High-tech Applications Research Articles

Incremental Roller-Flanging of Thick Metal Sheets

Metal forming industry is frequently characterized by the demand of small-batch productions to manufacture highly customized products. Apart from the accuracy that is mandatory in high-tech applications, one of the main requirements remains the economic competitiveness that becomes critical in the case of the deformation of thick metal sheets due to the relevant forming loads and the large size of the machines that are required to perform such processes. These problems are partially solved by using incremental forming approaches, in which the deformation is gradually performed by the use of one (single point) or two (double-sided) tools that are usually made to slide on the metal sheet surface while they impose the desired deformation. The paper aims at introducing an innovative concept of incremental forming machine to perform double-sided incremental bends, specifically developed for thick metal sheets. The increased flexibility and the possibility to manufacture sound parts with reduced bending forces are shown and discussed.

Binary Pectin-Chitosan Composites for the Uptake of Lanthanum and Yttrium Species in Aqueous Media

Rare-earth elements such as lanthanum and yttrium have wide utility in high-tech applications such as permanent magnets and batteries. The use of biopolymers and their composites as adsorbents for La (III) and Y (III) ions were investigated as a means to increase the uptake capacity. Previous work has revealed that composite materials with covalent frameworks that contain biopolymers such as pectin and chitosan have secondary adsorption sites for enhanced adsorption. Herein, the maximum adsorption capacity of a 5:1 Pectin-Chitosan composite with La (III) and Y (III) was 22 mg/g and 23 mg/g, respectively. Pectin-Chitosan composites of variable composition were characterized by complementary methods: spectroscopy (FTIR, 13C solids NMR), TGA, and zeta potential. This work contributes to the design of covalent Pectin-Chitosan biopolymer frameworks for the controlled removal of La (III) and Y (III) from aqueous media.

WITHDRAWN: Analysis of mechanical behavior of Al 6061 metal matrix with boron carbide and graphite

To meet the demands of today's modern world, traditional materials have many limitations. We need a special kind of material called composite material to solve this. The composite material is made up of two or more materials with different individual characteristics, but when combined, it exhibits the new material with characteristics different from the individual components added. Given their mechanical behaviour, metal matrix composites are highly recommended for high-tech engineering applications. Thanks to their mechanical properties, lightweight, low thermal expansion coefficient, and more significant corrosion and wear resistance compared to other metals and alloys, composites play a critical role in composite material aluminum-based metal matrix composites in the automotive industry, shipyards, and aircraft applications. The work's objective is the manufacture by stir casting technique of aluminium6061-based metal matrix composites strengthened with boron carbide and graphite in various mixing ratios. To determine different mechanical properties and evaluate the effects of reinforcement on the obtained aluminium 6061 metal matrix composite's mechanical behavior, the cast composite is then subjected to various mechanical tests.

Fabrication of Silver-Decorated Graphene Oxide Nanohybrids via Pulsed Laser Ablation with Excellent Antimicrobial and Optical Limiting Performance.

The demand for metallic nanoparticle ornamented nanohybrid materials of graphene oxide (GO) finds copious recognition by virtue of its advanced high-tech applications. Far apart from the long-established synthesis protocols, a novel laser-induced generation of silver nanoparticles (Ag NPs) that are anchored onto the GO layers by a single-step green method named pulsed laser ablation has been exemplified in this work. The second and third harmonic wavelengths (532 nm and 355 nm) of an Nd:YAG pulsed laser is used for the production of Ag NPs from a bulk solid silver target ablated in an aqueous solution of GO to fabricate colloidal Ag-GO nanohybrid materials. UV-Vis absorption spectroscopy, Raman spectroscopy, and TEM validate the optical, structural, and morphological features of the hybrid nanomaterials. The results revealed that the laser-assisted in-situ deposition of Ag NPs on the few-layered GO surface improved its antibacterial properties, in which the hybrid nanostructure synthesized at a longer wavelength exhibited higher antibacterial action resistance to Escherichia coli (E. coli) than Staphylococcus aureus (S. aureus) bacteria. Moreover, nonlinear optical absorption (NLA) of Ag-GO nanohybrid was measured using the open aperture Z-scan technique. The Z-scan results signify the NLA properties of the Ag-GO hybrid material and have a large decline in transmittance of more than 60%, which can be employed as a promising optical limiting (OL) material.

FEM analysis of dispersive elastic waves in three-layered composite plates with high contrast properties

The limitations of the dynamic theories for the thin layered elastic structures, which very often have different physical and geometrical contrast properties of the layers in today's high-tech applications, bring a number of challenges in the numerical computation of the dynamic response. This is a strong motivation to develop a suitable computational methodology for accurate evaluation and implementation of the numerical results, aiming at accurate interpretation of the vibration spectra and the associated displacement and stress fields. In this paper, a newly developed numerical engineering approach is presented for the study of elastic wave dispersion in composite plates (sandwich plates) with high-contrast properties of the layers using modal finite element method (FEM) analysis implemented in commercial software. The obtained results are compared with the iterative numerical solution of the Rayleigh-Lamb dispersion equation for the fundamental flexural wave and the first shear harmonic. It is shown that the complexity of the dispersion phenomena, including the cut-off frequencies of higher order vibrational modes, has been captured very accurately and that the developed computational methodology provides a valuable insight into the frequency range in which the respective mode can be activated. This perspective shows a great potential of the approach to be employed in many engineering applications involving multi-layered structures with arbitrary number of layers.

On-surface preparation of coordinated lanthanide-transition-metal clusters

The study of lanthanide (Ln)-transition-metal (TM) heterometallic clusters which play key roles in various high-tech applications is a rapid growing field of research. Despite the achievement of numerous Ln-TM cluster compounds comprising one Ln atom, the synthesis of Ln-TM clusters containing multiple Ln atoms remains challenging. Here, we present the preparation and self-assembly of a series of Au-bridged heterometallic clusters containing multiple cerium (Ce) atoms via on-surface coordination. By employing different pyridine and nitrile ligands, the ordered coordination assemblies of clusters containing 2, 3 and 4 Ce atoms bridged by Au adatoms are achieved on Au(111) and Au(100), as revealed by scanning tunneling microscopy. Density functional theory calculations uncover the indispensable role of the bridging Au adatoms in constructing the multi-Ce-containing clusters by connecting the Ce atoms via unsupported Ce-Au bonds. These findings demonstrate on-surface coordination as an efficient strategy for preparation and organization of the multi-Ln-containing heterometallic clusters.

Selective separation of polyelectrolyte nanoparticles based on formation of hydrogen-bonding interpolymer complexes

Nano-spherical polyelectrolyte brushes (SPBs) have been demonstrated to be versatile objects for many high-tech applications due to their unique microenvironment and impressive stability in aqueous media, showing great prospects in industry. However, the recycling of valuable SPBs is still a big obstacle, thereby limiting their industrial applications. Here, we show a facile approach to efficiently separate SPBs from aqueous latex solution on the basis of spherical poly(acrylic acid) brushes with a polystyrene core (PS-PAA brushes). Upon addition of poly(ethylene oxide) (PEO), hydrogen-bonding interpolymer complexes consisting of PS-PAA brushes and PEO are formed at pH below 3.5, leading to selective separation of the PS-PAA brushes from aqueous media containing other nanoparticles. Near all of the brushes are separated at pH below 3.0 regardless of the ion strengths. Importantly, the brushes can be easily redispersed by simply increasing pH, showing ignorable variations of the intrinsic properties like diameter, surface charge and light transmittance. As an application example, a catalytic nanoreactor is developed by loading sliver nanoparticles (Ag NPs) in PS-PAA brushes which show neglectable deteriorations of catalysis on the model reaction even after four separation–redispersion cycles. This work provides a simple way for selective separation of SPBs, which may benefit for industrial applications of SPBs.

Chemical reaction powered transient polymer hydrogels for controlled formation and free release of pharmaceutical crystals

Transient materials that function out-of-equilibrium have been of great interest due to their unique properties that are rarely observed in thermodynamically stable occasions. However, the current advances are still limited to supramolecular objects, and the applications using this transient nature remain largely unexplored. Herein we report on chemical fuel powered transient polymer hydrogels for controlled formation and free release of pharmaceutical crystals. The transient polymer hydrogels with highly tunable stiffness and lifetime were created by chemical fuel powered crosslinking, which can be well regenerated without obvious deteriorations by simply refueling. On the basis of these properties, especially the transient nature, these hydrogels can serve as novel reusable platforms to control the pharmaceutical crystallization, more importantly, freely release the obtained crystals, which is inaccessible by conventional static gels. This work is expected to serve as an example to accelerate the development of more advanced out-of-equilibrium materials and exploitations of their high-tech applications.

The Influence of Artificial Intelligence on the Diversity of Plant Design in Landscape Design

With the progress of the times, artificial intelligence and other high-tech applications in our daily life more and more widely. With the acceleration of urbanization process, in the process of rapid development of the city, people not only work and live, but also have higher requirements for the urban environment, and ecological garden construction has also been rapid development. It is an important problem for landscape designers how to allocate plants effectively and give full play to the ornamental and ecological characteristics of landscape. In order to make the plant design research in landscape design keep up with the pace of the development of this era, and make the plant design research in landscape design more successful, this paper puts forward the development method of applying artificial intelligence technology to plant design in landscape design. The application of artificial intelligence technology in modern landscape design is bound to be the development trend of mainstream design. In the practice process of plant design in landscape design, the design method of artificial intelligence is integrated, and some excellent design methods are selected, so as to formulate a set of diversified development scheme which is most suitable for plant design in the new era. Through the analysis, the research method proposed in this paper provides a new development idea for the study of the impact of artificial intelligence on the diversity of plant design in landscape design.

Technology Forgiveness: Why emerging technologies differ in their resilience to institutional instability

Long-term public support may encourage the diffusion of emerging technologies by coordinating the generation of knowledge and providing patient funding, but unexpected policy changes may hinder private investment and even lead to situations of technology lockout. Leveraging archival data; insights from 45 interviews across academia, industry, and government; and 75 hours of participant observations, we develop insights about why institutional instability in Portugal affected the adoption of Polymer Additive Manufacturing (PAM) and Metal Additive Manufacturing (MAM) differently. In both cases, Portugal invested in the technology relatively early. While PAM has been widely adopted, including increasingly in high-tech applications, MAM adoption has been modest despite MAM's potential to greatly improve the performance and competitiveness of metal molds. From the comparison between PAM and MAM, we generate theory about technological and contextual factors that affect ‘technological forgiveness’, defined as the resilience of a new technology's adoption to institutional instability.

Cellulose Nanocrystals Applications in Health, Medicine and Catalysis

Cellulose nanocrystals (CNCs) is one of the outstanding nano-material. So far, much researcher nowadays has been developed their applications. It acquires several properties, particular in bio-degradability and low cost with chemical stability. These properties make CNCs a promising resource to replace fossil resources for the production of industrial materials, chemicals and biofuels. CNCs based materials have attracted much attention during the past few years and are widely used in biomedical materials, pharmaceutical industry, the auxiliary catalytic matrix and nanomedicine were discussed here. The CNCs industry is booming due to many possibilities of drug supply. Successful delivery is influenced by a number of factors, including the selection of suitable materials for research and development. It is used in the transdermal preparations to improve clinical results. It is used as an interdisciplinary approach that takes into accounts, opportunities and potential benefits of developing different management strategies in nature. It has attracted wide attention because of its unique nature, such as renewable, non-toxic, high surface area and the utilization of hydroxyl groups for its functionalization potential to develop various products and replace traditional petrochemical and non-biodegradable materials. This overview summarizes the latest development of model modeling for CNCs. Considerable progress has been made in handling these functions and potentially using of CNCs in different high-tech applications in different areas. This all are highlighted here.

Cyber-physical approach toward semiautonomous postprocessing of additive manufactured parts and components

Additive manufacturing (AM), often referred to as 3D printing, is a generic term describing the layered build-up of material in near net shape frequently attributed with a freedom of design that cannot be achieved otherwise. AM focuses basically on the fabrication of parts for different fields in complex high-tech applications. Examples include components for jet engines, turbines blades, and implants in the medical sector. This is often justified with tool cost savings, shorter lead-time, and overcoming the “design for manufacture” paradigm. On the other hand, a machining allowance is frequently required to counteract the inherent surface roughness and the widespread challenge of part distortion due to residual stresses. At this point, geometrical complexity and small batch sizes transform into strong cost drivers compared to conventional subtractive processing. In fact, these parts are simply hard-to-clamp and hard-to-probe. Moreover, iterative processing is frequently required due to remaining residual stresses in order to reach the target geometry; even the part envelope changes unintentionally. The current paper explores the novel approach of semiautonomous postprocessing of AM parts and components based on flexible clamping, geometry acquisition in the as-clamped position using cooperating laser profile sensors, and an adaptive milling path planning strategy to counteract unforeseen change of the part envelope.

Impact of Cyber-physically enhanced manufacturing on the product requirement documentation in high-tech applications

Conventional machining of high-tech parts and components is often associated with complex processes, long lead times and small to medium batch sizes. Obviously, there is great interest to shorten process development periods and increase process reliability. The transformation of conventional machines into cyber-physical production systems (CPPS) promises significant improvements here. In fact, CPPS allows real-time data acquisition and processing, enabling to target integrated process improvement and quality assurance. In the present work, a methodical procedure for structured data aggregation is introduced for a Cyber-physical enhanced machining process while being explained from a high-tech application point of view. This includes data generation, extraction, transfer and storage, data-consolidation, linkage, visualization and interpretation. Finally, the paper illustrates these aspects in terms of the effects on the “digital product requirements” in order to achieve the presented “analytics-ready” data model using the example of a high-tech application.

Asymmetric D-A-D' Scaffold Inducing Distinct Mechanochromic Luminescence

Mechanochromic luminescence (MCL) materials have a high requirement in high-tech applications such as pressure sensors and data storage. Nevertheless, the diversity of these emitters was still rather restricted owing to...

Sodium silicate-derived aerogels: effect of processing parameters on their applications.

Inorganic silica aerogels derived from sodium silicate are voluminous three-dimensional open networks with exceptional properties such as a density as low as ∼100 kg m−3, high porosity (∼99%), low thermal conductivity (∼0.01 W m−1 K−1), high specific surface area (∼1000 m2 g−1), low refractive index (∼1.05) and high optical transmittance (∼95%) depending on their preparation conditions. They are processed through the sol–gel route, which is a reliable methodology to produce high-grade porous materials. Ambient pressure drying has been developed as a low-cost route for the preparation of sodium silicate-derived aerogels, overcoming the difficulties with the use of organosilane precursors and super critical drying. Silica aerogels can be hydrophobic or hydrophilic depending on their synthetic procedure and surface silanol groups. Owing to their unusual properties, these inorganic aerogels have been applied in both commercial and high-tech engineering applications such as thermal insulation, separation, coatings, optics, nuclear particle detection, sensing, and catalysis. This review provides information on the unique features of a wide array of silica aerogels and their potential applications and recent developments in the field of science and technology.

An overview of biopolymer-based nanocomposites for optics and electronics

We summarize the recent advances in optics and electronics of biopolymer-based nanocomposites. They are emerging as new materials for high-tech applications, thanks to the sustainability of the matrix and the functionalities of the nanofillers.

Gamma attenuation characteristics of CdTe-Doped polyester composites

Polyester is strong and durable material and tends to retain its shape, thus polyester composites have become highly preferred option in high-tech applications. This motivates the usage of polyester composites in the production of radiation shielding materials as well. In present study, gamma ray shielding properties of polyester composite reinforced with different proportions of Cadmium Telluride (5%, 10%, 15% and 20%) have been investigated theoretically and experimentally. The experiments were performed with the use of HPGe detector in a wide range of photon energies varying from 59.5 to 1408.0 keV while XCOM computer program was computed in the same photon energy range to obtain theoretical results and to verify the experimental outcomes. Remarkable radiation protection efficiency was obtained with additive material of Cadmium Telluride, and the radiation protection efficiency was found to be increased with the increase of additive material amount. Negligible discrepancies between experimental and theoretical results were also observed.

Stereoregular hybrid azobenzene-cyclosiloxanes with photoinduced reversible solid to liquid transition properties

A new type of stereoregular hybrid azobenzene-organocyclosiloxane discrete molecular structures with photoactive azobenzene groups unidirectionally connected to rigid cyclosiloxane frames through alkyl spacers of different lengths were developed for the first time.The kinetics and thermodynamics of nondegradative reversible trans-cis photoisomerization processes of the synthesized azobenzene-cyclosiloxane conjugates investigated using UV/Vis spectroscopy, DSC and XRD methods showed dependency on their molecular structures.It has been observed that room temperature UV (365 nm) irradiation of the synthesized hybrids leads to photoliquefaction effect consisting of a photoinduced phase transition of crystal solids into liquids. The photoliquefaction process was observed and confirmed with DSC, XRD and POM methods. Backward solidification process was generated with visible light and by heating.The tetra-azobenzene substituted cyclosiloxane single molecule compounds described in this work can be regarded as promising candidates for the development of new hybrid smart materials with many potential high-tech applications.

Turning On Solid-State Luminescence by Phototriggered Subtle Molecular Conformation Variations.

The development of solid-state intelligent materials, in particular those showing photoresponsive luminescence (PRL), is highly desirable for their cutting-edge applications in sensors, displays, data-storage, and anti-counterfeiting, but is challenging. Few PRL materials are constructed by tethering the classic photochromic systems with newly-emerged solid-state emitters. Selective solid-state photoreactions are demanded to precisely manipulate the luminescent behavior of these emitters, which require dramatic structural change and enough free space, thus limiting the scope of the PRL family. Here, a new PRL material, TPE-4N, that features sensitive and reversible fluorescence switching is reported. The interesting on-off luminescent property of TPE-4N can be facilely tuned through fast phototriggering and thermal annealing. Experimental and theoretical investigations reveal that subtle molecular conformation variation induces the corresponding PRL behavior. The crystalline and amorphous state endows an efficient and weak ISC process, respectively, to turn on and off the emission. The readily fabricated thin-film of TPE-4N exhibits non-destructive PRL behavior with high contrast (>102 ), good light transmittance (>72.3%), and great durability and reversibility under room light for months. Remarkably, a uniform thin-film with such fascinating PRL properties allows high-tech applications in invisible anti-counterfeiting and dynamic optical data storage with micro-resolution.

Phase transition from Au–Te surface alloy towards tellurene-like monolayer

Two-dimensional (2D) chalcogen-based layers have proven to be the next generation of materials for potential high-tech applications, and it is very important to control their properties at the nanoscale. Herein, we discuss the structural and electronic properties of Au(111) surface after being exposed to high temperature vapor deposition of Tellurium (Te) in ultrahigh vacuum. The scenarios entailing the formation of 2D AuTe2 metal dichalcogenide or rather Au–Te alloy monolayer (ML) or even Tellurene single layer deserved to be addressed. In this purpose, low energy electron diffraction (LEED) supported by scanning tunneling microscopy (STM) shows the existence of several surface reconstructions depending on the Te film thickness in the sub-monolayer regime. We observed that the well-known spin-split Shockley state of the Au(111) surface survives the Te deposition and is even shifted to higher binding energy, suggesting a charge transfer at the interface. For a coverage of 0.33 ML of Te, new dispersive bands are observed by angle-resolved photoemission (ARPES), which arise from a strong hybridization between the electronic states of Te and Au. With a substantially low intensity and a back-folding at the boundaries of the reduced surface Brillouin zone (R-SBZ), these electronic bands represent a proof of the existence of a naturel 2D electron gas, strongly disturbed by the surface reconstruction. It is therefore possible that an Au–Te alloy is formed at the surface. By increasing the coverage to 0.5 ML, a rich, thickness-dependent transition develops from the surface alloy to Tellurene-like structure and completely excludes the growth of AuTe2 monolayer. Both the surface alloy and the Tellurene monolayer have a semiconductor character with a gap in the occupied states of about 0.65 eV.