operating conditions. To examine the influence of dynamic load step on the fuel cell performance, two similar cells of active 25 cm2 was tested under two different load step for the same dynamic load cycle. The main difference in dynamic load cycle 2 was the ramp rate which was fixed as 0.1, 0.3, and 0.25 A/cm2/s for 0.2, 0.6, and 1.0 A/cm2 respectively. To investigate the degradative effects, polarization curves, electrochemical impedance spectroscopy, and field emission scanning electron microscopy were used. The results indicated that the degradation rate increased in both dynamic load cycles but however the impact of load change was comparatively minimal in dynamic load cycle 2. The total degradation in performance was 20.67% and 10.72% in dynamic load cycles 1 and 2 respectively. Fuel cell performance degraded in a manner that was consistent with the electrochemical impedance spectroscopy and cross-sectional analysis of field emission scanning electron microscopy. The results prove that the degradation rate is dependent on the load step and the number of load cycles. Severe catalyst degradation and delamination were observed in fuel cells operated under dynamic load cycle 1.
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| 3. |
- Das, Oisik, et al.
(författare)
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Natural and industrial wastes for sustainable and renewable polymer composites
- 2022
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Ingår i: Renewable & sustainable energy reviews. - : Elsevier BV. - 1364-0321 .- 1879-0690. ; 158
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Tidskriftsartikel (refereegranskat)abstract
- By-products management from industrial and natural (agriculture, aviculture, and others) activities and products are critical for promoting sustainability, reducing pollution, increasing storage space, minimising landfills, reducing energy consumption, and facilitating a circular economy. One of the sustainable waste management approaches is utilising them in developing biocomposites. Biocomposites are eco-friendly materials because of their sustainability and environmental benefits that have comparable performance properties to the synthetic counterparts. Biocomposites can be developed from both renewable and industrial waste, making them both energy efficient and sustainable. Because of their low weight and high strength, biocomposite materials in applications such as automobiles can minimise fuel consumption and conserve energy. Furthermore, biocomposites in energy-based applications could lead to savings in both the economy and energy consumption. Herein, a review of biocomposites made from various wastes and their related key properties (e.g. mechanical and fire) are provided. The article systematically highlights the individual wastes/by-products from agriculture and materials processing industries for composites manufacturing in terms of their waste components (materials), modifications, resultant properties, applications and energy efficiency. Finally, a perspective for the future of biowastes and industrial wastes in polymer composites is discussed.
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| 4. |
- Gawusu, Sidique, et al.
(författare)
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Exploring distributed energy generation for sustainable development : A data mining approach
- 2022
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Ingår i: Journal of Energy Storage. - : Elsevier. - 2352-152X .- 2352-1538. ; 48
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Forskningsöversikt (refereegranskat)abstract
- This study explores how data mining may be used to uncover patterns and trends in the area of distributed generation (DG). It employs the usage of the bibliometric approach. Bibliometric analysis is an increasingly common and rigorous approach for analysing huge datasets in the scientific community. It explains the evolution of a given discipline while highlighting new developments in the sector. To this purpose, this research examines the link between publishing patterns and the underlying technology trends and advances that influence these trends. Also included are key advances in the most recent findings in DG's research. The review finds that past research on system performance and optimization has built a solid conceptual framework for this research domain. The incorporation of new technologies, and the consideration of sustainability issues, are additional areas of concern. The overall strategy and methodologies utilized in this study may be applied to a wide range of research disciplines. Researchers will benefit from this study as a guide for future studies on DG integrating concerns.
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| 5. |
- Jiang, Lin, et al.
(författare)
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Developing an artificial intelligent model for predicting combustion and flammability properties
- 2022
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Ingår i: Fire and Materials. - : John Wiley & Sons. - 0308-0501 .- 1099-1018. ; 46:5, s. 830-842
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Tidskriftsartikel (refereegranskat)abstract
- While there have been various attempts in establishing a model that can predict the flammability characteristics of polymers based on their molecular structure, artificial intelligence (AI) presents a promising alternative in tackling this pressing issue. Therefore, a novel approach of adopting AI methods, extreme learning machines (ELMs) and group method of data handling (GMDH) in estimating heat release capacity, total heat release and char yield from thermophysical properties of polymers were addressed. GMDH showed a clear indication of overfitting whereby the models generated excellent training results but could not provide similar performance during testing. The superior generalisation performance of ELM during testing makes it the standout method. ELM produced HRC predictions having R and RRMSE of 0.86 and 0.405 for training, 0.94 and 0.356 for testing. For THR estimates from ELM, the R and RRMSE scores were 0.9 and 0.195 for training, 0.93 and 0.131 for testing. While char yield ELM model generated 0.88 and 0.795 for training, 0.93 and 0.383 for testing. The potential of ELM was demonstrated as it estimated the flammability parameters of 105 polymers having little or no empirical test results.
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| 6. |
- Khadem, Elham, et al.
(författare)
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Cutting-Edge Progress in Stimuli-Responsive Bioadhesives: From Synthesis to Clinical Applications
- 2022
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Ingår i: Polymers. - : MDPI. - 2073-4360. ; 14:9
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Forskningsöversikt (refereegranskat)abstract
- With the advent of “intelligent” materials, the design of smart bioadhesives responding to chemical, physical, or biological stimuli has been widely developed in biomedical applications to minimize the risk of wounds reopening, chronic pain, and inflammation. Intelligent bioadhesives are free-flowing liquid solutions passing through a phase shift in the physiological environment due to stimuli such as light, temperature, pH, and electric field. They possess great merits, such as ease to access and the ability to sustained release as well as the spatial transfer of a biomolecule with reduced side effects. Tissue engineering, wound healing, drug delivery, regenerative biomedicine, cancer therapy, and other fields have benefited from smart bioadhesives. Recently, many disciplinary attempts have been performed to promote the functionality of smart bioadhesives and discover innovative compositions. However, according to our knowledge, the development of multifunctional bioadhesives for various biomedical applications has not been adequately explored. This review aims to summarize the most recent cutting-edge strategies (years 2015–2021) developed for stimuli-sensitive bioadhesives responding to external stimuli. We first focus on five primary categories of stimuli-responsive bioadhesive systems (pH, thermal, light, electric field, and biomolecules), their properties, and limitations. Following the introduction of principal criteria for smart bioadhesives, their performances are discussed, and certain smart polymeric materials employed in their creation in 2015 are studied. Finally, advantages, disadvantages, and future directions regarding smart bioadhesives for biomedical applications are surveyed.
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| 7. |
- Lin, Chia-Feng, et al.
(författare)
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Fire Retardancy and Leaching Resistance of Furfurylated Pine Wood (Pinus sylvestris L.) Treated with Guanyl-Urea Phosphate
- 2022
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Ingår i: Polymers. - : MDPI. - 2073-4360. ; 14:9
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Tidskriftsartikel (refereegranskat)abstract
- Guanyl-urea phosphate (GUP) was introduced into furfurylated wood in order to improve fire retardancy. Modified wood was produced via vacuum-pressure impregnation of the GUP–furfuryl alcohol (FA) aqueous solution, which was then polymerized at elevated temperature. The water leaching resistance of the treated wood was tested according to European standard EN 84, while the leached water was analyzed using ultra-performance liquid chromatography (UPLC) and inductively coupled plasma–sector field mass spectrometry (ICP-SFMS). This new type of furfurylated wood was further characterized in the laboratory by evaluating its morphology and elemental composition using optical microscopy and electron microscopy coupled with energy-dispersive X-ray spectrometry (SEM-EDX). The chemical functionality was detected using infrared spectroscopy (FTIR), and the fire resistance was tested using cone calorimetry. The dimensional stability was evaluated in wet–dry soaking cycle tests, along with the mechanical properties, such as the Brinell hardness and bending strength. The fire retardancy of the modified furfurylated wood indicated that the flammability of wood can be depressed to some extent by introducing GUP. This was reflected in an observed reduction in heat release rate (HRR2) from 454.8 to 264.9 kW/m2, without a reduction in the material properties. In addition, this leaching-resistant furfurylated wood exhibited higher fire retardancy compared to conventional furfurylated wood. A potential method for producing fire-retardant treated furfurylated wood stable to water exposure has been suggested.
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| 8. |
- Liu, Dongyun, et al.
(författare)
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Correlation between early- and later-age performance indices of early frost-damaged concrete
- 2022
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Ingår i: IABSE Symposium Prague 2022: Challenges for Existing and Oncoming Structures - Report, International Association for Bridge and Structural Engineering. - Zurich, Switzerland : International Association for Bridge and Structural Engineering. ; , s. 934-941
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Konferensbidrag (refereegranskat)abstract
- Freeze‐thaw cycles can lead to serious damage of early‐age concrete and influence its behaviour at later ages. In this study, the later‐age compressive strength, resistance to chloride penetration and resistance to freeze‐thaw of early frost‐damaged concrete were experimentally studied and the relationship between its early‐ (i.e., strength and resistivity) and later‐age (i.e., strength, chloride ion electric flux and freeze‐thaw durability factor) performance indices were analysed. Results show that the later‐age performance of the concrete subjected to freeze‐thaw cycles at early age was generally worse than that of the control samples, which had not undergone early frost damage. This was especially significant for the concrete subjected to freeze‐thaw cycles before the age of 24 h. The compressive strength after early frost action had a higher linear correlation with the later‐age indices of the concrete than the compressive strength before early frost action. Results also showed that the early‐age resistivity is a good indicator for the later‐age performance of early frost‐damaged concrete if the pre‐curing time before frosting is at least 24 h.
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| 9. |
- Mensah, Rhoda Afriyie, et al.
(författare)
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A review of sustainable and environment-friendly flame retardants used in plastics
- 2022
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Ingår i: Polymer testing. - : Elsevier. - 0142-9418 .- 1873-2348. ; 108
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Tidskriftsartikel (refereegranskat)abstract
- The progressive transition from conventional structural designs to lightweight and more complex structures has led to the increase in the quantity of plastic materials in buildings. However, plastics have a major flaw: their low fire performance characterised by shorter ignition times and higher heat release rates. This has necessitated the incorporation of flame retardants (FRs) in plastics. Nevertheless, not all FRs are environmentally safe, hence, there is an urgent need for the development of sustainable biobased FRs that reduce environmental footprints while simultaneously improving the fire performance of plastics. This article addresses the negative connotation of FRs and reviews the most extensively used biobased FRs in plastics, their preparation (synthesis) and mode of application, performance evaluation as well as the leaching of FRs, and environmental fate. Some interesting observations in the review are the reduction of ignition times of plastics by the addition of FRs due to the rapid volatilisation of samples. In addition, the leaching rate of FRs is found to be higher in finer particles (micro and nanoparticles) compared to larger-sized ones and has the potential to dissolve in humic matter hence endangering the lives of humans and animals.
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| 10. |
- Mensah, Rhoda Afriyie, et al.
(författare)
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Influence of biochar and flame retardant on mechanical, thermal, and flammability properties of wheat gluten composites
- 2022
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Ingår i: Composites Part C: Open Access. - : Elsevier. - 2666-6820. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- The use of environmentally friendly materials such as bio-sourced plastics is being driven by increased awareness of environmental issues caused by synthetic plastics. However, bio-sourced plastics have poor fire behaviour that limits their application. The addition of a flame retardant to these plastics is one effective way to increase the fire resistance property; however, the flame retardant should not interfere with the mechanical performance of the plastic. Most flame retardants act as stress concentration points, reducing tensile strength. Hence, to create a balance between tensile strength and fire resistance, biochar (to conserve strength) and lanosol (to improve fire resistance) were added to wheat gluten bioplastic in various ratios and the optimal ratio was identified. Wheat gluten composites were fabricated using compression moulding at four different concentrations of lanosol (2, 4, 6, and 8 wt.%) and biochar (2, 4, 6, and 8 wt.%). From the test results, the composite with 4 wt.% lanosol and 6 wt.% biochar exhibited a good balance between the mechanical and fire properties; it conserved the strength and improved the fire properties (39 % reduction in peak heat release rate).
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