REVIEW | doi:10.20944/preprints202311.2005.v1
Subject: Physical Sciences, Optics And Photonics Keywords: metasurface; holography; multiplexing; reconfigurability; multifunctional metadevices
Online: 30 November 2023 (16:09:15 CET)
Metasurface holography offers significant advantages, including a broad field of view, minimal noise, and high imaging quality, making it valuable across various optical domains such as 3D displays, VR, and color displays. However, the conventional pure-structured metasurface holographic devices face a limitation: once fabricated, their functionality remains fixed, restricting practical applications. In recent developments, the landscape of metasurface holography has witnessed a notable shift from passive to active elements, spurred by the introduction of multiplexed and reconfigurable metasurfaces. This paper provides a comprehensive review of the latest advancements in multiplexing and reconfigurable metasurface holography, delving into fundamental characteristics, design strategies, and diverse applications. In conclusion, we offer a brief summary of this rapidly evolving research area, suggest potential future directions, and explore applications. Finally, we briefly summarize this rapidly growing area of research, propose future directions and potential applications.
ARTICLE | doi:10.20944/preprints202308.0789.v1
Subject: Engineering, Other Keywords: Compression moulding, vitrimer, multifunctional composites, epoxy matrix.
Online: 9 August 2023 (14:30:37 CEST)
The need to recycle carbon fibre reinforced composite polymers (CFRP) has grown significantly to reduce the environmental impact generated by their production. To meet this need, thermoreversible epoxy matrices have been developed in recent years. This study investigates the performance of an epoxy vitrimer made by introducing a metal catalyst (Zn2+) and its carbon fibre composites focusing on the healing capability of the system. The dynamic crosslinking networks endow vitrimers with interesting rheological behaviour, the capability of the formulated resin (AV-5) has been assessed by creep tests. The analysis showed increased molecular mobility above a topology freezing temperature (Tv). However, the reinforcement phase inhibits the flow capability reducing the flow. The fracture behaviour of CFRP made with the vitrimeric resin has been investigated by Mode I and Mode II tests and compared with the conventional system. The repairability of the vitrimeric CFRP has been investigated by attempting to recover the delaminated samples, which yielded unsatisfactory results. Moreover, the healing efficiency of the modified epoxy composites has been assessed by using the vitrimer as an adhesive layer. The joints were able to recover about 84% of the lap shear strength of the pristine system.
ARTICLE | doi:10.20944/preprints201811.0002.v1
Subject: Business, Economics And Management, Economics Keywords: Agricultural ExternalitiesPublic GoodsSustainable Agricultural Development Multifunctional Agriculture
Online: 1 November 2018 (18:31:26 CET)
The agriculture and rural areas perform a new function which requires the delivery of public goods to the society. In turn, a comprehensive identification and analysis of agricultural externalities (external economies) involves a need for developing a dedicated valuation methodology. This paper presents the assumptions of the public goods theory and puts them in the context of agriculture. The study focuses on analyzing the valuation methods for external economies, and proposes a methodology for the valuation of some illustrative positive externalities of agricultural production and of natural environment resources regarded as public goods (the agri-tourist value of a farm and the value of a natural waterhole).
ARTICLE | doi:10.20944/preprints202310.1147.v1
Subject: Chemistry And Materials Science, Surfaces, Coatings And Films Keywords: multifunctional composites; thin films; electrical properties; triboelectric nanogenerator
Online: 18 October 2023 (09:36:23 CEST)
A method based on ferroelectric dipole to enhance surface charge density of triboelectric generator was proposed. By using the ferroelectric properties of polyvinylidene fluoride (PVDF), a positive charge trap was formed in the triboelectric layer to enhance the electric generating performance of the triboelectric material, so as to improve the surface charge density of the triboelectric nanogenerator. The PVDF film was fabricated by casting and uniaxial tensile process, and integrated into the triboelectric nanogenerator with vertical separation structure. The influences of the embedding direction, thickness and polarization intensity of the PVDF film on the output of the triboelectric nanogenerator were systematically studied. The results showed that the embedded PVDF piezoelectric film with a thickness of 100 µm and a maximum polarization electric field of 90 MV/m increased the peak power of the triboelectric nanogenerator by 2.6 times. This work has provided a new insight into regulating the properties of the triboelectric nanogenerator.
ARTICLE | doi:10.20944/preprints202107.0708.v1
Subject: Social Sciences, Anthropology Keywords: landscape design and planning; research-by-design; multifunctional agriculture
Online: 30 July 2021 (15:49:35 CEST)
Rural landscapes all over the world are subject to great transformations, first of all the continuous and slow depopulation of land and villages. It is a dramatic phenomenon that causes devastating consequences for environmental systems and for the tangible and intangible heritage of entire territories. The situation becomes more ambiguous when it comes to cultural landscapes, especially those internationally recognized as exceptional (i.e. inscribed on the UNESCO World Heritage List). In this case, the risk is to abandon agricultural production in favor of consumerist tourist economies, which can damage the territorial authenticity. In this paper we question the role of the landscape project in strengthening territorial resilience. In particular, a composite and interdependent action is proposed between landscape design and implementation of a multifunctional agriculture model, oriented towards teaching and tourism. To undertake this investigation, a master's thesis work on Landscape Architecture is examined, as an opportunity for a research-by-design method. The application case is the Italian UNESCO site of Vignale Monferrato, a depopulated rural village, characterized by abandoned land and buildings. The paper concludes by outlining replicability application scenarios for the proposed model.
ARTICLE | doi:10.20944/preprints201810.0502.v2
Subject: Chemistry And Materials Science, Organic Chemistry Keywords: Keywords: Multifunctional polymeric materials; polysilanes; chiral polymers; photoactive polymers.
Online: 26 October 2018 (12:10:41 CEST)
Now-a-days, the thrust area of materials’ research is to develop multifunctional materials, which have multiple properties in a single functional material. We are interested to develop multifunctional polysilanes having special functional properties such as optical activity and photoluminescence (PL) properties. In this investigation, poly(methyl phenyl silane) (PMPS) was integrated with a chiral unit and a photoactive unit by in situ photopolymerization of (R)-N-(1-phenyl ethyl) methacrylamide (R-NPEMAM) and disperse red 1 methacrylate (DR1MA) monomer in the presence of PMPS. PMPS acted as a macrophotoinitiator and by UV exposure it produced macroradicals which initiated polymerization of chiral and photoactive monomers. Thus a block copolymer of PMPS-b-(R-NPEMAM-ran-DR1MA) was synthesized.The synthesized multifunctional organic inorganic hybrid polymer samples were characterized by FTIR and NMR spectroscopy. The molecular weights of the samples were measured by GPC analysis. The optical, chiroptical and photoluminescence properties were studied. The narrow band at about 1638 cm-1 is due to C=O stretching vibration of -CONH- of the chiral unit. A wide absorption peaks at 3444 cm-1 is the characteristic of NH trans stretching vibration of secondary amide group. The asymmetric stretching of NO2 group appeared at 1481 cm-1 and the characteristic peak at 1427 cm-1 was observed due to azo (-N=N-) group stretching of DR1MA unit. The Si-Si band of PMPS appeared at about 462 cm-1 in FTIR spectra. The optical absorbance observed at 272 nm is due to π-π* transition of aromatic ring and at 330 nm corresponds to σ-σ* transition of Si-Si bond. The other electronic absorption observed in the visible region at 475 nm corresponds to the combined contribution of n-π* and π-π* transition of DR1MA unit. The photoluminescence properties of such polymers were studied for the variation of concentration of the polymer solution and variation with excitation energy such as 275 nm, 325 nm and 475 nm in THF solvent. Such synthesized multifunctional photoactive organic-inorganic polymers having unusual optical, chiroptical and photoluminescence property may find novel optoelectronic (friend foe identification and secretive code identification) applications.
REVIEW | doi:10.20944/preprints202309.0572.v1
Subject: Chemistry And Materials Science, Polymers And Plastics Keywords: 3D printing polymers; Additive manufacturing; 4D printing; polymer textiles; multifunctional polymers
Online: 8 September 2023 (08:59:51 CEST)
Three-dimensional (3D) and four-dimensional (4D) printing emerged as the next generation of manufacturing techniques, spanning several research areas such as engineering, chemistry, biology, computing, and materials science. Three-dimensional printing allows the manufacture of complex shapes with high precision, by adding layer by layer of different materials. The use of smart materials that change shape or color, produce an electrical current, become bioactive, or perform an intended function in response to an external stimulus. Shape memory materials (SMMs) in 3D printing technology have attracted a lot of attention due to their ability to respond to external stimuli, leading this technology towards an emerging area of research, "4D printing technology." The core part of this review summarizes the effect of the main external stimuli on 4D textile materials followed by the main applications 4D printed textiles can change their shape over time due to external stimuli such as temperature.
ARTICLE | doi:10.20944/preprints202311.1301.v1
Subject: Chemistry And Materials Science, Materials Science And Technology Keywords: printed flexible sensors; conductive composite; porous structure; micropyramide structure; multifunctional force detection.
Online: 21 November 2023 (10:06:26 CET)
Porous structures and micropatterning surfaces play a crucial role in the development of highly sensitive force sensors. However, achieving these two conductive architectures typically requires complex materials synthesis and expensive manufacturing processes. In this study, we introduce a novel conductive composite film featuring a porous/micropyramid hybrid conductive architecture, which is achieved through a straightforward process of materials mixing and one-step screen printing. By utilizing a deep eutectic solvent in the ink component, micropores are induced in the printed composite, while the mesh of the screen mask acts as a template, resulting in a micropyramid film surface. We have successfully realized highly sensitive flexible force sensors with multifunctional capabilities for perceiving normal force and shear force.
REVIEW | doi:10.20944/preprints202102.0449.v1
Subject: Chemistry And Materials Science, Materials Science And Technology Keywords: multifunctional; hydrogel nanocomposties; tissue engineering; drug delivery; wound healing; bioprinting; biowearable devices
Online: 22 February 2021 (08:48:20 CET)
Hydrogels are used for various biomedical applications due to their biocompatibility, capacity to mimic the extracellular matrix, and ability to encapsulate and deliver cells and therapeutics. However, traditional hydrogels have a few shortcomings, especially regarding their physical properties, thereby limiting their broad applicability. Recently, researchers have investigated the incorporation of nanoparticles (NPs) into hydrogels to improve and add to the physical and biochemical properties of hydrogels. This brief review focuses on papers that describe the use of nanoparticles to improve more than one property of hydrogels. Such multifunctional hydrogel nanocomposites have enhanced potential for various applications, including tissue engineering, drug delivery, wound healing, bioprinting and biowearable devices.
ARTICLE | doi:10.20944/preprints201901.0280.v1
Subject: Physical Sciences, Optics And Photonics Keywords: thin film crystal growth; epitaxial layer growth; multifunctional borate crystals; planar optical waveguides
Online: 28 January 2019 (12:20:05 CET)
We investigated fabrication of neodymium doped thin film optical waveguide-based devices as potential active sources for planar integrated optics. Liquid-phase epitaxial growth was used to fabricate neodymium-doped yttrium aluminum borate films on compatible lattice-matched un-doped yttrium aluminum borate substrates. We observed the refractive index contrast of the doped and un-doped crystal layers by differential interference contrast microscopy. In addition, characterization by X-ray powder diffraction, optical absorption and luminescence spectra demonstrated the crystal quality and uniformity and optical guiding of the resulting thin films.
ARTICLE | doi:10.20944/preprints202304.1099.v1
Subject: Engineering, Other Keywords: multifunctional facade panel; phase change material (PCM); hot box testing; thermal transmittance; numerical simulations
Online: 28 April 2023 (03:49:21 CEST)
This work exclusively focuses on the assessment of the thermal performance of a multifunctional facade panel incorporating PCM in foam layers, recurring to a hot box heat flux meter method to determine the thermal transmittance (U-value). The experimental setup is based on the steady-state approach using climatic chambers, assuring a stable thermal environment. Even small fractions of PCM achieved a small reduction in thermal amplitude. Numerical simulations using Ansys Fluent were developed to evaluate the performance of PCM use over a wide range of temperature boundary conditions and operating modes. These numerical models were calibrated and validated using the results of experimental tests, achieving a correlation factor of 0.9674, thus accurately representing a real-world scenario. The decrement factor (f) was used to analyse the data. It was identified that the efficiency of the panel and size of the optimum region increased with the PCM fraction growth. The simulated behaviour was optimum when the input mean temperature is of 20 °C for a room temperature of between 18-20 °C. The results show the significant potential of the multi-layered panel and the thermal regulator effect of the PCM incorporated on indoor space temperature to reach good thermal comfort levels.
ARTICLE | doi:10.20944/preprints202201.0410.v1
Subject: Chemistry And Materials Science, Physical Chemistry Keywords: multifunctional microcarriers; curcumin; decorated poly(acrylic acid); layer-by-layer (LbL) deposition; antimicrobial function
Online: 27 January 2022 (11:01:46 CET)
The design of multifunctional microcarriers has attracted significant attention because they combine various functions within a single system. In this study, we developed a set of multi-layered hydrogel microcarriers, which were first loaded with chemotherapeutic curcumin (CUR), then using the layer-by-layer (LbL) technique, coated through a polyelectrolyte shell consisting of chitosan (CHIT) or poly(allylamine hydrochloride) (PAH). As an outer layer with antimicrobial function, newly synthesised alkylene quaternary ammonium salt functionalised polyelectrolytes (A-QAS-PEs) were applied. For this purpose, poly(acrylic acid) (PAA) was decorated with dif-ferent hydrophobic side chains (n-hexane and n-dodecane side entities) and different degrees of substitution (m) of quaternary ammonium groups (abbreviated as PAA-C(O)O-(CH2)n-N+(CH3)3(m); n=6,12; m=8-14%). The grafting approach of PAA with the al-kylene quaternary ammonium salt moiety was performed under mild reaction conditions using Steglich esterification followed by quaternisation. The structure of antimicrobial decorated PAA was confirmed by 1H NMR and FTIR, and the mean diameter of all multifunctional microparticles was characterised by SEM. The viscoelastic properties of the functional layers were studied using QCM-D. The release of CUR from the microcarriers was described using a hybrid model, i.e., a combination of first-order kinetics and the Korsmeyer-Peppas model. The antimicrobial activity of functionalised PAA and multilayered CUR-loaded hydrogel microcarriers with quaternary am-monium function was assessed against Staphylococcus aureus and Serratia marcescens by the agar diffusion assay method. Only a limited inhibition zone of PAA was observed, but in the case of both antimicrobial decorated PAA and the corresponding multilayered nanocarriers, the inhibi-tory activity increase was achieved against both strains of bacteria.
ARTICLE | doi:10.20944/preprints202310.0154.v1
Subject: Engineering, Other Keywords: Wearable textile antenna; multifunctional antenna; lattice hinge design; e-textile; polydimethylsiloxane; stretchable antenna; strain sensor
Online: 3 October 2023 (11:57:12 CEST)
The manuscript presents a novel approach to designing and fabricating a stretchable patch antenna designed for strain sensing and wireless communication of sensing data at the same time. The challenge lies in combining flexible and stretchable textile materials with different physical mor-phologies, which can hinder adhesion among multiple layers when stacked up, resisting the overall stretchability of the antenna. The proposed antenna design overcomes this challenge by incorpo-rating a lattice hinge pattern in the non-stretchable conductive e-textile, transforming it into a stretchable structure. The innovative design includes the longitudinal cuts inserted in both the patch and the ground plane of the antenna, allowing it to stretch along in the perpendicular direction. Implementing the lattice hinge pattern over the conductive layers of the proposed patch antenna in combination with a 2 mm thick Polydimethylsiloxane (PDMS) substrate achieves a maximum of 25% stretchability compared to its counterpart antenna without lattice hinge design. The stretchable textile antenna resonates around a frequency of 2.45 GHz and exhibits a linear resonant frequency shift when strained up to 25%. This characteristic makes it suitable for use as a strain sensor. Ad-ditionally, the lattice hinge design enhances the conformability and flexibility of the antenna compared to a solid patch antenna. The realized antenna gains in the E and H-plane were measured as 2.21 dBi and 2.34 dBi, respectively. Overall, the presented design offers a simple and effective solution for fabricating a stretchable textile patch antenna for normal use or as a sensing element, opening up possibilities for applications in communication and sensing fields.
ARTICLE | doi:10.20944/preprints202208.0328.v1
Subject: Engineering, Mechanical Engineering Keywords: thin-film sensors; foil sensors; composite structures; structural bonding; multifunctional bondline; function conformity; sensor integration; structural health monitoring
Online: 18 August 2022 (03:41:32 CEST)
We present an integrable, sensor inlay for monitoring crack initiation and growth inside bondlines of structural carbon fiber reinforced plastic (CFRP) components. The sensing structures are sandwiched between crack stopping polyvinyliden fluoride (PVDF) and a thin reinforcing polyetherimide (PEI) layer. Good adhesion at all interfaces of the sensor system and to the CFRP material is crucial as weak bonds can counteract the desired crack stopping functionality. At the same time, the chosen reinforcing layer must withstand high strains, safely support the metallic measuring grids and possess outstanding fatigue strength. We show that this robust sensor system, which measures the strain at two successive fronts inside the bondline, allows to recognize cracks in the proximity of the inlay regardless of the mechanical loads. Feasibility is demonstrated by static load tests as well as cyclic long-term fatigue testing with up to 1,000,000 cycles. In addition to pure crack detection, crack distance estimation based on sensor signals is illustrated. The inlay integration process is developed with respect to industrial applicability. Thus, implementation of the proposed system will allow the potential of lightweight CFRP constructions to be better exploited by expanding the possibilities of structural adhesive bonding.
ARTICLE | doi:10.20944/preprints201704.0140.v1
Subject: Biology And Life Sciences, Forestry Keywords: common lands; baldios; wild mushrooms; non-timber forest products; Portugal; multifunctional forestry; community; community forestry; local values; forest governance
Online: 21 April 2017 (12:18:11 CEST)
Forest community connections are crucial to ensure forest stewardship and sustainability. We set to explore the potential of mushrooming to enable such connections in contexts were these were historically broken, alienating local people from forests. Taking the case of the recent devolution of a community forest in central Portugal (baldios) to the local population, the authors present a five-year pilot project to rework mycology from a mushroom-centered approach to a mushroom-in-baldios approach. Mushrooms were used as an entry-point to connect the forest ecology with the challenges of governance and community building. The devised activities provided an opportunity for people inside and outside the local community to adventure into the woods, find about their socio-ecological history, develop communal and convivial relationships and engage in the responsible gathering of wild mushrooms. However, the hosting of mushroomers to know, value and engage with the community forest recovery is constantly worked against the enclosure of mushrooms to provide marketable forms of leisure. The outcome will depend on the relationships established between mushrooms, mycologists, local administrators, commoners and poachers, operating within a framework that favors the eradication of resources instead of the long-term relationships that sustain places.
ARTICLE | doi:10.20944/preprints202103.0059.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: Metallothionein (MT); Scientific discovery; Scientific pursuit; Research strategies; upward looking research; Exploratory research; Protein function; Compensation; Moonlighting; multifunctional proteins; Vestiges
Online: 2 March 2021 (09:39:39 CET)
In the mid-1950s, Bert L. Vallee and his colleague Marvin Margoshes discovered a molecule known today as metallothionein (MT). Meanwhile MTs have been shown to be common in many biological organisms. Despite their prevalence, however, it remains unclear to date what exactly MTs do and how they contribute to the biological function of an organism or organ. Honoring Dr. Vallee’s sometimes innovative approach to research, this contribution sets out to show how philosophy of science can help us gain a clearer picture of biochemical research. We shall look into both the discovery of as well as recent research on Dr. Vallee’s beloved family of MT proteins to illustrate (i) how exploratory and upward-looking research play important roles in biochemical discoveries although they do not fit the paradigmatic approach of decomposition and struc-ture-function mapping. Besides, we shall suggest (ii) that while other biochemical molecules ex-hibit a clearly identifiable function, other research hypotheses might be worthy of pursuit in the case of MTs.