Advances in joining technologies for the innovation of 21st century lightweight aluminium-CFRP hybrid structures

In the twenty-first century, the application of carbon fiber reinforced polymer (CFRP) materials in the vehicle industry are growing rapidly due to lightweight, high specific strength, and elasticity. In the automobile and aerospace industries, CFRP needs to be joined with metals to build complete structures. The demand for hybrid structures has prompted research into the combination of CFRP and metals in manufacturing. Aluminium and CFRP structures combine the mechanical properties of aluminium with the superior physical and chemical properties of CFRP. However, joining dissimilar materials is often challenging to achieve. Various joining technologies are developed to produce hybrid joints of CFRP, and aluminium alloys include conventional adhesives, mechanical and thermal joining technologies. In this review article, an extensive review was carried out on the thermal joining technologies include laser welding, friction-based welding technologies, ultrasonic welding, and induction welding processes. The article primarily focused on the current knowledge and process development of these technologies in fabricating dissimilar aluminium and CFRP structures. Besides, according to Industry 4.0 requirements, additive manufacturing-based techniques to fabricate hybrid structures are presented. Finally, this article also addressed the various improvements for the future development of these joining technologies. Ultrasonic welding yields the maximum shear strength among the various hybrid joining technologies due to lower heat input. On the other hand, laser welding produces higher heat input, which deteriorates the mechanical performance of the hybrid joints. Surface pretreatments on material surfaces prior to joining showed a significant effect on joint shear strength. Surface modification using anodizing is considered an optimal method to improve wettability, increasing mechanical interlocking phenomena.

Pragmaštylistický profil a poverenia titulku v alternatívnej internetovej žurnalistike

The Pragma-Stylistic Profile and the Purpose of Headlines in Alternative Internet Journalism Regardless of the type of carrier, the headline – a signal device and a gateway to a jour­nalistic piece of communication – meets four corresponding criteria. The usual mission of the visually noticeable frame component is to attract the recipients’ attention, to encourage their readiness to respond to the actual piece of communication, to mediate leitmotifs, and to define an acceptable genre affiliation of a journalistic product. Current internet jour­nalism is characterized by significant colloquialization. This manifests itself by blurring the borders between oralness and writtenness (printedness) in communication, in the style and in the ambiguity of the stylistic procedure, as well as by hybrid structures that are con­stantly being generated. Along with the primary functions of communication – stimulating, informative and persuasive function – genre volatility allows the application of other pre-determinations and functions in internet journalism: instructional, expressive, appellative, aesthetic, referential (descriptive), contact and meta-language. These can also be noticed in the pragma-stylistic profile and purpose of headlines. In the paper, the aforementioned processes, trends and consequences are explored using a databank of headlines from alter­native internet journalism. Profil pragmastylistyczny i funkcje nagłówków w alternatywnym dziennikarstwie internetowym Niezależnie od rodzaju nośnika, nagłówek – zapowiedź i wstęp do dziennikarskiego przekazu – spełnia cztery odpowiadające sobie kryteria. Standardowym zadaniem widocznego wizualnie elementu ramy tekstowej jest przyciągnięcie uwagi odbiorców, zachęcenie ich do gotowości reakcji na dany fragment komunikacji, zapośredniczenie motywów przewodnich oraz określenie możliwej do zaakceptowania dla nich przynależności gatunkowej produktu dziennikarskiego. Współczesne dziennikarstwo internetowe cechuje się wysokim poziomem potoczności. Przejawia się to zacieraniem granic między charakterem oralnym a pisanym (drukowanym) komunikacji, stylem i niejednoznacznością środków stylistycznych, a także nieustannym generowaniem struktur hybrydycznych. Wraz z podstawowymi funkcjami komunikacji, stymulującej, informacyjnej i perswazyjnej – zmienność gatunkowa pozwala na odwołanie się w dziennikarstwie internetowym do innych predeterminacji i funkcji: instruk­tażowej, ekspresyjnej, konatywnej, estetycznej, referencyjnej (opisowej), kontaktowej i metaję­zykowej. Potwierdzenie tych zjawisk można również zauważyć w profilu pragmastylistycznym i w roli nagłówków. W artykule wspomniane procesy zostały poddane analizie na materiale z korpusu nagłówków z alternatywnego dziennikarstwa internetowego.

Direct growth of copper(I) oxide nanocubes on graphitic carbon nitrides enhancing aqueous carbon dioxide photoreduction

Semiconductor hybrid structures containing multiple components have been considered an ideal photocatalyst design to generate long-lived charge-separated states. Particularly for the reactions requiring high activation energies, such as a CO2 reduction reaction (CO2RR), the reaction activity is highly susceptible to the catalyst component and morphology. In this study, we selected g-C3N4 and Cu2O as photocatalytic components having bandgaps suitable for CO2RR. Then, we tried to form good electric junctions between two domains by direct growth of Cu on g-C3N4 using a polyol process. The resulting g-C3N4/Cu2O hybrid was employed as photocatalysts in an aqueous medium without hole acceptors. The catalyst exhibited a noticeable activity (5.4 mmol gcat-1h-1) and quantum yield (3.7%) with a nearly quantitative selectivity for CH4 production, superior to any other photocatalysts for CO2RR. The strong coordination of g-C3N4 to the Cu2O surface could form a conductive junction and induce effective electron transfer enforcing the Z-scheme process for CO2RR in high activity and selectivity. This result ensured the importance of junctions and interfaces in the hybrid catalyst structure to exhibit excellent photocatalytic CO2RR performances.

Process gas dependence of the spin Peltier effect in Pt/Fe3O4 hybrid structures

The spin Peltier effect (SPE) in Pt/Fe3O4 hybrid structures with epitaxial Fe3O4 layers synthesized by reactive sputtering using two different process gases, Ar/O2 and Kr/O2, was investigated. The magnitude of the SPE-induced temperature modulation for the Fe3O4 film grown using Kr/O2 was approximately 40% larger than that grown using Ar/O2 despite almost the same crystalline structures and magnetic and electric properties of the films. The enhancement of the SPE signal for the film grown with Kr/O2 can be attributed to an increase in the spin current injected into the Fe3O4 film owing to its large roughness.

Green Synthesis of Silver-Decorated Magnetic Particles for Efficient and Reusable Antimicrobial Activity

Metal and metal hybrid nanostructures have shown tremendous application in the biomedical and catalytic fields because of their plasmonic and catalytic properties. Here, a green and clean method was employed for the synthesis of silver nanoparticle (Ag NP)-SiO2-Fe2O3 hybrid microstructures, and biomolecules from green tea extracts were used for constructing the hybrid structures. The SiO2-Fe2O3 structures were synthesized using an ethanolic green tea leaf extract to form Bio-SiO2-Fe2O3 (BSiO2-Fe2O3) structures. Biochemical studies demonstrated the presence of green tea biomolecules in the BSiO2 layer. Reduction of the silver ions was performed by a BSiO2 layer to form Ag NPs of 5–10 nm in diameter in and on the BSiO2-Fe2O3 microstructure. The reduction process was observed within 600 s, which is faster than that reported elsewhere. The antimicrobial activity of the Ag-BSiO2-Fe2O3 hybrid structure was demonstrated against Staphylococcus aureus and Escherichia coli, and the nanostructures were further visualized using confocal laser scanning microscopy (CLSM). The magnetic properties of the Ag-BSiO2-Fe2O3 hybrid structure were used for studying reusable antimicrobial activity. Thus, in this study, we provide a novel green route for the construction of a biomolecule-entrapped SiO2-Fe2O3 structure and their use for the ultra-fast formation of Ag NPs to form antimicrobial active multifunctional hybrid structures.

Properties of Holographic Elements Based on Periodic Structures in a Wide Range of Angles of Incidence

An experimental study is carried out on the diffraction and angular selectivity properties of gratings for a wide range of angles of incidence in three-dimensional space. Results for three grating types are presented: nonslanted volume gratings, slanted volume gratings, and hybrid structures. The study encompasses a wide range of directions of radiation incidence on structures and reveals grating orientations that can provide maximal diffraction efficiency for angles of incidence of more than 70°. Obtained data are used to assess the efficiency of diffractive deflectors on the basis of the considered structures, taking into account the trajectory of the Sun as applied to solar-energy problems.