Cellulose nanocrystals, a class of fascinating bio-based nanoscale materials, have received a tremendous amount of interest both in industry and academia owing to its unique structural features and impressive physicochemical properties such as biocompatibility, biodegradability, renewability, low density, adaptable surface chemistry, optical transparency, and improved mechanical properties. This nanomaterial is a promising candidate for applications in fields such as biomedical, pharmaceuticals, electronics, barrier films, nanocomposites, membranes, supercapacitors, etc. New resources, new extraction procedures, and new treatments are currently under development to satisfy the increasing demand of manufacturing new types of cellulose nanocrystals-based materials on an industrial scale. Therefore, this review addresses the recent progress in the production methodologies of cellulose nanocrystals, covering principal cellulose resources and the main processes used for its isolation. A critical and analytical examination of the shortcomings of various approaches employed so far is made. Additionally, structural organization of cellulose and nomenclature of cellulose nanomaterials have also been discussed for beginners in this field.
A haptic-feedback glove with triboelectric sensors and piezoelectric stimulators is developed for interaction in virtual space. Human-machine interfaces (HMIs) experience increasing requirements for intuitive and effective manipulation. Current commercialized solutions of glove-based HMI are limited by either detectable motions or the huge cost on fabrication, energy, and computing power. We propose the haptic-feedback smart glove with triboelectric-based finger bending sensors, palm sliding sensor, and piezoelectric mechanical stimulators. The detection of multidirectional bending and sliding events is demonstrated in virtual space using the self-generated triboelectric signals for various degrees of freedom on human hand. We also perform haptic mechanical stimulation via piezoelectric chips to realize the augmented HMI. The smart glove achieves object recognition using machine learning technique, with an accuracy of 96%. Through the integrated demonstration of multidimensional manipulation, haptic feedback, and AI-based object recognition, our glove reveals its potential as a promising solution for low-cost and advanced human-machine interaction, which can benefit diversified areas, including entertainment, home healthcare, sports training, and medical industry.
Polymeric foams can be found virtually everywhere due to their advantageous properties compared with counterparts materials. Possibly the most important class of polymeric foams are polyurethane foams (PUFs), as their low density and thermal conductivity combined with their interesting mechanical properties make them excellent thermal and sound insulators, as well as structural and comfort materials. Despite the broad range of applications, the production of PUFs is still highly petroleum-dependent, so this industry must adapt to ever more strict regulations and rigorous consumers. In that sense, the well-established raw materials and process technologies can face a turning point in the near future, due to the need of using renewable raw materials and new process technologies, such as three-dimensional (3D) printing. In this work, the fundamental aspects of the production of PUFs are reviewed, the new challenges that the PUFs industry are expected to confront regarding process methodologies in the near future are outlined, and some alternatives are also presented. Then, the strategies for the improvement of PUFs sustainability, including recycling, and the enhancement of their properties are discussed.
Abstract 3D printing, more formally known as additive manufacturing (AM), has the potential to revolutionise the construction industry, with foreseeable benefits including greater structural efficiency, reduction in material consumption and wastage, streamlining and expedition of the design-build process, enhanced customisation, greater architectural freedom and improved accuracy and safety on-site. Unlike traditional manufacturing methods for construction products, metal 3D printing offers ready opportunities to create non-prismatic sections, internal stiffening, openings, functionally graded elements, variable microstructures and mechanical properties through controlled heating and cooling and thermally-induced prestressing. Additive manufacturing offers many opportunities for the construction sector, but there will also be fresh challenges and demands, such as the need for more digitally savvy engineers, greater use of advanced computational analysis and a new way of thinking for the design and verification of structures, with greater emphasis on inspection and load testing. It is envisaged that AM will complement, rather than replace, conventional production processes, with clear potential for hybrid solutions and structural strengthening and repairs. These opportunities and challenges are explored in this paper as part of a wider review of different methods of metal 3D printing, research and early applications of additive manufacturing in the construction industry. Lessons learnt for metal 3D printing in construction from additive manufacturing using other materials and in other industries are also presented.
Abstract Demands for reducing energy consumption and environmental impacts are the major driving factors for the development of natural fiber–reinforced composites (NFRCs) in many sectors. Compared with synthesized fiber, natural fiber provides several advantages in terms of biodegradability, light weight, low price, life-cycle superiority, and satisfactory mechanical properties. However, the inherent features of plant-based natural fibers have presented challenges to the development and application of NFRCs, such as variable fiber quality, limited mechanical properties, water absorption, low thermal stability, incompatibility with hydrophobic matrices, and propensity to agglomeration. Substantial research has recently been conducted to address these challenges for improved performance of NFRCs and their applications. This article reviews the recent advancements of plant-based NFRCs, focusing on strategies and breakthroughs in enhancing the NFRCs’ performance, including fiber modification, fiber hybridization, lignocellulosic fillers incorporation, conventional processing techniques, additive manufacturing (3D printing), and new fiber source exploration. The sustainability of plant-based NFRCs using life-cycle assessment and the burgeoning applications of NFRCs with emphasis on the automotive industry are also discussed.
Biofilms are surface-associated bacterial communities that play both beneficial and harmful roles in nature, medicine, and industry. Tolerant and persister cells are thought to underlie biofilm-related bacterial recurrence in medical and industrial contexts. Here, we review recent progress aimed at understanding the mechanical features that drive biofilm resilience and the biofilm formation process at single-cell resolution. We discuss findings regarding mechanisms underlying bacterial tolerance and persistence in biofilms and how these phenotypes are linked to antibiotic resistance. New strategies for combatting tolerance and persistence in biofilms and possible methods for biofilm eradication are highlighted to inspire future development.
For the last decades, nanocomposites materials have been widely studied in the scientific literature as they provide substantial properties enhancements, even at low nanoparticles content. Their performance depends on a number of parameters but the nanoparticles dispersion and distribution state remains the key challenge in order to obtain the full nanocomposites’ potential in terms of, e.g., flame retardance, mechanical, barrier and thermal properties, etc., that would allow extending their use in the industry. While the amount of existing research and indeed review papers regarding the formulation of nanocomposites is already significant, after listing the most common applications, this review focuses more in-depth on the properties and materials of relevance in three target sectors: packaging, solar energy and automotive. In terms of advances in the processing of nanocomposites, this review discusses various enhancement technologies such as the use of ultrasounds for in-process nanoparticles dispersion. In the case of nanocoatings, it describes the different conventionally used processes as well as nanoparticles deposition by electro-hydrodynamic processing. All in all, this review gives the basics both in terms of composition and of processing aspects to reach optimal properties for using nanocomposites in the selected applications. As an outlook, up-to-date nanosafety issues are discussed.
Polymer-ceramic piezoelectric composites, combining high piezoelectricity and mechanical flexibility, have attracted increasing interest in both academia and industry. However, their piezoelectric activity is largely limited by intrinsically low crystallinity and weak spontaneous polarization. Here, we propose a Ti3C2Tx MXene anchoring method to manipulate the intermolecular interactions within the all-trans conformation of a polymer matrix. Employing phase-field simulation and molecular dynamics calculations, we show that OH surface terminations on the Ti3C2Tx nanosheets offer hydrogen bonding with the fluoropolymer matrix, leading to dipole alignment and enhanced net spontaneous polarization of the polymer-ceramic composites. We then translated this interfacial bonding strategy into electrospinning to boost the piezoelectric response of samarium doped Pb (Mg1/3Nb2/3)O3-PbTiO3/polyvinylidene fluoride composite nanofibers by 160% via Ti3C2Tx nanosheets inclusion. With excellent piezoelectric and mechanical attributes, the as-electrospun piezoelectric nanofibers can be easily integrated into the conventional shoe insoles to form a foot sensor network for all-around gait patterns monitoring, walking habits identification and Metatarsalgi prognosis. This work utilizes the interfacial coupling mechanism of intermolecular anchoring as a strategy to develop high-performance piezoelectric composites for wearable electronics. The piezoelectricity of PVDF composites is mainly determined by the crystalline phases and spontaneous polarization. Here, the authors propose a Ti3C2Tx anchoring method to modulate the molecular interactions and conformation of polymer matrix.
Multidiscipline application of triboelectric nanogenerators (TENGs) for intelligent Internet of Things (IoTs) are summarized from the aspects of agriculture, industry, city, emergency monitoring, and artificial intelligence. Perspectives on the challenges and future research directions of TENGs in IoTs have been proposed. Multidiscipline application of triboelectric nanogenerators (TENGs) for intelligent Internet of Things (IoTs) are summarized from the aspects of agriculture, industry, city, emergency monitoring, and artificial intelligence. Perspectives on the challenges and future research directions of TENGs in IoTs have been proposed. In the era of 5G and the Internet of things (IoTs), various human–computer interaction systems based on the integration of triboelectric nanogenerators (TENGs) and IoTs technologies demonstrate the feasibility of sustainable and self-powered functional systems. The rapid development of intelligent applications of IoTs based on TENGs mainly relies on supplying the harvested mechanical energy from surroundings and implementing active sensing, which have greatly changed the way of human production and daily life. This review mainly introduced the TENG applications in multidiscipline scenarios of IoTs, including smart agriculture, smart industry, smart city, emergency monitoring, and machine learning-assisted artificial intelligence applications. The challenges and future research directions of TENG toward IoTs have also been proposed. The extensive developments and applications of TENG will push forward the IoTs into an energy autonomy fashion.
Recent advances in aircraft materials and their manufacturing technologies have enabled progressive growth in innovative materials such as composites. Al-based, Mg-based, Ti-based alloys, ceramic-based, and polymer-based composites have been developed for the aerospace industry with outstanding properties. However, these materials still have some limitations such as insufficient mechanical properties, stress corrosion cracking, fretting wear, and corrosion. Subsequently, extensive studies have been conducted to develop aerospace materials that possess superior mechanical performance and are corrosion-resistant. Such materials can improve the performance as well as the life cycle cost. This review introduces the recent advancements in the development of composites for aircraft applications. Then it focuses on the studies conducted on composite materials developed for aircraft structures, followed by various fabrication techniques and then their applications in the aircraft industry. Finally, it summarizes the efforts made by the researchers so far and the challenges faced by them, followed by the future trends in aircraft materials.
Abstract Magnesium (Mg) alloys, owing to their lightweight, have gained substantial attention in industries such as aviation and automotive. Researchers are continuously working on different strategies to improve the performance of Mg alloys, among which alloying is of prime importance. However, care has to be taken so as to avoid over alloying of Mg as that would degrade the lightweight advantage of Mg. Addition of gadolinium (Gd) and yttrium (Y) to magnesium holds promise for improving mechanical performance, but a detailed comprehension of their synergetic effect on alloy’s microstructure and deformation behaviour is crucial, which forms the basis of this study. Mg alloys with varying percentage of Gd and Y are developed in this study using gravity casting method. Microstructural assessment revealed a complex interplay of phases, including the presence of eutectic structures among other strengthening precipitates. Distribution and morphology of these microconstituents are studied in detail through electron microscopic techniques. Mechanical performance of the materials is assessed through tensile testing. Results indicated that the incorporation of Gd and Y influenced critical resolved shear stress (CRSS) values, affecting the activation of specific slip systems and twin systems. Post-deformation analysis preformed through fractography provided valuable information on the fracture modes and failure mechanisms, contributing to a comprehensive understanding of the alloy’s reliability. Mechanisms leading to a typical microstructure and a resultant mechanical performance for Mg-Gd-Y alloy is discussed in detail.
Alfarabi Habil Muhammad, Fauzan, Faris Zaiem Al Hakiem
et al.
This study proposes and evaluates a car seat-integrated heat pump as localized air conditioning system for electric vehicles (EVs). The proposed system uses R1234yf and comprises a compressor, microchannel heat exchangers, an electronic expansion valve, and a four-way reversing valve for bidirectional operation, delivering conditioned air through the internal seat ducts to the cushion and backrest. A horizontal twin-rotary compressor was developed, which exhibits high isentropic and volumetric efficiencies. The compact module, with a height of 145 mm, a width of 330 mm, a length of 484 mm, and a mass of 20 kg, can be installed under the seat while satisfying the standard SgRP/H30 envelope constraints. Testing was conducted in controlled environmental chambers across representative operating conditions with various airflow rates at different temperatures of 30 °C and 35 °C for cooling and 7 °C and 15 °C for heating. At a typical compressor speed of 4000 rpm, the proposed system achieved coefficient of performance (COP) values of 3.5–5.5 and 4.5–8 in cooling and heating modes and cooling and heating capacities of 650–900 W and 400–600 W, respectively. Concentrating thermal control at the seat is expected to provide rapid, occupant-level cooling/heating with favorable efficiency, indicating a practical path to EV energy savings and thermal comfort.
Breffní Lennon, Tamara Hajdu, Niall P Dunphy
et al.
Forming energy communities and the governance structures needed to facilitate their development is proving more difficult than previously foreseen. This is evidenced by the rather uneven development of sustainable energy communities in Europe and beyond. Living labs offer a useful pathway for co-creating the dynamic renewable energy ecosystems needed to foster user-driven innovation, particularly with regards to integrating digital technology into the engagement practices of citizens in new energy communities. This paper uses the COM-B Model of behaviour to explore the potential of living labs in facilitating more active participation and co-creation among stakeholders, particularly in terms of integrating demand response strategies that foster collaborative end-user engagement. Indeed, it is this interplay between information and communication technology (ICT) and innovation which emerges from living labs that can empower participants to co-design solutions that are more responsive to real-world needs. Also, it should lead to fostering more sustainable changes in behaviour and improve the efficacy of the technical solutions available to us. This paper presents recent findings from multinational European research utilising the living lab model and the collaborative environment it provided for citizens to vision the types of participation they prioritise in bridging the gap between technological potential and user-centric innovation. Such collaborative, co-learning opportunities offer a means towards ensuring current ICT advancements align with the practical demands of the low-carbon societies we wish to create.
Renewable energy sources, Energy industries. Energy policy. Fuel trade